World Environmental and Water Resources Congress 2010: Challenges of Change

When a small community experiences significant growth in a short period of time the impact on land and water use greatly affects the surrounding areas. Madison County Alabama was once a small farming community but has experienced a 40% growth over the past two decades. This growth has led to environmental concerns over the amount of pollution in the major watershed, the Flint River. This study was performed to determine bacterial concentrations along the length of the river as it passes from the agricultural county, to the City and eventually to the Tennessee River, to observe whether there is a gradual rise in the concentration of E. Coli and Coliform colonies as the river travels. This sampling was performed under "winter," wet weather conditions to determine if there are risks for individuals living along the river banks and for the county water supply. This type of information is especially beneficial in a dynamic, high flow condition such as the Flint River in Alabama.

Tile drainage systems transfer leached nitrate to bodies of water and contribute to hypoxia in the Gulf of Mexico. Performance of denitrification of woodchip bioreactors was conducted through column experiments at various retention times. Field tile water (10–11 mg/L NO₃—N) was pumped through columns packed with wood chips at three different retention time (8, 6.3, and 4.2 hours). Soil was used to amend the column media to test if additional bacteria would enhance denitrification. Synthetic tile water was prepared (12 mg/L NO₃—N) and used to test for the presence of denitrifying bacteria in wood chips. Effluent nitrate concentrations were found to be dependent on the retention time. Removal efficiencies were found to be of 39, 76 and 96% at 4.2, 6.3 and 8 hours of retention time, respectively. Based on the results of this experiment, effluent nitrate concentrations below the EPA's MCL requirements of 10 mg/L NO₃—N are possible with longer retention times. Additionally, these results suggest that utilization of denitrifying bioreactors could be feasible to reclaim California groundwater if the nitrate content is above MCL's and the water is not intended for drinking.

Urbanization of watersheds can affect surrounding surface and ground water quality. The watershed study conducted tried to reveal origins of non-point source runoff within the important Flint River Watershed in North Alabama. The land use of the area has greatly changed from agriculture to an urbanized area. A more technology driven economy in Madison County, AL prompted the change. The watershed studied did not have much historical data in the sites of the main channel that were tested. Most non-point pollution sources are credited to urban and agricultural runoff. Finding locations along the river that have changes in or high amounts of runoff can be beneficial to protecting the area and preventing further problems. This paper explains the sample collection and discusses the problems encountered, both in not finding enough historical data and with water quality. One of the benefits of this study was gathering data that can be used in future studies to allow better watershed management plans to be put into action.

Suspended sediment concentration and yields were studied in the Town Creek watershed in the Southeastern Plains Ecoregion, Mississippi in order to identify suspended sediment transport trends and possible mechanisms driving sediment supply and exportation within and from Southeastern Plains watersheds. Mean flow, and suspended sediment concentrations, loads and yields from grab samples monitoring at 7 stations along the principal channel were evaluated. High spatial and temporal variability of flow and suspended sediment concentrations, discharges and yields were observed within the watershed. Erosive processes dominate suspended sediment transport in northern headwater channels, while deposition tends to control the sediment transport process in downstream channels. A suspended sediment transport relation was developed indicating (1) a low availability of suspended sediment for low flow or base flow conditions and (2) storm flows were responsible for exporting suspended sediment from the watershed. Adoption and implementation of management practices are necessary within Town Creek watershed to have measurable improvements in water quality. The suspended sediment analysis presented in this document could be used to characterize suspended sediment loads and yields within similar Southeastern Plains Ecoregion watersheds.

The objective of this study was to quantify the effects of ozone level used as a water disinfectant on corrosion of cement-mortar lined ductile iron pipe. This research is focused on the interaction of two factors, ozone level and flow rate, on cement-mortar lined ductile iron pipe corrosion. Ozone addition was set for three levels 0.0, 0.5 and 1.0 ppm. Flow rates were set at 0, 20, and 40 gallons per minute (0, 0.076 and 0.15 m³/minute). To obtain results in a controlled laboratory system, hardness and fluoride concentration were fixed at 60 to 120 ppm and 1ppm respectively. Ambient values of pH (5.0 to 8.0 s.u.), and chlorine, (free and total) in the range of 0.0 to 1.0 ppm, were set and monitored. In addition, temperature was controlled in the range of 20 +/–5°C (degrees centigrade) using a submersible heater. A closed recycle system was used to observe changes over time and to simulate actual field conditions. The circulating pump was run to simulate normal water usage in a distribution system with flow on 12 hours and off 12 hours during a 24 hour period. Ozone addition was on only when the water flow was on. The on/off cycles were controlled by a timer. Each test point was run for two weeks and then replicated for a second two weeks. Iron level was observed to increase over time with the addition of ozone while flow had little or no effect at the rates studied. Based on these findings, corrosion, measured as iron in solution, increased with larger doses of ozone and its associated ammonia. Flow had little or no affect on corrosion.

The objective of this paper is to present a dynamic model to predict trends of future metal contents. We use stratification of different environmental compartments which are presented by aggregated blocks. The influence of local peculiarities of river watershed and industrial sites should be averaged to be reflected in model parameters.. We assess the levels of cooper and zinc based on data regarding average values of mentioned metals observed for three years. One of main issues of studying the water chemical composition in a system with spatial heterogeneities and several sources of pollution is defining local parts with almost equal conditions.. The model system for a local part can be brought to the form that is described by coupled oscillators as well. Coupled oscillators interact via mutual adjustment of their amplitudes and phases. Synchronization results from mutual adjustment of oscillators that gives rise to a common dynamical behavior.

A major impact of climate change is likely on the frequency and magnitude of extreme flow events. Hydrological systems have traditionally been designed on the assumption that the available flow records for a location reflect stationary climatic conditions. In view of the recent climate change, the assumption of stationarity in the flow records cannot be justified. Design of hydrological systems is, therefore, likely to be more reliable if the impacts of potential climate change on extreme events are considered. This paper investigates trends in extreme flow measures for a set of streamflow gauging stations in Satluj River Basin in India. Linkages of extreme flow measures with large scale climate indices have also been identified. The analysis includes an exploration of the types of trends that may occur in an extreme flow record, which include changes in the timing of extreme events, and changes in the extreme event magnitudes. Several extreme flow measures including the high flow and low flow magnitudes and their dates of occurrence have been analyzed for the detection of trends using Mann-Kendall non parametric test. The results reveal more trends than would be expected to occur by chance for various measures of extreme flow characteristics. The data has been found to exhibit changes in both the magnitude and the timing of extreme flow events. Analysis of extreme flow measures presented herein is likely to lend credibility to recent climate change modeling efforts, and would help detect climate change impacts on hydrological regime.

This paper presents results about potential effects of climate change on the hydrology and water resources in the Rio Conchos basin, with special emphasis on the transboundary water treaty signed between the US and Mexico in 1944. The Rio Conchos watershed, the main tributary of the lower portion of the bi-national Rio Grande/Bravo basin, is located in Chihuahua State in northern Mexico. The most relevant problem in the basin is the frequent occurrence of long drought periods, such as those that occurred in 1950s, 1960s, and the most recent from 1992 to 2003. Coupled with increased water demand and low irrigation efficiencies, the competition for water resources is high on both sides of the border. This paper reports on part of an assessment of expected climate change impacts in the basin. The methodology includes: 1) developing a model that represents the hydrological behavior of the basin; 2) analyzing downscaled climate data from five General Circulation Models (GCMs), for emission scenarios A2 and A1B; 3) simulating the basin under these climate change scenarios; 4) assessing the impacts of climate change on the hydrology and water resources in the basin; and 5) simulating and evaluating water management scenarios that could be used to adapt to the expected climate impacts in the coming decades. Some results from tasks (1) and (2) are reported here. These indicate a negative trend of precipitation in the area over the next few decades. Consequently, streamflow is projected to be lower by more than 18% at the basin outlet (Ojinaga station at the confluence with the Rio Grande) for scenario A2. Moreover, seasonal runoff analysis shows that winter and summer flows will be reduced more than 25% by the end of the century. Trend analysis also indicates negative trends over time. In addition, the change in runoff concentration and periodicity was explored in this research.

An understanding of the effect of climate teleconnection patterns on the hydrological cycle is important for the long term management of water resources. In this paper we examine the effect of ENSO on surface runoff in the Rio Grande basin. The watershed, which is shared between the U.S. and Mexico, is vital for the economic activities of both countries. The runoff values, obtained at 1/8° resolution, were generated by the NOAH land surface model driven using the NLDAS2 datasets for the period 1979–2008. The basin was divided into 6 distinct regions and analyzed separately. The land surface model realistically captured the hydro-climatic variations across the basin. Continuous wavelet plots of NINO 3.4, gauged rainfall and model runoff were produced and a strong correlation between ENSO and runoff was observed.

The projected changes to streamflow for a river basin in the Pacific Northwest U.S. are investigated using statistically downscaled output from 8 global climate model projections. The downscaled meteorological data is used to drive three hydrology models with different complexities: the Sacramento Soil Moisture Accounting (SAC-SMA) model, Conceptual Hydrologic MODel (HyMOD) and Thornthwaite-Mather model. This is meant to consider the uncertainty in hydrologic model selection. The uncertainty in model parameterization is addressed by calibrating the models with three different objective functions. The total uncertainty is investigated for dry (summer) and wet (winter) season for two emission scenarios namely A1B and B1 in each GCM. The results show that the hydrologic uncertainty is considerably smaller than climate uncertainty where the total uncertainty for dry season is higher than the one in the wet season. The runoff change for future periods relative to the reference period is also examined showing the decrease in runoff by moving further to future time slices especially in dry seasons.

Streamflow timing has shifted for many streams across New England (Hodgkins 2003, USGS 2005). Current climate change forecasts project this trend to continue as a result of earlier snow melt, increased evapotranspiration, and more precipitation falling as rain during the winter season. Climate change requires the development of new operating policies for reservoirs throughout the region. This research addresses the potential impacts of climate change on reservoir operations within two watersheds of the Connecticut River Basin by generating a set of future streamflow data for 2025, 2050, and 2075. Two watersheds in the Connecticut River basin with dams that operate to meet hydropower and flood control objectives were selected to demonstrate climate impacts on different management goals. Climate data from General Circulation Models (GCMs) and two emission scenarios were downscaled. These data were used to establish a temperature and precipitation alteration for each future year of interest that was then used in calibrated hydrology models of each watershed to generate streamflow representative of climate change. Climate adjusted streamflow data were created to be incorporated into optimization models that replicate current dam operations and that can generate alternative operations that mitigate the undesirable effects of climate change. These changes in operational rules will provide stakeholders evaluation tools to investigate different adaptation strategies and determine which strategy best suits each basin.

A framework for climate change adaptation decision making by water and wastewater utilities is presented. The framework employs the classic event tree mechanism for defining risk events. In this application, empirically-based event trees are used to describe in detail the probabilistic pathways by which climate risk events can impact a utility, and to define the consequences of these events with and without adaptive actions. Depending on the level of analysis required, the size of the utility, and the availability of data inputs, event trees can be used both qualitatively and quantitatively to provide a robust framework to guide water utilities in their decision making for climate change.

Climate variability and change continue to threaten the sustainability of water resources around the world. Increasing temperature is likely to modify the timing, form, and intensity of precipitation events, which will alter regional and hydrologic cycles. Since drought, water shortages, and subsequent water conflicts may become an increasing threat in many international watersheds, sustainable water resources planning is critical to cope with climate change. In this study, the authors propose a framework of sustainable water resources planning based on coupled hydroclimate modeling and decision support tools to promote collaborative efforts against abrupt future climate change. A participatory modeling approach based on a stakeholder-driven decision support system will provide useful insights for water planners to pursue sustainable water resources under uncertain future climate. Additionally, the framework suggested by this study will facilitate multidisciplinary responses to future climate variability in the context of socioeconomic implications and policy decisions in human dimensions

In recent years, the potential impacts of climate variability and change on the hydrologic regime have received a great deal of attention from researchers. Review of hydrological data recorded in different parts of the world has provided evidence of regime-like or quasiperiodic climate behaviour and of systematic trends in key climate variables due to climate change and/or climate variability. It has been established that a changing climate will have notable impacts on the rainfall runoff process, and thus hydrologic time series (e.g., flood data) can no longer be assumed to be stationary. A failure to take such change/variability into account can lead to underestimation/overestimation of the design flood estimate, which in turn will have important implications on the design and operation of water infrastructures. This paper presents preliminary results from a study aimed to identify the nature of time trends in flood data in the Australian continent with the final objective of assessing the impacts of climatic change on regional floods in Australia. This research is being carried out as a part of the on-going revision of Australian Rainfall and Runoff — the national guide of design flood estimation in Australia. For this study, 491 suitable stations with flood data in the range of 30 to 97 years have been selected across the Australian continent. Two trend tests are applied: Mann-Kendall test and Spearman's Rho test to the data set. Preliminary trend analysis results show that about 30% of the selected stations show trends in annual maxima flood series data, with downward trends in the southern part of Australia and upward trends in the northern part. Further investigation is needed before any firm conclusion can be made about the trends in Australian flood data. Future work aims to address the influence of spatial correlation and autocorrelation on the ability to detect trend in annual maximum flood series data in Australia and assess the relationship between the observed trends in annual maximum flood data and other meteorological variables.

This study incorporates climate change and urban development scenarios into regional water demand projections. A disaggregated water demand model is coupled with an advanced urban simulation model (UrbanSim) to generate demands at detailed spatial resolution. The difference between including changes in variables such as density, income, and other demographic indicators is evaluated. The region in which this study takes place is the Puget Sound Region of the United States, which is located in the Pacific Northwest (Figure 1). This area has a population of over 4.2 million people and includes the cities and suburbs of Seattle, Tacoma, Everett, and Bellevue, Washington. The Puget Sound Region has experienced rapid growth during the past decade, with a 10% change in population from 2000 to 2008 (357,000 additional residents). This rate of growth is slower but similar to that which occurred in the 1990's when 525,000 residents were added to the region (a twenty percent increase in population). In 2000, two-thirds of the population resided within incorporated areas, in 1990 that ratio was 50/50. The growth from 2000–2008 continues the migration to incorporated areas, with growth concentrated primarily in existing dense urban areas but some new growth in the urban fringe. Seattle's center has experienced the development of condominiums creating residential space along with increasing redevelopment of single-family lots into multiple townhome style single-family homes. The development along the urban fringe has increased the density of housing, but large lots and residences are still the norm. Population within the region is projected to continue to increase, with an additional 1.7 million residents from 2000 to 2040 (roughly a million households). Most population increases are in the one and two resident households, suggesting large increases in multifamily populations and townhomes. This estimate agrees with the current trends of growth in the major urban areas (Seattle, Tacoma, Bellevue, and Everett) and is an important factor in future urban growth patterns. The climate is considered Mediterranean, in that the majority of precipitation falls during winter months, and the summers are unusually dry. The vast majority of the drinking water for this region is supplied by surface water. The lack of over-year storage capacities in the reservoirs results in a delicate balancing act between meeting summer water demands and maintaining environmental flows for ESA listed species. Accurately projecting water demands ensures that this balance is maintained and future water supply projects come online as needed.

Climate change will have numerous and diverse impacts on the environment, including those on ambient water quality. In areas projected to experience decreased runoff (e.g., in many semiarid areas), water quality deterioration will be even more pronounced. The number of waterbodies recognized as impaired is likely to increase, even if pollution levels remain stable. However, projected climate change impacts on ambient water quality and Total Maximum Daily Load (TMDL) have been studied relatively little. The objectives of this paper are to review available water quality studies in the context of climate change and recommend ways in which a few key issues in water quality programs (e.g. critical condition, uncertainty analysis) should be adapted to reinforce effective water quality management in a changing climate. This paper reviewed water quality issues in a climate change context from several available studies that extend to different waterbody types (stream, lake, and estuary) and conducted a preliminary comparison between threshold approach and scenario approach. It also provided a summary of threshold approach and scenario approach, including major advantage and disadvantage of both approaches, for evaluating climate change impact on ambient water quality and related TMDL program. Case studies reviewed in this paper included climate change evaluation on long-term water quality by U.S. Environmental Protection Agency (USEPA) Chesapeake Bay Program and consideration for incorporating climate uncertainty in the upcoming Bay TMDL, a river in Mid-Atlantic region using USEPA BASINS Climate Assessment Tool, and a nutrient-impaired lake in the Northeast. In response to the statement that "stationarity should no longer serve as a central, default assumption in water-resource risk assessment and planning", trade-offs need to be made between ambient water quality simulations using either long-term historical data series or stochastic predictions of such data based on properties of the historical time series. It is important to assess the pollutant loading estimate and future effectiveness of a water quality program or TMDL implementation plan under projected climate change scenarios as well as under different management actions in response to climate. The water quality management and permitting programs will need to adapt by considering the long-range implications for waterbody impairment associated with climate change and make needed revisions to TMDL guidance and water quality-based effluent limitations (e.g. under future "lower low-flow" condition). Ongoing studies will equip policymakers with the information and decision tools required to cost-effectively adapt to climate change impacts on water quality management.

A holistic investigation of aquifer storage and recovery (ASR) technique and application in the U.S. is being conducted as a part of the USEPA Water Resources Adaptation Program (WRAP). The research focus is to evaluate the potential of ASR application as a practical climate change adaptation tool. Specifically, the investigations are centered on ASR's technical feasibility, regulatory implications, and engineering techniques for field applications: 1) need for ASR to mitigate water budget imbalance; 2) environmental impacts and potential regulatory implications; and 3) adaptation techniques and engineering guidelines for sustainable ASR development. This paper describes the ASR research framework and the initial research results on the ASR needs and environmental consequences. In assessing the need in future climate, geographic regions with likely imbalance between water demand and water availability are identified. This analysis relies on a nationwide hydroclimatic study of historical and future precipitation changes, an evaluation of future water demand variations, and a hydrological analysis of candidate geological strata. The second part of the research was conducted to address how the ASR operations can be sustainable in avoiding environmental impacts to the storage media and groundwater quality. The results are critical for assessing the adequacy of current ASR engineering practices and regulations. Quantitative experimental studies have been conducted to study the presence of recalcitrant endocrine-disrupting compounds (EDCs) and aldicarb (as a model pesticide) in reclaimed water, evaluate their fate and transport at an ASR site, and to investigate arsenic remobilization and secondary arsenic contamination to groundwater. These deterministic studies were conducted using bench-scale and pilot-scale soil column experiments, activated sludge and membrane bioreactor for wastewater treatability studies, in situ atomic force microscopy of arsenic-bearing mineral dissolution, as well as two-dimensional ASR modeling of hydrologic and water quality kinetic processes. Preliminary research results show the ASR feasibility in water resource adaptation to climate changes, and have laid a technical basis for further developing ASR engineering techniques with managed environmental impacts.

Climate change and socioeconomic developments have resulted in an ever increasing imbalance between the water supply and demand in many parts of the world, including the southwest U.S. To secure sustainable water resources, aquifer storage and recovery (ASR) techniques are investigated as a part of the climate change adaptation tools in the U.S. EPA Water Resources Adaptation Program (WRAP). This investigation is centered on arsenic dissolution and re-mobilization from arsenic-bearing pyrites during the ASR process. Various sizes of ASR applications are reported throughout the U.S. with the majority being located in the Southwest, Florida, and the Midwest. ASR wells are subject to the Underground Injection Control (UIC) Program's Class V regulations under the Safe Drinking Water Act. In addition to concerns of macronutrient and biological contaminant impacts, there are reports on the mobilization of metals from the aquifer matrix of these sites. Arsenic is one of the commonly observed metal contaminants in groundwater, potentially resulting from oxidation and dissolution of arsenic-bearing pyrite. A series of experimental studies are underway to quantify the mechanisms of arsenic dissolution from arsenopyrite host and the subsequent arsenic transport in an ASR application. In controlled bench-scale experiments, the arsenic-bearing pyrite dissolution rate is determined with the use of in-situ atomic force microscopy (AFM). AFM provides quantitative measurements of arsenopyrite morphology changes during the dissolution process. Separately, two ASR simulation soil columns measured at 6.1-m in height and 45.7-cm in diameter are used to simulate the physiochemical changes in aquifer materials and to quantify the arsenic dissolution-mobilization-transportation process. The two columns of identical experimental set-ups allow comparative studies of arsenic fate and transport in natural groundwater flow and in ASR operation using reclaimed wastewater after chlorination. In this paper, we will describe the preliminary experimental results and discuss the implications for ASR operations and the knowledge gaps for further studies.

A detailed temporal and spatial analysis of precipitation data has led to conclude that topographic forcing played an important role in regulating the frequency and distribution of high-intensity precipitations in the contiguous U.S. In this investigation, 129,000 station-year historical precipitation data obtained for 1207 climatic stations were analyzed using wavelet time-frequency techniques. The results show prominent precipitation variability spatially in association with major topographic features in six hydroclimatic provinces and their transitional zones: (1) Western Coast, (2) Ranges and Basins, (3) Great Plains and Midwest, (4) Lower Mississippi — Ohio River valley — New England region, (5) Florida and Southeast coast, and 6) Great Lakes. Each province has its own unique characteristics of precipitation variability. In this paper, the focus is to discuss the role of topographic forcing in precipitation variability and its implications to water resources engineering. Two types of major topographic effects are discussed. One is topographically enhanced precipitation variability in the U.S. southeast and the Gulf states. The second is the large-scale effect of surface water bodies, as shown by the long-term precipitation increase in the Great Lakes hydroclimatic province. These examples highlight the important role of topographic forcing in regional-local precipitation variability, and depict a superposition of the topographic forcing over the synoptic climate dynamics.

Serving as an expert witness is both a vital service to the judicial system and can be a significant secondary source of income to an engineer. However, an engineer who is hired to render an expert opinion should be cognizant of the fact that he/she does not want to be known in the legal community as a "professional expert" or an expert whose primary source of income is rendering expert opinions in courts of law, particularly for one specific client or industry. Such "professional experts" are looked upon skeptically by many lawyers as not having the requisite professional gravitas to remain employed in their profession and/or are of the opinion that not staying actively involved in the day-to-day practice of their speciality blunts their professional expertise. Furthermore, serving the cause of only one client or classification of clients (i.e., just plaintiffs or just defendants or a particular corporate entity) gives an impression of bias, that you are an advocate for a client, or that your expert opinion is not independent but "for sale".

The Kansas City market has listened weekly to "Water, Water Everywhere" on AM talk radio since January 2009. The show has been sponsored by the University of Missouri-Kansas City School of Computing and Engineering, City of Kansas City Water Services Department, the City of Independence, Missouri Water Pollution Control Department and the Kansas City Section of ASCE. The show is promoted by the radio station, a website, a blog and Twitter account. The show is streamed live online and podcasts of all past shows are available without subscription. The show's host is a local environmental engineering professor, and the interviews have ranged from sewer improvements to architectural stormwater solutions to astrophysics. The show's goals are to provide gentle education of water-related projects and to promote the profession by highlighting successful projects.

Women are becoming less of a rarity in civil engineering faculty within the past twenty years, but there remain unresolved issues keeping the numbers relatively low. This article presents a brief history of women in the profession and discusses some of the issues affecting women in civil engineering, particularly in academia. A survey was composed and distributed to female faculty from ASCE Region Four and Five schools. This data includes demographics, status of mentoring, views on job satisfaction and feelings of inclusion in a male-dominated arena. As females show progress in academia it is theorized that the numbers of female students will also increase, thus strengthening engineering profession.

This paper describes the results of a two year assessment of whether engineering students modify their perspectives on "sustainability" because of exposure to topics of real economics and risk in their coursework. In conjunction with Villanova University's "Year of Sustainability", implied and explicit considerations of "sustainability" issues were introduced into our "Economy & Risk" course. An evaluation of resulting effects on students' awareness of and perspectives on issues of sustainability was attempted. For example, on day one of the class, students were asked to write a short meaning of sustainability. Examples of the many and varied one-word answers ranged from "long-term" (33% ) to "no idea" (10%). Comparison of word association studies reported for environmental science students with the results from CEE students revealed interesting differences. The environmental science department surveys (Sherman, 2008) reported that the most commonly associated words were mainly prescribed practices (recycling, composting, etc. [90%]); only 5% responded with a "bigger idea", such as "systems" or "balance" and 5% picked environmental problems (global warming, biodiversity). Only 14% of the CEE students identified "sustainability" with prescribed practices; 18% chose environmental problems; while 56% of the responses were "long-term" or similar words. The remaining 12% were either non-responsive or admitted "no idea" [4%]. These engineering students clearly had a much different "view of sustainability" than did the environmental science students. The CEE students were also required to critique Solow's paper describing an economist's view of sustainability (Solow, 1991) intended to expand their perspectives on such issues. Finally, these students were given an essay question on the final exam that asked them to explain how this course had influenced their respective understanding of sustainability. They claimed that they had learned that "sustainability" was a vague term and that it involved not so much preserving particular resources but rather the capability (including the roles of technology and knowledge) for future generations to succeed. Most students had clearly expanded their respective understanding of the questions surrounding sustainability and the engineering role. However, a number said they hadn't changed their opinion about the need for activities commonly labeled sustainable. The assigned work of 114 students enrolled in two consecutive offerings of the course (Fall 2008, Fall 2009) was used to address two major questions. The first question was whether the content of the course had been effective with respect to promoting sustainability knowledge. The second was to assess whether it had "influenced" students' thoughts about sustainability issues. Results did not differ significantly between the two classes.

CEE 2814, Measurements, is a four credit hour required course of all Civil and Environmental Engineering, Building Construction, and Construction Engineering Management students. During the summer of 2009 a teaching module was developed to introduce the concept of sustainable design from a land surveying perspective. The authors selected the use of global positioning systems (GPS) to illustrate the concept of sustainability through increased efficiencies. This paper will highlight specific examples of the use of GPS in industry to increase efficiency, and thereby provide traditional services in a more sustainable manner. Specifically, the authors will look at the waste management industry and how a 10% savings in truck travel and fuel was achieved by using GPS in conjunction with route optimization software. Also investigated is the doubling of productivity by using GPS to assist in grading operations at land development sites. Lastly, the paper looks forward to the potential use of GPS by the Federal Aviation Administration to more effectively route planes through the United States air traffic system. This is in a system where a single airline estimated that landing each of their planes one minute sooner could result in fuel savings of $25 million in a year.

Joseph G. Totten, a notable 19^th century civil engineer, spent almost a quarter of his professional career in Rhode Island. From 1825 to 1838, Totten, a young Corps of Engineers officer, supervised the construction of Fort Adams, the third largest coastal fortification in the United States, at the entrance to Narragansett Bay near Newport, Rhode Island. His experience there not only provided the nation with a first-of-its-kind coastal fortress, but also enabled him to become the proponent and designer of what has come to be known as the "third system" of the nation's coastal fortifications. Following his assignment at Fort Adams, Totten was appointed Chief of Engineers of the U.S. Army Corps of Engineers. He served in that capacity for more than 25 years—more than twice as long as any other Chief of Engineers. This paper provides an overview of Joseph Totten's work, with emphasis upon his work at Fort Adams and the relationship between that work and the development of the nation's third system of coastal fortifications.

The history and performance of iron pipe is reflected in the successful growth of great cities worldwide. No other product used in our cities' infrastructure has played such a fundamental role in the development of these population centers. Iron pipe carried the water and wastewater that allowed the metamorphosis from rural farming communities to urban centers of commerce and set the stage for public health improvements, financial strength, and growth. History has shown that iron pipe has been, and continues to be, a valuable asset in municipal infrastructure. Iron pipe is believed to have been used for the first time circa 1455, in Siegerland, Germany, where an unknown size and quantity of iron pipe was installed to provide water service to Dillenberg Castle. Records indicate that approximately two centuries later, and 690 kilometers (429 miles) to the east, Louis XIV ordered the construction of a 24-kilomoter (15-mile) pipeline to serve the city and fountains of Versailles, France. This iron pipeline provided continuous service for more than 330 years. Use of iron pipe for water service in the United States began in Philadelphia when, "in a major construction project lasting almost 30 years and ending in 1848, city engineers laid a network of cast-iron pipes." (Kramek and Loh, 2007). Some of the first iron pipe installed in Philadelphia was imported from England, because there was no domestic manufacturer until the 1834 establishment of a pipe foundry in Millville, New Jersey. Recent reports from the Environmental Protection Agency indicate gray and ductile cast iron pipes now comprise roughly two-thirds of the United States' massive water infrastructure. This paper will continue the discussion of iron pipe history by focusing on the evolution of the domestic pipe industry and the changes that are recognized as major product development benchmarks. This will include detailed descriptions of developments in manufacturing processes, metallurgy, joints, and corrosion control. Wherever applicable, the paper will provide details and explanations of pipe features that impact utility owners' ability to more accurately assess the condition of their buried iron pipe infrastructure.

Just over 100 years ago in 1906, the first hydroelectric station was constructed in the state of Colima, Mexico. The turbines produced over 650 kW of electricity and harnessed over 100 meters of head. Colima is a small state located on the Pacific coast of Mexico near Guadalajara. Compañía de Potencia y Luz Eléctrica de Colima, S.A. (Colima Power and Electric Light Company) under the leadership of its president, Arnoldo Vogel von der Wettern, developed the plant. This was the first electric plant in the state, and it provided service to Comala, Villa de Álvarez, and the City of Colima. In 1967, the Federal Electricity Commission (CFE) acquired regional electric companies including this one, and the Commission closed the hydroelectric plant. In recent years, the Colima state government has launched an ambitious historical preservation project associated with the project.

The Missouri University of Science and Technology is a member of a relatively small number of institutions that focus primarily on engineering studies. The prescriptive nature of ABET-accredited curricula means that the opportunities for undergraduate students to study abroad over either the short or long terms are limited. An interdisciplinary group of faculty members working on international water-related research projects developed a campus-wide undergraduate minor proposal intended to attract students interested in international studies without regard to the students' major fields of study. A critical aspect of the minor was the desire by the originators to have the minor administered independently of any degree program so as to maintain an independent (or "international") spirit. Housing the minor at the campus level instead of the academic department level created a unique set of concerns and challenges which required considerable time to address. The most organized resistance to the minor came from some humanities and social science faculty members. The administration of the minor is thus highly defined, and the three- year plus time period required to formally establish the minor resulted in several lessons learned that may be of interest to others who want to pursue interdisciplinary programs. The minor is currently administered by a group of faculty from engineering, physical and natural sciences, liberal arts, and business degree programs; and it is expected that the 2009–2010 academic year will yield the first generation of students in the minor program.

The science and management of environmental- and water-related issues requires an interdisciplinary approach, as recognized by funding agencies, consulting firms, and public organizations. In their role of preparing students for productive professional careers, academic institutions should be able to train students in interdisciplinary approaches, but complications exist in current academic environments that make interdisciplinary education especially challenging. We provide a vision of interdisciplinary graduate education in water and environmental resources in 2050 after presenting a brief assessment of current issues in interdisciplinary education.

Chlorine is widely used as an inexpensive and potent disinfectant in the United States for drinking water. However, chlorine has the potential for forming carcinogenic and mutagenic disinfection by-products (DBPs). In this study, bench scale experiments were conducted at the U.S. Environmental Protection Agency's (EPA's) Test and Evaluation (T&E) Facility in Cincinnati, Ohio on peracetic acid (PAA), an alternative disinfectant for drinking water which is purported to reduce DBP formation. PAA has been extensively studied as a disinfectant in wastewater and to a lesser extent in drinking water. The tests were carried out in a nanopure water matrix. The total organic carbon (TOC) level in the test water was increased to target levels of 0.5 to 1.5 mg/L by the addition of humic acid. E. Coli was added as the target microbial organism at initial concentrations of 10⁶ Colony Forming Units (CFU)/100 ml. PAA doses were varied from target levels of 0.5 to 2.5 mg/L for contact times of 10 minutes. E. Coli log removal rates above 4.5 were achieved for disinfectant concentrations above 1 mg/L and were insensitive to TOC levels. DBP analyses did not detect any total trihalomethane production (TTHMs) arising from the disinfection process. No conclusions could be drawn concerning bacterial regrowth in the disinfected samples. Future work will compare disinfection efficiency and DBP production of PAA with Twin Oxide ^TM, a chlorine dioxide based powder disinfectant.

Small community systems that use surface water as a source of drinking water are frequently faced with elevated levels of naturally-occurring organic matter (NOM) that are not removed by conventional filtration methods. These residual levels of NOM can then combine with chlorine used for disinfection and create disinfection byproducts (DBPs) that could potentially exceed the regulatory limit for various DBPs. Additional treatment for removal of these DBP compounds may be required for compliance with the requirements of the Safe Drinking Water Act (SDWA). The formation of DBPs can be prevented by removing NOM which act as DBP precursors. This paper presents the results of experiments conducted on two nanofilter membrane systems with a patented method for cleaning the membrane using a foam ball. The tests were conducted at the U.S. EPA Test & Evaluation (T&E) Facility (using dechlorinated potable water with the addition of humic acid to simulate NOM) and at a field site using lake water. The treatment system uses a tubular membrane with the ends connected to effectively form a single, long, membrane. A foam ball is periodically passed through the inside of the membrane by reversing the flow direction to scour the membrane surface and remove accumulated organic matter capable of fouling the membrane surface. This organic matter is then discharged by back-flushing the membrane. The effectiveness of the system in producing drinking water was gauged by measuring the turbidity, color, and organic content of the system inlet and outlet. Tests were also performed using the aerobic spore Bacillus subtilis (B. subtilis) as a surrogate for bacteria removal and MS2 bacteriophage as a surrogate for virus removal.

This paper reports on results of pilot and field-scale studies of treatment of the Aquarion Water Company (AWC) Lantern Hill groundwater source that has elevated levels of both reduced iron and manganese and natural organic matter (NOM); typical raw water quality is: pH 6.5, 1.5 mg/L Fe, 0.15 mg/L Mn, 3 mg/L TOC. Existing treatment consists of three parallel pressure media filters (21 inches of anthracite over 24 inches of a greensand media) preceded by sequential in-line addition of potassium hydroxide, free chlorine, potassium permanganate and a synthetic cationic polymer. Chlorination of the raw water results in unacceptable levels of filter effluent DBPs. Pilot-study results for addition of a second stage high-rate coarse media filter for Mn removal and moving chlorination from pre- to post first stage dual media filtration show dramatic decreases in DBP formation and excellent removal of Fe, Mn and NOM.

The United States Environmental Protection Agency (EPA) Office of Research and Development has evaluated the performance of a Point-of-Use (POU) pour-through device designed for use in India, developing and emerging market (D&E) countries, and under emergency situations in the United States. In collaboration with the Unilever Research India, a series of microbial tests were conducted on a Unilever Pureit^TM microbiological purifier for household drinking water at the EPA's Test and Evaluation Facility in Cincinnati, Ohio. The Pureit^TM water treatment system is fed by gravity and combines the unit operations of physical filtration, chlorine disinfection, and carbon adsorption for treating drinking water. EPA evaluated the Pureit^TM device for removal of E. coli (as a surrogate for bacteria), and MS2 bacteriophage (as a surrogate for viruses). Results demonstrated that the Pureit^TM system achieved EPA requirements of a 6 log reduction of bacteria and a 4 log reduction of virus for a "Microbiological Purifier" throughout the design life of the device (~ 2250 liters). The final polisher of the unit was capable of reducing the residual chlorine concentration to less than the EPA's 2 mg/L maximum limit for tap water.

