Managing Watersheds for Human and Natural Impacts: Engineering, Ecological, and Economic Challenges

The Santa Clara Valley Water District (District) conducts annual stream maintenance activities such as sediment removal, vegetation management, bank protection, and minor maintenance to ensure that watersheds within Santa Clara County are appropriately managed. In 2002, the District obtained multi-year permits from regulatory agencies such as the California Regional Water Quality Control Boards (San Francisco Bay and Central Coast Regions), US Army Corps of Engineers (Corps), California Department of Fish and Game (CDFG), and Bay Conservation and Development Corporation (BCDC). Biological Opinions (BO's) on the multi-year stream maintenance program (SMP) were issued by the National Marine Fisheries Service, and US Fish and Wildlife Service. Most permits have been issued for 10 years subject to a five year revision if necessary. Program oversight is also provided by the US Environmental Protection Agency (EPA), nongovernmental organizations (NGOs), and concerned citizens. The permits specify that stream maintenance is implemented using a standard, pre-approved set of Best Management Practices (BMPs), The BMPs are designed to minimize the environmental impact of stream maintenance activities through pre-construction biological surveys, sediment characterization, water quality monitoring, and restricted work windows. The District has implemented the multi-year stream maintenance program (SMP) since August 2002. Several benefits have realized since program implementation. These include standard and consistent BMPs, pre-approved erosion repair, reduced planning and permitting cost, enhanced mitigation, greater time for field work, and continuous improvement through a Lessons Learned Adaptive Management process. This paper will describe the BMPs used to minimize impact, resource conservation protocols developed, and implementation process at the District. Key benefits of the program and challenges faced during implementation will also be discussed.

New Jersey has implemented a "Smart Growth" policy which encourages growth through re-development of areas already substantially developed and discourages development within the more rural and environmentally sensitive areas of the State. A primary objective of this policy is protection of the State's water resources. In addition, New Jersey now requires water quality treatment of stormwater runoff as part of it's response to EPA's Phase II implementation of the Clean Water Act. The Borough of Berlin in Camden County, New Jersey is designated by the State Plan Policy Map as a Metropolitan Planning Area targeted for future development and growth. The New Jersey Department of Transportation has proposed needed improvements to accommodate this growth. The improvements were designed to alleviate traffic congestion within the Borough, meet future traffic needs for the region, alleviate existing flooding problems, and improve stormwater runoff quality. Berlin is located at the headwaters of the Great Egg Harbor River, a high quality and high value stream that is designated as a Wild and Scenic River by the National Park Service. The project offered an ideal opportunity to merge the goals of both watershed protection and Smart Growth. Instead of sacrificing valuable land within a designated growth area for on-site stormwater management, a regional watershed-based approach was pursued. A suitable site was selected which will provide water quality treatment for a 0.9 square kilometer portion of an urbanized watershed, supply much-needed flood relief, and include the creation of wetlands to meet the regulatory requirements for compensatory mitigation. The multi-purpose regional facility will include a 0.850 ha stormwater wet pond/wetland system which meets numerous and sometimes conflicting requirements for water quality treatment, wetland mitigation, and flood control.

The Merrimack River is one of New England's major waterways, with a basin area in excess of 5,000 square miles. The headwaters originate in the White Mountains of New Hampshire, and the river discharges to the Atlantic Ocean at Newburyport, Massachusetts. The river and its tributaries support numerous beneficial uses, including water supply, recreation, aquatic habitat, and hydropower. A broad array of pollutants (bacteria, nutrients, and metals) has impaired the water quality in portions of the watershed and hence the attainment of these beneficial uses is often restricted. Much of the abatement emphasis has focused on reducing the magnitude and frequency of combined sewer overflows (CSOs) from five communities who have jointly sponsored this study in association with the U.S. Army Corps of Engineers: Manchester and Nashua in New Hampshire, and Lowell, Haverhill and the Greater Lawrence Sanitary District in Massachusetts. Until now, little scientific information has been available to compare the benefits of CSO abatement to other forms of river restoration and management in the context of instream water quality and attainment of beneficial uses. This study is aimed at identifying the sensitivity of the river to point-source and diffuse pollution, as measured by incremental improvements in water quality and use attainability with associated incremental levels of targeted abatement and restoration investments. The study conclusions will be based on comprehensive instream monitoring of approximately 135 kilometers of the mainstem river and predictive simulation models used to evaluate likely responses to abatement of CSOs, wastewater treatment plant effluent, stormwater runoff (urban and rural), and alternative dam operations. The outcome will be a comprehensive watershed management plan that will be used by the five sponsoring communities to plan, evaluate, and negotiate the allocation of expenditures with state and federal regulatory agencies.

The Blackstone River Watershed covers approximately 475 mi² in central Massachusetts and northern Rhode Island. Its headwaters are composed largely of the urban and industrialized areas of Worcester, Massachusetts, the third largest city in New England. The river played a key role in the industrialization of the northeast, at one point having one dam for every one mile of river. The impact of these impoundments on contaminant fate and transport, in particular their affect on propagation of improvements in upstream water quality to downstream reaches, is not well understood. The Blackstone thus represents a key case study for understanding watersheds with a history of industrialization and heavy suburban development. While already a stressed environment, the Blackstone faces additional degradation due to development pressures. The following paper presents a basin-wide analysis of pollutant sources and sinks within the Blackstone River watershed. Data collected during the Blackstone River Initiative (BRI) was used to analyze spatial trends in water quality along the river during wet and dry weather monitoring. Loads were compared to consecutive stations along the river to determine any potential sources or sinks between the stations as well as differences in water quality behavior between wet and dry weather conditions. Additional analysis was conducted to determine the relative loads of point and nonpoint source pollution to the Blackstone River under current and future conditions.

It is widely known that micro-organisms such as bacteria (for example, E. coli), Giardia (often associated with beaver), and Cryptosporidium (sometimes associated with pets, livestock, and wildlife) can enter streams during rain and snowmelt events. It is difficult, however, to accurately determine the magnitude and timing of transport during such events. In addition, accurately identifying the sources of these contaminants is a challenge. Hence, the organizations responsible for public water supplies, outdoor recreation, and environmental quality face substantial challenges in their efforts to protect public health. Microbial and water-quality measurements were collected during storm events under a variety of meteorological and land-use conditions in order to 1) identify risk of Cryptosporidium oocysts, Giardia cysts and other constituents, including microbial indicator organisms, entering surface waters from various land uses during periods of surface runoff; and 2) optimize storm sampling procedures for these parameters. The resulting database consists of wet weather transport data for twenty-one distinct storm events and three dry weather spatial basin sampling events. Insights gained on the prevalence and transport characteristics of the monitored parameters are discussed.

Federal and state regulatory programs in the Chesapeake Bay watershed require wetland mitigation to obtain a permit for wetland impacts. The loss of wetlands in a watershed through permitted activities diminishes its capacity to perform important habitat, water retention and dissipation, and biogeochemical cycling functions. Past attempts at wetland mitigation have produced wetlands that meet the three parameters (a predominance of wetland plants, wetland hydrology, and wetland soils) of a jurisdictional wetland, but little thought was put into whether the mitigation site was providing similar wetland functions to those wetlands impacted. Current research on wetland hydrogeomorphic (HGM) setting as well as HGM functional assessment models and other functional assessment approaches have provided incite on important characteristics that allow wetlands to provide certain functions. These characteristics are starting to be incorporated into wetland restoration and creation site design in hope that the mitigation site will not just mitigate for acreage, but also mitigate for loss of wetland function. Criteria for proper wetland mitigation design incorporate appropriate HGM setting, ability to reproduce hydroperiod and hydrodynamics, inputs of organic matter in forms that are partially decomposed and as coarse woody debris, macro- and micro-topography, and other characteristics that affect specific wetland functions. Mitigation criteria can be adjusted to address problems in a watershed by concentrating on characteristics that affect wetland functions that can help alleviate that problem.

Wetland functions are the characteristic activities (biological, chemical, and physical processes) that occur in these ecosystems. Functional assessment models are used to quantify the functional capacity of individual wetlands. The Hydrogeomorphic (HGM) Approach to functional assessment of wetlands classifies wetlands to the regional subclass level and then creates a model for an individual subclass in a given geographic area. An HGM model is essentially a functional profile that describes the physical, chemical, and biological characteristics of wetlands in the regional subclass, identifies those functions that are most likely to be performed on a sustained basis, and addresses landscape and ecosystem attributes that can be expected to influence each targeted function. The HGM Approach does not assign absolute values to functional capacity. Instead it rates functional capacity for a given wetland relative to reference standards-the highest level of functional capacity exhibited by wetlands in the regional subclass. Reference standards are established by assessment of wetlands that exhibit those attributes consistent with maximum sustained functional capacity. The HGM Approach is presently being applied to Piedmont slope wetlands in the Mid-Atlantic Region.

A number of tributaries of the Chesapeake Bay have a large number of dairy herds. Most of the dairy production is in the Susquehanna River, Shenandoah River and Potomac River tributaries. Typical manure handling methods in the watershed today are daily spread, solid manure handling with bedding and storage, scrape and storage in a tank or basin and a lagoon and flush system. New manure management technology needs to be adopted by the dairy industry to meet the new tributary strategies. Solids separation has the potential for reducing nutrients. The separated solids can be composted and be used for bedding or sold. Solids separation has the potential to remove 30% to 50% of the N and P from the manure stream. Anaerobic digestion has promise for large dairy farms in the future. Studies have shown with 800 or more cows make anaerobic digestion economically feasible. Composting is an established on farm manure practice that could be used by small or large farms. There is a need to implement it on a wide basis in the watershed. Sequencing batch reactors and integrated manure systems also have the potential for reducing nutrients and have been tested on a number of farms. Manipulating N and P in feed has the potential for reducing nutrient excretion. Using multiple strategies to improve nutrient utilization, N and P feeding could be reduced by 30 to 40%.

In 1998, the State of Delaware implemented a Harmful Algal Bloom (HAB) Surveillance Program in the Delaware Inland Bays. This program was motivated by several large, prominent fish kills that were attributed to algal blooms possibly caused from years of nutrient runoff from watersheds. To address the need for cost effective, real-time surveillance in water bodies at high risk, research over the past three years has led to the development of an inexpensive remote monitoring system that is capable collecting data throughout the entire depth of a water body. As configured, the monitoring system can measure as many as fourteen water quality and meteorological variables. The resulting information gives a complete snapshot of important water quality data—over a period of time, the data provides a more comprehensive understanding of water quality changes in a body of water throughout the entire depth. In addition, the monitoring station is equipped with cellular telemetry which transmits the data to a host computer that can broadcast the data on the web in real time; data can also be processed and sent to a list of scientists and other personnel for further analysis. This technology provides a unique and effective means to monitor estuaries and watersheds with high temporal resolution, which is critical for effective assessment of water quality conditions that can lead to algal bloom detection. The continuously recorded results from the monitoring stations will promote a better understanding of the influences of nutrient enrichment from watersheds on algal bloom dynamics, assist in determining the temporal relationships between HABs and shellfish health/toxin contamination, and provide an early warning system for the detection of algal blooms in several of Delaware's prime recreational waters.

In October 2002, Baltimore City and Baltimore County, Maryland signed a historic Watershed Agreement that unified the City and County efforts to protect watersheds that are located in both jurisdictions. The agreement calls for establishing common goals for managing the natural resources of shared watersheds; improved coordination of resource management strategies and restoration programs; joint meetings with citizen-based watershed associations and annual "state of our watersheds" reports. One of the first projects that resulted from this historical agreement was the Gwynns Falls Water Quality Management Plan. The Gwynns Falls watershed begins in western Baltimore County and drains into Baltimore City. The headwaters are located in rural/suburban Glyndon, Maryland and the stream drains to the tidal area of the Middle Branch of the Patapsco River in downtown Baltimore. The Patapsco Middle Branch is in the western part of the Baltimore Harbor and ultimately drains into the Chesapeake Bay. Approximately two thirds of the watershed lies within Baltimore County and one third lies within Baltimore City. The Water Quality Management Plan was used for partial fulfillment of the federally mandated National Pollutant Discharge Elimination System Permit (NPDES) and to provide a watershed restoration framework for both jurisdictions. The Parsons Brinckerhoff team has prepared the plan and its goals include: (1) Identify and evaluate non-point source stormwater pollution of the 171 square kilometers (66 square miles) watershed and assess over 214 kilometers (133 miles) of stream, (2) determine management and restoration measures for the reduction of non-point source pollution and reestablishment of stream stability, and (3) provide a watershed restoration framework and planning tool for capital project for both jurisdictions. Plan components include: Watershed characterization, stream assessment, GIS database, forest assessment, stormwater management facility and outfall assessment, SWMM modeling and watershed evaluation and project recommendations.

Parsons Brinckerhoff (PB) lead a team of water resource engineers and environmental scientists to develop a comprehensive water quality management plan for the Gwynns Falls Watershed. The headwaters of the 171 square kilometer (66 square mile) Gwynns Falls watershed begin in Baltimore County and drains through Baltimore City, into the Middle Branch of the Patapsco River and ultimately into the Chesapeake Bay. This project was a joint effort between Baltimore County Department of Environmental Protection and Resource Management (DEPRM) and Baltimore City Department of Public Works (DPW) as a first inter-jurisdictional, regional cooperative restoration effort and initiative. The goals of the water quality management plan were: Identify and evaluate non-point source stormwater pollution and stream degradation; Determine management measures for the reduction of nonpoint source pollution and reestablishment of stream stability; and Provide a watershed restoration framework for Baltimore City and Baltimore County. One of the major plan components was the stream assessment. Field crews walked, collected data and photographed over 214 kilometers (133 miles) of stream within the Gwynns Falls. The streams were divided into approximately 900 individual reaches averaging 227 meters (750 linear feet) each. The large number of reaches and data to be collected presented a unique challenge for the assessment team. Other key assessment features include GIS data management; water quality modeling using EPA SWMM; stormwater assessment that included 48 stormwater management facilities and 82 storm drain outfalls; and a forest patch assessment. The results of the field assessments were used to develop cost estimates and rankings for more than 120 projects within the watershed. Each project was ranked based on cost, water quality and habitat benefit, land availability, public acceptance and educational opportunities. The final product is a list of management recommendations and a prioritized list of restoration projects for incorporation into the City and County's capital improvement programs.

In 1984, the U.S. Army entered into a long-term partnership with the Environmental Protection Agency's (EPA) Chesapeake Bay Program (CBP) with the intent to protect the Bay and its resources for future generations. Over the years, this partnership has blossomedwith the Army taking an increasingly proactive role in protecting, restoring, and promoting stewardship of the Bay watershed. The Chesapeake Bay watershed spans six states and the District of Columbia and encompasses more than 165,760 square kilometers. Within this area, the Army owns 19 installations covering approximately 87,075 hectares (USAEC 2004). The Army's land within the watershed varies in location (from Bay-front to mountaintop), size, and proximity to urban centers. These varied landholdings present unique watershed issues that demand innovative solutions on the part of the Army. Led by the U.S. Army Environmental Center (USAEC), the Army's Chesapeake Bay Program (Army CBP) has supported the Bay-area installations with planning, partnering, public outreach, and resource conservation and enhancement. Specific activities have included submerged aquatic vegetation (SAV) research and restoration, conservation landscaping and low-impact development (LID) training and design, nutrient management planning, watershed planning, and public outreach. Additionally, using a bimonthly newsletter, a Web site, and annual meetings as tools, the Army CBP keeps installation staff abreast of new developments and issues in watershed management and encourages the exchange of information among the widespread installations and with their various federal and state partners. The Army CBP provides an excellent example of watershed-based planning and management over a large scale and with a variety of public and environmental issues. This paper will highlight the various programs and activities that the Army is undertaking in support of theEPA CBP and discuss the challenges and issues of managing multiple parcels of land throughout a large watershed.

American Forests, the nation's oldest citizen conservation organization established in 1875, embarked on a project to analyze the value of urban forest ecosystems in 1990. By 1995 the staff at American Forests had developed a technique for measuring the structure of the land and was searching for the best available scientific and engineering models for calculating the effect of the structure of the land on the functions of air, water, and energy. In 1995 American Forests asked the national hydraulic engineer at the Natural Resource Conservation Service (NRCS) to help American Forest find a solution to a stormwater problem facing communities. He was willing to help, and several months later the TR-55 stormwater model was adapted to a Geographic Information System software application developed by American Forests called CITYgreen. Since that first application, the application to the CITYgreen model has been improved 6 times and the latest version is called CITYgreen for ArcGIS.

