World Environmental and Water Resources Congress 2007: Restoring Our Natural Habitat

Eight watersheds spanning a gradient of urbanization were used to identify linkages between indicators of aquatic ecosystem health and hydrologic and geomorphic metrics derived from a 20-year continuous stream flow record. The geomorphic metric used to evaluate linkages is erosion potential calculated using excess shear stress, which describes the energy exerted on the stream channel that is capable of causing bed scour and bank erosion. The hydrologic metric used to evaluate linkages is the duration of time that in-stream flows are above the 0.5-year return interval peak discharge rage, which is a measure of stream flashiness. The 20-year continuous stream flow records for each watershed were generated using EPA Storm Water Management (SWMM5) Models calibrated to 18 months of measured flow data. A benthic index of biotic integrity was used as one indicator of aquatic ecosystem health, and was calculated from aquatic macroinvertebrate sampling data collected by the United States Geological Survey in the eight watersheds, ranging from three to eight square miles in size. Various land use and stormwater management practices were modeled in one of the eight gradient watersheds to determine the effect of these practices on the hydrologic and geomorphic metrics. The influence of development density (percent imperviousness) and of land use patterns, such as the proximity of dense urban development to stream corridors and headwater development versus downstream development, on hydrologic and geomorphic metrics was examined. Additionally, the effects of stormwater management practices such as traditional stormwater detention, water quality control and low impact development on hydrologic and geomorphic metrics were also examined. Hydrologic and geomorphic metric values generated by the various practices were compared to those generated along the urbanization gradient to identify the management practices that best generated conditions favorable to meet ecologic targets.

Rainfall and runoff data for a 3.08 square mile urban watershed in Denver, Colorado was used to investigate the effects of raingage density and hyetograph compositing on urban stormwater runoff simulation. This watershed has rainfall data from five raingages and flow data from two gages, all in 5-minute time increments. The data were used to calibrate the EPA Storm Water Management Model (EPA SWMM, version 5.0), and the Urban Drainage and Flood Control District's version of an earlier EPA SWM model (UDSWMM). This calibrated model served two purposes; first, to examine the effects on runoff calculations using a single composite hyetograph for each of the recorded storm rainfall and runoff events modeled and second, to determine the effects of raingage density on volume of runoff and peak flow simulations. The effects of raingage density were investigated by processing rainfall data from each raingage using several different combinations of raingage densities. The data were used to drive the calibrated SWMM model and the results compared against recorded runoff volumes and flow rates for the recorded storms. It was demonstrated that raingage density does affect the accuracy and the scatter of simulated results. The effects of compositing recorded rainfall data at several raingages into a single rainfall hyetograph were also investigated. Two types of compositing were performed. One method simply used area weighted averaging of rainfall recorded at each time increment. This method was defined as straight across compositing. In the second method, each hyetographs at the five gages was examined and all values were time shifted to line up the most intense five-minute rainfall values of the storms. The simulation results were then compared to the recorded flows This paper describes the findings of this study and discusses their implications for urban stormwater runoff modeling. It presents a summary the collaborative work and findings by the authors over the last 17 years.

The City of Frontenac, Missouri, has become the stormwater management leader in the St. Louis Metropolitan Area by requiring single-lot residential developers to mitigate the effects of increased impervious area. Frontenac is developing a comprehensive stormwater master plan to ensure that the impacts on stormwater runoff due to recent development and future infrastructure are addressed. The consequences of development are analyzed and the impact of Best Management Practices on the City's watersheds is evaluated. The discussion of Best Management Practices will focus on infiltration. Rain gardens in particular will be evaluated in this paper, though other infiltration practices are being implemented as well.

One approach for improving the quality of stormwater runoff before it enters the receiving water is to install stormwater best management practices (BMPs). Stormwater BMPs include a wide range of systems (rain gardens, ponds, wetlands, underground proprietary sediment removal devices, etc.) used to reduce stormwater runoff quantity or improve stormwater quality, or both. No standard methodology for the assessment of stormwater BMPs is available. Therefore, we propose a tiered approach to stormwater BMP assessment that is termed the "Four levels of assessment" (Table 1), that are numbered in order of increasing difficulty and cost. Developers of an assessment program should consider each of the four levels of assessment in order, and consider advancing to the next level only when requirements of the assessment program have not been satisfied. All stormwater BMP assessment programs should include regularly scheduled (at least annual) visual inspections (level 1). In addition to visual inspections, capacity testing (level 2) and/or simulated runoff testing (level 3), if warranted, should be included in stormwater BMP assessment programs at regular intervals to determine the performance of a BMP immediately after installation and to determine how performance of a stormwater BMP is changing with respect to time, changes in the watershed, or both. If the goals of the assessment program cannot be met by capacity testing or simulated runoff testing, or these techniques are not feasible, then monitoring (level 4) should be implemented as part of the assessment program.

A gravel wetland, designed and constructed, by the University of New Hampshire Stormwater Center is demonstrated to outperform other technologies in stormwater management. Gravel wetlands have sparse published data in stormwater management and minimal design guidelines exist for them. They have been occasionally used as lined systems in lieu of septic systems. The subject gravel wetland was monitored side-by-side with a range of other stormwater technologies, and was routinely the top performer for year-round water quality improvements and storm-volume reduction. This system was designed as a series of horizontal flow-through treatment cells, preceded by a sedimentation basin (forebay). The technology is designed to retain and filter the entire Water Quality Volume (associated with the first one inch of rainfall runoff from an impervious surface): 10% in the forebay, and 45% in each of the respective treatment cells. For the small, frequent storms, each treatment cell filters 100% of the WQV. Gravel wetlands are designed as flow through treatment, where the stormwater passes through a gravel substrate that is a microbe rich environment. Side slopes should be 3:1 or flatter for maintenance, as standing water of significant depth is not expected other than large rainfall events. The wetlands should be continuously saturated below a depth of 10 cm from the ground surface in order to promote near-anaerobic water quality treatment conditions and to support wetland vegetation. To force this near-surface ground water condition, the system outlet pipe has an invert 10 cm below the wetland ground surface. In the event of a high rainfall event, the water quality volume is stored above the wetlands, and drains into a perforated riser on one end of the wetland, and into the substrate. Seasonal performance evaluations indicate that the gravel wetland routinely achieves close to 99% removal efficiency for total suspended solids, total petroleum hydrocarbons-diesel, and zinc, and > 80% for nitrate. Additionally, the subsurface nature of the system results in minimal seasonal stormwater treatment variations for such a northern climate.

Stormwater best management practices include the installation of a variety of water quality improvement devices to treat urban stormwater runoff. Several of these devices occur within a 1km stretch of an upper urbanised creek catchment. The main channelised stream flows into a sediment basin, then into a constructed wetland, followed by a second deeper wetland. The latter also receives stormwater through a piped drainage system after it passes through a below ground GPT. A minor tributary receives stormwater through a piped drainage system, which also passes through a GPT before entering a natural densely vegetated riparian wetland. The water from both tributaries converges and flows downstream through a natural channel and series of lagoons. The aims of the research project were to determine spatial and temporal changes in pollutant concentration during wet and dry weather and; to assess the effectiveness of the "treatment train" in removing nutrients and suspended solids. Water quality parameters monitored included total and volatile suspended solids and nutrient speciation. TSS in stormwater runoff entering the sediment basin within 12 h of storm event was highly variable and TVS was about 25%. There was little reduction in TSS along the treatment train. However, within 24 hours of a storm event TSS in stormwater had decreased to background concentrations, but was still higher in the wetlands. Higher TSS in the wetlands also occurred in dry weather suggesting resuspension (caused by ducks) of both sediment and organic particulates (TVS was about 50%). TSS was consistently reduced in the downstream natural stream channel. During storm events NH₄ increased in Wetland 2, but NO₃ and PO₄ were reduced. Highest concentrations of NH₄, NO_x, PO₄ in both wet and dry weather were from piped outlets (in particular those from the below ground GPT's). In dry weather, NO₃ concentrations were reduced in the wetlands and natural stream channel. Our study concluded that during storm events the treatment train has little effect on the removal of TSS due to the high flow and short detention times, but some reduction in nutrients did occur. Nutrients in piped drainage were always higher than in the open stream channel suggesting periphyton in the channelised streambed were probably effective in removing dissolved nutrients. The 600 m length of remnant natural channel, lagoons and associated vegetation was effective for water quality improvement in post storm and dry weather. This serves as a reminder that the retention of natural stream channels and buffers of riparian vegetation are an integral component of Best Management Practice for urban stormwater treatment in many catchments.

The Villanova University constructed stormwater wetland (CSW) has been an active research facility since 2000 and is a capable at storm flow reduction and water quality improvement. While successful, the present system may not be the optimal design. We develop a model to serve as an effective tool to examine various, proposed solutions to create an efficient CSW system. In this case, the existing configuration is used as a reference to develop and calibrate a model describing the system's flow regime and performance. The model is extended to simulations of flow through different wetland configurations, to quantify the effects of wetland design on hydrodynamics and determine the optimal design for a CSW. Additionally, as baseflow accounts for 50% of the yearly flows within a CSW, both storm event and baseflow conditions are simulated to determine optimal design for stormwater control and pollutant removal over a full range of flow conditions.

Microbial contamination from fecal origins in stormwater runoff poses a risk to human health through the consumption of drinking water and recreational and bathing contact with surface waters. Indicator bacteria serve as the regulatory meter by which water quality is measured and water quality standards (WQS) must be met. Research on constructed wetlands inactivation of fecal indicators in secondary and animal wastewater is well documented. Removals of fecal streptococci and coliforms generally exceeded 80% and 90%, respectively, in a review by Kadlec and Knight, 1996. Gersberg et al. and Garcia and Bécares concluded that extensively vegetated systems remove indicator bacteria at significantly higher rates from wastewater than unvegetated systems. However, because of the potentially high indicator bacteria concentrations in stormwater runoff, the untreated fraction in effluent from retention ponds and constructed wetlands may increase receiving water concentrations beyond WQS. This is in contrast to separate sanitary systems and combined stormwater and sanitary systems which, other than during sewer overflow conditions, chemically treat the wastewater routed to treatment plants. Experiments to evaluate the use of the first-order decay function for predicting indicator bacteria concentrations in effluent from best management practices (BMPs) were designed and completed by U.S. EPA's Urban Watershed Research Facility in Edison, NJ. Two studies, one at the bench-scale and the other at the pilot-scale, were completed to determine similarities and differences in inactivation rate constants, coefficients, and affects of environmental conditions on bacterial indicator concentrations. The focus of this paper is on the results of the pilot-scale studies which specifically explored the environmental factors that influence the rate of microbial inactivation as urban stormwater passes through retention ponds and constructed wetlands. The mesocosms designed and constructed for this project offered a unique setting allowing many characteristics associated with stormwater and flow to be held constant (i.e., influent characteristics, residence time, and pollutant loading). By varying testing dates with climatic conditions experienced throughout the year, an assessment of the impact of the environmental change on bacterial inactivation rates could be assessed. The results allowed comparison of rates of inactivation with seasonal wet-weather events and were used to determine new inactivation coefficients based on environmental variables. More information is needed to determine whether models that use first-order decay functions when predicting bacteria effluent concentrations from field BMPs (usually as a point source) are accurately providing effluent predictions and concomitant loads. Results suggest, depending on how bacterial loading is modeled during total maximum daily load (TMDL) development, that first-order decay may not adequately consider background concentrations when calculating dry-weather loading. Similarly, predicting loading over longer durations while ignoring seasonal changes may result in less accurate predictions of indicator bacteria loading. Both outcomes may impact actual bacterial loading and risk to human health with exposure to stormwater runoff contaminated water.

An existing detention basin was retrofitted to an extended detention basin through the outlet modification. Since bottom of the existing basin was covered extensively by vegetation, it served as the surface wetlands as well. Therefore, the basin after outlet modification became an extended detention basin with dual flood control and pollutant removal functions as well as the surface wetlands with advanced pollutant removal function. It was determined that the retrofitted extended detention-surface wetlands system would be as efficient as other retrofit alternatives in pollutant removal. Sustaining such a system would eliminate the additional retrofit costs, reduce the long-term maintenance costs, and prevent the adverse upstream flooding impacts. Water quality performance of the retrofitted extended detention-surface wetlands system was monitored and evaluated. The retrofitted basin achieved excellent total suspended solids removal and reasonably good nutrient removal.

This paper provides an overview of Gwinnett County's ongoing watershed protection program and describes the implementation of several proposed projects whose goal is to improve water quality and aquatic habitat. These projects include two wet detention ponds, Lakes Marie and Wethersfield, and a stream restoration project located on a tributary of Bromolow Creek. A summary of each project's goals, an overview of the design, and a review of the estimated project benefits and costs of each will be presented. The goals of each project are intended to be consistent with Gwinnett's watershed protection program, which has now gone full circle from planning to implementation.

Infiltration best management practices (BMPs) are becoming an increasingly common measure to meet stormwater volume reduction regulations. One such BMP is an underground infiltration bed, which temporarily stores runoff that slowly seeps into the underlying soil. While these BMPs are extremely effective, especially in areas heavily developed and areas with tight space constraints, modeling the system to predict the anticipated infiltration can be difficult. A common method used to calculate infiltration is the Green and Ampt Equation. This physically based approach uses hydraulic conductivity, suction and depth of the wetting front to calculate the rate of infiltration. The difficulty with modeling this approach is that soil properties vary from site to site and even within a site, and the infiltration rates are affected by temperature, moisture content, and depth of ponded water. As part of the research into the performance of underground infiltration BMPs, a model was developed that allows the user to adjust the factors in the Green and Ampt equation for both the temperature of the water and the moisture content of the soil. This allows the user to examine the BMP's performance under a variety of field conditions providing a more realistic estimate of the infiltration. This model was verified using three years of data collected from the Porous Concrete Infiltration BMP at Villanova University. The initial conditions for each modeled storm were used as input parameters for the model and the resulting relationship of ponded depth versus time was compared to the recorded data. For comparison, the standard Green and Ampt model was also run. The developed model showed up to a 99.53% improvement over the standard model in predicting the infiltration from the subsurface infiltration bed. Various sensitivity analyses were performed as well as statistical analyses of the results.

A field evaluation of the Filterra® Stormwater Bioretention Filtration System was performed to: 1) determine removal efficiency information based on field data, which is inherently more variable than laboratory data, and 2) to compare the observed field efficiency with the efficiency determined in the laboratory. Inlet and outlet pollutant concentrations from a Standard 6' x 6' Filterra® System were monitored between October 19, 2004 and November 22, 2005. The pollutants of interest were Total Suspended Solids (TSS), Total Phosphorus (TP), Total Kjeldahl Nitrogen (TKN), and the heavy metals cadmium, copper, lead and zinc. Monitoring data were then evaluated to determine appropriate Efficiency Ratios. Raw data were first evaluated to determine if they were normally distributed. If so, the Efficiency Ratio was determined based on the Event Mean Concentrations of the influent and effluent samples. If the raw data were not normally distributed, the Efficiency Ratio was calculated using the Event Median Concentrations. Results show the following average efficiency ratios: TSS 85%; TP 55%; TKN 20%; Cu 16%, and Zn 50%. Statistical significance and seasonal variations of the removal efficiency were also examined.

Filtration of stormwater runoff is becoming an increasingly popular method to treat stormwater in order to meet water quality goals set by various agencies throughout the United States. In a broad sense, filtration refers to an array of technologies including sand filters, media filters, bio-filtration, bio-infiltration, and surface and subsurface infiltration. Though highly effective technologies, the downside of these technologies can be clogging by waterborne sediments. Despite the wide spread practice of applying these technologies there are few studies relating to how they will react to loading of solids associated with stormwater runoff. Solids loading onto the surface or within the matrix of a filter will have a substantial impact on the life and performance of a system. This paper presents a general overview of sediment loading characteristics on and within filter beds, and presents a case study of laboratory based loading of filter media. This paper also outlines how mass loading governs the operation and maintenance of a filtration technology and provides design guidelines that have been utilized for sizing on a mass load basis rather than a flow basis.

Stormwater managers use infiltration to promote groundwater recharge in urban areas and to reduce the volume and flow rate of stormwater runoff created by post development conditions. However, the potential for groundwater contamination exists. Studies have shown that some areas are more prone to groundwater contamination than others. As a result, methods for easily predicting contamination potential beneath infiltration devices are being developed. One such method involves the use of computer programs, such as SESOIL — a one-dimensional vadose zone model. SESOIL was selected because of the multitude of processes available in the program for predicting pollutant removal. SESOIL was first evaluated using a full factorial design, considering six potential factors that were thought to influence the predictions (rainfall, concentration, vadose zone thickness, intrinsic permeability, soil pH, and soil organic matter. The results showed that, at the concentrations typical of urban stormwater runoff, only rainfall, concentration and intrinsic permeability were important. Difficulties of application were encountered due to a lack of available input values and data sets. Therefore, laboratory research on partitioning factors between the water and the soil were undertaken. The results showed that the partitioning coefficients calculated from the removal of pollutants from a multicomponent mix at typical stormwater concentrations were similar to the low range found in the literature. However, the literature did not have values for sparingly-sorbable compounds such as the nutrients. This research is using a vadose zone model, such as SESOIL which incorporates these numerous chemical reactions in the calculations, as a design tool for infiltration devices with both engineered and natural soils. This research will support the development of guidance for protecting groundwater from unintentional contamination by stormwater runoff passing through an infiltration structure.

Stormwater is an important environmental concern. Constructed Stormwater Wetlands (CSWs) are at tool in stormwater management, however little is known about the dispersion coefficient in laminar flow conditions. This study replicates two laboratory studies examining the dispersion coefficient as it relates to the plant density in laminar flow conditions. Nepf et al. examined plant densities from 0 to 5.3% and Serra et al. examined plant densities between 10 and 30%. The Villanova University field study examined plant densities between 3 and 10%. The present experiment provided the opportunity to examine the gap in plant densities and examine the effect of field conditions. The results indicate that the dispersion coefficients from the field experiments are one to two orders of magnitude higher than the laboratory experiments. The hydrodynamic modeling software Mike 21 is being used to confirm and quantify this theory.

This paper will present results of a proof of concept evaluation of the Dual Stage Filter to enhance inorganic nitrogen removal from stormwater. The design of the Dual Stage Filter provides two separate stages of granular media filtration, both of which employ ion exchange media and biological regeneration of ion exchange sorption sites. The first filter stage is operated in downflow mode and contains chabazite. During continuous and storm event loadings, ammonia is retained in the filter by sorption onto the chabazite. Microorganisms attached to the chabazite convert ammonia to nitrate, and biologically regenerate ion exchange sites on the chabazite. The second filter stage is directly coupled to the first stage and operates in upflow mode, treating first stage effluent. The second stage includes a mixed granular media of anion exchanger for sorption of nitrate and nitrite, and electron donor for denitrification. Nitrate entering the second filter stage includes both nitrate that is biologically produced by nitrification in the first stage, and nitrate in influent that passes through the first stage. In the second stage, nitrate is adsorbed by the anion exchange media and the sorption capacity is regenerated by denitrification. Materials balances and effluent quality will be used to characterize the performance of this new BMP for inorganic nitrogen removal, and to assess the potential to incorporate the Dual Stage Filter into more comprehensive treatment trains.

This study examined the event-based performance of an empty-sump screened hydrodynamic separation (HS) for particulate matter transported in rainfall-runoff from a source area urban watershed. Fully-captured runoff events were examined and the entire volume of runoff and particulate matter from each event was treated by the HS. The ability of the HS (in this case continuous deflective separation) to reduce particulate matter loads in rainfall-runoff was quite variable and was largely a function of the runoff granulometry and hydraulics. The HS was subject to highly variable hydraulic (flow rate) and hydrologic (duration, intensity) event characteristics, and the coupled variability of granulometry. The HS was cleaned after each event so that scour and discharge of previously captured particulate matter could be separated from event-based discharges. Given the variable clarification mechanisms of a HS, results demonstrated that a clean HS provided good separation capability for the coarse sediment fraction (> 75 μm), much less separation for the settleable fraction (25~75 μm) and low separation capacity for the suspended fraction (1~25 μm). Results consistently indicated that the mass fraction of sediment and settleable particles also increase compared to suspended particle fraction indicating a positive relationship between particle concentration and coarser particle size distribution (PSD). Such coupling and generation of coarser PSDs help explain the improved results at higher flow rates. Study results were representative of the flow and granulometry with the full cross-section of flow sampled and the entire gradation measured. Results indicate that the coupling of hydrology and particle transport influences particle size distributions (PSDs) in runoff flows. This study clearly demonstrates that performance by the HS was predominantly influenced by influent PSD far more strongly than hydraulics. The role of scour is not reported herein.

The purpose of the current study is to examine the ability of different sorption media to sorb nitrogen from stormwater contained with various nitrogen fertilizers. Sorption media of interest include but are not limited to tire crumb, sawdust, activated carbon, iron amended resins, orange peel, peat, leaf compost, naturally occurring sands, zeolites, coconut husks, polymers, and soy bean hulls. The study consisted of running both batch and packed bed column tests to determine the sorption capacity, the required sorption equilibration time, and the flow through utilization efficiency of various sorption media under various contact times when exposed to stormwater contaminated with various nitrogen fertilizers. Based on such findings, as a State-wide unified rule for stormwater management is developed there is a need to combine field and laboratory data for designing effective passive in-situ treatment units within stormwater retention/detention ponds for ultimate control of nitrogen impact on groundwater in Florida. This paper presents a general description about the upcoming large-scale study in both laboratory and field campaign. To address the uncertainty a simulation model will be designed to address the reliability of such a passive in-situ treatment system as well.

Defining collection system performance criteria is a critical step in the master planning process because it sets the metrics by which existing collection system infrastructure will be evaluated to meet level-of-service goals by which future facilities will be designed. It is important to recognize the difference between planning criteria and design criteria for judging the performance of collection system infrastructure. Planning criteria relate to those metrics that are used to analyze the adequacy of existing facilities and to project future infrastructure needs for financial planning purposes. These criteria are not intended to provide the same expected levels of safety and protection that design criteria provide. It is generally inappropriate to use standard design criteria as planning criteria, especially when significant wet weather flows impact an existing collection system (as is the case with an aged combined sewer system). For example, new sewers are designed to convey flow under non-surcharged conditions, while surcharging may be permissible during the analysis of existing sewers, especially during wet weather flows. Wet weather flow may dramatically affect the performance of collection systems. Master planning collection system infrastructure requires an assessment of the performance criteria used to size the systems during wet weather flows. Determining how to measure the performance of existing facilities and deciding on a design event or condition, or level of service, for wet weather planning may not be straightforward. This is especially true when basing the performance on an expected flow duration series. Literature and regulations offer little guidance on the design condition or design flow event frequency to use. Choosing a large event can incur significant capital costs, while too small of an event may lead to unacceptable overflow frequency and volume. This paper examines collection system performance criteria for both planning and design purposes that can be used for completing modeling analyses and identifying capital improvements. The planning and design criteria help define the type, location, and extent of the facility deficiencies that should be corrected to maintain service reliability. Criteria for dry weather flow as well as wet weather flow conditions caused by infiltration and inflow are included. Examples are included to illustrate how results can vary from one approach to another, and affect the extent of capital improvements as well as the level service of the collection system.

Management of sanitary sewer collection systems is a complex, multifaceted undertaking. Major and even smaller utilities can be responsible for the operation and maintenance of hundreds of miles of sanitary sewers, manholes and pump stations. Because of potential pollutant loading to receiving waters during wet weather events from Sanitary Sewer Overflows (SSOs), many utilities are now focusing on the management of their collection system in a comprehensive manner under so-called Capacity, Management, Operations, and Maintenance (CMOM) type programs. The primary goal of CMOM is to minimize SSOs. This is accomplished by a comprehensive management program, which includes an inventory and sewer system evaluation survey program for establishing the location and condition of the sewer, development of hydraulic models for determination of system capacity, development of Standard Operating Guidelines for better operation of the system, and ongoing repairs and maintenance. This paper describes experience of various projects undertaken within Fulton County, Georgia under the County's CMOM program. A number of projects are evaluated in terms of the key elements and costs of the projects and reduction in impacts on the water resource system.

Storm tanks at Wastewater Treatment Works (WwTW) are an essential but often neglected component of the sewerage system and in combined systems they provide relief to the WwTW at the time of storm events. Historically in the UK approximately 6 times mean daily dry weather flow (DWF) is discharged to the works with approximately half the inflow — circa 3 times DWF — being discharged to the storm tanks. Once the tanks are full the excess flows are spilled, untreated, to the nearest watercourse or ocean. After the storm event has subsided and the DWF returns to normal, the storm tanks are emptied to the works with the effluents given full treatment. It may be argued that in recent years, the design philosophy for storm tanks has been static, certainly in the UK, and has not moved forward in the same way as other developments associated with integrated quantitative and qualitative modelling of sewer systems and the performance of other ancillary structures. It is common practice for the pollution retention performance of storm tanks to be omitted from regulatory guidelines and hence there is little need to understand what is actually spilled to the receiving water. The design of tanks is usually based on a volume of effluent to be stored but little is known about how the tanks retain pollution or of the subsequent impact that the spilled pollution has on the receiving waters. New legislation in Europe, in the form of the Water Framework Directive, will require all water utility companies to better understand the magnitude, volume and quality of all intermittent discharges that issue from sewerage systems into receiving waters. This approach is recommended at the integrated catchment scale and hence the contribution to receiving waters from storm tanks may form one of the major elements of pollution. This paper describes a review of current practice and presents results of an experimental programme which improves understanding of the hydraulic and pollutant retention performance of storm tanks. This is based on UKWIR research project WW22B.

Communities throughout the United States are spending billions to manage wet weather flows. Regulatory programs now address the full range of wet weather issues, including combined sewer overflows (CSO), sanitary sewer overflows (SSO), stormwater and wet weather effluents from wastewater treatment plants (WWTPs). In some cases, such as the management of stormwater quality, specific performance requirements e.g. effluent limits have not as yet been broadly applied. In other instances, such as CSO satellite treatment or treatment of wet weather flows at WWTPs, the facility operating permit specifies capacity and treatment requirements. Both facility designers and operating authorities face considerable challenges in this environment. One such challenge is the uncertainties associated with wet weather facilities design and sizing. Another is the need for post-implementation monitoring to assess facility performance aimed at meeting requirements stipulated by regulatory authorities in operating permits. Wet weather testing and verification when conducted in advance of design is employed to predict performance under various operating conditions, to the set appropriate limits for the range of operating conditions and to facilitate the development of a design meeting desired objectives. Wet weather testing and verification can serve a second purpose, that of compliance assessment. This activity addresses the evaluation of facilities under actual operating conditions and is every bit as challenging than pre-design evaluation. The purpose of this paper is, therefore, to present a systematic, scientifically based approach for compliance assessment with specific reference to CSO and WWTP wet weather treatment facilities.

The best management practices (BMPs) are generally designed at the site-scale to meet the regulatory requirements for their pre and post-construction performance. In large-urban drainage systems, however, the performance objectives of BMPs may be targeted far downstream of where they are located. The integration of BMPs into urban drainage models becomes critical. In this paper, the issues related to application of a large-scale model to represent BMP performances are discussed, along with an example of an environmental impact study performed for a green building development in New York City. The recommendations for improvement of urban drainage models in terms of BMP representations are also presented.

In most countries the principal assets for the conveyance of surface water runoff in the urban area are sewers. In older urban areas the sewer systems are mainly combined where domestic and industrial effluents are conveyed in the same pipes of the system. Combined sewer overflows (CSO's) are constructed to relieve the system of the excess flows that cannot be accommodated by the downstream sewers or the treatment works, thereby reducing the risk of surcharge and surface flooding in the catchment upstream of the CSO. A primary function of such CSO structures is to retain the pollution within in the combined sewer flow such that it is discharged to the treatment works. Such pollution comprises aesthetics (floaters), finely suspended solids and pollutants in solution. Current practice has seen the use of storage tank structures to retain these pollutant effluents in the system but it has recently been recognised that, for the retention of aesthetic solids, the inclusion of storage may not be the most cost effective option and that new screening technologies may be employed to retain and treat the pollutants in the flow prior to its discharge to the receiving watercourse. This paper describes a study that has been completed to monitor the performance of a static screen to retain aesthetic solids in a CSO chamber.

EmNet, LLC, the City of South Bend, IN, the University of Notre Dame, and Purdue University have developed CSOnet, an embedded sensor network that provides decentralized real-time control (RTC) for CSO abatement. Unlike conventional centralized RTC systems, CSOnet implements optimal control strategies using a distributed network of microprocessors rather than a massive central computer, which results in a system that is robust, incrementally implementable, cost-effective, and easily integrated into any existing infrastructure. CSOnet was demonstrated during a pilot demonstration, which increased the storage ability of a retention basin by up to 110% and cost 55% less than conventional solutions. Furthermore, in a series of computer simulations, CSOnet was able to reduce the amount of overflow by up to 84% through interceptor optimization, to significantly reduce the number of CSO events, and to prevent dry weather overflows.

An investigation was carried out to investigate the flood potential at a proposed residential development located in Indio, California. The existing floodplain area adjacent to the project area is designated to receive flood flows originating from Thousand Palms Wash, The Indio Hills and the riverine drainage area along Interstate 10. These flood flows pass through the existing residential development via three flood control channels. A two-dimensional flood routing model (FLO-2D) was applied to study the progression of a flood flow in the interim floodplain area. Model results were analyzed to depict contour plots of the maximum flow depths in the interim floodplain for two discharge conditions that were simulated. The peak discharges entering the project area were estimated from the model results. Two flood control channels are proposed to accept these floodwaters and carry them out of the project area. The U.S. Army Corps of Engineers' River Analysis System (HEC-RAS) computer program was used to compute water surface profiles in the two flood control channels for the peak discharges. A sediment transport analysis was also conducted for one of the channels using the U.S. Army Corps of Engineers HEC-6 model. Model results showed that sediment passes through the system well and is not expected to interfere with the function of the flood control channel. Maintenance measures will be in place in order to clean the sediment out of the channel after a large flood event. The design water surface elevations in the flood control channel are based on the greater of either the HEC-RAS calculations using bulked flow, or the HEC-6 computed maximum water surface elevation using the unbulked flow. All sections have adequate freeboard between the design water surface elevation and the top of pad for the design flood event.

In a previous investigation, five maximum annual winter period daily depths of precipitation series from gaging stations on the U.S. Department of Energy's Nevada Test Site were examined from the viewpoint of the effects of El Nino - La Nina events on the series. This analysis demonstrated at the five precipitation gages considered, with periods of record ranging from 33 to 45 years, that there were actually two data series; one series associated with El Nino periods and a second series with La Nina events and neutral periods. That is, the precipitation data series contained a mixed population. This has critical implications from both the viewpoints of flood hazard identification and mitigation when rainfall-runoff modeling is used and environmental restoration. In this paper, annual maximum (winter and summer) depths of precipitation are analyzed for five long-term gaging stations in the Phoenix, AZ area.

The central message that ASFPM is trying to communicate is that we continue to cause flood damages and these flood damages have not been communicated effectively. This is in part due to the floodplain management community as a whole spending too much time debating issues of individual standards while not stepping back and evaluating the broad impact of the range of management approaches throughout the watershed. Current management systems to reduce flood losses are costly and often allow development that fails to evaluate or mitigate adverse impacts on other properties, both now and in the future. No Adverse Impact is an approach that will lead to reduced flood losses throughout the nation while promoting and rewarding strong management and mitigation actions at the local level.

Flood damage functions are necessary to ensure comprehensive risk management. This study attempts to establish a residential flood damage function and explores residents living in the Keelung basin, where flood disasters occur frequently in Taiwan. Ordinary least squares (OLS) method is used to construct a flood damage function. Analytical results indicate that flood depth, is the significant variable, but the residual is non-stationary with spatial. The Geographically Weighted Regression (GWR) model is applied to modify the traditional regression model, which cannot capture spatial variations, and to solve the spatial non-stationary. Analytical results demonstrate significant spatial variation in the local parameter estimates for the variable flood depth and intercept. Therefore, a dummy variable, Zone, is added to the OLS model. The R-square value is found to increase from 0.15 to 0.24, and the residual is spatially stationary. In conclusion, the residential flood damage is determined by flood depth and zone, and the GWR model not only captures the spatial variations of the affecting factors, but also helps to discover the explanatory variable to modify the traditional regression model.

In 2004, an agricultural to urban land-cover gradient approach was used in a study of habitat and geomorphic responses to urbanization for 30 streams in Milwaukee and Green Bay, Wisconsin. Multiple scales of land-cover and landscape (reflecting glacial geologic setting) characteristics were compared to reach-scale habitat/geomorphic characteristics using correlation analysis. Urban streams had enlarged channels and more bank erosion than agricultural streams. However, geomorphic channel units and substrate characteristics mainly were related to subtle variations in reach slope. Hydrologic metrics, including flashiness, were of limited use for explaining habitat variations or geomorphic response. Bank stabilization, and historical channel modifications potentially confounded relations, emphasizing the need to recognize historical bank and channel stabilizations for site selection and habitat assessment. Studies of geomorphic processes and responses to the complex interaction of changes in watershed runoff and sediment with local geologic and anthropogenic controls would be needed to adequately predict habitat degradation associated with urbanization.

Current characterization of urban watersheds and the modifications caused to natural areas once developed are mostly based on the descriptions of changes in the land-use and how these changes affect the processes of storage, infiltration and runoff generation. The objective of this article is to show how this characterization can be improved by also considering morphological and topological features of urban catchments and how they differ from the ones observed in natural basins. After introducing the study of morphologic and topologic features in watersheds, the paper exemplifies some of the changes caused to these features in natural catchments by urban development. Results shows major alterations to the morphology of basins and their drainage systems that need to be considered to better understand the hydrologic response of anthropogenic basins, and to improve the modeling and design of sub-urban and urban areas. Finally, a series of advantages of this approach are discussed.