The U.S. Environmental Protection Agency (EPA) initiated a research program in 2008 at the EPA Test and Evaluation (T&E) Facility in Cincinnati, Ohio to evaluate the performance of various Point-of-Use (POU) treatment devices for providing drinking water in homes and transient non-community water systems, either routinely or as an emergency measure during accidental or intentional contamination events. This paper describes the results of the performance of two POU devices based on reverse osmosis (RO) technology. The POU devices were continuously operated for about 22 months (670 days) to evaluate their long-term performance and challenged with microbiological contaminants at different time intervals to evaluate continued treatment effectiveness. The microbiological contaminant challenge contaminants included E. coli, MS2 bacteriophage, B. subtilis and polystyrene latex (PSL) beads (evaluated as a non-biological surrogate for Cryptosporidium). The results of tests conducted to date show complete removal of the selected microorganisms and surrogates by the POU systems both at startup and after 22 months of operation. The two RO-based POU systems satisfied the Long-Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR) requirements for Cryptosporidium removal. The POU devices performed favorably when compared to the reduction requirement of the EPA Guide Standard Protocol for Microbiological Water Purifiers (U.S. EPA, 1987), which is 6 log for bacteria and 4 log for viruses.

As urbanization continues to increase and climate changes continue to impact our water cycle, the importance for understanding the complex interactions occurring between and within the urban and natural environments continues to be more important. When considering an urban center, the intake of water — primarily for potable water production — is impacted by the interplay of the hydrological cycle with both the natural and engineered systems located upstream of that center. Within an urban center, the production of potable water is utilized for both potable and non-potable uses and must satisfy a complex, sometimes conflicting set of regulatory constraints. These systems also must handle changes in water use through conservation efforts, development of "grey water" infrastructure, and continuing challenges to protect public health. The return of this water back to the environment through the sewer and storm water system is challenged by an increasingly aged infrastructure that must avoid direct discharges of untreated water into the receiving waters; and, factoring the potential benefit of low impact development, on improving and maintaining these systems as the hydrologic cycle changes. As the water then leaves the urban center, the remaining water quantity and quality now impacts the downstream natural and urban environments, where the urban water cycle repeats itself. Understanding the complex interactions within one of these natural or urban systems, let along the interactions between them, is a challenging but necessary objective if we are to continue developing sustainable water resource strategies into the future. The role of the developing "observatories" will be an important part of collecting the data necessary to understand these complex, spatially diverse systems. The additional role of "cyber-infrastructures" as data repositories and simulation frameworks will provide the platforms to amplify research efforts by making this information available to research groups throughout the world. The following sections describe out on-going efforts in developing the cyber-infrastructure for implementing an urban observatory within drinking water distribution systems.

Data describing the stream flow, water chemistry, geomorphology, and biology of streams and rivers is often contained in a variety of formats and in many geographic locations. A prototype environmental flows information system is developed for the State of Texas that incorporates relevant known available datasets from federal, state, academic, river basin, and local sources. Tools are developed to assist in the publishing, visualization, and access of data and documents via map-based, spreadsheet-based, and other methods. The information system might be used to provide: (1) rapid low-cost data integration, (2) improved data access by the public, and (3) support for the analysis and determination of environmental flow needs. The environmental flows information system represents the integration of the physical, chemical, and biological information for rivers and streams in a consistent and accessible manner in one system in one place. Working cooperatively with the Consortium of Universities for the Advancement of Hydrologic Science, Inc. (CUAHSI) Hydrologic Information System (HIS) project, an NSF-supported effort to improve access to hydrologic data at the nation's universities, environmental flows data are stored in the CUAHSI Observations Data Model and web services are established for the computer-to-computer communication of data in order to extract data from disparate sources in disparate formats, to transform the data into the common language of CUAHSI WaterML, and to load the data into an end user's system. The environmental flows information system includes a linkage to a georeferenced digital archive of documents, providing for parallel access to both data and the knowledge products derived from that data. Via the Data Model and accompanying Document Model, an information system capable of managing observational data, geographic data, modeled/constructed data, and documents is offered.

The Earth Systems Division within NASA has the primary responsibility for the Earth Science Applied Science Program and the objective to accelerate the use of NASA science results in applications to help solve problems important to society and the economy. The primary goal of the Earth Science Applied Science Program is to improve future and current operational systems by infusing them with scientific knowledge of the Earth system gained through space-based observation, assimilation of new observations, and development and deployment of enabling technologies, systems, and capabilities. This paper discusses one of the major problems facing water resources managers, that of having timely and accurate data to drive their decision support tools. It then describes how NASA's science and space based satellites may be used to overcome this problem. Opportunities for the water resources community to participate in NASA's Water Resources Applications Program are described.

In this paper, we present an integrated Real-Time Geospatial Sensor Web and Visual Analytics systEm (RT-GeoSWAVE), which allows user-driven creation and visualization of derived "virtual sensors" that transform and repurpose existing sensors for real-time situational awareness. We illustrate this cyber-sensing system through a near-real-time urban flooding and sewer overflow scenario in Chicago, where NEXRAD Level II data are converted through a series of spatial, temporal and thematic transformations to a group of persistent polygon-based virtual rainfall sensors at the urban hydrological unit scale (i.e., sewersheds), which in turn can be visualized on demand as a real-time animated movie in space and time on the integrated Web-based Google Earth to assess rainfall patterns in an urban sewershed. Such a system is invaluable for real-time decision support as the spatial distribution of intense rainfall significantly impacts the triggering and behavior of urban flooding and sewer overflows. Furthermore, the system also demonstrates a critical capability for environmental observatories that will enable their users to dynamically evolve a suite of derived data products to meet changing research and management needs.

Hypoxic or dead zones, which occur when dissolved oxygen levels in water drop below 2 mg/L, are prevalent worldwide. An example of such an hypoxic zone forms intermittently in Corpus Christi Bay (CCBay), Texas, a USEPA-recognized estuary of national significance. Hypoxia in CCBay occurs primarily due to inflow of hypersaline waters that enter from adjacent bays and estuaries, fluctuations in oxygen levels due to the oxygen production-consumption cycle of the aquatic flora and fauna, seasonal fluctuations, and lastly, discharges from several wastewater treatment plants. The aim of this paper is to create more accurate and efficient near-real-time forecasts of hypoxia that will give researchers advance notice for manual sampling during hypoxic events. The approach involves developing and testing a suite of data-driven model fusion approaches with the help of cyberinfrastructure. The models that will be used as a part of this study are: a data-driven k-nearest neighbor model (Coopersmith, 2008), and a physics-based valve model (Sin Chit To, 2009). The k-nearest neighbor predicts the probability of occurrence of hypoxia 24 hours later, and the levels of dissolved oxygen. On the other hand, the valve model determines the distance traveled by a gravity-current upon entering Corpus Christi Bay from adjacent estuaries and bays and the period of time it persists. A comparison will be made between the results of the fused model and those of the individual models to test the effectiveness of model fusion in predicting the estuarine condition in the model.

The detection and characterization of breaking waves using X-band pulsed Doppler microwave radar are studied experimentally. Field experiments were conducted at the Shuang-Si estuary in the north of Taiwan in the winter of 2005. Results show that the maxima radar cross section and Doppler frequency shift can be used to characterize wave breaking zones. Base on observations of breaking waves, the wave breaking zones are shown to be located at water depths of 1.8 to 2.2 m in the experimental site. In general, the results indicate that a radar system has the potential to delineate the spatial variation of breaking waves clearly and that this is sufficient to achieve a measurement operation for near-shore air-sea interaction events.

Considering the range of space and timescales involved and the diverse nature of watershed-scale processes, environmental measurements can only be meaningful when they are performed long-term at high spatial-temporal density. The establishment of coastal observatories will depend a lot on our ability to obtain such high density datasets requiring long-term in situ unattended data acquisition. Also, the interplay of environmental and forces and bio-geochemical cycling necessitates long-term studies and different variables need to be measured to develop adequate forecast and response systems. Since nutrients partition to particulate matter, embayment productivity can be directly correlated with particulate matter mass flux at flux points or across system boundaries. Without the prerequisite sensors our ability to quantify those fluxes will be limited. Particulate biogenic matter (e.g., phytoplankton) in surface waters is directly related to water quality. Phytoplankton abundance can be an indicator of aquatic health in lakes, bays and estuaries which can be linked to exceedingly high productivity most often due to high nutrient (N, P) loading into the receiving water body. According to the 2000 report from the Committee on Environment and Natural Resources, the annual cost of HABs in the US is $300–$700 million. However there has been relatively small progress in developing dynamic sensor systems for bio-chemical characterization of aquatic environments to date, seriously hampering the development of effective monitoring programs for critical water resources. Against this backdrop, bio-chemical sensors are required to enable better understanding of human-dominated water-environments, their stressors, and the links between them. There is a need for novel instrumentation to measure and monitor two critical nutrients nitrogen and phosphorous (total and available N, P) in surface and ground waters concurrent with determination of the impact of nutrient loading on important biota in real time. Phytoplankton growth kinetics is also critical to water quality models but the representation of biomass based on chlorophyll-`a' measurements can lead to erroneous parameterization of such models. Proper quantification of phytoplankton abundance should be a key thrust of instrumentation development which will combine both the quantification of biomass growth (specifically plankton) with information obtained on the underlying biochemical cycling (nutrients, CO₂). With advancements in photonics, the enabling technology exists in image processing, pattern recognition, digital imagery, high-resolution optical detectors, and we can match this challenge. Efforts are now geared towards developing sensor array designed purposely to be a near real-time nutrient sensor directly coupled with a trainable optical recognition particle identification and characterization unit to detect and identify biogenic particles. The ability to track N and P loading and biomass in real-time will afford the scientific community the opportunity to develop improved water quality models and better resource management programs for the nation's water resources.

In 2003, the Kentucky Research Consortium for Energy and Environment (KRCEE) was created at the University of Kentucky through the efforts of US Senator Mitch McConnell. The Consortium's mission was to provide technical support to the US Department of Energy (US DOE), the US Environmental Protection Agency (US EPA), and the Kentucky Division of Waste Management regarding non-consensus issues associated with clean-up efforts at the Paducah Gaseous Diffusion Plant National Priority List Superfund site. In 2009, KRCEE was asked to develop a community-based end state vision that would encompass the range of community perspectives and preferences for the site's future after US DOE closes the facility. This paper provides an overview of the methodology that has been developed and is being implemented as part of this process, as well as lessons learned in interfacing with a diverse set of stakeholders.

The Paducah Gaseous Diffusion Plant is a uranium enrichment facility built in the mid-1950s in western Kentucky. Many thousands of people over several generations have been employed at, or in activities devoted to, the PGDP. Over the years, the plant has also generated significant nuclear and industrial contamination. This contamination is composed of various surface disposal activities, such as burial grounds, which have resulted in multiple potential sites across the plant grounds, and in surface and subsurface water contamination, the extent and full nature of which is still subject to ongoing research and monitoring. Because of this, the PGDP retains a joint legacy as a regional economic engine and a major source of environmental contamination and worker exposure. Because of advances in the technology of uranium enrichment, however, there are expectations that the plant eventually will be decommissioned. This will result in dramatic impacts on the region's economy and encourage the pursuit of replacement activities for the site. This, in turn, will highlight the complications arising from various sorts of contamination, as well as the strategies for mitigating them. Thus, envisioning a future for the plant site is a complex decision making process involving a wide range of variables that interact with each other in intricate and not altogether-understood ways. Proactively involving the affected community in a productive way is the challenge.

This paper describes the role of Community-Based Participatory Communication in a multiphase research project that will incorporate community values into a publicly approved Future State Vision Report for the Paducah Gaseous Diffusion Plant (PGDP) National Priority List Superfund site and surrounding areas. The project, funded by the U.S. Department of Energy (US DOE) and implemented by the Kentucky Research Consortium for Energy and the Environment (KRCEE) at the University of Kentucky, is charged with developing and executing a methodology that ensures that local communities are adequately involved in decisions that affect how the Superfund site will be remediated, utilized, and monitored following cessation of uranium enrichment activities at the plant. Specifically, this project is expected to ensure that future use goals for the site help advance local needs and values.

This article describes the adaptation of the authors' Structured Public Involvement, or SPI, framework for community involvement in the end-state visioning process for the PGDP facility. The SPI framework is designed to elicit community values and provide access to these as a decision support system for the development of feasible, legitimate, and durable end-state management plans. This SPI protocol is designed around community evaluation of visualizations. Key properties of visual evaluation methods for large group visualization are discussed and the Casewise Visual Evaluation method is outlined. CAVE uses a fuzzy logic based neural network modeling approach to build a knowledge base for community preferences across all feasible end-state scenarios. The potential PDGP end-state land-use properties developed from focus group work are integrated into a sample range of dynamic visualizations and the sampling protocol is described. Preliminary results will be presented at the conference.

This paper introduces the basic requirements for developing a treatability study work plan for implementation of a remediation technology at a Superfund site. Specifically, the application of nanoparticle technology for remediation of a TCE plume at the Paducah Gaseous Diffusion Plant in western Kentucky is discussed.

Nanostructured metals have become an important class of materials in the field of catalysis, optical, electronic, magnetic and biological devices due to the unique physical and chemical properties. This research deals with the synthesis of structured bimetallic nanoparticles (Fe/Pd) in membranes for the dechlorination of toxic organics from water. Nanoparticle synthesis in aqueous phase for dechlorination studies has been reported. In this study, we report a novel in-situ synthesis method of bimetallic nanoparticles embedded in polyacrylic acid (PAA) functionalized microfiltration membranes by chemical reduction of metal ions bound to the carboxylic acid groups.

Perchlorate is a principal component in many propellants and is known to inhibit hormone production in the thyroid gland down to concentrations of 1 ppb, which can be particularly harmful to children in early development and in the womb. Previous research has demonstrated the potential for rapid and complete destruction of dissolved perchlorate when exposed to doses of stabilized zero-valent iron nanoparticles (nZVI). An iron dosage will theoretically reduce Cl(VII) in perchlorate to chloride without the buildup of any intermediary chlorinated oxoanions. This study tested the efficacy of a combined regenerative and reductive process where perchlorate-loaded ion exchange resins were directly exposed to a dosage of nZVI. A quantity of the resin was added to vials containing 40 mLs of nZVI and the batch reaction proceeded for the next 24 h. In order to promote rapid regeneration of the perchlorate molecule during experimentation, salt (NaCl = 10% (w/w)) and ethanol (EtOH = (v/v)) additives were introduced into the samples. These batch kinetic tests demonstrated that at an iron dose of 1.8 g/L and at slightly elevated temperatures (~95 °C), ~98% of perchlorate was destroyed within 24 h for solutions with both salt and ethanol, and ~89% of perchlorate was destroyed for solutions with exclusively salt. This information is applicable in water treatment systems where the time required for cleaning cycles could be vastly reduced, as well as the total volume of solution water and the quantities of chemicals in the waste effluent.

The ability to detect and act upon changes in water quality is a critical component in the drive to protect our drinking water supplies from intentional or accidental contamination. The twin motivators of the terrorist threat to water along with consumer demands for safe and potable supplies has lead to a sea change in the drinking water industry. The distribution system represents the last analytical frontier in the water quality industry that has been, to date, overlooked and ignored since the inception of modern drinking water systems. The monitoring of source water and treatment plant processes has progressed to a level at which we can be confident that we are providing good quality water from the plant to the distribution system. Once the water reaches our aging distribution systems, however; our knowledge as to its continued integrity is limited by the quality and amount of available data. From a historical perspective, most monitoring in the distribution system has been relegated to the occasional snapshot provided by grab sampling for a few limited parameters or the infrequent regulatory testing required by mandates such as the Total Coliform Rule. A number of studies conducted since 9/11 have shown that bulk monitoring of basic water quality parameters has the potential to indicate the presence of many harmful agents in water at the levels of interest. (EPA, 2005; Kroll, 2006; Hall et. al., 2007). The realization of the potential of bulk parameter monitoring as a practical tool to detect terrorism related events has lead to the development of a number of sensor packages designed for deployment in the distribution system. Since 9/11, numerous communities have installed multi-parameter monitoring stations in various locations through out their distribution network as early warning systems to detect potential water security threats as well as providing operational data. These continuous on-line systems have recorded large streams of data (at some sites for a number of years) relevant to water quality in the distribution systems in which they have been deployed. These data streams are quite complex and it becomes a Herculean task to differentiate what is normal background noise and fluctuations due to normal everyday events from changes that are indicative of a deviation in water quality deserving further attention. Unless a full-time team of statisticians is to be employed to make sense of this information, the need for computer aided data interpretation becomes obvious. Intelligent algorithms are a necessary adjunct to bulk parameter monitoring if useful decision trees are to be built from this type of monitoring. Intelligent algorithms are necessary to streamline the process of data interpretation. These algorithms should be capable of detecting the subtle changes in bulk parameter readings that are indicative of an incursion into the system without burdening the operators with a constant stream of false or trivial alarms. They should also be capable of differentiating the unique pattern of responses that are elicited by different classes of agent. These differences may be enough to narrow down the cause of events and, possibly, to fingerprint the class of disturbance that caused the event. Over the past several years a number of such algorithms designed for this use have been under development by private industry, government programs, universities and national labs. The question then becomes how to evaluate the effectiveness of these potential early warning system (EWS) solutions. While a number of research studies (McKenna et al, 2006; Umberg, 2008) and programs such as the EPA's ETV program (ETV2005) have attempted to set criteria and means for evaluating such systems, many important functional criteria for such systems have been overlooked in past studies. A number of factors that are mandatory for the success of any such system are outlined below.

Increasingly stringent water use, local regulations and site approval processes are driving innovation in the application of harvesting systems tom meet site stormwater management challenges. With rainwater and site water harvesting becoming a staple in sustainable development and green building design, the opportunity to move beyond "bolt on" harvesting systems to those fully integrated with site stormwater infrastructure is being realized through the application of active and real-time control electronics, web-enabled applications and progressive design techniques. Integrating harvesting and stormwater management systems can provide both water conservation and stormwater flow mitigation in a single, streamlined system, reducing overall site stormwater control costs significantly. This paper presents design concepts, techniques and equipment requirements for incorporating this integrated approach in project water resource planning, resulting in a new tool for LID practitioners where water conservation is a key objective along with compulsory stormwater management designs. This discussion presents the new thinking on design methods for integrating harvesting into site stormwater management plans and techniques for quantifying performance and benefits, resulting in a key tool for water resource and stormwater management professionals and regulators.

Water conservation has grown in importance across North Carolina, as much of the state has recently suffered moderate to severe drought conditions. In addition to meeting water conservation needs, rainwater harvesting systems (cisterns) have an important application in low impact development (LID) as innovative stormwater management practices. A total of three cisterns were installed in each of the main physiographic regions of North Carolina: Craven County (coastal plain), Guilford County (piedmont), and Watauga County (mountain). These systems demonstrate above ground and partially buried applications. Uses for the captured stormwater include irrigating landscapes and gardens, washing vehicles, an additive for brine applied to icy streets and flushing kennels at an animal shelter. Each site is being monitored for water quantity and usage, and one system is monitored for water quality. Results will help establish the water quantity and quality benefits of rainwater harvesting systems and will influence design recommendations to be incorporated in the State of North Carolina's new Stormwater BMP Design Manual.

First flush diversion is a simple treatment method for rainwater harvesting systems in both developed and developing countries. Diverting the first flush from the main supply can improve the quality of stored water but at the cost of some loss of water supplied. This paper considers the impact of first flush removal both on the quality of the stored water and on the reliability of three rainwater harvesting systems for the 8,500 residents of Bisate Village, Rwanda. To quantify the efficacy of first flush removal, discrete samples of rainwater were collected using an easily constructed PVC bottle array. After a rain event, the samples were tested for a variety of water-quality parameters, including turbidity. The resulting plots of turbidity reduction over runoff depth follow exponential decay, as expected. Based on the water-quality data an easy-to-use recommendation for first flush operation was proposed: divert the first millimeter of runoff from a roof after three consecutive dry days. Previous researchers (Martinson and Thomas, 2005) have found that diverting the first millimeter of rain halves the contaminant load from the roof. Our similar results suggest this is a robust and broadly applicable conclusion. The recommendation was then used to evaluate the impact of first flush removal on the reliability of the system. Reliability of a rainwater harvesting system is measured by its ability to deliver the water needed by the system users. While storage-reliability-yield (SRY) behavior has been characterized for the United States by Hanson (2007), adequate precipitation data are often scarce in developing countries. To compensate for sparse rainfall records, a synthetic pseudo-daily rainfall record was generated. Using a combination of the synthetic data, the proposed management option, and the known storage and yield for three systems in Bisate Village, we calculated the impact of first flush diversion on reliability of three in-place systems. The simulations showed that for these systems the reliability would be reduced by less than 2% with diversion of the recommended first flush, while the turbidity would be decreased by 50%. Rainwater harvesting with the diversion of the first millimeter provides good quality, low-cost water in a properly sized cistern for people with few resources.

This session describes an advanced water budget analysis (WBA) model and approach for rainwater harvesting applications developed by Rainwater Recovery Inc. A case study is presented which illustrate the features of the model and the approach in general. The WBA model is a spreadsheet-based application that uses 20 or more years of the most recent climatic data local to the subject site to predict performance of rainwater harvesting systems for particular project geometries and demand patterns. Important project geometry parameters include cistern usable volume, catchment area type and areal extent. Performance is measured in terms of water savings (Utilization), runoff reduction (Efficiency), and Reliability (probability of a system meeting the total imposed water demands applied to the system on a given day). Performance for various scenarios can be analyzed next to each other in tabular and/or figure format to obtain optimum cistern size, collection area, and demands. The model is flexible enough to accommodate simple residential irrigation projects and more complex commercial or institutional projects with various collection areas, alternate sources of harvested water, and multiple types of seasonal and year-round demands. The most typical and useful application of the model is to compare performance of various cistern sizes with a fixed collection area and demand scenario. Conversely, the model can predict performance of a fixed cistern size over several collection area and demand scenarios, providing the ability to evaluate the option of connecting additional collection areas to the system in order to maximize its performance and cost-effectiveness. Many other useful statistics and graphics can be compiled from the model data such as statistics for LEED® credits or for educational purposes such as showing tank levels over a typical season, as well as quantifying water savings or reliance on a domestic back-up water supply across varying seasonal or annual weather patterns. Model output can be used to calculate system return on investment (ROI) once a harvesting system has been designed and priced by using data on water cost and use reduction and, if relevant, data on runoff volume reduction. A properly sized harvesting system can substantially reduce runoff to receiving waters or combined sewer systems, resulting in a reduction in volume and/or frequency of combined sewer overflow (CSO) events and potential savings in fees.

Rainwater harvesting (RWH) has gained increased attention in recent years as a sustainable technology capable of being a supplemental water source. Regional regression models can be used to generalize the storage yield relationship over a geographic area at a specified reliability by using certain statistics of daily rainfall as regression parameters. Such a regression is also potentially capable of analyzing changes in the storage-yield relationship due to changes in climate, so long as the changes in climate were reflected in the rainfall parameters selected for the regression. Several climate modelers have used general circulation models (GCM) to analyze potential changes to rainfall patterns many years in the future. Commonly, the gamma distribution parameters (α and β) fitted to rainfall amounts are used to investigate these changes. This study outlines a method for using these parameter projections in regional regression models to make conclusions about how rainwater harvesting will change in the future.

Although several traditional methods currently in use for rainwater harvesting satisfy the World Health Organization (WHO) requirements for water purity standards, there is still the need for the development of novel cost-effective treatment methods tailored for developing regions. Improving water quality would concomitantly improve public health in developing areas. Low-cost, high quality water is a vital resource for developing communities. In general, rainwater is relatively pure (under ideal conditions), however because rainwater could traverse paths that harbor contaminants, several forms of impurities, including: plant and animal waste, inorganic and organic particulates, moss and dissolved gases, to name a few, the harvested rainwater can be laden with impurities. The development of cost effective methods for the removal of any pollutants and bacteria is one of the goals of this study. The methods considered are low-cost alternatives that require minimum maintenance for regular household use in developing regions. Water purification schemes can use physical, chemical and biological methods, as well as radiation, for water treatment. These methods include: disinfection with chlorine and alum (which kill bacteria), filtration (including the use of micro filters), reverse osmosis, distillation, aeration, sedimentation, UV treatment, electro hydrolysis, ozonation, solar disinfection, and combinations of these strategies. Several of these treatment schemes are cost effective in developed regions and can produce water of high quality. However, the development of location-appropriate technologies for developing areas is sought. The goal is to identify and/or modify technologies as necessary, to suit local conditions --- including economic viability, the level of education of the local community, availability of materials, maintenance requirements, and other relevant factors.

Achieving sustainable performance for civil engineering infrastructure projects is a desirable goal but the tools and methods by which civil engineers can deliver technically responsive solutions in today's complex regulatory setting are still being developed. General concepts are developing for considerations of project elements that can address a broader societal need in a time of limited funding while at the same time we have significantly growing infrastructure needs. Adding social and economic considerations to a strong emphasis on environmental stewardship will be required if higher levels of higher sustainable performance are to be achieved. Transformational processes will be a necessary advance to just adding green features to traditional design approaches. ASCE has broadly embraced the need for promoting both short-term and longer-term sustainable performance for civil engineering infrastructure and is actively developing the tools which civil engineers will use to more constructively participate in the planning, design and construction support services for tomorrow's infrastructure projects.

Though it has been around for centuries, composting is becoming increasingly important today in research and in practice for its environmental benefits. Nitrogen plays a central role in the composting process and in many of the applications of compost, but despite the relevance of this topic it has not been thoroughly studied in municipal solid waste (MSW) composting. Improved management of nitrogen in compost could benefit water quality, in areas suffering from non-point nutrient runoff due to conventional fertilizers; waste management, for the organic fraction of the municipal waste stream; and agriculture, for which compost is currently too nutrient-poor to be commercially viable as fertilizer on a large scale. In this project, possible methods for engineering the MSW composting process to yield a product richer in organic nitrogen have been identified through tests in aerated, pilot-scale reactors. Compost batches run with traditional methods tended to yield a product that was low in organic nitrogen, with high nitrogen losses often observed. These results were consistent with previous research that has shown traditional MSW compost to be relatively poor for agricultural use. However, some of the process modifications were successful in conserving organic nitrogen. These included (1) the inclusion of shredded office paper as a feedstock, (2) the collection of compost leachate, and (3) the addition of strong acid or acid-loaded clay. The results of this study suggest future experiments to develop methods for producing better MSW compost.

With severe water shortage facing Indian cities and their inability to treat the sewage generated the need to optimize water use in residential areas has become an imperative. With 50% world population living in cities, and India's rapid urbanization in consonance, the security of water supply for domestic use is uncertain. Improving efficiency of city supply, modification of personal habits, use of efficient plumbing fixtures in buildings, use of treated greywater and capture and use of rainwater locally are some strategies which are being explored in response to this crisis. Amongst all these tapping rainwater has a multitude of benefits. Firstly, it can be collected and used locally if storage strategies are worked out. Being a distillate it is pure and the impurities present in rainwater are gathered on its journey to the earth's surface and thereafter to the tank. At this point in time, its quality characteristics make it suitable for bathing, washing clothes, flushing toilets, gardening, etc. If sufficient water is collected the demand for city supply of potable water could reduce dramatically. If rainwater were contained locally by directing to storage or groundwater recharge, the menace of urban flooding would be largely mitigated. Recharging will ensure improved water tables, improved quality of ground water and an assured supply for the future. However, despite the rosy picture this source is left largely un-exploited and this paper examines some of the key characteristics of Indian rainfall and their implications for using harvested rainwater as regular supplementary source of water.

As the world is facing a global challenge in declining fresh water resources and increasing demand, there are indisputable needs for conservations through sustainable strategies and practices on water use. In the power generation industry, traditionally, the majority of the consumptive water use is expended in the cooling cycle as evaporative water losses. This paper evaluates the different cooling technologies and operation strategies considered by the North Anna Power Station, who proposes to build a nuclear power generation unit located on an existing cooling reservoir, Lake Anna, to minimize water consumption and adverse impacts on lake temperature, lake levels, and downstream flows. The method of thermal and water budget analyses used to estimate water consumption and responses on the lake level and downstream flow releases are discussed. Results of the analysis indicate that, for a 1500 Megawatt nuclear unit, a hybrid, wet-dry cooling tower system in combination with changes in reservoir operation strategy could reduce long-term water consumption from about 28 cfs to less than 19 cfs as compared to a conventional once-through cooling system. These results suggest that the hybrid cooling tower technology has the potential to significantly reduce water consumption by thermoelectric power plants, thereby reducing consumptive use impacts on reservoir levels, recreational users as well as downstream flows and associated fisheries.

Researchers at Missouri University of Science &Technology have conducted studies indicating that arsenic exists in drinking water treated by ceramic pot filters (CPFs) used for point of use (POU) water filtration in developing countries. CPFs are formed from clay, sawdust, water, and colloidal silver. Van Halem et al. (2007) also showed that CPFs also leach arsenic into treated water above the World Health Organization (WHO) standard of 0.01 mg/L. The objective of this work was to field-determine the source of arsenic in CP- treated water, the form of arsenic (suspended or dissolved) in treated water, and whether arsenic concentration levels changed after prolonged use. This study focused on looking at the individual components of CPFs and to determine the source of this contamination. By isolating each component we were able to discern between those that influenced arsenic concentrations in treated water and those that did not. Field testing kits and a filtration device were used to determine the form and concentration of arsenic present in treated waters. A multi-day CPF volumetric sampling experiment was devised, where samples of new CPFs manufactured by a company in Guatemala were collected and analyzed to determine arsenic concentrations. After testing the individual components of CPFs, the data has shown that the source of arsenic contamination is the clay itself. Some clay sources have been excluded from use by the Guatemala manufacturing site because these sources were believed to contain levels of arsenic above WHO standard for arsenic exposure of 0.01 mg/L. While our testing points strongly to the likelihood that all current clay sources are contaminated with arsenic above 0.01 mg/L. The inherent variability of geologic materials makes it difficult to quantify these conclusions; it is believed that more testing may be required. This field study was conducted in and around Antigua, Guatemala where not unlike other makers of CPFs no onsite laboratory testing in existence, nor is there testing for arsenic contamination at established off site laboratories. The goal of the field testing component of this work was to prove that arsenic can be identified in the field using rather inexpensive procedures, and to lay the ground work for the design of a standard testing procedure for on-site by scientifically unskilled personnel or with help from Guatemalan University students. The ultimate goal of the this research is to develop a reliable standard testing procedures for both raw materials and finished CPF's, which would verify continued compliance/non-compliance with current WHO standards of 0.01 mg/L.

Small, rural communities typically do not have adequate water purification systems for protection from pathogens in drinking water. In Puerto Rico (PR), approximately 4% of the population does not have access to drinking water provided by the Puerto Rico Aqueduct and Sewer Authority (PRASA). These communities rely on their own water purification systems. These systems are called the Non-PRASA Systems and range from having no treatment to filtration treatment followed by disinfection. There are about 240 Non-PRASA Systems in PR. An experimental drum slow sand filtration (EDF) and chlorination system has been installed in a PR rural community where the system will be run by gravity alone (Solar power is necessary for the test system. The goal is to have a unit that is solely dependent on gravity for energy). The EDF system was initially designed and preliminarily tested at the U.S. Environmental Protection Agency (EPA) Test & Evaluation (T&E) Facility in Cincinnati, OH. The filtration system consists of three 55-gallon drums; each drum is packed with three different grades of sand. Each drum filtration unit can be backwashed independently to provide an uninterrupted filtered water supply. Chlorine is added pre and/or post filtration. Engineering operating parameters such as flow rates, filtration time, and biochemical characteristics such as turbidity, total and free residual chlorine concentrations, and indicator microorganisms have been tested. The EDF systems will be deployed to rural communities in need of reliable but low-cost/low maintenance water purification systems for sustainable water supplies and protection from water-borne pathogens.

The remediation of contaminated sediments is regularly performed through the addition of remediation amendments. The delivery of these amendments is typically executed through mechanical mixing methods, which can be devastating to the benthic communities living in these areas. This research combines the efforts of Missouri University of Science and Technology's Environmental, Mining, and Geological Engineering departments, in order to test the effects of a less invasive amendment delivery system on benthic organisms. A custom waterjet nozzle combined with a pressurized amendment vessel and a standard pressure washer are currently being investigated as a means to deliver remediation amendments into contaminated sediments. The functionality of this system and its delivery efficiency are both being assessed in other ongoing research projects. The purpose of this research was to investigate the effects that this waterjet delivery system would have on benthic organisms. The waterjet delivery system was tested on a benthic organism surrogate as a means to evaluate the newly developed delivery systems impacts on these creatures, and Styrofoam coupons were used as the surrogate. The coupons were placed in different environments and the exiting stream from the waterjet delivery system was passed over each. The variables examined in this analysis included water pressure, distance from the jet to the surrogate, depth of surrogate burial in sand and/or water, and different nozzle degree angles. For animals capable of burrowing at least an inch, like mollusks, would be safe from harm unless the waterjet was being operated within two inches of the sediment.

The Student Association for International Water Issues (SAIWI) at the University of Nevada, Reno works to develop an understanding of global water issues through community empowerment and water resource development. One of the methods used to bring clean water to developing countries is the Water for All International Manual Well Drilling method, which has many advantages for use in third world countries. This method combines manual labor with a simple mechanism to drill wells up to 100 meters. The benefits of this method include its relatively low cost, use of materials and parts that can be purchased or made in third world countries, and the ease in which the simple technology can be transferred to local communities. The most recent use of this method by SAIWI was in Nkambe, Cameroon where a well was drilled 12 meters deep, bringing clean water to the surrounding community.

Livestock operations with their manure management systems (MMSs) cause emissions of greenhouse gases (GHGs). In 2009, the USEPA promulgated 40 CFR Part 98 Subpart JJ — Manure Management rule toward reporting of these GHGs caused by the MMSs. This rule requires that selected livestock operations report CO₂e, CH₄, and N₂O GHG emissions caused by their animal production and MMSs. This paper included the details of the rule applicability and GHG emissions estimation requirements for reporting the CH₄, N₂O, and CO₂e emissions. Additionally, this paper also discusses the various reporting requirements of the rule. The owners or operators of livestock facilities with MMSs must determine the rule applicability to their facilities and confirm the reporting requirements with the USEPA.

Exposure to highway-generated air pollution is associated with elevated risk for adverse health effects. However, quantification of exposures, and hence health risk, is hampered by incomplete knowledge of the spatial and temporal variation of pollutants in near-highway residential areas. As part of a study to determine whether people who live near highways express measurably higher risk factors for cardiovascular disease, we developed a mobile laboratory to measure near-highway air pollution gradients at relatively high temporal resolution. In this paper, we report a subset of measured spatial and temporal variation of fine and ultrafine particles (7–225 nm) in the near-highway urban environment, and we evaluate the ability of the CALINE4 software package to predict ultrafine particle concentrations on an hourly timescale. CALINE4 is a line source Gaussian dispersion model intended for regulatory modeling of pollutants in areas within 400 m of highways. Fine and ultrafine particle monitoring was done within an 8,000 m² area that straddles the highway. Small-scale spatial and short-term temporal variations were found in both upwind and downwind pollutant levels. Particle number concentration generally decreased with increasing distance from I-93, though the slope of the concentration gradient varied with time of day, wind direction, and day of the week. Experimental measurements on a transect perpendicular to I-93 were compared to the results from CALINE4 for the morning of January 6, 2010. Using estimated emission factors of 9 x 10¹⁴ to 18 x 10¹⁴ particles (7–225 nm) per vehicle per mile, we achieved the best agreement between the model and the data. These calculated emission factors are consistent with values previously published in the literature. These early results suggest that a more refined model can be developed that estimates concentrations of ultrafine particles over the entire study area.