Geographic Information Systems (GIS) provides a framework for analyzing the spatial relationships that exist in urban areas among trees, other natural resources, and the built environment. Using GIS, cities now have the tools to map, measure, and quantify the benefits of their urban forests. Collecting, storing, and using data in a GIS about the gray infrastructure, like buildings, roads, and sewer networks, is common in most local governments today. However, spatial information regarding green infrastructure such as, trees, and other vegetation, and their environmental and economic benefits has been absent. Local governments can use this data to make better informed land development and management decisions. The incorporation of high-resolution multispectral satellite and digital aerial imagery enables communities to build a "green data layer,"—a highly accurate representation of their green infrastructure. This data layer can be used in GIS to influence planning, design, and preservation decisions. Using a green data layer, cities can measure their tree cover and set attainable canopy goals so as to put this resource to best ecological use for improving air and water quality. CITYgreen is a GIS software package developed by American Forests as an extension to ESRI's ArcGIS that calculates the services provided to a community by its green infrastructure. The purpose of this paper is to explain the creation of a green data layer and its use in CITYgreen to quantify the benefits of the urban forest.

The American Forest CITYgreen software can be used to evaluate the impact of land use changes in urban area on the environment. The environmental changes include water quality and quantity. This paper explains how the methodology was incorporated into the CITYgreen software.

The emerging cyberinfrastructure-based decision-support systems for aquatic environments assume coupling of real-time monitoring instruments with data-driven models covering spatial and temporal scales from microhabitat to watershed levels. The paper describes a Mobile Large-Scale Particle Image Velocimetry (MLSPIV) mobile unit that allows visualization and quantitative measurements of instantaneous and averaged flow characteristics in rivers over large areas. The unmatched spatial resolution along with the remote, real-time, and fully digital nature of LSPIV makes it an ideal cybertool either as a stand-alone instrument, as presented in the paper, or integrated in large-scale networks. Preliminary tests with similar LSPIV configurations proved that the technique is reliable, flexible, and efficient for monitoring, design, hazard warning, and decision-making in riverine ecosystems.

Eco-Cybernet combines various spatial-temporal information sources and numerical simulators with management decisions. The focus here is the development of a field-based monitoring tool capable of measuring soil origin for assimilation within Eco-Cybernet. The tool, referred to as fingerprinting, uses carbon and nitrogen isotopes and C/N as tracers that fraction in-stream eroded-soils into their land-use/land-management sources. Here, 245 soil data are presented for the tracers from agriculture and forest land-uses in the Upper Palouse, and differences within the bio-chemical cycles are discerned. Among the agriculture vs. forest land-uses, the nitrogen isotope is primarily dependent upon harvesting practice, the C/N is dependent upon litter inputs, and the carbon isotope shows little difference due to the monoculture C3 environment. The tracers are utilized within the fingerprinting tool, and a Bayesian unmixing model is used to measure source contribution to the eroded-soil. Uncertainty is accounted and attributed to a number of potential processes.

The topic of `dam removal' has garnered national attention and been the focus of special sessions at numerous national scientific meetings; yet there remains a disparity between the need to understand and predict the effects of removing dams and the current state of the science. It has thus been argued that the removal of small dams should really be viewed as research opportunities. But why? And more importantly, how? While much has been written on dam removal, the majority of scientific literature published to date is based on anecdotal evidence and/or focused on broad contextual issues surrounding large dams. According to the 2002 Heinz Center report on Dam Removal; however, the vast majority of dams in this country, and almost all dams removed thus far, are small. Given the subtlety of their effects and the wide range of geomorphic contexts in which small dams are found, a consistent set of monitoring protocols are required if we are to develop a comprehensive understanding of dam removal effects. In this way, an empirical set of case lore can be built with which to test more rigorous dam removal models. Using insights gained from the removal of two small dam removals in Oregon; we offer the beginning of a national small dam removal monitoring protocol.

Sediment trapped behind a dam may be chemically contaminated, with the potential to cause toxicity and contaminant bioaccumulation in biota and also to gready complicate dam removal. However, sediment quality has been assessed in only a small fraction of the more than 80,000 reservoirs in the U.S. Therefore, efficient screening and assessment techniques are essential to determine the level of sediment management necessary for dam removals and to avoid unnecessary impacts to the river system. The Massachusetts Riverways Program is working with the USGS to develop the Regional Impounded Sediment Quality Assessment (RISQA), a GIS-based model that assesses the likelihood of contamination in impoundment sediment. The model combines land-level data, such as historic land use and known contamination sites, with the drainage network in the watershed upstream of an impoundment. Reservoirs identified by landscape-level screening as likely to contain contaminated sediment should be individually assessed using a sampling design appropriate for the local situation, a set of sediment quality criteria against which to judge the magnitude of the problem, and a decision framework for selecting the appropriate management action. Survey design and sampling techniques are well established, and range from a quick, qualitative reconnaissance survey to a statistically-rigorous coring survey. Sediment quality criteria vary from state to state, and are typically either narrative standards or are based on biological/toxicological assessments and/or bulk sediment chemistry. In addition to sediment quality criteria assessments, the proposed sediment management decision framework considers sediment transport capacity of the stream, downstream sensitivity to sedimentation, and contaminant bioavailability. Available management options include natural erosion and deposition downstream, staged dam removal, full or partial dredging, isolation/stabilization, or a combination. Choosing among the management options requires consideration of site-specific social concerns and financial limitations as well as technical issues. This paper outlines a process for sediment assessment as well as a potential management framework when dealing with sediment on a dam removal project.

In this paper we synthesize a series of small dam removal studies to examine how changes in channel form can affect riparian vegetation, fish, macroinvertebrates, mussels, and nutrient dynamics. Our results suggest that ecosystems may follow two trajectories of recovery following dam removal. First, ecosystems may fully recover to pre-dam conditions, although this may be unlikely in many cases Even if full recovery occurs, the timescales over which different attributes recover will vary greatly and may be perceived by the public or management agencies as not recovering at all. Second, ecosystems may only partially recover to pre-dam conditions as the legacy of environmental damage of long-term dam presence may not be reversible or because other watershed changes inhibit full recovery. The potential for full or partial recovery is likely driven by the sensitivity of particular organisms, the characteristics of the dam removed, and the local geomorphic conditions of the watershed. Scientists and management agencies should assess the potential for full or partial recovery prior to dam removal and, in particular, should identify those species or groups of species that are likely to not recover to pre-dam conditions.

When dams are removed, the impacts from the erosion and transport of reservoir sediment are often the primary concern. Predicting the sediment impacts is critical to ensure that the dam is removed in a safe, controlled manner and the downstream mitigation or protective measures can be appropriately designed. However, because of the limited data and inadequate models, the quantification of sediment impacts is subject to great uncertainty. A diffusive wave model of downstream aggradation is presented that may simplify the analysis of deposition of coarse material downstream. The diffusive wave model is tested against two sets of laboratory data and a one-dimensional sediment transport model (GSTAR-1D).

The U. S. Department of Interior, Bureau of Reclamation is involved in many dam decommissioning projects in the Western United States. These projects involve complete to partial dam removal. Reclamation has analyzed the sediment impacts of several dam decommissioning projects: Battle Creek Dams in California, Matilija Dam in California, and Savage Rapids Dam in Oregon. The dams range from small to large and the impacts also span a large range. The major components of these projects and specific lessons learned are summarized.

Dam removal projects are becoming increasingly common, yet the accuracy of quantitative sediment predictions remains uncertain. This situation results because of a general lack of scientific monitoring during dam removals, and the fact that the majority of dams that have been removed are small in size. Resource managers dealing with dam removal projects rely heavily on results from predictive numerical modeling to assess environmental impacts on the human environment. If the models are not properly applied, predicted impacts can be erroneous. This paper provides some guidance for the application of numerical sediment transport models to improve their accuracy and utility for dam removal investigations.

Not all dam removals will need detailed sedimentation studies. However, in many cases it is not possible to predict how significant those processes might be without a detailed sediment investigation. The author knows of no computer program that qualifies as an "expert system" for making such predictions. However, by coupling the computational capability of HEC-6T with principles of river morphology and sedimentation engineering, he has made computations for a variety conditions including such highly disturbed watersheds as Mt. Saint Helens. Likewise, one who understands river mechanics, sedimentation engineering and geomorphology can discover much about the sedimentation processes that will result from the removal of a dam. However, one has to formulate, very carefully, what questions to ask of the computer program and to design the necessary computational experiments to address those questions. Knowledge gained from each application has contributed features for HEC-6T that aid in modeling dam removals.

Prediction of sediment transport dynamics following dam removal usually requires extensive field data, the collection of which requires both resources and time. Certain management decisions regarding dam removal, however, may be required before resources may be allocated to provide sufficient data to evaluate whether dam removal is a viable option. Here, we present a case study and demonstrate that some aspects of the sediment transport characteristics following dam removal can be evaluated with very limited information. The case study in question involves J.C. Boyle, Copco, and Iron Gate Dams on the Klamath River, California which together have an estimated 12 million m³ of sediment deposited in their reservoirs. With a reconnaissance field observation and upon examination of the very limited existing field data, we determined that it is possible to evaluate the potential for sediment deposition downstream of the dam following the removal of the dams under the worst-case-scenario assumptions. The evaluation was carried out with the help of DREAM-1, one of the Dam Removal Express Assessment Models developed at Stillwater Sciences. Results of the assessment indicate that potential sediment deposition would occur only for a brief period within approximately 10 km downstream of the dam with a maximum thickness of sediment deposition no more than 1.2 m.

A generalized model of channel evolution upstream of dam removal sites has been developed based upon observations of dam removal projects, dam failures, reservoir drawdowns, at post glacial lakes and dams, along with available records and literature. The complimentary flow chart identifies a series of potential channel evolution trends and provides examples of each. The model can be used as a preliminary screening tool to assess potentialdam removal impacts. Several parameters are used to help identify potential channel trends include the presence of sediment, presence or absence of a well defined thalweg across the pool bed, type of sediment deposit, and sediment gradation. The final parameter is the ratio between the pool's width versus the anticipated pre-dam channel width, acknowledging that narrow pools behave differently from wide pools.

As many dams in the United States approach or exceed their design lives, dam removal studies have become increasingly important. Particularly, the management of the sediment that has accumulated behind dams is a challenging aspect of dam removal. HEC-6, a one-dimensional sediment transport computer model is shown to be a suitable model for predicting sediment effects due to dam removal, especially when the focus is on quantities of material scoured, downstream zones of aggradation, and temporal changes to sediment concentrations. Although HEC-6 was not originally developed to study dam removals, there are features available within the model that can be adapted to simulate the dam removal process. Methods for approaching sediment transport modeling for dam removal are discussed herein.

The Condit Dam is one of several large dams in the western U.S. currently being considered for removal. Other removal projects have become costly due to water quality mitigation associated with trapped sediment removal. The proposed technique for removing Condit Dam involves rapidly evacuating the reservoir, eroding sediment, and removing the dam. Estimated project costs are less than $20 million.

Dams have had a global impact on natural water resources. Approximately 800,000 dams have been constructed worldwide. On a global scale, river damming has increased the residence time of river waters from 16 days to 47 days. Dams have increased standing water more than 700 percent. There are more than 75,000 major dams in the United States, most of which are relatively old and 90 percent of which are privately owned. A "major" dam is one taller than 7.6 m or impounding more than 61,650 m³. These dams have a design life expectancy that can be extended by regular maintenance. However, many times this is not done. The Federal Emergency Management Agency (FEMA) found that about 9200 dams in the U.S. are classified as high hazard due to inadequate maintenance, lack of spillways, and lack of sediment management. About 35 percent of these dams have not had safety inspections in over a decade. Repairing older dams is often more expensive than removing them, making removal an attractive alternative. Disregarding maintenance problems, many proposed removals are based entirely on the environmental impacts of dams. The National Research Council has deemed research for the rehabilitation and restoration of aquatic ecosystems a priority for rivers in the United States. While dams have provided valuable services such as irrigation, hydroelectric power, navigation, flood protection, and recreational opportunities, they have had a dramatic impact on rivers and streams. Flow regimes, channel morphology, sediment transport, and various ecological parameters such as the quality of riparian and aquatic habitats have all been influenced by dams. Dams have also increased soil salinity, and flooding, impeded or eliminated fisheries, and produced unnatural nutrient loading. Although as many as 450 smaller dams have already been removed in the United States, few detailed studies of existing dams or dam removal have been conducted and therefore a paucity of data exists for predicting the geomorphic effects of dam removal. Due to the complex nature and prolonged duration decision framework considers sediment transport capacity of the stream, downstream sensitivity to sedimentation, and contaminant bioavailability. Available management options include natural erosion and deposition downstream, staged dam removal, full or partial dredging, isolation/stabilization, or a combination. Choosing among the management options requires consideration of site-specific social concerns and financial limitations as well as technical issues. This paper outlines a process for sediment assessment as well as a potential management framework when dealing with sediment on a dam removal project.

The state of Michigan is interested in removing two low-head dams in an 8.8 km reach of the Kalamazoo River between Plainwell and Otsego, Michigan while minimizing impacts to the study reach and downstream reaches. The study was designed to evaluate the erosion, transport, and deposition of sediments over a 17.7-year period using the channel evolution model CONCEPTS for three simulation scenarios: Dams In, Dams Out, and Design. The total mass of sediment emanating from the channel boundary, for the Dams In case, shows net erosion of 3,350 T/y for the study reach, with net transport (suspended and bed load) of 5,010 T/y passing the downstream boundary. For the Dams Out case, net erosion jumps to 41,600 T/y with net transport of 59,200 T/y passing the downstream boundary. For the Design case, net erosion was 3,870 T/y with transport of 20,100 T/y passing the downstream boundary. The most significant findings were: (1) removal of the low-head dams will cause erosion in the study reach and increased sediment loads passing the downstream boundary, (2) bed erosion is the major source of eroded sediment, and (3) the Plainwell reach is the greatest contributor of total sediment and fine-grained sediment.

The processes controlling fine sediment deposition, storage, and transport within laterally constricted pools of the North Fork Cache la Poudre River, northern CO, were investigated following the 1996 release of approximately 7,000 m³ of sediment. The release provided an opportunity to develop a field data set of fine sediment dynamics and to test the predictions of three different one- and two-dimensional sediment transport and hydraulic models against the field observations. Sediment transport within the North Fork following the release is similar, on a smaller scale, to transport of sediment following dam removal. Sediment from the release filled pools up to 3.5 m deep, and defined the starting condition for the modeling. During an experimental release of water from the reservoir in March 1997, sediment was scoured from the thalweg of pools and transported by a combination of translation and dispersion. Some sediment became deposited as higher lateral channel bars following thalweg scouring as sediment moved from pool to pool downstream during subsequent flow releases. At high discharges, the development of a strong shear zone prevented degradation of sediment deposits within the eddy. One-dimensional HEC-6 results provided the greatest agreement between predicted and measured pool bed elevation change. Results from the two-dimensional model RMA2 substantially improved the representation of eddy pool hydraulics, and provided input for bed load and total load computations which accurately delineated areas of scour and deposition. Less energetic fluvial systems could result in longer-term deposition of sediment than was experienced on the North Fork.

A plan has been made to remove Matilija Dam on the Ventura River. With dam removal, the delta in the reservoir and the downstream channel are expected to undergo major changes in morphology. The FLUVIAL-12 model was employed to simulate reservoir and river channel responses after the dam removal. As the first step, the model was calibrated using the Ventura River data to establish its validity. In calibration, the model was used to simulate the fluvial processes starting from the time of dam completion. The simulated sediment deposition above Matilija Dam matches closely with the measured deposits by the U. S. Bureau of Reclamation. A large amount of sediment has been stored in the reservoir; some of the stored sediment will be transported downstream after the dam removal. An important consequence of dam removal is the major increase of sediment release to the river channel downstream. The sediment supply to the downstream reach is not only from the stored sediment in the reservoir but also from natural sediment inflow from the upstream watershed. Therefore, sediment supply to the downstream reach will exceed the natural sediment flow before the dam presence. This situation tends to overload the downstream reach with sediment to result in excessive deposition. The amount of sediment release from the area above the removed dam is closely related to the changes in reservoir morphology. It is necessary to model changes in channel bed profile and in channel width during erosion in order to determine the amount of sediment removal. The amount of sediment release may not be simulated using an erodible-bed model but it may be determined using an erodible boundary model.

Dam removal is being used to experimentally investigate hydrologic, geomorphic and ecological links in streams, particularly riparian vegetation and floodplain wetlands as mediated by channel adjustment. Damming leads to accumulation of organic matter and nutrient-rich sediments and altered hydrology and geomorphology. Following dam removal, altered hydraulics will drive upstream channel evolution which will determine the spatial relationship between the channel and the floodplain. Channel wetted perimeter will decrease exposing nutrient-rich sediments for floodplain ecosystem succession. In this paper preliminary results are shown from an experimental dam removal. Due to the progress of the dam removal particular emphasis will be focused on the fate of interstitial nutrients within the developing floodplain and floodplain plant community succession. Initial data show floodplain wetland interstitial water N and P concentrations 10–20X greater than adjacent surface water which initially will likely compromise floodplain nutrient retentive capacity. Here, floodplain nutrient retentive capacity is defined as the system's ability to attenuate surface water nutrient concentrations during flood events. Secondary succession is primarily measured using biomass of macrophytes (AFDM) and benthic algae (chl a), and within the rooting-zone using fungal biomass and bacterial productivity. Field nutrient data from the floodplain wetland are being collected throughout the successional process (surface water, interstitial and sediment surface). In addition to the field studies, development of floodplain retentive capacity is being simulated via floodplain wetland mesocosms within a greenhouse under variable hydrologic conditions in the presence and absence of wetland floodplain vegetation. These contrasting experimental techniques will elucidate fundamental links between geomorphology, hydrology, and ecosystem processes in streams, as well as provide novel data on environmental response following dam removal.