Development in sensitive watersheds continues to pose environmental problems for receiving waters. Materials, such as galvanized metal, concrete, asphalt and wood products, may release pollutants into urban runoff and snowmelt; however, the long term effect of commonly-used roofing materials on the environment has not been quantified. This lack of long-term testing poses a particular problem because roofing is ubiquitous in the urban environment and covers a comparatively large amount of the surface area available to generate runoff. Laboratory testing on common roofing materials indicated that the potential for release (primarily nutrients, hydrocarbons, pesticides, and metals) is substantial. Further testing on painted, galvanized roofing tiles that were exposed to the Pennsylvania climate for 60+ years indicated that material continued to be released from these panels — indicating a deeper reservoir than simply the loss of a sacrificial surface coating. The ongoing research project involves testing a variety of construction materials (roofing materials, treated and untreated woods) to determine their long-term pollutant release after typical installation and exposure to the weather. The goal is to develop a better understanding of how the aging and exposure processes will impact the release over time. Understanding the `release vs. time' of a pollutant from a material will be crucial for translating the laboratory results to the actual environment and to developing predictive models for evaluating new materials for their pollutant potential. To accomplish this, at PSH and UAB, intact sections of these materials were installed on outdoor frames in areas not subject to canopy cover. Initial testing showed that nutrient concentrations were elevated early in the materials' life, as were the metals. Now, over one year of installation and testing has occurred. For many of the pollutants, the concentrations have leveled off to much lower concentrations. For most pollutants, especially nutrients, periodic spikes in runoff concentrations can be correlated to noticeable degradation in the material itself. Preliminary metals results show that lead concentrations are just above the detection limit, while copper releases are much greater for many materials. Runoff concentrations of copper for asphalt shingles and the two treated wood panels exceeded 500 μg/L during the first two weeks of exposure (with multiple storms during that period to wash off any surface coating).

Stormwater runoff from the paved surface of commercial ports has been investigated at the plot scale within the port industries of the Liguria Region (Italy). In particular the paper focuses on the characterization of the storm runoff quality in the container terminal and the tourism terminal sites. Both experimental catchment has been monitored for hydrology, chemistry and particulate loads. General water quality parameters (TSS, COD, pH, HC_tot, conductivity) as well as dissolved and particulate metals have been examined. Stormwater quality data collected confirm that pollutants EMC values are significantly higher than those observed in other urban land use sites. At both sites a mass-limited first flush phenomenon is generally observed for TSS while dissolved metals reveal a tendency to a linear response with respect to runoff volume. Particular attention is given to the partitioning of metals, which has direct implications on stormwater treatment BMPs for particle separation or treatment of the soluble fraction. The trend in non-equilibrium heavy metal partitioning has been analysed using the dissolved metal fraction f_d and the partition coefficient K_d.

The practice and study of watershed management has a long, rich history. Yet, the potential contributions of this field appear to be substantially constrained in many situations. Watershed management provides a powerful and integrated systems-based theoretical framework to address water resource management issues. It provides a mechanism to build consensual, win-win solutions to water resource problems, bridge science and policy, integrate solutions across agencies, jurisdictions and disciplines. For all its strengths, though, it seems oddly rare that comprehensive, sustainable watershed management efforts are the anomaly instead of the norm. An assessment of opportunities and constraints to more sustainable watershed management, from both the public and private perspective, identifies education, economics and collaborative planning as both obstacles and opportunities for complete watershed management.

Stormwater which is resident in surface water sources immediately after a rain event can be used to supplement water supplies. Within this paper, advocated is the use of detained stormwater in storage for a temporary period of time and used as a source for non potable uses. This can be done from storage areas such as stormwater ponds, underground vaults, and cisterns. The benefits are numerous, but perhaps for most situations, the greatest are lower cost for irrigation as stormwater replaces potable waters and a reduction in mass loadings to waters of the Nation, thus helping to meet TMDL standards. It is also an option for urban areas where stormwater management is sometimes not practical or even attainable with present technologies. Best Management Practices (BMPs) are discussed as they relate to stormwater use. Also, treatment trains of BMPs are encouraged to help design for higher levels of mass removal.

The goal of controlling peak flow rates at individual sites to pre-developed levels can be met using detention basins for design storms from 2- to 100-year return periods. However control of peak storm runoff flows along receiving streams by multiple detention basins operating simultaneously within larger urban catchments are much more difficult to achieve. The latter topic was studied in the past by several investigators, but the findings were very limited in scope and were focused primarily on larger runoff events such as the 10-year to 100-year flows. At the same time, there is evidence that stream geometry, water quality and aquatic habitat are impacted significantly whether this type of detention is used, or not, as areas urbanize. The profound hydrologic and geomorphic changes caused by urbanization require more robust control of the frequently occurring, smaller, runoff events. In response to this, different approaches toward designing stormwater detention were investigated and modeled by the authors. This testing was first done using design storm protocols employed by the Urban Drainage & Flood Control District for the Denver area of Colorado and then followed up using the EPA SWMM 5.0 model calibrated to 15-years of recorded 5-minute rainfall (5 gages) and runoff (2 gages) data for a 3.1 square mile watershed. This paper presents the findings most applicable for the Denver region and other locations having similar precipitation patterns; however, the underlying principles used to develop this concept can be used to develop design protocols for other hydrologic regions of the USA and other countries. This approach for the sizing of detention basins has been labeled by the authors as full-spectrum detention and was based on the following: 1) The first stage of a two-stage full-spectrum detention (FSD) basin captures approximately the volume equal to 1.1 times the excess urban runoff volume (EURV). EUVR is the difference in volumes between urbanized and predevelopment land use conditions, 2) This EURV is then released over an extended period of time (72 hours in the final version), and 3) The upper stage is sized to capture the larger events to control the peak flow rates to predevelopment for the 10- 25-, 50- or 100-year or storm (100-year event in the case tested). This paper describes how this concept was developed and evaluated and that it shows promise in providing simple on-site detention design protocols that reasonably controls stormwater peak flow rates not only at individual sites but also along receiving waters when multiples of similarly designed on-site detention basins are used in larger watersheds. The controls provided are quite robust for a very broad spectrum of runoff events; from very small to very large.

The development and application of multifunctional engineered permeable pavement, for example cementitious permeable pavement (CPP), can fulfill requirements for relatively smooth load-transmitting surfaces while serving as a more environmentally-conscious infrastructure material that functions to restore the in-situ hydrology and as a passive unit operation and process for treatment. This construction material technology reduces runoff, filters and treats infiltrating runoff pollution and reduces thermal pollution and temperature; while providing the load carrying capacity of conventional pavement. Cementitious permeable pavement (CPP) for rainfall-runoff has the potential to provide in-situ quantity and quality control. Two specific aspects of this control that have been the subject of significant interest and discussion are filtration and clogging. This study investigated filtration and clogging of CPP subject to stormwater particle loadings for a sandy-silt particle size gradation. The CPP was one component of an LID partial exfiltration reactor (PER) system that was designed as a pre-treatment and primary treatment interface for down-gradient secondary adsorptive-filtration in the PER. The CPP was installed and utilized at a source area loading site in urban Cincinnati, OH site subject to direct runoff loadings. Each CPP specimens had similar pore size distributions, with an effective porosity of greater than 20%, and total porosity that exceeded 25%. Results indicated total removal efficiencies exceeded 80%, and ranged from nearly complete removal for sediment-size particles to a 50% removal for suspended particles. Turbidity reductions were significant and effluent turbidity was generally reduced to below 10 NTU, with the reduction following a first-order exponential decline. Filtration by CPP included surficial straining and deep-bed filtration with the associated reduction of initial hydraulic conductivity for a fixed hydraulic gradient. For all loading conditions the initial hydraulic conductivity was reduced from that of clean coarse sand to fine silt. The hydraulic conductivity profiles illustrated a first-order exponential decline. Any unit operation or BMP that is effective requires regular maintenance; and CPP is no different. The high degree of effectiveness exhibited by CPP is a clear indication that the filtration capacity of CPP must be maintained. In-situ CPP cleaning methods illustrate that greater than 90% of the initial hydraulic conductivity can be restored after CPP clogging, respectively. Results provide a quantitative assessment of filtration, clogging and hydraulic restoration of CPP loaded by rainfall-runoff. CPP particle removal efficiency illustrated a dependence on loading concentration on a mass basis, as would be expected since higher mass concentrations were generally a result of more mass towards the coarser particle fractions.

Bioretention basins have the potential to reduce the volume and velocity of stormwater flows and remove some stormwater contaminants. However, because they are a function of soil or sand-based media mixes, their design may vary by geographical region. Laboratory soil column experiments were conducted to determine the mix media and proportions that would likely perform well in field-scale basins in the Charlotte-Mecklenburg region of North Carolina. Specifically, the study focused on the contaminant removal capacity of native piedmont soils (red clay, yellow clay, and top soil, compost, and sand) in media mixes. Further feasibility of substituting some inexpensive waste materials (crushed brick, ground glass, and tire chips) for sand and gravel was assessed with respect to contaminant removal. The results showed clay soils that typify the Piedmont region are fair performers with respect to pollutant removal; however, infiltration rates were slow and could lead to potential long-term operation and maintenance problems. Commercial topsoil performed best when amended with sand. Lower nutrient removal was noted in columns containing compost. Overall, the alternative materials performed comparably to control columns containing standard construction sand and gravel.

Green roofing is a best management practice for urban areas where land for traditional stormwater practices is unavailable. However, it is unknown how effective they are at treating stormwater. The two primary research objectives are the following: 1. To develop an effective media for green roofs that will improve roof runoff quality while maintaining the known water retention benefits of green roofs, and 2. To demonstrate that green roofing will generate lesser pollutant loadings into urban runoff than traditional roofing materials. In Phase I (currently ongoing), several green roof media (formulated from commonly-used expanded minerals, stormwater filter media, and organic matter) are being evaluated for their abilities to retain the pollutants from a synthetic acid rain. The samples are being analyzed for metals, nutrients, pH, and conductivity. The hypothesis is that one media will be "better" at pollutant removal and permanent retention. In Phase II, once the optimized media has been selected, it will be field-tested on a green roof. The water quality of the runoff from the green roof will be compared with the runoff quality from a traditional roof. Field testing will address two objectives: 1. The media is capable of supporting the green roof plants, and 2. The anticipated removals (including water retention) are actually seen in the field. Phase I results on the mineral portion of the future media mix demonstrates all media were able to neutralize the acid rain. Comparing the media for pollutant removal and retention, the expanded shale was best able to retain phosphorus, ammonia, and metals from the synthetic acid rain. Phase I results on the mineral and additive combinations show the expanded shale and granulated activated carbon mix to be the most effective at pollutant removal and retention.

Bioretention systems are stormwater treatment devices installed to remove both dissolved and particulate pollutants. As stormwater percolates through the bioretention system, dissolved pollutants are removed from solution by chemical and biological processes. In our study, 20 bioretention mesocosms (10 with loamy sand and 10 with sandy loam, half with and half without vegetation) were used to investigate hydraulic behavior and dissolved nutrient retention. The mesocosms were dosed with 120L to 160L synthetic stormwater comprising 0.8 mg-l^–1 TP and 4.8 mg-l^–1 TN over 3h to 5h. The infiltration and percolation rates in the sand was rapid (>15 cm-h^–1), while rates in the loam were much less (2–3 cm-h^–1). Retention time in the sand was 1.5h while that in the loam was well over 10h. The effluent was collected in 150L containers. Composite samples were taken after 24h in the sand and 48h in the loam. Average TP retention in the vegetated loam mesocosms was over 90%, compared to 75% in non-vegetated (barren) mesocosms. TP retention in the sand was very high (average 90%), regardless of treatment. TN retention increased to 80% in the vegetated loam mesocosms from 43% in barren loam mesocosms. TN retention in the sand was less overall, with retention increasing to 41% in the vegetated loam mesocosms from 26% in barren mesocosms. Increasing retention time in the sand mesocosms increased retention of nitrogen to 61%, nearly a 50% increase in retention performance. Nutrient retention persisted even under very high nutrient loads. While the loam is initially a less effective media by itself, the presence of vegetation substantially improves TP and TN retention. TN retention performance is improved by increasing in retention time.

Swales are "engineered vegetated ditches" that provide stable routing for stormwater runoff and a low-cost drainage option for highways, farms, industrial sites, and commercial areas. It is reported in the literature that swales mitigate runoff-carried pollutants, reduce runoff volume, and reduce peak stormwater runoff rate that can damage low-order streams and transfer pollutant loads carried in the runoff to receiving waters. EPA recognizes the reported capabilities of swales to reduce the environmental footprint while meeting the practical need to manage stormwater runoff. Further research, however, is needed to provide a more complete understanding of swales operations. This paper introduces EPA's swale research strategy, lessons learned during swale construction, and initial results of media and water balance trials. By developing a more complete understanding of the functions and capabilities of swales, it is hoped that the user community will be equipped to design and construct swales that efficiently reduce pollutant loading and protect receiving waters. Outcomes of this research are expected to help managers and regulators meet designated uses and goals outlined in the Clean Water Act, and maintain a continuing supply of high-quality water for human and aquatic life and economic growth.

Vegetated channels are commonly used along roadsides, in residential neighborhoods, and in commercial developments for both conveying water and achieving water quality benefits. In some cases, the integrity of the channels depends solely on the success of vegetative establishment by itself, while in other cases, the vegetation is established with the aid of turf reinforcing mats (TRMs). However, the experience with vegetative channels varies with climate and soil type, to name two major site-specific variables. In addition, there is an impressive array of TRMs available with little objective guidance on how to incorporate TRMs in the design of vegetated channels. The authors have completed preparation of the 3^rd Edition of the Federal Highway Administration's Hydraulic Engineering Circular (HEC) number 15 "Design of Roadside Channels with Flexible Linings." This paper describes new guidance for incorporating site-specific soil and vegetation characteristics into the design of a stable channel. It also summarizes a model for the interaction between vegetation and TRMs as well as the data required from the manufacturer for design following specific testing protocols. With this new national guidance, successful designs may be implemented considering local conditions and material availability.

Rain gardens are an effective technique to help integrate stormwater management features into the landscape, and take something that is typically viewed as a problem (stormwater runoff) and turn it into an asset (beautiful landscaping). Rain gardens are not just for residential yards. They have been successfully designed to catch runoff from buildings, parking lots, driveways, and roads. Rain gardens are used to capture stormwater runoff near the point of generation and help mitigate the adverse hydrologic impacts of urban development. They slow runoff, reduce runoff volume by infiltrating stormwater into the ground, and filter pollutants in the process. Although rain gardens and similar Low Impact Development (LID) techniques are generally considered for their water quality benefits, studies in other communities are documenting hydrologic benefits from these techniques as well. Thus, they can also be important tools to help prevent the stream degradation that is becoming all too common in our urbanizing areas. This presentation will cover the science and design of rain gardens, demonstrate successful and attractive applications in municipal and commercial settings, and share success stories from communities that have documented their effectiveness.

The author's two-dimensional model for unsteady sediment discharge at a pond outlet was developed using the finite element method. The model simulates depth-averaged flow velocity in the pond and the depth-averaged suspended sediment moving from the pond inlet to the outlet. Modeling results can provide information regarding the depth-averaged suspended sediment distribution in the pond and the unsteady sediment discharge at the outlet. The model contains pond hydraulic parameters and sediment parameters. These parameters, however, need to be calibrated with field data. Once calibrated, the model can be verified as a useful sediment pond design tool that could benefit engineers who prepare erosion and sedimentation control plans for construction sites. A research group at Pennsylvania State University has performed numerous field experiments that have studied and continue to study sediment pond discharge. Some of the published data are adopted to calibrate the parameters. In this paper, the data quoted from Pennsylvania State University is designated as PSU data. Other data, quoted from a published Federal Highway Administration report, is designated as FHWA data. The FHWA data is used to develop a formula that defines the suspended sediment at the pond inlet after the influent sediment ceases within the pond inflow. This formula, defined and fitted to the FHWA data, is used for determining the boundary condition at the pond inlet for the model after the pond inflow approaches zero. The model calibration shows that more data is needed to quantify and detail the range for each parameter. Preliminary numerical values for the parameters have been found and can be important to engineers for sediment pond design. Using the field data without knowing the point of field sampling, however, could affect the model's calibration. Therefore, further investigation is required to define the range of numerical values that most accurately represent a pond's condition in the field.

The objective of this research was to estimate sediment yields and assess the relative effects of erosion and sediment control best management practices (BMPs) at natural gas well construction sites in north central Texas. Version 2 of the Revised Universal Soil Loss Equation (RUSLE2) was used to evaluate the efficiency of BMPs for different land surface conditions (slope and soil). Annual average and design storms sediment yields were evaluated. Annual average sediment yield estimates ranged from 12.11 to 134.50 tonnes per hectare when the sites were modeled without BMPs. When the sites were modeled with BMPs modeled yields were 50 to 93% less. A comparison of efficiency values for the various slope/soil type combinations revealed that both slope and soil type influenced the efficiencies of the BMPs. There were also differences in BMP efficiencies when sediment yields were modeled for 1, 2, 5, and 10-year design storms. This study demonstrates a practical approach to managing soil loss and understanding the importance of selecting appropriate site-specific BMPs for disturbed sites.

Background information, example computer model predictions, and field validation results are given for a new silt fence technology known as FAEST. Developed at Oklahoma State University, FAEST has the potential to dramatically improve sediment trapping efficiency at construction sites by eliminating typical failure mechanisms. In field studies, more than 90 percent of sediment was trapped. A model of the process has been developed, validated, and incorporated into the IDEAL watershed hydrology-water quality model. The model algorithms for the silt fence objects are based on fundamental theory and widely accepted empirical relationships. The user can predict the performance of FAEST for varying land conditions, terrain slopes, slopes along the fence, soil types, and rainfall patterns. The principal intended application of the model is for construction sites. Hydrographs, sedigraphs, and trapping efficiency are generated for flow through the fence along with predictions of effluent particle size distribution. Failure by means of overtopping of the fence can be identified. The model was validated using field studies conducted to evaluate the performance of the new silt fence technology.

The promulgation of the NPDES Phase II regulations since March 2003 has lead to an increase in the national awareness of construction site soil erosion and sediment control (SESC). In response to Phase II, many municipalities with small MS4s are entering the arena of regulating construction sites for SESC. Additionally, state environmental departments are increasing their presence, and authority, on more sites. However, as with many growing regulatory frameworks several issues have emerged. NPDES Phase I and II regulations have established a relatively well-defined baseline for SESC regulations. Many states and local governments have taken the opportunity to set more stringent regulations. As a result, owners, developers, and contractors across the nation are now required to be adequately prepared to face regulation from the local, state, and federal levels. However, inconsistencies exist in the level of implementation of the regulations between municipalities and at the federal, state, and local levels. The variability exists in the plan review stage and with the frequency and level of inspections during construction. Effluent limitation standards for Total Suspended Solids (TSS) for construction site discharges should be considered at the regional and/or local levels. The "visual inspections" that are currently being performed in many areas present a large amount of subjectivity from one inspector to the next. The development of effluent limitation standards should be based on the original goal of the Clean Water Act to create "fishable" and "swimmable" waters. Additionally, the development of numerical standards should be focused on restoring water quality rather than simply preserving the current state of water quality.

Fine-grained sediment accumulation in urban waterways, including lakes, rivers and detention basins is a common concern in urban areas. It is a common cause of waterway impairment in the United States as noted by the U.S. Environmental Protection Agency (USEPA). As more stormwater regulations are adopted across the nations that control both the quantity of water runoff and the quality of water runoff, man-made stormwater lakes have also accumulated large quantities of sediments that need to be removed. However, removing the sediment is often very difficult as the surrounding urban uses can make typical mechanical or hydraulic dredging operations very difficult or impossible to stage. With the widespread use of polymers, some techniques are emerging to remove fine-grained sediment hydraulically without the use of the large multiple acre confined disposal facilities commonly used for dewatering the dredge slurry. This paper describes some techniques that has been effectively used for rapidly dewatering dredge slurry in urban areas, for large sediment volumes, resulting in reusable or truckable solids.

State and Federal Regulations require many cities to develop Long Term Control Plans (LTCPs) to address combined sewer overflows (CSOs). A LTCP characterizes existing sewer system capacity and presents likely improvements required to meet receiving water quality standards. Integrating green infrastructure solutions for targeted areas in a watershed may provide cost effective CSO control opportunities with high public acceptance. The "green filter" approach identifies "green infrastructure" enhancement possibilities such as wetlands and wet ponds, bioretention cells, catch basin retrofits, and retention ponds to help manage and reduce stormwater that enters combined sewer systems. The green filter process utilizes geographic information system (GIS) software and remote sensing data to map topography, vegetation and soils, and open space. At its highest resolution, the green filter analysis can identify widespread micro-scale opportunities such green roofs, rain gardens, and bioretention cells. These opportunities are then evaluated based on catchment area, existing hydrology, existing and future conveyance systems, and overall cost to identify feasible conceptual designs. The final step is a site-by-site cost/benefit comparison between gray and green alternatives to determine locations where green opportunities can cost-effectively reduce combined sewer overflow frequency and volume. Based upon an evaluation of logical targeted locations, LTCPs may incorporate green infrastructure to reduce overflows and enhance the performance of traditional overflow control practices. The green infrastructure enhancements provide added benefits such as water quality treatment, public amenities, and wildlife habitat while helping meet the traditional overflow control goals of reducing frequency and volume of combined sewer overflows.

This paper describes the development of an optimal management model based on the modified Box Complex method of constrained optimization for an urban watershed impaired by point and non-point sources of pollution. The modified method is called the Shuffled Box Complex method of constrained optimization. This is achieved by linking the Shuffled Box Complex-based optimization model to a macro-level water quality simulation model for an urban watershed impaired due to low dissolved oxygen. The macro-level simulation model consists of a BOD load simulation model for the three streams of the Beargrass Creek watershed in Louisville, Kentucky. A nonlinear constrained optimization framework is thus formulated to allocate biochemical oxygen demand (BOD) loads in a way that satisfies economic as well as water quality considerations in the watershed. The optimal integrated watershed management model is used to evaluate various water quality management strategies leading to the optimal water quality management strategy for the watershed. A sensitivity analysis is performed to evaluate the performance of the management model with regard to varying dissolved oxygen standards enforced for the study area. The proposed optimization framework can serve as a useful management tool for watershed decision makers to formulate and evaluate different management strategies leading to effective capital improvement projects for the watershed. The cost of capital improvement projects in large urban watersheds can exceed 1.0 billion dollars and the use of such an optimization-simulation approach can result in significant savings by providing optimal solutions.

The general purpose of the Chino Creek Integrated Plan (CCIP) is to focus planning attention on the Chino Creek area of the Prado Basin in San Bernardino County, California. The Prado Basin lies behind the Prado Dam, the major flood control feature controlling the Santa Ana River and providing flood protection for the downstream highly urbanized County of Orange in southern California. The CCIP was undertaken by the Inland Empire Utilities Agency (IEUA) in partnership with Orange County Water District (OCWD), under a grant from the State Water Resources Control Board (SWRCB) and funding from OCWD and the City of Chino. CH2M HILL was retained by IEUA to develop the CCIP. The specific purpose of the CCIP is to identify those projects and measures that, when implemented, will result in improved water quality, flood control, habitat restoration, recreation, water conservation and public education within the context of the existing and future planned development of the area. The Study Area within the vicinity of the Santa Ana River watershed is shown in Figure 1. To determine the widest possible range of potential locations suitable for the various sustainable approaches, a Geographic Information System (GIS) was developed using the database of information collected during baseline data gathering. The data within each GIS layer were assigned numerical values and then overlain with other layers to score and rank locations for sustainable approaches based on such criteria as topographic suitability, creek channel geomorphic condition, or proximity to existing recreational trail systems. The results were then evaluated by the stakeholder forum and the optimum opportunities carried forward. GIS analyses were completed for streambank stabilization, stream restoration and both inline and offline treatment wetlands. In addition, the GIS tool proved useful in analyzing at the landscape level, the optimum location for habitat preservation and restoration.

Rainfall is a principal input in hydrologic and hydraulic computer simulations that form part of a master urban drainage planning study. The selected rainfall intensity, storm patterns and duration can affect simulated drainage performance. Rainfall input used in the Integrated Catchment Study (ICS) of Auckland City is presented, including reasoning, methods employed, and outputs generated. The NZ$23.5 million ICS was a four-year study to develop a comprehensive understanding of the Auckland Isthmus drainage systems and receiving environments. It was a computer modelling focused study to assist Auckland City Council and Metro Water Limited to develop robust understanding and solutions to address: (a) wet weather combined and wastewater overflows that can create short-term public health issues, (b) stormwater quality that can produce long-term environmental health issues, (c) habitable floor flooding that can produce economic loss and public health issues and (d) provision for growth, which can exacerbate drainage issues. To address these issues the ICS undertook: (1) long term time series rainfall simulations to depict typical drainage performance and (2) design storm simulations to identify extreme event performance. Long term time series consisted of five-minute interval rainfall for (i) current climate and (ii) most probable future (2050) climate scenarios. For current climate, historic and stochastic time series were used. Design storms were considered from a number of different sources; a 24-hour duration nested (alternating block) storm was adopted for use. This approach allowed problematic drainage and receiving environment issues to be identified and initial solutions developed in priority areas.

Statistical analysis of effluent event mean concentration (EMC) data is routinely performed to characterize the water quality performance of best management practice (BMP) and low impact development (LID) facilities for stormwater control. While the statistical procedures themselves are well documented, the relative usefulness of the various procedures is less obvious. This paper demonstrates some common graphical techniques applied to influent and effluent EMC data for a highway filter strip, with the intent to clarify their efficacy through their application to real data.

Particulate matter transported by the urban stormwater is a hetero-disperse mixture of particles. These particles are a potential concern not only because of the environmental and ecological issues related to particles, but also since many contaminants are bound to the surface of particles and can be transported through the aquatic environment. Recent studies have concluded that traditional analytical and semi-empirical methods are defensible approaches to modeling UOP (Unit Operations and Processes) behavior when combined with monitoring to stormwater loadings. However such methods are challenged under common non-ideal flow conditions and can misrepresent actual behavior subject to complex loadings. One alternative is application of the Navier-Stokes (N-S) equations; the fundamental equations of fluid flow. For complex flows, heterogeneous loadings and complex treatment geometries, solving these equations analytically is simply not a feasible task without simplifications that can compromise the value of such solutions. This has led to the development of various numerical schemes to solve the N-S equations. Advances in computational power have facilitated the use of the Finite Element Method (FEM) to investigate the multiphase dynamics. The CFD (Computational Fluid Dynamics) approach to examining and modeling the behavior of a stormwater UOP provides a complete picture of transport phenomena within the geometry of the UOP considered. An examination of particle treatment in stormwater is presented. This study examines the hydrodynamic and particulate response of a continuous deflective separator (screened hydrodynamic separator) with a set of algorithms incorporated into a CFD model. A hydrodynamic model was used to model flow and a Discrete Phase Model (DPM) determined particle trajectories and predict particle separation. Measured and modeled results indicate that for an influent suspended sediment concentration (SSC) of 200 mg/L, effluent SSC was 90 mg/L; and for an influent SSC of 0 mg/L a 50% sump depth of sediment yielded an effluent SSC of 100 mg/L. In order to ensure the validity of the model, CFD simulation results were calibrated and validated with monitored data and material balances to ensure results represented reality. The calibrated and validated CFD model demonstrated success in predicting particle separation behavior of the screened hydrodynamic separator.

This research quantifies variation in chemical constituent concentration in urban stormwater runoff within urban watersheds. The research studies statistical relationships between storm event characteristics and event mean concentration of selected chemically-conservative constituents in runoff originating from those events. The analysis uses factors including storm precipitation, antecedent dry period, antecedent precipitation, and storm rainfall intensity, and establishes statistical correlations for chemical constituent data in runoff from selected urban watersheds in California. The correlations succeed in explaining a substantial part of the variation in event mean concentration, though some variation originates from other factors as yet unidentified. Results demonstrated a substantial difference in explanatory models among waterbodies and among constituents. The variation in concentration was better explained by storm variables for some watersheds, as expected, particularly smaller watersheds with more homogeneous land use. Antecedent conditions were more important for some watersheds and some constituents, and storm conditions more important for others.

Three different laboratory methods have been used to quantify the amount of solids contained in the storm water samples. The three methods differ in the sub-sample preparation. In this study, the water samples of nine different particle concentrations over a range from 0 to 1000 mg/L and of seven different particle size distributions over a range from 0 to 1000 microns were prepared and analyzed for the solids concentrations using the three different analytical methods. It was found that the total suspended solids (TSS) concentration measured using EPA Method's sub-sample pouring procedure was well correlated with the suspended sediment concentration (SSC) measured using the ASTM Method's whole sample procedure. It was also found that the difference between the measured SSC and the measured TSS-EPA was well correlated with the particle size. The difference was larger as the particle size increased. A regression relationship between the TSS-SSC difference and the particle size was established. This regression relationship could be used to predict TSS-EPA from the reliably measured SSC if the particle size (or the equivalent particle size) is known.

The Environmental Technology Verification (ETV) Program was created to facilitate the deployment of innovative or improved environmental technologies through performance verification and dissemination of information. The program's goal is to further environmental protection by accelerating the acceptance and use of improved and more cost-effective technologies. ETV seeks to achieve this goal by providing high quality, peer-reviewed data on technology performance to those involved in the design, distribution, permitting, purchase, and use of environmental technologies. The program works in partnership with recognized standards and testing organizations; stakeholder groups, which consist of buyers, vendor organizations, and permitters; and with the full participation of individual technology developers. The program evaluates the performance of innovative technologies by developing test plans that are responsive to the needs of stakeholders, conducting field or laboratory tests (as appropriate), collecting and analyzing data, and preparing peer-reviewed reports. All evaluations are conducted in accordance with rigorous quality assurance protocols to ensure that data of known and adequate quality are generated and that the results are defensible. NSF International, in cooperation with EPA, operates the ETV Program's Water Quality Protection Center (WQPC), one of six technology centers in the ETV Program. The WQPC has evaluated the performance of eight stormwater treatment technologies designed to remove a variety of pollutants commonly found in stormwater runoff from roadways, parking lots and vehicle maintenance areas. The technologies are generally compatible with existing storm sewer inlets and provide treatment by gravity or inertial separation, or may contain a combination of screens and filter elements to trap pollutants. Field testing was conducted with full-scale commercial units, capturing runoff from 15 qualified storm events over a 15-month period using automated sampling equipment. Typical analyses included: total dissolved solids (TDS); total suspended solids (TSS); suspended sediment concentration (SSC); total and dissolved phosphorus; oil and grease (O&G); total petroleum hydrocarbons (TPH); chemical oxygen demand (COD); chloride; zinc, calcium, copper and magnesium, and; sand fractionation.

Stormwater gross solids are the coarse sediments, leaves, organic debris and human derived trash that are washed off during rain events, but are rarely quantified in stormwater studies. As part of ASCE/EWRI's Urban Water Research Resources Council, the Gross Solids Technical Committee is in the final stage of developing guidelines for measuring stormwater gross solids. The purpose of these guidelines is to standardize data collection procedures used in evaluating the removal of Gross Solids by Best Management Practices (BMPs) and to allow for direct comparison of field data from separate studies by using the same collection methodologies. This guideline does not address the pollutants in the water column since these methods have been well described elsewhere, but focuses on particles greater than 75 microns that are not measured using standard monitoring techniques. There are many variables to consider in monitoring gross pollutants. These include the purpose of the monitoring program, fiscal constraints, desired accuracy, parameters to be monitored, whether the BMPs traps Gross Solids in a wet, dry, or combined condition, and time constraints for completion of the program. Three program levels have been defined. Level 1 is basic collection of samples with a minimal amount of laboratory analysis. Level 2 starts with Level 1 and adds intensive techniques to separate litter, debris, and sediment, and uses laboratory analysis to quantify basic individual parameters of concern. Level 3 programs are research programs customized for specific goals. Note that the collection and analysis in each Level are minimum criteria, and additional techniques or parameters may be added as needed. These guidelines are preliminary and some of the recommendations have not been finalized. Also suggestions from other researchers in the field are encouraged.

As more manufactured stormwater treatment devices enter the market, stormwater managers are searching for effective and rapid methods for evaluating device performance. Many agencies require vendors to test full-scale versions of their devices under controlled conditions. The most common parameter used to document performance is suspended solids. Many pollutants attach to the solids and a solids simulant is relatively easy to generate. In addition, solids are comparatively easy and inexpensive to quantify. However, a controversy still exists in the professional community as to whether total suspended solids (TSS) or suspended sediment concentration (SSC) should be measured (several agencies require both but only use one to verify device performance). Second, agencies often specify different simulant mixtures for controlled tests. Third, sampling protocols, in particular sample preparation and filter nominal pore diameter, are not well-defined. Sample location in the flow stream can greatly affect the results, as can the procedure used for sample splitting. This paper focuses on the protocol developed and evaluated by two academic testing organizations during recent evaluations of two devices that were evaluated for solids removal performance. This protocol is repeatable and is not specific to solids testing, but allows for a single sample to be split into size fractions for subsequent particle-size and pollutant-association analysis.