Passive treatment of landfill leachate is an enticing option for landfill sites since efficient treatment of the leachate generated can continue after the landfill closes and is no longer receiving waste (therefore not generating a profit). Treatment performance in these systems is affected by regional climate and therefore site-specific research needs to be considered for each treatment system design. This three-phase treatability study was designed to determine a pretreatment system that would minimize the size of the subsequent passive treatment system, and to evaluate various passive treatment technologies at both the bench and pilot scales. The results from this treatability study will be used to support the use of passive treatment systems for landfill leachate mitigation in North Bay, as well as serving as a template for other sites in the northern Ontario climate looking to implement passive treatment of landfill leachate.

The unsaturated soil behavior is of major significance in many of the geoenvironmental applications like deciding fate of contaminants in the subsurface, infiltration of water through caps of waste containment covers etc. The characterization of the engineering behavior of unsaturated soil is totally dependent on the soil-water characteristic curve (SWCC), which is a graphical relationship between water content (either gravimetric or volumetric) or degree of saturation and soil suction. Different SWCC models can be used to fit the experimental SWCC data. The experimental procedures adopted for determining SWCC are time consuming and cost-intensive. Consequently, recent researches have laid a major focus on the indirect estimation of SWCC. Such an estimated SWCC can be used as initial guidelines for planning important geoenvironmental projects such as waste containment facilities. As such, it is important that these SWCC models and estimation procedures are precise and suitable for different type of soils and admixtures like fly ash. With this in view, effort has been made in this paper to critically evaluate SWCC model and estimation procedure for a locally available soil and fly ash. The study indicates that the efficacy of the SWCC model was good and the estimation procedures did not give satisfactory results for the type of soil investigated in this study.

The paper discusses a comprehensive list of factors that affect water quality trading programs. The most basic elements which must be in place for a successful trading program is a firm legal backing and a commitment to making equitable decisions about all aspects of a program's design. Once these are established, the heart of a successful water quality trading program is its economic viability, which is made up by supply, demand, market size, market scale and marginal cost differences. All of the other factors both obviously economic and otherwise will somehow tie into the economic viability of the program. Even these lesser factors were found to have some hierarchies, with cost savings, risk, incentives and environmental barriers forming the second tier. Water quality trading is a tool that emerged from the movement away from command and control regulations to economic incentives.

Since the 1960's, the desalination industry has provided a sustainable and reliable source of water in arid States of the Arabian Gulf region such as Kuwait. Desalinated seawater is the primary source of drinking water in Kuwait while groundwater sources, although scarce, are typically used only for irrigation due to the extremely high salinity content. Drinking water may become contaminated during the distribution process due to the following: aging or corroded pipes, poor system integrity, pressure fluctuations from power shortages causing back siphoning, subsequent microbial or chemical infiltration, leniency in enforcing building codes, and finally aging desalination plants operating for more than 50 years. In addition, seawater pollution in Kuwait is severe due to oil spills, raw sewage, inadequately treated industrial and municipal effluent, agricultural chemicals, and indiscriminate discharge of bilge water. Water samples covering both residential buildings and educational institutions were collected from a residential area in Kuwait. In addition, water samples were collected from two desalination and distribution plants feeding the investigated residential area with drinking water. The water samples were analyzed for 104 parameters to include: bacteria, metals, inorganic chemicals, organic chemicals (pesticides, herbicides, PCB's, trihalomethanes), and endocrine disrupting chemicals. In this paper, the water samples analysis results will be presented and discussed. The paper will conclude in suggesting environmental considerations, precautions, and measures that could be implemented to secure a better water quality.

The KSTAT standards committee is in the process of issuing a standard guideline for the Geostatistical Estimation and Block-Averaging of Homogeneous and Isotropic Saturated Hydraulic Conductivity (KSTAT 3). This is the third in a series. The first two standards in the series, already published, are ASCE/EWRI Standard 50–2008 and ASCE/EWRI Standard 51–2008. The KSTAT 3 standard includes example code for performing the mathematical estimation technique put forth in the standard called easykrige. This code is written in the Matlab language and requires some familiarity with both the code and language to use. Especially difficult for those not familiar with Matlab are issues associated with data input and output. These standards are meant to be used by practicing engineers who may not be familiar with or have access to Matlab and thus may not use the example code. In this talk, we present an implementation of the example code from the KSTAT 3 standard implemented in Excel. Visual Basic and a Matlab compiler were used to develop several native Excel functions to perform kriging as defined by the Standard. This allows engineers to work with Excel, a software package they are familiar with for data input and analysis, while using the approaches promulgated by the Standards committee. We also present a short case study using the code.

The purpose of this paper is to provide the necessary information to understand the theory of the Particle Tracking Model (IGSM_PT). IGSM_PT is a particle tracking model that was developed to compute two-dimensional flow paths using output from steady-state or transient (as small as daily simulation time steps) ground-water flow simulations by Integrated Groundwater and Surface Water Model (IGSM), a finite element flow model (Taghavi et al., 2003). Once the head solutions from IGSM have been obtained at every node, the principal velocity components for each element can be computed using the finite element shape functions and Darcy's Law. In order to compute the path lines, IGSM_PT uses constant velocity throughout the element to compute particle paths. IGSM_PT uses a technique (in-element particle tracking) that traces particles on an element-by-element basis. Given a velocity field, a particle is traced element by element until either a boundary or an internal sink/source is encountered, or the available time is completely consumed. The paper also presents verification of the model with 2 example cases. First, the comparison of the model results with a simple example with an analytical solution. The second example is a moderately complex sample problem from the MODPATH User Manual, which is used to verify IGSM_PT and compare its results with MODPATH.

The present paper develops a new theory of three dimensional land movement, including vertical (subsidence) and radial (fissures) displacement, within an aquifer system in response to depressurization caused by ground water withdrawal. The new theory is derived from the first principles of physics (conservation of mass and linear momentum), secondary laws (the Darcy-Gersevanov law of relative flow, the constitutive law of poroelasticity and the equation of state for water), and the appropriate flow relation. Unlike previous theory, in the new theory, shear and volume deformation are decoupled and presented in equilibrium and non-equilibrium equations and are also integrated into one governing equation. When compared to the traditional theory, the new theory expresses itself in terms of aquifer's displacement field. There is no additional need to couple two fields as has been done previously, (e.g., Biot's theory). In particular, the new theory compares well to Biot's traditional consolidation theory that couples aquifer's displacement and changes in pore-water pressure (or hydraulic head). As a result, strategies for analytic and numerical modeling and computation can be simplified in the phase of finding a solution. The substantial mechanistic difference between the present depressurizing model and the traditional loading model for soil consolidation is discussed.

Long-term monitoring plans for groundwater remedial systems use monitored natural attenuation and risk-based goals to reduce the high cost of conventional remediation such as pump-and-treat. Several computer models that evaluate the condition of contaminated plumes and offer information on optimizing the testing plan rely on reasonably organized and accurate data. Uncertainty is interjected from testing methods, use of hydrogeological models used to predict hydraulics of a plume, and the limitations of the computer model. The "user friendly" optimization model MAROS, Version 2.2, is offered by the Air Force Center for Environmental Excellence. This model creates temporal and spatial overviews of the plume with Mann-Kendall, linear regression, and moment analysis using Delaunay triangulation. It further predicts deletion or addition of wells, sufficiency of the wells, and the degree of degradation of the plumes. One specific case study evaluated the condition of existing TCE is shallow aquifer plumes. Initial data was analyzed regarding issues of uncertainty, reliability, frequency of collection, and variations in the overview of the plume conditions. Data that is too random and gapping in time results in inability to analyze plume and varying TCE degrading concentrations. MAROS is considered a generalized management predictability tool to optimize and lower the cost of plume monitoring while meeting appropriate risk levels; it too must rely on certain parameters of data collection and management to provide results that are meaningful and useful.

In this paper we describe a GIS-based system for automated well permitting. The system involves the integration of a calibrated MODFLOW groundwater model into an ArcGIS geodatabase using the Simulation feature dataset in the Arc Hydro Groundwater data model. The model is then used as a baseline for the analysis of candidate wells. Each candidate well is added to the model and the model is run to determine the impact of the well on streamflow, drawdown, etc. The entire process is implemented using a series of connected, low-level geoprocessing tools resulting in a simple automated process. The automation serves to reduce error and increase efficiency. The outputs include tables and GIS maps. The process, evaluation criteria, and products can be customized on an agency-by-agency basis. We illustrate the process using case studies from Virginia and Florida.

Literature provides a good knowledge base to understand geothermal heat pumps. Therein two principle types are defined: Ground-coupled heat pumps and groundwater heat pumps (GWHP). In this paper small-scale GWHP typically used for heating of single family homes are investigated. One important parameter to ensure optimal performance of GWHPs is the spacing of production well (PW) and injection well (IW) because wrong design leads to hydraulic and thermal breakthrough. Due to a general insufficient knowledge about the required spacing of PW and IW regarding thermal breakthrough the aim of this study is to develop an empirical equation for spacing design. Additionally three dimensional tracer and temperature maps as well as a sensitivity analysis of varying parameters (flow rate, injection temperature, horizontal/vertical conductivity, longitudinal dispersion and base flow gradient) are provided in this article. A comparison of the equation with official guidelines shows that for single family homes the horizontal spacing can be reduced up to 90%.

This paper reviews commonly used statistical methods, and demonstrates their applications in ground water. In today's world, statistical methods have been frequently used in almost all research and practice areas. The statistical results (for example, mean, standard deviation, percentiles, correlation, p-valve, etc) can help researchers and engineers better understand data features and make more sound decisions. Ground water, as one of three water forms on earth, represents 99 percent of the earth's available fresh water. In the U.S., about 90 percent of fresh water supply is from ground water, which accounts for about 80 billion gallons of ground water withdrawal. With no doubts, ground water is extremely important to human beings and surrounding environment. These two important specialties are combined and discussed in this paper. Firstly, commonly used statistical methods are reviewed including mean, standard deviation, Monte Carlo method, time series models, etc. Furthermore, practical applications of these statistical methods are conducted in ground water hydraulics, aquifers, contaminant transport, and monitoring. In conclusion, statistical applications in ground water can assist researchers and engineers to effectively select statistical methods and accurately understand final statistical results to make and justify their critical decisions and conclusions.

This research attempts to develop a lab module using a virtual 3D modeling approach. Developed 3D model is capable of providing flexibilities to the students to walk through the groundwater system and visualize the contaminated plume movement with respect to time & space. It also facilitates the students to understand the effectiveness of different remedial alternatives to the system. The study considers a quasi three dimensional model for 2000 ft x 3000 ft area with 8 layers representing different soil formation. The model was simulated for 10 years and the model results were captured for each cell for every 50 days time step. Then work virtual reality based three dimensional visualization modules were prepared for understanding the complex process of contaminant movement with the ground water.

Remediation of contaminated groundwater may involve the injection of one or more reactants into the aquifer to stimulate degradation of contaminants, coupled with removal of water from an extraction well to increase circulation. Ideally, the reactants should be mixed throughout the contaminated area to optimize the reaction rate. However, due to the laminar flows characteristic in porous media, mixing in groundwater is an inherently slow process, governed by molecular diffusion. In particular, laminar groundwater flow is an example of potential flow, which implies that it is irrotational. In contrast, mixing occurs more readily in rotational flows, such as turbulent flow in streams. In these fields, a material line will be stretched and folded within the domain due to transient vortices. We investigate the possibility of applying this paradigm in aquifers. Specifically, we explore how well injection and extraction schemes can be engineered to create transient flows that lead to stretching and folding, and therefore mixing, within an aquifer.

Groundwater management using optimization techniques has been studied extensively for some time. Tools have been developed, tested, and applied as demonstration projects. A number of these demonstrations have been successful, and yet they are still viewed somewhat as research projects with limited practical applicability to industry or the universe of possible applications. At the same time, a paradigm shift is taking place within the United States and world where "going green" has become a part of the philosophy and business plan of many companies. A component of the green movement is conservation and sustainability of natural resources, of which groundwater is a major component. Optimization is clearly an available tool that can be used to promote conservation and maintain sustainability of groundwater resources, and yet, it is not used extensively or to its fullest effectiveness. This paper provides the perspective of a groundwater professional in the consulting industry on the limited use of optimization techniques and offers suggestions for increasing its use.

Groundwater systems are complex, exhibiting significant heterogeneity across multiple scales, multiple interacting processes, and nonlinear behaviors. Groundwater systems are also open, often with poorly defined boundaries and time-dependent, uncertain boundary forcings (e.g., recharge). As a consequence, a groundwater model cannot be expected to precisely reflect the system it represents and the model results are uncertain quantities. The dominant language of uncertainty is probability and the majority of research in the treatment of uncertainty in groundwater modeling has been directed at developing and improving probabilistic methods for these models. One area of recent research has been methods for assessing the impact of model uncertainty in groundwater analyses. This line of research is part of a long-term trend of increasing appreciation for the importance of providing estimates of uncertainty in groundwater model outputs. The research was motivated by observations of nonuniqueness in model parameterizations, the sensitivity of groundwater model output to model structural choices, and a history of practice that established the importance of iterative improvement in the conceptual basis of groundwater models. Among the methods proposed for assessing model uncertainty, we discuss Bayesian model averaging, it's theoretical basis and research development. We outline critical arguments and discuss alternative approaches. Finally, we briefly describe a regulatory application of groundwater modeling that used Bayesian model averaging concepts to resolve a key conceptual model uncertainty.

The purpose of this paper is to present an industry perspective on the calibration of groundwater flow models in view of the limitations imposed by budget and schedule constraints in engineering practice, considering also planning issues related to the execution of different phases of engineering projects. The majority of groundwater modeling applications in engineering practice fall in one of two categories, models that attempt to explain past behavior in order to design the remediation of a known existing problem, and models for sites of new facilities aimed at predicting changes in the groundwater regime due to the construction of new structures. A typical problem of the first category is the analysis of the migration of contaminant plumes originating from historic sources and the design of groundwater remediation solutions. The second category often includes large new industrial structures, such as new powerplants, where models are used to estimate hydrostatic loads used in the design, or to assess the risk from potential accidental releases of toxic or radioactive liquids that may enter the groundwater system during the life of the facility. Model calibration depends on the number and quality of available data. In engineering practice, a typical site investigation study includes the installation of several monitoring wells, aquifer tests and groundwater quality sampling. For studies in support of the construction of new facilities piezometric levels and water quality are typically monitored over a period of one to two years. Groundwater contamination studies may have much longer records. Aquifer testing is in most cases limited to slug tests. At sites where pumping tests are conducted, they are often limited to one or two tests. At construction sites, other available data often include data from borings drilled as part of geotechnical investigations. Sometimes data from geophysical investigations and laboratory analyses for the distribution coefficients of specific chemical compounds are also available. The starting point for any model is a credible conceptual model of the physical system. Conceptual groundwater models are constructed based on the understanding of the site geology and the interpretation of all available data. Because of the many uncertainties in this process, plausible alternative conceptual models are often considered.

Gravity-fed distribution systems are commonly constructed around the world for provision of drinking water from natural springs. Although they are considered to be an appropriate technology because of simple maintenance requirements and lack of mechanical parts, the sustainability of these sources depends on whether spring discharge can accommodate water needs under present and future conditions. We present results from a study conducted in the Alto Beni region of Bolivia, where communities depend on gravity-fed distribution systems for their drinking water needs. The region is rapidly converting from forest to agriculture. Communities relying on these systems perceive a decrease in spring discharge, and suspect this change is due to increased agricultural use of land in the region. A daily water balance model is used to predict recharge rates, with recharge estimated using the NRCS curve number method. The NRCS curve number model is calibrated against daily stream discharge measurements to obtain estimates of curve numbers for orchards and forests. The recharge is then modeled under scenarios of changes in precipitation and temperature due to global warming and under predicted expansion of agricultural area. Recharge is predicted to decrease in all cases, however the impacts from climate change are larger than those from agricultural expansion.

A global, coastal database was investigated in a model typology based on a simple, unconfined, coastal aquifer to begin to explore the impacts of climate change on saline intrusion. A basic database provided temperature, precipitation, population density and evapotranspiration in mm/yr. Because evapotranspiration is not forecast, as a rule, in climate models the evapotranspiration value is predicted from a linear correlation with the temperature data. A "freshwater scaling parameter" was calculated as the average annual precipitation minus the predicted evapotranspiration minus the product of the population density times the national per capita water use. A few parameters provide good resolution of types of coastal hydrology as a basis for forecasts. When fully developed, the algorithm is intended to be incorporated into the Dynamic Interactive Vulnerability Assessment (DIVA) model presently to investigate salt water intrusion length in estuaries, beach erosion, land-loss and other parameters.

This research focuses in understanding the interaction between climate, groundwater and surface water over the Southeastern US. For this purpose, we consider observed streamflow, precipitation, temperature and groundwater levels from twenty basins from the USGS climate-groundwater network. Seasonality analyses on the four variables indicate both high and low periods of activity for each variable. Singular spectrum analyses on all the four variables indicate that groundwater is the most dominant component in explaining the first component. Relating eigen values with drainage area show that large basins exhibit increased role for groundwater. Analyses on relating precipitation forecasts and sea surface temperature conditions show that there is a potential in predicting groundwater availability purely based on climate information.

This article discusses rainwater harvesting as a means of supplementing other water sources. We will focus on efforts in a lakeside village in Kerala, India where Rainwater for Humanity leads a collaborative project joining local volunteers, with students and faculty from Mahatma Gandhi University, Brown University, and the Rhode Island School of Design to design, construct, and monitor several single and multi-family systems. Although the area has extensive waterways and surface water, contamination from untreated sewage and agricultural runoff renders most of the resource unfit for drinking. In addition to the technical problems presented by the environment (high water table, unstable soil, variable weather conditions), multi-family systems present significant social challenges as well. An equitable distribution of both the resource and the labor necessary to maintain the system, are challenging to negotiate. Work with a local women's group has the potential to solve some of these issues. The design effort is carried out both in Providence, RI and on site in India. This allows back and forth learning between the two institutions of higher education, local groups, and umbrella non-profit to evolve, but complicates implementation.

Jordan is considered to be one of the 10 poorest countries worldwide in water resources, and has a population growth rate of about 2.9% (1998–2002), the 9th highest in the world. The available renewable water resources are dropping drastically to an annual per capita share of 160 m³ in recent years. Within Jordan, the Zarqa River is the third largest river in terms of its annual discharge. The river is heavily contaminated with treated domestic and industrial wastewater principally from the city of Amman, but still serves as a major source for irrigation water. We consider riverbank filtration (RBF) an appropriate technology that efficiently and dependably procure quality water from Zarqa River thus making a contribution to protect Jordan's remaining surface and ground water resources. Since 2006, a RBF well field has been installed. Six wells were drilled at various distances from the river. Salt tracers have been released to the hyporheic zone and were detected in a RBF well during subsequent pumping. From the tracer test data, approximated travel times have been established and first observations regarding the removal of microbial matter have been obtained. The data indicate rapid travel times and 2 to 3 log units of removal even over a very short distance from the river (< 10 m). Additional tests are planned to further investigate the performance of the RBF system. However, it is already clear that the RBF has significantly improved the water quality and local farmers have begun using our RBF water for agricultural purposes.

At certain sites in northern India, the efficacy of riverbank filtration (RBF) systems was tested. The first RBF site is located near Haridwar at the foothills of the Himalaya. Because at times a great numbers of pilgrims visit this site, the water demand is highly variable. The RBF is surrounded by the river Ganges and two canals originating from the river. Recently, the upstream reaches have witnessed increased sediment load because of deforestation and construction activities related to hydropower plants and residences. In view of these changes, measurements of water quality in river water and bank filtrate are performed for one year to study the possible effects on the RBF system. A simple model is developed to relate influent (source water) and filtrate concentration. The model indicates that the filtration coefficient is linearly related to the natural logarithm of the influent concentration and other water quality parameters. The second site is located near Muzzafar Nagar, a city 100 km downstream of Haridwar. The river Kali receives a huge input of non-point pollution while flowing through the city and dissolved oxygen levels in this river are very low (many a times at zero level). For a period of six months water quality measurements were conducted in the river and in water abstracted from nearby wells. The data analysis focuses on the removal of different types of impurities including E. Coli and a model of the filtration coefficient as a function of influent concentration is also developed. The results from both RBF sites indicate that there is a lot to be done in refining the existing practices. For example, at the first site, an optimum abstraction of filtrate water and regulated release pattern of source water have to be implemented to achieve better filtrate quality. Further, RBF is a useful option to abstract water from the banks of a very polluted river, such as Kali, as evident from second site investigations. Overall, RBF promises to be a very cost effective approach of abstracting water in developing countries.

For most rural areas, rain water harvesting is typically conducted to provide potable water to house-holds or local point-of-use areas. However, in Abheypur India, rain water is also being collected to recharge the groundwater. This broad awareness to the lowering of the groundwater table demonstrates a cultural sensitivity and the need for sustainable solutions; however, if well head protection is being compromised, it also leads to potential water quality issues and does not effectively recharge the aquifer.

A source of fresh potable groundwater on an isolated island is the most valuable of resources. Yet it is very limited and also the most vulnerable to contamination and destruction by mankind. The availability of fresh water on an island is directly related to the island size in conjunction with the geologic and climatic conditions. Islands can be generally classified as low islands or high islands. Most low islands are composed of relatively permeable sand or corals into which precipitation readily infiltrates; there are commonly no free flowing surface streams. In contrast, high islands are typically composed of volcanic rock with varying degrees of permeability, but tending to be relatively dense with only secondary fracture permeability; island mountains in oceanic environments also create their own high altitude climate, frequently with a wet side with running streams, and a much drier side from a wind generated "rain shadow" effect. The high islands usually offer more sustainable water development possibilities In oceanic islands, the fresh groundwater within the island is often in a unique balance with the sea water, known as the Ghyben-Herzberg principle. This is based on the principle that fresh water, being less dense than salt water, will tend to float in a lens configuration on the salt water that lies at some depth under islands. The most effective groundwater development is a "skimming" process, by shallow wide diameter wells or infiltration galleries. Since the groundwater lies at shallow depth in a low-lying island, it is highly susceptible to surface contamination from many sources. A well recharge protection zone free of contaminating disposals of any kind must be established and the well itself must be sealed and protected from direct outside contaminant sources.

This work investigates the efficacy of ceramic filters treated with silver nanoparticles as a point-of-use water treatment intervention in two developing-world communities: San Mateo Ixtatan, Guatemala and Limpopo Province, S. Africa. In San Mateo Ixtatan, filter interventions were designed to evaluate the technological performance and social acceptance of the filter in 60 households. In Limpopo Province, an ongoing intervention is being studied for HIV-positive individuals with the goal of also evaluating health effects of the filters. This latter study recruited 66 individuals with about half receiving filters and the other half serving as a control group. Data for Guatemala show significant social acceptance of the filter and initial coliform bacteria and E. coli removal rates greater than 97%. Early data for the S. Africa study demonstrate a 69% reduction in the number of days of diarrhea per month in patients who received the filters compared to those who did not.

Nitrogen leaching is a serious water quality concern for irrigated farmlands. This concern is likely to be alleviated by reconstructing water-saving projects as well as implementing water-saving irrigation practices. The objective of this study was to evaluate effects of water-saving irrigation practices on nitrogen leaching pollution and water quality in regional farmland groundwater. The evaluation was conducted in the Jiefangzha Irrigation Scheme of Hetao Irrigation District (HID) in the Inner Mongolia Autonomous Region of China. For the growing-season months of March, May, July, and September in the years 2003 (before the water-saving irrigation practices being implemented) and 2008 (after the water-saving irrigation practices being implemented), the nitrate-nitrogen contents and other water chemistry parameters (e.g., pH, TDS) were determined by taking and analyzing groundwater samples fetched from a number of wells across the scheme. The analysis compared changes between these two experiment years of the irrigation volumes, the depths to water table, and the groundwater nitrate-nitrogen contents and water quality. Using the inverse-distance weighted (IDW) interpolation method and the measured data in 27 wells, this study generated maps illustrating changes of the temporal trends and spatial patterns as a result of implementing the water-saving irrigation practices. The results indicated that prior to the first irrigations in March, the areas with the nitrate-nitrogen concentrations higher than 10 mg/L (i.e., the national drinking water standard ) accounted for 9.95% and 5.22% in size of the irrigation scheme in 2003 and 2008, respectively, while the annual average nitrate-nitrogen concentrations higher than 10 mg/L accounted for 9.02 and 5.20%. These area reductions can be attributed to the water-saving irrigation practices implemented between these two years. At the same time, the groundwater quality also has been improved because the TSD was lowered by 21.4% from 2003 to 2008. The noticeable effects include the: 1) lowered nitrate-nitrogen leaching by reducing irrigation volume; 2) reduced irrigation quote in fall; 3) decreased water table; and 4) improved groundwater quality. A reasonable generalization of these results is that the water-saving irrigation practices will be beneficial to the ongoing efforts to control non-point source pollution and improve water quality across the HID.

Mathematical based decision support for operative scheduling in water supply systems is highly desirable but leads very often to very difficult optimization problems. In this paper we propose a nonlinear programming approach that yields practically satisfactory operating schedules in acceptable computing time even for large system with several pumps. Based on a carefully designed software using Scatter Search, Tabu and Neural Networks in hybrid optimization algorithms, this approach employs a special initialization strategy for convergence acceleration, special minimum up and down time constraints together with pump aggregation to handle switching decisions, techniques for further speed-up. Results for selected application scenarios at Bouregreg water production system in Morocco demonstrate the high performance of the approach.

Thermal testing is an objective design measure for geothermal wells. Thermal testing is performed by heating water pumped from a standing column well and returning it to the annular space of the well, while monitoring the rise in water T over the duration of the test. The average water T is plotted against the log of time to derive three key thermal characteristics of well bore formation; effective thermal conductivity, thermal diffusivity, and thermal decay time for thermal relaxation. The effective thermal conductivity is the most important thermal measure since it allows one to specify a well field design to meet a specified heating and cooling loading. In Spring of 2009 a 535' pilot standing column well (SCW) was tested to determine thermal characteristics of the well bore and its surrounding gneiss formation. While gneiss typically offers a thermal conductivity below 3.5 W/m°K (2 BTUH/ft°F), the "effective" thermal conductivity was shown to be considerably higher, viz. 5.35 W/m°K (3.1 BTUH/ft°F). At 0.18 m²/day (2.1 sqf/day), the thermal diffusivity, α, was also twice as high as expected. The interpretation of these results and the impact on geothermal HVAC design is discussed herein.

This paper describes some of the findings and outcomes of a nationally prominent wetlands restoration program which is unusual in scale (55,000 acres) and hydraulic complexity. Ecosystems prevailing in the area of the Picayune Strand Restoration Project (PSRP) in southwest Florida had been profoundly impacted by the installation of drainage canals designed to lower water tables on a regional scale and thereby create large tracts of developable land. This development effort had eliminated the original mix of natural overland flow and amorphous flowways, replacing it with a highly structured network of canals, roads and associated ditches or other hydraulic features. Present plans are to recover the natural condition by eliminating the canal system over an area of some 55,000 acres. A constraint to these plans was thateighboring areas, including agriculture, residential, business, transportation and natural systems areas, were not to be adversely impacted. In particular, backwater flooding of upstream developed areas which might result from canal removal downstream was to be avoided. A substantial design analysis was performed to establish how best to maintain some form of positive drainage in a way that does not increase the potential for flooding outside the project area. It was decided that upstream flows would be captured and discharged through several large (several thousand cfs) pumps to lateral spreading canals that approximate predeveloped overland flow conditions. The design options to accomplish this basic scheme were numerous and involved a variety of candidate configurations. Ultimately, plugging the original canals at intervals was found to be hydraulically efficient and cost effective compared to total filling. In the long term, natural process will complete the process of infilling the canal drainage network. This paper discusses the analyses that were undertaken to establish the preferred restoration plan, the results of the project in its present partially complete state, comparisons of measured groundwater responses in the pilot restoration area to simulated responses and lessons learned as construction and monitoring has been pursued. In particular, the concerns raised by observed plugging practices are noted, and lessons learned for this type of large scale rehabilitation are provided. Suggestions are made regarding preferred practice, and areas meriting further research are identified.

Natural attenuation has the potential to effectively remediate TCE in bedrock aquifers, albeit slowly, with in situ half-lives that can range from 80 to 800 days if dehalogenating bacteria are present. Nutrient distribution, mineral speciation, habitat availability and seasonal geochemical cycling may limit microbial colonization. To demonstrate natural attenuation in the zone between plume and receptor, these factors must be addressed along the groundwater flow pathway. In this paper, a method is developed to assess natural attenuation of chlorinated organic compounds with greater statistical confidence. Recent developments in microcosm methods for the evaluation of bedrock aquifers are employed for more statistically significant laboratory evaluations, and then comparisons made of field measures for model verification. Analysis of data from a bedrock aquifer consisting of meta-siltstone and meta-sandstone in Southeast New Hampshire is used for illustration, complete with cost evaluation and comparison of error probability versus expended cost.

To effectively design a geothermal standing column well (SCW) field and energy system it is important to first install and test a pilot well. The data collected from the pilot well support the design of the SCW field in several ways. Pre-drilling exploration can reveal bedrock types, structure, and characteristics, aquifer yield, and groundwater quality/characteristics of the environment into which the geothermal is intended to be installed. This determines whether the site is suitable from a cost-effective perspective. For example, certain rock types are more effective at providing thermal transfer; while estimated groundwater yield and hydraulic conductivity determine viability of bleed and alternate groundwater uses. Geochemical characteristics are used in the evaluation of encrustation, scaling or bio-fouling of heat ground source heat pump equipment. The pilot test also provides information for full scale-up SCW design including optimal SCW depth, and the number of wells required. Therefore, research, pilot testing, and collection of scientific data prior to completing a SCW design is critical to avoiding costly mistakes.

Borehole geophysical techniques were used to characterize the subsurface conditions and contribute to the design of a geothermal well in crystalline bedrock in a southern New Hampshire location. Multiple wireline probes were run to help determine lithology, porosity, vertical fluid flow rate, water quality, engineering rock properties, borehole deviation, as well as the orientation of fractures. To achieve these objectives, standard logs and borehole images were recorded using natural gamma, resistivity, density, caliper, full waveform sonic, water quality, heat pulse flowmeter, acoustic televiewer and optical televiewer probes. The results were used to characterize the subsurface and contribute to the design of a geothermal well. The results indicate that the occurrence and direction of ground water flow are controlled by open fractures. The depth, orientation, and aperture of fractures were measured using optical and acoustic televiewers. Deflections in fluid temperature and water quality curves interpreted in conjunction with heat pulse flow measurements indicate which fractures are producing and which are receiving water. Relative fracture transmissivity was also estimated using heat pulse flowmeter measurements made during static and pumping conditions.

Phosphorus (P) impairs reservoir water quality and managers impose limits on external P loading to address this problem. Even with P reductions, restoration has taken longer than expected at many reservoirs. Researchers attribute this to internal P sources, such as the interactions between the reservoir water column and sediment pore water. Subsurface nutrients and groundwater/surface water interactions seem to dominate many of these reservoirs. Data sets to characterize sediment P distribution are rare, but critical, as studies show that P types and amounts vary spatially. Deer Creek Reservoir (DCR), Utah exhibits ongoing degradation even after significant reduction in external P loading. A recent DCR construction drawdown provided a unique opportunity to study delta sediments and determine the potential amounts, geochemical sources, and spatial distribution of P. Traditional reservoir studies are limited by the ability to take large numbers of core samples. We were able to obtain samples and data in higher resolution than in previous studies. We took 91 sediment samples in six transects to define the spatial distribution and geochemical form of P over an approximate 750,000 m² (185 acre) area. In addition to surface samples, at selected sites we took samples to characterize vertical P distribution. We analyzed all samples for water soluble P, and 19 samples for four other P forms. Water soluble P ranged from 2.28E-03 to 9.81E-03, KCl-P from 2.53E-03 to 1.10E-02, NaOH-P from 5.30E-02 to 4.60E-01, HCl-P from 1.28E-01 to 1.34E+00, and organic (residual) P from 8.23E-01 to 3.23E+00 mg⋅g^–1. Initial geostatistical analysis indicated spatial trends in the P distribution that follow expected sediment distribution patterns.

In August 2009, the Federal Advisory Committee on Water Information's (ACWI) Subcommittee on Ground Water (SOGW) published a framework for implementation of a nationwide, long-term groundwater quantity and quality monitoring network. The SOGW is continuing to play a key role in leading these efforts, with the ASCE representative to ACWI (this paper's author) serving as co-chair of the SOGW. To accomplish its current goals, the SOGW realized it must address several issues regarding network design, management, and operations. The primary vehicle for this is a tried-and-true engineering approach: pilot testing. Therefore, this paper discusses the foundation of the National Ground Water Monitoring Network, and the pilot-testing that started in early 2010 and which is expected to make significant progress by May. The 2010 Congress and Symposium represent an important opportunity to inform EWRI members, and to learn from them as well as from other participating disciplines, who are involved in and who benefit from networks such as the one being implemented.

Lots of uncertainty exists in the groundwater modeling, e.g. hydraulic conductivity, measurement variance and the model structure error. Monte Carlo simulation of flow model allows the input uncertainty onto the model predictions of concentration measurements at monitoring sites. Bayesian approach provides the advantage to update estimation. This work proposes a dynamic framework in contamination source identification of groundwater. Markov Chain Monte Carlo(MCMC) is being applied to infer the possible location and magnitude of contamination source. Unlike other inverse-problem approach to provide single but maybe untrue solution, the MCMC algorithm provides distribution over estimated parameters.

Wavelet analysis involves an integral transform of, for example, a hydraulic conductivity field, using a wavelet as the kernel of the transform. A wavelet is a function that is non-zero only over a finite region; therefore the wavelet transform analyzes only a subset of the data set. The wavelet is shifted to analyze different subsets of the data set, and it is scaled to analyze different scales of the data set. In this study wavelet analysis is used to investigate the relationship between the spatial variability of hydraulic conductivity and the spatial variability of hydraulic head in a one-dimensional confined aquifer. We perform wavelet analysis and calculate the local wavelet energy spectrum (LWES), which provides information about dominant length scales at each position in the domain. We generate sets of bounded, one- dimensional, stationary hydraulic conductivity fields with known statistical properties and we run numerical flow simulations, with constant head boundaries, using these fields. We use wavelet analysis to analyze the dominant scales in both the hydraulic conductivity fields and resulting non-stationary head fields, and we explore the relationships between hydrogeologic parameters, dominant scales in the hydraulic conductivity fields and dominant scales in the head fields.

This paper will present a national overview of source water assessment and protection in several states and an in-depth examination of Source Water Assessment and Protection programs in selected states. The paper will focus primarily on how the programs are implemented and will discuss how the program results are provided to the community. The paper will address both assessment and protection, and will evaluate which states have voluntary versus mandatory protection programs. Based on the state-to-state comparisons, the paper will provide observations regarding effective strategies for implementation of SWAP programs.

The spreading of chlorinated volatile organic compounds (CVOCs) in the subsurface depends on multiple transport mechanisms and reaction processes, such as advection, dispersion, atmospheric release and chemical-physical-biological reactions. The transport of contaminants can occur in both water and gas phases. Especially, the movement of contaminants in gas phase can be faster than that in water phase due to the high dispersivity of chemicals in the gas phase. The vaporized CVOCs can be released into the atmosphere through the ground surface, resulting in reduction of total mass and concentration of the contaminants in the subsurface. This study investigates the impacts of the atmospheric chemical releases and ground-surface conditions on CVOCs' fate and plume development in the subsurface. Tetrachloroethylene is as the primary contaminant, and its biodegradation byproducts are also considered.