The California Department of Water Resources, Division of Safety of Dams (DWR-DSD), has determined that San Clemente Dam on the Carmel River in Monterey County, California, does not meet seismic safety standards. Several alternatives are being considered to bring the dam to a safe condition. These alternatives include thickening of the approximately 22-m-high, concrete arch dam, lowering of the dam to the extent necessary to meet seismic standards, and complete removal. At the present time, the reservoir upstream from the dam, which had an original storage capacity of about 1.76M m³, is nearly filled with sediment. An additional alternative has recently been suggested that would divert the Carmel River into San Clemente Creek near the head of the reservoir in a manner that would isolate about 80 percent of the sediment that is stored in the reservoir. The 31-km reach of the Carmel River downstream from the dam passes through urbanized areas within the Carmel Valley; thus, flooding and channel stability are matters of significant concern. In addition, the Carmel River contains habitat for the endangered steelhead and red-legged frog that could potentially be affected in both positive and negative ways by removal or lowering of the dam. Sediment-routing studies were conducted using the HEC-6T model to evaluate the response of the river to elevated sediment loads associated with the various removal/retrofit alternatives. The results are being used by the owners of the dam and the resource agencies to evaluate potential public safety impacts due to increased flooding and channel instability, as well as the potential for habitat restoration as the river recovers from the increased sediment loading. The modeling was performed in an interactive manner that allowed for management of complexities associated with the size-range and spatial distribution of the reservoir deposits and changes in the dam configuration. Results obtained from the modeling studies are believed to realistically describe the magnitude, and temporal and spatial distribution of erosion within the reservoir, and deposition and subsequent erosion in the river as the elevated sediment loads pass downstream.

The Goldsborough Creek Dam Removal and Stream Restoration Project is located in Mason County, Washington and was authorized under Section 206 of the Corps' Continuing Authorities Program. The project, which was initiated by Seattle District Corps of Engineers in cooperation with local sponsors, removed a deteriorated dam structure that was a hindrance to fish passage along Goldsborough Creek. Upstream of the project, the creek flows freely through forested areas and includes 14 river miles draining 51 square miles of high-quality habitat. The restoration objective was to remove the dam and allow for unhindered upstream and downstream passage of resident and migratory fish. A project was formulated that resulted in a highly structural approach to post-dam removal channel stabilization but resulted in a high level of certainty in limiting potential undesirable channel response and adverse sediment related impacts. The trade-off associated with the level of restoration of the area disturbed by the footprint of the Goldsborough Creek Dam and pool versus the avoidance of potential adverse impacts on stream stability and sediment transport processes are discussed. This trade-off is evaluated in the context of large-scale watershed benefits of restoring connectivity through the former project site.

Increased production of ecosystem services (e.g., sediment and nutrient load reduction, flood peak reduction, wildlife habitat, and biodiversity) is likely to be achieved through strategic management of agricultural landscapes. This paper explores the role of landscapes in improving ecosystem service generation on a watershed scale. Four ecosystem service related objectives are considered; they involve reduction of flood peaks and sediment, nitrogen and phosphorus loads. The authors have developed a model to identify land uses and management practices that most cost-effectively generate these ecosystem services. Cost effectiveness is integrated by considering resulting impacts to landowner income, interpreted as a fifth objective. The spatial decision support model used to solve the underlying watershed management problem couples the U.S. Department of Agriculture's Soil and Water Assessment Tool (SWAT) and a fairly new, multi-objective evolutionary algorithm known as SPEA2. Application of the model to the Big Creek watershed, a complex basin located in southern Illinois, demonstrates that it allows the assessment of tradeoffs between competing objectives, namely agriculturalcommdity production and generation of ecosystem services. Moreover, it confirms that this integrative modeling approach could enable stakeholders and policy makers in identifying a suitable set of land use and management practices at a watershed scale.

The GIS Weasel is a map and Graphical User Interface (GUI) driven tool that has been developed as an aid to modelers in the delineation, characterization of geographic features, and their parameterization for use in distributed or lumped parameter physical process models. The interface does not require user expertise in geographic information systems (GIS). The user does need knowledge of how the model will use the output from the GIS Weasel. The GIS Weasel uses Workstation ArcInfo and its the Grid extension. The GIS Weasel will run on all platforms that Workstation ArcInfo runs (i.e. numerous flavors of Unix and Microsoft Windows).The GIS Weasel requires an input ArcInfo grid of some topographical description of the Area of Interest (AOI). This is normally a digital elevation model, but can be the surface of a ground water table or any other data that flow direction can be resolved from. The user may define the AOI as a custom drainage area based on an interactively specified watershed outlet point, or use a previously created map. The user is then able to use any combination of the GIS Weasel's tool set to create one or more maps for depicting different kinds of geographic features. Once the spatial feature maps have been prepared, then the GIS Weasel s many parameterization routines can be used to create descriptions of each element in each of the user s created maps. Over 200 parameterization routines currently exist, generating information about shape, area, and topological association with other features of the same or different maps, as well many types of information based on ancillary data layers such as soil and vegetation properties. These tools easily integrate other similarly formatted data sets.

Hydrologic models are heavily used in the Truckee River Basin to support water operations. A suite of models constructed using the RiverWare modeling framework is used to support basin-wide decisions on water operations. The models are used for forecasting as well as near-real time water accounting to assist in the application of basin policy. Additionally, the models are being configured to assist in day to-day release scheduling in the future, as well as long-term basin planning. Three models are used in a variety of ways to meet the decision support needs of the basin stakeholders. The models include a near-real time water accounting model, a hydrologic forecasting model, and an operations/planning model. The ability to interconnect the models with each other, as well as other models, provides decision makers in the basin with a versatile set of tools to improve basin water operations.

Droughts present a unique challenge to water managers throughout the world and the current drought in the western United States is taxing facilities to the limit. Coping with this severe drought requires state of the art decision support systems including efficient and accurate hydrologic process models, detailed hydrologic data bases and effective river systems management modeling frameworks. This paper will outline a system of models developed by the Bureau of Reclamation, the US Geological Survey, the University of Colorado and a number of other governmental and university partners. The application of the technology to drought management in several key western river basins will be discussed.

The Curve Number (CN) method is routinely used to estimate runoff and peakflows following forest fires, but there has been essentially no literature on the estimated value and temporal variation of CNs following wildland fires. In May 2000, the Cerro Grande Fire burned the headwaters of the major watersheds that cross Los Alamos National Laboratory, and a stream gauging network presented an opportunity to assess CNs following the fire. Analysis of rainfall-runoff events indicated that the pre-fire watershed response was complacent or limited watershed area contributed to runoff. The post-fire response indicated that the complacent behavior continued so the watershed response was not dramatically changed. Peakflows did increase by 2 orders of magnitude following the fire, and this was hypothesized to be a function of increase in runoff volume and changes in watershed network allowing more efficient delivery of runoff. More observations and analyses following fires are needed to support definition of CNs for post-fire response and mitigation efforts.

The Cerro Grande fire of April 2000 burned 19,300 hectares (ha) (47,650 acres [ac]) in and around the Los Alamos National Laboratory (LANL). Wright Water Engineers, Inc. (WWE) analyzed immediate post-fire flood hydrology because greatly increased flood and debris flows in the many burned subbasins posed concerns to downstream areas and infrastructure of LANL. After three years of forest recovery and working with scientists and land managers of LANL, WWE conducted evaluations on the effect of the then-ongoing revegetation/restoration of the burned areas on flood flows, specifically for the 100-year flood (Q₁₀₀). Applying the SCS Technical Release 55 (TR-55) method, WWE computed pre-fire and post-fire runoff curve numbers (CNs) for 31 subbasins. These data, supplemented by similar data for 24 small subbasins affected by the 2002 Long Mesa fire at Mesa Verde National Park, were used in an analysis that included four major components: (1) Estimation of CNs that represent pre-fire conditions for watersheds; (2) use of CN ratios to demonstrate subbasin recovery, including burn severity effects represented by a Wildfire Hydrologic Impact (WHI) factor; (3) for various WHIs, development of a theoretical relation showing the change in the CN ratio due to post-fire hydrologic changes during an "ideal" recovery period; (4) from these concepts estimate the Q₁₀₀ at various stages of subbasin recovery. For most subbasins with moderate to severe burn intensities, recovery was estimated to take from 6 to 10 years. For the most severely burned subbasins, however, analysis shows that recovery to pre-fire hydrologic conditions may take up to 10 to 20 years.

The hydrological impact of a severe burn forest fire, when viewed from the vantage point of on-the-ground research hydrologists, is remarkable. While basin-wide impacts are measured in terms of increased curve numbers, increased flooding potential, vegetation and wildlife damage, and generalized potential soil loss via erosion, one can better understand post-fire changes when one also sees and measures detailed hydrological changes on a micro scale. It is then that the truly disastrous nature of a major forest fire hits home. The 2000 Bircher Fire in the heart of the Mesa Verde National Park (MVNP) provided the opportunity for the Wright Paleohydrological Institute (WPI) to document detailed forest hydrology, riparian zone, and channel regime changes and to watch them happen. The opportunity was available because of our ongoing hydrological research in Mesa Verde for the five years preceding the fire, coupled with four years of study after the fire while performing paleohydrology studies under National Park Service (NPS) permits. The story that we saw unfold is not a pretty one in terms of both natural resource damage and loss of cultural archaeological artifacts.

The increase in severe wildfires in recent years is due in part to an abundance of fuels in forests. In an effort to protect values at risk, and decrease the severity of wildfires, forest managers have embarked on a major program of fuel reduction. Past research has shown that such fuel reduction may have minimal impact at a hillslope scale, but when numerous hillsides are disturbed within a watershed over a number of years, the cumulative effect of such disturbances may be unacceptable. In addition, road networks are necessary to support fuel management activities by providing access for thinning crews, small diameter timber extraction, and fire crews. These road networks were frequently designed and constructed to minimize cost, and do not necessarily minimize adverse watershed impacts. Research findings from wildfire, fuel management, and roads will be presented to provide a context for predictive modeling. There are some new predictive tools to aid in watershed analysis. These include the GeoWEPP GIS wizard, the online WEPP:Road Batch processor and WEPP FuMe fuel management analysis tools, and a revised WEPP hillslope model with improved water balance and lateral flow capabilities. In this paper, we use these new technologies to explore the sources of sediment and runoff within a typical forested watershed. The paper shows improvements in runoff prediction with the revised WEPP model, as well as the relative importance of roads, wildfire, prescribed fire, and thinning operations in generating sediment at the hillslope and watershed scales. The analysis of the performance of the modified WEPP interface showed that there are problems within the WEPP Watershed stream flow routing routines that will need to be addressed before use of this modified model can be recommended.

Rapid post-fire watershed assessment to identify potential trouble spots for erosion and flooding can potentially aid land managers and Burned Area Emergency Rehabilitation (BAER) teams in deploying mitigation and rehabilitation resources. These decisions are inherently complex and spatial in nature and require a distributed hydrological modeling approach. The extensive data requirements and the task of building input parameter files have presented obstacles to the timely and effective use of complex distributed rainfall-runoff and erosion models by BAER teams and resource managers. Geospatial tools and readily-available digital sources of pre-fire land cover, topography, and soils combined with rainfall-runoff and erosion models can expedite assessments if properly combined, provided a post-fire burn-severity map is available. The AGWA (Automated Geospatial Watershed Assessment) hydrologic modeling tool was developed to utilize nationally available spatial data sets and both empirical (SWAT) and more process-based (KINEROS2) distributed hydrologic models (see: www.tucson.ars.ag.gov/agwa). Through an intuitive interface the user selects an outlet from which AGWA delineates and discretizes the watershed using a Digital Elevation Model (DEM). The watershed model elements are then intersected with soils and land cover data layers to derive the requisite model input parameters. The chosen model is then run, and the results are imported back into AGWA for graphical display. AGWA can difference results from pre- and post-fire model simulations and display the change on the modeled watershed. This allows managers to identify potential problem areas where mitigation activities can be focused. An overview of AGWA and an application of it to the 2003 Aspen fire north of Tucson, Arizona are discussed herein.

Major concerns after wildfires are the increased erosion and flooding potential due to loss of the protective forest floor layer, loss of water storage, and the creation of water repellent soil conditions. Treatments to mitigate postfire erosion and runoff are commonly applied on highly erodible areas; however the effectiveness of these treatments has had limited scientific evaluation. In recent years postfire hillslope treatment effectiveness has been evaluated by using sediment fences and small catchments to directly measure sediment yields from burned hillslopes and relate those results to the specific rain events that caused them. In addition, the erosion from areas treated with various rehabilitation treatments (seeding, mulching, erosion barriers, etc.) is compared to non-treated areas. Although many of these studies are still in progress, preliminary results suggest that some mitigation treatments may help reduce erosion for some, but not all, rain events. Immediately after installation, contour-felled log erosion barriers can reduce erosion up to 70% for small rain events. For high intensity rain events (10-min max intensity of 40 mm hr^–1 or greater) there little difference in erosion reduction between treated and non-treated areas. Other studies suggest that the natural mulch provided by dead conifer needles in areas of low and moderate burn severity can reduce rill erosion by 30 to 40% and interrill erosion by 50 to 70%.

The Missionary Ridge wildfire of 2002 burned more than 28,000 hectares (ha) (70,000 acres [ac]) near Durango, Colorado. Risks posed by increased runoff and sediment and debris flow potential were widely recognized, prompting implementation of rehabilitation measures in many areas that had burned. This paper describes the successful implementation of rehabilitation measures by the Florida Water Conservancy District (FWCD) with the assistance of Wright Water Engineers, Inc. (WWE) in the Knight Canyon and South Drainage watersheds. The watershed is located above the spillway of the Lemon Reservoir, consisting of 184 ha (454 ac), over half severely burned in the wildfire. FWCD officials were concerned with the protection of the reservoir spillway from debris flows and the potential for heavy sediment loading to the Florida River and downstream water supply intakes. FWCD, with assistance from WWE, obtained a Section 319 grant through the Colorado Department of Public Health and Environment (CDPHE) for implementation of rehabilitation measures. Rehabilitation measures implemented in the Knight Canyon and South Drainage watersheds included log erosion barriers (LEBs) over 93 ha (230 ac), at a density of 220 to 615 per ha (90 to 250 per ac) and 13 check dams and detention basins. These measures have been regularly maintained and repaired since they were installed. Five debris racks ranging in width from 5 to 14 meters (m) (15 to 47 feet [ft]) were installed along major drainage paths, and as of October 2003, had trapped nearly 150 cubic meters (m³) (200 cubic yards [yd³]) of debris. Other practices, including hand seeding of approximately 41 ha (100 ac) and mulching and hand crimping of 30 ha (75 ac) have proven effective. The effectiveness of the rehabilitation measures was truly put to the test when 6.27 centimeters (cm) (2.47 inches [in]) of rain fell over a 13-hour period on September 9, 2003. Runoff, sediment, and debris from the Knight Canyon watershed during this event were substantially less than from other comparably sized, nearby watersheds that had not received such extensive treatment. This paper also provides an overview of the effects of the Missionary Ridge wildfire of 2002 on the Knight Canyon and South Drainage, a roughly 184-ha (454-ac) watershed adjacent to the spillway of the Florida Water Conservancy District's (FWCD's) Lemon Reservoir near Durango, Colorado. The paper describes: 1) the post-fire hydrologic assessment and analyses performed by WWE in conjunction with FWCD, 2) rehabilitation efforts by FWCD including measures implemented and sources of funding, 3) effectiveness of rehabilitation measures during rainfall events since the 2002 wildfire, and 4) "lessons learned" for future rehabilitation efforts.