New Jersey Department of Environmental Protection (NJDEP) is in the process of certifying removal efficiencies of total suspended solids (TSS) for various manufactured treatment devices (MTDs). Prior to the certification, the removal efficiencies are verified by New Jersey Corporation for Advanced Technology (NJCAT) under some specific laboratory testing and field monitoring conditions. However, the TSS removal performance is expected to vary with operating flow rates, unit sizes, and laboratory or field evaluation techniques. Several technical issues related to the uniform certification have been researched. Among them are difference between TSS and suspended sediment concentration (SSC), extrapolation of operating flow rates, unit size scaling, impacts of particle size and influent concentration, and possibility of bottom sediment re-suspension. NJDEP has made amendments to the TARP field monitoring protocol to further constrain the field monitoring conditions and to additionally require the particle size measurements and the sediment re-suspension tests. Beyond the TSS removal performance, unit-sizing methodology and device maintenance requirements may need to be verified and certified.

A wide variety of best management practices (BMPs) are available for controlling urban stormwater quantity and quality. In-situ controls and low impact development (LID) methods and materials provide a distributed network of onsite stormwater control. When trying to implement onsite controls in an urban environment, runoff volume control must be performed within spatial constraints and it can be difficult to determine the net control of decentralized BMPs within a watershed. The paper illustrates a tool that quantifies the net effect of onsite control methods in subcatchments ranging from 0.01 to 7 acres. The methodology presented herein steps through transforming data into a usable geographic database, transferring data from the geo-database to a hydraulic/hydrologic modeling program, and evaluating BMP performance by manipulating functional land unit parameters. Results indicate that, under such a disaggregated examination, BMP functions are ubiquitous only varying in degree, serving as control areas as well as sources of runoff in what can be a long chain of storage-infiltration-runoff steps. These disaggregated BMP functions can be represented explicitly by simulating a parcel or catchment at the functional unit scale, capturing the spatial reality of the catchment while still providing an approach to modeling the net control of a larger watershed.

Accuracy of simulated flows resulting from applying transferred rainfall-runoff parameters is evaluated with observed flows from Tinley Creek watershed (28.67 km²) in northeastern Illinois. Two previously calibrated rainfall-runoff parameter sets (Current and CTE) for the Hydrological Simulation Program-FORTRAN (HSPF) model developed in a separate watershed, are applied in the evaluation. In the watershed model development, watershed land-use data are obtained from digitizing the 2005 enhanced aerial photos according to the 11 land-cover categories used in the previous studies. The evaluation simulation period was from October 1996 to September 2003. An analysis of the percentage of effective impervious area is also reported. Rainfall-runoff correlation, runoff coefficients, and simulated sub-surface runoff volumes, in addition to surface runoff volumes are examined. Results indicate that the Current parameter set estimated higher evapotranspiration than the CTE parameter set, and therefore lower surface-runoff volumes were simulated. The Current parameter set simulated less infiltration and interflows, but more groundwater storage and groundwater runoffs than the CTE parameter set. Comparison of the ratio of simulated to recorded flow records (S/R ratio) indicates that the CTE parameter set is more suitable than the Current parameter set for simulating flows in this watershed. The overall S/R ratio for Tinley Creek is 0.85 for the simulation period.

Reproducing moisture retention behavior of the upper and lower vadose zone in shallow water table settings provides unique challenges for the integrated (combined surface and groundwater) hydrological models. The theory and behavior of one model, the Integrated Hydrological Model (IHM) is examined through comparisons with collected data at a study site in West-Central Florida. The objectives of this exploration were to (1) test a model of the vertical processes controlling water table behavior, evapotranspiration, ET distribution flux and infiltration, (2) investigate the sensitivity of model parameters on model vs. observed vertical behavior, and (3) offer recommendations for improvements and parameterization for regional model application. Rigorous testing was done to better understand the robustness and/or limitations of the methodology of the IHM for upper and lower vadose zones. The results are also generally applicable and useful to the upper zone and lower zone conceptualization and parameterization of stand-alone HSPF applications and perhaps other surface water models. Simulation results indicate IHM is capable of providing reasonable predictions of infiltration, depth to water table elevations response, evapotranspiration distributions from the upper soil, lower soil and water table while incorporating field scale variability of soil and land cover properties.

This paper addresses the nature of contamination that may enter surface water bodies from the subsurface, with particular consideration to effluent discharges of nutrients from treated wastewater disposal systems. The pathways and transport mechanisms are addressed by considering the transport of phosphorous and other constituents from a sewage-contaminated aquifer into Ashumet Pond, a kettle pond located adjacent to the Massachusetts Military Reservation (MMR) in Cape Cod, MA. For this paper, some previous ground-water data are analyzed and additional surface-water and ground-water samples are collected to characterize the nature of the exchange processes. As such, these results are intended to complement previous analyses being completed by the USGS. Ground-water samples were collected during the summer months of 2005 from multi-level samplers (MLSs) located adjacent to the pond. Results for ground-water samples were found to match the previous results well, confirming that significant loads of phosphorous enter the pond from ground-water. Results also indicated that the phosphorous transport might be affected by phosphorous associated with solids. Trends in surface-water samples collected from a number of locations at varying distances from the banks of the pond revealed that phosphorous distributions may be affected by presence of a geochemical barrier and also by variability of ground-water entering the pond. Additional results, including chlorophyll-a analyses and in vivo chlorophyll-a estimates obtained with fluorometer, also provided insight into the nature of phosphorous discharge in the vicinity of the geochemical barrier. The results illustrate the near-shore trends in nutrient discharge from ground-water into surface-water, and also illustrate the importance of the pathways that nutrients follow as they enter a lake.

Lake Burragorang in South-West Sydney, holding 2.1 billion litres of water, is the principal source of drinking water supply for 4.5 million Sydney residents. The Wollondilly, Nattai, Kowmung and Coxs are the four major tributaries that provide approximately 83% of total inflow into the lake. Each of these tributaries has catchments with substantially different geology and hence the sediment loads contributed by each of these rivers have their own characteristics. As a part of the water quality analysis within lake Burragorang, sediment grabs were extracted from the lake bottom (from pre-selected locations) with a view to determine spatial variation of sediment characteristics across the lake. A total of eleven sites were chosen for sequential extraction of sediment grabs. Samples were analysed to determine distribution and speciation of 14 selected heavy metals (from 11 sites) in bed sediments. The results were correlated with the geological and human histories of the local catchments and reservoir operations. A consistent general trend in metal concentration variation was observed. Some sites showed lower concentrations of metals than the background level whereas other sites indicated metal concentrations to be far higher than the background level. These were found to be related to previous mining activities. In general, no significant spatial variations were observed in the speciation trends.

Global climate change will have many effects on various aspects of our lives, and in particular on watershed issues such as drought, flooding, sediment behavior, and pollution runoff. This paper will summarize these pertinent issues and relate the current state of the knowledge in this field through a detailed literature review.

This study examines the relationship between changes in precipitation and temperature and the properties of low streamflow to estimate the potential impact of climate change on design-period low flows and associated Total Maximum Daily Loads (TMDLs) of primary pollutants. Stepwise linear regression is used for predicting the future low-flow statistic Q_7,10 using the physiographic and climatic characteristics of 160 watersheds in the Mid-Atlantic region of the United States. Based on four general circulation models' (GCMs') climate predictions of future increases in temperature and variable changes in precipitation, model results show a decrease in the Q_7,10 over the 21st century. Using Latin Hypercube sampling of parameter estimates, the fractional change in low flow and the resulting change in TMDL of a point-source primary pollutant are estimated for GCM climate predictions; for most predictions, a future reduction in contaminant load will be necessary to meet current water quality standards. Once GCM predictions improve, incorporating future climate scenarios in TMDL planning may preserve minimum water quality standards while avoiding a TMDL reallocation in the future.

In California Climate warming is expected to shift the runoff peak from spring to winter from a reduction in snowpack. For high-elevation hydropower plants, this shift can have important effects on power generation and its economic value. With over 150 hydropower plants in California, estimation of climate warming effects by conventional simulation or optimization would be tedious and expensive. Two approaches are suggested to estimate climate warming effects on high-elevation hydropower in California. The first (No-Storage) approach neglects available storage capacity and produces an upper bound estimate of lost generation and hydropower revenues from climate warming. The second (No-Spill) approach estimates the available energy storage capacity assuming that existing capacity is enough to avoid spill from high-elevation reservoirs with historical mean flows, providing a lower bound estimate of generation and economic losses. The generation changes in dry and wet climate warming scenarios at different elevation ranges are simulated in aggregate for several climate change scenarios and compared to the historic generation.

The current techniques for flood frequency analysis presented in Bulletin 17B assume annual maximum floods are stationary, meaning that the distribution of flood flows is not significantly affected by climatic trends or long-term cycles (i.e. decadal variations). Observed trends in stream flows raise concern as to whether or not this assumption is valid. This paper considers how the Bulletin 17B framework might be modified to account for nonstationarity in flood records due to climate variability. In order to improve estimates/forecasts obtained using the LP3 model, the effects of climate variability may be incorporated into updated estimates of the mean, standard deviation, and perhaps the skew by regressing the LP3 parameters on climatic indices describing the Pacific Decadal Oscillation and Northern Atlantic Oscillation. The effects of climatic cycles occurring over a shorter time frame, such as El Niño, are averaged into estimates made using the procedures of Bulletin 17B. However, the effects of El Niño are likely to affect the magnitude of annual maximum stream flows, and thus would impact flood risk in a given year. El Niño effects are incorporated into forecasts by regressing the LP3 parameters on sea surface temperatures.

Climate in any region is the result of both short- and long-term phenomena interacting at local, regional and global scales. In South Florida where major changes to the water resources infrastructure are being contemplated for facilitating the restoration of large-scale ecosystems such as the Kissimmee River Basin and the Everglades, consideration of climate variability on scales ranging from intra-seasonal to multi-decadal is extremely important in both water resources planning and regional operations. Correlations of hydro-climatology of South Florida to such global phenomena as El Nino-Southern Oscillation (ENSO) and Atlantic Multi-Decadal Oscillation (AMO) have been investigated extensively. This paper provides an overview of the climatic indicators and the teleconnections that are significant for south Florida. In particular, the application of the research to develop regulation schedules for the operation of Lake Okeechobee as well as the real-time implementation of rules based on climate outlook are discussed. The use of computer modeling as a tool for the design of operating rules as well as real-time operations is also included.

The evaluation of long-term drought variability was investigated for the Colorado River basin using instrumental and reconstructed streamflow data. Streamflow data was reconstructed for the past 500 years in the Colorado River Basin using Partial Least Squares Regression (PLSR). The occurrence of past drought events is also presented for 17 streamflow stations in the basin. Results indicated that the 1500's through the 1800's had more droughts than the 1900's. In addition, the worst drought years were in the late 1500's.

The application of climate-based outlooks for operational planning in south Florida is an ongoing reality. Currently, the operational schedule for Lake Okeechobee considers the expected seasonal and multi-seasonal net inflow based on Croley's method and an in-house empirical method, both of which rely on the Climate Prediction Center's seasonal climate outlooks, and on sub-sampling of historically-observed inflows under analog historical climatologic conditions. A refined method which incorporates antecedent conditions into the inflow forecast is also discussed. The purpose of this paper is to compare the performance of various methods for calculating net inflow outlooks for Lake Okeechobee for the period 1995 through 2005 against actual inflows.

Flood is one of the most important natural disasters which causes extensive loss of life and properties every year around the world. By forecasting the hydrograph of probable floods in each year, their damages could be reduced by implementing plans, decisions, and actions. Before flood forecasting, it is necessary to forecast rainfalls. By forecasting rainfall, the amount of runoff can be estimated. So it can be determined whether a severe flood would happen or not. The simulated flood hydrograph is affected by uncertainties in rainfall forecasting that must be considered when flood prevention plans are developed. In this study, a long lead flood forecasting model is developed, considering the uncertainties in forecasting. This model uses long lead predicted rainfalls on a daily basis. The predicted rainfalls must be disaggregated to smaller time and space spans (say 6 hours) in order to be used in rainfall-runoff models. So, predicted rainfalls by a GCM (General Circulation Model) have been downscaled using a regression based statistical method. Then HEC-HMS software has been used to develop a rainfall-runoff model of the basin. Using downscaled predicted rainfalls and the rainfall-runoff model of the basin, the predicted flood hydrograph is determined. The effect of uncertainties in rainfall forecasting has been considered in flood forecasting. In daily precipitation, uncertainties have been assessed by comparing means and variances of precipitation, monthly mean dry and wet spells lengths and their confidence intervals and cumulative frequency distributions (CDFs) of predicted floods. The proposed model for flood forecasting has been applied to the Kajoo River located in South Baloochestan region, in the south-eastern Iran.

In this paper, an innovative method for clustering of climate signals is developedusing Genetic Algorithm (GA). In this model, the relation of the signals with thevariations of another climatic variable is considered in clustering algorithm. In thecase study, the model is used for clustering the Sea Surface Temperature (SST) datain Omman Sea, Arabian Sea, and Indian Ocean considering the precipitationvariations in Sistan-Balouchestan Province in Southeast of Iran. For this purpose, theprecipitation data is classified to the three categories of below normal, normal, andabove normal and the fitness function of the GA model is formulated to minimize thevariance of the precipitation for each selected cluster. The results show that the modelcan be effectively used for prediction of low and high precipitation seasons in thestudy area using the SST variations in the defined clusters.

This study examined changes in the seasonal pattern of soil water content under a tall grass prairie in central Oklahoma as a result of the 2005–2006 drought. The seasonal pattern of soil water content in the top 50 cm of the soil profile was minimally impacted by the drought, as this portion of the profile was recharged by sporadic precipitation events. However, no moisture reached the soil profile below 50 cm after June 2005, as all precipitation was intercepted and held by the top soil layer and rapidly consumed by evapotranspiration. The dry conditions in the lower soil profile have led to an agricultural drought in 2006 that may persist for some period after the precipitation returns to normal levels and until the lower portion of the soil profile is recharged to provide a moisture pool that prairie grasses can tap during the summer growing season.

In part I of this study the strong teleconnections between large-scale atmospheric circulation patterns and the peak of snowpack measured by snow water equivalent (SWE) in Washington State were established by a linear regression model. However, the underlying dynamics of snowpack for each snow telemetry (SNOTEL) site are unknown. The statistically significant correlations between the peaks of snowpack and large-scale climate indices do not necessarily imply linear relationships among them. Moreover, these correlations do not imply a deterministic or stochastic dynamic process underlying snowpack SWE data. To better understand the complexity of snowpack dynamics in Washington State, a technique developed from nonlinear time series analysis and dynamic theory called surrogate data testing was used to investigate the complexity of snowpack dynamics in terms of determinism vs. randomness. Some relatively new concepts, such as embedding dimensions, time delay, phase re-construction, correlation dimensions and prediction errors are introduced to hydrologists and water managers to characterize the complexity and predictability of the snowpack at specified sites.

The consequences of climate change will affect both natural systems and human populations. Adaptation policies that provide mitigation against these effects require the collaboration of natural and socio-economic sciences to assess future risks of climate change. Future impacts and the vulnerability of the impacted system are used to perform risk assessments allowing decision-makers to select optimal adaptation choices given available knowledge. Under climate change, however, future risk assessments are based on a number of possible climate scenarios. This multiplicity results in more than one assessment of risk with large uncertainty bounds. Present applications of risk assessment for climate change adaptation have taken two main approaches. The main difference between these approaches is in the presentation of the final risk either as cumulative probability distributions of threshold exceedance or as a number of risk assessments assigned to different plausible futures. Different adaptation scenarios or policies are then evaluated in terms of their effectiveness in reducing risk. This paper presents an analysis of applications of both approaches of risk assessment from recent literature for climatic effects such as sea-level rise. The analysis provides an evaluation of the strengths and weaknesses of present climate change risk assessment methods in terms of providing useful information to support decision-making at relevant spatial and temporal scales, and the ability of each method to direct policy-development by providing the best representation of future uncertainties given policy objectives. This analysis sheds light on the utility of climate change risk assessment methods as a function of information availability and policy scope, thereby providing the necessary factors that decision-makers should consider when a choosing an approach for adaptation policy development.

Europe is immersed in an age in which the need to improve water management and planning models has become increasingly evident. This phenomenon is even more patent following the repeated announcements of climatic changes that will significantly affect areas like the Iberian Peninsula. In already deficit watersheds such as the Guadalquivir Basin of southern Spain, water supplies are expected to diminish, while water demands will increase. Given this scenario, it is essential to develop tools that will aid in determining the behavior of a fundamental climatic variable at the regional level, namely precipitation. Numerous methods which describe rainfall at the regional scale are used to generate synthetic daily precipitation records in locations where observed rainfall records are not available. These methods take into account the effect of geographical variables such as the proximity between stations, or are purely statistical such as the Kriging method. In order to improve the results of classic spatial interpolation methods, new methods are currently being developed to account for variables such as the "proximity between points" not only in the geographical sense (such as distance to the sea and the height above sea level), but also from a climatic standpoint (annual rainfall, average number of wet or dry days and mean precipitation per wet day). In order to estimate the coefficients of the Markov Chain-Mixed Exponential stochastic model, we compare simple interpolation methods such as the nearest station method, the arithmetic mean of the nearest stations or the inverse distance squared method to more complex methods including the Kriging method (with a statistical base) or methods which take into account the geographical and climatic variables described above, namely the multiple regression method, the weighting method developed by Moreno and Roldán and its subsequently improved version and the method based on the application of artificial neural networks to estimate climatic variables.

The purpose of this study was to estimate reference evapotranspiration (ET_o) and rainfall excess (rainfall — ET_o) under climate change conditions for three locations in Puerto Rico: Adjuntas, Mayagüez and Lajas. Reference evapotranspiration was estimated by the Penman-Monteith method. Rainfall and temperature data were statistically downscaled from predictions obtained from the DOE/NCAR PCM global circulation model. The B1 (low), A2 (mid-high) and Alfi (high) emission scenarios of the Intergovernmental Panel on Climate Change Special Report on Emission Scenarios were evaluated. Results from the analysis indicate that the rainy season will become wetter and the dry season will become drier. The average estimated rainfall excess (i.e., rainfall — ET_o > 0) for all scenarios and locations increased in September (the wettest month) to 356.4 mm for the year 2090 relative to an average rainfall excess of 149.8 mm for 2000. The average rainfall deficit (i.e., rainfall — ETo < 0) in February increased to –72.1 mm for the year 2090 relative to an average rainfall deficit of –26.1 mm for 2000. The implications of these results suggest that additional water could be saved during the wet months, which would be needed to offset increased irrigation requirements during the dry months.

Snow water equivalent (SWE) is used to measure seasonal snowpack accumulations. The annual maximum SWE and the rate of snowpack accumulation and melt-off determine the volume of spring runoff. In this paper, the objective is to use exploratory analysis to investigate the effect of variation in El Nino-Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO) on the annual maximum SWE and its associated timing. Traditionally, snowpack was thought to peak around April 1 in the Pacific Northwest. Twenty-five snowpack telemetry (SNOTEL) sites that have more than 20 years of daily records in Washington State were examined first. It was also found that the peaks of snowpack do not occur ten days before and after April 1 in most SNOTEL sites. Then Pearson's correlation coefficient test was applied to examine the relationship between last year's ENSO indices and the current annual maximum SWE and its associated timing for each site. Finally, a simple linear regression model was used to analyze the combined effects of ENSO and PDO as well as their interaction on the annual maximum SWE. Teleconnections between these indices and the annual maximum SWE in Washington State were identified by the exploratory analysis.

The report of the National Science Technology Council's Subcommittee on Water Availability and Quality (SWAQ) surveys the challenges facing the United States today and recommends federal research towards developing collaborative tools and processes for solutions to US water problems. This paper presents a proposal developed under the aegis of SWAQ with experts from this area across the federal water establishment that refines that recommendation by proposing that the SWAQ promote a coordinated federal initiative to develop and advance the integration of computer based modeling tools within multi-stakeholder public decision processes for US water solutions. Components of the proposed initiative include: A review of current uses and programs focused on the use of "collaborative decision support tools"; development of a framework for evaluation of the effectiveness of combinations of various computer tools and collaborative interventions across of range of water problems and settings; and targeted "pilot" or "demonstration" projects, or even "experiments," that can be explicitly designed to be studied and evaluated with the intent of developing recommended approaches and methodologies. The initiative will directly and concretely address the government-wide emphasis on increased use of collaborative processes, and both assist state and local governments and support existing federal water management roles. Federal agencies are well-positioned to conduct and coordinate inter-disciplinary research, and this initiative will provide the efficiency of a central focus for research and knowledge and provide unified direction and consistency over time. Results of the initiative will include focused interagency research on the needs for collaborative problem solving of water problems, coordinated development and dissemination of principles and best practices for effective combination of modeling and multi-stakeholder public processes, and, ultimately, reduced level of water conflict through more broadly-acceptable, timely and sustainable solutions.

The South Florida Water Management District (DISTRICT) is responsible for the operation and management of the Central & South Florida (C&SF) system of canals, structures, pump stations, dikes, and levees in order to balance the needs for flood control, water supply, agriculture, and environmental protection. Hydrologic simulation models are used for analysis of the performance of the hydrologic system. At the regional scale (several counties in size), the DISTRICT has been developing a new, generic model, called the Regional Simulation Model (RSM). RSM is a finite volume code, based on an irregular mesh of triangles. It is an object-oriented design, implemented in C++ and makes use of a variety of commonly available file formats, including NetCDF and HEC-DSS. RSM has two major components: HSE (Hydrologic Simulation Engine) and MSE (Management Simulation Engine). HSE is responsible for simulating the natural movement of water through overland flow, groundwater flow, and in canals and other conveyances, while MSE simulates the management decision process, using operational rules. This paper discusses how the Graphical User Interface (GUI) to the RSM was conceived and developed as a software project using standard project management principles. The GUI has been developed for the RSM, incorporating a collection of tools used to generate documented input files. It provides a streamlined workflow for users of the RSM and automates documentation of the modeling scenarios. It also provides an interface to run the model and provides a collection of tools to post-process output from the model. The GUI uses a combination of a geodatabase, custom geographic information system (GIS) applications and Python applications. The highly detailed geodatabase represents the complex physical hydrologic water features and relationships that are simulated in the RSM. Examination of these elements in the GUI and the resulting files offer a look into the model and the new approach being taken to solve real world problems. When fully developed, the RSM and accompanying GIS tools are expected to be one of the primary DISTRICT modeling platforms for the next decade.

This paper will detail the development of the OASIS Okeechobee Chain of Lakes Model (OKCOL) for the South Florida Water Management District (SFWMD). OKCOL will replace the existing Upper Kissimee (UKISS) model developed in the 1990's. OKCOL uses OASIS' mixed integer linear programming (MILP) engine and automatic non-convex segmentation capability to model hydraulic constraints effectively and efficiently. Those constraints include hydraulicly determined bi-directional flow in free flowing channels. As a result of using the iterative capability built into MILP, OKCOL produces a substantially closer agreement between the modeled flows and the underlying hydraulic equations than does UKISS, which had custom iterative code for simulating the hydraulic constraints. OKCOL is being expanded to include the Lower Kissimee Basin and to screen alternatives for basin-wide operating policy alternatives. The scope and intermediate results of this work will also be described.

Water managers on the Willamette River in the state of Oregon are facing a new biological opinion and potentially strict TMDL regulations for temperature that will require actions by various stakeholders over the next few decades. Considerable public planning has already been accomplished in the basin with much of the assessment and planning phases for solving the basin's problems codified in a TMDL that was issued in 2006. Various alternatives have been proposed to meet the TMDL requirement, including operational changes at US Army Corps-operated reservoirs, projects that increase stream shading or restore the floodplain or hyporheic zone, and operational or technological changes at point sources such as waste water treatment plants and pulp and paper plants. To help meet the TMDL in a shorter time horizon, a collection of stakeholders formed the Willamette Partnership to develop an ecosystem marketplace where water quality and conservation credits can be traded. The marketplace will develop currencies in temperature and other environmental goods and services, and requires tools to describe linkages between credit trades, water operations, and other management changes (e.g. increases in stream shading) that control water temperature. These tools will link basin hydrology to temperature, water quality, and other concerns using a systems dynamics approach to provide real-time feedback to policy decisions. For these tools to be useful at the policy level, they must have short execution times, be able to capture the important dynamics of the problem, and be able to display the output in a manner that is meaningful to the stakeholders. This paper will present the development methodology of those tools, concentrating on the assumptions and comprises that were needed at the model level for the tool to meet those requirements.

The Edwards aquifer is a karstic aquifer which discharges naturally to springs that support a number of endangered aquatic species. Past and projected rates of development and urbanization are high as are the political stakes in managing regional growth and water resources in a sustainable manner. Key issues involve how can development occur or what type of development is acceptable to maintain critical spring flows, water quality, maximum pumping from the aquifer, and environmental quality with intergenerational equity. We are developing a decision support system (DSS) that links scientific and management models that incorporate community stakeholder input, optimization algorithms, and decision analysis tools. The Texas Water Development Board's groundwater availability model is the basis for the DSS. We scale the distributed parameter model (MODFLOW) into a systems dynamics model (POWERSIM©) with links to socio-economic data and stakeholder preferences. Key decision variables include: well distribution and pumping rates, impervious cover, water and sewage line distributions, and stream setbacks. Key outputs include spring flow and water table declines in drought years. Overcoming uncertainties in the relationships between land use, recharge, and aquifer performance is a significant challenge. Understanding the interconnection between systems and hypothesis testing to bracket expected changes in recharge provide valuable information for groundwater management, which we are testing through stakeholder input, including narrative elicitation. The DSS allows comparison of hypotheses about spatial recharge distributions and communication with decision makers in a timely, policy-relevant format that is compatible with Texas policy for quantifying consensus and available yields. This research is being conducted at The University of Texas at Austin and Sandia National Laboratories.

Computer-aided collaborative decision-making has become more important in water resources management as the scope of studies has broadened both in terms of planning objectives and the number of interested stakeholders. Policy judgments and the choice of appropriate investments in water resources involve numerous quantitative and qualitative considerations, which, in the context of multiple stakeholders, can make the decision-making context complex and contentious. Therefore, there has been an increasing emphasis to involve stakeholders in water resource planning and management decision-making, including participation in the analytical modeling process. Such stakeholder involvement is believed to lead to a more efficient decision-making process with more transparent treatment of underlying preferences and mapping of decision processes of multiple people. There are a variety of ways in which computerized models can be blended to support collaborative planning and policy-making. Shared Vision Planning (SVP) is one technique capable of integrating computerized models within a collaborative framework. However, there are likely other processes, perhaps not as formally named, that share common objectives with SVP, but differ in how they integrate physical data and views of stakeholders.

In 2004 the Arizona Water Settlements Act was signed into law, which provides New Mexico and additional 140,000 acre feet of water from the Gila Basin in any ten year period. In addition, the State of New Mexico will receive $66M for "paying costs of water utilization alternatives to meet water supply demands in the Southwest Water Planning Region of New Mexico". Funds may be used to cover costs of an actual water supply project, environmental mitigation, or restoration activities associated with or necessary for the project. Further, if New Mexico decides to build a project to divert Gila basin water, the state will have access to an additional $34–$62 million. To help capitalize on this opportunity in the Gila Basin, Sandia National Laboratories, working with the New Mexico Interstate Stream Commission and the Southwest Water Planning Group has convened a collaborative modeling team. The objective of this team is to develop decision tools to support implementation of the articles of the 2004 Arizona Water Settlements Act. Specifically, an interactive water supply model will be developed to engage stakeholders and decision makers in developing plans for utilizing the water and funds made available through the 2004 Act.

As fresh-water resources in the western United States and the world are pushed beyond their sustainable limits by new and growing demands, increased efficiency in management of water resources is of critical importance if water managers are to reduce social conflict and environmental damages often associated with water scarcity. Computer models and simulations can provide an invaluable tool to inform water management decisions, and can be broadly grouped into two categories: high resolution, computationally intensive models run offline with results communicated to stake holders and policy makers, and lower resolution models that are user friendly and fast enough to allow rapid scenario evaluation by stake holders and policy makers themselves. Ideally, a water manager will have both options available, a rapid scoping model that can be used for real-time, preliminary analysis of a myriad of scenarios, and more spatially/temporally resolved models that can be used for more in depth analysis of preferred strategies. Currently, the main surface water model resource available to decision makers in New Mexico's Rio Grande basin is the Upper Rio Grande Water Operations Model (URGWOM), a daily time-step water operations model for the Upper Rio Grande basin utilizing the numerical software package RiverWare, capable of simulating the hydrology, water storage and delivery operations in the Rio Grande from the Colorado Border to Caballo Reservoir in New Mexico. Because of its size, URGWOM scenario runs are limited to 10 years, evaluate a finite number of scenarios, and take many hours to run. Water decisions and system understanding would benefit significantly from a monthly time-step water operations tool able to mimic the physical system and allow stakeholders to directly interact with the data in real time. That is, a tool that allows the water manager, decision maker, stakeholder, model builder, and public to explore "what if" scenarios to test alternative management strategies and to better understand the cause and effect relations governing the hydraulic system. To develop such a tool, Sandia National Laboratories and the URGWOM technical team have collaborated on development and review of a rapid, monthly timestep model that can be used for rapid approximations of URGWOM behavior. This paper documents the high level development of this decision support tool.

Whereas other shared vision planning studies have typically addressed planning issues for reservoir re-operation issues, there is also a need for the Corps to work with stakeholders to develop a "shared vision" for water management as it performs it's regulatory role under section 404 of the Clean Water Act. Likewise the state of Virginia recognizes the critical role of public involvement in state and local water planning. Therefore, the USEPA, the State of Virginia, and the Corps' Norfolk District regulators are helping guide a pilot Shared Vision Planning in the James River study to identify and describe the water resources management challenges facing growing municipalities in the James basin and to identify strategies for addressing these challenges in support the Corps 404 regulatory role and the State water planning process. A "Pilot" SVP study is proposed to initiate a collaborative process and evaluate the potential for a "full blown" SVP effort. The pilot effort will likely take 3–5 months and will involve several workshops (one or two large workshops plus various meetings of working groups), some model development, limited data gathering and some initial decision-making trials.

A two-dimensional (2D) finite-volume flow solver working on unstructured meshes is developed with using object oriented C++ programming language to solve shallow water equations in conservative form. The solver uses Godunov type second order finite volume scheme in space and fourth order Runge-Kutta scheme in time domain. This solver will be used for flood routing analysis on Ulus Basin with irregular topography, located in the West Black Sea Region of Turkey in an ongoing project. The solver is tested using several dam break cases. The flow solver is also run for 1D case to compare the results with the analytical solutions. Generation of triangular mesh is achieved by using mesh generation software. Water depths simulated after the dam break are compared with the experimental data given in the literature. The shock wave propagation in the channel and time variation of the water depths are prepared in animation form and presented in this paper.

When conducting hydraulic studies or floodplain analysis or when producing DFIRMs for the FEMA map modernization program, two of the more time-consuming processes are setting up the hydraulic model and delineating the floodplain zones. The integration of widely available computational tools with hydrologic and hydraulic modeling and floodplain mapping improves accuracy, effectiveness, and quality. The various tools discussed in this paper include HEC-GeoHMS, HEC-GeoRAS, WISE, CHECK-RAS and RASPLOT. In this paper, the county-wide draft DFIRM of Scott County, Minnesota, is used to demonstrate the applications, capabilities, and challenges faced when using these tools. By using Geographic Information Systems (GIS) raster and feature data sets, HEC-GeoHMS and HEC-GeoRAS automate the pre-processing of input data and post-processing of HEC-RAS results. CHECK-RAS is used to verify the validity of hydraulic parameters, structure and cross section data, as well as floodway and flood profile results. RASPLOT facilitates the creation of flood profiles. These tools are successfully linked with HEC-RAS to expedite the production of floodplain mapping and obtain accurate hydraulic results.

A simulation environment is being developed for the prediction and analysis of the inundation consequences for infrastructure systems from extreme flood events. This decision support architecture includes a GIS-based environment for model input development, simulation integration tools for meteorological, hydrologic, and infrastructure system models and damage assessment tools for infrastructure systems. The GIS-based environment processes digital elevation models (30-m from the USGS), land use/cover (30-m NLCD), stream networks from the National Hydrography Dataset (NHD) and soils data from the NRCS (STATSGO) to create stream network, subbasins, and cross-section shapefiles for drainage basins selected for analysis. Rainfall predictions are made by a numerical weather model and ingested in gridded format into the simulation environment. Runoff hydrographs are estimated using Green-Ampt infiltration excess runoff prediction and a 1D diffusive wave overland flow routing approach. The hydrographs are fed into the stream network and integrated in a dynamic wave routing module using the EPA's Storm Water Management Model (SWMM) to predict flood depth. The flood depths are then transformed into inundation maps and exported for damage assessment. Hydrologic∖hydraulic results are presented for Tropical Storm Allison.

One-dimensional (1-D) and two-dimensional (2-D) hydraulic modeling was used to design the SR 129 multiple bridge crossings of the Canoochee River in southeast Georgia on the coastal plain. This approach produced a bridge cost savings of over $150,000 and illustrates how 2-D modeling can be used to improve the design efficiency and hydraulic characteristics of multiple bridge opening sites. The 2-D hydraulic modeling of the natural and existing conditions was performed using the U.S. Army Corps of Engineers RMA-2 model. HEC-RAS was used for the 1-D modeling of the same conditions, and its multiple opening routine was calibrated to generate similar flow distributions between the bridges for the design storms, and was then used to develop proposed design alternatives. 2-D modeling was then performed for the selected configuration to provide final verification that the design parameters were met.