The Texas Source Water Assessment and Protection (SWAP) Program was promulgated as part of amendments to the 1996 Safe Drinking Water Act and consists of two fundamental aspects: Assessment and Protection. Administered under the Texas Commission on Environmental Quality (TCEQ), compliance with the State of Texas Source Water Protection (SWP) program is voluntary and thus taking action on the information contained in the assessments has been encouraged but ultimately left to the discretion of the water system. The objective of this paper is to present an overview of recent SWP implementation efforts in Texas public groundwater systems. Since 2007, TCEQ and its subcontractor CDM have implemented SWP activities for selected project areas. The individual water systems have been selected because they: (1) are highly susceptible, as determined through the initial source water assessment; (2) lack substantial source water protection implementation; and (3) are small water systems. Required elements of source water protection programs include the delineation of the wellhead protection area, development of a contaminant inventory, evaluation of appropriate best management practices (BMPs), preparation of a contingency plan and preparation of a final source water protection report. A streamlined process was developed and employed by CDM to implement the required elements for multiple supply systems concurrently and will be presented. Components of the process include the use of development and use of standardized forms, and report templates, and implementation of a BMP evaluation database tool. In addition, a source water assessment and protection "brand" was developed to facilitate recognition and communication of a consistent message as part of a comprehensive public education and outreach program. These processes, coupled with effective data analysis and proactive consensus building, have yielded successful SWP implementation. The success of current efforts in the State of Texas will be discussed. Voluntary involvement in the project has been high for the identified systems. A total of seven systems have successfully completed the SWP process, protecting drinking water for 18,000 customers. Of these seven systems, three have completed outreach events focused on SWP with the assistance of TCEQ and several have begun the process of BMP implementation. TCEQ's goal for this project is substantial implementation of SWP activities and the public groundwater systems identified for this project appear to be well on their way to achieving those goals.

On-site wastewater (septic) systems have often been implicated as a source of high nitrogen content in groundwater in Eastern North Carolina. At the national level, the Centers for Disease Control and Prevention (CDC) pointed out the need for enhancing the knowledge of septic systems performance. This paper is part of a study that was designed to address that need. The objectives of this work were to determine if electrical resistivity mapping is an applicable technique for characterizing septic system effluent plumes in sandy soils and to investigate the links between septic system discharge, groundwater quality, and potential contributions to surface waters. Electrical resistivity surveys were completed on two sites that use septic systems in Washington, North Carolina. Plumes of low resistivity groundwater were identified at both sites. Orientation of the plumes matched closely with the direction of groundwater flow away from the septic systems as indicated by groundwater level data from piezometers. Preliminary data of samples taken from each septic tank showed total nitrogen concentrations between 46 and 48 mg/l, mostly in the forms of organic nitrogen and ammonium nitrogen (NH₄-N). Also, preliminary data showed higher concentrations of nitrate nitrogen (NO₃-N) and organic nitrogen in shallow groundwater samples adjacent to septic systems than in background samples. While dissolved nitrogen concentrations typically decreased as the plumes moved further away from the systems, elevated nitrogen concentrations were seen close to the estuary at one site. Future work will include septic tank and groundwater N-isotope sampling and installation of YSI sondes (automated NO₃-N and NH₄-N sensors), to gain more information on N-processing and the fate and transport of dissolved nitrogen in shallow coastal aquifers.

The Ozark region of eastern Oklahoma is characterized by limestone and sandstone plateaus partitioned by steep-sided stream valleys and occupied by clear, gravel-bed streams. Alluvial floodplain soils are generally cherty with high hydraulic conductivities. Many areas have alluvial floodplains consisting of a mantle of alluvial soils overlying thick subsoil primarily consisting of gravel. Previous work at a site in eastern Oklahoma found preferential flow of a conservative tracer within the gravel subsoil with an estimated hydraulic conductivity of 140 to 230 m/d. Multi-electrode electrical resistivity imaging (ERI) was used as a non-invasive method to determine the nature and extent of the preferential flow path (PFP). The ERI two-dimensional profile found a highly resistive layer in the area of the PFP. The range of resistance for this area was similar to the resistance found in an ERI survey from the surface of a nearby gravel bar, which strongly suggested that the PFP consists of clean, coarse gravel. This study attempted to determine whether PFPs exist at two other alluvial floodplain sites in the Ozarks with differing catchment areas. Since the factors controlling resistivity are similar to the factors controlling hydraulic conductivity, an association between the two was expected. Borehole permeameter tests, using a system specifically designed for gravelly soils, were used to estimate saturated hydraulic conductivity. An equation was developed between the point-measured hydraulic conductivity and larger-scale electrical resistivity mapping. Limitations in current analytical solutions prevented the estimation of hydraulic conductivity for all tests, primarily due to the rates that were induced on the gravel subsoils.

Groundwater contamination due to the nutrients from a septic tank system is a vital concern in environmental health. Active OSTDS also know as on-site wastewater treatment is dependent on the use of pump to sustain the aerobic condition in the process and promote the nitrification which might not be sustainable in terms of energy saving. Experiments have been conducted over the past three years to find a cost-effective, passive on-site wastewater treatment process to improve nutrient removal. The inclusion of recirculation sand filter (RSF) might be a suitable intermediate process to trigger the proper nitrification/denitrification process between the septic tank and the drain field. This option may be adopted for these existing traditional septic tank systems as a retrofit project. Yet the science question as to how effectively the nitrification and denitrification can be fostered in an RSF remains unclear. Three types of medium: fine sand, course sand, and green sorption media (i.e. denoted as options 1, 2 & 3 in this study) were used to assess the performance of the RSF. In particular, phosphorus removal from the wastewater was one of the key concerns, and the capability of using limestone for phosphorus removal was also investigated and confirmed. It can be concluded that fine sand with limestone mixture had better performance for nutrient removal if clogging issue can be overcome by using a grinder pump when dosing. On average, the septic tank and RSF system with fine sand removal efficiencies were: 60.54% ammonium, 49.48% total Kjehldahl nitrogen (TKN), 42.57% total nitrogen (TN), 92.06% soluble reactive phosphorus (SRP) and 87.16% total phosphorus (TP). The E. Coli removal efficiency by RSF was 99.9% in all cases. However, the addition of green sorption media is not favored due to insufficient hydraulic residence time (HRT). If the size of the RSF can be increased, the use of green sorption media in combination with limestone might be beneficial.

The conventional decentralized sewage collection, treatment, and disposal systems are no longer able to fully respond to the needs of handling removal of nutrients.. Without proper sorption and nitrification/denitrification, a large fraction of nutrient loads such as nitrogen and phosphorus flowing into aquatic system may adversely affect the water quality and public health. Constructed wetland, a cost-effective small-scale wastewater treatment system with low energy and maintenance requirements and operational costs, may well fit the current needs. A subsurface constructed wetland system as designed as a performance-based passive on-site sewage treatment and disposal system (OSTDS) was proved effective after receiving septic wastewater flow. With the aid of a suite of locally adapted and selected plant species, such an OSTDS was configured to handle 189 cubic meters per day (50 GPD) influent using green sorption media at the test center located on the main campus of University of Central Florida (UCF). During the test run, results indicate that wetland 1, which was planted with Canna, achieved the best removal efficiency of 97.1 %, 98.3 %, 99.98 % and near 100.0 % for TN, TP, fecal coli and E.Coli, respectively.

A porous concrete parking lot site in Randolph, Vermont is studied in order to gather information on the effect of porous pavement on the site's local hydrology. The study includes analysis of field measurements and the use of a mathematical model to interpret field data.

This paper provides statistical analysis of flow exchange and salt loading between the Rio Grande and underlying aquifers for the Rio Grande Project Area, extending from Caballo Reservoir in New Mexico, continuing through the urbanized areas of Las Cruces, New Mexico and El Paso, Texas to Fort Quitman, Texas. The authors analyzed the river flow, TDS and salt loading at selected three segments of the river reach and associated underlying aquifers. The total salt loading within each segment was computed to determine exchange of salt loading between the river and underlying aquifers. The salt concentrations continue to increase downstream, up to 3,200 mg/L on average at Fort Quitman during irrigation season, approximately five times higher than the water TDS released from the Caballo Reservoir. This is due to the river collecting irrigation return flows, municipal wastewater discharge and natural discharge of saline groundwater. Salt exchange patterns between the river and underlying aquifers were also identified.

With growing populations and increased demand for water, it is necessary to ensure that increased pumping of aquifers does not reduce flows in rivers to levels that would limit the availability of water for drinking water supply, irrigation, and riparian habitat. Analytical solutions and numerical simulations have been used to quantify stream depletion, which is the change in stream flow due to pumping. Typically, in these approaches, the location of the pumping well is assumed to be known; thus they can be inefficient as a tool for siting new well locations. In this work, we use an adjoint-based modeling approach to quantify stream depletion due to aquifer pumping. In a single simulation of an adjoint model, stream depletion is calculated for a well at any location in the aquifer; thus, it is computationally efficient when the number of well locations or possible well locations is large.

Communities and government world-wide have growing concern over the protection of groundwater resources. We have been studying smart markets as a tool to efficiently allocate groundwater, to protect against groundwater depletion, and to prevent damage to environmentally sensitive areas. In this paper, a smart market is proposed for the combination of ground water and surface water, which includes bids for reservoir releases by a hydropower generator. The smart market here is a periodic auction which uses an optimization model to allocate water. The optimization model includes physical constraints based on the aquifer, surface water availability as calculated in a simulation model, and user bids. The simulation model calculates characteristics of an aquifer such as water availability and the interaction under various pumping regimes with surface water, as water is released for hydropower generation. In addition to the physical constraints provided from the simulation model, the optimization model is constrained by each user's demand for water. A piece-wise linear demand function relates each user's willingness to pay for incremental volumes of water. Under the market, users can use their water right, or sell some or all of it to the central pool, or buy additional water. Prices are determined by the exchange of water rights in a bidding system, as in an auction. The bidding system is based on each user's demand curve, which relates additional volumes of water to prices that they are willing to pay for that additional volume of water.

Extracting ground water from pumping wells located adjacent to streams can reduce streamflow, a result that is known as alluvial well depletion. Primary factors influencing stream-aquifer interaction during alluvial well depletion are the hydrologic properties of the aquifer, the degree of penetration of the stream into the aquifer, and a potential streambed layer with a hydraulic conductivity different than the aquifer conductivity. Research over the past decade has developed analytical solutions for streams that account for more site-specific features but become mathematically complex. Evaluation of these analytical solutions using field data from multiple regions is needed to assess existing and recently proposed solutions' applicability and predictive capability. At a well site located adjacent to the North Canadian River in central Oklahoma, a stream-aquifer analysis test was performed. Observation wells were installed between the stream and the pumping well and were instrumented with automated water level sensors to measure water levels every 5 minutes. During the stream-aquifer analysis test, a discharge well located approximately 85 m from the North Canadian River was pumped at a constant rate (2180 m³/d) for 90 hrs. Predicted drawdown from several analytical solutions were fit to the measured drawdown to inversely estimate the aquifer transmissivity, T = 790 to 950 m²/d, specific yield, S_y = 0.19 to 0.28, and streambed conductance, λ > 1500 m/d, and then to estimate stream depletion caused by the pumping well. The stream-aquifer analysis test suggested that the stream was behaving similar to a fully penetrating stream with streambed conductivity equivalent to the alluvial aquifer conductivity. For this system, simple analytical solutions were adequate to inversely estimate the aquifer and streambed hydrologic parameters, especially since early-time delayed yield effects were ignored. After only one day of pumping, estimated stream depletion ranged between 30 and 35% of the pumping rate. After five days of pumping, the estimated stream depletion was 60 to 70% of the pumping rate. These results highlight the intense degree of stream-aquifer interaction in this system, which should be accounted for in allocating future water rights.

A better understanding of stream-aquifer interactions is needed both for water policy and for quantifying its impact on stream chemistry and water quality. Assuming homogeneity in alluvial aquifers is convenient but limits our understanding of stream-aquifer interactions. Previous research in the Ozark ecoregion, which is characterized by cherty soils and gravel bed streams, identified subsoils with hydraulic conductivities of 140 to 230 m d^–1 and showed non-uniform groundwater flow. In a preferential flow path (PFP), even a sorbing contaminant, such as phosphorus, was found to be transported and not significantly attenuated through the subsurface. The objective of this research was to document the impact of flow heterogeneity (i.e., PFPs) on groundwater flow patterns, which will strengthen current understanding of contaminant interaction between streams and alluvial aquifers. Long term monitoring was performed adjacent to the Barren Fork Creek and Honey Creek in northeastern Oklahoma. Based on results from subsurface electrical resistivity mapping, observation wells were installed both in PFPs and in non-PFP subsoils. Water levels in the wells were recorded real-time using pressure transducers. Plots of the water table elevation, streamlines, and water level divergence were generated using six weeks of data including multiple high flow events. Divergence was used to quantify heterogeneity in hydraulic conductivity. The activity of PFPs depended on the elevation of the water table and the interaction between the stream and the groundwater. It appeared that PFPs acted as divergence zones, allowing stream water to quickly enter the groundwater system, or as flow convergence zones, draining a large groundwater area.

Wastewater impoundments at livestock facilties represent a potential source of veterinary pharmaceuticals and steroid hormone contamination to shallow groundwater. This study investigates the occurrence of seventeen veterinary pharmaceuticals and thirteen steroid hormones and hormone metabolites in lagoons and adjacent groundwater at operating swine and beef cattle facilties. Pharmaceutical compounds detected in samples obtained from cattle facilities include sulfamerazine; sulfamethazine; erythromycin; monensin; tiamulin; and sulfathiazole. Lincomycin; ractopamine; sulfamethazine; sulfathiazole; erythromycin; tiamulin and sulfadimethoxine were detected in samples from swine facilities. Steroid hormones were detected less frequently than veterinary pharmaceuticals in this study. Estrone, testosterone, 4-androstenedione, and androsterone were detected in impoundments at concentrations ranging from 0.04 to 3.6 ppb. Estrone and testosterone were infrequently detected in groundwater samples at concentrations up to 0.50 ppb. These data indicate that groundwater underlying livestock facilities is susceptible to contamination by veterinary pharmaceuticals and steroid hormones originating in wastewater lagoons.

The persistence and toxicity effects of endocrine-disrupting chemicals, including environmental estrogens, have not been well-characterized in wastewater treatment plant mixing zones. This study examines the levels of environmental estrogens present in the mixing zone of a shallow effluent-receiving stream in Charlottesville, VA and determines the key compounds that drive the estrogenicity in this portion of the stream. The endogenous estrogen, 17β-estradiol, and the plasticizer bisphenol-A were measured at concentration ranges of 10–176 ng/L, and 0–12 ng/L, respectively. The WWTP was found to be the main source of these compounds. Other known environmental estrogens were not detected at significant levels; hence 17β-estradiol is believed to be the driver of estrogenicity. Analysis of the bed sediments did not yet detectable levels of the target compounds likely due to the very low organic fraction of the sediments.

Understanding bacterial transport through subsurface porous media is critical both for characterizing contamination of drinking-water bodies and designing successful bioremediation strategies for contaminated sites. There has been much effort devoted to studying bacterial and colloidal transport in porous media, where the black box approach has been used to predict transport phenomena based on input and output parameters. Recently, flow cells and micro-models have been used to visualize colloidal transport in porous media to simulate bacterial transport. However, additional factors such as bacterial random motility, chemotaxis (directed migration toward a contaminant source), attachment-detachment, growth and decay influence bacterial transport phenomena and need to be quantified and considered carefully in order to predict bacterial transport accurately. The aim of this study is to quantify the role of chemotaxis in bacterial transport through a two-dimensional micromodel with a contaminant source. In this study a novel bi-layer polydimethylsiloxane (PDMS) micro-fluidic device was fabricated using photolithography and soft lithography techniques to simulate contamination of groundwater due to leakage from an underground storage tank. This device consists of a porous channel through which a bacterial suspension is flown and another channel for injecting contaminant into the porous channel. The device facilitates visualization of both bacteria and a chemical tracer flowing through porous media and is therefore useful in determining their mutual spatial distribution in porous media. The study focuses on studying enhancement of contaminant mixing in porous media due to the presence of bacterial motility. FITC (fluorescein isothiocyanate) was used as a tracer and changes in the fluorescence intensity profiles at different locations downstream from the injection point was used to evaluate the enhancement in the contaminant mixing. Results indicate a two-fold increase in the effective dispersion coefficient of FITC in the presence of bacteria. This device may also be used for determination of Escherichia. coli HCB33 (wild type) chemotaxis toward L-aspartic acid by imaging bacterial and contaminant (tracer) flow at different cross-sections downward of the injection point. Data obtained from this study will fit into the advection-dispersion equation with an additional term form chemotaxis, to calculate chemotactic sensitivity parameters in the microfludic device.

The purpose of this study is to demonstrate the use of a linear control theory model. The model is used to reconstruct the contamination history in an aquifer characterized by limited property information as well as limited contaminant concentrations data at several observation points (Guan, et al., 2009). The data that may be available to reconstruct the historical groundwater contamination at the contaminated sites, which are utilized in this approach, might contain various uncertainties such as measurement errors or data gaps. In addition to these data errors, the model used to reconstruct the historical contamination may also introduce numerical errors to the overall analysis. Evaluation of the effects of these uncertainties and numerical errors is a challenging topic. In this study, numerical and field data errors are embedded into the linear control theory model resulting in a linear stochastic control system. The Kalman filtering method coupled with Monte Carlo simulation is then used to analyze the effect of these errors on concentration distributions at observation sites that are reconstructed. Using this procedure, the temporal confidence "corridor" of concentration distributions at observation sites can be constructed for a selected confidence interval. For demonstration purposes, the proposed methodology is applied to recover contamination history at the Tarawa Terrace area of U.S. Marine Corps Base Camp Lejeune, North Carolina. Numerical results obtained show that the methodology provides an effective and robust tool to reconstruct groundwater contamination history with uncertainties. The confidence corridors obtained for a given confidence interval can provide the necessary information on the uncertainty of the predicted results.

In this paper, a new probabilistic symmetry analysis approach is proposed to the analysis of nonlinear hydrologic processes and is applied to the analysis of nonlinear two-dimensional groundwater flow subject to random hydraulic conductivity field. Symmetry methods can be used to transform almost any kind of linear or nonlinear partial differential equation (PDE) that represents a hydrologic process in any dimension to an equivalent ordinary differential equation (ODE). Following this methodology, the two-dimensional Boussinessq equation for unconfined groundwater flow in a heterogeneous aquifer is transformed to a system of ODEs through Lie Group symmetry analysis in order to eliminate the spatial derivatives occurring in the governing equation. Meanwhile, it was recently shown that the conservation equations of hydrologic processes under uncertainty, expressed as linear or nonlinear stochastic ODEs or PDEs, have a one-to-one correspondence to a mixed Eulerian-Lagrangian nonlocal form of the Fokker-Planck Equation (FPE) when the underlying process has finite correlation lengths (Kavvas 2003). Under such correspondence it is possible to obtain a solution for the ensemble behavior of a particular hydrologic process in terms of the solution of its corresponding FPE for the PDF of its state variables under appropriate initial and boundary conditions. Then, using this ensemble averaging technique the derived nonlinear stochastic ODEs are then transformed to a mixed Lagrangian-Eulerian FPE. Next, the FPE is solved numerically under the appropriate initial and boundary conditions in order to obtain the mean hydraulic head and associated uncertainty (expressed in terms of the hydraulic head variance and hydraulic head probability density function). Finally, the proposed method is tested against the Monte Carlo simulations. Comparison of the results shows that the proposed method is highly promising for estimating the time-space behavior of the mean and variance of the hydraulic head in heterogeneous aquifers.

Salt water intrusion is a process where saline water would naturally intrude into fresh groundwater regions of a coastal aquifer. The process is caused by the higher density of the ocean waters and is often exacerbated by the extraction of fresh ground water in overpumped catchments (Kacimov et al, 2009). A major factor that drives the intrusion process is the density difference. The salt water intrusion process has a significant role in water management in coastal region. It is because a small fraction of the intruded salt can increase the salinity level of an impacted aquifer. Therefore, the location of the interface between the freshwater and saltwater, commonly known as the saltwater wedge, should be carefully managed in coastal areas to avoid an unexpected contamination of drinking water reserves. The salt water wedge could be influenced by various climate patterns or regional rainfall characteristics. Werner and Simmons (2009) explored the changes in the location of the saltwater interface caused by sea level variations in an unconfined coastal aquifer. They illustrated how various factors such as recharge rate, hydraulic conductivity, aquifer thickness, and the rate of ground water discharge would influence the movement of a steady-state wedge. They predicted the movement of the wedge toes due to sea-level changes using an idealized steady-state analytical solution. Most realistic field-scale saltwater management problems involve the use of numerical models to make predictions. These models require benchmarks to test their validity. Henry Problem (1960) developed an analytical benchmark problem that has been widely used for validating saltwater intrusion models. Goswami and Clement (2007) conducted a laboratory-scale benchmark experiment for mapping the transport patterns of a saltwater wedge. Abarca and Clement (2009) developed the visualizing method to map a mixing zone between freshwater and salt water interface. In this study, the original Henry benchmark problem was modified to account for areal recharge boundary conditions. We used SEAWAT model to simulate a problem involving regional flux boundary condition and a problem involving recharge flux boundary condition. SEAWAT simulator combines MODFLOW and MT3DMS as a single code to solve the coupled flow and solute-transport equations (Guo and Langevin, 2002). The objectives of our study is to verify a numerical solution with laboratory experiments for a Henry-type benchmark problem involving various flux type boundary conditions and to understand the movement of toe positions due to sea level change through the verified numerical approach. For the two dimensional cross sectional experiment, a soil tank was designed with 50 cm x 28 cm x 2.2 cm dimension. The tank was relatively thin for describing two dimensional domain. The central flow chamber was filled with porous media of 1.1-mm diameter silica beads. A digital photography was used to record the wedge position. The digital data allowed us to zoom and observe small-scale variations allowing quantitative analysis of the wedge and observation of the small-scale transport processes at work. These observations will be used to calibrate a numerical model. The simulation result completed by SEAWAT was compared to the experimental data for the location of saltwater wedge. Our results indicated that the numerical model agrees well with the experimental results for three steady states of (a) regional boundary condition and (b) Areal-recharge boundary condition. The three sets of steady state experimental condition were designated as SS1, SS2 and SS3. Under relatively high incoming flux, the shape of the wedge was not significantly different. SS1 and SS3 results showed almost same length of the toe position and the same discharge boundary (point of contact of salt water wedge with the left boundary). A relatively low incoming flux made different type of wedge. The areal recharge boundary broadened the discharge zone due to greater water flow rate. We performed sensitivity test for the head difference and freshwater flux for the each experiment. Even though the head difference is very sensitive to the model feasibility, we obtained generally good agreement between numerical model simulation and experimental results. Finally we studied the effects of sea-level rise in flux-controlled groundwater problems. In this case, the experimental tests were not employed. We have made an attempt to generate similar looking salt wedges using two distinctly different boundary conditions. (Q/b of original Henry problem is 0.66 cm²/s upon a 200 cm x 100 cm domain). As a next step, the salt water head was increased to model the sea-level rise. These theoretical simulation results are applicable on a coastal region where recharge flux is dominant, such as an island.

Ground water is an important water supply source for many coastal communities. Significant ground water extraction can lead to landward migration of the saltwater-freshwater interface, which can contaminate the water supply. It is therefore important to consider the potential for saltwater intrusion when developing a ground water management plan in coastal regions. An important tool in analyzing such problems is the numerical model which can predict water levels, ground water flow, and the location of the salt-water interface given a particular pumping regime. Such models require knowledge of hydraulic parameters for each aquifer. Imprecise specification of these parameters can lead to inaccurate results and it is therefore important to evaluate the effect of uncertainty in model parameters. Because the hydraulic conductivity of an aquifer is critically important for predicting the location of the saltwater- freshwater interface, it is a major source of uncertainty in ground water analysis. Here we investigate two types of uncertainty in the context of ground water management problems: (1) modeler's uncertainty reflects inaccurate estimation of mean hydraulic conductivity, and (2) spatial variability reflects our inability to adequately characterize the spatially heterogeneous distribution of hydraulic conductivity at an appropriate scale for precise modeling. Both types of uncertainty are investigated by developing a ground water management problem based on a coastal aquifer on Cape Cod, Massachusetts. The management problem seeks to minimize the threat of saltwater intrusion while meeting the water supply demands of the community. The two types of uncertainty are shown to have different and substantial effects on optimal management designs. These results illustrate the importance of considering uncertainty in determining ground water management solutions in a coastal aquifer environment.

This study outlines systematic order-of-magnitude differences between, on the one hand, consistent seepage measurements with inland hydrology-based estimates and, on the other hand, coastal-marine tracer-based estimates of submarine groundwater discharge (SGD) in different parts of the world. We investigate here, by different field case simulations, whether groundwater flow transience, caused by temporal variability on different time scales, may add a sufficient contribution to SGD from seawater intrusion (SWI) and re-circulation back into the sea to explain the major differences between different SGD estimation methods. The investigated temporal variability factors include tidal oscillation, and seasonal and long-term hydrological and water-use variability and change. Neither of these factors effects on SWI and its contribution to SGD could explain the major SGD estimation differences. A previously suggested explanation, regarding the neglect of tracer discharges into the sea through unmonitored near-coastal streams and river stretches in coastal-marine tracer-based SGD estimations, still goes much farther in identifying a main reason for the large SGD estimation differences by different methods.

This study was carried out to quantify the presence of saltwater along the Lamone River in the province of Ravenna, Italy, to estimate the seasonal dynamics of the salt wedge and to establish its contribution to the salinization of the adjacent aquifer. The Lamone River is a small river with a low average discharge of 8 m³/sec that flows from the Apennines to the Adriatic Sea through the southern Po Plain; the salt water encroachment has been monitored by means of monthly vertical electrical conductivity profiles in 32 stations in the centre of the river, along its terminal 8 kilometres. Measurements showed that there is a salinity stratification that is typical of low discharge river estuaries in micro tidal conditions. The electrical conductivity at the bottom of the river equals that of seawater (45 mS/cm) almost all year long. Only the spring flood events that in some cases reach 80 – 100 m³/sec, are able to push the salt water out. Fluvial fresh water in most months is present as a one meter thick layer floating on the dense salt water. At 6.5 km from the sea, the presence of a rocky sill represents an efficient threshold that blocks the salt wedge. The bathymetry of the river was surveyed both indirectly with CTD probe depth measurements and with a coupled DGPS/Ecosounder campaign. Results showed that the Lamone has an unusual inverse riverbed slope, with depth increasing inward from the mouth ranging from –1.5 m.s.l. to – 4 m.s.l. at 6.2 km from the mouth, and a very irregular bottom surface characterized by the presence of holes up to several meters deep. Both the inverse riverbed slope and the deep holes in the river bottom explain why saltwater easily enters the river and remains trapped for most of the year. The salt pools on the river bottom may represent one of the major sources of salinization of the adjacent aquifer. Continuous monitoring of piezometric head and conductivity in observation wells and in the river shows that the two systems are connected and the river transmits the tidal fluctuations to the shallow unconfined aquifer.

Seawater intrusion is a common problem in almost all coastal aquifers. However, the degree of intrusion may differ from one aquifer to another depending on many factors including, among others, geometric and geological conditions of the coastal aquifer, hydrological parameters, climatic conditions, pumping rates and recharge events. Proper assessment and mapping of the groundwater quality and transition zone in coastal aquifers are needed for any groundwater management in coastal aquifers. Geophysical methods represent a feasible tool for the monitoring and assessment of seawater water intrusion problems in coastal aquifers. This paper presents earth resistivity surveys that have been conducted in the coastal aquifer of Wadi Ham in United Arab Emirates. Existing monitoring wells were used to measure the horizontal and vertical variations in water salinity and thus improve the interpretation of earth resistivity imaging data. Results of 2D earth resistivity imaging surveys and chemical analyses of collected water samples were used to obtain an empirical relationship between the inferred earth resistivity and the amount of total dissolved solids. A three-dimensional mapping of the seawater intrusion transition zone was developed through the integration of two-dimensional vertical resistivity profiles. The paper demonstrates the feasibility and accuracy of geophysical methods in three-dimensional mapping of seawater intrusion problems.

The coastland surrounding the southern Venice Lagoon, Italy, is a precarious environment subject to both natural changes and anthropogenic pressure. One major environmental problem is the saltwater contamination in shallow aquifers. Since the early 2000s, a significant effort has been devoted to understand the process dynamics by integrating different geophysical techniques, i.e. TL-ERT (Time Lapse - Earth Resistivity Tomography), MRT (Marine RT), AEM (Airborne ElectroMagnetic), and shallow water VHRS (Very High Resolution Seismic) surveys. The monitoring results have been used to drive the development of a reliable numerical model for the simulation of the saltwater intrusion along the margin of the southern Venice Lagoon. The model solves the coupled density dependent flow and transport equations by a highly accurate numerical approach based on the mixed hybrid finite element (MHFE) method and a combination of MHFE with high resolution finite volumes (HRFV) for the discretization of the flow and transport equations, respectively. Modeling application provides a clear picture of the relative importance of the factors that contribute to the soil contamination in the study area.

The unsaturated soil behavior is of primary importance in many of the field situations like flow of water through vadoze zone, deciding irrigation requirement for various crops, evapo-transpiration, deciding fate of contaminants in the geoenvironment etc. The reliability of these studies largely depends on the precise characterization of unsaturated soil, which includes the measurement of soil suction. One of the most important applications of measured values of soil suction is to obtain its variation with water content (gravimetric or volumetric) or saturation of the soil, which is termed as soil-water characteristic curve (SWCC). Tensiometer is one of the most popular methods of suction measurement and establishing SWCC. It is noted that there are different contrasting studies pertained to the effect of dry unit weight on measured soil suction. Therefore, the present study aims to investigate the role of dry unit weight on soil suction using tensiometric measurements for a locally available soil. SWCC has been obtained and the influence of dry unit weight on the SWCC is discussed in this paper.

Ethanol is increasingly used as an automotive fuel in an effort to diminish the use of fossil fuels and to reduce the emission of contaminants into the atmosphere. This study is concerned with the potential negative impact of the (accidental) release of ethanol to the subsurface. Spillage and leakage of ethanol may occur accidentally during production of blended fuels,, transport, storage, handling, or use. It will often occur in the vadose zone, i.e., from the soil surface to the water table where the soil or rock contains both water and air. Ethanol is highly miscible with water. It will reduce the air-water surface tension and alter the viscosity of aqueous solutions. Therefore, ethanol may affect the transmission and retention of water and dissolved contaminants in the vadose zone. There is an urgent need to quantify this effect. In the present study changes in the hydraulic properties of porous media due to ethanol are examined. In particular, we incorporated the surface tension of aqueous solutions as a function of the ethanol concentration in the water retention function with the "air entry" value. Furthermore the changes in hydraulic conductivity with ethanol content have been quantified through the definition of a function that relates the solution viscosity to ethanol content. The HYDRUS-1D model developed for water flow and solute transport in unsaturated soils was modified by introducing a subroutine that performed the scaling of the water retention curve and the hydraulic conductivity function according to the ethanol concentration. The code was used to model three different scenarios. In the first scenario, ponding and redistribution of pure ethanol in an ethanol-free soil column is compared with ponding and redistribution of pure water. The results show that the amount of pure water that enters the soil is larger than the ethanol and that pure water will move faster than pure ethanol. In the second scenario we compare spillage with no spillage of ethanol at the soil surface followed, in both cases, by a dry atmospheric condition, precipitation, and again dry atmospheric conditions. The ethanol spillage will lead to a higher water content in the upper part of the soil. In the third scenario, we compare water flow in columns with a 10% initial ethanol content (contaminated soil) and without initial ethanol (pristine soil). Both columns are subjected to precipitation (infiltration) followed by dry atmospheric conditions (redistribution). The higher conductivity of the pristine soil causes a rapid infiltration of water during precipitation and advancement of the liquid front during redistribution compared to the contaminated soil.

In this paper we present a method that enables simulation of permeability, formation factor and pressure-saturation relations in reconstructed porous media. The simulation is performed based on the three-dimensional geometric description of the complex microstructure of physically-realistic unconsolidated porous media. Packings of soil particles of arbitrary shapes numerically generated to mimic natural subsurface systems using an optimization based algorithm. The algorithm arranges soil particles (i.e., locations and orientations) so that the simulated system matches predefined geometrical and topological distributions of natural subsurface porous media system. X-ray computed tomography is used to capture the three-dimensional geometry and topology of samples of natural sediments to create a shape library which is used as input in the search for locations of soil particles. The shape library provides information about lengths, shape indices (i.e., sphericity and angularity) of all particles in a given packing. The medial axis of each particle, a combination of a skelton and burn numbers, is obtained and incorporated in the optimization algorithm to search for optimum locations of particles. The algorithm uses multiple points (points on boundaries of particles) and multiple radii (principal lengths of particles) to locate particles in a given domain to generate realistic packings in terms of porosity, shape indices and points of contacts between soil particles.

The ability to deliver remediation amendments into contaminated sediments without negatively impacting benthic organisms and their environments has proven to be challenging. The use of waterjets to perform this delivery of remediation amendments at depth is a viable alternative. Waterjets are a viable alternative for placement of remediation amendments at depth. An amendment injection system and waterjet nozzle has been developed to test the merit of this concept. The injection system's performance was assessed by characterizing the distribution of delivered amendments throughout a surrogate sediment test bed. A novel spectrometry method was developed for powdered activated carbon characterization, while granular iron was characterized using two different methods, visual comparison and Inductive Coupled Plasma analysis. Distribution of the placed amendments illustrated similar patterns for a range of injection times and amendment types. However, the depth of injection was dependent upon the type of amendment being injected. The findings of this study has lead to a better understanding on what occurs during an amendment injection, which will aide in and allow for more controlled placement of remediation amendments in the future.

The New York State Thruway Authority (NYSTA) has recently completed a bridge scour reevaluation and plan of action (POA) for the I-90 bridge over Cattaraugus Creek, located in Western New York State. Following the collapse of the I-90 bridge over Schoharie Creek in 1987, the Authority evaluated its entire 560 mile system, and the I-90 bridge over Cattaraugus Creek was designated, as a scour critical bridge because the foundations of the bridge were found by calculation to be of insufficient depth to prevent the bridge from collapsing when subjected to theoretical scour from the 500-year flood event. Highlights of the scour reevaluation and POA include: a 30% reduction in theoretical local pier scour predictions using current HEC-18 pier scour equations and new survey; pier cofferdam survivability analyses using updated record information and analyses methods; troubleshooting of previously installed scour monitoring devices and field assessment of previously constructed scour countermeasures; development of improved flood and post-flood monitoring and inspection procedures; and recommendations for additional scour countermeasures to protect the bridge for its remaining useful life. During the scour reevaluation process, on August 10, 2009, the bridge experienced the second largest flood since construction of the bridge, a 50-year flood event.

The Generalized Environmental Modeling System for Surfacewaters (GEMSS) is being used to create a three-dimensional hydrodynamic and transport model of the North Basin of the Wachusett Reservoir, located in central Massachusetts. GEMSS computes time-varying velocities, water surface elevations, and water quality constituent concentrations in rivers, lakes, reservoirs, estuaries, and coastal water bodies. A three-dimensional grid has been created for the GEMSS model. Boundary conditions will be added to the model by incorporating output from a prior two-dimensional model for the entire reservoir.