We describe contaminant transport modeling activities for reaches of Pueblo Canyon, near Los Alamos National Laboratory (LANL), state of New Mexico, USA, during the summer rainy season of 2002; 2 years after the Cerro Grande fire. The REACH6 model is a distributed, dynamic model which uses sediment discharge and stream channel characterization data to compute transport of sediment-associated contaminants, i.e. heavy metals such as plutonium-239, 240 (Pu-239, 240 or sometimes simply Pu). We integrated the application of the US Army Corps of Engineers models for hydrology, hydraulics, and sediment transport with the REACH6 model. We compared data from suspended sediment and contaminant concentration measurements in Pueblo Canyon with corresponding calculations from the REACH6 Model. For a flood event on June 22, 2002, the measurements indicated that during the suspended sediment sampling period about 14.4 mCi of Pu was transported out of lower Pueblo Canyon. The REACH6 prediction for the same sampling period was a transport of 23.4 mCi or some 62% more than the value of 14.4 mCi. Given the uncertainties in flow and sediment monitoring and the fact that the model includes bed load transport as well as suspended sediment transport, these prediction results are a good match with the measured values. Even so, data from more events are needed to evaluate better the uncertainty associated with these predictions. The contaminant transport model provides LANL with opportunities to develop state-of-the-art adaptive management and decision support tools for its environmental programs. However, these programs must adapt their network design and operation; reach sampling, and reporting procedures to take advantage of these opportunities. The adaptations must include more frequent documentation of contaminant inventories in the channel systems and additional monitoring of flow, sediment and contaminants.

Erosion and runoff have been observed to increase following fire. Land managers and Burned Area Emergency Rehabilitation (BAER) teams must be able to estimate these post-fire changes. Studies of post-fire erosion on burned watersheds show that the concentrations of sediment eroded from burned rangeland and forested hillslopes in the southwestern United States can be extremely high. Since wildfire primarily impacts soils and vegetation cover on hillslopes, it is appropriate to assume that changes in hillslope conditions will result in changes in runoff peak, volume and sediment yield. The AGWA (Automated Geospatial Watershed Assessment www.tucson.ars.ag.gov/agwa) hydrologic modeling tool employs both an empirical model (SWAT) and a more process-based model (KINEROS2). In order to study how these models should be modified to provide land managers with a means to assess the impact of fire, the models were applied on two burned watersheds. Analysis of data from the Marshall Gulch watershed near Tucson, Arizona, indicates that changes in runoff volume are small compared to changes in peak runoff. The application of the KINEROS2 model to burned conditions at the Starmer Canyon near Los Alamos, New Mexico shows a pattern of change over time that is consistent with watershed recovery. Calibrated hillslope roughness values are consistent with independent estimates for roughness under bare conditions following the fire to roughness consistent with forested conditions three years later. The modeling also indicated that increasing hillslope roughness over time accounts for much of the change in runoff response.

The NRCS Geo-Hydro system will develop input for the Natural Resources Conservation Service (NRCS) WinTR-20 hydrologic model from GIS data. Required GIS layers which need to be developed by the user for import to the interface include elevation, land use, and hydrologic soil group. A stream location layer is optional but recommended. The user may also import any other layers which would be useful in locating a watershed such as political boundaries, roads, etc. These data are available for much of the United States through the NRCS Geospatial Data Gateway and other sources. The WinTR-20 computer program is used to estimate peak discharge and runoff volume from watersheds for use in designing water control structures and in determining impacts of changing land use on the hydrologic system. NRCS Geo-Hydro is based upon the ArcView GIS program from Environmental Systems Research Institute (ESRI). The following software requirements are necessary to operate NRCS Geo-Hydro: ArcView GIS Version 3.2 or 3.3, ArcView Spatial Analyst Extension version 1.1 or greater, NRCS Geo-Hydro ArcView project and databases. Even though the system is point-and-click, basic familiarity with GIS operations and hydrologic analysis is recommended. NRCS Geo-Hydro is organized to automate the process used in a typical watershed hydrologic analysis. Its operation is grouped into a series of menus, buttons, and tools which are designed to be used in a sequential manner. Further refining or use of advanced WinTR-20 options may then be accomplished through the use of the WinTR-20 Controller/Editor. NRCS Geo-Hydro and WinTR-20 systems have comprehensive user guides, training material, example data, and other technical documentation.

The vision for future web-based models and the tremendous potential for an integration of the Internet and environmental modeling has driven this project. The objective is to investigate the feasibility of a web-based hydrologic model as applied to the Lower Rio Grande, Texas. The development of a web-based flow routing model is a fundamental step in that direction. Java programming, U.S. EPA Reach File 1 (RF1) GIS dataset for the Conterminous United States, Internet GIS applications (ArcIMS) and water quality data (Texas Natural Resource Conservation Commission—TNRCC, now the Texas Commission on Environmental Quality — TCEQ) have been used in development efforts. In the course of the work done here, several issues came to light such as the need for Java Servlets, model interaction with ArcIMS, and the need for SQL databases. The results are presented in the form of a current architectural framework and a predicted setup. It was concluded that there is significant potential for web-based modeling in order to minimize the limitations of traditional modeling approaches.

This paper presents a GIS-based program called GISHydro2000. This tool was developed by the author and is used extensively by state government and private consultants in the development of predictions for flood behavior in the state of Maryland. This paper presents a demonstration of the program's overall functionality and underlying spatial database. An actual example watershed will be analyzed to illustrate how GISHydro2000 works and the tools it provides.

A Hydrologic Information and Observing System (HIOS) is being designed and developed by a group of academic hydrologists and the San Diego SuperComputer Center. This is part of a research program supported by the National Science Foundation through the Consortium of Universities for the Advancement of Hydrologic Science, Inc (CUAHSI). HIOS components include a hydrologic observations database, a digital watershed which synthesizes the hydrologic observations with GIS, remote sensing and weather and climate data, and a hydrologic analysis and visualization component to quantify fluxes and flows of water and constituents through the phases of the hydrologic cycle for a watershed region. Digital products from all HIOS components are stored in a Hydrologic Digital Library. The Neuse basin in North Carolina is being used as the illustrative watershed for development of HIOS.

In the last ten years, there has been a growing understanding of the importance of looking at water resource issues from a watershed perspective. Storm water, stream flow, groundwater, and aquatic resources are linked by the hydrologic cycle. Analysis of water resources problems invariably leads to interactions among these elements. Typical goals for watershed management are to reduce flooding, improve water quality, or restore lost habitat. It is not unusual for projects to serve multiple goals, nor is it unusual for the goals to change as stakeholders become more involved. Two methods of determining watershed condition are monitoring and modeling. Monitoring can provide good information on the current state of the watershed. However, when it is necessary to estimate changes resulting from future conditions, or to test alternative improvement scenarios, a watershed model is the primary tool. There are a large number of hydrologic and water quality models which have been developed or adapted for use in analyzing watershed processes. A comprehensive survey of computer models for analyzing water quality was published by the Environmental Protection Agency (EPA) in the Compendium of Tools for Watershed Assessment and TMDL Development, (Shoemaker et al, 1997) which described three levels of models: Simple, Mid-Range, and Detailed. They can be categorized by the amount of input data needed, the degree of effort and expertise needed, the need for calibration, and the accuracy of the results.

Many municipalities are facing increasing development and economic pressures while at the same time trying to maintain an environmental balance in their community. Watershed management master plans can be prepared to assess existing environmental conditions as well as to plan for the future. Anne Arundel County, Maryland has not only chosen to perform this activity through a watershed study, but has also recognized that they need to go one step further to put their plan into action. They have chosen to take the Severn River Watershed Management Plan Study and create an interactive Watershed Management Tool (WMT). This tool will bring together spatial and non-spatial environmental data from the study, and water quality and quantity modeling results into an electronic format easily available to County staff.

In New Jersey and throughout the country, the new Municipal Stormwater Regulation Program will require significant changes in the way stormwater infrastructure is managed. Digital mapping can offer a variety of solutions to make this process easier. A digital map allows the user to manage multiple sheets in a single electronic file, and to retrieve the necessary mapping information in a matter of seconds. By taking digital maps to the next level with Geographic Information System (GIS) technology, it is also possible to add other critical data right to the map itself. Whereas a digital map will allow the user to view the location of a stormwater drainage pipe in relation to its surroundings, GIS technology will allow the user to view tables of information about the same stormwater drainage pipe with a simple click of the mouse. Entire infrastructure systems, as well as Stormwater Management Plans and Stormwater Pollution Prevention Plans can be mapped, and a wide variety of related data can be organized and managed with GIS. The zoning and land use aspects associated with good stormwater management and water quality improvement practices can also be tracked with GIS. For example, by performing a build-out analysis, it is possible to study the impact of future growth and development on a municipality or region. By analyzing the "what-if" factors of additional impervious surfaces, potable water needs, and even pollution from additional automobiles now, it will be possible to utilize Smart Growth and related initiatives to prevent environmental damage before it occurs, rather than trying to deal with its impact later on. GIS can also assist with the public education initiatives needed to make these changes seem both positive and possible.

A distributed grid-based watershed mercury loading model has been developed to characterize the spatial and temporal dynamics of mercury from both point and nonpoint sources. The model simulates flow, sediment transport, and mercury dynamics on a daily time step across a diverse landscape. The model is composed of six major components: (1) an ArcGIS interface for processing spatial input data; (2) a basic hydrologic module; (3) a sediment transport module; (4) a mercury transport and transformation module; (5) a spreadsheet-based model post-processor; and (6) links to other models such as WASP and WhAEM 2000 developed by the U.S. Environmental Protection Agency (EPA). The model fully uses the grid processing capacity of the latest ArcGIS technology. The water balance, sediment generation and transport, and mercury dynamics are calculated for every grid within a watershed. Water and pollutants are routed daily throughout the watershed based on a unique and flexible algorithm that characterizes a watershed into many runoff travel-time zones. The mercury transport and transformation module simulates the following key processes: (1) mercury input from atmospheric deposition; (2) mercury assimilation and accumulation in forest canopy and release from forest litter; (3) mercury input from bedrock weathering; (4) mercury transformation in soils; (5) mercury transformation in lakes and wetlands, including reduction and net methylation; (6) mercury transport through sediment and runoff; and (7) mercury transport in stream channels. By using the grid-based technology, flow, sediment, and mercury dynamics can be examined at any of several points in the watershed. The model is capable of supporting large-scale watershed modeling with high-resolution raster data sets and will be used in mercury research projects sponsored by EPA. The model is programmed in Visual Basic and requires two ArcGIS (version 9.0) components—ArcView 9 and the Spatial Analyst extension.

Harris County is a natural flood prone region subject to a high degree of flood damage and risk. Due to the combination of flat terrain, impervious clay soils and subtropical annual rainfall average exceeding 48 inches, Houston has earned the moniker "The Bayou City". Regular flooding from the great flood of 1929 to Tropical Storm Allison in 2001 have caused significant flood related damages to the City of Houston, resulting in both economic and human losses. To combat the continued flood related losses, the State of Texas established the Harris County Flood Control District (HCFCD) in 1937, with the prime responsibility of overseeing the streams, rivers and bayous for residential and agricultural beneficial uses. As Harris County developed, increasingly complex watershed management issues developed, and HCFCD's role expanded to include cooperation with the US Army Corps of Engineers to complete watershed master plan studies and implement regional flood control and flood relief projects. As technology develops, traditional hydraulic and hydrologic methodologies are incorporated into geographic information systems (GIS), creating a more useful tool to both manage and develop planning tools to address watershed development issues. While GIS integrated watershed concepts are still maturing, many regulatory agencies, such as the HCFCD, are beginning to reap the benefits of GIS as a means to manage, update and track watershed development status and the hydrologic (flooding) aspects of that development. This paper describes the efficiency realized by utilizing GIS to manage several digital data sources and hydrology and hydraulics applications in the watershed master planning process.

The Mecca Hills at the southern end of the San Andreas strike-slip fault system exemplifies a transpression zone and provides valuable paleoenvironmental data for southernmost California to examine relationship between erosion and landscape development. Clarifying the relationships of the formation of such a transpressional region will help to construct and constrain regional erosion, sediment and landscape models. This study examines the relationships of faulting, fan sedimentation and watershed landscape development in Mecca Hills. The hypothesis of this study is that the extensional faulting related to the San Andreas Fault controls the fan sedimentation in the Northwest of the Mecca Hills. In the northwest region of the Mecca Hills, a succession of landforms, based on the aerial photographic interpretation and field mapping, two upland sections in the Northwest portion of the Mecca Hills were examined in detail to measure the faults, watershed fan sedimentation and watershed landscape evaluation. This study chose nine typical profiles that cross the fans, traces, and the washes to measure the distances and the angles, and then got the three-dimensional profiles maps for the reconstruction of the erosion, sedimentation, and landscape evolution processes. Through field surveying, mapping and aerial photos analysis for the examination of a succession of landforms in the study area, this study found that the San Andreas extensional faulting system directly influenced fan sedimentation as well as the watershed's landscape evolution in the study area. The findings of this study are that the landscape evolution is the result of a complex process in which a series of factors including climate factors, uplifting processes, and erosion processes occurred resulting in the landforms observed today. This paper is a pilot study for reconstructing the processes of erosion, sediment and landscape evolution of a proto-mountain range in the Mecca Hills.

Increased flood peak discharge and sediment load have been observed following the Cerro Grande Fire in Los Alamos, New Mexico. Because of concerns about the potential migration of radionuclides, a sediment transport model, HEC6T, was used to describe the observed scour, deposition and sediment transport in the wake of the fire. The model was then used to evaluate a grade-stabilization alternative in the portions of the channel, which the model predicted would be the most adversely impacted by post-fire scour. A five-year simulation was used to test the effectiveness of grade control—relative to taking no action. The simulation showed that the most upstream grade stabilization structure trapped the most sediment. Scour could occur below the structures. By causing sediment to deposit on the upstream side of the structure, the water flowing over the structure is able to scour because transport capacity is above the concentration in the flow. Overall, the simulations showed that grade stabilization can be an effective method for reducing scour. However, the design and emplacement of the structures requires analyses and interpretation accounting for hydrology, hydraulics, sediment transport and sediment yield.

Hydroelectric power was an early source of energy for the mining towns in central Arizona. One such facility, the Childs-Irving powerplant utilized Fossil Creek flow to deliver power during the early twentieth century. Later the Childs-Irving facility was incorporated into the Arizona Public Service (APS) power grid. In 1992, APS applied to Federal Energy and Regulatory Commission (FERC) for relicensing. Since 1992, APS has operated under temporary permits. In the fall of 1999, APS agreed to decommission this facility and return natural flows. From source springs to its confluence with the Verde River, Fossil Creek partially lies on the boundary between two national forests. The springs produce ∼1.22 m³/sec making it a major tributary for the Verde River. In a state where most of the native fish are extinct, threatened, or endangered, the opportunity to restore flows to a diverse native fishery is rare. Water emanating from the source springs is rich in calcium carbonate, which is expected to form cascading travertine dams along a seven km reach of the stream. The Forest Service, along with Bureau of Reclamation, the U.S. Fish and Wildlife Service, and Arizona Game and Fish Department, is implementing a native fish restoration project in Fossil Creek. The restoration treatment began in the fall of 2004 prior to return of full flows into the channel. Restoration of full flows will provide the Forest Service with an enhanced opportunity to reestablish a native warm water fishery in the Southwest. The decommissioning of the Childs-Irving facility has been and continues to be an arduous process due to the many entities involved, but the opportunity to restore a stream and its associated ecosystem in the arid Southwest is notable.

Water quality models like QUAL2E and WASP employ a constant hydraulic geometry to describe a river reach. However, hydraulic geometry is known to vary along pool to riffle sequences. This paper examines the magnitude of the hydraulic geometry variation between riffle and pool sequences for different flow levels and develops a mathematical model to simulate the downstream effects of the variation. The hydraulic geometry relationships—relating average velocity and cross-sectional area to discharge—were derived for seven hydrometric stations in a study of the Assiniboine River in Canada. These stations span a section of river 387 kilometers long, and each station has over 20 years of recorded flow data. There is a marked variation in the exponents and coefficients of the at-a-station hydraulic geometry. However, when the variation is mapped against riffle or pool sections, a graphical pattern of curves emerges. This pattern depicts the hydraulic reversal hypothesis, postulated by Keller in 1971. The curves show the variation in average velocity and cross-sectional area between riffles and pools for differing flow conditions. Distinct patterns emerge for each river reach. Subsequently surveyed cross-sections chosen to reflect riffle, pool and transition sections support the contention that the reversal pattern is unique for each reach. Water quality models simulate river reaches as uniform stretches exhibiting constant hydraulic geometry. However, river reaches show a variable hydraulic geometry due to riffle-pool sequences. This paper formulates a periodic function to describe the variability of riffle-pool hydraulic geometry along a reach. The function is incorporated into the mass balance equation and the resultant model applied to the Assiniboine River. Implications of the revised mass balance to water quality are discussed.