Urbanization in the coastal area leads to inundation during heavy rainfall is the common problem. The reason for inundation is heavy rainfall, tidal phenomenon, sewerage system, and also rise of sea water level due to global warming. The frequency of heavy rainfall increasing in the recent year cause severe flooding. Flooding poses a threat to life and safety and can cause severe damage to public and private property. The aim of this study is to analysis the inundation situation of Nagoya city due to heavy rainfall considering the effect of global warming. The analysis region is around the Nagoya bay area, Nagoya city, rivers and streams which terminated into Nagoya bay area. Nagoya city is one of the largest city locates in central Japan. Sewerage system in the Nagoya city is also considered in this analysis. Sewerage system performs a vital role to drain the city area during heavy rainfall. The sewerage system is connected to the sea and rivers. Sewerage water is discharged to the sea and river through pumps. In this study, the water behavior due to heavy rainfall and other several cases such as tidal phenomenon existing sewerage system is considered. A synthetic analysis model is developed which includes sea model, inundation model, river model and sewer system model. Developed hydrodynamic model based on finite volume method solving the shallow water equation. The inundation water depth during heavy rainfall is examined by numerical simulation. Moreover, rise of sea water level due to global warming is also considered in this analysis. The inundation in two different cases such as considering global warming and without global warming (i.e. sea water level set 0.95m and 0m) are analyzed. Moreover, the inundation situation is evaluated and finally recommends appropriate mitigation measure is recommended.

In this paper, a new algorithm is presented for flow rating of weir box culverts. Weir box culverts are compound culverts, which consist of a weir box in the front, and a traditional culvert in the back. This configuration makes it quite difficult to obtain accurate flow rating with traditional culvert flow equations. In the new algorithm, flow through weir and culvert is first calculated separately, then iteration method is used to systematically adjust water elevation inside the weir-box and recalculate the flow. This loop keeps on going until the discharge continuity is satisfied with certain convergence criteria. This algorithm has been validated at various weir box culverts. The results show reasonable agreement with field flow measurements.

This paper describes an automated Channel Morphology Tool (CMT) developed in ArcGIS 9.1 environment. The CMT creates cross-sections along a stream centerline and uses a digital elevation model (DEM) to create station points with elevations along each of the cross-sections. The generated cross-sections may then be exported into a hydraulic model. Along with the rapid cross-section generation the CMT also eliminates any cross-section overlaps that might occur due to the sinuosity of the channels using the Cross-section Overlap Correction Algorithm (COCoA). The CMT was tested by extracting cross-sections from a 5-m DEM for a 50-km channel length in Houston, Texas. The extracted cross-sections were compared directly with surveyed cross-sections in terms of the cross-section area. Results indicated that the CMT-generated cross-sections satisfactorily matched the surveyed data.

The U.S. Army Corps of Engineers River Analysis System (HEC-RAS), developed by the Hydrologic Engineering Center, has long been the standard for one- dimensional hydraulic modeling. Despite the wide spread use of the program, even seasoned engineers can fall victim to some common modeling mistakes using HEC-RAS. Four potential modeling mistakes and oversights will be examined herein: (1.) Necessary adjustment of channel bottom elevations for internal bridge cross sections (termed BU and BD in HEC-RAS verbiage), which are copied from the upstream and downstream sections of bridges (Sections 2 and 3 of the bridge sequence) are often ignored and can result in the incorrect computation of the water surface profile within the structure and immediately upstream, (2.) Frequently ignored expansion and contraction coefficients for super-critical flow (most will use just the subcritical flow coefficients) and the drastic impact that the incorrect application can have on the location of hydraulic jumps when in the mixed flow mode, (3.) The overlooked importance of proper cross section spacing through drop structures, and (4.) The need to trim cross sections to a reasonable elevation above the water surface elevation so as not to impact the critical depth computation process is not widely understood and rarely practiced. The impacts on water surface elevation computation for these common errors are not insignificant and can be easily avoided if the engineer is aware of the correct modeling technique. In a field where calculations require accuracy to 0.01 feet, even minor errors in modeling technique can result in unnecessary high cost solutions. The following paper will document these situations through discussion of simple applications and the mechanics of calculation performed by HEC-RAS as well as presentation of methods to improve modeling accuracy. These are subtle errors that even experienced modelers may fall victim to.

The majority of the applications of hydraulic models are performed in 1 spatial dimension. Although nature "operates" in 4 dimensions (3 spatial dimensions and the time dimension), hydraulic engineers often fearlessly model 4-dimensional phenomena with 1-dimensional (1-D) models (sometimes in unsteady mode) knowing fully that the model is just a crude approximation of the real world. These engineers do this not because they willfully want to ignore the other dimensions but rather because of many practical and legitimate reasons. In certain applications where a 2-dimensional (2-D) depth-averaged model might be warranted, an experienced engineer can sometimes finesse a 1-D model and extend its capabilities such that the model can reasonably emulate 2-D phenomena or use an external application that can be used to adjust the 1-D results for 2-D application. This paper presents such techniques and also explains the cautions/limitations of the techniques. The paper will use HEC-RAS as the example model since it is the most widely used 1-D model.

Considerable empirical formulae have been developed for wind-driven gas-liquid transfer rate. These empirical relationships are normally limited in their applicability due to the specific experimental conditions under which they were developed. A more generally applicable relationship on wind-driven gas-liquid transfer rate was derived from the formula of wind-stream-driven gas-liquid transfer rate. Thus, the formula of wind-driven gas-liquid transfer rate developed in this study is reasonable as a specific case when flow velocity equals zero. Using this general wind-driven gas-liquid transfer rate formula, differences between empirical formulae can be explained based upon variations in the equivalent thickness coefficient of the overlap layer (Γ). Agreements between the general model and the Liss-Merlivat formula were obtained for wind speed from 1 to 8 m/s when Γ = 16; while for similar wind speeds, agreements with Wanninkhof's formulae were obtained when Γ = 4. Some other values of Γ were obtained by applying this general formula on other sets of experimental data. The significance of the formula as well as the effects of the equivalent thickness coefficient of the overlap layer (Γ) to the prediction of wind-driven gas-liquid transfer are discussed.

This paper presents the development and application of an integrated surface water and groundwater model to simulate hydrodynamics and thermal and salinity in tidal water bodies and subsurface media. The hydrodynamic module for tidal waters solves three-dimensional Navier-Stokes equations with or without the hydrostatic assumptions. The Richards equation is used to simulate the subsurface flow in both vadose and saturated zones. The Boussinesq approximation is employed to deal with the buoyancy force due to temperature and salinity variations. The moving free surface is explicitly handled by solving the kinematic boundary condition equation using a node-repositioning algorithm. The transport module solves the energy equation for temperature distribution and the mass transport equations for the salinity fields. The Arbitrary Lagrangian-Eulerian (ALE) representation is adopted for all transport equations including momentum transport. The solution is obtained with finite element methods or a combination of finite element and Semi-Lagrangian (particle tracking) methods. The model has been calibrated with tidal and salinity measurements at five locations in Loxahatchee River Estuaries. The calibration of groundwater flow and subsurface salinity transport is not as satisfactory. Further study to downscale the MODFLOW hydraulic conductivity is needed to better reflect the fine grid used to discretize the groundwater module in the present study. A better conceptual model to deal with the interface between surface water and subsurface water and to handle flood plain is warranted.

Following the April 2000 flood on the Tisza River, the Ministry of Water Resources of Hungary authorized the Middle Tisza-Valley District Water Authority to investigate available computer models and make recommendations regarding model selection. The goal of this paper is to summarize the ongoing hydrologic modeling activities during the past few years.

A coastal/estuarine process model was applied to investigate the hydrodynamics and morphodynamics in an estuary under combined physical forcings, i.e., tides, waves, winds, and river floods, including the extreme cases of three typhoons and one 100-year flood events. Numerical simulations by the computational model revealed complex flow patterns and morphodynamic changes in the estuary, e.g., coastal inundation, breaching of a rivermouth sand bar, and erosion/deposition due to tidal currents, river flood flows, and wave-induced currents. These results are important to the understanding of sediment transport and morphological processes especially during storms and floods, and furthermore, can be used in planning for flood protection, sediment management, and shoreline stabilization in the region.

The National Ocean Service (NOS) has developed an operational nowcast/forecast system for Galveston Bay using a modified version of the Blumberg-Mellor three-dimensional hydrodynamic model extended to orthogonal coordinates by Blumberg and Herring as discussed by Schmalz. The nowcast component works directly from the National Water Level Operational Network database using standardized readers. During the forecast component the National Weather Service's North American Mesoscale, River, and Extratropical Storm Surge models are used to provide the meteorological, surface water inflow, and Gulf of Mexico subtidal water level forcings, respectively. In addition, a one-way coupled higher resolution Houston Ship Channel model has also been incorporated into the system. Hourly nowcasts of the previous 24 hour period and four times daily 30 hour forecasts of water surface elevation and currents, as well as three-dimensional temperature and salinity are performed using both bay and channel models. Initially, hindcast studies over June 1995, January 1995, October 1994, and April 1996 were performed to validate the models for tidal and subtidal effects. Next, prior to operational implementation, the experimental nowcast and forecast results were assessed over the one-year period April 2000 through March 2001 based on the NOS formal acceptance statistical criteria. The methods to estimate numerical uncertainty in computational fluid dynamic computations proposed by Roache are investigated as to their appropriateness for these three-dimensional, unsteady, stratified, estuarine flow models. We first examine the basic procedures. Next we suggest how they might be applied to the bay and channel hydrodynamic model calculations. We consider both the hindcast and nowcast/forecast calculations. Potential difficulties and challenges are outlined for both calculation types. Finally, next steps are advanced to seek to improve the validation procedure.

Understanding the hydrologically-driven erosion processes that control sediment detachment, transport and deposition on upland surfaces is a major challenge in watershed erosion modeling. This paper presents a sediment transport algorithm with a coupled 2-D surface and 3-D subsurface flow model that can simulate surface responses and also consider subsurface contributions during a rainfall event, hi the model, the sediment transport algorithm utilizes the non-equilibrium concept to simulate both erosion and deposition. The flow and sediment transport equations are discretized using the finite volume method and solved implicitly using the Picard iteration method. The flow and sediment transport are computed in a decoupled way; that is, the depth-averaged 2-D sediment model is solved after the flow field simulation at each time step. The developed sediment transport model is tested using measurement data from published experiments. The ability to simulate sediment transport due to rainfall in a watershed is demonstrated.

The 26.5-mile Lower Willamette River (LWR) in Oregon, extending from the Willamette Falls to the Columbia River, is a dynamic system. Modeling the hydrodynamics and sediment transport is an important element of an ongoing remedial investigation/feasibility study. (RI/FS) in the portion of the LWR, referred to as the Portland Harbor Superfund site. This paper describes a phased approach to develop a comprehensive hydrodynamic and sediment transport model to assess sediment stability/erodibility in Portland Harbor. Model setup, calibration, and validation are presented. The paper also discusses how well the model results meet the objectives of the Phase 1 modeling effort and how the model performance can be further improved.

Sediment transport in a gravel-bed mountain stream, the Upper Spanish Creek, California, was simulated with a depth-averaged, two-dimensional hydrodynamic and sediment transport model. The hydrodynamic model is based on the solution of depth-averaged flow continuity and momentum equations with dispersion terms to account for the effect of secondary flow. The sediment transport model treats bed load and bed material as mixtures of multiple grain-size sediment. Changes in bed elevation are calculated by solving the sediment mass conservation equation. The model was applied to predict bed-load transport in the Upper Spanish Creek to identify areas of high-erosive potential that require bank protections. Results of this verification process demonstrated the applicability of the two-dimensional hydrodynamic and sediment transport model to assist river restoration designs for gravel-bed streams.

The database from a Large Eddy Simulation (LES) calculation is used to investigate the dominant coherent structures in the wake of a vertical bridge abutment in a straight channel with deformed bed corresponding to equilibrium scour bathymetry. The bathymetry is obtained from an experiment conducted at the same Reynolds number. The incoming flow is fully turbulent in both experiment and simulation. Dye visualizations are used to validate the numerical predictions. It is observed the directions at which the eddies are shed in the separated shear layer change as the bed is approached. In average, the separated shear layer curved toward the lateral wall as the bed is approached. The eddies shed into the separated shear layer can entrain sediment as they are convected. This may explain one of the mechanisms responsible for the development of the scour hole in the region behind the abutment. It is also observed the formation of large scale bed forms strongly increases the complexity and three-dimensionality of the flow in the region situated between the detached shear layer and the lateral wall downstream of the abutment. In particular, a streamwise elongated submerged mount of sediment (hill) is observed to form downstream of the abutment. As a result, two streamwise-oriented vortices are identified in between the submerged hill and the lateral wall. It is found the movement of the fluid inside these vortices may be either in the flow direction or in the reverse flow direction depending on the streamwise position along their axes. The influence of these vortices on the sediment transport within the recirculation region past the abutment in the later stages of the scouring process is discussed.

A numerical model study of the Hoosic River in North Adams, MA was conducted to determine flow conditions at up-dated flood discharges. The study reach of the Hoosic River is a man-made concrete lined steep channel. The flows are conveyed as supercritical. The design of this high-velocity channel was evaluated and refined in a physical madel study completed in the 1950's. The current study is a validation of the Adaptive Hydraulics (ADH) shallow-water code to capture the flow features within this complicated channel. The ADH code was used to simulate the supercritical flow and the results are compared to the physical model data. The project is a good test of the model's ability to simulate the complicated flow throughout the study reach. The reach contains 23 curves with compound spirals and invert banking, a confluence of two supercritical channels, and a twin stilling basin to contain hydraulic jumps prior to introducing the flow to a soft-bottom channel. The longest tangent between compound curves is less than 5 times the channel width. Most curves are adjoined in that the spiral-to-tangent (ST) ending one curve and the tangent-to-spiral (TS) beginning the next curve share the same station. The numerical model results are compared with previously published physical model data. Issues such as mesh adaption and resolution are investigated. Also the ability of the shallow-water equations to simulate the additive effects of adjoining curves is tested.

Rapid advances in state-of-the-art computational fluid dynamics (CFD) analyses are being made in simulating multi-phase flow fields, particularly where fluid-structural member interactions, air-water interfaces (free surfaces), and bubbly mixtures are involved. Coupled equations link the Navier-Stokes equations of fluid motion with structural deformation equations to simulate both fluid and structural response to either steady-state or transient boundary conditions. Consequently, defensible calculations that are based on the best formulas used in engineering practice can be utilized for comprehensive hydraulic structural design. Problems associated with frothy free surfaces, bubble formation, and air migration can now benefit from CFD implementation of research results regarding two-phase, air-water flow. A case study which illustrates the benefits of CFD analyses to guide difficult hydraulic structure designs is presented. The case study consists of supercritical flow in a steep pipeline with sharp curves and converging flows. The pipeline normally flows under open-channel flow regime, but air bulking and run-up could potentially cause undesirable hydraulic performance. The CFD analysis was used to evaluate these turbulent flow conditions which could reduce the pipeline flow capacity and cause other undesirable flow characteristics. Information determined from the CFD analysis provided valuable guidelines in developing the final design.

The flow over bed forms consists of contracting flow, flow separation and expanding flow. Typically, flow separation occurs near the crest of the bed form with flow re-attachment on the adverse slope. Flow acceleration occurs on the upstream side, while flow deceleration occurs at the lee side of the crest of the bed form producing an eddy and generating localized turbulent kinetic energy. This conversion of the mean kinetic energy into turbulent kinetic energy results in additional energy losses related to form drag. In this study, multi-beam bathymetric surveys and ADCP data collected from the Lower Mississippi River by the United States Army Corps of Engineers were used to setup a set of high resolution three dimensional computer models utilizing HydroQual's Estuarine and Coastal Ocean Model ECOMSED, the Danish Hydraulic Institute's (DHI) MIKE 3 hydrodynamics flow model and Hayco's three dimensional circulation model H3D.

Techniques of distributed hydrological modelling, stakeholder land use mapping, and statistics were used to analyse the effects of rewetting and wetlands restoration at catchment level. The aim of this approach was to determine the catchment's response to the different types and geographical distributions of wetlands. Identification of potential sites for wetland restoration was based on soil properties and elevation data. Wetland restoration scenarios were then created that incorporated natural upstream-downstream catchment relationships. The four scenarios simulated were (a) Infiltration restoration, (b) Upstream headwater wetland restoration, (c) Downstream valley bottom wetlands restoration, and (d) Upstream valley bottom wetland restoration. The results point to river valley rewetting as having the effect of decreasing the paved overland component of stream flow, and increasing the saturated zone flow component. It promotes groundwater recharge. The catchment's actual evapotranspiration and root zone water responses were found to be varied, and were the consequence of a number of factors. This further proved the case that generalisation of wetland functions are of little use due to a high variability in local conditions, climatology and topography of the reported catchments.

Traditional assessment of surface water quality based on gap samples of discrete dissolved oxygen (DO) is often limited by large diurnal fluctuations. A common reference time for DO measurements is needed for better assessments of differences among water bodies and for identifying changes with time. Two different models have been developed by the authors to convert a DO measurement at any diurnal time to a DO value at a reference time. Both models are based on an extended stochastic harmonic analysis (ESHA). One of the models is formulated using the fraction of DO saturation. It requires real-time (continuous) and discrete data for both DO and water temperature for parameter estimation and an observed DO value with water temperature data in its application. The other model is formulated using only DO and, therefore, does not require water temperature data in estimating parameters as well as in application. Both models were evaluated for the same network of different stream sites across Minnesota, incorporating effects of different ecoregions and variable drainage areas. This paper draws contrasts between the frameworks and performances of the two models. Data were normalized in both cases to increase the general applicability of the fitted parameters. Each of the algorithms revealed good performance in representing observed diurnal variations in DO. For the fraction of DO saturation model, the root mean square error (RMSE) of predicting hourly DO and standard DO ranged from 0.43 to 0.77 mg/L and 0.37 to 0.90 mg/L among the five streams, respectively. In contrast, the RMSE for predicting hourly DO and standard DO respectively ranged from 0.53 to 0.80 mg/L and 0.44 to 0.91 mg/L with the DO only model. While the two models showed nearly equivalent modeling accuracy and consistency, the DO only model added to the elegance of ESHA algorithm for its simpler framework and single parameter (i.e., DO) input data requirement. Both models are useful tools for total maximum daily load (TMDL) assessment of aquatic ecosystem health across a range of temporal and spatial scales.

Within the Prairie Creek 1 area of Midewin National Tallgrass Prairie, invasive woody vegetation was identified as limiting species indigenous to the savanna community. Removal of the undesirable woody vegetation was planned to rehabilitate the savanna. The project area was divided into an experimental and reference areas. Following the invasive removals at the end of the growing season there were statistically significant differences in soil moisture levels between the two sides, with increased soil moisture content within the experimental area. Also, the ground water depths were statistically different. It was concluded that the observed changes in soil moisture content and depth to ground water were directly related to removal of the woody vegetation from the experimental area.

Traditional culvert designs, in many cases, have become habitat barriers to aquatic and terrestrial animals. In response, environmentally sensitive culvert designs have been developed that function as ecological bridges. Bottomless and buried invert culverts are examples of such designs and are commonly used for fish passage. Additional design guidance specific to streambed stability in buried-invert or bottomless culverts under high flow events is needed. This study investigated incipient motion conditions for three substrate materials in a 0.61-m (2-ft) diameter circular bottomless culvert in a laboratory setting. This paper discusses the experimental methods used to determine incipient motion conditions and an incipient motion prediction method based upon substrate size (d_m), which may be useful for determining stable stone diameters to be used as riprap in simulated streambeds through bottomless and buried-invert culverts.

Based on the surface renewal model and Moog and Jirka's study, the oxygen transfer coefficient can be related to the turbulent energy dissipation rate near the water surface. Following this approach, two new formulas were derived to calculate the oxygen transfer coefficient in open channel flow. In these two formulas, the oxygen transfer coefficients were calculated using water depth and surface velocity or depth-averaged velocity. Good agreements were observed by comparing these two formulas with the experimental data obtained from open channel flow without any wind effects. These newly proposed formulas can be adopted in two-dimensional or three-dimensional water quality models to calculate the oxygen reaeration rates.

Headwater streams are ecologically significant areas. In Southern Ontario these ecosystems are under increasing stress due to urbanization, water takings and other human activities. Longitudinal connectivity is an important ecological process that should be considered when setting flow targets for headwaters. Hydraulic models are effective tools for assessing connectivity. The one-dimensional (1D) HEC-RAS simulation software is favored in Ontario because it is familiar to the staff of watershed management agencies. Good performance of 1D hydraulic models under low flow conditions has been achieved for a number of stream reaches in Southern Ontario, provided that survey data adequately represents hydraulic controls such as riffle crests. However, 1D models of headwater reaches have been less satisfactory for the purposes of ecological flow assessment. Three challenges have been identified that may contribute to model error including stream complexity, effects of coarse woody debris and spatially variable discharge due to local regions of subsurface flow. These challenges are discussed in the context of proposed fieldwork and analysis methodologies aimed at developing effective techniques for low flow analysis in headwater streams.

The Bureau of Reclamation (Reclamation) is currently studying various alternatives to improve salmonid habitat throughout the Yakima Basin in central Washington. In an effort to accomplish this goal, Reclamation is evaluating the effects of modifying flow releases throughout the year and increasing storage in the basin. A two-dimensional (2-D) hydraulic model has been used to identify various habitat types, including off channel habitat, spawning habitat, and pools, riffles, and glides for a wide range of flow rates. Spawning habitat was identified with Froude values between 0.3 and 0.6 using independently collected spawning data. Off-channel habitat is identified as side channels become active at various flow rates. Pool, riffle, and glide habitats are identified by assigning each habitat type a specific range of the Froude number. The results were verified through field investigations of the modeled reaches. The major component of a 2-D hydraulic model is well-defined stream channel geometry. This type of data can be difficult to obtain, particularly for long study reaches. To resolve this issue, water penetrating airborne LiDAR was used to map approximately 153 river kilometers of bathymetry on the Naches and Yakima Rivers. This data was then combined with terrestrial LiDAR to create a complete surface with which to model hydraulics. The ability of airborne LiDAR bathymetry to map shallow water river environments is in early stages of development. The accuracy and precision of those measurements is summarized.

Installing groynes in a river has important implications for controlling the scouring process along river banks, maintaining channels for navigation, restoring fish habitat and on the mass transport processes. In many rivers flooding occurs several times a year causing most groynes to become submerged. The momentum convected into the embayment between successive groynes by the flow overtopping the groyne crest can significantly change the whole circulation pattern inside and around the embayments. In the submerged case the embayment can exchange momentum and mass both horizontally via the lateral channel-embayment interface and vertically via the roof interface. Thus, studying the effect of submergence on the momentum and mass transfer processes at groyne fields is important. Large Eddy Simulation is used to investigate the dynamics of the main coherent structures present in the flow around two vertical submerged groynes situated in a long flat-bed open channel. The Reynolds number defined with the height of the groyne D and the bulk channel velocity, U, is Re=13,600. The total channel depth is h=1.4D corresponding to flood conditions and the incoming channel flow is fully turbulent. The statistically averaged three dimensional (3D) vortical structures located in the upstream recirculation zone, embayment, detached shear layers, and downstream of the second groyne are visualized and the flow dynamics in these regions is described. The differences between the instantaneous coherent structures in the turbulent flow and the vortical structures present in the mean flow field are also highlighted and explained. The role of these large scale structures in the mass exchange between the embayment region and the main channel is investigated.

A calibrated 2D hydrodynamic model of a popular recreational fishing reach in the tailwater of the Caney River was employed to evaluate the benefits of trout habitat enhancement with a boulder cluster field. Hydrodynamic modeling results were coupled with habitat suitability index (HSI) Models to quantify relative enhancement at a flow of 174 m³/s. Scenarios with alternative boulder cluster densities were simulated to obtain an optimum design density for juvenile Rainbow Trout based on the computed weighted usable area (WUA) from the coupled model output. The model predicted an optimal spanwise spacing B=1.50D₀–1.67D₀ and streamwise spacing L=2.00D₀–2.33D₀; where D₀ represents the least dimension of the base area of each cluster. The simulated boulder cluster field was located along the gravel bar approximately 80 m from the right bank, and occupied a 4800 m² area with 240 m streamwise length and a 20 m spanwise length. Each individual boulder cluster was composed of two layers of boulders, each of approximately 1 m in diameter. The study demonstrates a rationale methodology for designing a boulder cluster field in a tailwater that is subject to the frequent occurrence of high flows. However, the assessment of WUA is found to be sensitive to both the weighting coefficients and the suitability index (SI) curves; which in turn depend on the flow discharge, the trout species and the life stage being considered.

Particulate matter transported by the urban rainfall-runoff represents a wide gradation of particles from colloidal sizes to gravel and debris sizes. These particles are a potential concern not only because of the environmental and ecological issues related to particles, but also since many contaminants are bound to the surface of particles and transported through the aquatic environment. This study examined rainfall-runoff events captured from an instrumented MS4 watershed. Untreated runoff has higher accumulative mortalities than runoff treated through only physical filtration; indicating the role of particulates on toxicity. The LT₅₀ and NOET values indicate that higher particulate loads associated with mass-limited events were most toxic; and for mass-limited events that toxicity decreased across the event. Oxygen consumption results indicate as total particulate concentrations increase, the suspended particles are more toxic than settleable and sediment particles. Information in this paper is helpful in selecting unit operations targeted for controlling the particulate quality of runoff through a unit operation and process design approach for BMPs in order to improve for toxicity reduction through the separation of particulate matter.

Previous investigations into the effects of turbulence on fish habitat utilization have used statistical metrics which measure the amplitude and frequency of velocity fluctuations in a flow. The results of these studies have been mixed; some show increased habitat utilization with increased turbulence while others show the opposite, no, or dome shaped trends. The result for most stream restoration and fish passage designs has been either to ignore or to simply "minimize" turbulence levels. To clarify the results, a set of novel experiments has been performed, with the specific goal of investigating the importance of the physical structure of the flow and its relationship to fish habitat. Seven separate turbulent flow conditions were created and characterized in a 60 cm by 60 cm flume. Data on the size, orientation, and circulation of eddies using Particle Image Velocimetry (PIV) were collected. Creek chub, semotilus Atromaculatus, were swum in each of the seven turbulent flow conditions under an increasing velocity test. For creek chub, orientation, size, and circulation are strongly correlated to the ability to station hold in a flume. The size, circulation, and orientation of eddies are governed by channel and obstruction geometry, bulk flow conditions, and distance from the turbulence source making stream restoration and fish passage . designs possible based on a few simple relations. These relations describe the eddy composition of a flow in terms of size, vorticity, and frequency as a function of the Reynolds number and location in the flow.

On 28 August 2006, U.S. News & World Report ranked undergraduate engineering programs accredited by the Accreditation Board for Engineering and Technology. Fifty-nine of these programs were located at schools whose highest degree was a doctorate. The present study addresses the hypothesis that more highly ranked programs have broader humanities requirements than lower ranked programs. The term "humanities" is defined in the National Foundation on the Arts and the Humanities Act of 1965 to include "the study and interpretation of the following: language, both modern and classical; linguistics; literature; history; jurisprudence; philosophy; archeology; comparative religion; ethics; the history, criticism, and theory of the arts; those aspects of the social sciences which have humanistic content and employ humanistic methods; and the study and application of the humanities to the human environment with particular attention to reflecting our diverse heritage, traditions, and history and to the relevance of the humanities to the current conditions of national life." Applying this definition, the graduation requirements of a statistically-significant sample of the 59 programs are compared to the U.S. News & World Report ranking of the selected programs. Conclusions are presented.

This paper addresses the incorporation of field experiences into the undergraduate curriculum. Specific field applications were introduced in a fourth-year hydrology course and a first-year introductory civil engineering course in the Civil and Environmental Engineering (CEE) Department at Worcester Polytechnic Institute (WPI). In the hydrology course, field equipment was used to monitor flows and quality in urban streams, as required for projects involving urban runoff. For two course offerings, "linked" projects were developed in which students from upper-level classes worked with the students in the first-year course. All of the students gained experience setting up field experiments and working in teams, while the upper-level students gained some experience by leading the field effort and explaining the use of the equipment to younger students. Student feedback was positive, with students appreciating the hands-on projects and hands-on experience involves in the projects. Additional field experiences are being incorporated into team capstone CEE projects, which are completed by fourth-year students. By including field experiences in these projects, students gain an appreciation for the planning and careful consideration required when completing field programs. The results illustrate the importance of incorporating fieldwork into the undergraduate curriculum.

Recruiting women for engineering and science programs is a major focus for many U.S. universities and for our nation in general. Studies have shown that there are specific actions that can be taken to improve those recruiting efforts including K-12 outreach, presenting engineering and science as "caring" professions, and providing hands-on opportunities for students. Learning/living communities have been shown to be an effective tool for retaining undergraduate students in general. The concept of a learning community has been combined with the "caring" concept to attract and retain women interested in studying engineering and science by focusing on water supply studies to reduce infant mortality rates in rural Guatemala. Students enrolled in the learning community class field trip have the opportunity to participate in a field trip to Guatemala. The water study materials have been incorporated into pre-college outreach because a quantitative yield analysis has shown that hands-on pre-college programs are effective at recruiting women.

The Southwest Florida Council for Environment Education, Inc. (SWFCEE) is a 501(c)(3) non-profit organization dedicated to promoting and expanding environmental studies in the community. SWFCEE is working to help students from pre-kindergarten through post-graduate studies learn more about our unique Florida environment. Environmental education is important so that students come to understand the diversity and value of our local ecosystems. The environment also serves to stimulate and excite students to pursue all areas of learning. However, environment educators don't always have the financial resources necessary to maintain and expand successful programs. Under a local board that consists of a varied mix of developers, contractors, engineers, environmental consultants, architects, attorneys, realtors, university professors, resort hotel owners, and local utility company managers, SWFCEE was established to help our community invest in these valuable environmental education pursuits. SWFCEE also works to establish partnerships between environmental education programs and donors willing to support these efforts.

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 describes the opportunities for the water resources community to participate in NASA's Water Management Applications Program.

Environmental pollution can be perceived as the by-product of discharging and dumping material, heat and waste into the environment through human activities of production and consumption. When a compound is added to fresh water, it will be dissolved and diffused throughout the water body. The dissolution and diffusion imply an increase in the entropy of the matter (by virtue of its definition and the second law of thermodynamics) and an increase in the degree of pollution. This implies that water pollution results in an increase in entropy. Water is extensively used in cooling, washing, disposal of waste material and dissipation of waste heat. Water pollution can then be viewed as a source of increasing the entropy of the river. Thus, entropy can serve as a unified index for assessment of water pollution and a means of controlling it. It has also been used in information management and reducing the data redundancy with applications in water quality management. This paper explores the potential of measuring entropy for solving waste-load allocation problems. The objective function of the optimization model is to minimize the entropy of polluting the river. The model is used as an optimization tool to find the optimal removal fraction at the point sources in order to minimize the total increase in entropy of the river. The model is applied to a case study in southwestern Iran.

The Guatemalan Highlands is a popular destination for non-government organizations interested in performing relief projects. U.S.-based organizations such as Rotary International, Engineers Without Borders, and various religious organizations travel to Guatemala to conduct humanitarian activities which may be effective for the short term, but it is not clear that the efforts have a systematic impact. Students and faculty at the University of Missouri-Rolla have systematically studied water supply issues including undergraduate and graduate research projects and undergraduate engineering courses such as international capstone design. Materials engineers have been involved in the study of ceramic-based water treatment devices. These microfilters have the potential to be fabricated locally using locally-available materials. The academic program has resulted in the establishment of a collaborative relationship with the University of San Carlos in Quetzaltenango, Guatemala which provides opportunities for U.S. and Guatemalan scientists, engineers, and educators to address long-term water supply issues in the highlands.

Current U.S. Army Corps of Engineers guidance stresses the need for integrated and systems types of analyses. ER 1105-2-100, the Planning Guidance Notebook, and more recently ER 1105-2-409, Planning in a Collaborative Environment, emphasize the need for a collaborative and coordinated decision making process that considers more than the traditional Corps' interests. In fact, the first point of the Corps' recently announced 12 Actions for Change is for the Corps to employ an integrated, comprehensive and systems based approach. Unfortunately at this time, a tool to perform a coordinated and collaborative analysis does not exist. This tool would have to accept input from multiple disciplines and for multiple purposes. Numerous agencies, consultants, NGO's, and other stakeholders who participate in these studies would have to have access to this tool. To address this need, the Corps' Hydrologic Engineering Center (HEC) has been developing an interface called the Watershed Analysis Tool (HEC-WAT or the WAT). The primary purpose of the WAT is to streamline and integrate a water resources study using software commonly applied by multi-disciplinary teams. By using a "plug-in" concept the WAT incorporates individual pieces of software such as our suite of software (HEC-RAS, HEC-HMS, HEC-ResSim, HEC-EFM, HEC-FIA, and HEC-FDA) and allows them to work together in a coordinated fashion so that water resources, economic, and environmental decisions can be made from the same interface. As the WAT matures, additional pieces of software will be incorporated into the WAT that will allow additional analyses and decisions to be made. The individual models use a shared schematic (representation of the physical system) that is developed by the Project Delivery Team. The shared schematic assures that the naming convention and project identification and location for the study is consistent throughout the modeling disciplines. The modeling files from the individual pieces of software will be stored in the WAT architecture so that the project files are located in a common site for easy retrieval and documentation. Output and alternative analysis comparisons from the models will be accessed directly from the WAT making the results and reporting from all the models much more accessible. These features and additional capabilities of the WAT will promote integrated water resources modeling and decision making and support the policy needs identified above. This paper will discuss the development, functionality, capabilities, benefits, requirements and application of the WAT to water resources studies.