In an effort to restore fisheries within Lake Champlain from the harmful behavior of the parasitic sea lamprey both federal (U.S. Fish and Wildlife) and state (New York State Department of Environmental Conservation and Vermont Fish & Wildlife) agencies have been working together to develop a sea lamprey control program. Sea lampreys are eel-like fish that feed on other fish, most often salmon or trout, however their prey include a variety of other fish species. Their presence has had a significant effect on the survival of the fish community within the lake as well as the fishing industry that has been built around the lake. As young sea lamprey spend the first four years of their lives within the bottom surface of the rivers and reaches that discharge into Lake Champlain, one component of the control program is the use of a chemical lampricide in these areas to control the young lamprey population. Lampricide applications are effective at targeting lamprey while having negligible effects on populations of other species. Applied Science Associates, Inc. (ASA) was contracted by the Vermont Fish and Wildlife Department to perform a hindcast study of the application of lampricide 3-trifluouromethyl-4-nitrophenol (TFM), which took place in November 2008 at the Swanton Dam in the Missisquoi River. The Missisquoi River discharges into Missisquoi Bay which is a small embayment located in the northeastern corner of Lake Champlain. Prior to the TFM application ASA had completed a modeling study to estimate the extent and duration of TFM in the study area under a variety of application and environmental conditions; however the studied conditions varied significantly from those observed during the actual application. All modeling efforts were performed using BFHYDRO and BFMASS, part of ASA's WQMAP modeling system (Mendelsohn et al., 1996), to simulate the circulation and mass transport respectively. WQMAP is a boundary-fitted model which can be used in three dimensions to predict flow, velocities and mass transport. The model system calculates the circulation and mass transport in the far-field region, where the initial plume momentum has dissipated and the plume is affected only by the ambient currents. This paper includes an overview of the WQMAP modeling system, relevant environmental conditions used for model forcing, model predictions and a comparison of model predicted concentrations to those observed during the field program executed by Vermont Fish & Wildlife; due to publication length requirements the reader is often referred back to the original comprehensive hindcast study report (Crowley et al., 2009). In the hindcast study observational data was used to validate the WQMAP numerical model application for use in simulating the fate and transport of the conservative constituent TFM. While numerical modeling limitations resulted in under predictions of peak concentrations at increasing distance from the application point, the model performed well at recreating the extent of the plume both spatially and temporally.

This paper presents the development and application of a three-dimensional numerical model for simulating the flow circulations in Lake Pontchartrain, LA. The water movements within the lake are primarily wind and tide induced. Tidal currents influence the lake circulations through a few narrow passages with mild amplitude of the tidal cycles. The wind and tide-induced hydrodynamics dominate transport processes in the lake. In this study, the developed model was first verified against analytical solutions of wind-driven and tide-driven flows; then it was applied to simulate the flow fields in Lake Pontchartrain. This model was also applied to simulate Hurricane Rita induced flow fields. The simulated water surface elevation and flow currents were generally in good agreement with field measurements provided by the United States Geological Survey (USGS). This model provides a useful tool to analyze the flow currents induced by wind and tide in large natural lakes.

The North Side Water Reclamation Plant (NSWRP) is one of the seven water reclamation plants owned and operated by the Metropolitan Water Reclamation District of Greater Chicago (MWRGC) and serves a population of around 1.3 million people in a service area of 142.4 square miles. Through its history the plant has experienced non-uniform distribution of grit between the tanks 1–10 and 11 & 12. To counter the problem of grit overloading in the 6^th (southernmost) grit tank, the inlet to the tank has to be throttled which on the other hand gives rise to loss of capacity of the grit chamber. Computational Fluid Dynamics (CFD) simulations of the flow and the flow coupled with sediment transport; going into the aerated grit tank were done using the CFD modeling code, FLOW-3D®. It was observed that for higher pumping rates (Q ≥ 225 mgd) the flow in the distribution system became unsymmetrical with relatively lower velocities and discharges on the southern side of the distribution system, especially in distribution channels 11 and 12. Similarly the sediment deposition distribution showed a clear shift towards channels 11 and 12 with increase in discharge, this goes to show the tendency of the sediment to move along the southernmost channels. A possible mechanism for explaining the non-uniform grit deposition in the aerated grit chambers has been discussed and it has been backed by the generation of a secondary current at the bend and the Bulle Effect.

Flood flows in alluvial channels (rivers) convey suspended sediments from upstream to downstream, and also entrain bed materials along with flood currents. It is obvious that morphological changes in channels due to sediment deposition/erosion will affect water stages, and results in different hydrographs, in comparison with those in a fixed channel bed. During flood seasons, due to speeding flood currents, even drastic bed changes will occur. It is therefore of importance to take into account morphological changes in alluvial channels induced by flood flows for the purpose of flood control operation. This paper presents a systematical numerical investigation on the effect of morphological change in an alluvial channel on optimal flood control. As an example, the numerical optimal flood control is demonstrated by operating a floodgate to withdraw flood waters from a channel. The optimal withdrawal hydrographs for the floodgate operations are obtained by an integrated numerical optimization modeling system which consists of a hydrodynamic model, a sediment transport model, and a bound constrained optimization model. The hydrodynamic module is to solve the one-dimensional nonlinear de Saint-Venant equations. The sediment transport module solves the non-equilibrium transport equations for non-uniform sediments. And the optimization module is to find the optimal solution iteratively by solving the adjoint equations of the Saint-Venant equations obtained by variational approach. In order to study the effectiveness and applicability of the optimal control theory, alluvial channels with single floodgate is considered for different flow conditions and sediment properties. The changes in morphology due to control of flows are studied thoroughly. It is found that the influence of morphological changes on flood control becomes critical under certain flow conditions and the integrated model is applicable to perform optimal flood control under consideration of sediment transport in alluvial channels/rivers.

In order to predict hydraulic jump characteristics for channel design, jump height may be determined by calculating the subcritical sequent depth from momentum theory. In closed conduits, however, a hydraulic jump may fill the conduit entirely before the expected sequent depth is reached, resulting in the aptly-named "incomplete" jump. This requires the sequent depth equation to account for both open-channel and closed-conduit flow. When using momentum theory to calculate sequent depths in conduits, it is commonly assumed that the conduits are prismatic, fairly horizontal, and relatively frictionless within the jump length; that the pressure is hydrostatic and the velocity is uniform at each end of the jump; and that the effects of viscosity and air entrainment are negligible. However, research recommends that air entrainment be included in closed-conduit sequent depth calculations. This paper therefore reviews momentum theory as applicable to hydraulic jumps in closed conduits, provides a general sequent depth solution that accounts for air entrainment and which is applicable to complete and incomplete jumps within all conduit shapes, and then compares these solutions to those that do not account for air entrainment. In practice, these solutions may be used to more accurately predict the size and location of potential hydraulic jumps within conduits and culvert barrels in order to facilitate cost-effective designs for energy dissipation.

Sediment transport through culverts is poorly understood. Current design methods for culverts are generally based on the characteristics of open channel flow. A careful analysis of previous studies reveals significant differences between open channel flow and flow through a culvert. The purpose of this paper is to identify and categorize the main differences between open channel flow conditions and flow through a culvert embedded in native substrate. The differences in flow characteristics are most easily identified when separated into four categories: geometry, sediment/debris, bed integrity and aquatic life. The geometry of a culvert creates conditions unlike the natural channel in high discharge conditions. A culvert could experience pressurized flow or orifice flow and often needs an entrance loss coefficient to accurately predict flow. There are also differences in shear stress when a streams aspect ratio is decreased by a culvert. All culverts will eventually constrict flow to a smaller area than found in non-incised open channels. Under these conditions, an embedded culvert will often be submerged at the inlet and unsubmerged at the outlet, exacerbating the already constricted flow conditions and resulting in more scour at the entrance and exit. This also can create deposition or floating debris issues at a culvert entrance. The bed of an open channel is much different than in an embedded culvert due to the integrity of the bed structure. A bed placed in a culvert cannot mimic the actual structure of a stream bed because of the sediment sizes and configuration. This causes the bed to be more susceptible to interstitial scour and in some cases can cause the entire fish passage design flow to travel through the bottom of the bed seemingly disappearing while in the culvert. Because culverts are placed in streams, they can potentially cause biological longitudinal continuity issues. These issues are very complex and need to be studied from multiple disciplines. The lack of light in long culverts could prevent certain vegetation from growing and the shade of a culvert has been shown to be a deterrent to some fish species. Knowing the differences between open channel flow and flow through a culvert is crucial as a starting point in design and as a background for further research. By compiling and categorizing a current list of differences, we can begin to understand the complexities of creating functioning culverts as well as researching solutions to minimize these differences. This is especially important in the quickly emerging field of culvert design for aquatic organism passage, where creating conditions within the culvert barrel that mimic those in the open channel is critical to the design procedure.

Hydraulic transient events can result in excessive pressures leading to catastrophic pipe and/or equipment failures, and possibly injuries or even fatalities, if water hammer phenomena are not accounted for in the design and operation of the Liquefied Natural Gas (LNG) and/or LNG byproduct conveying pipelines. Additionally, leaking of hazardous liquid due to water hammer damage can contaminate the environment and threaten the health of wild life and human beings. With the steady increase of LNG trading worldwide, a large number of LNG loading and unloading pipelines have been built in the past decades. Using lower piping class and schedule is a common cost-saving choice. However, it puts the pipeline systems in greater danger as various hydraulic transient events occur within the increasingly complicated pipelines during loading or unloading to or from the dedicated LNG carriers (ships). In this study, transient pressures and dynamic loads associated with pump trips, valve closures, column separation, and column rejoining initiated by the potentially troublesome operating conditions are simulated numerically. Recommended pressure and loading mitigation measures include slowing down of valve closure, increasing pump polar moment of inertia, placement of surge relief vessels, avoiding check valve slamming, and establishing safe system operation procedures.

In June, 2008, the Mississippi River in the Midwest USA experienced a high flood. More than 22 breached levees were observed along the Mississippi River, resulting in at least 24 fatalities in 51 counties of 5 states (Illinois, Missouri, Wisconsin, Iowa, and Minnesota). In order to study the flood impact on agriculture in the flood zones, the computational model, CCHE2D, was applied to simulate levee breaching and flood propagation in one reach of the Mississippi River near Canton City, Missouri. Due to the difficulty to obtain field data for such large scale problems, remote sensing was used to estimate the location, width and timing of breaching as well as distribution of Manning's resistance coefficients. The computational model was validated using experimental and field dam break flow data before applied to this case. A series of satellite imagery and several digital image processing techniques were used to identify the processes of flood wave propagation and inundation in the field for this study. Because levee breaching took a short time in comparison to the overall flooding process, levee breaching process was computed using a simplified model to enhance computing efficiency. A hybrid method to combine the explicit and implicit scheme based models was also developed and applied which greatly reduced the simulation time. The computation results have been compared with a series of digital imagery and it shows the simulation agreed well with what happened. The developed modeling system has a strong potential to be used for emergency management.

Excessive precipitation, fast snow melting, and storm surges due to hurricanes often result in levee breaching and inland flooding which devastates social facilities, residential properties, environment quality and threatens human lives. To enhance the resilience of society, it is important and necessary to study levee breaching flows and develop technologies for repairing damaged levees effectively during the flood. In this study, computational simulations were conducted using a finite element based two-dimensional and depth-integrated numerical model, CCHE2D. Data of a scaled levee breaching physical model were used to validate the computational model. The flood and levee breaching occurred during the Hurricane Katrina in New Orleans, LA, were studied in the Hydraulic Lab, and the measured flow distribution in the vicinity of the breached levee was simulated. The numerical model resulted in good agreement with the measured flow velocity and water surface elevation distribution. The computational model such validated was also applied to simulate the breach closure processes conducted in the physical model. This capability could help emergency managers and engineers to close breached levees more effectively. The practice of placing sand bags into the flow and closing the breaching was mimicked by using a graphic user interface.

This paper presents a two-dimensional numerical model for predicting the overtopping breach of unlined cohesive earthen dams and the resulting flood. The water flow is simulated using the two-dimensional shallow water model based on the control volume method. The HLL approximate Riemann solver is used to calculate the intercell fluxes. The breaching process of cohesive earthen dams is calculated based on the linear model for cohesive soil erosion, which assumes that erosion rate is proportional to the excessive shear stress acting on soil surface. The numerical model has been tested using three problems with analytical solutions or measured data. The results show that the flow model is capable of satisfactorily reproducing various open channel flows, which may include discontinuities, transcritical flows, and flows with irregular geometry. The test case of breach development of a cohesive earthen dam further demonstrates that the proposed model can reasonably predict the breach development in the case that breach growth occurs mainly through progressive surface erosion.

As part of the Combined License or Early Site Permit application process for new nuclear power facilities in the US, detailed flood hazard evaluations are required to support the site safety analysis report. Dam failures are one of the flooding events that have to be considered in accordance with the nuclear regulatory requirements. The dams and impoundment facilities postulated to fail could be located on site or upstream of the site. This paper discusses the modeling approaches and methods used in analyzing the flooding resulting from the failure of water impoundment facilities onsite or near the site. In particular, the antecedent conditions, the solution methods and boundary conditions of a 2-dimensional breach model are discussed.

A depth-averaged 2-D model has been developed for simulating sediment transport and morphology changes due to unsteady flows overtopping coastal levees and barrier islands with homogenous non-cohesive materials. It solves the 2-D flow continuity, flow momentum, sediment transport and bed change equations using an explicit finite volume method on a rectangular grid. It considers interactions among transient flow, strong sediment transport and rapid bed change by including bed change and variable flow density in the flow continuity and momentum equations. The model adopts the HLL approximate Riemann solver to handle the mixed-regime flows near the breach and the wetting-drying problem. It uses the non-equilibrium approach for non-cohesive sediment transport. The developed model has been tested using measurement data, predicting well the breach dimensions and flood characteristics.

The development of potential flooding from a dam failure requires several elements; the hydrologic scenario, the possible dam failure modes, breach parameters that are associated with the failure modes, and the routing and mapping of the consequent discharge hydrograph. The unsteady flow routing model, HEC-RAS, is often used for the computation and display of downstream impacts resulting from hypothetical dam failures. Estimation of the breach parameters, such as width and development time, has typically done external to the model. This paper presents recent research into the use of several breach process models to define HEC-RAS breach parameters. The process models evaluated incorporate several mechanisms for simulating breach development; including vertical erosion due to sediment transport, breach widening, side slope collapse, and head cutting. The use of such process models to provide information regarding the time-history of breach development for use in HEC-RAS is described.

This article presents the development and application of a Finite Elements based flow model for the simulation of dam and levee failure. The unstructured, implicit, finite element model relies on computed residuals to automatically adjust the time step size. The result is an efficient and accurate prediction of both the speed and depth of shock waves as the dam-break flow passes over initially dry and wet land.

This paper describes how geographic information system (GIS) tools contributed to solving flooding problems. GIS not only facilitated model development and analysis, but it was also critical in helping local residents and municipal engineers understand the causes of flooding, the relationship between land use alterations and floodplain impacts, and the potential changes in flooding extents as a result of proposed improvements. CDM was contracted by the town of Greenwich, Connecticut, to complete drainage evaluations for six watersheds that drain into Long Island Sound, covering approximately 26,000 acres. Detailed hydrologic and hydraulic models were developed for each watershed to understand current flooding problems and identify improvements that would alleviate flooding. For each watershed study, CDM participated in meetings with the Town Drainage Task Force, Flood and Erosion Control Board, community residents, and town officials, to understand community concerns and identify flooding problem areas. Based on the data collected, field investigations performed and information from residents, hydrologic and hydraulic models were developed utilizing the Hydrologic Engineering Center's Hydrologic Modeling System (HEC-HMS) and the Hydrologic Engineering Center's River Analysis System (HEC-RAS) computer programs, combined with GIS tools. The Geospatial Hydrologic Modeling Extension, HEC-GeoHMS, was used to extract watershed parameters while the Geospatial Hydraulic Modeling Extension, HEC-GeoRAS, utilized the town's GIS mapping to create river cross sections and map simulated flooding extents. ArcHydro was also used to delineate watersheds and determine longest flow paths. Calibration of the existing conditions model was based on an actual flood event in April 2007. Based on statistical rainfall data, this event correlated to a 25-year storm and was used to calibrate the model. Figures generated using HEC-GeoRAS showing simulated flood extents were presented to residents for validation of actual flooding experienced during the April 2007 storm event. CDM evaluated different alternatives and recommended improvements to alleviate flooding. These improvements were compared using capital improvements ranking criteria developed for the project to prioritize 33 stormwater improvements. The GIS tools were instrumental throughout the project. The GIS database aided in model development and analysis. Also, spatially relating and combining the GIS data and modeling results was critical in helping local residents and municipal engineers understand the causes of flooding, the relationship between land use development and floodplain impacts, and the potential changes in flooding extents anticipated as a result of recommended improvements.

A deterministic 3D model for simulating hydrodynamics and salinity, based on the code Si3D, was implemented for San Francisco Bay. Several scenarios were modeled involving different months with varying estuarine conditions between October 2007 and June 2008. Bay bathymetry, coastal and river water levels, and salinity were used as input. This paper presents preliminary results of the modeling project. The paper discusses results obtained with two meshes and addresses the effects of boundary conditions on the numerical results. Predictions of tidal current patterns were developed for a study of water quality and quantitative pathogen monitoring in the sub-embayment of San Pablo Bay.

The water level guidance, both subtidal and total, from real time oceanographic forecast modeling systems was compared to 24 National Ocean Service (NOS) water level stations on the U.S. East Coast and Gulf of Mexico Coast. The National Weather Service (NWS) Real Time Ocean Forecast System (RTOFS), the NWS Extra-Tropical Storm Surge (ETSS) Model, the United States Navy Global-Navy Coupled Ocean Model (G-NCOM), and the University of North Carolina Western North Atlantic Forecast System Advanced Circulation (ADCIRC) Model water level forecasts were compared with the observations during November 2008. Because the ETSS model is subtidal, the ETSS forecast water levels were compared with observed subtidal water levels, which were obtained using a 30 hour low pass Fourier filter. Because the RTOFS, ADCIRC, and G-NCOM include tides, their forecast water levels were compared with the total observed water level. Two new versions of RTOFS were considered and contrasted with the previous RTOFS results documented in Richardson and Schmalz (2007). Using the hourly nowcast water levels, it was possible to perform a harmonic analysis as well as a subtidal comparison using a 30 hour low pass Fourier filter with subtidal observed water levels for both RTOFS and ADCIRC. Since G-NCOM water levels were at 3-hour intervals, subtidal results could not be obtained via Fourier filter and were obtained by subtraction of the NOS predicted astronomic tide from the total nowcast water level (detiding). The evaluation demonstrates that for total water level forecast guidance, the order of skill in terms of root mean square error (RMSE) is first ADCIRC, next G-NCOM, followed by RTOFS. For subtidal water level forecast guidance, again based on RMSE, the order of skill is ETSS, ADCIRC, RTOFS, and G-NCOM. In conclusion, plans for further streamlining of the water evaluation toolset as well as the extension of the evaluation to salinity, temperature, and currents are presented.

The continuous lowering of Lake Michigan-Huron levels has caused increasing concerns. St. Clair River, which drains Lakes Michigan and Huron to Lake St. Clair-Lake Erie, appears to bear much of the blame. The three most possible causes are the erosion of the St. Clair River bed, relative change in net basin supply (NBS), and differential glacial rebound. Dredging and erosion so induced might have changed the river conveyance. In this paper, only sediment erosion will be considered. Among many other things, sand/gravel mining, sediment supply into the St. Clair River, and changes of the river cross section at some critical points may have affected the conveyance. In this study, a two-dimensional numerical code, HydroSed2D, will be used to investigate whether the St. Clair River is still eroding under current flow conditions. HydroSed2D is a two-dimensional depth-averaged hydrodynamic code with a sediment transport module. It is based on the shallow water equations. This code has been used in many engineering applications. Bathymetry data is compiled from different sources (single beam and multi-beam echo sound surveys). Sediment size distribution information is from the image analysis of under water videos. With the bed shear stresses results, the possibility of sediment movement in the St. Clair River is analyzed.

Many rivers in Taiwan have steep slopes, are subject to typhoon induced flood flows, and contain soft bedrock that is weak and exposed at many locations. Soft bedrock erosion, therefore, is an important river process to consider for river projects. In this study, the bedrock erosion modeling is reviewed and a specific model is proposed by combining two existing models. The proposed bedrock erosion model is then incorporated into a two-dimensional mobile-bed model, SRH-2D. The model is used to simulate the bedrock erosion downstream of the Chi-Chi Weir on the Choshui River. A calibration study is carried out first to determine the appropriate values of the model parameters over a two and a half year period. The calibrated model is then used to predict bedrock erosion of the same reach for the next two years. Comparisons of both the calibration and verification model results with measured data lead to an assessment of the model performance. The study reports the current progress of bedrock erosion modeling; it also points to limitations and potential future research needs.

The coastal wetlands of Louisiana have been adversely impacted by levees and other anthropogenic changes along the Mississippi River (MR) which have reduced the sediment delivery to the coast. One and three dimensional models of hydrodynamics and sediment transport have been implemented to quantify the potential riverine responses to re-connecting the river to the wetlands. The 1-D (HEC-RAS) model predicts riverine and sediment impacts over 475 kilometers and several years. The 3-D model (FVCOM) analyzes complex flows at the local scale near potential diversion sites. The study domain extends from Tarbert Landing to the Gulf of Mexico. The 3-D model was calibrated against field measurements and was able to reproduce the secondary flow at a bend. The hydrodynamics and sediment transport modules of HEC-RAS were also calibrated and showed good agreement with field data. The Engelund-Hansen sediment load model in HEC-RAS gave the best estimate of the bed material load.

The mechanical response of emergent and submerged aquatic vegetation to hydraulic forces has received considerable attention due to its significant implications for channel design, habitat restoration, and water resources management. Vegetation deflection and rupture is a complicated phenomenon due to the complex interacting processes between flow field characteristics, hydraulic forces, vegetation material properties and physiology, and hydraulic roughness. The objectives of this paper are to advance our understanding of vegetation-flow field interactions by providing an analytical technique for investigating vegetation bending under emergent flow conditions. Both static and dynamic formulations of the problem are presented. The analytical methods presented here can serve as the foundation for applied studies to allow vegetation bending and hence dynamic hydraulic roughness in flood risk investigations.

Bioretention cells have gained favor as a stormwater best management practice (BMP) in areas with suburban or moderate urban development. Despite their popularity, the complex interaction between vegetation, hydrology, and treatment efficacy in these systems is generally not well understood. This paper presents preliminary results of a multi-year study of a bioretention cell in Northeastern Kansas. During the study period, stormwater influent and effluent quality and quantity were monitored using autosamplers. Water level in the cell was tracked using a staff gage in conjunction with time-lapse photography. Vegetation sampling was conducted in the spring and fall of each year to determine total plant cover and to assess species diversity. This paper focuses on efforts that are underway to study the variability in vegetation composition on the site using a high-resolution digital elevation model of the cell, coupled with hydrologic modeling. Variables of particular interest are the inundation frequency, duration, and depth at locations throughout the cell. The results presented here are preliminary, and have not been fully calibrated to site observations.

Established in 2005 by the Colorado Legislature, the Water for the 21st Century Act creates an Interbasin Compact Committee and nine Basin Roundtables that provide a permanent forum for broad-based water discussions in the state. With assistance from the Colorado Water Conservation Board (CWCB), the Basin Roundtables are conducting assessments of the environmental and recreational water needs throughout the state in two phases. The first phase was completed during the past 2 years and included a comprehensive stakeholder-driven mapping effort of environmental and recreational "focus areas" throughout Colorado. This phase also included a pilot of the Watershed Flow Evaluation Tool (WFET). WFET is an application of the Ecological Limits of Hydrologic Alteration (ELOHA). This paper describes methods the stakeholder process used in completing the mapping efforts and the results of the WFET pilot.

Water management in the western United States is becoming increasingly sophisticated in order to adhere to complicated physical, legal, and environmental constraints. The desire to improve water accounting techniques requires improved tools for quantifying the components of the water budget with the greatest degrees of uncertainty. For example, conveyance losses attributed to seepage to groundwater and riparian evapotranspiration (ET), can potentially play a substantial role in water accounting. More specifically, the research described in this paper was motivated an intense water accounting scheme being undertaken on the Truckee River in Nevada and California. The Truckee River is one of the most intensely regulated systems in the U.S. and the federal, state, and local authorities are entering into a new era of flow management known as the Truckee River Operations Act (TROA). TROA is designed to add flexibility to water management in the basin, but as a result, requires intense water accounting, which will be achieved by the Federal Water Master using a RiverWare model. One of the stipulations of TROA is the quantification of incremental changes in conveyance losses, due to channel seepage and ET, resulting from changes in streamflow and stage. The objective of the research presented here was to determine if there is a detectable change in riparian phreatophytic ET as a function of river stage. Due to the high degree of uncertainty associated with most ET measuring techniques, riparian ET was monitored for this study using a sap flow technique which is based on an energy balance. Sap flow has been shown to correlate well with individual plant transpiration. Stream stage and local depth to groundwater were also measured using pressure transducers. In order to parse the influence of groundwater depth from meteorological influences, a weather station was deployed to determine reference ET. Our preliminary results indicate that ET is not substantially influenced by depth to groundwater. Fluctuations in ET appear to be more strongly correlated with reference ET conditions. The results are consistent with previous studies that have shown that phreatophytic plants are more strongly impacted by the rate of change of groundwater depth rather than absolute changes. The root architectures of riparian plants, such as willows and cottonwoods, are strongly influenced by historic groundwater conditions and the plants develop major roots in the vicinity of the capillary fringe. Hence, small variations in depth to groundwater within the historical range of root development, as is the case in a highly regulated system like the Truckee River, are not likely to impact plant transpiration rates, as was shown in this study.

For small weir structures, fish often have to rely on drowned conditions to move upstream. A structure is considered drowned when the tail water level rises above the height of the barrier and the barrier becomes submerged. There is surprisingly little data on upstream fish movement across barriers under drowned conditions Important parameters affecting the success of an individual fish moving across a weir include the depth and velocity above the weir under drowned conditions, the head difference across the weir, and the surface roughness and roughness around the edges of the weir. For fish populations, other critical factors are the frequency, duration and timing of drowned flows. There are, thus, two requirements to address the adequacy of a given or proposed weir for upstream fish passage under drowned conditions. Firstly, the hydraulic properties of the drowned weir with respect to the requirements of the target fish species and, secondly, the duration and timing of drowning flows with respect to the timing of migration movements. In this paper a computer program, incorporated in a simple-to-operate spreadsheet, for the determination of the hydraulic characteristics of a drowned weir is described. The program is based on a theoretical analysis of drowned weirs and subsequent extensive verification in laboratory experiments. Some discussion is also provided on the frequency, duration and timing of drowned flows. It is shown that the program is an extremely useful tool in the design and/or assessment of a weir structure for fish passage under drowning conditions.

Water pollution accidents occurred with the rapid economical development in recent years in China. In this study, forecast and early warning system of water pollution accident are constructed based on GIS technology. Hydraulics, water quality model and remote sensing model are used to simulate the transfer of the pollutants, and different projects are compared to remove them. The system integrated spatial database, attribute database, hydraulic model, and water quality model under a user-friendly interface in a GIS environment. System ran in both Client/Server (C/S) and Browser/Server (B/S) platform which focused on model and inquiry respectively. System provided spatial and attribute data inquiry, water quality evaluation, statics, water pollution accident response case management (opening reservoir etc) and 2D and 3D visualization function, and gave assistant information to make decision on water pollution accident response. The study provides an example to predict and control environmental emergencies in China.

Eutrophication is the phenomenon observed in the bodies of reservoirs that receive large influxes of nutrients especially phosphorous. Simulation models have been used as useful tools in the study of TMDL for eutrophication in lakes. In this study, a system dynamics (SD) approach is applied to simulate and analyze phosphorus concentration in the reservoir. It is done via an object-oriented modeling software namely STELLA. The modeling process consists of developing, stock-flow diagrams that consider both inflow and outflow of the reservoir for the phosphorous load. Two main processes in the reservoir phosphorous model are sedimentation and release between the sediment at the button and the reservoir water body. Model calibration and validation was done for a 41 month period data The model has been applied to determine TMDL in monthly scale for the allowable load input to the Satarkhan reservoir in Northwestern part of Iran. Results indicated the significant value of the model in the TMDL application.

Stormwater phosphorus (P) removal has received growing regulations in the last two decades. A regulatory guideline of 50–65% total phosphorus (TP) removal has been commonly implemented. However, many past BMP studies showed that it was difficult to consistently achieve TP removal rates in excess of 40%. Numerous treatment practices, even though sporadically achieving high initial TP removal rates, continued to release TP into effluent afterwards. To achieve successful implementation, characteristics of filtration media such as adsorption capacity, gradation, surface area, durability, toxicity, cost, environmentally friendly manufacturing process, easiness of maintenance, and convenience of disposal are all critical parameters. To develop a media that meets these requirements, hundreds of formulations were evaluated. The end result is an adsorptive light weight engineered media (EM). It is designed to efficiently remove TP from stormwater by adsorption of dissolved P and filtration of particulate P simultaneously. Bench scale evaluation results using simulated stormwater demonstrated 50% removal of 0.5 mg/L dissolve P solution for the first 1000 empty bed volumes (EBVs) when operating at 260 cm/hr. By comparison, zeolite commonly employed in stormwater treatment could only treat few dozens of EBVs under the same conditions before exhausted. In the subsequent field trials using real stormwater runoff, over 70% of influent TP was removed for two events with event mean concentrations (EMCs) of influent TP higher than 0.075 mg/L. In another event, influent TP was non-detectable (< 0.02 mg/L) and so did the effluent TP. No release of TP from the used media indicated the strong affinity sites provided by the adsorptive EM. More field scale testing is ongoing. In brief, all the available results show that EM promises to efficiently remove stormwater phosphorus.

In this paper we describe the Ohio River Community HEC-RAS Model (Model) and include some preliminary results. The Model is a cooperative effort involving the U.S. National Weather Service (NWS), Ohio River Forecast Center (OHRFC) and the U.S. Army Corps of Engineers (USACE), Great Lakes and Ohio River Division (LRD), Water Management Division. Initial planning to develop a community unsteady flow model for the mainstem of the Ohio River using the USASE HEC-RAS model began in late 2006. The purpose of collaborating on the development of the joint model was that, when completed, both agencies could independently use the model for operational/forecast purposes, yet share in the development effort, which is substantial. While the Model is now complete, continued enhancements and extensions are anticipated, such as modeling reaches of major tributaries like the Cumberland and Kanawha Rivers. Subsequent changes by one agency will be passed back to the other agency in order to maintain consistency, so that future development can be easily shared. The scope of the modeling effort includes 20 locks and dams on the Ohio River, with storage areas and lateral structures such as levees, as well as bridges. The Model is comprised of over 2800 cross-sections, spanning approximately 1300 miles of modeled reach. The downstream boundaries are Chester, IL for the upstream portion on the Mississippi River and Caruthersville, MO for the downstream portion on the Mississippi River. The upstream boundaries include Braddock Lock and Dam, WV on the Monongahela River and Natrona, PA on the Allegheny River. The Model requires lateral and tributary inflows and is run in real-time; for the OHRFC the lateral and tributary inflows result from runoff produced by both observed and forecasted precipitation. Laterally, Model cross-sections extend to the 500-year floodplain limits, except for Mississippi River reaches that only extend to the USACE levees. Model development involved substantial geographic information system (GIS) data preparation to obtain consistent vertical and horizontal datums between the various data sets used. Digital elevation model (DEM) data sources included U.S. Geological Survey (USGS) 10 meter DEM, and Lidar data provided by the USACE, and local and state agencies. Bathymetric and in-channel cross- section data were provided by the USACE. Every effort was made to include the best available data, and. it is anticipated that substantial improvements will be made in the future by the use of higher resolution data sets.

Flash floods, the most common type of flooding in Yemen, have killed many people in Sana'a (the capital of Yemen) in the past decade. A natural disaster risk evaluation, funded by the World Bank, Global Facility for Disaster Reduction and Reconstruction was conducted in Sana'a to identify the main sources of losses from natural disasters such as floods and landslides and to develop an analysis of flood risk exposure and financial response capacity for the city. Climate change and the rapid urban development of Sana'a has led to an increase in flood hazards for two main reasons, changes in land use, and the increased presence of people and buildings in flood prone areas. The major stormwater channel in Sana'a, which runs through the middle of the city and next to the old historic city, also serves as a major transportation route. When a flash flood occurs, the stormwater channel is suddenly flooded causing vehicles to be trapped and sometimes swept away, putting lives at risk. No mechanism is currently in place to prevent vehicles or people from using the channel during extreme flood events. Comprehensive hydrologic and hydraulic modeling of the Sana'a Basin was conducted to support a flood hazard analysis that quantifies the extent and depth of flooding throughout the flood prone areas for a range of flood frequency events. The hydraulic analysis was performed to create water surface profiles and develop floodplains for extreme events within the city of Sana'a. HEC-RAS was used to model the hydraulic response of the stream network to frequency flows. The HEC-GeoRAS tool was used to expedite parameter input and mapping processes. Significant challenges were addressed during the modeling process due to the lack of accurate digital elevation data, few historical flood data, and major changes in the land use from rapid urbanization. The floodplains were mapped along the major stormwater channel identifying the flood hazard areas in Sana'a during extreme events. This information will be used to calculate infrastructure and economic losses, identify mitigation projects and develop a flood warning system for flash floods in Sana'a.

The cost analysis of water systems planning determines if potential solutions provide a basis of comparison and selection between various alternatives for ranking different water development and management policies. Based upon this analysis, the sensitivity of the project outputs can be estimated and the decisions on the use of water resources and economic conditions can be predicted. In this paper, we present an optimization model to minimize the costs for obtaining water needs of different users. The proposed model takes into account the water needs of the users, hydraulics losses during water distribution and capacities of the supply sources, water pumps and water storages and costs to obtain water. Model constraints include demands, limitations in the capacity of the various water sources and legal and structural specifications that must be followed in terms of water allocation. For illustration purposes, the model is applied to a simple case study. However, since our model is generic it can be applied to any water system schemes.

There are an estimated 150,000 culverts in the United States that convey water from streams and creeks underneath our vast transportation network. These culverts were originally designed for hydraulic conveyance without consideration given to the varied aquatic ecology that was present, including fish. Each of these culverts represents a potential migration barrier for fish. The accepted design of culverts uses calculations based on Manning's roughness coefficients at full capacity flow. Manning's roughness in pipes has long been known to vary with depth (Chow 1959). There have been a handful of studies that have been conducted on the variation of Manning's roughness coefficient with depth inside pipes (Mills 1924, Camp 1946, Pomeroy 1967, and Fukuchi 2006). A culvert having partially full flow is the most common culvert condition and consequently represents the most likely flow that fish experience during migration. Unfortunately at these low flow depths the results of roughness experiments are contradictory. For instance, at flow depths less than 20% of the pipe diameter, Pomeroy 1967 found roughness coefficients less than full pipe roughness while Camp reports roughness coefficients greater than full pipe roughness. Over much of the flow depth there is 20% to 30% deviation in Manning's roughness which directly relates to differences in predicted velocity. Drag on a fish body is a function of velocity squared while the power required for swimming is a function of velocity to the third power. These relations indicate that the moderate errors in Manning's roughness that have been reported will have large effects on the predicted fish passage potential of a culvert. Further, existing literature uses data obtained from pipes having diameters 12 inches or less made from materials of either vitrified clay, concrete, or galvanized steel. According to the Ohio Department of Transportation, the most common diameters of culverts range from 12 inches to 10 feet and are comprised of corrugated steel, corrugated plastic or concrete. The purpose of this research is to examine pipe roughness in culverts at partially full conditions for the materials and diameters most commonly used in practice today in order to increase the efficacy of fish passage design. The paper will include a literature review and discussion of the previous work on this problem as it pertains to fish passage. Furthermore, in order to fill in gaps and clarify inconsistencies with the data, preliminary results from a culvert roughness study will be included.