Raccoon Creek is a watershed of approximately 59 square miles northwest of the City of Rockford in Rockton, Winnebago County, Illinois. The lower two mile reach of Raccoon Creek at its confluence with the Pecatonica River lies entirely within the floodway of the Pecatonica River. The Pecatonica River is tributary to the Rock River with the confluence of Raccoon Creek at the Pecatonica River approximately 1.5 miles upstream of the Rock River USGS gage in Rockford, Illinois. Raccoon Creek is subjected to significant backwater influence from both the Pecatonica and Rock Rivers. During the 1970's local farmers excavated a channel south of the original meanders, presumably as an effort to alleviate some of the more frequent crop inundation due to the significant meandering of the lower reach of Raccoon Creek. Although the channel was excavated, the historic meanders were left almost intact in their original condition. Subsequent to the excavation work, significant downcutting was experienced along the excavated channel and flow ceased in the historic meanders. In the late 1990's approximately 700 acres of property, north of and adjacent to the lower two mile reach of Raccoon Creek, was donated and has become the Carl & Myrna Nygren Wetland Preserve, managed by the Natural Land Institute. The Natural Land Institute has begun a program of wetland and prairie restoration over the entire property. This paper presents the portion of restoration associated with the improvements proposed to re-hydrate the historic meander corridor. Also discussed are design challenges associated with restoration of almost two miles of historic stream corridor on Raccoon Creek.

Naturalized river restoration often attempts to reconnect channel and floodplain by manipulating the frequency of bankfull discharge. This research identifies limits to the geomorphic and ecological benefit of floodplain building in Syracuse, NY's armored and channelized Onondaga Creek given the community risk of flooding along with the imperfect method of establishing urban bankfull. The study reach of 300 meters, classified as Rosgen G4 and departed from a reference C3, has an estimated bankfull discharge of 31 m³ s^–1 yet was channelized to contain flows up to 85 m³ s^–1. While bankfull flow in rural areas builds and colonizes floodplain, such work is in conflict with, and undermined by, urban property, infrastructure, and emergency management objectives and activities. Urban restoration that abandons lateral migration must still use bankfull estimates to address sediment transport and fish passage, as well as avoid aggradation due to Onondaga Creek's upstream mud boils that can generate up to 27E3 kg of daily sediment loads. Unfortunately, urban geomorphic assessment of bankfull flow, the upper limit to prevent flooding, was difficult due to the absence of traditional indicators. In short, urban incised rivers need excavated floodplains in which to satisfy the ecological, geomorphic, and social functions. This research explores four methods for setting floodplain excavation targets, which are measuring available floodplain, stream shear stress, bank collapse, and channel effective discharge.

To prioritize data collection for characterizing transport of radionuclides in groundwater away from the Rainier Mesa/Shoshone Mountain area of the Nevada Test Site, a value of information analysis (VOIA) was conducted. A VOIA is an approach to evaluating data-collection alternatives that uses Bayes' theorem to estimate how the collected data would update our understanding of the uncertainties important to decision makers. With this approach, current uncertainties are described by prior probability distributions that the data collection activities modify into posterior probability distributions. To conduct the analysis, a generic pathline transport model was created from the Nevada Test Site regional groundwater flow and transport model. Statistical sensitivity analysis techniques were used to identify key uncertain parameters based on the results of probabilistic simulations. An expert panel was convened to assess prior probability distributions for the key uncertain parameters, identify characterization activities, and estimate the ability of those activities and groups to reduce uncertainty over the key parameters of the transport model. A Monte Carlo analysis using the transport model was used to develop prior and posterior probability distributions for the contaminant boundary. The activities and groups of activities were prioritized based on several Bayesian metrics summarizing the amount of learning that would occur in the contaminant boundary probability distribution vis-à-vis the cost of these activities. This paper summarizes the results from the VOIA presented in detail by Deshler et al.

As part of an ongoing program to improve performance assessment methodologies, we have used detailed numeric models to simulate groundwater flow and contaminant transport for a hypothetical geological disposal repository located at depth within a generic Canadian Shield watershed. The geology consists of low permeability intact rock, penetrated with high-permeability fault zones. Deterministic modeling of the steady-state groundwater flow regime within the watershed was performed on the 10 km x 14 km subject area. Within this area, particle tracking was used to generate time-of-travel (TOT) maps at candidate depths ranging from 200 to 900 metres depth over the entire model domain. The TOT maps were used to help select an example repository location and depth, and to determine surface water discharge zones for this repository. Discretization constraints associated with modeling of the fracture zones and of repository spatial features limited the maximum element size. These restrictions, when coupled with numeric and execution time and memory constraints, dictated that the domain of the transport model be minimized. The practical solution was to use a nested approach, with a vault scale transport model embedded within a discharge zone scale transport model, embedded within a watershed scale flow model. Transport modeling was performed for three release locations corresponding to locations of hypothetical defective waste containers. Radionuclide mass fluxes to a water-supply well and to surface water discharge zones were calculated for each release location.

In the late 1980s and early 1990s the research community and EPA began to focus on the constraints on aquifer remediation, particularly constraints related to Dense Non-Aqueous Phase Liquids (DNAPLs) as a secondary source of contamination at chlorinated solvent sites. By the late 1990s, a new paradigm was in general acceptance, where most chlorinated solvent sites were assumed to contain a difficult-to-remove, continuing DNAPL source, even at sites where DNAPL was no directly observed. The presence of this DNAPL presents a tremendous challenge "unprecedented in the field of groundwater engineering." One of the responses to this new paradigm has been to develop better technologies that can remove or destroy residual DNAPL and therefore deplete the source. A variety of methods have been tested, including thermal, chemical, oxidation, and biodegradation-based technologies. Despite the heavy financial investment in these approaches, there is an intense debate on whether these intensive source zone remediation technologies should be applied at many field sites. A U.S. EPA Expert Panel presented a qualitative decision process where the potential benefits from source depletion are evaluated using a "weight of evidence" approach. A list of potential benefits was presented, including: i) reduction of DNAPL mobility; ii) reduction of source longevity; iii) reduction of dissolved plume loading; iv) reduction of loading to receptors; iv) need to achieve cleanup quickly; and iv) intangible benefits. Quantitative results from a Department of Defense Strategic Environmental Research and Development Program (SERDP) project are presented to illustrate the performance of partial source depletion using thermal, chemical, oxidation, and biodegradation-based technologies compared to long-term containment. Planning-level models of source depletion at chlorinated solvent sites are used along with two new databases (a cost and performance database of source depletion case studies from the literature and a source response database from actual field sites) to compare the environmental and economic benefits and costs of partial source depletion vs. long-term containment.

The Anacostia River watershed has been severely impaired by urbanization and covers three political jurisdictions in the Washington metropolitan areas: District of Columbia, Montgomery County and Prince George's County. Over the last several decades, massive efforts have been made to improve the quality of the Anacostia River with limited success. More recently, a Low impact Development (LID) approach to manage water has been implemented through grants from the US Environmental Protection Agency (EPA) demonstrating how LID can be applied on a watershed scale. To accomplish this, a multi-jurisdictional Steering Committee was formed to oversee and coordinate the LID restoration activities. LID techniques can be used to control stormwater impacts from new development, redevelopment and watershed restoration. From a watershed restoration perspective, LID uses a holistic, terrestrial-based approach to retrofit urban areas within the Anacostia River Watershed rather then the more traditional approach of stream bank stabilization and streamside buffers. With the EPA's support, the restoration has moved to the third year. It is expected that additional grant funding will be available to continue restoration efforts. The elements of the restoration effort include: LID demonstration projects within the three jurisdictions, comprehensive monitoring programs, detailed Best Management Practices (BMP) modeling efforts, LID-BMP Demonstration Park, LID design competition, and a National LID Conference. This paper will provide an overview of these elements and demonstrate the restoration results. The outcome will show how several political jurisdictions within a watershed can work cooperatively to restore an impaired watershed and how LID techniques differ from traditional approaches.

In 1998, the U.S. Army learned a new way of thinking regarding stormwater management. This innovativestormwater management philosophy, low-impact development (LID), employs methods such as bioretention, pervious pavement reduction, green roofs, and conservation to mimic the predevelopment hydrologic regime. As a landholder in the Chesapeake Bay watershed, where nonpoint source pollution from stormwater runoff is a continuing issue, the Army wants to encourage the use of LID on its lands. The U.S. Army Environmental Center (USAEC) manages the day-to-day operations of the Army's Chesapeake Bay Program. In an effort to meet the program's goals of reducing nutrients and toxics, the USAEC worked with the Prince George's County, Maryland, Department of Environmental Resources (DER) and the U.S. Fish and Wildlife Service (USFWS) to design and install the first Army, Department of Defense (DoD), and federal agency LID demonstration project. This project included two bioretention areas at Fort Meade, Maryland, and was received enthusiastically by both the local and military community in the Chesapeake Bay watershed. Fueled by this enthusiasm, the USAEC launched additional LID projects in the Bay watershed and developed a training program designed to teach installation staff not only about LID and various LID tools and techniques, but also how to incorporate LID into installation plans, guidelines, and specifications and how LID fits into other programs and policies. The Army LID training also focuses on combining LID with conservation design to further minimize the impacts of development on the environment. These workshops were expanded to installations outside of the Chesapeake Bay watershed and have resulted in installation-funded LID projects.

The Pembroke Woods Subdivision is a ½ acre residential development located in northern Frederick County, Maryland, near the state line with Adams County, PA, and is not only the first Low Impact Development (LID) subdivision permitted in Frederick County, but also the first subdivision designed and under construction using the LID Design Manual developed by Prince George's County, Maryland. LID is an innovative approach to stormwater management (SWM) that attempts to mimic the pre development hydrology of a development site thus maintaining the hydrologic functions of the site and precluding the environmental impacts especially the water quality degradation of receiving streams, lakes and estuaries that are normally associated with land development activities. Because LID is a relatively new technology that substantially changes a number of the design paradigms used for stormwater management, one can anticipate a substantial learning curve for stormwater practitioners to understand and apply the technology. The Pembroke project site, being one of the first subdivisions designed and built with this technology, provides a valuable case study related to the issues that will be encountered in the application of this technology.

Low impact development (LID) is increasingly becoming an important option/alternative to be evaluated during the stormwater management planning process. An excellent example of the integration of LID into a stormwater master plan is the Celebrate Virginia North project; one of the first large-scale LID implementation projects in Virginia. The stormwater planning phase included extensive coordination between WEG, the client (Silver Company), the regulatory agencies, the locality, and interested stakeholders (Friends of the Rappahannock) in evaluating the potential direct and indirect impacts to the aquatic environment. We are presenting not only the consultant perspective of this project, but also that of the client, the U.S. Army Corps of Engineers (USACE), and Friends of the Rappahannock (FOR). Celebrate Virginia North is a master-planned community comprised of approximately 1,478 acres on the northern banks of the Rappahannock River in Stafford County, Virginia. This project has become a model in the Fredericksburg region for the implementation and application of innovative stormwater management approaches, through the cooperative efforts of regulatory agencies (USACE), local watershed groups (FOR), an innovative and receptive developer (Silver Companies), and local support (Stafford County). The stormwater management focus was directed to enhanced overall protection of the aquatic environment, including water quality and local stream channel hydrology. An innovative stormwater management plan for the entire master planned development was created by WEG that includes both regional stormwater management facilities, structural and non-structural practices, resource protection and preservation, and distributed stormwater controls. Due to the environmentally sensitive development, the USACE Permit conditions incorporate LID through the application of distributed integrated management practices (IMPs) within the England Run Watershed and the Central Watershed to infiltrate/filter/detain a volume equal to the volume of the first half-inch of runoff from 100% of the impervious cover of each planned land pod. These practices are in addition to conventional stormwater management measures required for the project. A minimum of 75% of the impervious cover of each planned land pod will be treated with IMPs.

In 2002, the Milwaukee Metropolitan Sewerage District (MMSD) began to explore the potential for Low-Impact Development (LID) techniques to help development projects meet the District's storm water management regulations. One general concern associated with using LID was the apparent complexity of determining the cumulative hydrologic effect of relatively small, interconnected LID components such as green roofs, bioretention cells, permeable pavements, etc. An adaptation of the Natural Resources Conservation Service (NRCS) unit hydrograph method was developed to provide an approach to the LID hydrologic analysis that remained relatively simple. This adaptation aggregates the LID retention volume across the site and treats that volume explicitly as a depth of runoff (i.e., excess rainfall) that must be exceeded before the convolution calculations generate a positive value for the runoff hydrograph. For practical purposes, this approach compared favorably against other alternatives, such as adjusting the composite NRCS curve number for the site, or treating all the retention volume as if it were an in-line storage volume situated immediately above the drainage area outlet. Calculations for the preferred approach have been formulated in a spreadsheet that allows the user to input the amount of retention provided by each of several kinds of LID components, and then see immediately a recalculated hydrograph that reflects the predicted effect of the aggregate retention volume. The spreadsheet, which has been dubbed the "LID Quicksheet", is expected to be incorporated along with its documentation into the MMSD stormwater management guidance.

Because bioretention areas have the ability to fulfill both landscape and water quality needs in a small area, they have received increased recognition as an integral part of Low Impact Development (LID); however, questions on design guidelines persist. Two paired, field-scale bioretention studies (Greensboro and Louisburg) have been conducted in North Carolina to study removal of phosphorus and nitrogen, hydraulic retention, the effectiveness of an induced saturated zone, and the impact of low P-Index fill media. Both bioretention pairs comprise nominally 5% of their respective watersheds and are planted with trees and shrubs. In Greensboro, one conventionally drained cell and one cell containing an induced saturated zone (previously termed anaerobic zone) of 0.45m were continuously monitored from June, 2002, to December, 2004. Lower outflow frequency was found for the induced saturated zone design. During outflow events, TP concentrations were significantly lower (P<0.01) than the conventional cell, although both designs increased outflow concentrations of nutrients. NO₃ concentrations were reduced by 77%; however, TKN and NH₄ concentrations were increased where the induced saturated zone was incorporated. In Louisburg, exfiltration, ET, and the significance of soil media for bioretention have been quantified by comparing outflow from two conventional cells constructed in winter of 2003 with non-agricultural soils. One cell was lined with 20 mil plastic; the other was unlined. During the summer of 2004, approximately 25% of inflow exfiltrated the cell, another 25% left via the cell's underdrains and 50% of the inflow was released as ET. Also in Louisburg, the non-agricultural fill soils resulted in average concentration reductions of 40–53% TP, and 25–60% TN for 10 storms.

Estimations of the average annual dissolved ammonia load to a small, urban watershed in eastern Massachusetts were made using a variation of the ESTIMATOR regression model. Comparisons were made between different time-step regression models applying either instantaneous or daily average flow values to point concentrations. In addition, comparisons were made between models with and without detailed storm data. Estimates of the average annual dissolved ammonia load from the basin are approximately 29,500 (95% CI: 21,000 to 42,000) kg NH₃-N/yr and 29,200 (21,000 to 41,100) kg NH₃-N/yr for models excluding and including storm samples, respectively. Without including storm sampling data, little difference is seen in the fit and load estimate using the different time-step models. Smaller time-step models with intensive storm sampling provide more precise load estimates than daily average time-step models or models with fewer storm samples. When designing a sampling strategy to make the most precise annual load estimate, efforts should be made to collect detailed storm samples if flow data is available in intervals smaller than the daily average, otherwise collecting one to two samples per storm is adequate.

To effectively and systematically analyze this complex spatial watershed system, a hierarchical optimization approach is proposed. A top-down land allocation scheme is applied to determine an optimal land allocation, and then to identify spatial locations of protected lands at a high level of spatial resolution (30 m cell). At the top level, the stormwater runoff simulation model is used to generate peak discharge pseudo data, that are input to a regression analysis, where the functional relationship between peak discharge and land-use variables is approximated as a quadratic function (R²=0.98%). This function is then used in an optimization model to allocate future land uses (urban, conservation, and agriculture at the subwatershed/catchement level), in a way that minimizes the resulting peak discharge at the watershed outlet. Then, an integrated hydrological-land use optimization (IHLUO) model scheme is developed to (1) investigate the NPS pollution generation/transport mechanisms and spatial variability/interdependencies of land use change impacts on watershed hydrology, (2) systematically evaluate different land-use patterns and their response to rainfall, and (3) search for the optimal land-use pattern at the cell level. The results are very promising, with a 44% reduction of the peak discharge rate as compared to the rate corresponding to the current land-use pattern. The most downstream and upstream areas are to be protected with more conservation, and most urban activities are allocated to the minimal impact subwatershed. Sensitivity analyses are performed and suggest maintaining at least 30% of the land in a conservation state, developing no more than 12% for urban purposes, and no more than 70% for agricultural purposes. The proposed methodology is applied to the Old Woman Creek watershed, located in the southwestern basin of Lake Erie (Ohio).

A distributed hydrologic model of an urban watershed in the northeast U.S. was developed and combined with a genetic algorithm (GA) to determine the optimal number and location infiltration-based best management practices (BMPs) for stormwater management. The distributed, event-based hydrologic model integrates the Curve Number method with a hydrologic network model of the catchment using a system of 4,533 hydrologic response units (HRUs). BMPs were conceptualized as elements that alter the infiltration/runoff partitioning of the HRUs to which they were applied. The results indicate that the optimal location and number of BMPs is a complex function of watershed network connectivity, land-use, distance to channel and contributing area, requiring an optimization approach of the type introduced here. A Pareto frontier describing the tradeoff between the number of BMPs, representing project cost, and watershed flooding is developed.