The Framework for Risk Analysis in Multimedia Environmental Systems (FRAMES) is decision-support middleware that provides users the ability to design software solutions for complex problems. It is a software platform that provides seamless and transparent communication between modeling components by using a multi-thematic approach to provide a flexible and holistic understanding of how environmental factors potentially affect humans and the environment. It incorporates disparate components (e.g., models, databases, and other frameworks) that integrate across scientific disciplines, allowing for tailored solutions to specific activities. This paper discusses one example application of FRAMES, where several commercial-off-the-shelf (COTS) software products are seamlessly linked into a planning and decision-support tool that helps manage water-based emergency situations and sustainable response. Multiple COTS models, including three surface water models, and a number of databases are linked through FRAMES to assess the impact of three asymmetric and simultaneous events, two of which impact water resources. The asymmetric events include 1) an unconventional radioactive release into a large potable water body, 2) a conventional contaminant (oil) release into navigable waters, and 3) an instantaneous atmospheric radioactive release.

Hurricane Katrina resulted in damage and destruction to local water supplies in Mississippi and Louisiana affecting millions of people. Immediately following the devastation, a multidisciplinary team of 30 EPA emergency response, research, and water program personnel joined forces with local health and environmental officials to help residents with access to safe drinking water supplies from hurricane-ravaged parishes surrounding New Orleans, LA. The EPA team met at the EPA Region VI Emergency Response Center in Dallas, Texas to prepare for assessment of over 400 public water supplies. EPA employees loaded SUVs, vans, and trucks with emergency response supplies and drove 9 hours to Livingston, LA. The EPA team began working 12- to 14-hour days for 10 straight days to restore safe drinking water to Louisiana communities. Each EPA person was paired with an inspector from a State Rural Water Association (LA, TX, GA, IN, IA, and IL were represented), or with someone from LA Department of Health and Hospitals (LDHH). Major problems included; loss of power/loss of pressure, no backup generators (as many as 60 generators were requested), and damage/destruction to treatment plants and water distribution systems. Water systems were categorized on the basis of type of water company (community, non-community, or transient), severity of damage, need, whether they had been visited already by LDHH, and accessibility considering flooding and loss of infrastructure (electrical power and roads). After the landfall of Hurricane Rita, a second team of EPA Office of Research and Development microbiologists assisted EPA Region VI with analysis of bacteria samples from public water systems at a mobile laboratory near Lake Charles, Louisiana.

In collaboration with Clermont County, the U.S. EPA's Office of Research and Development is developing watershed-wide load and transport models to account for stream processes at the Experimental Stream Facility in Milford, Ohio. To better understand environmental stressors in stream flow and the structure and function of stream ecosystems, researchers are establishing continuous water quality monitoring stations along the Lower East Fork River and its tributaries. In conjunction with this effort, EPA and the University of Cincinnati are developing a non-line-of-sight digital datalink using a high frequency radio for telemetry of environmental data with a direct 50-mile range. Features of this design include real-time continuous monitoring of remote sensor measurements, all-weather 30MHz transmission (without repeaters), and solar-powered remote telemetry stations. Remote sensor data is transmitted to a central monitoring station from a network of water quality sensor sites for alarms, analysis, and archiving purposes. Small VHF transceivers can be integrated into the communications network for shorter distance data links where numerous sensors are necessary. Applications include watershed source monitoring, treatment facility data collection, and water storage quality validation.

The effects of three manure treatments on estrogen removal (E2 and E3) were examined in this study. Samples were taken from a full-scale manure handling system incorporating manure separation and aeration (System I), an anaerobic digester receiving dairy manure (System II), and anaerobic slurry from three commercial dairy farms (System III). E2 and E3 were analyzed using enzyme-linked immunosorbent assay (ELISA). Significant differences were found in the ratios of estrogens to total solids in land-applied manure among the three treatment systems (P < 0.05), with System II yielding land applied material of the highest estrogen content. System I significantly reduced the total mass of E2 and E3 found in land applied material compared to the influent (P < 0.05). The upstream solid separation process in this system did not remove E2 or E3; all removal by the system was due to the downstream sequential aeration process. The mass of E2 (P < 0.05) but not E3 (P > 0.05) was significantly decreased in System II, although it is unclear whether this removal was due to biodegradation or sorption to sludge. Future work will focus on this question, as well as the effect of treatment on total estrogenic activity. Manure treatment systems designed for nutrient management purposes also influence the estrogen content of land applied waste.

Endocrine-disrupting compounds (EDCs) have been detected in natural waters globally. Additionally, trace concentrations of Pharmaceuticals and personal care products (PPCPs) have also been detected in various waters, primarily as the result of incomplete wastewater treatment. Some PPCPs are known to act as EDCs as they can have impacts on the endocrine systems of animals. The detection of EDCs and PPCPs in source water is of great concern since some of these compounds have known physiological responses at low concentrations. The majority of EDCs and PPCPs are more polar than traditional contaminants, such as polychlorinated biphenyls (PCBs) and organochlorine pesticides, and several have acidic or basic moieties. These properties, coupled with trace quantities, create unique challenges for both removal processes and analytical detection. There are two general approaches for monitoring EDCs and PPCPs in water: 1) direct measurement of target compounds via analytical instrumentation and 2) biological assays. The use of liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) has provided highly sensitive and selective analysis of a great diversity of emerging contaminants [1,2]. LC-MS/MS can also be advantageous as it does not require labor intensive derivatization for polar compounds that is necessary for traditional gas chromatography (GC) analysis and does not require additional sample clean-up or solvent transfer steps [3]. This presentation will describe using isotope dilution and LC-MS/MS for the analysis of EDCs and PPCPs. Samples are spiked with isotopically-labeled versions of target compounds and extracted using automated solid-phase extraction (SPE). The resulting extracts are analyzed by LC-MS/MS using both electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) in positive and negative modes. Isotopically labeled standards can be a useful tool for the correction of recovery loss, instrument variability and matrix suppression or enhancement [4]. Although APCI does not exhibit significant matrix suppression as compared to ESI, it can be less sensitive and compound dependent. Method reporting limits ranged from 0.25 – 10 ng/L in a variety of water matrices based on a 1 to 1000 concentration factor (Table 1). Percent recoveries ranged from 91 – 116% with percent relative standard deviations (%RSDs) from 0.7 – 10% for all three water matrices. Figure 1 illustrates how recovery loss from solid phase extractions in DI water can be corrected by the use of isotope dilution. Figure 2 compares occurrence data of pharmaceuticals detected in surface water that was quantified using external calibration versus isotope dilution. External calibration data appears to be suppressed by recovery loss and matrix suppression. This can result in data that underestimates environmental concentrations or reports them as non-detect. Although there are some limitations, LC-MS/MS using isotope dilution can be used to measure EDCs and pharmaceuticals in a variety of matrices with exceptional sensitivity and selectivity while generating data with better precision and accuracy.

The occurrence and risk management of endocrine disrupting chemicals (EDCs) and pharmaceuticals and personal care products (PPCPs) are topics receiving considerable attention in recent years. Monitoring of EDC and PPCP residues has been conducted in raw and treated sewage, surface waters, ground waters, and drinking waters. Recent research has been aimed at improving analytical methods and furthering knowledge of fate and transport processes, environmental risks, source reduction, and risk management including treatment of EDC and PPCP contaminants. This paper provides an overview of the topic and regulatory issues pertaining to our understanding and managing of EDCs. In addition, this paper provides discussion on emerging concerns regarding PPCPs in the environment. Completed research is described pertaining to development of analytical methods, occurrence of EDCs and PPCPs in waters of southeastern Louisiana USA and Ontario Canada, assessment of drinking water treatment processes, and experimental results regarding the formation of chlorinated naproxen byproducts and impact of these byproducts on a simulated biofilm system. And finally, EDCs and PPCPs are described from an industry perspective.

Across the United States, there is a rapidly growing awareness of the occurrence and the toxicological impacts of natural and synthetic trace compounds, known as emerging Contaminants(ECs) in the environment. Wastewater treatment plants (WWTPs) have been identified as a key collection point for ECs in the water cycle and potentially an ideal location at which to treat to remove them, thereby mitigating their release into the environment. Little is known about the nature, variability, transport and fate of ECs in typical wastewaters and treatment facilities in the United States. Furthermore few studies have been performed to monitor or understand the capability of conventional or innovative wastewater treatment processes to remove or reduce the concentrations of a wide variety of ECs at wastewater facilities. This study was designed to provide baseline information on this topic. Wastewaters appear to contain a wide range of ECs. Over 55 of the 63 target contaminants were detected in the five different wastewaters examined during the course of this study, 44 of them frequently. The median cumulative concentrations of EC in the wastewaters ranged from between 120 μg/L to just over 500 μg/L. The raw wastewater characteristics were not as variable as anticipated. Conventional wastewater treatment processes were effective in removing significant amounts of the ECs. Results indicated that the type of technology operated and the mode of operation both had an impact on the removal capability of the plants. Over half of the frequently detected ECs were reduced by 95 percent or more in samples collected at Plants which operated an activated sludge process. Less than 10 percent of the ECs were reduced by 95 percent or more at Plant D, which uses a trickling filter treatment process. Furthermore, focused pilot studies indicated that increased removals of ECs were closely associated with increased SRTs in the activated sludge process. The most significant impact of SRT appeared to occur as the sludge age increased above 5 days. While removals continued to improve as the SRT increased above 10 days the benefits were less marked.

We conducted preliminary biotransformation experiments utilizing LC-MS/MS analysis of supernatant collected during batch cultivation of monoculture of Nitrosomonas europaea with carbamazepine (CBZ), iopromide (IOP) and trimethoprim (TMP), three environmentally relevant pharmaceuticals and personal care products (PPCPs). CBZ and TMP were not transformed during batch incubation with N. europaea. IOP results indicated significant removal (65–70%) of the parent compound over 28.5 days of cultivation. Four metabolites designated IM1 (237 m/z), TM2 (279 m/z), IM3 (219 m/z) and IM4 (239 m/z) were observed over the course of the experiment with IM1 and IM2 being predominant up to 19.5 days. Between 19.5 days and 28.5 days, IM1 dropped below detection while IM3 and IM4 were detected along with IM2. Sorption data indicated that the fate of CBZ and IOP is not primarily governed by sorption to biomass. Future experiments will provide further information regarding the fate of these PPCPs under physiological conditions typical of treatment plants, while also characterizing metabolite formation.

Occurrence of pharmaceutically active compounds (PACs), such as estrogen hormones in environmental systems, has gained widespread attention due to their adverse effects on the ecology and possibly humans. In our study, surface water was sampled from 21 water streams located in Eastern Pennsylvania. The presence of several estrogen hormones compounds was examined. All streams sampled showed the presence of at least one hormone compound. Estrone and estriol were detected in more than 80% of the sampling sites. The most frequently detected hormone was estrone, with concentrations ranging from 0.6 to 2.6 ng/L. Estriol was the hormone with the highest recorded concentration of 19.7 ng/L. The concentration of ethinyl estradiol detected in this study was about 30 times greater than the 0.1 ng/L reported to cause feminization of fish. One important pollution source of these pharmaceutical compounds is the effluent and sludge from wastewater treatment plants. Wastewater was collected from different points at two municipal wastewater treatment plants (WWTPs) and analyzed for estrogens. The effluent of the wastewater is directly discharged into the surface water. 17β-estradiol, 17α-dihydroequilin, 17α-ethinyl estradiol, estriol and estrone were found in the sampled effluent wastewaters. The concentration of the detected estrogen hormones ranged from 0.5 to 50 ng/L. Estrone was detected in the effluent of all two WWTPs. The occurrence of estrogens in the final dewatered sludge from municipal WWTP was also investigated. After being disposed or land applied as agricultural fertilizer, the sludge could represent a pollution source due to the leaching of pharmaceutical compounds into the water systems. The leaching process was simulated in the laboratory by mixing the sludge with clean water. The concentrations of leached hormones in the aqueous phase were then examined. Another important pollution pathway of these pharmaceutical compounds is from the agricultural animal wastes, which are typically land applied. In this study, cow manure and chicken manure were sampled for analysis of estrogen hormones. 17α-estradiol, 17β-estradiol, 17α-dihydroequilin and estrone were detected in the cow manure with concentrations ranging from 6.2 to 27.4 ng/g dry solid. After mixing with water, about 18% to 48% of estrogens entered the aqueous phase. 17α-estradiol, 17β-estradiol and estrone were detected in chicken manure with concentrations ranging from 44 to 150 ng/g dry solid. About 10 to 100 % leaching was observed. Used compost was also sampled and analyzed, to determine the occurrence and leaching properties of estrogen hormones.

Leaching behavior of estrone (E1), 17β-estradiol (E2), octylphenol, and nonylphenol were studied in a tropical soil that is enriched with metal oxides. Due to intense weathering, silica content is depleted in these soils. The adsorption behavior of these chemicals was studied as a function of solution pH, ionic strength, and dissolved organic content. Leaching experiments were conducted to examine the transport of these chemicals in packed columns. Results indicate that these compounds strongly adsorb to the tropical soils and it is very difficult to obtain breakthroughs even at high influent concentrations.

Increasing sensitivity of new analytical methods has enabled the detection of certain endocrine disrupting chemicals (EDCs) in drinking water systems. EDCs in raw water entering drinking water treatment plants can arise from many potential sources, including municipal wastewater treatment plant effluent, industrial discharges, agricultural activities, etc. Questions remain about the potential health effects of long-term, low-dose exposures to EDCs via potable water supplies. Of particular concern are potential consequences to sensitive population groups, such as pregnant women and children. We present preliminary data arising from our work on assessing the potential health risks of these chemicals and establishing target concentrations for water treatment. Specifically, we focus on the selection of chemicals of concern (COC) for this project. EDCs were selected as COC for this project on the basis of the following five criteria. (1) Status as an EDC. A literature review was conducted to collect evidence that certain chemicals can be classified as EDCs. Emphasis was placed on chemicals that have produced an adverse effect mediated through the endocrine system in at least one in vivo test system with a laboratory animal that serves as a surrogate for humans or that have been reported to produce an endocrine effect in humans. (2) Likelihood of exposure through drinking water. To assess occurrence in drinking water, monitoring for target chemicals is underway at several drinking water utilities nationwide. A literature search revealed additional occurrence data for source water, raw water, and drinking water, as well as information that can be used to predict the removal of EDCs through drinking water treatment processes. (3) Potential to cause adverse health effects. Severity of effects, potency, and pharmacokinetics (e.g., half-life, bioaccumulation) were considered. (4) Endocrine mode of action. Only those chemicals that act through the so-called "EAT" modes of action (Estrogenic (or anti-estrogenic), Androgenic (or anti-androgenic), and Thyroid-related) were considered. (5) Interest in specific contaminants. The Project Advisory Committee (PAC) and participating utilities were asked to identify EDCs that they believe are potential concerns. EDCs that appear to be the subject of interest among the public and the scientific community also were considered. For selected EDCs, animal and human clinical toxicity data are being examined to establish threshold exposure levels of concern, particularly focusing on the potential for reproductive and developmental effects and effects on endocrine function. The results of this project will provide information to determine whether consumption of EDCs in municipal drinking water poses a public health risk; which chemicals likely present the most significant risks, and which treatment systems most effectively reduce target chemical concentrations.

Endocrine disrupting compounds (EDCs) are substances that influence the endocrine system in living organisms. They include natural hormones, medicinal drugs, chemical compounds in industry, and pesticides in agriculture. The substances may be present in water and wastewater, soil and sediments, or airborne. Our research is focused on the estrogenic EDCs, i.e. substances which mimic the natural hormone estrogen produced by the body, and their occurrence and fate in the context of wastewater management. The primary contributors to estrogenic activity wastewater are 17β-estradiol, estrone, and 17α-ethinylestradiol. We are interested in readily detecting and quantifying this estrogenic activity as a first step in the daily management and reduction of estrogenic EDCs in wastewater before discharge into the environment with effluent and biosolids. We report progress on a fluorescence assay for the presence of estrogenic activity in water samples using a living estrogen-sensitive yeast cell strain, and on a study of responses of living yeast cells to estrogen and alkylphenol exposure using synchrotron radiation-based Fourier Transform infrared spectromicroscopy (SR-FTIR). The fluorescent response of the yeast allows for rapid sample screening, and the SR-FTIR infrared spectrum is a measure of the overall in vivo yeast biochemical response to the sample.

A series of experiments investigating the removal of trace endocrine disrupting chemicals (EDCs) and Pharmaceuticals were conducted at bench-, pilot-, and full-scale. These investigations were part of an AwwaRF funded project to investigate a plethora of water treatment processes for the removal of these emerging contaminants (AwwaRF Project #2758). This presentation will speak to oxidative disinfection processes, and their role in the removal of microcontaminants.

Wastewater reclamation and reuse is imperative in water-starved areas such as the southwestern United States. In the Tucson Active Management Area, a geographic region defined for the purpose of groundwater management, the total demand for water already exceeds the available water supply, which consists of renewable ground water and the regional entitlement to Central Arizona Project water. Thus, the regional demand cannot be satisfied without resorting to groundwater mining unless water is reclaimed for local beneficial use. Less certain are the acceptable uses for reclaimed water and the nature of use-dependent treatments or water quality requirements that will protect human and ecological health. Disruption of thyroid-mediated actions is among the possible risks from chronic exposure to environmental contaminants. Although numerous Pharmaceuticals and personal care products have been detected in surface waters of the United States that are influenced by wastewater effluent, only a few such compounds are present at concentrations that produce recognizable adverse effects in the environment. Endocrine disrupting compounds (EDCs) are generally of greater concern in this context than other trace contaminants because of the very low concentrations at which hormones induce physiological responses. Anthropogenic chemicals can disrupt nuclear thyroid hormone signaling without affecting circulating levels of thyroid hormone. Accordingly, we sought to develop a sensitive nuclear-based assay system in order to evaluate environmental samples. The use of a Luciferase-based reporter assay is commonly used to detect transcriptional activity. We evaluated a luciferase-reporter construct and the human thyroid receptor β (TR-β) construct for sensitivity in the human hepatoma cell line, (Hep G2). The transfected cells were exposed to T3 at concentrations in the range 10-6 to 10-11M in order to establish a lower thyroid hormone detection limit and EC50 for the new bioassay procedure. The assay was then applied to environmental samples containing organics concentrated from final effluent derived from a conventional secondary wastewater treatment plant. The effluent samples activated thyroid receptor-mediated transcription.

In a previous study, the authors determined ammonia (NH₃) emission rates varied from 200–300 g/d/AU (AU-animal unit). In this study, the fate of the released ammonia from the poultry houses was evaluated. The poultry house NH₃ emission rate at 0.001 g/sec is significant. The study included NH₃ emission rates of 0.001 to 1.0 g/sec at a typical Delaware poultry house operation. The poultry house' forced ventilation system air velocity of 2.0 m/sec and air exchange requirements were reviewed. The USEPA approved and promulgated SCREEN3 air model was set-up and run on the estimated NH₃ emissions from a typical poultry house. The maximum downwind concentration(s) (MDC) of NH₃ did not meet the Delaware air quality criteria of MDC to be equal to or less than 1/100^th TLV. SCREEN3 model results indicated the requirement of proper NH₃ emission control of poultry house operations and an advanced review of the poultry house air emissions.

A landmark agreement between the USEPA and the State of Florida and the Tampa Electric Company (TEC) featured substantial reductions in SO₂, NOx, and PM emissions from two coal-fired power plants in Tampa, Hillsborough County, FL. The TEC committed to re-powering the FJ Gannon power plant from coal to natural gas, re-naming the plant to the Bayside power plant; to adding SO₂ scrubbers on two older boiler units at their Big Bend power plant; and to the installation of NOx controls on the Big Bend power plant. Between 1997 and 2005, an annual average decrease of 10 μg m^–3 in ambient air SO₂ concentrations at an urban monitoring site in Hillsborough County, Florida, accompanied the removal by TEC of 140,000 metric tons of SO₂ from the emissions inventory. Over this period, the observed change in annual average NOx concentrations at one urban monitor was 5 μg m^–3, which was reasonably consistent with the SO₂ reduction rate (e.g., 1 μg m^–3 for every 14,000 metric tons of SO₂ removed). Downward temporal trends at urban monitors unadjusted for seasonal dependencies, however, were statistically significant for SO₂ but not for NOx concentrations.

Wastewater treatment facilities, both industrial and municipal, are often subject to state air permitting and annual emission reporting requirements. Additionally, Federal and state regulatory agencies scrutinize emissions to the air from wastewater treatment facilities. In each of these conditions, air permitting, emission reporting, or responding to regulatory agency requests for information, quantification of pollutant emissions to the air is required. Emission sources of concern at wastewater treatment facilities typically include gas combustion (e.g. digester gas flares or engines), material handling, and fugitive emissions from wastewater treatment operations. Quantification of emissions from combustion and material handling processes is relatively straightforward; emission calculations are typically performed using published emission factors, equipment manufacturer's guarantees, or facility specific stack testing results. Quantification of emissions from wastewater treatment units is more complex, with variability in influent composition and flow rate along with a wide variety of different treatment units each with its own emission characteristics. Typically, characterization of influent water composition and treatment unit parameters must be used with an emision model to quantify emissions from wastewater treatment units. There are several choices for modeling emissions from wastewater treatment units. Some of the more common choices include the WATER9 model, the TOXCHEM model, equations found in AP-42, or Pooled Emission Estimation Program (PEEP) emission factors. This paper provides a description of these models, a discussion of how they can be used, and considerations for model selection.

Gases and odors are generated from livestock and poultry manure decomposition shortly after it is produced, during storage and treatment and during land application. Odors originating from livestock operations may contain many different chemical compounds. Odors are characterized by concentration intensity, persistence, hedonic tone and character. Odor concentrations are measured by an olfactometer and a panel of trained assessors and usually reported as odor units. Atmospheric dispersion models are used to model odors from livestock operations. Most of the models that have been used are Gaussian plume dispersion models and include ISCST3, AUSPLUME, AERMOD, STINK, AODN, INPUFF2 and CALPUFF. A number of different modeling approaches have been used to estimate ammonia emissions from livestock operations. The emission models can be classified as mechanistic models, empirical models, mass balance models, inverse dispersion models and process based models.

Estuarine dynamics play a critical role in the transport and fate of bacteria, including those of importance to human health. In this work, the Neuse River Estuary (NRE) in eastern North Carolina was observed through a two-year period to detect links between environmental attributes (e.g., salinity, suspensions) and the transport of two groups of bacteria: fecal indicators and Vibrio sp. (VIB). These bacterial groups differ in their sources and ability to grow once in the environment. Indicators, in this case E. coli (EC) and Enterococcus sp. (ENT), are presumed to be introduced in fecal contamination and simply decay once in the estuary. Large fractions of both indicators have been found attached to particles. On the other hand, VEB are native to the NRE and highly dependent on salinity and temperature. The potential impact of estuarine disturbance on bacterial transport was exemplified by the passage of Hurricane Ophelia in September 2005. The NRE experienced a significant storm surge of salt water, followed by a large runoff input. Water samples and sediment cores were collected, including samples from an in-situ sampler during the storm. Patterns were seen in the salinity and suspension that defined periods of surge, resuspension and runoff during the storm. ENT appeared to have two sources (resuspension and runoff), while EC appeared late in the storm, supporting the conclusion that runoff was its primary source. VTB showed more variability, with high concentrations prior to the storm dissipated, then replaced by the receding storm surge. Sediment ENT concentrations in the sediment bed remained fairly constant throughout the storm period, while EC and VIB both significantly increased following Ophelia. The sediment bed represents an environment that may harbor these bacterial populations through periods of harsh conditions in shallow estuaries (low temperature, salinity changes, nutrient limits, sunlight). The results of this study reinforce the importance of high-frequency sampling and coring of surface sediments to complement water quality monitoring, especially for efforts targeting bacterial groups with potential human health impacts.

In 2001, following a change in disinfection agent in anticipation of the EPA Disinfection Byproduct Rule, lead levels began rising in drinking water in Washington, DC, and in 2002 the DC Water and Sewer Authority was found to have exceeded the EPA lead action level, requiring compliance with a series of measures under the Lead and Copper Rule. In 2004, the issue became a public concern, drawing considerable media attention. The problem was eventually resolved through the application of orthophosphate but while it played out the utility was forced to respond to a novel public health issue with constrained risk management options. In order to evaluate the public health implications of the exceedance, the DC Department of Health expanded the scope of its monitoring programs for blood lead levels in children. Children from 6 months to 6 years of age constituted 2,342 of those tested; 65 had blood lead levels above 10 μg/dL (the "level of concern" defined by the Centers for Disease Control and Prevention), the highest with a level of 68 μg/dL. The majority were attributed to lead paint found in houses. There was no correlation in children with documented paired values between blood lead and lead in water. This study cannot be used to correlate lead in drinking water with blood lead levels directly because it is based on an ecological rather than individualized exposure assessment, the protocol for measuring lead is based on regulatory requirements rather than intake, numerous interventions were introduced to mitigate the effect, and the period of exposure spanned approximately two years rather than lifetimes for adults. We examine lessons learned, including issues of simultaneous compliance, public health risk management, and risk communication.

Health scientists and epidemiologists rely on groundwater-flow and fate-and-transport models to reconstruct historical exposures to groundwater contaminants when conducting environmental health studies. One of the key factors in determining human exposure to contaminants is reliable estimates of historical contaminants arrival times at water-supply wells and at the associated water distribution system (WDS), including the water treatment plant (WTP). One uncertain variable that may affect the arrival time is the scheduling, or on/off cycling, of water-supply wells feeding the WDS. Uncertainty related to pump scheduling and thus the arrival time can significantly impact the related epidemiologic study. In this paper, a procedure is described that combines groundwater simulation models and an optimization method to evaluate the change in the Maximum Contaminant Level (MCL, 5 ppb for tetrachloroethylene (PCE)) arrival time at the WTP. The procedure was applied to an epidemiologic study currently being conducted at U.S. Marine Corps Base Camp Lejeune, North Carolina.

Stormwater and combined sewer overflows (CSOs) are two of the major sources of water pollution in the greater Milwaukee area. In response to charges that combined sewer overflows were the primary cause of poor water quality at local beaches, the Milwaukee Metropolitan Sewerage District (MMSD) with the assistance of Department of Civil Engineering and Mechanics, University of Wisconsin-Milwaukee initiated an investigation of how pollutant concentrations from combined sewer overflows compared to concentrations from stormwater. Although much historical data exists to characterize combined sewer overflows, less data is available for stormwater. Therefore, a stormwater runoff sampling program commenced in 2000 for 33 parameters at 18 monitoring sites representing a variety of land uses. The data was analyzed to identify spatial and temporal trends, seasonal variability, and the relationship between first and second flush concentrations. Total pollutant concentrations from stormwater were compared to concentrations from combined sewer overflows. This comparison showed that many pollutants in stormwater were at a higher concentration than pollutants in combined sewer overflows. Stormwater runoff events occur much more frequently than combined sewer overflows. Based on this study, stormwater, not combined sewer overflow, is the dominant source of pollutants for local waterways.

Health scientists and epidemiologists rely on groundwater flow and fate and transport models for reconstructing historical exposures to contaminants such as tetrachloroethylene (PCE) when conducting environmental health studies. Of concern to epidemiologists is the reliability of historical estimates of the spatial and temporal distribution of contaminants used in determining exposures. Thus, evaluation of uncertainty and variability of hydraulic and transport parameters should be assessed as part of the overall exposure assessment process. In a health study of historical exposure to PCE-contaminated drinking water at U.S. Marine Corps Base Camp Lejeune, North Carolina, (1) uncertainty analyses were conducted; (2) probability density functions were generated for hydraulic and transport parameters using Monte Carlo and Gaussian sequential simulation; and (3) the related probabilistic analyses were incorporated into the MODFLOW and MT3DMS simulation codes.

In this research, the sorption and transport of MS-2 in saturated sediments under the impacts of salinity and soluble organic matter (SOM) are studied through one-dimensional column experiments. The experiments are conducted with the prepared fine sand (d₅₀=0.13mm) from industry and the mixture of the sand and field soil (d₅₀=0.16mm) obtained from Bayou Segnette State Park, Louisiana. The controlled conditions in all experiments include constant flow rates (0.2 mm/s), neutral condition (pH=7.0±0.5), and constant temperature (25±0.2°C). Bromide is adopted as the conservative tracer to evaluate the retardation factors of MS-2 in the column. In the sorption and transport experiment with MS-2 mixing with nanopure water, the MS-2 showed slight adsorption effect onto sediments. When SOM was added, no attenuating effect on MS-2 adsorption was observed because of MS-2's already weak adsorption in nanopure water. The MS-2 with salinity experiment showed dramatically enhanced adsorption effect in the sand column. It can be explained that the salinity compressed double layers, thereby increasing attachment rates. However, no effect was observed in the sand/soil mixture column, counteraction by organic matter from the soil is the main reason.

Coal gasification, cleaning of the synthesis gas (syngas), and combustion of the clean syngas is currently the upcoming IGCC (Integrated Gasification Combined Cycle) method in the thermal power production and control of several air contaminants and possibly the greenhouse gases. A good number of patented feed-gasifiers are commercially available. Once coal or other feed is gasified, the elemental sulfur is removed from syngas and, then it is possible to remove the carbon-dioxide (a greenhouse gas) as required by the upcoming local, state, and federal environmental regulations. Currently, the syngas with the carbon-dioxide is fired in the stationary combustion turbines (CTs) to produce power. IGCC process is, currently, the preferred choice over conventional thermal power production in regard to cleanup of fuel and significantly reduced contaminant emissions. The air permitting requirements include the review of: feed preparation and PM emissions; feed gasification and contaminant emissions; elemental sulfur recovery and SO₂ emissions; options for carbon-dioxide recovery; syngas characteristics for combustion; CT design and combustion mechanisms; air contaminant emissions of CT; controlled CT emissions of nitrogen-oxides and carbon-monoxide gases using the SCR and oxidation catalysts, respectively; and, emission of volatile organic compounds (VOCs), and hazardous air pollutants (HAPs). However, the IGCC processes are being rigorously reviewed for the system integration and reliability, and significant reduction of air contaminant emissions (including the greenhouse gases). This paper included a review of IGCC air contaminant emission rates, and various applicable regulatory requirements, such as NSR (New Source Review), NSPS (New Source Performance Standards), and MACT (maximum achievable control technology). The IGCC facility's NO_X, CO, SO₂, PM, VOCs, and HAPs emission rates would be significantly low. Thus, effective, construction and installation, and operation air permits would be necessary for IGCC facilities.

An effective environmental permitting of industrial facilities is necessary. Owner or operator's background information is a necessary part of review of environmental permitting of an industrial facility. The manufacturing processes, fuel-combustion operations, and water usage and discharge, waste generation and disposal, and material storage operations have applicable environmental requirements. The environmental permits would list all necessary requirements. Acquisition of all applicable environmental permits is a partial fulfillment. Complete environmental compliance would depend on compliance with permit(s) contaminant emission or discharge and operational limitations, monitoring and testing requirements, record keeping and reporting requirements.

Many municipal wastewater treatment plants are finding themselves subject to increasingly complex air quality regulations. Relatively small reciprocating engines burning digester gas trigger the need for state or federal air construction permits. New digester gas fired boilers larger than 10 million BTU per hour are likely subject to Federal New Source Performance Standards (NSPS). Emissions of volatile hazardous air pollutants from wastewater treatment and solids handling operations may be subject to the Federal National Emission Standards for Hazardous Air Pollutants (NESHAP) for Publicly Owned Treatment Works. Title V operating permits (also known as "Part 70" permits) are increasing the recordkeeping and reporting obligations for wastewater treatment plants. In this paper we present some regulatory alternatives available to wastewater treatment plants to help minimize their air permitting requirements. We show exemption levels for several air permitting and regulatory programs. In addition, we present opportunities available to wastewater treatment plants to receive benefits related to their air emissions. For example, electricity generated from the combustion of digester gas or biosolids may be considered a "renewable resource". Utilities in several states are either required or encouraged to provide a portion of their electrical production from renewable resources which provides treatment plants with a financial benefit opportunity.

Synthetic organic polymers are typically used in water treatment to coagulate colloids and enhance the performance of sedimentation and filtration processes. This research investigates polyacrylamide (PAM) application for use in unlined conveyance channels to decrease water infiltration rates. Column studies were conducted with well-sorted sand to determine the infiltration effects of PAM dosage and to evaluate possible seepage reduction mechanisms. Results showed hydraulic conductivity reduction increases with increased PAM concentration, with a maximum hydraulic conductivity reduction of 95% at a 150 ppm PAM dose. In addition, results indicated that a polymer adsorption mechanism was responsible for the hydraulic conductivity reduction. With adsorption, the polymer most likely interacted with the porous media, creating a coating layer around the sand particles. Long term column tests showed that with adsorption, hydraulic conductivity returned to background values once polymer application ceased. An adsorption isotherm test confirmed that PAM was capable of adsorbing to the media. Isotherm data was described using the Freundlich equation with n = 0.56 and a distribution coefficient (K_d) of 7.7 L/mg.