The River Shrimp, Cryphiops Caementarius, is a crustacean that lives between parallels 10° S and 30°S in rivers and ocean estuaries of the Western Slope of the Andes. As they grow, they migrate upstream, mate, and females whose eggs are fertilized move downstream to the river estuary and the Pacific Ocean. Several intakes have been built by the Ministry of Agriculture along the Cañete River. This species population has been observed to decline in several coastal rivers of Peru. This investigation was aimed to investigate whether intakes have a deleterious effect on the shrimp population, taking into account that other factors may also have an important effect. Extreme environmental conditions in which shrimp may survive have also been documented in laboratory experiments. The main objective of these research programs was to study the feasibility of the reproduction of the Cryphiops Caementarius in captivity with economic purposes. Data gathered by consulting firms show that in actuality the water physical and chemical parameters may not pose a significant threat to the reproduction of the shrimp. Field observations made during the course of this investigation, reports written by a local's fishermen association and field interviews have shown evidence that intake structures have a harmful effect on the shrimp population. It has been concluded that river intakes cause a barrier effect that prevents the smaller individuals from moving upstream. Preliminary remedial solutions have been proposed in this paper based on field observations,

This report is an overview of the models and guidance used to design navigation improvements for the approach to Lock 22. Two major issues for L&D 22 are hazardous outdraft currents and barge traffic delays. The frequent nature and severity of these problems has caused a desire to improve the safety and efficiency of the system. As a result, many hydraulic engineering (and other) studies have been conducted since the early 1990's.

Hurricane Katrina raised public awareness of the vulnerability of our nation's levees to failure, due either to deficiencies or an event exceeding design capacity. Prior to Katrina, however, the Federal Emergency Management Agency (FEMA) formulated a program to better understand the location and condition of levee systems currently accredited as providing protection on the Flood Insurance Rate Maps (FIRMs). Following the formation of a Levee Coordination Committee, FEMA issued Procedure Memorandum 34 (PM 34) on August 22, 2005, just prior to Katrina (August 29, 2005), as an interim guidance on the levee policy. PM 34 established guidance for inventorying levee systems and establishing levee review protocol. As part of the levee review protocol, FEMA would provide an inventory of the levee systems. However, the owning agency requesting accreditation of the levee on the FEMA flood maps would be responsible for providing the levee certification and supporting analyses. In September 2007, the United States Army Corps of Engineers (USACE) released a draft Engineering Technical Letter (ETL) 1110-2-570, "Certification of Levee Systems for the National Flood Insurance Program (NFIP)" (USACE, 2007), which provides technical procedures for levee certification under the National Flood Insurance Program (NFIP). In September 2008, ETL 1110-2-570 was superseded by EC 1110-2-6067 (USACE, 2008). To allow more time for the agency to complete levee certifications, FEMA issued PM 43 on September 25, 2006 allowing for the establishment of Provisionally Accredited Levees (PALs) whereby additional time is given to submit certification information. During that time, the levee can be shown on the FEMA flood maps as providing protection on a provisional basis. All existing levees accredited by FEMA as providing protection against a flood having a 1% chance of being equaled or exceeded in any given year (i.e. 1% annual chance, 100-year, or Base flood) must be certified or loose accreditation. Certifying the flood protection system requires conformance to 44 CFR 65.10 of the NFIP Regulations, "Mapping of Areas Protected by Levee Systems" (CFR 65.10, 1986), and involves the evaluation of several major components, including: (1) Freeboard; (2) Closures; (3) Embankment Protection; (4) Embankment and Foundation Stability (Stability and Seepage); (5) Settlement; (6) Interior Drainage; and (7) Operations and Maintenance. Failure to submit requested documentation in the required timeframe, 2-years from the date of the PAL agreement, or studies indicate the system does not meet the requirements of CFR 65.10 results in previously protected areas being shown within the 100-year floodplain on FEMA's FIRMs. Refer to Figure 1 and Figure 2 for example FIRMs with and without accreditation, respectively. The same CFR 65.10 requirements apply to floodwalls. This paper addresses an overview of the hydrologic/hydraulic requirements for certification, including freeboard, uncertainty, and interior drainage.

Design of wastewater treatment facilities often entails mixing of various flow streams and chemicals. Adequate mixing can be a critical component of the overall treatment plant performance. The required mixing can be accomplished with mechanical mixers but mechanical mixers can be expensive to install and operate. An alternative to mechanical mixers is to install structural features that create turbulence and promote the mixing of flow streams and chemicals. However, it can be very difficult to evaluate the effectiveness of this type of passive mixing to achieve the desired goal. In addition, these structural features will create headloss which may increase the plant power requirements. Therefore, it is important to evaluate the complex hydraulics around these structural features to develop a cost effective design. This paper presents a case study to illustrate how CFD analysis can be used to assist with the evaluation and design of channel mixing features. It will illustrate the flow characteristics of several mixing structures and compare their mixing and headloss characteristics. It will demonstrate how the insights gained from CFD analysis can be useful in the practical design of a wastewater treatment plant mixing channel.

The use of formed suction inlets (FSI) on large vertical pumps has been common in the flood control field for many years. The US Army Corps of Engineers Type 10 inlet is a common example that has been used extensively throughout the south eastern United States for flood control as well as on numerous projects as part of the broader Everglades Restoration Project. The inlet is gaining popularity in higher head applications such as circulating water system for power plants. Extensive design development and research in the performance of the Type 10 Inlet has been undertaken over the years. However, nearly all of this research has focused on Type 10 inlets for flood control applications which typically utilize axial flow pumps. Recently the Type 10 has been used or considered for a wider variety of projects including cooling water applications which typically utilize a radial or mixed flow pump. This type of pump typically has a smaller throat diameter than an equivalent capacity axial flow pump. Given that the design of the FSI is based on the throat diameter there is some question regarding the impact of the smaller resulting FSI design and corresponding increase in velocity. In several recent applications of Type 10 inlets installed on mixed flow pumps the inlet was designed for a larger pump impeller inlet diameter to increase the size of the FSI and reduce the inlet velocity. A larger than normal reducing cone was then used to transition into the smaller pump throat. This paper presents a comparison of inlet conditions for a variety of mixed flow and flood control applications which were evaluated during physical model studies. Several different "inlet eye diameter" to flow rate or velocity ratios are investigated with an attempt to identify the ideal ratio to use for determining an appropriate diameter for the FSI design. These results can be used by design engineers when considering FSI for mixed flow pump applications and reduce the likelihood of inlet related problems associated with increased inlet velocities.

Water seepage is a common problem in most of dam sites, in which the impounded water finds the escape routes with least resistance through the dam body and foundation. Typically, grid-based approaches have been frequently employed to tackle this problem. However, generation of appropriate grid is a very burdensome and time-consuming task specifically in problems with complex geometry. To overcome this problem, this paper employs Lagrangian-based smoothed particle hydrodynamics (SPH) meshless method to analyze the seepage through dam foundation. The SPH method is applied to Chapar-Abad Dam located in northwest of Iran. The presence of thick alluvium deposits with different permeability coefficients demonstrates possible seepage problems. Although implementation of the SPH method in much easier than grid-based methods, the results of this method are in good agreement with those of a frequently used grid-based method, i.e. Finite Elements Method (FEM). To attain a general vision of seepage flow beneath the dam, the seepage maps obtained from both SPH and FEM methods are shown separately and the results are compared. Conclusively, the results demonstrate the practicability and performance of SPH method in analysis of seepage specifically for the problems with complex geometry.

Limited information pertaining to sizing air vents for low-level outlet works, specific to geometries consistent with small-medium size embankment dams, which feature an included slide gate at the pipe inlet, is available in the literature. Current air vent sizing methodologies available in the literature are specific to large-dam outlet geometries. Air venting is used to increase the pressure downstream of the slide gate, which reduces the risk of cavitation. Air demand is related to the water flow rate through the outlet. In the absence of an independent flow measurement facility (e.g., a weir or flume installed in the downstream discharge channel), the water discharge through a low-level outlet works could be estimated using slide gate discharge coefficient and an appropriate driving head. No published discharge coefficient data for included slide gates were found in the literature. A lab-scale model of a low-level outlet works was constructed and tested in the lab to determine vented and non-vented square slide gate discharge coefficient data as a function of gate opening and driving head. Air demand data were also collected. Designer can use the Cd and air demand data as a guide for sizing air vents for small to medium size embankment dams.

This study has been conducted to optimize the energy dissipation works for the Nai Gaj dam spillway of a multipurpose earthfill dam (estimated cost of Rs 6.23 billions) proposed on Gaj River in Western Sindh. It covers the design of technically viable options of energy dissipaters, determination of spillway quantities for all options, determination of cost for each option, comparison of costs and selection of the one with the lowest cost. Options of energy dissipaters were considered and optimized, keeping in view the available data. Among the options, Impact Type Basin was rejected due to discharge limitation and very high expected velocity at the toe (and the high value of Froude number) while the other options of energy dissipation using Stilling Basins, USBR Type II (both one step and two steps), Roller Bucket and Flip Bucket were considered and designed. For the Stilling Basin, USBR Type II option, two further options were worked out i.e. to dissipate energy in a single step (with one stilling basin) and in two steps (with two stilling basins). Among these, the latter proved to be cost effective due to significant less excavation. The option of Roller Bucket design was restricted due to insufficient tail water depth. [To make this option applicable, a hump was created downstream of the bucket to raise water level to a minimum required level]. Another option was to flip the incoming discharge at the toe of the spillway and the creation of a plunge pool. Since the spillway foundation was permeable therefore chances of bed scouring were there, thus endangering the dam body and limiting the use of Flip Bucket (and plunge pool). Cost analysis and other technical parameters showed that the option of Stilling Basin Type II (USBR type II), with two steps (i.e. two stilling basins), is the optimal choice for energy dissipation of Nai Gaj Dam's spillway.

The Cache Creek Settling Basin is located two miles east of Woodland, California and was constructed to preserve the floodway capacity of the Yolo Bypass by entrapping sediment. Cache Creek is the main source of mercury entering the San Francisco Bay-Delta. Entrapping sediment helps to entrap mercury thus acting to protect the aquatic life of the San Francisco Bay-Delta. A 2-dimensional hydraulic and sediment transport model is under development. The model modules for sediment transport and hydrodynamic modeling will be coupled under historical flow conditions. Preliminary results are presented herein.

The hydrologic cycle is very sensitive to climatologic factors. Therefore there is concern related to the effects a changing global climate will have on water resources. Many recent studies have been undertaken to address the potential effects of climate change on water resources; however little research has been undertaken to specifically address the effects on sediment transport. Global climate change is projected to have differing effects on regional climatologic factors. Studies have indicated the likelihood of an increase in the frequency of heavy precipitation events in Michigan. This possibility is of concern due to the sometimes adverse consequences of such extreme events. One of the many factors that would be affected by an increase in the frequency of such events is the quantity of sediment transport in regional rivers. The effects of climate change are expected to manifest themselves differently in different regions. This is due to the complex climatologic interactions that contribute to each regional climate. Literature is reviewed in this paper to set the stage for future research regarding climate change, specifically precipitation change, effects on sediment transport, with an emphasis on Michigan Rivers.

In 2001, the New York State Siting Commission for Public Utilities scheduled Hearings on an application for the use of ground water and surface water for power generation in New York that would affect the drinking water supply in northeast New Jersey. The applicant proposed construction and operation of a 1,100 megawatt natural gas-fired combined cycle combustion turbine electric generating station. The proposed 1,100 megawatt station was to serve peak electric demands in a portion of the grid serving metropolitan New York. This paper will compare and contrast the technical, legal and institutional analysis of ground and surface water interactions. In addition, an historic perspective on the calculation of ground and surface water interactions to determine drought severity will be taken from the Report on Water-Supply, Water-Power, the Flow of Streams and Attendant Phenomena dated 1894 prepared for the New Jersey State Geologist by Cornelius Clarkson Vermeule, Consulting Engineer. In that text, now available online through Google books, the author noted how precipitation and cumulative precipitation deficits could determine groundwater contribution to surface water baseflow.

Research currently being conducted at Missouri University of Science and Technology involves using a traditionally high pressure water jets in a new and innovative manner to inject adsorptive and dechlorinating amendments at varying depths in contaminated waterways. Previously published works identify Zero Valent Iron (ZVI) and Powdered Activated Carbon (PAC) as effective means of remediating contaminated sediments and groundwater. While the investigations of both amendments are within the breath of this project, this paper will focus primarily on the placement technologies and the analysis of PAC. A laboratory testing platform, novel amendment jetting, and nozzle designs were all developed to inject amendments into sediment beds. Analytical testing was conducted to examine the reliability in detecting amendment concentrations in sediments to evaluate distribution. The results obtained from this portion of testing, while not extensive, have yielded an effective delivery mechanism and reliable data acquisition system. Ultimately, the goal of this project is to remediate sites via targeted amendment delivery, while minimizing re-suspension, and minimizing damage to benthic biotia.

This paper presents a laboratory study that evaluates the relationship between suspended sediment concentration (SSC) and the acoustic backscatter strength recorded by a Nortek Vector velocimeter for different natural and commercial sediments. Tests were conducted in a tank using kaolinite and three other types of natural mud taken from the Houston Ship Channel. SSCs ranged from 0.001 to 7 g/l for kaolinite and 3.5 g/l for natural sediments. Results show two regions of response in the relationship between the acoustic return and the SSC. The first region was for concentrations less than 3.2 g/l. In this region, the strength of the return signal is linearly related to the logarithm of concentration with a constant positive slope. Above this concentration, the strength of the acoustic return decreases with increased concentration. The study examines the difference in these basic trends among the different sediment types.

Everglades are a critical component of the regional hydrological cycle in South Florida. Anthropogenic activities in this region have deteriorated the wetland ecosystem and efforts have been made to restore and preserve it. Seasonal and interannual changes in water stage result in saltwater intrusion and inhibit ecosystem conservation measures. Hence, there is a need to monitor water stage in wetlands. Microwave remote sensing with its sensitivity to surface characteristics provides an opportunity to measure changes in water stage from space. Spaceborne remotely sensed images can provide a comprehensive spatio-temporal distribution of water stage over an area thereby eliminating the need to monitor water stage separately at each measurement site. This research relates water stage measurements (w_s) to Tropical Rainfall Measuring Mission Precipitation Radar backscatter (σ°). σ° response to partially exposed vegetation is used as the basis of the model. Variations in the water depth change the amount of exposed vegetation canopy that is reflected in the σ° measurements. An empirical linear model is developed that expresses w_s in terms of σ°. The impact of vegetation on the model is studied by examining model performance over various landcovers. The w_s model is applied to stage data on sites operated by South Florida Water Management District. Eleven year data (1998 to 2008) is used for this research. The model is calibrated using 75% of the time period of data to estimate model parameters. The model is validated using the remaining 25% of the time period. The estimated water stage measurements from the model are compared with observed measurements over different landcovers. The model performance is assessed by comparing correlation coefficient (R), root mean square error (rmse), and mean absolute error (mae) between observed and modeled water stage measurements. The model works reasonably well in the regions with tree heights greater than 5 m such as deciduous forest (R=0.58, rmse=0.58 ft, mae=0.45 ft), mixed forest (R=0.61, rmse=0.78 ft, mae=0.57 ft), and woodlands (R=0.56, rmse=0.65 ft, mae=0.54 ft). Other low lying landcovers such as cropland (R=0.27, rmse=0.63 ft, mae=0.48 ft) and closed shrubland (R=0.33, rmse=0.56 ft, mae= 0.43 ft) do not show significant performance of the model. This is because the vegetation in croplands and closed shrubland are submerged under water for most part of the year. The incident microwave radiations get specularly reflected from the water surface resulting in lesser backscatter. On the other hand, in areas with tall vegetation, the incident radiations get backscattered from the vegetation above the water surface exhibiting distinct response as a result of the amount of submergence. The modeled values of water stage compare well with the observed water stage in areas with tall vegetation. Thus microwave remote sensing can provide a comprehensive spatio-temporal distribution of water stage. This research provides a new insight into measurement of water stage using spaceborne remote sensing techniques.

Scour around various structures obstructing flow in an open channel is a common problem; therefore a better understanding of how turbulent flow affects sediment transport is needed. Additionally, is it the mean flow or the turbulence properties that are more important in contributing to bed shear stress? To this end, an experimental study was conducted in a fixed-bed flume containing a series of dikes. Turbulence intensities and Reynold's stresses were calculated from 3-D velocity measurements gathered with a microADV. Results showed that the maximum shear stress was nearly 12–20 times that of the approach flow, while maximum turbulence intensities were about 3–5 times those of the incoming flow. Highest magnitudes of both were seen at the tip of the second dike in the three-dike series. The mean velocity appeared to have no relation to the formation of scour near the tips of the dikes but the turbulence intensities did.

Three-dimensional turbulent flow field was measured around an experimental spur dike by using a micro-acoustic Doppler velocimeter. Time fractions of turbulent burst events including outward interaction, ejection, inward interaction, and sweep were analyzed in each quadrant at the neighbor of the dike before and after the formation of scour hole. Over 80% of burst events near the bed have lower-order of magnitudes for both flat and scoured bed surfaces. Ejections and sweeps are prevalent before the local scour was initiated, and then outward interactions and sweeps are dominant after the equilibrium scour hole was formed. In the scour zone turbulence intensity in the vertical direction has reduced significantly, while it increased in the horizontal direction and facilitated bed load sediment transport. Conditional Reynolds stresses and high-order moments of turbulent velocities were analyzed along the thalweg. The magnitudes of u'-w' and u'-v' pairs were much greater than those of v'-w' pair in the scour zone. Ejections and sweeps were the higher order events contributing to the Reynolds stresses. Since sediment entrainment and transport are closely associated with turbulent bursts near bed, the contributions of high-order events to sediment motion greatly depend on localized turbulence intensity.

This paper summarizes the investigation of a failure of a gate-controlled culvert structure made of precast concrete segments while operating under high flow. Seepage underneath the culvert and the complex hydrodynamic conditions induced by the flow in the culvert were studied separately to ascertain their relevance in the structure's failure. Seepage was studied by the Analytic Element Method including estimates of uncertainties in model output by Predictive Analysis techniques. The flow structure in the culvert (velocity and pressure fields) was modeled by Reynolds-Averaged Navier-Stokes (RANS) while pressure fluctuations were modeled using Detached Eddy Simulations (DES). Results suggest that the seals used at the culvert segments failed from the combined effect of pore pressure from seepage flow combined with negative pressure fluctuations within the culvert barrel induced by the flow behind the partly open gate. After seal failure, negative pressures promoted high exit-seepage gradients at the joints that induced piping and erosion of the foundation and ultimately resulted in dislodgement of the culvert segments.

Dam removal is becoming more common in the United States as dams age and environmental concerns increase. Sediment management is an important part of many dam removal projects, but there are no commonly accepted methods to assess the level of risk associated with sediment stored behind dams. Therefore, the interagency Subcommittee on Sedimentation (SOS) is sponsoring the development of a decision framework for assessing sediment-related effects from dam removals. The decision framework provides guidance on the level of sediment data collection, analysis, and modeling needed for reservoir sediment management. The framework is based on criteria which scale the characteristics of the reservoir sediment to sediment characteristics of the river on which the reservoir is located. To assist with the framework development, workshops of invited technical experts from around the United States were convened October 2008 in Portland, Oregon and October 2009 in State College, Pennsylvania. The decision framework developed at these workshops is currently being validated with actual dam-removal case studies from across the United States including small, medium, and large reservoir sediment volumes. This paper provides the latest thinking on key components of the guidelines. The paper represents contributions from over 26 entities who have participated in the development of the guidelines. After completion of the case study application, the framework will be finalized and published.

Dam removal is crucial for reconnecting river habitats, restoring passage of fish and other aquatic organisms, and restoring the free flow of water and sediment. However, removal of obsolete dams is often resisted due to concerns of releasing sediment and initiating channel instability. Two dams on the Musconetcong River in northern New Jersey have been removed by Princeton Hydro LLC in 2008 and 2009 as part of a watershed-wide effort to remove or breach all major obstructions to restore the river to its original free-flowing state. The two dams were consecutively situated 0.6 miles apart and their removals provided lessons in design and construction as well as offered an opportunity to study the geomorphic response in the form of bed elevation changes and sediment size through pre- and post-removal monitoring. The Musconetcong River, within the Delaware River watershed, is 89 km long and has a watershed of approximately 400 km². The watershed has mostly rural (forest and agriculture) land use with a few small towns, the largest being Hackettstown (population ~10,000). The Musconetcong flows southwest and is predominantly an alluvial stream with mostly shale and carbonate bedrock lithologies (Drake et al., 1996). The importance of measuring, predicting, and mitigating the effects of these dam removals is augmented by 24 miles of the Musconetcong River being federally designated as "National Wild and Scenic" in 2006 (Musconetcong Advisory Committee, 2003). For the removal of the downstream dam, the permitted engineering design called for the installation of boulder rock vanes that would maintain a low, in-stream, grade-control to stabilize some of the sediment, allow fish passage, direct flow away from downstream bridge abutments, and blend in with the character of the waterway. Unforeseen conditions that arose during construction necessitated in-field adjustments, or adaptive management. The dam structure itself was notched weeks prior to the start of construction to allow for partial dewatering of the impoundment. Due to downcutting and channel formation, this process drastically altered upstream bed elevations, such that the proposed design was no longer appropriate. Through collaboration with NJDEP Dam Safety and other project partners, the in-field redesign of not only the elevations, but the configuration and layout of the weir, was crucial to moving the project forward. Ultimately, two boulder rock vanes were installed to maintain an in-channel grade control to limit channel incision and retain some of the impounded sediments, while allowing for fish passage and directing flow away from abutments of a downstream bridge. In the course of construction, sediment was managed in several ways. First, some impounded sediments were permitted to migrate downstream after notching the dam to dewater the impoundment. Second, loose fine sediments (dominated by silt and sand) were excavated from the channel center and placed on the channel margins during the installation of the boulder rock vanes. Sediments were excavated to the approximate depth of the original stream bottom where highly resistant, consolidated layers were exposed to serve as a solid foundation for the footer stones of the boulder rock vane. These design details are important in understanding initial local patterns of erosion and deposition and may be important in interpreting the long-term geomorphic response of the reach. The upstream dam was crudely constructed of concrete poured over a base of river cobbles most likely gathered from the impounded reach. The impoundment was created to provide a swimming area and beach, which was periodically enhanced with imported sand. The structure had two 36-inch (approx) concrete culverts on the right and left sides of the channel that were set nearly flush to the riverbed. As a result, the impoundment was limited in extent, contained entirely within the river channel and sediments had only accumulated in the center of the channel. Over-topping flows had caused a bank failure on river right of the structure. Concerns of project partners and regulators varied widely regarding the fate of impounded sediments, the risk of channel instability and the need for in-stream grade control structures. After much discussion, the final design avoided unnecessary and costly in-stream structures and allowed for gradual geomorphic adjustment. Permits required the rebuilding of the eroded bank and placement of cobbles and boulders in the channel. To minimize the use of imported materials, the bank was built-out with cobbles from the dam and impounded sediments immediately upstream of the dam. Initial geomorphic surveys of the riverbed in the vicinity of and between the two dams have shown areas of erosion and deposition. These surveys have established a set of control points along the river channel between the two dams, and confirm the downstream movement of a sediment plume and localized areas of erosion. At the upstream dam, comparisons pre- and post-dam removal surveys show greater than 100 cubic meters of sediment being both eroded and deposited within the site. Most but not all of the erosion occurred around the newly exposed sediment bar upstream of the former dam, where the thalweg has reestablished itself following the dam's removal. Areas that were excavated during removal have experienced deposition. Most of the deposition occurred downstream and on the left-hand bank. Due to the two low flow culverts in the former dam, a mid-channel sediment bar remains. At the downstream dam site, erosion has removed up to 1.1 m of sediment from the bed in places while depositing up to 0.5 m sediment in others. As sediment from the former impoundment migrated through the project site, areas excavated during the removal became areas of deposition following the removal, and; alternately, areas in the channel margins where sediments were placed experienced gradual erosion. Grain size analysis shows a coarsening of the riverbed over the first nine months since removal. Grain size analyses were done upstream and downstream of the dam sites as well as at two locations between the sites. Wolman pebble counts (Wolman, 1954) were completed using the random walk method at each of the six sites. The largest change in grain sizes at the four sites occurred upstream of the downstream dam site, where there was a significant coarsening of the sediment from October 2008 to June 2009. This has most likely occurred from the increase in energy upstream of the dam post-removal, which has transported many of the fine-grained sediments downstream. Downstream of this dam site sediment size has not significantly changed, suggesting that the fine sediments have been transported downstream far enough to leave the site. Surveys of the channel thalweg above and below both dams also show a pulse of sediment migrating slowing from the uppermost impoundment areas. Long-term monitoring of the channel thalweg may reveal reach-level changes in channel slope.

Hydrodynamic models are often used to reduce uncertainty regarding the outcomes of dam removal, though the accuracy of these models is not regularly evaluated post-removal. With the goal of improving understanding on the accuracy and limitations of making predictions of sediment dynamics following dam removal, we compare predicted and observed sediment erosion and deposition in the reservoir and downstream for the Chiloquin Dam removal. Results from a 1D (HEC-RAS) hydraulic and sediment transport analysis (Yang equation) are compared to pre- and post-removal bathymetric and sediment surveys. Observed bathymetric changes indicate minimal response in both the reservoir and the downstream reaches to the removal, due in part to the low water year and the low volume of sediment stored in the reservoir following drawdown. Model simulations overpredicted erosion in the reservoir and downstream relative to what was observed, likely due to a combination of limited field documentation of resistant hardpan and to issues in model stability. Magnitude and potential sources of error are presented and suggestions are made regarding data needs and potential modeling approaches in future dam removal studies.

The conventional paradigm of dam removal includes an expectation of substantial sediment releases from impoundment storage accompanied by problematic downstream flushing transport and deposition. This expectation is largely based on the River Continuum Concept (RCC) model of streams. However, the pre-dam longitudinal profile of many headwater streams is not that of the stereotypical RCC continuously steep gradient, but rather a more stepped profile including high gradient transport-regime reaches interrupted by lower gradient depositional reaches. In fact, headwater stream systems are frequently punctuated by low gradient, wetland or wet meadow reaches produced by a variety of geologic controls. Modern impoundments now are emplaced within this discontinuous, stepped, longitudinal gradient of erosion-resistant transport reaches and low gradient depositional reaches, and the risks associated with sediment releases from dam removals are minimized by the downstream presence of depositional reaches capable of receiving and storing sediment released from upstream. Furthermore, it is quite likely that many headwater dams were constructed at pre-existing depositional reaches, creating the likely scenario that the impoundment sediments would be largely stable upon dam removal. In regions where these conditions are present, significant costs and delays associated with unnecessary sediment stabilization and or sediment removal are preventing the timely restoration of our headwater systems.

Dams have multiple negative impacts on freshwater mussel populations, and dam removals are sometimes partly justified by expected long-term benefits to mussel communities. However, dam removal activities can also negatively impact upstream and downstream mussel populations, and it may be necessary to translocate all or selected mussel species from the project area. Quantitative surveys of the project site are usually required to assess the need for translocation activities, and also of potential translocation sites to assess their suitability for long-term mussel survival and reproduction. Planning and executing a translocation project must consider multiple factors, including choice of a translocation site, collection procedures at the project site, details of mussel transport to the translocation site, timing of mussel breeding, water and air temperatures, and post-translocation monitoring. Selection of an appropriate translocation site is absolutely vital to the success of a translocation project, and factors to consider include proximity and similarity to the project site, sediment stability and quality, existing mussel populations, water quality, and host fish and invasive species presence. A decision tree that outlines the information requirements and recommendations for mussel translocations, which is under consideration by the Department of Interior's multi-agency Subcommittee on Sedimentation, is discussed.

The Big Sunflower River in northwestern Mississippi drains about 8,000 km², is a low-gradient slowly-moving stream, and has historically provided a valuable ecological, navigational and recreational resource. However, present conditions are characterized by depauperate physical habitat, depressed baseflows linked to falling groundwater levels, elevated turbidity, and chronically low dissolved oxygen levels. Eight 200-m long reaches were sampled biannually (spring and fall) for three years. Two reaches were located downstream from major weirs; three reaches were located in a channelized reach with a trapezoidal cross-section; and three reaches were in a reach with natural morphology. Fish were collected with boat-mounted electro shockers, and bed material types, water depths, and current velocities were sampled using an acoustic Doppler current profiler. Limited water quality data were collected for comparison with data provided by others. Fish populations appear to be primarily limited by degraded water quality. Low-head weirs support relatively dense and diverse fish assemblages and thus provide local habitat enhancement, but may create stagnant zones upstream due to backwater effects that exacerbate low dissolved oxygen problems.

David Rosgen's methods for river classification, analysis, and restoration design have been utilized to varying extents all over the United States. A growing body of geomorphic data is being collected by individuals trained in Rosgen methodologies. While this information can be extremely valuable for geomorphic analysis, it can be easily misapplied. Rosgen assigns unique definitions to common terms and uses special methods that differ from the definitions and methods used in traditional geomorphology, hydrology and hydraulics. Researchers and agencies using geomorphic data collected by Rosgen-trained surveyors need to understand what those differences are in order to correctly analyze and use the data. This paper explains terms and procedures involved in the reference-reach survey that may be misunderstood. This paper also suggests simple changes to the Rosgen reference-reach survey that will enhance the usability of the results for a broader range of research and practical applications.

River restoration targets are often set according to the River Continuum Concept, in which headwaters are narrow, forested, have coarse substrate, free-flowing water and sediment transport, and connect along a gradient from headwaters to mouth. This investigatory study examines this concept by comparing geometry and substrate of beaver-impounded with non-beaver (NB) headwaters at sixteen river segments in northeastern Connecticut. The beaver-impounded segments were classified in the following categories: valley-wide impoundments (VWI), in-channel dam series (IDS), and downstream of beaver dams (DD). The following width to depth ratios show distinct channels compared with NB: normal IDS (10.8±1.3 vs. 32.9±19.1), bankfull DD (10.2±1.5 vs. 20.0±6.2), and bankfull VWI (52.2±30.2 vs. 20.0±6.2). Additionally, bed substrate distinctions include the following: VWI (100% organic and fines vs. 0%), and IDS and DD (50% and 44% finer than coarse gravel vs. 0%). Given beaver dominance of pre-colonial U.S. river systems, these conditions should be incorporated into restoration targets.

This paper presents a method of natural channel design that incorporates the geomorphic characteristics of a reference reach into an analytical design framework. In this hybrid approach, termed the Analytical Reference Reach (ARR) method, certain characteristics of the design reach are copied or scaled from a reference reach, while other characteristics are obtained analytically. The ARR design method offers several advantages over both the Rosgen reference-reach method and the analytical approach advocated by the U.S. Army Corp of Engineers and the Natural Resources Conservation Service. Its main advantage over the Rosgen design method is that the channel cross-section is sized analytically to convey an appropriate bankfull discharge and the associated bed-sediment load. Its main advantage over the analytical methods is that the reference reach provides guidance for design of channel features such as meander bends and pools that cannot be designed analytically. The design reach is assigned the same sinuosity as the reference reach, which fixes its length and average slope. The bankfull discharge is obtained from a hydraulic analysis of a stable "match reach" on the same stream. Alluvial channels are sized by equating the bankfull bed-load transport capacities of the design reach and the match reach. Threshold channels are sized by scaling the cross-sectional dimensions of the reference reach to convey the desired bankfull capacity at a velocity below the threshold value. Key characteristics of the planform and bottom profile are copied or scaled from the reference reach.

For the past four years, the Town of Castle Rock has been master planning the watersheds within its jurisdiction. As a part of each master planning process, a stream stability analysis was conducted to establish a stable channel grade by reach. Each master planned channel had unique characteristics that affected the stable channel grade including vegetation, soil characteristics and flow regimes. These same characteristics also affected the selection of the stable channel calculation methodology. There are many methodologies to calculate the long-term stable channel grade of a natural channel. Incipient motion of the bed material present in the channel is the basis for most of the commonly used methods of stream stability analysis. The methods include the permissible velocity method, permissible shear stress method and sediment transport equilibrium methodology. The long-term stable channel grades within the Town of Castle Rock were calculated for each channel utilizing different methodologies depending on the fluvial geomorphology and flow regime of the channels. As might be expected, the results of the analyses have varied based on local channel conditions. Due to the various methodologies and results obtained during the long-term stream stability analysis, a technique for the calculation of long-term stable channel grades that would be consistent for all Master Plans and could be quickly employed with a minimum of data gathered from online sources and field observations needed to be developed. The selected analysis technique identified conditions related to flow rate, regime and soil types to predict stable channel grades. This allowed the identification of required stream stabilization infrastructure while managing the variability associated with the analytical technique. The identified stream stability analysis process for Castle Rock also provided some broad generalizations regarding computed stable slopes and offers some guidance for engineers and planners when budget or time do not permit a more exhaustive stream stability analysis. These broad recommendations establish a more site-specific recommendation than the prevailing 0.4% long-term stable channel slope often applied to studies along Colorado Front Range streams. The general findings based on the application of the new process include stable channel slopes that vary along the length of the reach of interest based on physical and hydraulic properties. These findings allow the optimized placement of stabilization structures and an opportunity for a phased approach to stabilization along the steep terrain unique to the area to help manage the uncertainty of assumptions inherent in the analytical technique.

One of the best ways to learn is through experience. This concept was one of the primary objectives of the Lost Creek restoration project at Rose-Hulman Institute of Technology (RHIT): to educate the campus and community on both the importance of healthy streams and the process of stream restoration. A restoration design for a section of Lost Creek running through the RHIT campus was developed as part of a graduate student investigative design project. The objectives of the restoration were to reconnect the creek with its floodplain, reduce bank erosion, and restore valuable stream habitat. In addition to the restoration design, the project consisted of several unique educational components that were designed to serve two primary purposes: demonstration and research/monitoring. This paper discusses the educational components used and the integration of stream restoration into undergraduate coursework. The research and monitoring components of the Lost Creek project were developed in conjunction with the current course offerings at RHIT. Monitoring is a vital component of any restoration project. For the Lost Creek project, it was possible to incorporate the monitoring plan into several of the institute's courses (e.g., AB320 — Ecology, CE598 — Stream Restoration, CE461 — Environmental Engineering Laboratory). Undergraduate laboratory assignments were developed to address each monitoring procedure. These laboratory assignments were then integrated into each participating course in order to evaluate restoration project status, identify problems and recommend maintenance activities, and provide recommendations to improve future projects. Overall, the results of this project provide Rose-Hulman with a unique educational opportunity to integrate on-campus sites as living laboratories where students can literally get their feet wet.