The Chesapeake Bay is the largest of 130 estuaries in the United States—its watershed covers 64,000 square miles and extends to six states (New York, Virginia, Pennsylvania, Delaware, West Virginia, and Maryland) and the District of Columbia. This summary analysis examines some of the environmental restoration efforts and reviews the primary stakeholders associated with the Chesapeake Bay, highlighting the formation and implementation of programs and policies. The Bay impacts economic, social and political areas of life including maritime and fishing activities, domestic and international transportation, wastewater facilities, hydroelectric plants and nuclear power plants, and national defense interests as well as recreation. Although the Chesapeake Bay's environmental condition may have improved slightly in some aspects over the past thirty years, the region's increased population density and land use, clearly, have impacted the Bay adversely. Today, more than 40% of all land in the region has been altered due to agricultural, commercial and residential development. Primary pollutants and ecological challenges include nutrient pollution; toxic chemicals; air pollution; landscape changes; sedimentation; overharvesting of marine life, i.e. oysters, crabs and fishes; exotic species (organisms not indigenous to the area); and threats to humans (Pfiesteria piscicida, Cryptosporidium parvum, exposure to toxins, and water pollution are the most prevalent concerns).

Fairfax County has initiated a comprehensive watershed management program for protecting and restoring the ecological health of streams throughout the County. The county adopted a collaborative approach for involving the community and for gaining support for the watershed plans developed through the program. Rather than reinventing the public involvement process for each of the County's 30 watersheds, a template for this process was developed and is being applied to each watershed project. As part of the scope of work for the Little Hunting Creek Watershed Management Plan, Woolpert LLP and the University of Virginia's Institute for Environmental Negotiation (IEN) developed the public involvement process guidelines for the County's watershed planning program. Since smaller watersheds will be grouped together, it is anticipated that the process will actually be applied to 15 separate watershed plan projects. The public involvement process used by Fairfax County consists primarily of the formation of a steering committee of diverse community representatives and key stakeholders for each watershed project. Their primary role is to advise each County/consultant project team and to play an integral role in conducting outreach to their own constituencies, and to help get the public to attend a series of four pre-defined forums or workshops: the Issues Scoping Forum, Community Watershed Forum, Draft Plan Review Workshop, and Final Plan Review Workshop. This approach promotes collaboration, encourages engagement of citizens, and helps to build consensus from the community throughout the development of each watershed plan.

The restoration of over 2,406 hectares (5,945 acres) of privately owned land to a naturally functioning wetland after 100 years of farming is providing the Indiana Natural Resources Conservation Service (NRCS) with many challenges. The overall goal of the Wetlands Reserve Program is restoration and enhancement of wetlands in order to achieve the greatest wetland functions and values, including optimizing wildlife habitat. Achieving these goals and satisfying the needs and priorities of the landowner, various private organizations and local, state and federal agencies has been demanding. To illustrate the complexity, the following is a partial list of issues being addressed during the planning phase of this restoration project: Elevation of a state highway that divides the site; fiber optic and high powered utility crossings; state floodplain regulations; limiting flooding surcharges on adjacent landowners; diverting discharges from two streams into the wetland while satisfying the policy requirements of the local drainage board; closure of county roads as a result of permanently flooded areas; meeting NRCS design standards for dikes and dams in the creation of wetlands; and the potential transfer of private land into a state wildlife refuge. This paper describes the roles of various private interest groups and local, state and federal agencies; and describes how meeting the jurisdictional guidelines and timelines of each is being balanced, touching on what has and has not worked for Indiana NRCS thus far in carrying out this project.

The Hellbranch Run is a major tributary to Big Darby Creek, a national and state scenic river recognized by The Nature Conservancy as one of the twelve "Last Great Places" in the Western Hemisphere. Increasing development pressures in Central Ohio are posing a threat to the integrity of the Hellbranch Watershed and Big Darby Creek. The Hellbranch Watershed Forum was created out of the need stressed by local officials to address stormwater runoff that contributes to flooding in the Hellbranch Watershed, and to decreased water quality in Big Darby Creek. The Forum is partnering with the Army Corps of Engineers Huntington District to develop the Hellbranch Watershed Forum Action Plan (HWFAP). Additional leadership and expertise is being provided by Fuller, Mossbarger, Scott and May Engineers. The plan will: a) establish a baseline of environmental conditions within the watershed; b) forecast future water quantity and quality conditions; c) recommend policies for overall watershed and stream protection to be implemented at the watershed level; and d) identify restoration opportunities throughout the watershed and evaluate one ecosystem restoration project for funding through the Corps. This paper presents the methodology, findings, conclusions and policy implications reflected by the first three goals of the HWFAP.

An EXCEL spreadsheet was developed to evaluate estimated peak discharges resulting from rainfall events in wildfire burn areas of Montana. This method, called FIRE HYDRO, is based largely on the USDA Natural Resources Conservation Service (NRCS) Engineering Field Handbook-Chapter 2 technology. The purpose of developing this procedure was to assist USDA NRCS and Forest Service personnel who were involved with post wildfire reclamation work to estimate design peak discharges for the recently burned areas during the 2000 and 2001 wildfire seasons. It uses the NRCS Runoff Curve Number procedure. A supplemental portion of this method offers suggested Runoff Curve Numbers based on land cover prior to the fire, degree of severity of the fire, and slope aspect of the land. Issues involving hydrophobic properties of the soil resulting from wildfire are also addressed. The method yields four varying perspectives for the Runoff Curve Number of the subject area including the pre-fire value, post-fire I (with potential hydrophobic soils influence), post-fire II (without hydrophobic influence but little re-emergent vegetal growth), and post-fire III (after one growing season post fire until fully recovered landscape). This method was employed as a means to analyze the hydrology of the burn areas in an accelerated fashion to facilitate a timely federal response to wildfire disaster areas in Montana and other western states.

This paper addresses flood retention by floodplain forests and the reduction of runoff by forested watersheds as a function of their management. The results from completed projects and the scheme of an ongoing project are presented. In 2001 reforestation measures were conducted to increase the retention potential of the floodplain of the lower River Blies in Germany. Due to the short project duration of about two years, which included planning and realisation of the measures, reforestation had to be restricted to sites that were initially owned by the project members. Thus only 2% of the floodplain could be included. This resulted in a simulated flood peak reduction of less than 1% at extreme flood events. Despite the relatively small mitigation effect in this particular case the project led to valuable findings. This refers for instance to the utilisation of floodplain afforestation as an ecological and flood control compensation measure, which might substitute lost retention volumes due to leeves or other structures in the floodplain. Another flood control project showed by simulation, that there is a potential for flood peak attenuation of up to 15% by reforestation of the total flood plain. Since 2003 investigations have been conducted into the runoff reduction effects of sustainable forestation and of decentralized retention facilities in woodlands. In two forested watersheds of 4.4 and 8.4 km² flood mitigation effects of such measures have been monitored and simulated.

EPA's Better Assessment Science Integrating Point and Nonpoint Sources (BASINS) is a multipurpose environmental analysis system designed for use by regional, state, and local agencies performing watershed and water quality-based studies. This system makes it possible to quickly assess large amounts of data in a format that is easy to use and understand. BASINS allows the user to assess water quality at selected stream sites or throughout an entire watershed. This invaluable tool integrates environmental data, analytical tools, and modeling programs to support development of cost-effective approaches to watershed management and environmental protection. All versions of BASINS to date contain a suite of GIS-based tools and operate in a GIS environment, using the GIS interface as the front end of the user interface. With each new version of BASINS additional data types have been added to the system. In addition, the analytical tools and techniques in BASINS themselves are continually evolving. The design of the watershed analysis system must support the addition of new data and new techniques for analyzing that data. BASINS is designed around an extensible architecture that allows for the addition of new data types and new tools. This design has proven effective during the development of versions 3.1 and 4.0. The National Elevation Dataset (NED) and National Hydrography Dataset (NHD) are examples of data types recently added for version 3.1. Currently additional data are being added from the U.S. Census of Population and the U.S. Census of Agriculture. New analytical tools have also been added, such as USDA-ARS's Automated Geospatial Watershed Assessment (AGWA). The core BASINS software does not have to be enhanced to support any of these new data types or tools. This flexibility enables BASINS to continue evolving to meet the changing needs of the watershed management community.

Streams impacted by agricultural grazing experience compromised functioning because of physical degradation and various pollutants (e.g., nitrates and fecal coliforms). The objective of this study was to determine if stream functioning could be significantly improved with the removal of livestock from the adjacent corridor. In 1999, four grazed pastures that contained meadow streams received streambank fencing through the Partners for Fish and Wildlife Program (treatment sites). These streams exhibited unstable streambanks and elevated nitrate and fecal coliform levels as a direct result of cattle impacts on the stream. Concurrent with streambank fencing, we established monitoring stations that were 100-m long within each stream. In addition, several control streams were monitored that had (a) no history of grazing and no fencing (control streams) or (b) a history of grazing and no fencing (control farms). At each station seasonal collections were made for benthic macroinvertebrates and fishes; and various water chemistry parameters (TKN, nitrates, ammonia, phosphates, fecal coliforms, and turbidity). Over the course of this study, nitrates have remained reasonably constant during the spring season and declined significantly during the summer and fall seasons; TKN, and phosphorus have not changed appreciably during the spring collection periods at treatment sites, but were slightly elevated during the summer sampling period. Turbidity has declined significantly during the spring sampling period, but remains elevated during the summer and fall periods. Fecal coliform concentrations continue to be quite high in treatment farm streams, but fluctuate seasonally. Treatment sites contain a good diversity and abundance of macroinvertebrates and fish that are comparable to those found in control streams. Our findings to date suggest that streams impacted by agricultural grazing may require appreciable periods of time to experience improved stream functioning.

The Czech Hydrometeorological Institute is a national agency responsible for water monitoring in the Czech Republic. The operation of the monitoring networks, data collection and their primary processing and storage in databases comprise basic activities of the hydrological service. Historically, the engagement of CHMI in water quality monitoring started in 1963, and was gradually developed into a state monitoring network of presently about 260 surface water and 460 groundwater sampling sites.

A modeling approach has been developed that identifies cost-effective detention pond configurations and land management plans for a watershed such that pollutant removal is achieved with a specified reliability level under conditions of uncertainty in pollutant loading factors. The design procedure incorporates reliability estimation into a genetic algorithm-based search procedure. This search procedure identifies cost-effective detention pond allocations (i.e., locations and sizes) that meet the pollutant removal targets at a specified level of likelihood and also allocates the land use development to meet system-wide land development plans. However, the implementation previously used was very computationally intensive and required repeated runs with different starting random seeds to find a good solution. In this paper, various constraint-handling methods, including penalty functions, multiobjective constraint handling techniques, and a new stochastic selection method, are applied to the reliability constraints and compared with respect to constraint satisfaction, quality of solution, and consistency. The results are used to provide guidelines for constraint handling techniques that perform relatively efficiently and consistently in evolutionary algorithms applied to watershed management under conditions of uncertainty.

A number of streams in the hill area of north central Mississippi have been experiencing varying degrees of instability for the last several decades. This instability, bed degradation and bank failure, has resulted in numerous problems including damage to local infrastructure, the loss of productive agricultural land, deposition in flood control channels, and environmental degradation. The Mississippi Delta Headwaters Project (formerly the Demonstration Erosion Control Project) administered by the Vicksburg District of the Corps of Engineers has been successful in stabilizing some of these streams. The Mississippi Delta Headwaters Project (MDHP) restores stream stability at a reasonable cost by addressing problems in the entire drainage basin, i.e. the systems approach.

The heavy rainfalls associated with the geographic location of Houston in the Gulf of Mexico, the mild slopes, and the clay or loam soil, render the city of Houston prone to flooding. Over the last few years, an increasing number of significant flooding events in the Houston metropolitan area resulted in major human and economic losses and created the need for further and more detailed analysis of the localized causes of flooding. Two are the major concerns related specifically to flooding in Houston: the rapid urban development of the last fifty years, expressed through major land use change and channel modifications, and the associated continuing subsidence. It is well documented in scientific literature that urbanization affects the drainage pathways of a watershed leading to faster responses to rainfall events and increased total runoff volumes and peak flows. Additional studies conducted in the growing Houston metropolitan area support the idea that land use change has a significant effect on the shape of the runoff hydrograph and can become a major cause of flooding. Furthermore, the increasing groundwater pumping rates necessary to support the municipal water demand of the growing urban areas have resulted to variable land subsidence, altering the drainage network by locally reducing or enhancing preexisting slope gradients. The current study focuses on Whiteoak watershed at Northwest Houston, TX. During the last thirty years, Whiteoak experienced both major land use changes and continuing subsidence. The first objective of the study is to set up a distributed hydrologic model representing the Whiteoak basin and calibrate it at different points (USGS gauges) along the watershed. The second objective of the study is to evaluate the hydrologic impact of land use change during the period 1978 through 2000. The final objective of the study is to assess whether the significant land subsidence of Northwest Houston affects considerably the response of Whiteoak bayou at Lakeview gauge, located close to the position of maximum total subsidence. The Lakeview gauge is situated in a populated area of upper Whiteoak where the bayou is currently capable of carrying approximately a 25-yr storm event before overtopping its banks.

Kerala, located in the southwest coast of India (latitude 8° 17'N and 12° 48'N and longitude 74° 52'E and 77° 227prime; E) is considered to be the land of waters as it has an average rainfall of about 3000 mm/year. Further the state has a large number of reservoirs and ponds, chains of backwaters. Despite this fact, Kerala is facing acute water scarcity for drinking as well as irrigation for the last several decades. Although the Ministries of Agriculture and Rural Development have implemented watershed projects for more than a decade, most projects have failed to generate sustainability because of the failure of Government agencies to involve the people. Both Government departments and Non-Government organisations (NGO) have been pursuing development activities quite independent of each other. NGOs tend to work more as independent implementers than as catalysts for bridging the gap between local people and the state. The watershed taken for the analysis is considered to be the first model watershed project initiated by the Western Ghats Cell of Planning and Economic Affairs Department of Kerala under the Western Ghat Development Programme in India with the concept of `Participatory Watershed based Integrated Development for Resource Management (PAWIDREM). This paper gives a narrative account of the processes, mechanisms, approaches, problems and biases that stakeholders had to face in planning and implementing this project.

Forests are one of the major land use type in India covering more than 20 percent of the land area. Tenth Development Plan of India 2002–2007 recognises the serious underestimation of economic and social values of the forests. The Plan targets to bring at least 25% of the geographic area of the country under forest cover by the end of Tenth Plan (2007) and 33% of the geographic area by the end of Eleventh Plan (2012). In many parts of India, livelihoods of rural and tribal communities are largely dependent on forests or forest related activities. In recent years, various committees have been constituted by the Ministry of Environment & Forest and Planning Commission for examination of forestry issues. None of these committees has their agenda to look into the vital issues of forestry altering the hydrological processes. There is a need to study the impacts of forest policies on hydrological processes and livelihoods of the local community. In the present paper, an effort has been made to generate a conceptual framework, which integrates the water yield assessment under various policy options and their socio-economic impacts. The Soil and Water Assessment Tool (SWAT) has been used with Arc View GIS interface to simulate the sediment and water yields for various forestry policy scenarios.

We assessed a 475-acre watershed in Charlotte, NC as part of a planning study to assess the capacity of the existing drainage system and to develop a capital improvement program. The purpose of this paper is to discuss some of the unique modeling techniques and software used to manage the data and develop the hydrologic and hydraulic models. Models were developed utilizing our Watershed Analyst software, which is a Geographic Information System (GIS) based interface between the watershed data and the models. Watershed Analyst is an extension to ESRI's ArcGIS platform and automates many of the routine calculations. The extension consists of toolbars and tools that extend ArcMap's environment and a model-generating engine. Tools and capabilities automate the hydrologic and hydraulic modeling process including the creation of spatial elements for basins, flowpaths, structures, x-sections and floodplains. The extension was programmed entirely in C#, an object oriented language similar to Java and a part of the .Net framework. Although the Watershed Analyst software utilized a digital terrain model (DTM) to perform the initial delineation, the subarea boundaries were verified and adjusted where necessary to correspond with the data gathered in field investigations. Other GIS data for land use, soils, and hydrographic features were used in the analysis to calculate curve numbers and time of concentration. Watershed Analyst extensions also calculated sub-basin properties for use in HEC-HMS. Hydrologic calculations are based on six-hour rainfall distributions for the 2, 10, 25, 50 and 100-year storm events. The HEC-RAS model was developed using the Watershed Analyst tools. The stream network has approximately 8,200 feet in three reaches. GIS was also used to prepare floodplain maps and compare results for different scenarios.