The 2004 and 2005 hurricane seasons inflicted tremendous damage throughout the southern United States. After many years of below normal storm seasons, the most recent two storm seasons brought with them record numbers of storms and the most costly natural disaster in our country's history. Hurricanes are not the only reasons Disaster Debris Management is implemented. Recent world catastrophes, both by nature and man, such as the 2005 Tsunami that ravaged Indonesia, terrorist attacks in New York and Washington D.C., earthquakes in South America, and random blizzards in Buffalo, NY in 2006 exposed a weakness in accurate data collection during disasters. The authors of this paper have personally been involved in disaster remediation for the past seven years focused primarily on debris management activities. In years past, federally-mandated debris management processes consisted of a largely manual process of load ticket administration, distribution, and summarization. The use of the traditional paper load ticket in debris management is fraught with problems related to the very nature of the paper ticket. The ticket relies on accurate and legible recording of information. There is no way to control or verify the information recorded until it is manually reviewed after the fact. Due to the enormous volume of tickets produced in a typical event, any sort of status reporting and billing activity generally lags well behind the work being performed in the field. This is exacerbated by the delay in collecting, entering, and analyzing the data contained on the paper ticket. Archival and retrieval of the paper tickets also presents a logistical challenge. A database of electronically-managed tickets and recorded data entry fields can greatly improve data quality and timeliness while reducing the logistical challenges of finding and reporting from paper tickets. However, one of the primary limitations in electronically collecting and reporting debris management information after a catastrophic hurricane event is the potential lack of traditional electronic or wireless network to transfer information in a timely and reliable manner.

As urbanization increases, solid waste facility sites once considered remote are now located in areas increasingly ripe for development or re-development. Consequently, we see lands adjacent to solid waste facilities being considered for developments such as residential communities and commercial and industrial projects. The objective of this research is to develop methodology to gather scientific and quantifiable support for set backs and buffer zones as a function of landfill operations. To date, volatile organic compound and noise measurement data have been collected and are being analyzed. Future work includes analysis of dust measurements and a litter study. Bird impacts will be evaluated based on litter study by identifying typical debris attractive to birds.

This paper investigates groundwater system characterization problem, in this inverse problem the contaminant signals at monitoring wells are recorded to recreate the pollution profiles. In this study, simulation-optimization approach is a technique utilized to solve inverse problems by formulating them as an optimization model, where evolutionary algorithms are used to perform the search. In this approach, the PDE groundwater transport simulation model (simulation model) is solved iteratively during the evolutionary search, which in general can be computationally expensive. To overcome this limitation, high performance computing and grid computing are used to improve the simulation model efficiency. The parallel PDE groundwater transport simulation model is then coupled with an evolutionary computation search procedure to solve two instances of groundwater inverse problems. The results demonstrate the performance of the grid-enabled simulation-optimization approach in terms of solution quality and computational performance.

This paper presents ongoing research on building an interactive and multi-objective framework to solve the groundwater inverse problem. Our research has shown that the inherent instability and non-uniqueness of this problem can be improved by incorporating expert knowledge about the hydro-geology of the site. The interactive multi-objective genetic algorithm (IMOGA) considers user preference (for different transmissivity fields) as an additional objective along with quantitative calibration measures, converging to a set of Pareto optimal solutions representing the best trade-off among all (qualitative as well as quantitative) objectives. An important part of groundwater inversion is assessing parameter uncertainty and its effect upon model predictions. To assess the uncertainty in prediction we a multi-level sampling approach is used that incorporates uncertainty in both large-scale trends and the small-scale stochastic variability. The large-scale uncertainty is modeled using a Bayesian approach where both calibration error and a prior transmissivity field (as specified by the expert through the interactive rankings of the IMOGA) are considered. A geostatistical approach is adopted for the small-scale uncertainty, which is considered to be unconditional and auto-correlated with a specified covariance structure. The prediction model is run using all simulated fields to get the distribution of predictions. This methodology is being applied to a field-scale case study based on the Waste Isolation Pilot Plant (WIPP) situated in Carlsbad, New Mexico. This work is still in progress and results will be presented at the EWRI conference.

A number of different pipe failure prediction models have been developed in the past to actively manage the sewer systems. Here, a novel methodology for developing mathematical models for the prediction of sewer system failures (i.e. number of collapses and blockages over some fixed time period) as a function of different potential explanatory factors (e.g. pipe material, diameter, age, soli type, traffic load, etc.) is presented. The methodology is based on the application of recently developed Evolutionary Polynomial Regression (EPR) technique to a group of (rather than several individual) sewer systems. The methodology is tested and verified on a real-life case study involving two UK sewer systems. The results obtained clearly demonstrate that, when compared to the two individual models, in the case of a grouped pipe failure prediction model local effects are neglected in favour of a more general description of the underlying deterioration phenomenon. As a consequence, even though the grouped pipe failure prediction model has reduced accuracy (i.e. reduced model fit) it is less prone to data over-fitting phenomenon.

Surveillance system for an aquatic environment is an important aspect of water quality monitoring in lakes and oceans. It is well known that long-term surveillance of aquatic environments is a costly endeavor, thus a sound strategy is necessary to select the best locations of monitoring stations to improve the performance of a monitoring system. This can be accomplished by optimizing the locations of a sensor network with respect to the hydraulic and fate and transport characteristics of the surface water system. It is expected that such an approach will improve the effectiveness of the monitoring system and also reduce the overall cost. Since the hydrodynamics and the contaminant migration pathways in a surface water environment are complex, the optimal solution to this problem is complex. To solve this problem in a simplified form, a 2-dimensional hydrodynamic simulation model is developed using a finite element method. The best sensor locations are selected to minimize detection time of the contaminant presence. Due to nonlinear nature of the model Genetic algorithm (GA) is used in optimization formulation to select the best sensor network. Furthermore, this computation processes require a significant amount of computational time, thus parallel computing is adopted to reduce computation time.

This study tackles the problem of modeling of the complex, non-linear, and dynamic runoff process. To overcome local optima and network architecture design problems of ANN to make runoff forecasting of catchment more accurate and fast, an hybrid intelligent genetic annealing neural network (IHGANN ) algorithms is established by recombining and improving artificial neural network(ANN) and genetic algorithm (GA). The typical approach can be regarded as a hybrid evolution and learning system which can combine the strength of back propagation (BP) in weight learning and GA's capability of global searching the architecture space. However, the standard genetic algorithm(SGA) adopts constant crossover probability as well as invariable mutation probability. It has such disadvantages as premature convergence, low convergence speed and low robustness. Common adaptation of parameters and operators for SGA is hard to obtain high-quality solution, though it promotes the convergence speed. To address this problem, the IHGANN algorithm applies the simulated annealing algorithm to increase the fitness properly, the self adaptation technology to adjust the value of crossover probability and mutation probability. Meanwhile, a fitness normalization formula is introduced and it always gets a positive value. The new formula can guide the population to a proper direction and increase the press for selection of individuals. The similarity is defined to increase the varieties of individuals without increasing the size of population, thus solving the problem of local optimized solution. Moreover, IHGANN's real encoding scheme allows for a flexible and less restricted formulation of the fitness function and makes fitness computation fast and efficient. This makes it feasible to use larger population sizes and allows IHGANN to have a relatively wide search coverage of the architecture space. In order to verify the feasibility and validity of the IHGANN, we give an example for some watershed located on the Jinsajiang river basin, Yunan province, southwest China and carry out serial simulation experiments by using BP, the IHGANN separately. The simulations showed that problems faced by both back propagation algorithm and standard genetic algorithm were overcame by IHGANN. Compared with BP, the IHGNN has faster convergence speed and higher robustness. Lastly, an dynamic intelligent interactive interface of the runoff forecasting system is developed by using the VC.net programming language.

The combined use of models, together with optimisation algorithms (OAs), has evolved as a crucial element in the decision making process for groundwater management. Typically, the OA iteratively runs the model, evaluates the output with respect to an objective function and, finally, identifies an optimal solution. This procedure may afford hundreds to thousands of model runs, particularly for high dimensional, non-linear and non-convex optimisation problems. Our research focuses on tactics to minimize the required number of simulations and thus the computational time, without compromising the performance of the OA. Otherwise CPU demanding models will hardly be applicable within a reasonable timeframe. By utilizing a modern variant of evolutionary algorithms, the so-called evolution strategies with covariance matrix adaptation (CMA-ES), we demonstrated that there is a huge potential to save iterations compared to alternative, more common OAs. In this presentation, we discuss prominent characteristics of problems involving more than one realization of reality, focusing on the stacking approach, a common method to account for descriptive uncertainty. Here, during optimization, multiple realizations are considered simultaneously. A robust managerial solution has to succeed in all or at least most of the realizations. A practical consequence is that the number of realizations multiplies the computational time. Nevertheless, the results of our study are evidence for only a small fraction of the stack (the critical realizations) controlling the identification of the optimal solution. This observation encouraged us to develop a procedure which is based on dynamic stack ordering and to ignore uncritical solutions.

An interactive educational module has been developed to introduce graduate-level students to genetic algorithms and their applications in surface water systems analysis. The module includes a user-friendly graphical user interface that is used to select genetic algorithm heuristics and parameters and explore their effects on the analysis of an irrigation canal network management problem. The simulation model for the canal network is an unsteady flow model that predicts the response of the water levels in the network to changes in boundary conditions and internal sluice gate operations, as well as irrigation requirements of different crops in the areas served by the network. This model is incorporated into a genetic algorithm-based search framework to find efficient strategies for scheduling gate operations and boundary conditions that address a certain objective (minimizing the amount of water consumed) and constraints (such as preventing flooding and water shortages, maintaining stability of gates, and maintaining adequate water levels at water supply intakes) over a period of time. This module has been developed primarily for use in graduate level water resources systems analysis courses, and is intended to help students visualize and understand the effects of different GA operators, parameters and constraint-handling techniques on the search process and the solution quality. This paper describes the capabilities of this educational module, and demonstrates ways that it can be implemented in a surface water systems analysis course.

Handling constraints in Evolutionary Algorithms (EAs) can be challenging, especially for highly constrained, complex optimization problems. Because constraints are not handled directly in an EA, heuristics must be carefully designed and applied to guide the search toward feasible, good-performing solutions. A common way to handle constraints in EAs is to use penalty functions. These penalty functions can have various formulations, and often require time-consuming fine-tuning of the penalty parameters to effectively search for feasible solutions with good objective function values. This paper investigates the performance of various constraint-handling techniques applied to an EA-based irrigation canal network management problem. The problem involves determining efficient network operations that minimize the water consumed while preventing problems such as water shortage and flooding. The case study is based upon a complex large-scale irrigation network in Egypt. The constraint-handling methods investigated include three penalty functions. The associated fine-tuning parameters for each constraint-handling method are varied to investigate the sensitivity of the solution quality (feasibility and objective function value) to these parameters. The solution quality and its sensitivity to the constraint-handling parameters are compared for the constraint-handling methods. This comparison is intended to help provide guidelines for better performing penalty function methods for an EA-based irrigation canal network management problem that can be successfully implemented without excessive fine-tuning requirements.

Since January 2003, the U.S. Army Engineer Research and Development Center has been developing a parallel watershed code, pWASH123D, and its graphical user interface in the Department of Defense Groundwater Modeling System in collaboration with Brigham Young University. To date, pWASH123D has a complete suite of water flow simulations in a watershed system that can be conceptualized as a combination of one-dimensional (1-D) channel network, 2-D overland regimes, and 3-D subsurface media. This paper presents the outcome of a performance study on the parallel algorithms currently employed in pWASH123D. The experimental area includes a 570-square-mile domain covering most of the land south of the Tamiami Train in South Florida and north of the Gulf of Mexico, Florida Bay, and Biscayne Bay. This area is discretized to three mesh resolutions—coarse, medium, and fine meshes—to identify the performance bottleneck. Problems are designed to investigate the parallel strategy for the 1-D component. Major findings from the study are presented in this paper.

A command-line program was created that enables a backwater model to be calculated directly from a set of GIS cross-sections. The program furthermore generates a GIS representation of the floodplain, a simple set of elevation plots of the cross-sections and water surface in PDF format, and a set of GIS cross-sections with the calculated hydraulic parameters attached as attributes. The program does not fully provide the functionality of a hydraulic model such as HEC-RAS. However, it can generate a reasonably accurate floodplain very quickly, typically in about ten seconds once the input files (centerline and topography) have been created. Cross-sections can be added, moved or realigned in GIS and the script will ascertain the sequence of the cross-sections and the reach lengths. The program is also robust and will almost always generate a floodplain. An optional feature also generates a shapefile of evenly spaced cross-sections based on the stream centerline using either of two algorithms, although some cross-sections may be later adjusted manually. The rapid delineation of the floodplain using this technique is useful for the approximate delineation of floodplains and fulfills all requirements for FEMA submittal as an approximate study. Although many simplifying assumptions are made, the script computes a backwater analysis (equivalent to the standard-step approach), and therefore is more accurate than any delineation based on normal depth approximations. Furthermore, the program is useful in rapidly obtaining reasonable alignments of the stream centerline and cross-sections and an accurate estimate of the floodplain limits even when a detailed hydraulic model will be created later.

Structural BMPs like stormwater basins (detention and retention basins), wetlands, filter strips and grassland swales are extensively used as stormwater runoff controls. BMPs are often designed for peak flow reduction or pollution control or can be considered for dual purpose in that they provide both water quality and quantity benefits by relying upon storage allocation and key mechanisms of setting filtration, sorption, biodegradation and evapotranspiration. In spite of previous studies, there exists neither a methodology nor a generalized model for selecting, placing, and sizing BMP combinations that cost-effectively promotes achievement of treatment goals at larger spatial scales. This paper presents part of an ongoing research effort to develop a new, comprehensive decision support tool for watershed-scale BMP design. The current model is designed to identify detention pond sizes that best achieve target peak flow reduction criteria. It is developed by coupling the U.S. Department of Agriculture's (USDA) Soil and Water Assessment Tool (SWAT) and a genetic algorithm. The model is applied to Silver Creek watershed, a subbasin of the larger Lower Kaskaskia watershed in Illinois. The results show that detention ponds can be designed at a holistic, watershed scale to more effectively achieve peak flow reduction goals. Future work will focus on expansion of the model, which will also be disseminated through outreach workshops in portions of Illinois and surrounding states.

Strategic management of agricultural watersheds is essential to achieve increased production of ecosystem services (e.g., reduction of non-point source pollutants, flood peak reduction, expansion of wildlife habitat and biodiversity) and agricultural commodities. This paper presents a multi-objective optimal control model (OCM) for watershed-scale management of ecosystem services through coupling a semi-distributed hydrologic model, SWAT with a multi-objective optimization algorithm, NSGA-II. The computational model is designed to identify land uses and management practices that could result in improved production of ecosystem services and maximized net gross margin. The ecosystem service objectives considered in this study are the reduction of flood peaks and non-point source pollutants (NPS) including sediment, nitrogen and phosphorus yields whereas the economic objective is maximization of net gross margin. Based on the close relationship between these ecosystem service objectives, a hydrologic and water quality index (HWI) is introduced to indicate the level of ecosystem service generation. The HWI helps reduce the dimensionality of the overall optimization problem. Application of the OCM to the Big Creek watershed in southern Illinois indicates that the model is effective in identifying optimal tradeoffs between these conflicting objectives, i.e., improving the generation of ecosystem services and maximizing agricultural production. Thus, the OCM can be used as a decision support tool for cost-effective management of watersheds, enabling stakeholders and policy makers in identifying a suitable set of land use and management practices at a watershed scale.

Control of sewer overflows, the leading cause of water pollution in the nation's water bodies, is vital to reducing risks to public health and protecting the environment. The most common solutions for mitigating sewer overflows include adding storage volume, increasing conduit capacity, expanding pumping capacity, and implementation of real time operational controls to more effectively utilize existing system storage. Obviously, comprehensive modeling and analysis of these sewer systems becomes necessary for developing sound cost-effective and reliable solutions for enhancing system integrity and performance to convey sewer flows without causing overflows. However, identification of the optimal remedial solution that effectively circumvents overflow problems with the least expenditure is a daunting task. The current practice involves a tedious trial-and-error evaluation procedure that seldom leads to the most effective or most economical solutions. Another emerging design approach utilizes single objective optimization that identifies the solution that best satisfies a predefined criterion. The performance criterion used with single objective optimization subjectively lumps the economics objective with metrics that measure effectiveness of the remedial solution from the perspective of avoiding overflows (e.g., minimizing the number of flooding events or reducing the flooding volume). Consequently, the design solution identified using single objective optimization depends on the weights subjectively placed on the two incommensurable and conflicting objectives, and may not represent the global optimal solution. A preferable approach is to seek tradeoff solutions commonly referred to as non-dominated solutions or Pareto-optimal solutions. The methodology proposed here links an extended version of the EPA SWMM 5 model, a comprehensive drainage network simulator, with NSGA-II, an evolutionary multiobjective optimization method with a proven history of identifying Pareto-optimal solutions for a wide range of engineering problems. The method should prove useful to any wastewater utility attempting to improve system integrity, reliability and performance and optimize its capital improvement program.

Available water resources are often not sufficient or too polluted to satisfy the needs of all water users. Therefore conflict over water, as a result of limitations on quantity and quality of water is a major challenge in water allocation. In this study, a methodology for river water quality management considering in water user/ stakeholders preferences satisfaction is presented. The dissatisfactions of each water user and stakeholders are the difference between the allocated water quality and quantity and the users' demand as well as water quality requirement of each user. The objective function of the optimization model is to minimize user dissatisfaction due to quality and quantity of allocated water to each sector and quality and quantity of wastewater and return flows discharged by each user to the river. To evaluate the spatial and temporal variation of the concentration of the water quality indicators in the system, a water quality simulation model is linked to a GA-based optimization model. The model is applied to the Karkheh river system in southwest of Iran. The results in forms of reliability, resiliency and vulnerability of the system are determined which show the significant value of the proposed methodology in river water quality management with conflicting objectives.

In the core of an integrated watershed model is the coupling among surface water and subsurface water flows. Mathematical, there are two approaches of surface/subsurface coupling based on the physical nature of the interface: continuous or discontinuous assumption. Physically, only the continuous case exists in nature. However, when a far less permeable layer exists at the interface, the layer may be removed for computational efficiency. Under such circumstances, the discontinuous simplification may be justified. Numerically, there are three strategies of coupling between surface water and groundwater water: time-lagged, iterative, and simultaneous solutions. Current literature is dominated by the discontinuity assumption with the simultaneous solution strategy. Since modelers often resort to the simplest, fastest schemes in practical applications, it is desirable to quantify potential errors and the performance specific to each coupling scheme. This paper evaluates these coupling schemes in watershed modeling with WASH123D. Numerical experiments are used to compare the performance of each coupling approach and strategy for different types of surface water and groundwater interactions. These experiments are done in terms of errors in state variables (e.g., water depth and pressure head) and fluxes (e.g. infiltration/seepage rate). It is found that different coupling approaches and strategies are justifiable for only the specific flow problem of physical setting of interfaces and the specific scale of time and space. Therefore, for practicality and for accurate and efficient simulations, a watershed simulator should include various options of mathematical approaches and numerical strategies. However, the time-lagged strategy should be avoided since it generally produces too much error in solutions in fluxes, thus causing problem of mass conservation across the interface.

The Picayune Strand Restoration Project, a component of the Comprehensive Everglades Restoration Plan (CERP), aims to restore the hydrology of approximately 95 square miles of drained wetland areas in Southwest Florida. The restoration of the Picayune Strand is important because of its location and connectivity to critical preserved areas that serve as wildlife habitat and also the headwaters of the Ten Thousand Islands estuary. The excessive drainage of this area have had several detrimental ecological and hydrologic impacts such as: reduction of groundwater levels, increased freshwater loads to critical estuaries, increase of invasive exotic vegetation and upland species, increased fire frequency, and loss of wildlife habitat connectivity. To evaluate a proposed restoration plan previously developed, two integrated surface water and groundwater models were developed for the area. Two models were developed using MIKE SHE/MIKE 11 in order to simulate different hydrologic aspects of the proposed restoration plan. The previous paper discussed the Phase I HDT model that was developed to simulate the response of the surface water system to short-term high-intensity events. This paper focuses on the Phase II model that was developed to simulate surface water and groundwater responses under a variety of hydrologic conditions. The Phase II model was developed from the Project Implementation Report model (PIR) and was updated to include newly acquired topographic and aquifer data, a more detailed representation of the channel system, and refined structure data. Although the model was based on previous calibrated models the Phase II model calibration process was extensive as a result of significant differences between datasets used in the PIR and Phase II model. The Phase II model was calibrated to dry, wet, and average conditions and does a good job of simulating surface water stage and water table aquifer water levels. Simulated groundwater levels in the lower Tamiami and Sandstone aquifers are adequate but model performance is poorer in these aquifers because of the Limitations of the available groundwater pumpage data. Because the proposed restoration plan will primarily impact the surface water system and the water table aquifer the Phase II model calibration is sufficient to evaluate the long-term benefits of the proposed restoration project.

Research has pointed out that subsurface contributions may play an important role in predicting surface runoff and water depth during a rainfall event. A fully implicit coupled surface-subsurface flow model designed for hydrologic evaluation in wetlands and other fields is presented in this paper. In the model, the modified horizontal two-dimensional diffusion wave equation governing surface flow is solved with three-dimensional variably saturated subsurface flow equation in a coupled way. The coupled system of equations governing surface and subsurface flows is discretized using the finite volume method in space and the implicit backward scheme in time. The modified Picard procedure is used to linearize the surface and subsurface flow equations. The discretized algebraic equation system is solved using Stone's Strongly Implicit Procedure. The established model is used to simulate the storm event in the Deephollow Lake watershed, which is located within the Yazoo River Basin, North Mississippi. The lake is in the center of an agricultural watershed and surrounded by approximately 232 acres of cotton and soybean fields and wooded area. The numerical solution shows that the developed integrated surface-subsurface flow model is able to predict the hydrological response in surface and subsurface domains due to rainfall.

In this study, saltwater intrusion in coastal aquifers and prevention techniques were investigated using a new computer model, the Sea Water Intrusion (SWI) package (Bakker and Schaars, 2005), which simulates three-dimensional regional seawater intrusion in coastal multi-aquifer systems. Prevention methods consisting of injection wells, extraction wells, a combination of injection and extraction wells, and a subsurface barrier were evaluated as means of controlling saltwater intrusion by using SWI to simulate groundwater flow in an idealized rectangular coastal aquifer with a pumping well. For the first case, a line of injection wells was located along the column between the sea and the pumping well. For the second case, a line of extraction wells pumping saltwater was located between the sea and the pumping well. The third case consisted of a line of injection wells and a line of extraction wells. In order to represent the subsurface barrier, the hydraulic conductivity along a column towards the sea was reduced. The results obtained were compared to each other, and the subsurface barrier technique was determined to give the best result, i.e., it resulted in the least amount of upconing beneath the pumped well.

Since 1980, several numerical models of groundwater flow and salinity transport have been developed for Hawaii basal aquifers. At this time, however, they are too complicated as viable management tools because adequate calibration and verification of these models require extensive field data which are not currently available. In our study, a simple robust analytical model called RAM2 was developed by taking Hawaii basal aquifers as a completely stirred tank reactor. RAM2 consists of (a) a flow submodel and (b) a salt transport submodel which simulates the evolution of the transition zone in a basal freshwater lens. The mathematical structure of RAM2 is simple, such that it can be solved analytically and can be readily calibrated using available field data. Its usefulness as a management tool was demonstrated by applying it in an evaluation of the sustainable yield of the Iao aquifer on Maui, Hawaii.

Lockport Prairie Nature Preserve (LPNP) is located adjacent to the Des Plaines River in Will County, Illinois. LPNP provides habitat for several threatened and endangered species including the Federally-endangered Leafy Prairie Clover and Hine's Emerald Dragonfly. Dolomite prairie is one of the rarest community types in Illinois. LPNP currently contains the highest concentration of high quality dolomite prairie in Illinois. The ecosystem is supplied by ground water by a dolomite aquifer known as the Niagara Dolomite, which crops out along a 40-foot high bluff. Ground water enters LPNP through seeps along the bluff and through diffuse discharge. A limited offsite watershed immediately to the west adds surface water. In order to understand the ground water and surface water dynamics, ongoing investigations were initiated in 2001. It was considered essential to understand the ground water and surface water mechanisms before restoration plans could be evaluated.

This study develops a saltwater intrusion simulation model using a lattice Boltzmann method (LBM) in a two-dimensional coastal confined aquifer. The saltwater intrusion phenomenon is described by density-varied groundwater flow and mass transport equations, where a freshwater-saltwater mixing zone is considered. Although primarily developed using the mesoscopic approach to solve macroscopic fluid dynamic problems, e.g., Navier-Stoke equation, LBM is able to be adopted to solve physical-based diffusion-type governing equations as for the groundwater flow and mass transport equations. In this study, the density-varied groundwater flow equation and the advection-dispersion equation (ADE) are modeled by the lattice Boltzmann method. Under the consideration on the steady-state groundwater flow due to low storativity, in each time step the flow problem is modified to be a Poisson equation and solved by LBM. Nevertheless, the groundwater flow is still a time-marching problem with spatial-temporal variation in salinity concentration as well as density. The Henry problem is used to compare the LBM results against the Henry solution.

This paper presents the development and application of a multi-objective geostatistical sensitivity approach to identify gaps and redundancy in a surficial aquifer's monitoring-well network. The key to this approach is the identification of areas where high surficial aquifer system (SAS) water level uncertainty coincide with high SAS water-level sensitivity to pumping in the underlying Upper Floridan Aquifer. The methodology identifies monitoring gaps and redundancies using a multi-objective approach in which an importance score of gaps is calculated. Modifications to the network are guided by geostatistics with the goal of minimizing the gap score. The development and subsequent application of the methodology to a monitoring network currently in use by a major Florida water supplier is described.

This study presents a framework for Visually Interactive Decision-making and Design using Evolutionary Multiobjective Optimization (VIDEO). The VIDEO framework allows users to visually navigate large multiobjective solution sets while aiding decision makers in identifying one or more optimal designs. Specifically, the interactive visualization framework is intended to provide an innovative exploration tool for high-order Pareto-optimal solution sets (i.e., solution sets for three or more objectives). The framework is demonstrated for a long-term groundwater monitoring (LTM) application in which users can explore and visualize tradeoffs for up to four design objectives, simultaneously. Interactive functionality within the framework allows the user to select solutions within the objective space and visualize the corresponding monitoring plan's performance in the design space. This functionality provides the user with a holistic picture of the information provided by a particular solution, ultimately allowing them to make a more informed decision. In addition, the ease with which the framework allows users to navigate and compare solutions as well as design tradeoffs leads to a time efficient analysis, even when there are thousands of potential solutions.

Subsurface contamination problems of metals and radionuclides are ubiquitous. Metals and radionuclides may exist in the solute phase or bound to soil particles and interstitial portions of the geologic matrix. Accurate tools to reliably predict the migration and transformation of these metals and radionuclides in the subsurface environment enhance the ability of environmental scientists, engineers and decision makers to analyze their impact and to evaluate the efficacy of alternative remediation techniques prior to incurring expense in the field. A mechanistic-based numerical model could provide such a tool. This paper communicates the development and verification of a mechanistically coupled fluid flow and reactive chemical transport under both fast and slow reactions in variably saturated porous and fractured media. Theoretical bases, numerical implementations, and modeling experiments of the model will be described. Two example problems will be presented. The first one will be a reactive transport problem to elucidate the non-isothermal effects on heterogeneous reactions. The second problem involves coupled fluid flow and reactive transport in fractured media. It purposes are to examine the effects of precipitation and dissolution on fluid flow and matrix diffusion. It would help shade some lights on the retardation ability of grain matrices on the migration of metals and radionuclides.

Following release of pesticides into the environment, they undergo a series of physical and (bio)chemical processes. Leaching in the vadose zone and further down to an underlying aquifer is one of the primary pathways of pesticides, which induces contamination of the subsurface environment. A variety of mathematical models have been developed for simulating pesticide fate and transport in the vadose zone. They have various limitations and thus they are suitable for specific conditions and research purposes. Their performance can be evaluated theoretically by analyzing the errors introduced from modeling assumptions and/or numerical approximations. In addition, they can be evaluated by comparing their simulations against the observed data. A critical issue is how to compare them. Field samples are often space and time specific. In other words, a "grab" sample in the field represents the pesticide level at a specific space/time point. A model, however, often provides an averaged level over a space volume during an interval of time. Sometimes, the representative volume can be too large to capture the real spatial variability in pesticide exposure levels. Worse of all, a model may average over a much larger space domain far beyond the range pesticides can reach. In such a case, the model actually "speeds up" the transport of pesticides. Thus, an improper selection of the spatial and temporal scales may lead to incorrect environmental assessment conclusions. In this study, a Windows-based, integrated pesticide transport model (IPTM-CS) is used for simulating three-phase pesticide fate and transport in the vadose zone. Various spatial discretization schemes are examined and the corresponding simulations are compared. Particularly, effects of the spatial and temporal modeling scales on the model performance are discussed. It is concluded that special caution should be taken in comparison and calibration of pesticide transport models and different evaluation criteria should be used, depending on their time and space scales.

Wavelet analysis involves an integral transform of, for example, a permeability data set, using 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. Using wavelet analysis, dominant scales of permeability can be identified in a statistically heterogeneous porous medium. We generate sets of random permeability fields with different spatial correlation lengths, and we run numerical flow and solute transport simulations using these random fields. We show preliminary results of using wavelet analysis to analyze the dominant scales in the random permeability fields. The results of wavelet analysis will be used to identify relationships between dominant scales of heterogeneity and scales controlling the transport of contaminants.

A solution in which drawdowns are calculated in a one-dimensional leaky aquifer subject to a specified discharge pumped from a canal was used to determine properties for the Biscayne Aquifer adjacent to the Everglades National Park in southeastern Florida, U.S.A. This solution, in which a Laplace-space solution for drawdowns is inverted numerically to the time domain, considers the effects of the discharge being partly derived from storage in a finite-width canal and the additional resistance due to canal sediments expressed as a skin effect. In this application, the discharge from a length of the L-31N canal was maintained at a nearly constant rate during a canal pumping test, and groundwater levels were measured in monitoring wells adjacent to L-31N. A match-point procedure was used to calculate values for aquifer and canal parameters using drawdown data from the monitoring wells. At well MW-2, which is located 640.1 m west of L-31N, values for transmissivity and storativity were determined to be T = 2.31 x 10⁵ m²d^–1 and S = 0.20. During the test, the Biscayne Aquifer in the vicinity of L31-N and well MW-2 was unconfined, and there was no vertical leakage from overlying ponded areas into the aquifer. Thus, leakance K'/b' = 0. The coefficient for skin friction, which is the ratio of the hydraulic conductivity of the Biscayne Aquifer in the vicinity of L-31N divided by the leakage coefficient for sediment deposits in L-31N, was S_k = 156.8 m. For this analysis at well MW-2, the effects that pumping from storage in the canal and the skin effect due to canal sediments had on aquifer drawdowns were small, but significant. For wells closer to L-31N, the effects of pumping from storage in the finite-width canal and the skin effect were greater.

In 2006, Congress directed the U.S. Department of Energy (DOE) to undertake a study of the potential purchase of property or options to purchase property located above the plumes of contaminated groundwater (Trichloroethene and Technitium 99) near the Paducah Gaseous Diffusion Plant (PGDP) in Paducah, Kentucky. The objective of the study was to evaluate adequate protection of human health and environment from exposure to contaminated groundwater and consider whether such purchase, when taking into account the cost of remediation, long-term surveillance, and maintenance, is in the best interest of taxpayers. In response to this directive, the Kentucky Water Resource Research Institute was contracted to perform a study and develop a report for subsequent submission to Congress. The subsequent study involved the application of MODFLOWT and ArcGIS as well as an economic analysis to determine the potential economic benefit of different institutional controls and associated remediation actions. This paper will summarize the associated modeling of that study.

Improved understanding of bacterial behavior in watersheds is necessary in order to develop management strategies for mitigation of pathogen-impaired water quality. Bacterial occurrence and persistence in streams have been demonstrated to be linked to certain hydrologic processes. The hydrologic processes may involve interactions or storage in surface or sub-surface reservoirs. Spectral analyses may provide some insights into the behavior of bacterial loading and interface with certain hydrologic reservoirs. Spectral analysis of daily total coliform data for the Little River, in East Tennessee from October 1, 2000 to December 31, 2005 was used in this case study to elucidate behavior characteristics. The objective of the study was to analyze the total coliform concentration data to determine whether this indicator demonstrates any long-term or short-term persistence and temporal scaling using spectral analysis. The pathogen indicator concentration showed short-term as well as long-term persistence ranging from about 14 weeks to approximately one year. It is speculated that hydrologic influences (surface and subsurface flow) are responsible for short-term and long-term persistence.

Regulatory, political and economic constraints have shaped wastewater management strategies in Southeast Florida. Three options are currently available: Class I injection wells, ocean outfalls and reclaimed water. Class I injection wells have been used extensively for the disposal of secondary treated wastewater and concentrate in southeast Florida. Injection wells have been found to be the option with the lowest relative risk of impact to water consumers in the southeast coast. A prior study by the authors found that all the injection wells were over 2,400 feet deep, and typically over 3000 feet deep. Only two sets of wells indicated any migration in the lower monitoring zone, and in both cases there were injection well construction issues that have long-standing relevance to the findings. None of the upper monitor wells showed migration. Water quality was stable in most of the wells with periodic fluctuations that have no apparent relationship to injection rates or well use. The data gathered for this project was used to valuate modeling of individual wells. The intent was to determine the real likelihood of there being migration, and what might stop that migration. Density differential and diffusion were likely causes. The modeling is intended to initiate modeling discussions — that more calibration and comparisons are required.

This paper uses DRASTIC Model to evaluate vulnerability impact on aquifers from nitrate contamination. The contamination occurs due to fertilizer application in agricultural areas in central States of United States. This nonpoint source pollution problem can be effectively analyzed using the DRASTIC Model integrated on an ArcGIS platform. This research presents an example of analysis in Enid region in Oklahoma for nitrate contamination. The results are validated with observed data of high nitrates in Enid area for 2004–05. The methodology is versatile and can be applied to aquifers anywhere in the US or around the world.