The rapid evolution of river restoration technology, in combination with the diversity of disciplines represented in the restoration field, has created ideal conditions for increased market demands for restoration short courses. Therefore, it is not surprising that there exist numerous short courses and certificate programs in stream restoration offered by private consulting firms, government agencies, nonprofit organizations and universities. These courses typically range from one day to week-long classes that introduce the student to basic concepts and principles of fluvial geomorphology and stream restoration. With an abundance of course offerings, it is problematic to determine what is being taught, who is teaching, to whom it is being delivered, and what is really being learned. There is growing concern that many short courses are offered as stand-alone entities, with no prerequisites and no assessment of learning. This can lead disconcertingly to over-confident, over-eager restorationists who do not fully appreciate the complexity and interdisciplinary nature of river restoration projects. In order to address these issues and meet an ever-growing need for restoration professional development, a stream restoration educational materials task committee (TC) of the River Restoration Committee of the ASCE-EWRI Hydraulics and Waterways Council was formed in May 2009. The goals of the TC are to provide the restoration community with (1) a recommended standard curriculum based on needs (technicians, engineers, planners, ecologists, biologists, etc.), (2) a list of educator traits most properly suited to cover that curriculum (not specific individuals or institutions), and (3) logistics of where and how to most effectively disseminate information. The objective of this paper is to present preliminary results from work completed by the TC, including a list of courses and outcomes (and level of cognition) that account for the insights of practicing engineers, needs of graduate programs, and pedagogical and personnel limitations of a specific program.

Penn State University (York and Harrisburg campuses) has been evaluating the effectiveness of state-funded stream restoration activities. Research has been performed on two branches of Codorus Creek, located in south-central Pennsylvania. This current research presents only the data obtained at Penn State Harrisburg. We examine the current pollutant loadings of two branches of this stream in conjunction with land use practices. Macroinvertebrates and periphyton are sampled routinely. Streamwater sampling for water chemistry analyses occurs during both baseflow and storm event conditions. Restored sites are compared to both impaired and control sites to determine whether restoration has any significant reduction in a pollutant's load. All sources contributing to the total nitrogen load to Codorus Creek have not been identified. Although restoration activities may decrease pollutant loads, such as suspended solids, restoration is not believed to be effective in decreasing nitrogen loads. Nitrogen is found more readily in the aqueous phase (streamwater) rather than adsorbed to sediment particles. Therefore, more effective ways to remove nitrogen in water is to decrease or eliminate the source or to treat the streamwater directly. Further monitoring and comparison of restored sites to control and impaired sites are needed. In addition, future work on the toxicity of the legacy sediments has been proposed.

Urbanization impacts watershed hydrology resulting in hydromodification of in-stream hydraulics and rapid adjustment of channel morphology thereby disturbing natural geomorphic and ecological processes in stream systems. Pool-riffle structure, capable of supporting diverse biological ecosystems, is frequently degraded in urban streams because of channel incision and the loss of channel-scale helical flow patterns, which are responsible for initiating and maintaining pool-riffle sequences. The objective of the current study was to restore pool-riffle bedform and channel hydraulics to maintain pool-riffle structure in an incised, straightened 270 m reach of Beaver Creek (Knox County, Tennessee). Property boundaries laterally constrained the existing channel thereby limiting extensive planform alterations (i.e., macro-sinuosity) in the restoration design. ArcGIS® and River2D®, a two dimensional depth averaged finite element hydrodynamic model, were used to design bed, bank and in-stream features to support maintenance of velocity acceleration/deceleration sequencing, energy dissipation and complex flow patterns, and bed and bank stability. Design included spacing pool-riffle sequences by integrating into existing channel constrictions and expansions. Also at each riffle and run location, bank material (1–2 m by 10–20 m) was removed to dissipate energy and create hydraulic macro-eddies; and gravel substrate was specified for augmentation at riffles. Flow patterns at multiple flow conditions (from baseflow to bankfull) for both the current condition and the design channel were characterized, and aquatic habitat was evaluated in River2D® generating weightable usable area for various fish species. The design channel was manipulated in ArcGIS® and evaluated in River2D® to develop a sustainable design by altering bed and channel form to create self-regulating pool-riffle sequences, rather than relying solely on natural channel design structures. Boundary shear stresses were calculated from model output to size substrate, design stable in-stream features to augment flow structure, and evaluate bank and bed stability. This work illustrates the utility of computational fluid dynamic models for stream restoration in urban watersheds where channels are in disequilibrium and a reference reach is not relevant. Model development and a description of design will be presented, with a design focus on rehabilitating degraded stream habitat.

The City of Urbana, IL intends to recapture an urban amenity by transforming Boneyard Creek, which runs through its downtown. Like many Midwestern streams, Boneyard Creek was channelized in the early 20th Century, and downtown Urbana was developed largely with its back to the creek, which was viewed as a drain of questionable value. Recently community groups have encouraged the City to use restoration of the creek as a focal point for a downtown revitalization effort, and in 2007 the City of Urbana chose the team of Wenk Associates and HNTB to develop and implement a master plan for that purpose. Within downtown Urbana Boneyard Creek consists of 2500 feet of inset open channel, the upstream half consisting of a 21-foot wide flat concrete floor and 8-foot high vertical sheet pile walls. Downstream of this the channel bottom is "natural" and the banks are reinforced by rock-filled gabion structures. Although the creek sits within a 50-foot wide drainage easement, adjacent properties are fully developed and numerous utilities run along and across the creek alignment. In March 2008, Wenk and HNTB completed the Boneyard Creek Master Plan. This plan would replace two stretches of the existing sheet pile walls and concrete bottom with a new cross-section consisting of a concentrated low-flow channel (width of 5–10 feet) and banks rising at 5:1 to 3:1 slopes up to meet existing grades. Similarly, a portion of the existing gabion-reinforced channel reach would be replaced with a low-flow channel and laid-back banks. The "natural conditions" vegetated channel banks would be managed to support native prairie grasses and other herbaceous vegetation (with only occasional trees and shrubs), to maintain adequate conveyance during high flow events. The improvements to the creek would be designed in coordination with the development of public spaces within the creek corridor and the establishment of a network of pedestrian and bicycle connections.

Channel width adjustment due to stream bank erosion is a common mode of channel form adjustment as streams respond to changes in runoff and sediment supply from the surrounding landscape. This is particularly observed in the highly disturbed watersheds of Northeastern Mississippi. Research is being conducted in the Town Creek watershed, MS to better understand how streambank erosion is affected by the position and characteristics of the eroding streambank in the watershed. Measurements of streambank profile adjustment using erosion pins and topographic surveys, flow velocity, and streambank soil erodibility using a jet test device was conducted at three different locations within the watershed. Soil chemical and physical properties were determined to evaluate effects on streambank soil erodibility. Erosion pins were monitored over a one year period. Topographic surveying has been performed on headwater unstable channels with actively eroding streambanks for six months. Streambank erosion and deposition processes were observed simultaneously at erosion pin locations. Erosion depths ranged from 1 mm to 560 mm, whereas sediment deposition depths varied between 1 and 360 mm. Preliminary survey results indicate erosion varying between 3 and 600 mm due to mass wasting and basal clean-out during and after storm runoff events. Soil streambank critical shear stress (τ_c) and detachment rate coefficient (k_d) determined by jet testing indicate a wide range of erodibility throughout the test locations.

Reclamation activities on coal mining sites to prevent excessive erosion have traditionally been very successful with the establishment of grass covers, on sites where the slopes are moderate to low. Establishment of native forest cover on reclaimed sites has become a priority directive of the US Department of Interior, Office of Surface Mining. However, standard construction techniques are based on slope stability criteria using high levels of compaction, resulting in poor soil medium for tree survival. A team of researchers at the University of Tennessee are engaged in studies with the overall objective to develop design criteria for stable steep slopes (~28–35%), minimal erosion, and successful reforestation. A part of the overall project, the focus of this presentation provides a summary of the hydrological and erosion monitoring results at three experimental study sites on active coal mining locations in East Tennessee. Each site was equipped with a fully automated weather station, and consisted of four measurement plots. Sediment yields were measured using Pinson divider budgets following an H-flume and sedimentation tank. Initial results characterized pre-cover conditions in which erosion ranged from approximately < 1 ton to 10+ ton per event. Particle size distributions of the transported sediment from the hillslopes were also characterized. Results from this study will guide erosion control and detention pond design practices at early stages of coal mining reclamation, prior to reestablishment of native forest cover.

The sediment transport and biological processes governing the fate and transport of the surface fine grained laminae (SFGL) has not been included in models seeking answers at the watershed scale. In this model development, the flow is used to drive the sediment transport continuity model which includes subroutines for fluvial erosion based on excess shear stress for cohesive sediment sources, i.e., SFGL, bed and bank, transport based on the residual transport capacity concept coupled with traditional deposition and sediment routing, and SFGL fate including biofilm generation and bioturbation of consolidated bed sediments. The model is applied to a lowland watershed in a conceptual watershed modeling framework. The model is calibrated for a stream reach in the watershed using concentration and flow data at the watershed outlet and from the tributaries that are used to calculate sediment flux using Einstein's approach. In addition, the critical shear stress, erodibility coefficient, and biological terms are parameterized based on literature reported values. The importance of small and moderate flow events to downcutting of the streambed and large events for deposition to the bed is found for the stream. Biological activity and bioturbation in the SFGL continue over time to develop eroded bed material. In this manner, biological rates can be seen as important for assessing geomorphologic rates on long time-scales.

Bed scouring at stilling basins downstream of gated spillways has been identified as posing a serious risk to the spillway's structural stability. Although this type of scour has been studied in the past, it continues to represent a real threat to water control structures and requires additional attention. A 1/30 scale Froudian model of one such structure operated by the South Florida Water Management District was constructed at Michigan Tech to further study this problem. A series of experiments were performed in this model to identify the conditions that induce maximum scour. Utilizing these flow conditions as baseline on subsequent experiments aimed at studying scour-reducing measures will verify these measures has the desired effect. The four flow conditions considered in the study were: controlled submerged, uncontrolled submerged, controlled free, and uncontrolled free. Gates restricting flow were positioned at the spillway crest and at the end of the flume where the model was built to control the tailwater level. Positioned downstream of the stilling basin was a scour chamber filled with uniformly graded sand representing the channel bed. The "distance check" feature of an Acoustic Doppler Velocimeter was utilized during the experiments to determine when scour equilibrium was established for a particular case. Point gauges mounted on a carriage above the experimental flume were used to measure the water surface profile at equilibrium. After the scour hole reached equilibrium, the flume was drained and the channel bed contour profile was measured. Key parameters considered during this study include flow rate, headwater, tailwater, water surface profile, bed profile, and spillway gate opening. These experiments show that the worst flow condition for scour was uncontrolled free flow with high headwater and low tailwater below the spillway crest. Results of these experiments are useful for predicting the effect of various flow scenarios on maximum scour near and away from the structure along with total scour volume.

Small-to-medium sized reservoirs are critical to providing water storage capacity for water supply agencies. These reservoirs provide many services, including irrigation, drinking water and other municipal uses, hydropower, environmental enhancements, recreation, and flood control. A reservoir is constructed knowing that, sooner or later, it will fill with sediment and no longer fulfill its intended uses. Since the 1990's, the state of Utah has experienced an overall net loss of total reservoir storage capacity due to sedimentation and the lack of new reservoir projects. In an effort to preserve the storage capacity of these reservoirs, the Utah Division of Water Resources (UDWRe) is preparing a study to quantify the problem, increase awareness of dam owners, and provide them with solutions to extend the useful life of their reservoirs. The report will be available for free download after March 15, 2010 at www.water.utah.gov. Part of the study includes a 5-step system for evaluating and mitigating sedimentation. This will allow individual reservoir owners to assess their situations and provide feasible alternatives for extending the life of their reservoirs. UDWRe hopes that this study will apply to owners of small-to-medium sized reservoirs throughout the United States, and perhaps even other countries.

Proper estimation of sediment concentrations in open channel flows is of critical significance to establish a viable water resources management plan. When modeling suspended sediment, sediment concentrations can be estimated from either the Advection-Diffusion equation or the empirical relationship with flow discharge. Although these methods provide fairly reasonable estimates of concentrations, there have recently been several accounts that point to the probabilistic properties of sediment particle movement in open channel flows. This paper attempts to develop a stochastic approach for quantifying the sediment concentration in open channel flow. The effect of probabilistic flow characteristics on sediment concentrations will be evaluated and discussed. The probabilistic characteristics of flows include random occurrences of large flow perturbations as well as turbulence. We take the Lagrangian approach to examine the uncertainty associated with random properties of sediment movement. In particular, we include the stochastic flow velocity into governing equations of sediment transport. The proposed method will be verified against experimental data. The proposed approach is expected to characterize the probabilistic property of sediment concentrations in open channel flow.

Aggregation and breakup processes play a major role in defining the settling velocity and transport properties of fine, muddy sediment. The inclusion of flocculation effects on the distribution of fine particles is, therefore, important in the interpretation and prediction of sediment and pollutant transport in harbors and estuaries. This study experimentally measures floc size populations as a function of time, turbulent shear rate and salinity using Houston Ship Channel sediments that have clay-silt-sand percentages of 50%-50%-0%. Quantification of the floc size population was accomplished using a non-intrusive floc camera capable of capturing particles in the range of 5–2000 microns and image processing. Turbulent shear rate and salinity were both found to play a significant role in governing floc size and the time to a constant particle size distribution. Observational results are presented according to the clay and silt contribution in aggregation that describe the effect of flocculation on the time dependent median floc size.

In order to fully describe the erosion, deposition and transport processes of sediments, it is necessary to understand the behavior of the suspended sediment profile and how it changes in response to changing external forcings. To this end, an approximate nonequilibrium suspended sediment profile for fully developed, quasi-steady flow has recently been developed and published by the author. This profile was developed analytically, on the form of the Rouse equilibrium profile, with several physical assumptions imposed on the development. In this paper, the original profile development is revisited. The profile is shown to be generally valid for unsteady flow, making it more generally applicable than the original development implied. Also, a more general form of the profile which includes concentration dependent settling velocity is derived, making it suitable for use in approximating observed mud profiles. The proposed profile is compared against numerical solutions to asses its validity.

The Three Gorges Project, located on the Yangtze River outside of Yichang, China, brings to the forefront of the world stage awareness of the environmental effects of creating a dam and reservoir system. It is especially relevant today with the talk of exploiting renewable energy sources such as hydropower dams. This paper discusses the experiences of an undergraduate civil engineering major who visited the project in order to better understand those impacts. The paper first looks at the negative environmental impacts such as increased sedimentation and nutrients in the reservoir and increased erosion downstream. Large dams have been known to decrease the upstream water quality by introducing an increase in nutrients from agricultural runoff. They also block sediment which can collect on the upstream face of a dam. This causes the water downstream to have a reduced sediment load resulting in increased erosion. Also, peak water discharge is decreased which is detrimental to flood plains that require a flood to renew their nutrients. Regarding benefits, this work will quantify the reduction in coal use and its contribution to greenhouse gasses. Also discussed is the increased shipping capacity afforded by the dam construction - a 280% increase. This substantial cargo capacity not only provides economic efficiencies, but it also reduces carbon emissions when compared to terrestrial transportation. Lastly, the downstream flood control benefits, which are projected to reduce the ten-year flood to a hundred year flood event, will be discussed.

Due to high growth rate of large cities, in reconstruction and rehabilitation of urban water infrastructures, new demands of the system should be considered. Different possible scenarios are defined to deal with these increasing demands and are tested to find the appropriate one with the least risk. In evaluating risk of these scenarios application, the performance of system under their application is considered. The system performance is quantified in its planned period of operation. In this study a small water distribution network is considered as the case study. Different rehabilitation and reconstruction practices are defined for this system and system performance under these scenarios is evaluated. Then the acceptable risk of water supply with adequate quantity, quality and pressure based on the water demand type is determined and the scenarios are compared with the defined thresholds. The scenarios that pass this step are considered for cost-benefit evaluation to find the optimal solution. The system performance under application of selected scenario is evaluated in its operation period. This will help to find the most practical solutions in infrastructures improvement and avoid from starting projects with high risks that are common especially in developing countries and usually are left incomplete.

Most of Yemen is located in an arid climate with convective storms that produce flash floods and cause significant damage. A Tropical Storm landed in the eastern part of Yemen between October 23 and 25 of 2008 causing severe destruction and leaving thousands without their homes or livelihoods. A probabilistic risk assessment project, funded by the World Bank, Global Facility for Disaster Reduction and Reconstruction (GFDDR), was conducted for Hadramout and Al-Mahra governorates to (1) determine the extent and depth of flood risks in these governorates and (2) develop recommendations for the recovery and reconstruction of these areas to reduce devastation from future flood events. As a result of this Tropical Storm, the Government declared Hadramout and Al-Mahra governorates as disaster areas. Nearly 6,600 homes and huts in these two governorates sustained total or significant damage, leaving 25,000 people in need of shelter. Flooding was reported to have claimed 73 lives, left 17 people missing, and injured many others. The flooding not only damaged homes but also had a devastating effect on agricultural land. It is believed that nearly 50 percent of the population of the affected areas had their livelihoods destroyed or substantially damaged. A flood hazard analysis was performed to recreate the Tropical Storm of 2008 and to determine the extent and depth of flooding for the 100-year flood frequency event. Hydrologic modeling analysis performed with HEC-HMS software was used to process precipitation data, identify basin characteristics, and simulate the design flows produced by the Hadramout and Al-Mahra river basins. Hydraulic modeling performed with HEC-RAS software used the design flows and geometry data to model the stream conveyance. HEC-GeoHMS and HEC-GeoRAS were used in the pre- and post-processing efforts to expedite the parameter inputs and mapping process. Many challenges were addressed during the modeling processes. Specifically, there was limited historical data that could be used in the flood model developments. In addition, a high resolution digital elevation model (DEM) was not available for use in the hydrologic and hydraulic model. Finally, only a limited number of high water levels and flood extents were obtained after Tropical Storm 03B to be used in the calibration process. These challenges were overcome and floodplain maps were developed along the major waterways of the Hadramout and Al-Mahra governorates. These maps are being used to determine the areas prone to flooding and will be used to make recommendations in the rebuilding of roads, buildings in populated areas, agricultural lands, and flood control structures.

In terms of per-capita availability of renewable water resources, Jordan is one of the most water-scarce countries in the world. Amman, the capital of Jordan, has grown rapidly in the past 50 years, and its internal water resources can no longer meet the needs of its burgeoning population. Per capita water use in Amman is much less than that of its American or European counterparts, with further efforts in water conservation and demand management necessary for the long-term sustainability of the system. Major water works have come online in the past decade, and with rapid population growth and economic development, other, larger-still water works are under way. In the past 5 years alone, the water supply situation has changed so rapidly for Amman as to make the data of 2004 essentially obsolete. This report presents the current state of the water resources system in the Greater Amman Area (GAA) with an emphasis on the purview of Miyahuna, the Jordan Water Company.

Living Waters for the World (LWW) is a global mission resource of the Synod of Living Waters, a governing body of the Presbyterian Church (USA). LWW trains, equips, supports and links mission teams to share clean water with needy communities with over 320 clean water systems in 24 countries around the world. LWW serves communities that have available but contaminated water and has developed modular clean water systems (CWS) to address the needs of each community. LWW projects contribute to the UN Millennium Development Goal "Halve, by 2015, the proportion of the population without sustainable access to safe drinking water..." LWW CWS utilize standard treatment technologies: filtration, micro-filtration, and disinfection and can process up to 1100 liters (290) gallons per hour. LWW has found that multiple batches each day will support the critical water needs of up to 2000 people. The Standard CWS receives raw water from either ground or surface water. Raw water passes through a 50 micron sediment filter and is pumped through a 5 micron then a 0.5 micron micro-filter. This water is disinfected with Ultra-violet (UV) light or by ozone injection. The Standard System hardware and equipment costs are about $3,000. Operating costs can be as low as $0.005 per gallon based on local electricity rates and other factors, not including labor. The Clean Water Systems Handbook is LWW's comprehensive training manual. Block Flow Diagrams and Decision Trees help partners determine the best CWS for their needs. The most complex system includes activated-carbon filtration, water softening, and reverse osmosis. Clean Water U is LWW's five-day, hands-on training program. Each of the three separate courses emphasizes the "train-the-trainer" approach in an experiential training environment. These courses include: CWU 101: Team Leadership, Partnership Development, Field Survey and Water Testing, CWU 102: Health and Hygiene Education, and CWU 103: Water System Installation, Operation and Maintenance. Covenants between an Initiating Partner and the Operating Partner establish a three-year commitment to make four trips to the site of the Operating Partner. The first is for site survey and partnership development activity where Partners negotiate the covenant that covers all equipment issues, costs, and who will be responsible. Operating partners can operate their system as a micro-business, selling water for up to 50% of the commercial rate for bottled water. However, water must always be provided for those unable to pay. The second trip is the education and installation trip where the system is installed and the community is trained in health and hygiene education. The third and fourth trips are annual follow-up visits to monitor the progress of the project. When a covenant expires, the partners can renew it, become embedded in a network or operate independently. Regional Networks help make these CWS more sustainable. LWW has eight Networks established in the Yucatan (Mexico), Guatemala, Haiti, El Salvador, Honduras, Nicaragua, Dominican Republic, and in Appalachia in the US. Each network is organized by a US volunteer-based Coordinating Team with some paid support staff in some countries.

Since global commitment to the Millennium Development Goals (MDGs), there have been major gains in reducing the percentage of the world's population without access to improved water supplies. However, as more people gain access, the difficulty of expanding access to the remaining population increases as the easier solutions are completed, and areas of greater water stress remain. In the Pacific island nation of Samoa, access stands at approximately 90%, but the remaining 10% of the population resides in areas of limited surface or ground water resources. Many of these communities have turned to rainwater harvesting as a supply source. The village of Falelima, Samoa on the island of Savai'i is one such example. Residents meet their water needs through rainwater harvesting, but the ability to collect and store rainfall varies greatly between individual families. This paper examines the rainfall collection areas and storage volumes needed to provide various service levels throughout the year. A simple model is used to produce reliability design curves for the village that can allow users or outside agencies to determine how the addition of system capacity will increase water availability to a certain proportion of families. Finally, outcomes from a recent construction project are evaluated, and recommendations are made for further work to provide all families with a minimum level of service

The provision of safe drinking water is a pressing need in Africa, Asia, and Central America. The UN recently estimated that 1.1 billion people lack access to improved water supplies. The failure to address this need is an injustice that has strengthened the grip of poverty, resulting in suffering and death every day. "We shall not defeat AIDS, tuberculosis, malaria, or any other infectious diseases that plague the developing world until we have also won the battle for safe drinking water, sanitation, and basic health care." (Kofi Annan, 2008) A part of the failure is inadequate application of technology. A number of water treatment methods are time-tested and well-documented in their effectiveness, but the question remains, can these proven technologies be packaged to meet the needs of the poor in the developing world? It is common to think of village water needs when discussing the drinking water needs of the developing world, and those are many, but safe drinking water for the urban poor is a major and growing challenge. "The locus of global poverty is moving to cities, a process now recognized as the urbanization of poverty. Without concentrated action on the part of the municipal authorities, national governments, civil society actors and the international community, the number of slum-dwellers is likely to increase in most developing countries." (Kofi Annan, 2003) What are the particular drinking water needs of the urban poor in the developing world? What are their options for safe drinking water? This paper attempts to answer these questions by a focus on the poor of Kampala, Uganda, because of the author's experience living in this city and conducting field trials in that location. The author, on leave from CH2M HILL, volunteered for 10 months to assist with designing and implementing water improvements in East Africa through the non-profit organization, Engineering Ministries International. The author conducted informal field trials of a new household water treatment invention with Kampala residents during this period. The following topics are covered: 1 Safe drinking water challenges faced by the urban poor 2 Commonly used household treatment methods and their costs 3 Application of a new invention—description, acceptance, effectiveness, and cost 4 Future directions for meeting the water needs of the urban poor in the developing world The particular water treatment invention that is the subject of this paper may become one of the products to fill the technology gap for the urban poor. The patented product is currently without a name and is referred to as UV007 in this paper. It is a reliable and robust product, one that appears to be cost-effective compared to alternative methods. It is designed for household or kiosk-level use. It uses ultraviolet light in the germicidal wavelength to disinfect water on a batch basis. The unit is human-powered, by a hand-crank or by a bicycle, making it attractive for the significant percentage of people without electricity. It has been shown in laboratory tests to achieve EPA standards for inactivation of MS-2 coliphage. Informal field trials using second-generation prototypes were conducted in Kampala during 2009 and 2010. The feedback from the participants will guide the development of this product. Assembly can be implemented in-country providing economic benefits as well as safe drinking water. It can be paired with micro-credit programs to yield jobs in the very developing world applications where UV007 will be used. The unit is especially applicable in urban settings, such as Kampala, where the municipal system provides water low in particulates but delivery obstacles render distributed water unsafe. It is appropriate and necessary to provide point-of-use treatment and indeed, most Ugandans residing in Kampala perceive this need. Collaborators to date include Chris Smith, President of Intellegration LLC (Richland, WA), Professor Jeff Nason, Chemical & Environmental Engineering Department, Oregon State University, and John Coombe (formerly) and Stephen Hall of the Western TechSet program through the University of Denver.

This dissertation presents the development of Integrated Water Resources Management (IWRM) in Ghana. It presents realistic experiences of the opportunities and constraints to the implementation of IWRM. The institutional management of water is offered including analysis of related policies, the governmental structure, and the national framework for the management of water resources. Though Ghana is well gifted with significant freshwater resources, the challenges of speedy population growth, increased urbanization and industrialization, uncontrolled environmental degradation and pollution are principal to accelerated depletion and degradation of the available water resources. To meet the above challenges, the government of Ghana (GOG) must institute reforms in the water sector to ensure that water services are provided and managed with increased efficiency and cost effectiveness. These reforms and the changes towards IWRM are discussed in the paper. Limitations and opportunities are identified. The paper presents an idea for the future towards truly Integrated Water Resources Management. This includes the Sector Wide Approach to Planning; the idea for management at catchment or basin scale; cross-sectoral activities to develop confidence, increased information dissemination; and the approval of management tools and modeling techniques in IWRM.

As part of a set of immediate and long-term actions taken in the drought of 1994–2003, on July 3^rd2003, the Mexican and the U.S. sections of the International Boundary and Water Commission (IBWC) signed Minute 309; an amendment to the treaty of 1944 that specifies a set of water conservations measures implemented in the Rio Conchos basin and the conveyance of saved water to the main stream of the Rio Grande/Bravo on December and January. These water conservation measures include the reduction of conveyance losses and the increase in application efficiency on the farms in the basin, therefore, a substantial fraction of these savings are in the form of reductions in groundwater recharge, and not in the reduction of physical losses of the system. In this paper, we evaluate performance of the policy proposed in Minute 309 for aquifers, reservoirs, water users and the environment. This evaluation is done in a basin model constructed in the Water Evaluation and Planning system (WEAP) software. Additionally, a scenario where the water savings are delivered in environmental patterns is also presented. The description and evaluation of Minute 309 are presented along with a comparison against the current water management policies and the environmental pattern water savings delivery scenario.

Over the last three years, hundreds of investigators from U.S. and Canadian government and non-government agencies and universities around the Great Lakes have been studying the possible factors responsible for recent declining upper Great Lakes levels. They have concluded that over the last four decades, the conveyance of the St. Clair River, the river connecting Lake Michigan-Huron to Lake Erie, has changed due to man-made factors like dredging but also due to natural factors like a major ice jam that occurred in 1984. However, they also determined that the declining lake levels were due primarily to climatic variability and glacial isostatic rebound. As such, remedial structural measures in the St. Clair River were not warranted. With that important phase of investigations ending, the International Upper Great Lakes Study (IUGLS) is shifting its focus to investigations toward formulating alternative plans for Lake Superior outflow regulation with the goal of providing benefits to existing and emerging interests. The Lake Superior Regulation Task Team has organized a team of performance indicator, integration and advisory technical work groups to formulate and evaluate alternatives to the present plan for Lake Superior regulation, Plan 1977-A, which has been in use since 1990. It already has been determined that improvements based on historic supplies will be small. However, considering more extreme conditions that could result under climate change-type scenarios, improvements may be identified, particularly when considering adaptive management. Connecting channel structural changes will also be considered. This paper describes the studies that are planned and the strategies that are being envisioned that will lead to alternative regulation plans by Study completion in the Spring of 2012.

Under the challenges of present and future population increase, urbanization, and global climate change, hydraulic analysis and design for water supply, drainage, and irrigation conveyance system are becoming increasingly important in order to solve the water management problem. Determination of critical and normal depths for irrigation and drainage channels is a classic but also important task for efficient hydraulic design, therefore, a significant number of researches have been done in this area. Unfortunately, there is no analytical solution to explicitly and directly compute critical and normal depths for most of channel cross-sections except for critical depth in rectangular and parabolic sections and critical and normal depths in triangular section. Designers may use a manual trial-and-error method, which is time-consuming and troublesome, or a chart method, which uses log-scale charts and has low accuracy in the solution. Various approximation equations have been developed for common open-channel sections with various degrees of estimation errors and limited application conditions. There are very limited researches for rounded-bottom or - corner sections. There are many hydraulic or drainage or stormwater computer programs (software packages) available that compute and report critical and normal depths for common cross-sections but there is very little information on what approximation equations or numerical methods are used (black-box approach to users). This study includes a comprehensive review and evaluation of different methods determining critical and normal depths for eight types of open-channel sections: circular, rectangular, trapezoidal, triangular, rounded-corner rectangular, rounded-corner trapezoidal, rounded-bottom triangular, and U- shaped. It also presents easy and efficient method to calculate critical and normal depths for these cross-sections using Solver function in Excel. General equations for geometric elements for these cross-sections are developed and used to create Excel worksheets determining critical and normal depths. Using the spreadsheet with Solver function designers not only get in-depth understanding on basic sectional geometry but also do not have to depend on commercial computer programs for computing basic hydraulic design parameters. We present a VBA code for repeated applications of Solver function that is useful for solving various problems in irrigation and drainage engineering. The method developing geometric equations for different depth ranges can be applied to more complex compound channel sections; and as long as we can develop equations computing geometric elements, then Solver can be used to determine critical and normal depths for the complex compound sections.

Determining discharge in a stream is important to the design of culverts, bridges, and other structures pertaining to transportation systems. Currently in Utah regression equations exist to estimate recurrence flood year discharges for rural watersheds greater than 30 mi², and the rational method is used for areas smaller than 0.5 mi², however, there are not good methods available to estimate discharges for watersheds that fall between the two approaches. To solve this issue, a flood frequency analysis was conducted on small rural watersheds within the southwest portion of the state of Utah to develop regression equations estimating flood flows for mid-size watersheds. The watersheds selected range from 0.5 mi² to 30 mi², and have at least 10 years of peak discharges recorded by the USGS. A flood frequency analysis was performed on the peak discharges for each USGS stream gage according to Bulletin 17B guidelines, using the PeakFQ program. Flood flows were regressed against multiple parameters (watershed geometries, soil characteristics, precipitation data, land use data, etc.) to estimate different recurrence flood years (i.e. 2-, 5-, 10-, 25-, 50-, 100-, 200-, 500-year). Regression equations were developed in the format of the rational method (Q = CiA), where the runoff coefficient was regressed against appropriate determined predictor variables, including parameters such as basin slope, basin length, basin average elevation, percent of basin flowing south, composite curve number, saturated hydraulic conductivity, and mean annual precipitation.

Soil erosion in irrigation furrows significantly impacts the efficiency of irrigation, infiltration and fertilization. This study developed a numerical model to simulate unsteady flow and the resultant soil erosion and sediment transport in irrigation furrows. The model solves a revised version of the one-dimensional Saint-Venant equations by considering the loss of mass and momentum due to infiltration and sediment transport. The modified Laursen sediment transport formula of Strelkoff and Clemmens (2005) applicable to the transport capacity of silt and clay sized fine sediment was adopted. Furrow infiltration was calculated by the Kostiakov infiltration equation in which the empirical parameters were calibrated by using field observed data. The developed model was tested with a field case, and the results reasonably agreed with the field measurements. The same experimental case was also simulated with the WinSRFR model and compared with the current model.

Assessing the project efficiency of irrigation systems and water use efficiency of crops over large irrigated areas requires daily or seasonal evapotranspiration (ET) maps. Mapping ET or latent heat flux (LE) can be achieved spatially for land surfaces using remote sensing inputs such as surface reflectance and radiometric surface temperature (T_s). The energy balance (EB) equation requires net radiation (R_n), soil heat flux (G), and sensible heat flux (H) to derive LE as a residual. Although R_n and G can be estimated with acceptable accuracy, H may be under estimated when T_s is used rather than the surface aerodynamic temperature (T_o) in the aerodynamic resistance equation. The value of T_o cannot be measured directly because it varies with atmospheric forcing resulting from radiation, wind speed and air temperature, and with variable surface conditions. In this study, T_o for dryland cotton in the Texas High Plains and irrigated alfalfa in Colorado was determined using T_s, air temperature, leaf area index, and surface aerodynamic resistance, and ET measurements obtained with large weighing lysimeters. The specific performance of the modeled T_o for cotton and alfalfa was assessed using an aerodynamic profile method. Results indicated that the T_o model based on aerodynamic resistance better agreed (0.2±1°C) with measured T_o values using the aerodynamic profile method.

Considering the increasing pressure on natural resources to augment production for satisfying grain demand for the growing human and livestock population, ground water supply in the Texas Panhandle reflects itself as a limiting yet indispensable factor. This study evaluates the effectiveness of eight potential water management strategies in terms of water savings that could be used to meet irrigation shortages of six irrigation deficit counties in Region A of Texas Panhandle, namely Dallam, Hansford, Hartley, Hutchinson, Moore and Sherman. These strategies include Irrigation scheduling, Changes in crop variety, Irrigation equipment efficiency improvements, Changes in crop types, Conservation tillage methods, Precipitation enhancement, Conversion of irrigated land to dry land and Biotechnology adoption respectively. Biotechnology adoption emerged as the most promising water management strategy, given the high associated cumulative water savings and reduction in annual water use for all the six counties of study, however a careful analysis of implementation of each of the strategies is required to incorporate them in to the agricultural production systems of the region.

Contamination of surface and ground water has become a major problem related to different agricultural and irrigation practices. Nitrate; one of the principal plant fertilizers, is the chemical having the greatest effect on such practices. Nitrates are highly soluble in water with low retention by soils. Best Management Practices have been developed to guide fertilizer use and minimize nitrogen losses, but they do not address control of nitrate movement from the crop root zone. Electro kinetics, an in-situ soil remediation technique, has shown to be an effective method for controlling nitrate movement and retaining it near the root zone for further removal. Laboratory studies found that the electro-kinetic process effectively concentrated and retained nitrate close to the anode in sandy soils using either horizontal or vertical soil columns. The effectiveness of the used technique depended on the initial nitrate concentration, the degree of saturation of the soil and the amount of applied electricity (current and duration). It was also shown that the effectiveness of the electro-kinetic process in retaining nitrate close to the anode is highly affected by the percentage of clay in soil. For the same amount of electricity, the loamy soils showed considerably slight migration of nitrate to the anode while the clay soil showed no migration of nitrate. This paper aims at reviewing the different electro kinetic techniques used to control the movement of nitrate in different soils, summarizing the important results and evaluating the effectiveness of such techniques with each type of soil.