Potential utility of seasonal precipitation forecasts for water resources management was investigated for a wet forecast for the Fort Cobb watershed in central Oklahoma. Seasonal precipitation forecasts were expressed by ensembles of daily weather realizations, and corresponding watershed runoff was simulated by use of an artificial neural network model. Utility of a forecast was defined to be a function of the difference between runoff consistent with climatologic precipitation conditions and runoff consistent with forecast precipitation conditions. In general, runoff predictions were found to be useful for precipitation forecasts that departed by about 10% or more from normal conditions. However, average normal precipitation, antecedent hydrologic conditions, runoff response lag, and cumulative effects can dominate the forecast-based runoff prediction.

The development of a vault type stormwater treatment system that would achieve pollutant reduction to the Maximum Extent Practical (MEP) began in 1999. The Stormvault^TM Mitigation System has met that goal, utilizing the "Water Quality Capture Volume" (WQCV) sizing criteria as documented in "Urban Runoff Quality Management", WEF Manual of Practice No. 23 and ASCE Manual and Report on Engineering Practice No. 87. Third party monitoring of over 60 individual storm events confirms pollutant removal capabilities of Stormvault's ASCE sizing method. The tests document TSS pollutant discharge quality is superior to the listed removals comparable to traditional stormwater BMPs. The Mean WQCV is shown to be optimized to promote capture of approximately 86 percent of the average annual total suspended sediments in normal urban stormwater and detention time. The third party testing of the Stormvault^TM demonstrated that the ASCE "mean" WQCV criteria, utilizing the innovative patented baffle configuration, completely captures and treats up to 77% of the runoff hydrograph events for each design locale including the "first flush" of larger events. This ASCE mean event capture volume significantly reduces erosion and stream degradation from increased flows due to urbanization and helps restore pre-development runoff rates. Empirical calculations illustrate the Stormvault's ability to provide capture of TSS particles less than 70 microns in size and the retention of additional pollutants of concern such as heavy metals, nutrients and chemical oxygen demand.

King County (WA) Department of Natural Resources and Parks, Water and Land Resources is currently spearheading a comprehensive effort to model hydrology and water quality within the Sammamish-Washington and Green-Duwamish watersheds, which correspond to Hydrologic Unit Codes (HUC-8's) 17110012 and 17110013, respectively, and include all of metropolitan Seattle except areas that drain directly to Puget Sound. The Department's mission is to protect and restore the ecosystem beneficial to both the public and the environment within King County while, where reasonable, supporting similar efforts around the Puget Sound region.

This paper presents an application of a commonly used analytical model for the transport of a miscible contaminant in uniform, unidirectional ground water flow with three-dimensional dispersion, degradation or decay, and adsorption or retardation. The model simulates steady or non-steady state contaminant transport emanating from a vertical rectangular source of constant or decaying concentration in an infinite domain in the lateral and vertical directions and semi-infinite domain in the longitudinal direction. The source has a finite width and depth with its center coinciding with the origin of coordinates. It is found that the model, its steady-state version, and also an expanded version satisfy the initial and boundary conditions of the above transport process but do not seem to satisfy the respective basic advective-dispersion equations. The limitation and uncertainty about the validity and accuracy of the model predictions resulting from the above-mentioned mathematical inconsistency are identified.

This paper presents a brief review of three numerical and one Excel spreadsheet model for the transport of LNAPL in porous media. The numerical models include two finite-element models, ARMOS and MARS and a finite difference model, COMPSIM. These models use numerical algorithms to solve the flow and transport equations for water and LNAPL. The Excel spreadsheet model has been developed and published by the American Petroleum Institute (API) and is relatively simple to use. An example is presented illustrating the application of the API model for LNAPL recovery by a trench. In addition, practical limitations of the API model are identified.

In 1999, The Metropolitan Sewer District of Greater Cincinnati, Ohio (MSD) began negotiations with the United States Department of Justice, the United States Environmental Protection Agency, and the State of Ohio to create a program to address sanitary sewer overflows (SSO) and combined sewer overflows (CSO). The resulting document, the Consent Decree, formally outlined a process that MSD would follow and that government agencies could recognize and support. MSD had been addressing removal and reduction of SSOs and CSOs prior to the Consent Decree negotiations, but the Consent Decree defined a time frame as well for MSD. The Consent Decree required MSD to update the CSO Long Term Control Plan (LTCP). An important component of the CSO LTCP Update is the assessment of CSO control alternatives with respect to receiving water quality. As such, a field program was designed and implemented to support water quality modeling and CSO planning objectives. The field program would coincide with the water recreation season, starting in May and ending in October. The field program contained several components associated with dry and wet weather sampling and monitoring as outlined by the Consent Decree; Ohio River sampling, source characterization (CSO, SSO and Storm), and tributary sampling and continuous monitoring. This paper discusses the continuous monitoring component of the tributary sampling and monitoring program. Starting with the conceptual plan described by the Consent Decree, it outlines the process of converting a conceptual ideal into a workable field program including the installation, maintenance, data management and demobilization activities. Specific examples of unique site limitations are provided with the solutions tried and the resulting outcomes.

This research applies the fuzzy set theory on the transport of pollutant modeling, to find out uncertainties, presents in water quality analysis. The studying solves the advection diffusion equation, using the fuzzy set theory, defining membership functions, which will represent the concentration profile of the pollutant, in natural rivers. The results have shown that the fuzzy set theory could be a useful methodology to evaluate uncertainties, and to predict engineering risk analysis, concerning with environmental water quality problem.

Urban sprawl places watersheds and associated streams and rivers under increased stress in terms of impaired water quality from stormwater runoff. This study investigated the response of one wet and two dry stormwater detention basins to rainfall events to determine their effectiveness as sediment and nutrient processors. The study was conducted in James City County, Virginia, a county presently experiencing rapid residential and commercial growth. Using automated ISCO© water samplers, samples were collected before, during, and after rainfall events of variable magnitude. Samples were analyzed for the following: dissolved inorganic phosphorus, total particulate phosphorus, dissolved nitrate+nitrite, dissolved ammonium, total suspended sediment (TSS), and total dissolved sediment (TDS). Significant increases in nutrient concentration and sediment discharge from both wet and dry detention basins were observed during and after rainfall events. Dry detention basins, however, were less effective than wet basins in processing sediment and nutrient concentrations during the three separate rainfall events. In James City County there has been a recent policy push to install wet detention basins rather than dry basins. These data support such a change in stormwater management practices to maintain better water quality in developing watersheds.

Two green roofs were constructed and monitored in North Carolina's Neuse River Basin (WCC in Goldsboro and B&J in Raleigh). Data was collected from WCC from April 2003 to September 2004; B&J data collection began in July 2004. The hydrologic and water quality performance of two different green roofs were investigated. Each green roof retained a significant (p<0.05) proportion of the rainfall, peak outflows were significantly (p<0.05) reduced from the green roofs, and each green roof had substantial delays in runoff. Both concentrations and amounts of total nitrogen and total phosphorus increased from rainfall to green roof outflow and from the control roof outflow to green roof outflow. It was determined that the soil media, composed of 15% compost, was leaching nitrogen and phosphorus into the green roof outflow. This field study demonstrated the importance of green roof media selection in locations where nutrients are a concern.

The Western Washington Hydrology Model (WWHM) was developed for the State of Washington Department of Ecology by AQUA TERRA Consultants to size stormwater control facilities in western Washington, based on flow duration standards. The flow duration standard is better than the design storm frequency methodology for sizing stormwater facilities because it prevents an increase in the duration of erosive flows. The design storm methodology does not do this. The erosive flows are the flows that do the most damage to the receiving streams, streambanks, and adjacent properties. The WWHM computes stormwater runoff for a site selected by the user. The WWHM uses long-term local hourly precipitation. The model runs HSPF in the background to generate 40+ years of hourly runoff data. Stormwater runoff is computed for both predevelopment and post-development land use conditions. The WWHM routes the post-development stormwater runoff through a stormwater control facility of the user's choice. The Department of Ecology standards require that post-development flow durations not exceed pre-development flow durations for the range of erosive flows. The WWHM computes the required flow duration information and reports if the facility meets Ecology's standards. The available types of stormwater control facilities include standard trapezoidal pond, infiltration pond, tank (cylindrical, arched), vault, and irregular-shaped pond. The facility can be either manually sized or the user can use the WWHM pond optimization feature. The WWHM also allows the user to select appropriate low impact development BMPs (pervious pavement, roof runoff dispersion, infiltration, etc.) and evaluate their ability to reduce the size of the required stormwater control facility. The WWHM software can be customized for a specific jurisdiction (city, county, or watershed) in western Washington or anywhere in the U.S. to better represent the hydrology of the jurisdiction's watersheds and/or to include new criteria or standards and BMPs.

Research was conducted to compare different objective functions and optimize complex hydropower operation systems. Six functions were considered covering a large number of possibilities: (FO1) minimize the loss of the stored potential energy, (FO2) minimize storage deviations from targets, (FO3) maximize total energy production, (FO4) minimize spilled energy, (FO5) minimize energy complementation, and (FO6) maximize the profit derived from secondary energy. The optimization was performed using the SISOPT model developed by a team of EPUSP and UCLA researchers and uses different methods to solve the operational problem. The optimization can be solved by Linear or Non-linear methods. The non-linear model was selected in order to get accurate results. The sub-system selected for case study was the Paranapanema System, located in the south of the State of São Paulo. The objective functions were analyzed considering different hydrological series. A set of data was obtained for comparative analysis. The results showed that generally the objective function used to minimize the complementation of energy demand in the entire system produces more suitable operation policies for the hydropower system.

The Saint Venant's equations have been applied to study flood routing in natural rivers. However, considering that such models are deterministic, there are difficulties in finding ways to work with the inherent uncertainties in flood routing. To resolve that inconvenience, this research applies fuzzy set theory, on the hydrodynamics modeling, to figure out uncertainties, present in the flood routing. To do so, a set of membership functions was defined representing hydraulics and hydrologic parameters. In this way, the hydrodynamics model can be solved, yielding a membership function that represents the flow field in a river. The results show that fuzzy theory could be a very useful methodology to evaluate uncertainties, and predict engineering risk analysis concerning with flood routing processes in rivers.

The Center for TMDL and Watershed Studies at Virginia Tech (the Center) is committed to improving the quality and effectiveness of watershed planning processes, including TMDLs, as well as expanding the professional expertise needed for their development, evaluation, and implementation. The Center conducts basic and applied watershed planning and watershed management research, and provides educational programming tailored to the specific needs of stakeholders, government personnel, and technical professionals. Personnel associated with the Center provide expertise on scientific, engineering, sociological, economic, and policy issues related to watershed management and the TMDL process. The Center's mission, products, and services reflect the service-oriented Land-Grant University missions of teaching, outreach, and research. The Center is actively involved in developing TMDLs and TMDL implementation plans in situations where the methodology and guidance to develop such deliverables are not well defined. To date, the Center has developed 25 TMDLs in Virginia, addressing both bacterial and biological impairments. The Center has developed and delivered TMDL workshops to a variety of audiences, prepared supporting TMDL-specific extension publications, and developed and delivered a graduate level course in TMDL development and implementation. In addition, the Center has partnered with the U.S.EPA to develop a web-based TMDL knowledgebase, the TMDL Clearinghouse.

Turkey has been divided into 26 basins for studies related to water resources development. Surface areas of the basins range between 6,300 – 127,500 km², the average being approximately 30,000 km². Compared with nested watershed classification of U.S., the average size of Turkish national basins corresponds to the third-level (basins). Currently, a forth-level (sub-basins) with an average size of 1,820 km² reside below the basins in U.S. classification. Even these sub-basins are found to be too large to adequately serve many water resource management needs. Two additional levels (watersheds and sub-watersheds) are currently under development in order to solve this problem. Taking this fact into consideration, currently existing basins of Turkey are supposed to be too large for effective water resources management and there is a need for delineation of sub-basins in a scientific manner. In this study, the boundaries of proto-type sub-basins are determined by using DEM-based automated delineation techniques. For this purpose, 30 arc-seconds SRTM30 DEM is re-projected into an equal area projection, hydrologic sinks are filled and inaccurate elevation values are corrected. In order to prevent invalid delineation of closed basins that cover approximately 10% of the country, water bodies located at the center of these basins are extracted from Global Land Cover Characteristics dataset of USGS and excluded from the process. Among the alternatives, Deterministic-8 (D-8) algorithm with modifications by Garbrecht and Martz is used to calculate flow direction and flow accumulation grids. Using these grids, a set of candidate sub-basins are generated by applying different area thresholds. A threshold of 1,000 km² resulted in 359 sub-basins with an average size of 1,858 km², both of which are found to be appropriate and manageable for nationwide usage. Similarity of the average size of the delineated sub-basins to that of U.S. sub-basins also supports this result.

Since the 70s, the population of the São Paulo Metropolitan area has been growing at very high rates per decade. Due to the lack of urban planning and the illegal occupation of the environmental protection areas (around watercourses and on slopes), the percentage of impervious areas in the Upper Tietê River Basin, the main watercourse in the city, has increased significantly. As a result, flood frequency in the basin has also increased. The impact of impervious soil due to changes in the Soil Conservation Service "Curve Number" (CN) was estimated for a pilot area using Ikonos satellite images to quantify land use classes. A CN map was produced using the overlap between a land use map and a geological map. Then the surface runoff was simulated using the SCS runoff calculation technique.

Currently the Lynnhaven River and its tributaries in Virginia Beach, Virginia are in violation of the State's water quality standards for fecal coliform bacteria and dissolved oxygen in shellfish waters. As a result many segments of the river are listed as impaired on Virginia's 303(d) Total Maximum Daily Load Priority List. The Virginia Department of Environmental Quality (DEQ) has evaluated the water samples and has performed source characterization through a process called Bacterial Source Tracking, or `BST'. The data obtained for the Lynnhaven River Watershed indicate that as much as 25% of the fecal coliform pollution in the closed shellfish areas can be attributed to human sources. To better understand the problem, in 2004 the City of Virginia Beach took the initiative to investigate potential sources of sanitary wastewater that may be entering the Lynnhaven River via the storm drainage system. The City's consultant proposed an innovative technique to monitor human waste signatures. Optical brighteners monitoring (OBM) is a promising new technique to detect the presence or absence of human sewage in receiving waters. This paper will describe OBM as an emerging technique to quickly and cost-effectively facilitate a comprehensive survey of illicit discharge entering the storm sewer system. Furthermore, the paper discusses in-house testing, optimal selection of sites, detailed monitoring, and grab sampling.

We compared the variability in morphology and physical habitat characteristics between 14 stream reach pairs with forested and non-forested riparian vegetation in the Piedmont Physiographic Provence of southeastern Pennsylvania. Each pair consisted of nearly contiguous forested and non-forested 1^st though 4^th order stream reaches. One-dimensional hydraulic models were developed for the paired reaches using the U.S. Army Corps of Engineers' River Analysis System (HEC-RAS). The models were constructed using stream survey data, orthophotos, and flow estimates. Traditional statistical methods were unable to distinguish a difference in the variance of a habitat parameter (Froude number), while there was a clear difference in spatial correlation. Experimental and theoretical variograms were used to compare the variability of measured widths and predicted Froude number values in one of the forested and non-forested stream reach pair. Initial analyses suggest that there is more spatial correlation of surveyed width and predicted Froude number for the non-forested stream reaches. In our example, under similar flow conditions, a stream reach with forested riparian vegetation has more physical and spatial hydraulic complexity than an adjacent non-forested reach.

The drainage congestion in the Noakhali area is a long-standing and complicated issue. It is seen that large-scale siltation in the drainage channels due to reduction in tidal prism arising out of and subsequent manmade interventions (Crossdam I and II) are the causes behind such development. Due to manmade interventions in the past the south of the area has undergone major morphological changes resulting in channel and bay siltation. Thus new land formations have developed with the constriction and closure of major drainage routes. Some 200,000 hectare remains water logged for more than half of the year. This has led to severe environmental hazards in the area. Study has been undertaken to use mathematical modelling technique to analyze the complex problem and obtain a comprehensive solution. A 1-Dimensional sub-model for the area has been set up from the existing South East Regional Model of Bangladesh. The calibrated sub-model has been used to study various options of channel improvement and structural measures at the outfall channels. Later GIS flood depth maps have been produced to show the amount of improvement obtained in the various options. It has been observed that by controlling the outfalls of the rivers it has been possible to reduce siltation and flooding inside the area, but the major problem still remained outside the river outfalls where the discharge from the rivers and the tidal currents of the sea play a significant role in inducing the sedimentation process.