One-dimensional unsteady flow in a finite confined fractured aquifer resulting from a constant discharge, pumped from a stream, is considered. The stream is assumed to penetrate the full thickness of the aquifer. The governing differential equations are based on the double porosity conceptual model with the assumption of pseudo-steady state fracture-to-block flow. A new transient solution is developed by solving the governing differential equations analytically in Laplace domain and then inverting Laplace space solution to real physical domain by using the Stehfest numerical algorithm. The resulting solutions relate the drawdowns in the aquifer to aquifer parameters and the discharge out of the stream. The validity of the proposed method is checked by comparing the results with the available exact analytical solutions for the case of homogeneous aquifers. A non-dimensional drain function D (u,η,δ) is defined based on the solution. Selected type curves for the drain function are plotted. These proposed solutions may be used to predict the drawdowns in the aquifer in the prediction problems. They may also be useful for the validation of numerical models. It is also stated that, based on these solution, techniques may be developed for the determination of the aquifer properties in the identification problems.

Water agencies across the U.S. face a formidable challenge to address high levels of arsenic encountered in existing groundwater production wells. With recent implementation of the U.S. Environmental Protection Agency's new maximum contaminant level of 10 parts per billion for arsenic in drinking water, water agencies have struggled to identify and implement cost-effective mitigation methods to address arsenic. This paper describes a cost-effective, non-treatment method to mitigate for arsenic by partially abandoning existing groundwater wells.

This study utilizes GWM to optimize water withdrawals in a transient regional model that is represented by MODFLOW. The study focuses on the behavior of a linear programming solution algorithm when the aquifer is represented as confined and unconfined and the behavior of a sequential linear programming algorithm for the unconfined case. The study utilizes a model for the Antelope Valley in California which has experienced extensive water table declines and land subsidence in recent decades. While the results are not intended for practical application to Antelope Valley, they do show consistency between the algorithms used and indicate that GWM can function effectively on a large-scale transient problem.

This work combines the Genetic Algorithm (GA) and Constrained Differential Dynamic Programming (CDDP) to solve the optimal pumping schedule and decreasing the environmental impact. The main structure of the hybrid algorithm is GA, in which each chromosome represents a possible network design and pumping wells expansion schedule. The fixed cost of each chromosome is computed easily by the GA. The CDDP then solves the optimal pumping scheme and, finally, evaluates the optimal operating costs associated with each chromosome. Simulation results indicate that under the same demand and annul interest rate, the capacity-expansion model has a lower total cost than the conventional design, which determines the system capacity initially. Furthermore, the land subsidence increases as total demand increases. The results further demonstrate that the proposed model is highly promising for use in facilitating a cost-efficiency design of well systems for regional groundwater supply and environmental preservation.

One-fourth of the water consumed in the United States today is groundwater—including about one-third of the water used in the western states. Half of the people in the United States drink groundwater. Groundwater down to a depth of one-half mile is six times as much as the available surface water in the United States. Yet ground-water is not an inexhaustible resource: Current usage depends on withdrawals substantially in excess of natural recharge of the groundwater. Changes in technology and changes in demand have given the controlling law a dynamic character. The traditional legal neglect of groundwater has given way to statutory and regulatory intervention by the state and federal governments and to frequent litigation between private parties over the right to use groundwater and the responsibility to protect it. This paper summarizes the law presently applicable to groundwater in the United States.

The publicly available analytical contaminant transport analysis system (ACTS) was used to examine the fate and transport of organochlorine pesticides in shallow groundwater at the Oatland Island Education Center, Oatland Island, Georgia. Specific objectives of the analysis included: (1) estimating the probability of impacting coastal wetlands located 800 feet (244 meters) downgradient of the pesticide source area, and (2) developing reference tools (probability curves) for evaluating future groundwater monitoring results at key site monitoring wells. The groundwater contaminant plume consists of four different isomers of benzene hexachloride (BHC). Total BHC was selected as the reference contaminant for the contaminant, fate and transport model simulations. Probabilistic model results for each specific site location and time period were generated by conducting two-stage Monte Carlo simulations for eight model parameters using 10,000 realizations for each probability distribution. Model results are considered representative of all four BHC isomers detected at the site. According to simulation results at the wetlands boundary, the probability of total BHC concentration in groundwater exceeding the analytical detection limit of 0.04 micrograms per liter (μg/L) is less than 2%. The detection limit of 0.04 μg/L is a default compliance standard for BHCs in groundwater, in accordance with applicable Georgia Environmental Protection Division rules. Model simulation results were used to develop a series of probability curves for four different site locations — three downgradient monitoring wells and the downgradient wetlands boundary — along the centerline of the contaminant plume. These probability curves are useful in evaluating future groundwater monitoring results and guiding environmental and regulatory decision-making for the site.

Lockport Prairie Nature Preserve (LPNP) is located adjacent to the Des Plaines River in Will County, Illinois. LPNP large expanses of Dolomite Prairie, Sedge Meadow, and Marsh plant communities. These communities provide habitat for several threatened and endangered species including the Federally-endangered Leafy Prairie Clover and Hine's emerald dragonfly. There have been two distinct phases of ground-water modeling for LPNP. The first phase was an interpretive quasi-stochastic modeling effort. The current phase is a calibrated aquifer model based on the results of the first phase. The size and location of the LPNP recharge area was sensitive to ground water withdrawal. As additional withdrawals were added, the model recharge area was reduced in western extent. The size and location of the LPNP recharge area was also sensitive to the material properties of the upper bedrock units.

Uncertainties in input parameters, such as hydraulic conductivities, may result in inconsistencies between simulated and observed groundwater flows and contaminant plumes. If a groundwater management model for aquifer remediation design is based upon incorrect input, non-optimal remediation policies may result. Typically, aquifer uncertainties have been simulated by generating multiple realizations of unconditional hydraulic conductivity fields. To reflect a truer picture of the actual hydraulic conductivity field, thereby improve on the performance of the optimal remediation design, random conductivity fields have been conditioned to honor the values of the field measurement. However, the potential benefits of conditioning the random conductivity fields within a robust groundwater remediation optimizer have never been systematically demonstrated. Furthermore, the additional measurements of conductivity needed for conditioning come at a financial cost. This study expands upon previous robust optimal design studies through incorporation of random fields conditioned on localized field observations. In the study, the impacts of conditioning on both the costs and the reliability of the optimal remediation designs are explored by comparison to robust optimization using unconditional random fields and by varying the number of data points utilized for conditioning. An example cost-benefit analysis of the value of additional samples for conditioning will be presented.

This paper presents a reliability-based water resources management framework that utilizes stochastic optimization techniques to account for uncertainties associated with of prediction of climatic condition, water demand, surface water availability, baseline groundwater levels, non-anthropogenic reservoir water budget, and hydrologic/hydrogeologic properties. The framework was developed to manage water resources from over 180 groundwater production wells, stream flow withdrawal, regional reservoir, and desalination plant in the Tampa Bay region in Florida, USA. The developed method maximizes the reliability of achieving the goals that all protected wetlands in the area are healthy and sea water intrusion is prevented. The framework involves (1) a system simulation model to represent the water resources routing under the OROP and (2) a Monte Carlo simulation model to generate realizations of climatic events, water demand, available surface water quantity, and (3) a unit response matrix (URM) that relates groundwater level response to groundwater extraction. A simulator response model simulates how water supply operators adjust the optimized rates of groundwater extraction, surface water withdrawal, and reservoir inflow/outflow according to meeting the water demand in all circumstances. The reliability optimization problem is solved using a differential evolutionary algorithm.

Management of contaminated groundwater resources has been a challenge due to limited resources committed to monitor and remediate a large number of contaminated sites. Therefore, there is an important question on the optimal allocation of resources for additional data collection and remedial measures. In this work, we extended the risk assessment methodology under subsurface heterogeneity and population variability proposed by others to estimate individuals' willingness-to-pay (WTP) for a proposed risk reduction by adding socio-economic measures. We introduced one of the early applications of welfare measures namely, health state, utility, and WTP concepts to study the benefits and costs of collecting additional data to reduce uncertainty for groundwater remediation. The proposed framework considered uncertainty due to subsurface heterogeneity and public health risk through a utility theory based approach that can be used in decision-making. Our framework replaced costly contingent valuation approaches and used a meta analysis which considered a theoretical structure on population age, income, and health state, and used empirical estimates from previous contingent valuation methods. We also performed sensitivity analysis on important variables such as WTP and utility levels. Our findings showed that health state and age have vital impacts on WTP. The predictions of WTP trends are consistent with patterns expected in economic theory. We illustrated the proposed framework by evaluating two scenarios of gathering additional information to better describe subsurface heterogeneity. In this example we considered a small addition of data at a correlation scale of 112 m versus a large addition of data at a correlation scale of 22 m. The results showed the two scenarios have annual individuals' WTP of $258 and $330, respectively indicating a 28% increase in individuals' WTP for additional information.

Optimization modeling has been shown to be an important tool for cost-effective groundwater remediation. Currently most optimal remediation design tools are deterministic, assuming full knowledge of all inputs. Those that include uncertainty, typically utilize a random sampling of possible conductivity fields as input, with each realization presumed equally likely. This study develops and evaluates a scaled likelihood (ScL) approach to robust remediation design. An existing robust optimizer that links a three-dimensional numerical flow and transport simulator to a genetic algorithm (GA) is modified to the ScL approach. The robust optimizer considers different possible conductivity fields in each generation of the GA search and searches for a robust design that performs well across multiple feasible realizations. In the ScL approach, multiple conductivity realizations are still utilized, but greater weight is placed on the conductivity realizations that result in more accurate representations of the initial plume concentration measurements. The ScL approach impacts the estimated initial plume concentrations, the measure of fitness across realizations, and the estimated reliability of a remediation policy. The remediation costs and reliability of the ScL-based solutions will be compared to those found using the existing optimizer. Furthermore, computational effort of the two approaches will be compared.

An investigation regarding the feasibility of using a wind turbine to power a groundwater circulation well (GCW) at the former Nebraska Ordnance Plant Superfund site focused on the economic and environmental benefits associated with the renewable energy application. The first phase of the project consisted on the installation of a grid inter-tie wind turbine, and the second phase involved the conversion of the system to off-grid operation. An analysis was performed to characterize the likelihood that the wind turbine systems reduced the quantity of electricity purchased from the utility company. The environmental benefits of the wind turbine/GCW system include the removal of contaminant mass without loss of groundwater to the aquifer and the potential reduction in carbon dioxide released to the atmosphere. The wind turbine manufacturer's performance prediction model was evaluated for reliability given the investigation results.

A soil and groundwater remediation system was designed and installed at the 60 Minute Cleaners in Ft. Myers Florida under the State of Florida Drycleaning Solvent Cleanup Program (DSCP) in March 2003. A contamination assessment was completed at the facility which showed chlorinated solvents concentrations, associated with drycleaning operations, exceeding soil and groundwater cleanup target levels beneath the facility with a groundwater plume migrating approximately 200 feet downgradient of the facility. A remedial system was designed and implemented which included a soil vapor extraction (SVE) system to address affected soil. To address affected groundwater, nested groundwater extraction wells were installed downgradient of the drycleaning facility and multiple injection wells installed upgradient of the facility. The primary objectives for installation and operation of the remediation system were: 1) Enhance the rate of dechlorination of dissolved chlorinated ethenes with indigenous microorganisms in the presumed source area (beneath the former drycleaning facility) by injecting ethyl lactate into the surficial aquifer. A groundwater-extraction system, with recovery wells downgradient of the source area and re-injection wells upgradient of the source area, provides accelerated movement of the ethyl lactate through the aquifer in the source area. It is expected that intrinsic natural-attenuation processes will be adequate for remediation of dissolved-phase chlorinated ethenes outside of the source area. Dissolved chlorinated ethenes in the remediation-system influent water stream are removed by carbon adsorption with two 2,000-pound granular activated carbon (GAC) vessels, and 2) Decrease the concentrations of chlorinated ethenes in the presumed source-area vadose-zone soil with an SVE remediation system. Chlorinated ethenes within the soil-vapor stream were initially removed prior to atmospheric discharge by two 170-pound GAC vessels. The SVE remediation system was turned off on September 6, 2005, and the groundwater-remediation system was turned off on October 14, 2005, to allow the Site to be monitored for natural-attenuation processes. Chlorinated-VOC concentrations have significantly decreased on both a mass and molar basis since startup. A significant decrease in dissolved tetrachloroethene (PCE) concentrations in monitoring wells was observed in the source area, while an increase in dissolved-PCE breakdown products was observed throughout the Site in monitoring wells outside of the source area, especially VC concentrations. Based on recent data, the VC concentrations have shown a decreasing trend in the monitoring wells during the third year of remediation-system operation. During the March 2006 sampling event, there was a continued decrease in the concentration of dissolved chlorinated-ethenes in groundwater. Chlorinated-ethene concentrations remained below the Florida Department of Environmental Protection's (FDEP) natural attenuation default concentrations (NADCs) in the monitoring and recovery wells sampled during March 2006 sampling events.

Monitored natural attenuation (MNA) was selected ten years ago by previous operators of a Superfund site in Florida as a remedy for metals-affected groundwater impacted from the historical operation of wastewater evaporation ponds at a metal galvanizing plant. The Record of Decision (ROD) stipulated that MNA should result in a decrease of dissolved zinc and nickel concentrations in a shallow sandy aquifer to the Performance Standards within 7.6 years of pond closures, or else the implementation of a groundwater-recovery-and-treatment contingency remedy would be required. The groundwater model, used by others to estimate the time to achieve the Performance Standards via natural attenuation, assumed no contaminant retardation, and no other potential sources, including releases from the current operator. This model predicted that zinc concentrations would be reduced from a range of 140,000 to 190,000 μg/L, to 10,000 μg/l by natural groundwater dilution or flushing. Historical results indicated substantial decreases of zinc and nickel concentrations, but not to levels below Performance Standards. Therefore, the U.S. EPA concluded that MNA was not a viable remedy and would not result in cleanup within a reasonable time frame. Before moving forward with the contingency remedy, LFR recommended a re-evaluation of the conceptual site model (CSM) to better understand site hydrogeology and to optimize full-scale remediation. It was suspected that the same conditions that limited the effectiveness of MNA would also limit the effectiveness of the groundwater-recovery-and-treatment contingency. Therefore, additional characterization data were collected to develop an appropriate CSM for the Site that would assist in determining the appropriate remedial approach and also shed light on why MNA was not effective. Additional characterization included horizontal and vertical groundwater data collection using direct push technology and nested wells; detailed geochemical analysis; and 3-dimensional imaging of hydrostratigraphic units. The new data helped determine the distribution of a clayey-sand transition zone between the high-conductivity shallow sand aquifer and the underlying low-conductivity clay formation. The 3-D imaging showed the presence of paleostratigraphic depressions in the underlying clay formation, probably a result of karst-related sinkholes in the deeper limestone. Geochemical data indicated the presence of higher concentrations of metals and total dissolved solids in the clayey-sand transition zone relative to the overlying sand aquifer. Based on the revised CSM, it appears that high-density wastewater from the former ponds moved both vertically and horizontally into the surficial aquifer, and penetrated down to the clayey-sand transition zone. Although MNA appears to have progressed as modeled in the sandy surficial aquifer, higher concentrations of metals were retained in the clayey-sand transition zone due to the higher sorption capacity of this unit. Furthermore, the paleostratigraphic depressions in the clayey sediments further slowed down the horizontal movement of metals in the lower part of the aquifer. Based on the additional characterization data and the revised CSM, groundwater-recovery-and-treatment was no longer considered viable due to the majority of the metal mass residing in low-conductivity soils. The U.S. EPA concurred with this conclusion. LFR has proposed an in situ treatment remedy, which is currently being bench- and pilot-tested.

Working for a multinational manufacturing company, URS completed the implementation of groundwater remedial measures at a Superfund landfill in Vermont. URS demonstrated that a revision of the ROD remedy from pump and treatment to a combination of passive and semi-active treatment controls would effectively treat groundwater and reduce clean-up costs by $20 million. URS evaluated alternative technologies and to demonstrate corresponding performance effects. The evaluation successfully resulted in EPA's issuance of an Explanation of Significant Differences changed to the ROD. The selected remedy included construction of a source-area permeable reactive barrier (PRB) coupled with a bio-enhanced attenuation system to treating downgradient groundwater. The 235-foot-long, 62-foot-deep PRB was installed by slurry wall construction methods and employed variable iron content media placed in sections of the wall to reduce the quantity of reactive media required. The bio-enhanced attenuation system enhanced in-situ microbial degradation treats groundwater depths of between 120 and 160 feet by injecting a solution containing sodium lactate and nutrients. Monitoring of the two treatment systems indicates that significant destruction of contaminant mass is occurring.

Three different bi-directional autonomous groundwater/surface water seepage meter prototypes were designed and developed from 2003 to 2006 under the collaboration of FDEP, FSU and SDI Environmental Services, Inc. All three seepage meters are self-contained automated systems including seepage collector, flow rate sensor, on-board controller, data logger, battery pack, and deployment/retrieval accessories. The first seepage meter design uses a Doppler flow rate sensor mounted on top of the seepage collector. The second seepage meter design uses a thermal flow rate sensor with detached seepage collectors. The latter design allows the use of multiple collectors to increase/decrease the measurement range of the meter. The three different meter sensors and collector combinations allow the measurement of seepage rates over a relatively wide range, with some overlap. The Doppler seepage meter has the highest measurement rate which is suitable for seashore and high seepage rate locations deployment. The two thermal seepage meters have low measurement rates which are suitable for lakes, rivers, and low seepage rate locations deployment. All three seepage meters were tested in the lab and field and proved to be easy to deploy and retrieve, and were dependable for long-term operation and monitoring of groundwater/surface water interactions.

Significant advances in research can be achieved most often by applying a new tool to an old problem, an old tool to a new problem or a new tool to a new problem. In subsurface hydrology the new practical, or engineering related problems appearing in the last three decades have been associated primarily with groundwater contamination by anthropogenic compounds. From a more scientific perspective, coupled systems, such as groundwater-surface water interaction can be considered new problems because they were intractable prior to the advent of new computational tools. The new computational tools are, generally speaking, extensions or modifications of existing tools that have been adapted to exploit the growth in computer power over this period. Such tools are, for example, numerical analysis, geostatistics, multiphase flow and transport theory, operations research, and some relatively unknown methods such as Kalman filtering. In this presentation advances attributable to research conducted by the author that were realized through the utilization of new tools to solve both new and existing problems is reviewed.

The KSTAT Standard Committee of the Environmental Water Resources Institute (EWRI) and the American Society of Civil Engineers (ASCE) initiated activities in year 2005. Over the last two years, the KSTAT Committee has produced two preliminary standard-guidance documents expected to be published by ASCE following public review. This paper summarizes the key methods presented in the two standard-guidance documents, highlighting the potential areas of application in groundwater hydrology and geotechnical engineering.

Sanitary engineering education in Texas began in 1894. The catalog of the Department of Engineering at The University of Texas at Austin (UT) in that year listed a four-year curriculum in sanitary engineering as well as graduate work in sanitary and hydraulic engineering. That sanitary engineering emphasis continues to this day as an integral part of the UT Civil Engineering undergraduate and graduate programs. In 1936 the sanitary engineering option of the Civil Engineering program was accredited by The Engineering Council for Professional Development (ECPD). The Master of Science degree in sanitary engineering was approved by the UT Graduate School in 1947 and in 1952 the Ph.D. degree in civil engineering was approved. Over the more than 113 years, the graduates of these engineering programs have provided leadership and continue to contribute significantly to the advancement of the sanitary/environmental engineering profession in the State of Texas, throughout the United States and internationally.

The September 8, 1900 hurricane wiped out half of the Galveston buildings and killed 8,000 to 10,000 people, the deadliest natural disaster in U.S. history. In 1902, an engineering commission of Henry Martyn Robert (author of Robert's Rules of Order), Alfred Noble (ASCE National President in 1903 who later helped determine the route of the Panama Canal), and Henry Clay Ripley made recommendations for a Galveston concrete seawall on wood pilings and extensive hydraulic-fill from elevations of 3–8 feet to a grade raising of 17 feet. Pictures of the 1900 hurricane destruction, relief efforts, grade raising, and seawall construction are included. On October 13, 2001, ASCE presented the Galveston U.S. Army Engineer District with a plaque designating the Galveston Seawall and Grade- Raising as a National Historical Civil Engineering Landmark (NHCEL).

The Lake Ontario — St. Lawrence River system is influenced by a dam spanning the St. Lawrence River between Cornwall, Ontario, and Massena, New York. The dam was built and subsequently operated in accordance with a 1952 Order of Approval, amended in 1956, issued by the International Joint Commission, a binational U.S.-Canada organization created by the Boundary Waters Treaty of 1909. In establishing the current operating regime, the existing Order of Approval considered uses of water for domestic and sanitary purposes, for navigation, and for hydropower. It also provided benefits for upstream shoreline property owners through reduced lake level fluctuations while providing protection for downstream property owners through provisions for considering water level and flow conditions that would have existed had the structure not been built. The International Joint Commission is considering whether or not to change the operating regime for the Lake Ontario — St. Lawrence River system, including the Order of Approval, to address such things as recreational boating interests and environmental issues and to take into account knowledge gained over the past 50 years and technological advances. This paper describes the Commission's decision process, from the establishment of a Study Board and Public Interest Advisory Group to conduct a five-year binational study, to consideration of independent review, obtaining public input, consulting with the U.S. and Canadian governments, leading to a Commission decision.

Conflicting targets and water use alternatives among different users and stakeholders is a major challenge in multi-purpose reservoir operation. In this study a GA-based optimization model is used for integrated long-term operation of a reservoir with water allocation and flood control objectives. The objective function of the optimization model is based on the Nash bargaining theory which can incorporate the utility functions of the decision makers and the water users as well as their relative authorities on the water allocation process. The model is applied to the Karkheh reservoir system in the southwestern part of Iran. The utility functions are based on the reliability of the allocated water to different sectors, the environmental water demand, water storage in the reservoir and the reliability of the reservoir for flood control. The results show that this model can be effectively used in optimal multi-purpose reservoir operation with conflicting objectives.

This study illustrates the value of game theoretic methods in water resources conflict resolution by the application of the Graph Model for Conflict Resolution (GMCR) to the Jordan River Conflict. The major objective of the paper is to show how GMCR can be readily applied to virtually any social conflict. The GMCR II decision support system, with its unique ability to handle socio-political conflicts, is used to model and analyze a generic version of this ongoing Middle-East conflict. The game model finds the equilibria of the game and suggests possible coalitions of conflicting parties.

The Tigris and the Euphrates cross a largely arid land and empty into the Persian Gulf through the largest natural marshes in southwestern Asia. From time immemorial, the Marshlands were a region in which a community of people made their homes and derived their livelihood and preserved a particular local culture closely linked to the marshes. As recently as 1990, these marshes constituted healthy, ecologically rich wetlands, teeming with aquatic life, animals adapted to marshes, and migratory birds. After the Marsh Arabs joined in the revolt against Saddam Hussein in 1991, he undertook to drain the marshes in order to bring these highly independent people under his control. The former marshes became barren, salt-encrusted land, and the Marsh Arabs were living as refugees in Iran and Iraq. No attempt was made to develop the diverted water. The destruction was a clear instance of ecocide, but an ecocide adopted as a means of committing genocide against the Marsh Arabs. After the fall of Saddam, the Marsh Arabs returned to the land and restored the flow of water by simply breaching the dams, dikes, and canals—with little or no attention to water quality concerns. Today about 50% of the marshes have been restored. In this paper, I shall examine the legal issues relating to the destruction and the restoration of the Iraqi marshes.

In this paper, a comprehensive investigation on application Artificial Neural Networks in long-term rainfall forecasting is presented. A variety of ANN-models have been developed to process and train a system with large scale climate signals for the summer precipitation spells. The summer monsoon is one of the most dynamic climate systems that controls rainfall variation in some Asian countries such as India and Pakistan and delivers a component of annual rainfall in these regions. The sum of rainfall during July, August and September is called summer monsoon rainfall. In order to quantify the effects of large scale climate signals on the precipitation in the study area, long-term records of SST (Sea Surface Temperature) and SLP (Sea Level Pressure) over Oman Sea, Arabian Sea and Indian Ocean have been examined. The SSTs over west coast of India as well as the SSTs over the Oman Sea shows a high correlation with monsoon rainfall in Iran. Also SLP over the Northern part of India shows a significant correlation with recorded rainfall at different points of the region. These signals can be used as useful predictors for monsoon rainfall at the southeastern part of Iran. The results show that considering a set of predictors developed in this study could significantly increase the accuracy of long-lead precipitation forecasting in the study area using ANN models.

This paper probes three kinds of institutional changes and their effect on water resources planning and management m China: the evolution of water price regulations, the evolution of regulations for fund raising of water resources engineering and the reformation of water right system. The idea of taking water as an economic good with greatly increased water price is beneficial for most water resource engineering projects; however, it has made some outstanding projects impossible to realize their planned performance. The main reason is that water demand to these projects under the water market is much lower than the predicted when the planning of the projects, which causes the capacity waste of those projects. Under the new investment regulations, local government should share the capital cost according to their share of benefit. For example, provinces and cities that share the water supplied by South to North Water Transfer Project should share the capital investment of the project according to their share of water quantity diverted. This investment regulation impacts the decision preference and planning process of large projects in the country. The emerging water right and market systems will certainly bring opportunities and also challenges to water resources planning and management in China. The planning and design of some projects may also be influenced by the possible changes of water right.

Prior to partition in 1947, the people who live to the East and West of the Indus River border that crosses between India and Pakistan used their shared river and its tributaries to sustain the region's farms, industries and cities. In recent years, Indians within the five Indus states and Pakistanis in its four Indus provinces are using more water, leading to deteriorating water quality and decreasing water availability. For over 40 years, the competition for the Indus' water between Pakistan and India has been moderated by a relatively stable Indus Water Treaty (IWT). In May 2005, however, a disagreement between the two countries over India's construction of a hydroelectric project on the Chenab River, an Indus tributary, was referred to a neutral third party for resolution. While both sides have adhered to the terms of the IWT in the past, rising demand for water in each nation could unsettle this stable relationship, as foreshadowed by the involvement of a third party for the first time in the treaty's history. The text of the IWT could allow each party to find flexibility to address rising demands. Given both the historic and economic significance of the Indus River for each nation, addressing these issues could benefit each side and prevent conflict.

The binational Rio Grande/Bravo basin, located in North America, is considered to be a highly water scarce region. The Physical Assessment project is a collaborative effort between technical and expert counterparts in Mexico and the United States that is aimed at exploring opportunities for improving management of the scarce water resources of the river through development of management scenarios. The Physical Assessment project is focused on creating management scenarios which fall within the current water allocation structure in the basin including treaties, compacts and water rights. To evaluate the hydrologic feasibility of possible water management scenarios, a hydrologic planning model is being constructed in the Water Evaluation and Planning system, or WEAP. The hydrologic and hydraulic information to support the model is provided from a relational Arc Hydro geodatabase which contains geographic, hydrologic, hydraulics and related data for the entire Rio Grande/Bravo basin.

The status of the mangrove ecosystem on the eastern part of the island of São Luis, Maranhão, Brazil, was assessed during summer and fall of 2005 by a scientific team. The mangroves on the study site cover an area of approximately 926 hectares. They are located in the northeastern Brazilian States of Maranhão, Pará, and Amapá, which represent the largest concentration of mangrove forests in the world. The scientific team compiled baseline information that was used to forecast trends in the temporal trajectory of the São Luis mangrove ecosystem; information included abiotic and biotic as well as socio-economic indicators. The team then developed an assessment matrix to formulate future scenarios of impacts on the mangrove ecosystem. The mangrove ecosystem of the study area was found to be subjected to abiotic, biotic and socio-economic stressors with varying degrees of magnitude. Human population growth, environmental awareness and local community support, among other considerations, should be part of any long-term strategy for a sustainable mangrove ecosystem and its associated resources.

In the Middle East and in the regions of North Africa, water is an element that links nations and people, regardless of their ethnic origin, religious or even the personal feelings they have for one another. In the coming years, this natural important resource may become a reason for war or peace, destruction or calming, separation or reconciliation. Even if diplomatic efforts are deployed and institutional arrangements established, the needs for water will remain; people will not stop from drinking, irrigating their lands or developing their industries. The only option that remains to the nations of this region will be to find a solution to deal with the problem of this rare resource in a cooperative way, based on techno-economic criteria as far as resources, availability, actual and future needs is concerned and this within an integrated and equitable water management context. The complexity of the region cannot tolerate simple, immediate and non planned solutions that may cause unforeseeable, brutal and uncontrolled reactions that may embrace the whole region of the Middle East. The UN Report entitled "Water for Life Water for People" 2003, has listed 263 international trans- boundary basins. Beyond their significance in terms of area and conflict potential, these basins: 1) Cover 45 % of the land surface of the earth 2) Effect 40 % of the world's population 3) Account for approximately 80 % of the global river flow 4) Cross political boundaries of 145 nations. The hydro-geographical setting of Lebanon (10,452 Km²) account for about 40 rivers and streams of which 12 are most important watercourses. The Lebanese territory has been subdivided into 5 major hydro-geographical basins managed by 5 water authorities newly created (2001) and expected to function within the spirit of Integrated Water Resources Management (IWRM) in contrast with the "traditional" fragmented and abolished 22 water authorities and 320 water irrigation commissions. A part of Lebanon's hydrological watercourses flow into neighboring countries crossing the Lebanese Southern, Northern and North Eastern borders. A closer look to the UN Report "Water for Life Water for People" 2003 shows that 3 trans-boundary watercourses implicate the Lebanese territory. Beyond their importance in terms of area and political impact consumed, a look at the number of countries that share the Jordan River basin (see Table 2) highlights the precarious setting of any simple and non equitable mechanisms for sharing water within the involved countries. Based on these complicated facts and patterns of harmonizing mechanism for sharing water, an example of cooperation within the context of hydro-diplomacy in the Middle East between Lebanon and Syria ended towards an equitable and sustainable management of the Orontus and Nahr el Kabir rivers based on the UN convention on non navigational uses of International Watercourses.

Cooperative game theory can be used for management of water resources in transboundary river basins. Applications of game theory which have been used for conflict analysis in water resources management include metagame analysis and graph models. These games are not considered classical game theory. These games allow strategies to evolve over time through repeated play and the players typically do not have communication prior to play. In cooperative game theory the players, or decision makers, have communication prior to the game and are allowed to make joint agreements. Cooperative games are considered non-zero-sum games where the costs and benefits of decisions are allocated to all players. Unlike metagames or graph models, the user must specify all possible strategy sequences that could occur. In a transboundary river basin setting, to generate the possible strategies, a water resources model is used to generate the payoffs from the sequence of strategies. These payoffs are then entered into a payoff matrix for calculations. In this paper, an application of cooperative game theory for the Syr Darya basin is presented.

Since 1960, the outflows of Lake Ontario have been controlled and water levels managed by the structures within the St. Lawrence Seaway and Hydropower Project. These operations have enabled the generation of hydroelectric power, commercial navigation from the Atlantic Ocean to the Great Lakes and benefits through a reduction of flooding of properties along the lake's shoreline. However, the resulting reduced range of levels negatively affected the lake's wetland diversity compared to that which existed pre-project. The recently completed International Lake Ontario-St. Lawrence River Study proposed alternative operational plans which improve conditions for all interests and increase ecological benefits, principally wetland diversity; creating no disproportionate loss to any interest. The Study used a Shared Vision Planning approach along with an Integrated Ecological Response Model to investigate alternative management plans and determine their impact in terms of environmental performance indicators. This paper describes the estimated impact that current lake level management has had on wetlands and selected biota and the alternative plans developed by the Study Board to improve conditions. It also describes the adaptive management procedures proposed to assure that the anticipated results would be fulfilled.

Lake Ontario is the most downstream of the Great Lakes that define part of the boundary between Canada and the United States. It receives its water from the four other Great Lakes as well as from its local watershed. It discharges water into the St. Lawrence River that flows northeastward past Montreal and Quebec into the Gulf of St. Lawrence and the Atlantic Ocean. The levels of Lake Ontario and the upper portion of the river and the flows and levels in the lower portion of the St. Lawrence River are regulated, to some extent, by the operation of the Moses Saunders Dam that separates these two river portions.

This paper reviews recent work by the Border International Water Quality Standards Committee of EWRI and summarizes some of the recent trends that either parallel or support the Committee's work products. The Committee is developing a major document revision that will add two appendices to the previously published "Comprehensive Transboundary International Water Quality Management Agreement". The new version is titled "Comprehensive Transboundary Water Quality Management Agreement with Guidelines for Development of Standards, Criteria and a Management Plan" which is described in previous papers. The document development follows the established process for ASCE standard. The purpose of the upcoming "Comprehensive Transboundary International Water Quality Management Agreement." is to provide a framework for bi- or multi-lateral agreements that form the policy and regulatory structure for establishing a partnership between sovereign countries or nations (Parties) to provide comprehensive water quality management of shared water resources along or across intergovernmental boundaries. This model agreement and the appendices will provide a step-by-step approach to implementation of an agreement of this type is based on the concept of shared sovereignty. It is appropriate only for those situations in which the Parties are prepared to relinquish a significant degree of sovereignty over their portion of the shared water resource. The two new appendices will focus on the Guidelines for Development of Standards, Criteria and Guidelines for Development of a Transboundary Water Quality Management Plan.