To resolve problems like inadequate maintenance of water conveyance conduits (irrigation channels) and associated hydraulic structures, unauthorized usage of water, and inequitable distribution of water, the Irrigation and Power (I&P) Department of Punjab Government handed over the Lower Chenab Canal System (East Circle), having 119 distributaries with total canal command area of 1.85 million acres, to Farmers Organizations (FOs) as a pilot project. To study the effects of this irrigation management transfer (IMT) on the Lower Chenab Canal System, this study was designed. To investigate the IMT impacts, the daily head and tail discharge data from 2006 to 2009 were collected from the Project Monitoring and Implementation Unit (PMIU) of the Irrigation & Power Department. Based on this data the Delivery Performance Ratio (DPR), Capacity Factor (CF) and status of supply at tails of channels were determined. Besides that, assessment of impact of supplies at the tails after IMT was made. Relative DPRs for crop seasons of Kharif 2006, Rabi 2006—2007, Kharif 2007, Rabi 2007—2008 and Kharif 2008 were computed as of 0.72, 0.68, 0.87, 0.86 and 0.76 respectively. Results showed that there was an increase in supply at the channels tail during Kharif 2007 and Rabi 2007—2008. The analysis showed that the percentage of tails, in term of average number of channels, which remained dry during Kharif 2006, Kharif 2007, Kharif 2008 and Kharif 2009 season were 18%, 12%, 16% and 5.7% respectively; despite the fact that channels run as per authorized head discharge. The data of Abiana (water revenue) collection for different seasons were collected and impact of IMT on the Abiana collection and assessment was investigated. A general trend of decline in revenue collection was noticed. This study would be helpful for the understanding of the reforms process and to make the improvements in the management system. It would provide findings how to improve the method of Abiana assessment and collection and to enhance the equitable distribution of supply at the tails of the channels.

Metro Vancouver (MV) serves over two million people and comprises 22 member municipalities, one electoral area and one treaty First Nation. MV provides a variety of services to its members, including regional water supply treatment and transmission. The primary sources of water supply are the Capilano, Seymour and Coquitlam reservoirs. The Seymour and Capilano reservoirs supply up to 70% of MV's drinking water, with the Coquitlam Reservoir supplying the remainder. MV's regional supply system consists of 550 kilometres of water mains, 14 pump stations, and 20 peaking reservoirs. Three primary chlorination treatment stations, six pressure regulating sites and 113 metering stations are also included in the system. Historically, any one of the three sources could be removed from service under winter demands. This has sometimes been necessary to address periodic episodes of elevated turbidity resulting from winter storms. However, the system dynamics will change significantly with the commissioning of a new filtration plant located in the Seymour area. Water from both the Capilano and Seymour sources will be mixed and filtered at the Seymour Capilano Filtration Plant (SCFP) and transmitted to the system. The new SCFP will ensure that clean drinking water can continue to be provided via both the Capilano or Seymour headworks during a turbidity event in either of those reservoirs. This step change in system operation, however, will alter the hydraulic heads delivered by the Capilano and Seymour systems, hence posing a significant change in system dynamics. Due to the highly dynamic and complex nature of MV's regional water supply system, a hydraulic simulation model of the water system was developed using EPANET software to assist in system assessment. This paper outlines the challenges in using this model to develop both short-term operational strategies and long-term planning strategies. After presenting an overview of model development, calibration, verification and scenario simulation, two case studies will be discussed in this paper: (1) Investigating options for supplying a member municipality, the City of Richmond, with temporary alternative sources due to supply disruptions during construction of a major subway line which severed their primary feed; and (2) Reviewing options to defer a second supply intake at Coquitlam by maximizing supply from the Capilano and Seymour sources.

During the twentieth century, the levels of the Great Lakes have been modified by outflow management from Lakes Superior and Ontario. Recent studies have been undertaken to improve this management engaging stakeholders to help identify refinements to not only consider existing interests like commercial navigation and hydropower, but also interests new to the management process: recreational boating and ecosystems. The International Lake Ontario-St. Lawrence River Study which was completed in May 2006, proposed alternatives to the regulation plan for Lake Ontario, Plan 1958-D, which were developed using shared vision planning principles and techniques. The on-going International Upper Great Lakes Study, scheduled for completion in the Spring of 2012 that will identify alternatives to the present regulation plan for Lake Superior, Plan 1977-A, is also applying shared vision planning to arrive at alternatives. This paper describes the collaborative approaches used in these two case studies pointing out their similarities and differences which can serve as a guide for other large-scale studies and projects.

A new approach to identifying climate risks that would require adaptive management is being used on the Upper Great Lakes. The standard practice has been to simulate water related impacts expected under climate change by replacing current climate water supply with projected water supplies derived by downscaling the predicted changes in temperature and precipitation from General Circulation Models (GCMs) to transform the current hydrology. These simulations may provide a rough guess of what the future holds but are not particularly useful for decision making. Nor are they designed to be, although some decision is typically the endpoint of such efforts. For example, questions such as "when should we change our system" or "how much should we change" are difficult to address when no probability can be assigned to a particular climate change outcome used and there's no way to quantify the expected skill of GCM projections in the next century. The new approach presented here begins with stakeholders rather than climate models. Planners ask stakeholders and resource experts what water conditions they could cope with and which would require substantial policy or investment shifts. This is then formalized with a water resources systems model that relates changes in the physical climate conditions to performance metrics of interest to stakeholders. After these are established, hydrologists and climate scientists estimate the plausibility of the water conditions that exceed the coping thresholds, taking into account not only climate change but natural climate variability and stochastic variability observed with a stationary climate assumption. This paper reports on the early stages of a two year effort culminating in a Study Board recommendation to the International Joint Commission in the spring of 2012.

Two cities in Northern Colorado (Fort Collins and Greeley) have partnered with The Nature Conservancy and other organizations to test the use of Shared Vision Planning for the planning and permitting of water supply reservoirs. The cities propose to expand two existing reservoirs on the North Fork of the Cache la Poudre River, and have applied to the US Army Corps of Engineers for Clean Water Act Section 404 (CWA 404) permits. The CWA 404 permitting program has a legacy of controversy, especially for water supply projects in high growth areas. Shared Vision Planning has been proposed as a possible new path to providing needed water supply while minimizing environmental impacts and the controversy they cause. Much of the controversy around these permit decisions is focused on technical questions. The Corps, EPA, permit applicants, and environmental interest groups rarely agree on key technical questions such as growth projections, water use rates, water availability and ecological impacts of the projects. Collaborative modeling is key component of Shared Vision Planning and allows stakeholders in these controversial projects to jointly define how the technical analysis of a project will be done. Stakeholders collaborative use the resulting Shared Vision Models to develop and evaluate plausible alternative solutions. There are number of challenges in developing Shared Vision Models and best practices for this type of collaborative modeling are currently being standardized and documented by an American Society of Civil Engineers (ASCE) committee. And the nature of the Cache la Poudre Shared Vision Planning process brings its own challenges. Planners and modelers must to decide how to integrate SVMs with several legacy models, how to make use of available data for environmental impacts, how to integrate SVMs with data and models used for the EIS, all while addressing key technical issues in a transparent manner. This paper will recount the Shared Vision Modeling experience in the Poudre case, highlighting some of the challenges and lessons learned.

The case of the Laguna region offers an example of how the water planning process under conditions of unsustainable water use, gets involved with social, economic, political and historical complexities of stakeholders' conditions and priorities. Four main findings were identified as disturbers that threaten the sustainable possibilities for the region using a qualitative approach: lack of research on planning and management, communication dissonance among stakeholders, disagreement over problem identification and disagreement over solutions. Any new strategy for water planning must include an integrated research program that could identify priorities on research; it should consider needs, perspectives and participation of all water users; promote the development of a mechanism that helps identify the problems and develop a communication strategy that improves trust and effective feedback among stakeholders.

Growing populations and finite water supplies have led to the expansion of water supply projects in the West and Southeast. In many cases, cities will need a federal Clean Water Act permit to expand their water supplies. In the past, the permitting process for such projects has at times resulted in poor outcomes for either water suppliers or the environment. For example, in March 2009, a U.S. District Court judge ruled the Corps and EPA were "arbitrary and capricious" in their approval of a permit to build the King William Reservoir in Virginia. A month later, after two decades and over $50 million worth of planning, the project was suspended. Shared Vision Planning, a collaborative planning process with technical and social components, may offer a better approach. The cities of Fort Collins and Greeley Colorado have joined forces with the Nature Conservancy and other organizations in a limited experimental application of Shared Vision Planning in a water supply permitting process. This effort is being conducted separately from but in parallel to the permit assessment. The participating parties hope that good initial outcomes will lead to expanded collaboration. This paper describes how the parties explored the benefits and risks of collaboration, how they decided to conduct this experiment, and how they are using Shared Vision Planning to explore alternative ways to meet both water supply and environmental objectives, and what options they are considering next.

Cooperative game theory is a useful tool for determining if increased benefits exist for transboundary river basin stakeholders through cooperation in water resources management. Cooperative game theory has been used in many applications of water resources management including cost allocation from water development projects, cost allocation of regional wastewater treatment and transboundary water resources management. This research applies cooperative game theory to a water management in the transboundary Rio Grande/Bravo river basin located in North America. A cooperative game was created using a water management scenario which includes some of the largest irrigators in the United States and Mexico as players. This water management scenario is designed to improve water availability to the irrigators as well as considering environmental flows in the basin. Environmental flows account for the importance of flow variability to the health of an ecosystem and attempt to capture this flow variability as a range of flows which account for seasonable variability, magnitude, timing, frequency and the rate at which these flows change. Cooperative game theory is used to quantify the potential increase in benefit to the players and define a negotiation range for each player.

Shared Vision Planning (SVP) is a collaborative approach to water (resource) management that combines three practices: (1) traditional water resources planning; (2) structured participation of stakeholders; (3) (collaborative) computer modeling and simulation. The authors argue that there are ample opportunities for learning and innovation in SVP when we look at it as a form of Policy Analysis (PA) in a multi-actor context. SVP faces three classic PA dilemmas: (1) the role of experts and scientific knowledge in policymaking; (2) The design and management of participatory and interactive planning processes; and (3) the (ab)use of computer models and simulations in (multi actor) policymaking. In dealing with these dilemmas, SVP can benefit from looking at the richness of PA methodology, such as for stakeholder analysis and process management. And it can innovate by incorporating some of the rapid developments now taking place in the field of (serious) gaming and simulation (S&G) for policy analysis. In return, the principles, methods, and case studies of SVP can significantly enhance how we perform PA for multi-actor water (resource) management.

Six years ago, the Federal Emergency Management Agency (FEMA) embarked on an ambitious program known as Flood Map Modernization (Map Mod) to update the nation's flood hazard maps. Map Mod is a multi-year effort to transform FEMA's flood map inventory from a paper format into a digital format in order to provide communities across the nation with updated flood hazard maps and data, enhancing local decision-making — ranging from permitting, planning, development, and insurance to construction and disaster planning exercises. This paper will describe Map Mod goals and accomplishments as well as benefits to local, state, and regional entities. It will also describe the Risk Mapping, Assessment and Planning (Risk MAP) program that FEMA is now initiating and which builds upon the successes of Map Mod and the lessons learned from the program.

Research that characterizes and explains the influences of large-scale atmospheric circulation patterns on New England (NE) hydrology has been limited (Bradbury et al. 2002b; Kingston et al. 2006), despite widespread efforts to correlate these atmospheric patterns with local NE climate. Specifically, little research has investigated seasonally-lagged correlations. Such relationships are necessary to produce seasonal streamflow forecasts, a technique that can provide valuable information to water managers and planners throughout New England. This study investigates correlations between seasonal streamflow indices and three atmospheric circulation patterns: 1) El Niño/Southern Oscillation (ENSO), 2) the North Atlantic Oscillation (NAO), and 3) the Pacific North American (PNA). The streamflow indices considered are the annual seven day low flow (SDLF) and its date of occurrence (SDLFDate), the annual peak flow (PF) and its date of occurrence (PFDate), the annual center of volume (CV) and its date of occurrence (CVDate), the winter/spring center of volume (CVWS) and its date of occurrence (CVWSDate), winter-average (Dec. – March) streamflow, autumn-average(Oct. –Nov.) streamflow, spring-average streamflow (March – June), and summer-average streamflow (July – Sept.). Table 1 summarizes these indices and establishes the notation to be used throughout the rest of this study.

The purpose of this paper is to demonstrate the efficacy of using an optimization model to suggest reservoir rules that address emerging environmental concerns while maintaining historical operating objectives for management in the Connecticut River. This is demonstrated by exploring the use of a linear programming model that optimizes both a variety of objectives while constraining operations to conform to past operating rules. Previous studies incorporating environmental flows into multi-objective optimization models have been successfully conducted on other river basins. Kuby et al. found removal of twelve dams reconnected 52% of the Willamette River while only decreasing hydropower by 1.6%. Although dam removal is not considered in this study, the goal is the same: restoring more natural flows while maintaining previous objectives. The performance of this study's model was evaluated using storage risk analysis and comparison to historical operations. The Connecticut River is the largest river in New England and flows along the border of New Hampshire and Vermont and through western Massachusetts and Connecticut. The basin is home to 2.3 million people and numerous fresh water aquatic ecosystems, and many hydropower facilities. This study focuses on the West River and the Westfield River watersheds, two of the 44 sub-basins. Figure 1 presents the Connecticut River basin with the two sub-basins of interest in this study. Each basin has ecological targets including flows for diadromous fish, mussels, flood plains maintenance, and salmon stocking. The ecosystems of the river depend on natural variation of streamflow, especially seasonal high and low flows. Through the Connecticut, the river's many dams impact the basins' streamflow, reducing this variability. (Nedeau 2008).

Control of combined sewer overflows (CSOs) may be enhanced through real-time decision support. An optimization algorithm adapted for changing rainfall is used to dynamically control complex sewer hydraulics to minimize CSO volume. Different methods of enhancing the optimization for real-time processing consist of: separating the hydraulic model for multi-objective optimization or to optimize only critical portions of the sewer system, using an efficient optimization technique, and incorporating memory into the optimization to speed convergence to a solution for each forecasted rainfall change. Potential optimal management solutions and the associated environmental characteristics can be stored and used to re-initialize the optimization at each environmental change. The memory may also be altered to indicate what precision of hydraulic model should be used for different rainfall conditions.

Multipurpose reservoir operation often involves optimization of multiple conflicting objectives. In this paper, a Multi-objective Particle Swarm Optimization (MOPSO) is developed in which non-domination sorting and crowding distance approaches are used to find Pareto optimal solutions. The model is developed to optimize two objectives of water supply to downstream demand points and sediment removal from the reservoir through release control. The model is tested for the case study of Sefid-roud Reservoir in North of Iran which supplies water to several urban communities and agricultural lands and also suffers from significant storage loss due to high rate of sedimentation in the reservoir.

The impact of climate change and best management practices (BMPs) on flow and sediment load at a watershed outlet is presented in this study. Climate change scenarios include future daily temperature (maximum and minimum) and daily precipitation projections made by an Atmospheric Ocean Global Circulation Model (AOGCM) for the years 2046 to 2065. Daily precipitation data are further down-scaled to station level in the watershed area. An Optimal Control Model (OCM) developed by coupling a semi-distributed hydrological model, Soil and Water Assessment Tool (SWAT), with a genetic algorithm (GA) identifies the least cost design (sizes, types, and locations) of structural BMPs while meeting treatment goals at a watershed-scale for the years 2001–2005. Considering a requirement for 10% reduction of peak flow and sediment load for the years 2001 through 2005 and assuming the current landuse pattern will remain the same, the model is run with the current and future climate change scenarios; the performance of BMPs for two different time periods is compared. The model is demonstrated on Silver Creek watershed in Illinois.

The Muskingum method is one of the most common methods for flood routing in rivers. It is a relatively easy method with a few parameters specially for rivers with no detailed information on the hydraulic characteristics of the river reaches. Having a low number of parameters makes this method very easy to apply but the quality of its results will highly depend on the accurate estimation of the parameters. Multi-objective Particle Swarm Optimization (MOPSO) is a new optimization method which uses Pareto Dominance and crowding distance concepts for finding global optimal solutions of the Multi-objective optimization problems. In this study, the extended Muskingum method with multiple parameters which are variable with respect to the inflow range is used to rout the streamflows of Dez River in Khuzestan Province in southwest of Iran. The optimal values of the parameters are estimated using MOPSO method. The results of the case study have shown that the MOPSO model has been able to calibrate the Muskingum method and the routed streamflows show a close consistency with the observed streamflows.

The importance of a safe and reliable source of water is beyond question as a basic necessity of life. At the present time, water usages are normally included in agricultural, industrial, household, recreational and environmental activities. Dams/water supply reservoirs as an important parts of the water resource system have always been threatened by natural and manmade hazards. Therefore, due to the high vulnerability of dams' failure, it is necessary to use risk management methods in water resource management and planning. In this paper, a strategic planning scheme is used as a risk management approach and DPSIR methodology is applied to find the relation between different factors of the system and the most effective strategies. In the proposed methodology, risk based strategic planning is used for determining strategies and action plans for reliable water supply reservoir. The results show a paradigm shift is needed for a reliable supply of demands and replacing central water resources storage dams with high environmental, natural and accidental risk by distributed small water supply resources with low risks and environmental impacts. One of the important issues which should be considered in strategic planning is water quality as a state of the DPSIR (Driving force, Pressure, State, Impact, and Response) model.

U.S. National Weather Service (NWS) River Forecast Centers (RFCs) have produced hydrologic forecast ensembles for many years using historical precipitation and temperature as the forcing data for the ensembles. This has worked well for long lead-time ensembles of greater than thirty days. However, at least in the eastern United States, there is more interest in shorter lead-time ensembles, particularly in the period of three to seven days that convey hydrologic forecast uncertainty resulting directly from the uncertainties in precipitation and temperature forecasts. This paper will demonstrate the use of numerical weather prediction (NWP) model ensembles as the forcing for hydrologic models within the NWS River Forecast System (NWSRFS) Ensemble Streamflow Prediction (ESP) system. This approach makes it possible to produce probabilistic hydrologic forecasts that incorporate the skill and uncertainty of atmospheric models. While there are significant issues in directly using the meteorological ensembles, including biases, spatial resolution of the available data, and treatment of only a portion of all uncertainty sources, the approach allows for the generation of information for a time frame at which there is little current probabilistic hydrologic guidance available. This paper presents a description of a joint project among three NWS RFCs to incorporate ensemble forecasts from a variety of meteorological model ensembles. These include the National Oceanic and Atmospheric Administration (NOAA) NWS National Centers for Environmental Prediction (NCEP) Global Ensemble Forecast System (GEFS) and Short Range Ensemble Forecast System (SREF). The paper briefly outlines procedures to convert the incoming gridded ensembles into the necessary hydrologic inputs and discusses a variety of potential products that are being generated. We present a recent case study as a representative example. Finally, there is a discussion on how this project fits in with future ensemble forecast work including the NWS Office of Hydrologic Development (OHD), Hydrology Laboratory, Hydrologic Ensemble Forecast System (HEFS).

The National Weather Service (NWS) is moving toward a national Water Resources Outlook (WRO) based on the Ensemble Streamflow Prediction (ESP) system. ESP has been in use since the late 1980s and has been used in the Western Region of the NWS for many years to assist in water supply forecasts. With the implementation of the Advanced Hydrologic Prediction Service (AHPS), River Forecast Centers (RFC's) have been issuing 30- to 90-day probabilistic hydrologic forecasts for river forecast points using the NWS River Forecast System (NWSRFS) ESP system for almost a decade now. However, there has been no national product of being able to see how streamflows are expected to change in the coming months similar to what the United States Geological Survey (USGS) has for real-time data. In 2005, the Ohio River Forecast Center (OHRFC) developed a WRO based on USGS observed streamflow categories. In 2008, the WRO became an operational product of the NWS. The website is www.weather.gov/ohrfc/WRO.shtml The WRO uses current soil moisture states from the Sacramento Soil Moisture Accounting (SAC-SMA) model and short-term quantitative precipitation forecasts (QPF) from the National Center for Environmental Prediction's (NCEP) Hydrometeorological Prediction Center (HPC), the Climate Prediction Center's (CPC) 6- to 10-day, 30-day and 90-day temperature and precipitation outlooks, and the day 1 to 7 temperature departures from normal, which are derived from the National Digital Forecast Database (NDFD). A major push has been made to integrate climate forecasts into the Water Resources Outlook at OHRFC. By using CPC forecasts, the OHRFC ESP forecasts are able to modify the historical data (normal) and adjust to above or below normal categories to better reflect the current climate forecasts on a monthly to seasonal time-scale. In addition, in 2008, the NWS Western Region (WR) began developing a WRO based on percent of normal flows for the coming months. In late 2008, the OHRFC and WR methods were merged into a national format that is being expanded across RFCs. It is using Google GIS graphics combined with NWS forecast data for one to three months into the future. This merging of methods into a national product is being done based on a growing demand and positive feedback from many customers at the federal, state, local and private sector levels. The website is http://wateroutlook.nwrfc.noaa.gov. The goal of this national WRO is to provide a continuous water watch from past and present into the future months to assist a wide range of customers in decision making processes. It allows the customers to visually see and drill down into climate hydrologic forecasts. Significant upgrades and expansion of this product is expected as we work with our customers in 2010 and beyond. This project has support within the NWS as well as from our customers.

The Flood Monitoring and Warning Systems (FMWS) operating in real-time represent the main non-structural measures to be actuated for reducing risk in flood-prone regions. During the last years significant efforts have been addressed to improve the FMWS reliability also involving the issue of forecast uncertainty estimation. In fact, a deterministic system provides the user or the decision-maker with an "illusion of certainty" of the forecast quantity. Therefore, it becomes fundamental to quantify the level of uncertainty of the future estimates provided by the forecasting models which does not eliminate the uncertainty about the future flood wave evolution but only reduces it. Quantifying uncertainty enables the authorities to set risk-based criteria for flood warning, furnishes information for making rational decisions and offers potential for additional economic benefits of forecasts to every rational decision maker. In this context, the purpose of this study is to assess the uncertainty level to be coupled with stage values provided by a simple stage forecasting model of Muskingum type, named STAFOM-RCM model. It is currently operative within the FMWS developed for the Upper-Middle Tiber River basin in Central Italy and is based only on flood routing process incorporating a correction procedure based on the `Rating Curve Model', allowing to relate local stage and remote discharge without the need of a flood routing methodology. The model is tested for two river reaches considering a large number of flood events occurred in the last decade assuming as performance evaluation measures the Nash—Sutcliffe efficiency coefficient, the error on peak stage and time to peak and the coefficient of persistence. Moreover, the model uncertainty estimate is addressed by applying one of the most direct technique based on the analysis of the statistics of the forecasting model errors for a significant number of historical recorded events. The forecast stage uncertainty level is expressed in terms of confidence interval (CI) with an associated probability equal to 90% or 95%. The CI is differentiated on the basis of the stage values. Results show that the STAFOM-RCM model is able to provide accurate forecast stage hydrographs both in terms of peak region and stage hydrograph reproduction and that the methodology for CI estimate based on the statistic analysis of the model error can be applied when an extended series of observed variables is available. When the database is limited, as for high stage values, the estimation of the CI width could be wrongly affected. Therefore, particularly for high stage intervals occurring during severe floods the error probabilistic methods for uncertainty estimation should be used with care.

Stochastic rainfall generators are widely used in hydrologic analysis because they can provide precipitation input to models whenever data are not available. Rather than attempting to reproduce actual rainfall records, stochastic models aim at generating synthetic precipitation time series whose statistics match those of observed ones and, consequently, model calibration consists of determining the generator parameters that minimize the discrepancy between the two sets of statistics. It follows, therefore, that calibration can only be conducted at locations where rain gauges are available and rainfall statistics can be calculated. This paper addresses the following issues regarding stochastic rainfall generators: (1) Seasonality: The generator parameters should vary within the hydrologic year to reflect wet and dry seasons. A total of 12 models (one per month of the year) were developed, each of which had its own parameter set; and (2) Spatial variability. The generator parameters vary from point to point and show spatial patterns in their variability. Maps of the parameters for the entire United States were developed so that synthetic rainfall can be generated at any point in the United States. The application presented in this paper considers, specifically, the Modified Bartlett-Lewis Rectangular Pulse (MBLRP) stochastic rainfall simulation model.

A large number of dams, built in Italy in the last century, were sized using limited and in some cases sparse hydrological data. As a result, the design flood values were affected by this drawback to which it has to be added a poor knowledge of flood formation processes and statistical techniques used for that. In recent years, sophisticated statistical methods have been developed for the analysis of hydrological variables, and nowadays much more data are available. Therefore, these two aspects can be brought to critically review the hydrological safety of old dams. Considering the dependence between flood peak and flood volume, this study proposes a procedure based on a bivariate statistical approach to evaluate dam spillway adequacy. In particular, the one-parameter Archimedean copula, which has been found particularly useful in hydrology, was selected. Due to the limited number of data available for this study, a continuous hydrological simulation approach was also adopted in order to extend the available data with long synthetic discharge time series. This approach makes use of methodologies for stochastic generation of rainfall and temperature along with a continuous hydrological model for discharge estimation. The Montedoglio dam, a reservoir on the Upper Tiber River in Central Italy subtending an area of 267 km², was considered as case study. Starting from the synthetic and observed time series of discharge flood peak and flood volume available for this dam, the copula method was employed to determine the joint frequency distribution. From the two copulas (synthetic and observed), 1000 pairs of flood peak and volume were randomly extracted thus simulating the dam behaviour during its life time (i.e. 1000 years). These pairs were then transformed into discharge hydrographs, estimated considering the geomorphologic characteristics of the catchment. A third set of discharge hydrographs, directly derived from the synthetic time series, was also used for the analysis. Successively, the hydrological safety of the dam was evaluated by the reservoir routing of the three sets of discharge hydrographs, checking if the authorized maximum storage water level was exceeded. The results obtained with the three methods are quite similar allowing to assess the spillway adequacy for the investigated dam.

The research reported herein centers on long range streamflow predictability that originate in the State of Colorado. Specifically, we want to improve forecasting seasonal and yearly streamflows based on atmospheric-oceanic forcing factors, such as geopotential height and hydrologic factors such as snow water equivalent. We applied Principal Component Analysis (PCA) for forecasting at individual sites. The study included comparison of forecasts using various combinations of predictors, i.e. hydrologic, atmospheric, and oceanic variables. The study brought into relevance the significant benefits of using atmospheric and oceanic predictors, in addition to hydrological predictors, for long range streamflow forecasting.

Over the past century, the City of Boston has periodically experienced a decline in water table elevations and the associated deterioration of untreated timber piles which support building foundations. To combat declining water tables, Boston has instituted a groundwater conservation overlay district enforced by City zoning boards to require stormwater recharge practices for any new development or redevelopment project that increases impervious area. The primary goal of this research was to determine if such stormwater recharge best management practices (BMPs) have had an impact on groundwater levels in Boston. Recharge to the water table in Boston results from the infiltration of rainfall and snowmelt, leakage from water mains, and recharge from man-made systems (Aldrich and Lambrechts, 1986). As water providers in Massachusetts strive to meet requirements of Massachusetts General Law Chapter 21G, which requires unaccounted-for water (e.g. leaking water pipes) to less than 10 percent (<10%), investigations have been conducted to isolate and remediate leaking water pipes throughout the city. Given the high percentage of impervious cover area of Boston, the remaining sources of recharge are primarily man-made systems, including pump and infiltrate systems and stormwater recharge BMPs. The goal of this study was to determine the extent to which installed stormwater recharge BMPs have led to increased groundwater levels. To address this question, a regional multivariate regression model was developed to determine potential effects of recharge BMPs to observed groundwater elevations. Results indicate that selected recharge BMP explanatory variables have a slight but significant positive increase in observed groundwater elevations. This study reports on some of our initial results; extensive further analyses and testing are planned.

The National Oceanic and Atmospheric Administration (NOAA) currently (as of October 2009) forecasts that the southern Pacific Ocean will experience El-Niño conditions in late 2009 into 2010. Evaluating historic El-Niño events similar to the current conditions suggests that some regions of the U.S. including the Southeast, Midwest and Southwest, will see improvement in surface water supply, while others including the Pacific Northwest will experience below average water supply conditions. The hydrologic data consists of 639 unimpaired streamflow stations for the continental U.S. and approximately 300 western U.S. snowpack stations. To determine similar historic El Niño events to the forecasted 2009–2010 El Niño, two statistical tests were performed. A similar El Niño event was defined when the monthly historic Niño 3.4 conditions and forecasted 2009–2010 Niño 3.4 conditions had a coefficient of determination (R²) exceeding 90% and the t-test of the difference of the means did not exceed 90%. Four historic El Niño events (1972–1973, 1982–1983, 1986–1987, and 2002–2003) were found to be similar to the forecasted 2009–2010 El Niño event. Yearly standardized anomalies (i.e., mean of zero and standard deviation of one) of the streamflow and snowpack data were used to evaluate the fluctuations from the means for year (1973, 1983, 1987 and 2003) following the El Niño event. The hydrologic response included March 1^st, April 1^st and May 1^st snowpack and, seasonal and water-year streamflow. The results would be able to give recommendations to water managers regarding projected changes in water supply and the impacts to reservoir operations. Given the timing of the 2010 ASCE EWRI Conference (mid May), current 2010 hydrologic response will be compared to predicted (i.e., 1973, 1983, 1987 and 2003) response.

An important problem in water resources engineering is the estimation of the flood magnitude for a certain return period. In flood frequency analysis, an assumed probability distribution is fitted to the available sample data to estimate the flood magnitude at the upper tail corresponding to return periods which are usually much larger than the record length. In most cases, the selection of an appropriate probability distribution is based on goodness-of-fit tests. However, previous goodness-of-fit tests give equal weight to differences between empirical and theoretical distribution functions corresponding to all the observations. In this study, the modified Anderson-Darling test statistics which can give different weights to given data are provided using simulation. And the regression equations for the modified Anderson-Darling test statistics are derived as a function of sample sizes and significance levels for the generalized extreme value and generalized logistic distributions.

Regional flood frequency analysis is widely used to overcome shortcomings of at-site analyses resulting from insufficient record lengths and to estimate flood quantiles at ungauged sites. This requires the delineation of homogeneous regions in which the flood regime is sufficiently similar to allow the spatial transfer of information. It is generally accepted that this hydrologic similarity is due to similarity in basins' physiological characteristics; however, because of nature's complexity and variability in flood producing mechanisms, this is often not the case. In addition, as currently practiced, the delineation of homogeneous regions is highly subjective, and delineated regions are highly dependent on the similarity measures and classification techniques employed. Moreover, current methods can only be applied with confidence to gauged basins as they allow subsequent testing for homogeneity. The goal of this research is to improve the delineation of homogeneous regions for regional flood frequency analyses by identifying the physical controls of hydrologic homogeneity. The study presented herein employs 480 USGS flow gauges located in the southeastern region of the United States. Multivariate statistical methods are used to identify key basin characteristics, and to quantify their individual or combined impacts on region formation. Preliminary results suggest mean basin elevation, soil moisture, and basin slope determine to a large degree the hydrological behavior of a watershed and therefore should be given considerable attention when forming hydrologically homogeneous regions in these states.

The present investigation modifies the "Region of Influence" (RI) approach based on statistical and physical characteristics of the stream gauging stations in south eastern New South Wales (NSW), Australia. Statistical properties of flood data are first included as the attributes in similarity distance algorithm instead of geographical location. The RI approach is modified by the determination of the criteria for the choice of a set of six statistical attributes of catchments. The choice of the threshold value of the similarity distances and the effect of attribute interaction are also discussed. The modified method was then applied to determine the RI of some streamflow gauging stations in NSW using three independent statistical attributes. In regional flood frequency analysis, the defined regions must be homogeneous. In this study, the physiographic characteristics of catchments are also combined with flood statistics in terms of defining the RI for the selected sites in NSW, Australia, in order to develop optimally the RI approach. This approach transfers the relevant information from the dispersed catchments in the region to their reference site. Three independent physical attributes, Median Annual Rainfall, Coefficient of Compactness and Stream Length, and three independent statistical attributes, Coefficient of Variation, Q50/A and a new coefficient based on Pearson distribution as the statistical attributes are also applied, for defining the RI of each site. When physical attributes are included in the attributes set, sites in the resulting regions are more concentrated around the reference site. The results of this study indicate that a physically-statistically based RI approach can provide a more effective information transfer than a RI approach which only includes flood statistics. Thus, the physically-statistically based RI approach is recommended for flood regionalization.

According to the research using GCM, it is predicted the intensity of storm becomes stronger than ever in most of the area in the Northern hemisphere. Conventional frequency analysis assumes that rainfall series is stationary, however, in practice, all of the rainfall series are not stationary. This assumption could misguide result of frequency analysis. Several studies have tried to consider nonstationarity to regional frequency analysis. Regional frequency analysis which can complement the problem of lack of the number of observations is known as more stable method than at-site frequency analysis. This study selected the rain gauge stations whose rainfall series shows non-stationarity and stations are geometrically close to the stations. In order to consider non-stationarity of rainfalls, this study applied high correlation between parameters and mean of cumulative annual maximum rainfall to process of parameter estimation. Based on this, probability distribution of the specific point in the future can be estimated.

The research presented here employs a quasi-analytic Bayesian analysis of the Generalized Least Squares (GLS) regional hydrologic regression framework introduced by Reis et al. [2005] and Reis [2005], and extended by Gruber et al. [2007] and Veilleux [2009], to develop a regional model of skewness coefficients for the State of California. To correctly analyze the State of California data set with the large estimated cross-correlations, alternative statistical procedures were developed to provide stable and defensible results. In addition, special attention is devoted to the impact of low outlier screening and the inclusion of historical information on the variance of the sample skewness estimators. A non-linear model employing mean basin elevation provided the best description of the log-space skews of the annual peaks in 158 California peak flow series. This model was reasonably accurate with MSE = 0.13, and model error variance of only σ_δ²= 0.10, corresponding to an estimate with an effective record length of 60–70 years at most sites.

There is popular perception driven by statements in authoritative literature that heavy rainfalls have become more frequent, and that this trend will increase with global warming. Most of the scientific literature examines this question from the point of view of climatology using definitions of "heavy", "very heavy", or "extreme" rainfall, which are different from those commonly used by civil engineers and municipal, state and Federal planners. This difference in semantics has lead to a gap in the understanding of impacts of climate change on precipitation frequency estimates. This paper identifies the differences in semantics used by the climate and civil engineering communities and examines trends in the observed record in precipitation frequency estimates. We use terms recognized as the basis for design of the Nation's civil infrastructure. Specifically, we look at trends in the number of exceedances of thresholds for a variety of precipitation frequencies and event durations, with thresholds taken from Volumes of NOAA Atlas 14, "Precipitation-Frequency Atlas of the United States" (Bonnin et al, 2006a, 2006b). We quantify observed trends and place them in the context of uncertainty associated with the precipitation frequency estimates themselves. NOAA Atlas 14 provides precipitation frequency estimates for the U.S. and is the source of Federal, civil engineering, probabilistic design standards for rainfall, and for the regulations issued by many Federal state and local governments.

Inter-event Time Definition (i.e., minimum dry period between storm events, or IETD) is a very crucial parameter that is often neglected in the analysis of rainfall time series. Based on an IETD, a long-term rainfall record can be analyzed for different storm event characteristics such as rainfall event volume, duration, intensity and inter-event time. The design storms adopted considering IETD can influence the stormwater storage decisions within urban watersheds. Moreover, current interests in the low impact development (LID) require careful analysis of rainfall and runoff volume in the analysis and design of best management practices. The current study proposes an investigative study of antecedent storm event characteristics for different climatic regions within the United States based on varying values of IETD. In this paper, the focus is placed on analyzing the long-term rainfall record to assist in the better quantification of the characteristics of catchment conditions antecedent of a design storm. The design storm might be applied for the design of stormwater management facilities. More specifically, this research aims at the evaluation of the probabilistic characteristics of the total volume of precipitation that has occurred over a time period preceding a runoff-producing event.