Climate-specific measures of crop water use of mature blueberry plantings could offer growers improved irrigation management. In contribution to improved irrigation management practices for Florida blueberry growers, this paper presents a crop coefficient for mature Southern highbush blueberry plants. Measures of crop water requirements were made using a water balance enabled by drainage lysimeters. Grower-controlled irrigation management is compared with a shorter, researcher-managed, timer-controlled schedule. A researcher-managed plot on a commercial blueberry farm is irrigated independently of the grower's fields, enabling comparison of crop ET and beneficial evaporated fractions, the ratio of water used for crop development to the gross irrigation diversion between grower-controlled and researcher-managed timer-controlled irrigation management. Four lysimeters in the researcher-managed plot and four lysimeters in a six acre plot of the grower's field were used to measure crop water use. Water balance durations range from 7 to 10 days. Lysimeter area corresponds closely to crop canopy area of mature plants. Irrigation inputs are measured by flowmeters, and precipitation inputs are measured by an onsite weather station that is also used to determine reference ET.

Irrigation scheduling is an important management practice for farmers who grow irrigated crops. Effective irrigation is possible by regular monitoring of soil water and crop development conditions in the field. However, this methodology requires frequent field visits and, consequently, it is time consuming. Computer simulation models can be an important aid for irrigation scheduling, as they integrate the soil-plant-atmosphere complex. The main objectives of this study were to determine the impact of different irrigation scheduling regimes on cotton and peanut growth and development and to evaluate the application of a crop simulation model as a tool for irrigation scheduling. Two experiments were conducted in four rainout shelters, located at the Griffin Campus of The University of Georgia, during 2005 and 2006. Cotton was grown in 2005 and peanut was grown in 2006. The CSM-CROPGRO-Cotton and CSM-CROPGRO-Peanut models were used to define the irrigation treatments by estimating the timing of irrigation and the amount of water to apply. The irrigation event was triggered when the actual soil water content in the effective root zone dropped below a specific threshold of the available water content (AWC) and then irrigation was applied until the soil water reached 100% of AWC. The irrigation treatments corresponded to 30%, 40%, 60% and 90% of the irrigation threshold (IT). The models require daily weather data, including maximum and minimum temperature, solar radiation and precipitation as input. Actual weather data were used until the current date and the daily weather data for the past 10 years were used to project until the end of the growing season. The cotton cultivar DP 555 BG/RR was planted on May 17, 2005 and the peanut cultivar Georgia Green was planted on May 22, 2006. For both experiments, the soil water content was monitored with Time-Domain-Reflectometry (TDR) and with a soil profile probe (PR2/6). The TDRs and PR2/6 probe were connected to data loggers. For both crops, growth analysis, including leaf area index (LAI), plant height and biomass, was conducted approximately every 18 days. Yield and yield components were obtained at final harvest. For cotton, the 30 and 40% IT treatments had significantly less number of bolls/m². The statistical analysis for lint yield showed that there were no significant differences between the 60 and 90% IT treatments. For cotton and peanut, low values of aboveground biomass at harvest and yield were found for the 30 and 40% IT treatments. The study showed that the dynamic crop growth models CSM-CROPGRO-Cotton and CSM-CROPGRO-Peanut can be used for irrigation scheduling, but a variable irrigation management depth needs to be incorporated in the model and a correct characterization of the soil properties is needed.

The restoration of meadow land using the pond and plug technique of gully elimination was performed in nine-mile segments along Last Chance Creek, Feather River Basin, California. In order to assess the impact of these restoration activities on water balance, it is crucial to estimate ET in a sparsely gauged watershed like Last Chance Creek watershed. As this watershed is covered mostly by pasture, shrub, riparian vegetation, and forest, it is difficult to apply the common ET estimation methods for croplands. In this presentation, a procedure to estimate ET from naturally vegetated land based on reconstructed atmospheric data and remote sensed information will be discussed. The ET from natural vegetation is mainly dictated by three factors: atmospheric conditions, vegetation conditions, and soil water conditions. The atmospheric conditions were reconstructed using a hydrodynamic atmospheric model. The vegetation pattern information, obtained by local survey, which may be at the best spatial resolution available, was combined with the satellite remote sensed data from MODIS (MOD15 and MYD15) in order to construct spatially and temporally varied LAI maps for the watershed. Using LAI and surface roughness height, the potential ET, based upon the reconstructed atmospheric conditions, was adjusted for every vegetation type. The soil water condition was estimated using a spatially averaged soil water flow model in which the soil heterogeneity at the subgrid scale was explicitly parameterized. It is shown that the ET over natural vegetation during the historical critical dry and wet period (1982–1993) in the watershed was successfully estimated and incorporated into the assessment.

Accurate determination of potential and reference evapotranspiration is essential to estimate water balances. In most standardized methods, such as the Penman-Monteith and Priestley-Taylor methods, net radiation is one of the most important forcing data. Unfortunately few stations measure net radiation. Instead, net radiation is typically calculated from solar radiation, ancillary climate variables, and albedo values derived from the literature. This research evaluates a series of methods used to calculate net radiation over different canopy surfaces. The four components of net radiation were measured at eight locations including urban, agricultural, rangeland, forest, wetland, and open water land types in central Florida. Data collected from January 2004 to December 2005 were used in this analysis. The results identify the most appropriate method to estimate net radiation and quantify net radiation and potential ET error estimates by method. Additionally, the impact of diurnal and seasonal albedo changes on net radiation calculations is examined.

Reference evapotranspiration (ET_o) has been used for irrigation scheduling and water management of urban landscapes from the publicly accessible weather networks by water governing districts and homeowners alike. However, most of these weather stations are located on small grass surfaces and does not meet the minimum fetch distance as required by the standard. The four parameters used in the ET_o calculations are temperature (T), relative humidity (RH), solar radiation (R_s) and wind speed (U). The solar radiation is the least influenced parameter by the local surface condition, while the wind speed is the most affected factor. Allen proposed that when the wind speed is higher than 2 m/s, the temperature and relative humidity measurements are not conditioned by the grass surface surrounding the station with adequate fetch as required by the standard, but by the fetch distance upwind of the weather station. When the wind speed is less than 2 m/s, mathematical equations have been developed to evaluate the influence of the upwind fetch distance on T and RH measurements. These equations show that the impact factor, fraction of vapor and sensible heat flux densities at height z contributed by fetch over upwind distance, varies with measurement height and fetch distance. The objectives of this study were to estimate the appropriate RH/T sensor height for various fetch distances using Gash's footprint model in urban areas. The impact of sensor height and fetch distance on reference ET calculations using the ASCE-EWRI Penman-Monteith equation with a grass reference were examined. In this experiment, five weather stations, one located on an ideal large grass reference surface in an agricultural region and four stations on non-ideal small grass surface in urban areas, were used to examine the impact of fetch. For each station, there are three RH/T sensors, located at approximately 0.5, 1.0 and 1.5 m. Solar radiation and wind speed are also measured at each station. The daily ET_o showed no difference at the three RH/T sensor heights, indicating that the ambient environment had little influence on the RH/T measurement in humid climate, even under non-ideal reference condition. However, more data need to be collected to assess the effect of fetch over an annual cycle.

Western United States history is inescapably tied to water. Water is the economic foundation of the fastest growing areas in the West. Federal, State, Tribal and local water conservation legislation often facilitates irrigation canal seepage reduction measures. From the All American canal in California to small lateral irrigation canals, seepage makes for intense, often heated discussion in droughty areas. Seven common canal seepage control alternatives are measured against four functional criteria that end users consider important for evaluating canal lining methods. These equally weighted functional criteria are: ease of maintenance, design life, total installed cost and ease of installation. The relative strengths and weaknesses of each alternative are discussed. These alternatives range from performing no lining improvements whatsoever to the use of asphaltic and polymeric geosynthetic barriers. EPDM polymeric geosynthetic barrier (a synthetic rubber) was found to most closely meet the end user's expectations for a canal liner.

A pressure-driven analysis has been developed to model residential irrigation systems. This approach models each sprinkler as an orifice with a free discharge. An individual sprinkler with supply piping is represented by a characteristic P-value. An equivalent characteristic P-value is used for multiple sprinklers with their supply piping in an individual residential landscape and an overall equivalent characteristic P-value for a junction in a distribution main to multiple residential landscapes. The pressure-flow relationship at a demand node is presented by means of hydraulically-aggregated junctions in the distribution main with a rotation factor for simultaneous operations. A general design methodology is summarized in the paper. The pressure-driven analysis has been successfully used in the City of Rockledge's reuse water system for on-demand flow forecasting. In comparison with test data, the analysis could predict the actual flow within 0.3% and 5.6% margins for two remote subdivisions. The predicted flows by demand-driven analysis were not in agreement with the measured flows.

The objective of this study was to assess the operational characteristics and performance of the Surface Energy Balance Algorithm for Land (SEBAL) model for estimating actual ET (ET_c) and other energy balance components, and mapping spatial distribution and seasonal variation of actual ET on a large scale in Great Plains climatic conditions. A total of seven cloud free Landsat images from May 2005 through October 2005 were processed to estimate the various components of energy balance equation and to determine the ET for the part of the Great Plains in the states of Nebraska and Kansas. The predictions from SEBAL model were compared with the Bowen Ratio Energy Balance System (BREBS) measured fluxes. The ET_c maps generated by model showed a very good progression of ET_c with time during the growing season in 2005 as the surface conditions continuously changed. The predictions for some surface energy fluxes were very good. SEBAL overestimated the soil heat flux as compared to BREBS. Local calibration of this flux significantly improved the predicted values. Overall, a very good correlation was found between the BREBS measured and SEBAL estimated ET_c for all images analyzed with a good r² of 0.73 and a low RMSD of 1 mm d^–1. The model was able to predict growing season cumulative daily corn ET reasonably well within 5% of measured values. While our results showed that SEBAL can be a viable tool to assess and quantify spatiotemporal distribution of ET on large scales as well as estimating surface energy fluxes, its operational assessment for estimating sensible heat flux and ET_c, especially during the drier periods needs further investigation.

A wetland mesocosm experiment was conducted in eastern N.C. to determine if organic matter (OM) addition to soils existing in ditches that are to be retrofitted into constructed wetlands would improve NO₃^–-N treatment. Not all soils are suitable for wetland substrate, so OM addition can provide a carbon and nutrient source to the wetland early in its development to enhance denitrification and biomass growth. Batch studies, with various initial NO₃^–-N concentrations were conducted in surface-flow wetland mesocosms. The results indicated that increasing the organic matter content of a Cape Fear loam soil from 50 g kg^–1 (5% d.w.) to 110 g kg^–1 (11% d.w.) enhanced NO₃^–-N wetland treatment efficiency in spring and summer batch studies, but increases to 160 g kg^–1 (16% d.w.) OM did not. Increased OM addition and biosolids to the soil significantly increased biomass growth in the second growing season, when compared to no OM addition. Based on the first-order kinetic constants for nitrate reduction calculated from these mesocosm studies, increased OM in the substrate will reduce the area required for wetlands constructed in ditches to treat nitrate-laden drainage water.

Successful restoration projects return functionality to stream corridors through proper design practices. The desired result is a dynamically stable dimension, pattern, and profile that resemble typical regional stream types. The Coastal Plain of the Southeastern United States contains many low gradient, sand bed streams with bottomland hardwood forested floodplains. Detailed analysis of existing and constructed streams is necessary to predict the type of dynamic equilibrium that can be expected in this region. The North Carolina Clean Water Management Trust Fund supported construction and research of a stream restoration project in the Core Creek watershed in the Lower Coastal Plain region of Eastern North Carolina. Researchers investigated sediment transport on the newly constructed channel using sediment budget techniques. The sediment budget used a series of intermittently surveyed, permanent cross sections to monitor channel stability and evolution. The Rosgen Classification system was used to communicate stream evolution patterns. The design stream was a sinuous E5 channel with a width to depth ratio of 11.1, valley slope of 0.1%, and well developed flood plain. Following construction, the average top width of the channel widened while the average depth decreased, resulting in a higher than designed W/D ratio. The instability in the banks was mostly due to geotechnical forces. As vegetation stabilized banks, the cross sections deepened and tended more to an E5 classification. The final average channel width was 4.74 m and average depth 0.4 m, resulting in a width to depth ratio of 11.8. Data illustrate the establishment of beneficial scour pools and stable riffles. Sediment loss was restricted to pools. Recent large discharge events have resulted in deposition and channel narrowing. Results indicated the restored reach was able to self-adjust based on incoming sediment loads to a stable dimension, pattern, and profile with minimal anthropogenic maintenance. Vegetation establishment played a key role in channel stabilization. Future work includes evaluation of bank full flow return interval, establishment of a sediment rating curve, and calculation of the effective discharge.

Two stream restoration projects were recently designed and constructed in the coastal plain of NC. Several popular design approaches were implemented to develop plan parameters. Traditional engineering methods, natural channel design methods, and analytical approaches were utilized. The results of each approach were compiled for comparison and to improve design confidence. This paper includes a description of the methods employed, the limitations encountered, and an evaluation of the results. Each method presents challenges in terms of data collection, effort, and the experience required. Information on these limitations should be incorporated in design approach and application decisions. Based on initial findings, it appears that design differences for small streams with relatively stable watersheds may not exceed expected variability. However, this may not be the case for larger streams as differences increased with watershed size and complexity. It is suggested that completing similar initial estimates will improve design decisions, confidence, and reduce risk. As the science of stream restoration progresses, more quantitative comparisons of this type will provide designers with the information needed to guide complex approach decisions.

Rural watersheds in the Midwest Region of the United States are dominated by agricultural land uses that often incorporate subsurface drainage improvements. Subsurface drainage systems discharge into headwater channels that have been deepened and straightened to facilitate the flow of water from drainage outlets and to lessen flooding of agricultural fields. Natural adjustments, within these large modified or constructed ditch, often establish fluvial channels, henceforth called inset channels. These inset channels have small stable floodplains, called benches, that form by vertical accretions of deposited sediment that then vegetate with grasses (Figure 1). However, rarely do these systems exhibit out of bank flows onto a broad floodplain and, in many cases, when stable benches form they are periodically removed by human maintenance activities. Channel maintenance is performed to remove woody vegetation and deposited sediment, stabilize bank slopes, and to address toe scour problems. These routine maintenance activities are costly, disrupt the existing ecology, and sometimes adversely impact water quality. This manuscript provides a summary of two recently completed doctoral studies and several manuscripts based on these studies. The goals in reporting this information are to inform the reader on: (1) the factors that influence the establishment of inset channels and benches in agricultural ditches; (2) a method for modifying an agricultural ditch to a two stage geometry as an alternative to conventional drainage; and (3) research that is being conducted to evaluate the water quality and ecological benefits of ditches with an inset channel and benches.

Irrigation systems need to become more efficient to minimize the use of limited water resources while maintaining landscapes of acceptable quality to consumers. This manuscript gives a preliminary report on the evaluation of three commercially available evapotranspiration (ET) based controllers in residential landscaped plots with respect to irrigation application and landscape quality compared to a homeowner irrigation schedule. The irrigation treatments were as follows: T1, Weathermatic Smart Line Series controller; T2, Toro Intelli-sense; T3, ETwater Smart Controller 100; T4, a time-based treatment; and T5, 60% of T4. This paper reports preliminary results from May 25, 2006 to November 30, 2006. T1 overestimated ETo by 32%, but applied less water than all other treatments during the summer season. Water savings occurred even though ETo was overestimated due to an underestimation of the crop coefficient for warm season turfgrass programmed into the controller (0.60) and due to frequent irrigation event bypass during the rainy summer season. The Weathermatic controller applied 11% and 14% less water than the theoretical gross irrigation requirement during the summer and fall seasons, respectively. The Toro Intelli-sense controller applied 126 mm in the fall, which was 40% less than theoretical requirements, and had the most accurate ETo of all the controllers. The ET water controller overestimated ETo by 7% and applied 63% more irrigation water than was required theoretically. During this preliminary testing, the ET controllers did not result in turf quality below acceptable levels.

A variety of commercially available technologies for reducing residential irrigation water use are available to homeowners. These technologies include soil moisture sensors, rain sensors and evapotranspiration (ET) based controllers. The purpose of this research was to evaluate the effectiveness of these various technologies based on irrigation applied and turf grass quality measurements. Testing was performed on two types of soil moisture sensors (SMS, LawnLogic® and the Acclima Digital TDT® RS500) at low, medium, and high soil moisture threshold settings. Mini-Clik® rain sensors comprised seven time-based treatments, with three treatments pre-set for 3 mm of rainfall and the remaining 4 rain sensor treatments had sensors pre-set to bypass irrigation for 6 mm of rainfall. Two ET controllers were also tested, the Toro Intelli-Sense controller and the Rain Bird® ET Manager^TM. A time-based treatment with two days of irrigation per week and no rain sensor (2-WORS) was established as a comparison. SMS-based treatments resulted in 0–63% reductions in water use compared to 2-WORS. Rain sensor treatments resulted in 7–33% reductions in water use. ET-based irrigation resulted in 36% to 59% reductions in water use compared to 2-WORS. The SMS treatments at the low threshold settings resulted in high water savings, but reduced turf quality to unacceptable levels. The medium threshold setting SMS-based, time-based and both of the ET-based treatments produced good turf grass quality while reducing irrigation water use compared to 2-WORS. Savings for the medium SMS-based systems ranged from 11–28%.

The efficient use of water for containerized plant production in Florida has been a major concern for many years. Today, this concern is greater than before because of the diminishing fresh water resources and increasing water quality problems in many areas. In Florida, withdrawal of fresh water for irrigation, including container-grown ornamental plants, represents the largest of the state's water pumping demands. Agriculture in Florida uses 12.3 million cubic meters of fresh water meters per day. The typical daily application of fresh water used by the container nurseries is on average 7 mm day which amounts to 250 m³⋅ha day^–1. Traditionally container-grown ornamental plants have been overhead irrigated, yet only 20% of the water applied by this system is actually used by the plant. For proper plant development containers often require significant amount of space between containers, which leads to increased runoff of unused irrigation water. Concerns of depletion and contamination of water sources by nursery and other industries has initiated programs for water conservation and regulation standards. An alternative to overhead irrigation is micro-irrigation, use of spray stakes or drippers, which has been shown to reduce runoff and nutrient loss while maintaining equal or improved plant growth. A system that can produce further reduction on water use is the Multi-pot Box System Water (MPBS). A study using microirrigation together with the MBPS showed reduced water run-off and optimized irrigation efficiency on the production of a woody ornamental. This paper will (1) analyze the efficiency of the MPBS compared to a conventional system used in nurseries growing containerized ornamentals, (2) measure the amount of water used by both systems, and the quality of the runoff water, and (3) compare growth indicators of seven species of ornamentals grown under both systems.

Artificial turfgrass is a synthetic material made to resemble real grass. A new generation of synthetic turfgrass is made of plastics with different composite materials, and is supported by a sand and/or rubber infill material and subsurface base layer. Synthetic turfgrass is being increasingly used on many athletic fields, such as soccer, football and rugby, as well as in urban landscapes. It is superior to natural grass in aspects, such as lower maintenance, no irrigation required, and surface uniformity. However, high temperatures on synthetic turfgrass surface during hot weather may be dangerous and could result in heat related health problems, such as heat stroke. The objective of this study was to evaluate the temperature increase among different synthetic turfgrass types and to predict temperature increase on the synthetic turfgrass surfaces. In this study, four types of synthetic turf grasses (1 – 4) with four infill materials and base layers (A – D) were installed in central Florida, surrounded by large irrigated natural grass fields. Temperature measurements were taken at 23.5 cm above the ground and 5 cm below the ground. The results indicated that there were no differences in air temperatures above the ground between the synthetic turfgrass and the natural turfgrass, due to the small size of the plots and the high wind speed during the daytime. The temperature below the surface (base temperature) for the synthetic turfgrass was always higher than the natural surfaces at noon time. The base temperature differences between the two surfaces were higher in July and August and lower in November. Overall, the infill temperature difference increased with an increase of the depth of the base layer and the color of synthetic turfgrass. Base temperature increase on synthetic turfgrass (T_syn) was linearly related to the incoming solar radiation (R_s). Relationships based on solar radiation and temperature on natural surfaces (T_nat) (both natural grass and bare soil surface) were developed for all units (T_syn – T_nat = a R_s + b) so that the temperature increase on synthetic turfgrass could be predicted.

Depletion of the Ogalalla Aquifer and increasing energy costs reduce profit margins makeing management strategies more critical. Management strategies evaluated include: 1) utilizing measurement of available water to determine the optimal irrigation to maximize the returns to irrigation, and 2) using the Percent Potential Evapotranspiration (PPET) to determine the optimal irrigation to maximize returns. The strategies are evaluated under average, first quartile, and fourth quartile levels of September through June precipitation as measured at the Amarillo International Airport. Both indicate that under average precipitation returns to irrigation are only positive for combinations of high crop prices and low energy costs. With above average precipitation costs increase more rapidly than revenues resulting in a reduction in net profit. When precipitation is in the fourth quartile returns to irrigation are greatly increased. The criterion based on available water indicates higher irrigation levels and higher returns to irrigation than the method utilizing PPET.

Deficit irrigation commonly is used in regions with reduced or limited irrigation capacity to increase water use efficiency (WUE). This research measured sorghum (Sorghum bicolor L. Moench) water use (ET) and yield so WUE could be determined. Two precision weighing lysimeters were used to accurately measure sorghum ET from a fully irrigated field (FULL) and a deficit irrigated field (DI; ~50% irrigation) that was irrigated by a lateral-move sprinkler system at Bushland, TX in 1993. Sorghum ET decreased 10% from 621 mm to 560 mm with a 48% decline in irrigation. WUE for both grain and dry matter increased slightly with DI but seed mass, and harvest index were unaffected. Sorghum extracted soil water mainly above 1.2 m in the Pullman soil profile if well watered, but DI sorghum extracted soil water to 1.7 m. Sprinkler DI beginning with a nearly full soil water content profile permitted the crop to better exploit the soil profile water and minimize soil water deficit effects on crop yield in a year with typical summer rainfall for Bushland (~210 mm) such that yield was not reduced by DI.

More than 90% of the water used in agriculture in the High Plains area comes from the Ogallala Aquifer. From 1994 to 2004, the aquifer declined at an average of 1.28 feet per year. Adding to the problem is the low recharge rate of the aquifer in the High Plains area. Declining availability of water from the Ogallala Aquifer in the Texas Panhandle has forced the water management and conservation authorities to find viable policy options to extend life of the Ogallala Aquifer without affecting regional economy. The results from each policy alternative are compared to evaluate the effectiveness of each policy in conserving water, the changes in producer revenues and the usage of resources for each county and for the overall region, and the economic impacts of each policy. The analysis can be used to help policy makers determine the overall impact of each policy under consideration, both in terms of the effectiveness in conserving groundwater in the Texas Panhandle and the economic costs at the farm, community, county, and regional level. The rural communities where agriculture is most reliant on irrigation will be the most affected by the policy, while urban communities and those communities in counties that are less reliant on irrigation will absorb the change more easily. All of these concerns must be addressed when deciding on any policy designed to restrict water used for irrigation.

The reduction in the availability of irrigation water and the increase in pumping costs resulting from the decline in the Ogallala Aquifer make management decisions more critical for the survival of the farm firm and the success of the agricultural sector in the Texas Panhandle. The increased profitability from cotton is a major reason for the expansion of cotton production in the area. Cotton yield-water response functions are estimated. The response functions are then transferred into value functions and combined with an irrigation energy cost function to determine the profit maximizing irrigation management strategy. The estimation of response functions based on the availability of water in the Ogallala aquifer provides insight into the different management decisions that are faced by the area producers. The analysis for natural gas prices between $6.50 and $11 per mcf and cotton between $0.35 and $0.70 per pound indicate that the amount of water needed to apply increases as the price of cotton increases. Conversely, for a fixed price of cotton the optimal water application rate declines as the price of natural gas increases.

Inertial attenuators are massive concrete blocks, aligned along the edge of the pavement to form barrier walls for traffic safety in construction zones. During heavy storm events it is extremely important to provide for adequate drainage of roadway runoff accumulating along these walls, so that water does not spread back into driving lanes, becoming a hazard. This paper presents a simple method to estimate flow and spread which has been implemented as a computer program to assist in the evaluation of the performance of the barrier wall system.

A drainage ditch near Laney High School in Wilmington, N.C., designed to collect runoff from athletic fields and parking lots and deliver it to Smith Creek, was converted to a constructed wetland in August 2005: The approximately 0.1 ha wetland collects and treats drainage water from a 12 ha watershed, 2.4 ha of which is impervious surface. The wetland was designed with a variety of elevation features and planted with over 15 species of wetland plants, to encourage sedimentation, biogeochemical transformations of nutrients associated with runoff, and ecological diversity. Retention times are estimated to be 3–4 days. As of summer 2006, the wetland was vegetated and on-line. Preliminary nutrient data indicate a 50% reduction in TN and TP concentrations, and a 40% reduction in TSS.

The unit hydrograph is a well-documented method for predicting the runoff hydrograph of a watershed given an excess rainfall hyetograph. Watershed-specific unit hydrographs are parameterized by some conceptual time such as time to peak runoff or time of concentration. Estimation of time parameters when paired rainfall and runoff observations are available is reasonably straightforward. In the absence of paired observations, the parameters are estimated from regression equations that relate unit hydrograph behavior to watershed physical characteristics such as area, slope, and land use. This study performed an exploratory assessment of a particle tracking (PT) method to estimate unit hydrograph timing parameters directly from a digital elevation model (DEM) instead of the regression approach. The PT method was used to estimate the unit-hydrograph timing parameters of 135 selected small watersheds in Texas using a DEM of each watershed, and an assumed characteristic velocity to generate a watershed-specific unit-hydrograph. The study watersheds have drainage areas ranging from approximately 0.25 to 150 square miles, main channel lengths ranging from approximately 1 to 50 miles, and dimensionless main channel slopes between approximately 0.0002 and 0.02. The selected watersheds include coastal plains as well as inland hilly regions. Paired rainfall-runoff data for over 2,600 storms were compiled; these provide actual observations to test the performance of the PT model.

This conference paper summarizes the results of a design oriented investigation in which a trashrack was designed to reduce the formation of vortices upstream of a submerged intake of an existing facility. A 1:15 hydraulic model was built and tests were conducted until a technical solution was found. The possibility of increasing the discharge maintaining approximately the same water level, led the investigators to find the best way to reduce vortex formation upstream of a submerged intake. Comparisons are made with the studies summarized in ASCE/EPRI. It was concluded that placing an appropriately designed trashrack significantly reduces vortex formation and air entrainment at the submerged inlet.

Agenda 21 of the 1992 UN Earth Summit on Environment and Development called for the development of new ways to measure and assess progress toward sustainable development. The nation needs a framework for tracking and understanding changes to the health of its fresh and coastal waters, surface and groundwater, wetlands and watersheds. It also needs a methodology for understanding the implications of these long term changes for ecosystems, communities and businesses. The Sustainable Water Resources Roundtable, continues to work on these problems. The paper begins by describing the conceptual foundations that have been developed to aid in understanding sustainability. We recognize the importance of the 1987 Brundtland Commission definition, which relies on maintaining equity between generations to help define terms. Sustainable solutions to water resources problems can be found if people thoroughly understand the issues and how each aspect of the society contributes to them. When considering key questions about water sustainability, some important technical problems such as scale and geographic patterns immediately arise. Certain kinds of measures and indicators may be good for tracking national level phenomena, but questions may arise about how this kind of data relates to smaller geographic areas within the nation. One objective of this paper is to address the importance of scale issues and geographic patterns and how they may influence the formulation of key water sustainability indicators. By presenting statistics from which indicators are developed in graphical form, the paper highlights several available studies that have proved to be promising in generating concrete results for developing water sustainability indicators at various scales.

Hydrologically, Georgia is a complex state. In addition, growth patterns are increasing water demands in areas which are already experiencing water shortages. Recent droughts have underscored water management concerns. To effectively address the water challenges facing the state, Georgia has undertaken development of a comprehensive state water management plan. The process adopted included a 15 month legislative study committee effort to explore the issues and to determine how a plan should be developed. Some 42 water-related issues were considered by the study committee, including water rights, interbasin transfers, agricultural water monitoring and reporting, and protecting water quality. Legislation introduced following the study committee's effort lead to heated debate during the 2003 session of the General Assembly, primarily over water rights, but the water planning legislation did not pass. Legislation was then enacted in 2004 directing the Environmental Protection Division of the Georgia Department of Natural Resources to develop a plan by July 2007. The first iteration of the plan focuses on state policy issues. The draft plan is to be reviewed by the Georgia Water Council composed of key legislators, legislative appointees, and the heads of state agencies with water related responsibilities. It will then be considered by the Georgia General Assembly during the 2008 legislative session. Although regional planning has been undertaken in three areas currently facing water problems, the next step in the planning process is expected to focus on regional planning statewide.

Integrated Water Resources Management (IWRM) is a process through which a new paradigm for management and governance of water resources can be implemented to ensure sustainability of natural resources. The State of Florida has been proactive in the implementation of IWRM principles, primarily through the creation of five Water Management Districts (WMDs) and other state agencies. The South Florida Water Management District (SFWMD), the largest WMD, is an agency of the State of Florida that has primary responsibility for management of water resources in a 16-county region that extends from just south of Orlando to Florida Bay. The agency's mission today is to manage and protect water resources of the region by balancing and improving water quality, flood control, natural systems, and water supply. This paper discusses how IWRM principles have been implemented for sustainability of water resources in South Florida while meeting the future needs of the agricultural, environmental and urban sectors. In particular, the emphasis on environmental restoration and protection, a key strategic objective in IWRM, is elaborated through the presentation of two large-scale water resources projects currently being implemented.

Integrated policy, planning, and management of water resources and energy systems can provide important opportunities. While both energy and water managers have used integrated planning approaches for decades, the broader integration of water and energy management is a relatively new and exciting policy area. Water and energy systems are interconnected in several important ways. Developed water systems provide energy (e.g. through hydropower), and they consume energy, primarily through pumping and thermal processes. Many energy systems require energy for cooling and other purposes. The focus of this paper is on energy inputs to water systems. Critical elements of water infrastructure systems and certain uses are energy intensive. Moving water over distances and elevation gains, treating and distributing it, meeting end-uses for various purposes, and collecting and treating the resulting wastewater, accounts for one of the largest uses of electrical energy in some areas. For example, estimates by the California Energy Commission indicate that 19% of the state's electricity use, and 33% of natural gas use (excluding power plants), is devoted to water use. Examples of new approaches to the integration of water and energy planning, including policy processes at the California Energy Commission, Public Utilities Commission, and Department of Water Resources are discussed. Current methodologies for accounting for embedded energy, from initial extraction through treatment, distribution, end-use, wastewater treatment and discharge, are reviewed. New approaches to institutional collaboration between energy and water management authorities and providers are also discussed.

While at the forefront of providing a comprehensive approach to managing flood threats in the mid-20th century, there is increasingly substantial evidence that the present approach of the United States is not sustainable from perspectives of public safety and economic and environmental consequences. Several observations can be made: (1) current floodplain management is unsustainable as flood damage is increasing, more lives continue to be threatened, and floodplain ecological functions degraded; (2) the nexus of Federal programs and local decision making coupled with cost sharing required for USACE projects are resulting in un-sustainable urban development in floodplains; (3) better synchronization of Federal, state, and local government policies and programs is required to stem the tide; and (4) optimal social investment in flood reduction requires a comprehensive and integrated perspective wherein levels of flood protection, land use, and residual risk management are tailored to site-specific conditions.

Water will remain a central issue for the sustainability of societies, ecosystems and economies around the world for the rest of our lives. Yet, in the United States and elsewhere, no single organization has the mission or mandate to address the full spectrum of water resource issues. The resultant fragmentation of responsibility brought about the formation of the Sustainable Water Resources Roundtable (SWRR). To make clear how broad water resource sustainability issues are, I will present examples of how we in SWRR attempt to raise awareness of the importance of water sustainability. We start with the "big picture" of water on Earth then the point is made simply that there are four main pressing issues related to water sustainability that vary with place: 1) Many places don't have enough water to meet current and projected uses, 2) Many places occasionally have far too much water, 3) Many places have dirty water, and 4) Many places are a water habitat. To address these areas and study their interrelationships, the SWRR brings together participants from federal, state, and local governments, corporations, non-profits and academia to advance the knowledge and decision-making needed to sustain the nation's water resources. Just as the participants in SWRR represent a wide range of interests and responsibilities related to water resources, we hope that SWRR's work is useful to a wide and diverse audience. To this end, participation in SWRR by interested people and organizations is encouraged.

The South Florida Water Management District (SFWMD or District) is currently developing a new Regional Simulation Model (RSM) that simulates the integrated coupled movement and distribution of groundwater, and surface water through the canal networks and water control structures in south Florida. In this paper the RSM is applied to Palm Beach County, Florida. These hydrologic components are primarily solved using the hydrologic simulation engine (HSE) of the model code. Likewise, the operations of the canal water control structures (pumps, gated culverts, gated spillways and weirs) present in the model domain are simulated using the management simulation engine (MSE) of the RSM. The MSE consists of a multi-level control scheme which encompasses the local control of a hydraulic structure by the imposition of flow and/or stage constraints on the individual modeled water control structures, as well as the coordinated sub-regional control of multiple structures. The entire code architecture was based on object-oriented design and concepts. The model performance of the HSE alone, with imposed historical boundary conditions and no MSE operations, will be evaluated by providing comparison plots between model simulated stages and discharges versus historical data as well as model output from the South Florida Water Management Model (SFWMM) — a legacy regional simulation model for the same area. Model performance will also be evaluated by running the model with the MSE operations also in place and by checking the simulated results for reasonableness. A test bed representing a subset of the entire modeling domain was created for Palm Beach County, Florida in order to understand the interaction between the hydrology and management aspects of the area.