Regulated rivers present a challenge to river managers due to the presence of control structures, artificial channelization, flow regulation, and the resulting irregular sediment loading. The present study focuses on the Spokane River, Washington, USA, which is an urbanized, regulated river with high bed gradients and steep banks. Numerical flow and sediment simulation in the Spokane River is utilized here to examine multiple flow conditions that would not easily be studied in a field or lab setting. With the advancements in numerical modeling and data presentation, computer models are an attractive engineering tool. The objective of this study is to simulate the complex flow characteristics in the Spokane River through the use of two different hydrodynamic models, namely, FESWMS, which is a conservative 2-D depth-averaged model, and RMA-2, a non-conservative 2-D depth-averaged model. The best model for simulation of the Spokane River must be determined and some preliminary flow results will be produced. A set of evaluation criteria must be developed in order to make a proper choice for a simulation of this type, and this will require an in-depth examination of the underlying equations used in each model. The present study compares the utility of two hydrodynamic codes in simulating complex flows. The numerical results are compared with limited field and laboratory data.

This paper examines restoration practices that focus on the reduction of water temperatures in the upper mainstem Willamette River, Oregon, for the benefit of salmonid species. Economic information is developed to determine the cost-effectiveness of water temperature reduction strategies. The CE-QUAL-W2 water temperature model is used to simulate the effects of upstream combinations of riparian shading and flow increments on downstream water temperatures. Costs associated with these strategies are estimated. These costs consist of the opportunity costs of losing agricultural production and recreation due to flow releases from upstream reservoirs. Hyporheic temperature reduction is also examined. Restoration practices associated with this type of cooling are done through removal/reconnection of the obstacles that are necessary to allow the process of re-creating dynamic channel complexity. The observed reduction of summer water temperatures associated with channel complexity indicates that this approach is more flexible in reducing temperature than approaches that rely on flow increments or/and shade. Although the costs associated with the hyporheic approach are substantial, the effects of such a long-term ecological improvement of floodplain habitat may substantially benefit salmonid populations.

Twenty-five streams in northwestern Vermont spanning a range of geomorphic conditions were surveyed to determine the linkages between stream geomorphology, watershed condition and aquatic ecosystem health as part of an overall watershed classification project. Both field scale and watershed scale assessments were completed. At the field level, rapid geomorphic assessments (RGA) and rapid habitat assessments (RHA) were completed for all sites following Vermont Department of Environmental Conservation protocols. Detailed geomorphic and habitat assessments were also completed to provide quantitative data for each site. Watershed-scale parameters were evaluated using a geographic information system (GIS) and the Soil and Water Assessment Tool (SWAT) watershed modeling software. At the field-scale, data were assessed for relationships between the RGA and water quality, habitat quality and biodiversity. At the watershed-scale, we saw a broad trend relating RGA with average annual runoff, but the result was not significant. No trend was seen for annual average sediment loading. These results provide evidence that rapid geomorphic and habitat assessments done by trained individuals can provide useful information in managing and prioritizing watersheds and stream reaches for protection and restoration.

Livestock watering holes (i.e., dugouts) are typically constructed in floodplains, yet the influence of dugouts on native prairie fishes is unknown. Such information is necessary for the effective management of native fishes, especially species of concern such as the endangered Topeka shiner (Notropis topeka). The goal of our study was to suggest technical guidelines for constructing floodplain wetlands that are compatible with stream fish resources. Specific objectives were to: determine the flood frequencies of the connection between streams and dugouts; determine fish community characteristics in floodplain dugouts; and, associate dugout characteristics with fish assemblages. A total of 20 dugouts within Six Mile Creek watershed, South Dakota, were surveyed seasonally (excluding winter) from fall of 2003 to fall of 2004. Dugouts were categorized according to their lateral floodplain placement (connectivity with the stream and flood frequency of the stream-dugout connection) and longitudinal placement across the watershed. Fishes were sampled in dugouts and adjacent stream reaches with seines and traps. The 21 species making up the stream and dugout fish assemblages were similar. Fish inhabited 65% of the dugouts; 30% contained Topeka shiners. Most fish inhabitance, and all Topeka shiner occurrences, were in dugouts that were headwater sites and were either directly connected to the stream or disconnected and frequently flooded (average 1 in 2 year event). Two dugouts in this latter category contained the most abundant, self-sustaining Topeka shiner populations. Constructing dugouts separate from the stream within frequently inundated zones can provide off-channel habitat for fishes.

Ontario has joined other jurisdictions around the world in assessing ecological flow assessment methodologies. The need to better manage water takings in the Province was the impetus for the work. It has been necessary to raise awareness of the need to move from consideration of single, minimum threshold flows to consideration of a flow regime that can maintain the ecological integrity of aquatic ecosystems. Pilot projects have been undertaken in several watersheds in southern Ontario to evaluate the applicability of various ecological flow assessment tools to assign instream flow requirements. Using a bottom up approach, a variety of methods are needed to identify the flow required to satisfy various ecological needs including those required to sustain communities of aquatic organisms; prevent disruption of geomorphic processes; achieve water quality objectives; and maintain connectivity. Historic flow, hydraulic and geomorphic methods were applied in the pilot studies. The Range of Variability Approach in combination with detailed hydrologic modeling was also applied to assess the acceptable departure from natural conditions within a top-down approach. Further work is required to evaluate the potential for various techniques to be transferred to areas of the Province with different climate, physiography, and development intensity. Regardless of the methods used to assign flow requirements, a framework is needed that allows for adaptive environmental management and refinement of techniques and targets as knowledge of ecosystem responses is gained.

Invasive trees, including salt cedar and Russian olive, are actively being removed from the Middle Rio Grande riparian forest (bosque). The reasons for removing the invasive species vary from restoration to fuel reduction to recreation. In many instances, invasive trees along the banks are left in place to provide erosion protection. Conversely, several restoration projects have employed mechanical alteration of banks to promote over-bank flooding. The over-bank flooding allows the native vegetation to thrive and is necessary for germination of the native cottonwood trees. During the summer of 2003, with help from the City of Albuquerque Open Space Division, we established three sites to measure, monitor, and compare the changes in the bank of the Rio Grande with and without the removal of Russian olives. Russian olives were completely removed from one 12 meter section of river bank, while Russian olives were cut off near the base (leaving the roots) of a second 12 meter section. Another 12 meter section of bank was unaltered and used for a control site. Sixteen erosions pins (above and below the water level) at each of the three sites were installed and data collection began in June of 2003. During the summer and fall of 2003, erosion due to fluvial processes was negligible while wind and rain contributed to minimal erosion. The snowmelt season of 2004 caused a large increase in the Rio Grande water flow causing all of the erosion pins to be submerged. Monitoring erosion rates of the banks will allow for prediction of future erosion rates and their impact on over-banking.

There are increasing water demands along the Middle Rio Grande, located in central New Mexico, USA. The riparian vegetation (or bosque) uses a significant portion of water in the Middle Rio Grande, as much as 40% by some estimates. To complement existing eddy covariance instrumentation to estimate evapotranspiration, measurements of soil water content, temperature and suction are being made at five monitoring locations in the Middle Rio Grande. These measurements are used to estimate bosque soil evaporation, thus decoupling the soil water evaporation from the canopy evapotranspiration. Evaporation is being estimated from both interpreted soil water flux and a simplified energy balance approach using differential surface temperatures. Shallow water tables near the Rio Grande can potentially evaporate as much as riparian forests. Riparian restoration strategies aimed at water savings, such as removal of invasive non-native species, must consider the potential evaporation from bare soils.

At bridges, channel instabilities can cause undermining of the bridge foundations due to channel bed degradation, undermining and outflanking of bridge abutments and piles in the floodplain due to channel widening, and undermining of abutments and onset of local scour as the channel nears an abutment or floodplain pilings due to lateral migration. Thus, attention to channel conditions in the vicinity of bridges is an important aspect of bridge maintenance. Attention to the physical characteristics of bridge crossings in the various physiographic regions can lead to sustainable solutions to stabilizing channels at bridge-stream intersections.

A 90-year-old, 3.35 m (11-ft) high, concrete run-of-river dam is located in Vermilion County, Illinois on the Vermilion River. This dam has caused three drowning deaths in the last 10 years. To remedy the public safety hazard caused by the dam, the owner is analyzing modification or removal. This paper summarizes the preliminary investigation conducted by the Vermilion River Dam planning committee.

Although river restoration takes many different forms, one common goal of river restoration is the wholesale redesign of a reach. When this is attempted, the entire river geometry must be "redesigned", a process that includes specifying the channel's cross-section, slope, and channel planform morphology. The goal of this type of restoration is often to create a channel that is perceived as being "stable". In this context, the term "stable" usually implies that the river will not materially modify the design morphology during the design life of the restoration (whether this life is actually specified as part of the design or, more typically, left implicit). In practice, this means that erosion and deposition in the design reach will either be negligible, or else minimized so that erosion will be balanced by deposition, and the channel morphology will thereby be maintained. Additionally, (though it is rarely explicitly considered), stability also requires the channel to transport the sediment supplied to the reach without significant erosion or storage. If the restoration design involves placing substantial structures or planting riparian vegetation, then the design will not be able to tolerate significant erosion or deposition, and "stability" actually requires the channel to change as little as possible through time. The goal of this paper is to review some historical origins of the geomorphic concept of fluvial equilibrium, and to evaluate the validity of this idea as a current paradigm in fluvial geomorphology.

Widespread use of instream structures in the United States occurred as early as the 1930s under the direction of the Civilian Conservation Corp. Specific designs of instream structures were well developed in the 1930s with prototype versions of most currently employed designs. The Civilian Conservation Corp and U.S. Forest Service helped to standardize the designs in the 1930s and subsequent decades, and promote their use throughout the country. Many modern designs of instream structures show little or no variation in materials, construction methods and placement specifications relative to the 1930s prototypes. Consequently, surviving instream structures from projects in the last seventy years provide an opportunity to assess the long-term stability and morphologic impact of these devices. Field studies in the northeastern U.S. show that decay of structures can create site conditions that adversely impact aquatic and riparian habitat. Loss of streamside trees and reduced bank cover were both noted with certain designs of instream structures. Additional literature-based findings show that instream structures require expensive yearly maintenance to insure continued function of the devices as designed. These results show that the use of instream structures do not always provide a cost effective long-term approach to channel-restoration design. Furthermore, the detrimental long-term impacts of certain designs of instream structure may reduce the amount of specific habitat areas stream managers try to enhance.

Restoration of riparian, or streamside, forests has become a major focus of watershed initiatives throughout the United States as a means for improving water quality, temperature regimes, and in-stream physical habitat. Despite these benefits, the influence of riparian vegetation on stream channel width is not fully understood. One of the earliest studies on this topic found that channel bed widths were larger in reaches with forested riparian vegetation than in reaches with "sod," or grassy riparian vegetation along the same stream. Our study offers a unique opportunity because it capitalizes on a historic data set collected in the Sleepers River Research Watershed in Danville, Vermont in the 1960s. This historic data set contains hundreds of bed width measurements for several tributaries in the Sleepers River Watershed that once had a diverse patchwork of forested and non-forested riparian vegetation. For example, approximately half of the riparian zone along a small, unnamed stream (W-12) was forested in the mid 1960s with seven distinct forest patches. Today, one large patch of forest occupies nearly 80% of the riparian zone of W-12. Changes in the bed widths of W-12 were evaluated following this 40-year period of riparian reforestation. We revisited approximately 300 locations along W-12 and portions of upper Pope Brook to measure bed widths. Our results were consistent with many studies that have found that forested reaches were wider than non-forested reaches. Furthermore, reaches with recently reforested vegetation have widened since the mid 1960s; however, they were not as wide as reaches that have been forested from at least the 1940s Stream channel widening in response to riparian reforestation may have significant and previously unforeseen consequences for restoration initiatives.

Water resource management is becoming a necessity as more of the nation's wetlands and headwater streams are being impacted by development. An important management tool for protecting water resources is avoidance and minimization of direct impacts, which is mandated through federal and state regulations. Fixed width stream buffers and storm water management to treat non point source pollutants and control discharges are two additional management tools used protect water resources. These methods can be effective, but may neglect to address specific indirect impacts to stream stability, wetland function, and the function of the system as a whole. Indirect effects of development within a watershed include the changes to the stream's hydrograph and internal stresses, which induce morphological changes to stream channels over time. In 2001, two projects that used avoidance and minimization of direct impacts to the greatest extent practicable during the planning and design process were constructed. One project converted 73 acres of forested land adjacent to a large forested wetland system, which provides habitat for rare threatened and endangered species to commercial development; the other converted 45-acres of mixed pasture, open and forested land and sparse residential development adjacent to wetlands and a headwater stream to commercial development. Construction of both projects was completed in February 2004. The headwater stream that receives runoff from the development site was monitored for stream stability and water quality during and after construction to document changes in stream morphology resulting from the changes in the watershed. The monitoring program will continue for several years to measure and evaluate trends in the morphological changes. The goal of this study is to develop a tool that allows water resource managers and regulators to better control indirect impacts to water resources by considering the characteristics of the watershed and stream morphology when determining the appropriate avoidance and minimization strategies to protect water resources.

The number of stream restoration projects has increased dramatically during the last decade, especially in the New York City watershed region, where stream management to improve water quality is a high priority, and where the NYC Department of Environmental Protection and the Greene County Soil and Water Conservation District have partnered to develop a set of restoration demonstration projects. In this paper, the effectiveness of stream restoration projects in reducing stream bank erosion in the Batavia Kill watershed (Greene County, New York) is evaluated. This evaluation is based on a multivariate regression model to relate stream bank erosion rates to various explanatory variables including instruments representing geomorphological characteristics, flow conditions, rainfall conditions, temperature, the vegetation index, soil erodibility, and sediment characteristics. The general to specific approach is used to specify the regression model. A range of statistical tests is applied to check the model accuracy and the validity of the regression model. The results of these tests show that the stepwise regression model accurately predicts stream bank erosion rates on the Batavia Kill stream. The regression model is then applied on the project reaches, assuming there was no stream restoration to predict the stream bank erosion. It is found that the measured erosion on the restored reaches is much smaller than predicted erosion in the "without restoration" case, which means that the effectiveness of stream restoration in reducing bank erosion in the Batavia Kill watershed is significant.

This paper presents a modeling approach that establishes cause-effect relationship between individual pollution sources and in-stream water quality. It introduces a conceptual model of constituent network that mimics in-stream water quality dynamics. The network consists of water quality constituents (e.g., nutrients, DO, algae) and links among the constituents, which are the fundamental processes that convert chemical/biological mass from one constituent to another (e.g., algal growth). The network structure allows implementation of a tracking algorithm that quantifies the mass flux transferred among constituents via the processes. Impact of a pollution source is viewed as mass flux propagating through the constituent network and is quantified by the tracking algorithm. This approach makes differentiating impacts of individual sources on water quality feasible. In addition, the approach can be used to examine interactions of multiple pollution sources and their effects on reaction kinetics. Monitoring propagation of the mass flux in each river segment also can help investigate how small-scale process dynamics affects large-scale watershed response such as pollutant export from the river system. The proposed methodology is useful for assisting regulatory programs such as the Total Maximum Daily Load (TMDL) for setting load/wasteload allocations and nutrient trading. It also is a useful tool for formulating effective best management practices and developing watershed management plans.

A conceptual framework to link ecological response with the dynamics of fluvial processes, habitat maintenance, and sediment characteristics is presented that organizes relationships between biological and physical environmental domains. In human-dominated watersheds in which the sediment regime is in disequilibrium, the proposed framework promotes two important ideas. They are that 1) ecological impairment due to watershed disturbances is species dependent, expressed individually by the organism's species traits and life histories; and 2) the relationship between ecological impairment and sedimentation is dependent on sediment particle size class. Relationships between ecological impairment and transported particle size classes may be direct or indirect. The goal of introducing this framework is to advance our ecological understanding of impacts from sedimentation and habitat alteration in streams. In particular, researchers and practitioners need to question whether ecological impairment can be related to a single sediment yield threshold as designated for some specified discharge. Advancement of our thinking in this area is critical to develop sediment TMDLs that can be related to the loss of ecological functions.

Water quality impairment due to high mercury fish tissue concentrations and high mercury aqueous concentrations is a widespread problem in several sub-watersheds that are major sources of mercury to the San Francisco Bay. Several mercury Total Maximum Daily Load regulations are currently being developed to address this problem. Decisions about control strategies are being made despite very large uncertainties about current mercury loading behavior, relationships between total mercury loading and methyl mercury formation, and relationships between potential controls and mercury fish tissue levels. To deal with the issues of very large uncertainties, data limitations, knowledge gaps, and very limited State agency resources, this work proposes a decision analytical alternative for mercury TMDL decision support. The proposed probabilistic decision model is Bayesian in nature and is fully compatible with a "learning while doing" adaptive management approach. Strategy evaluation, sensitivity analysis, and information collection prioritization are examples of analyses that can be performed using this approach.

This paper describes a recent EPA-sponsored study (Imhoff et al., 2004) that analyzed and compared the capabilities of advanced chemical bioaccumulation models that are currently available to support the evaluation of ecological effects in aquatic ecosystems. These models are commonly used to establish the linkage of a variety of water quality targets and sources, and to provide a means for comparing various watershed and waterbody management strategies. EPA's Office of Research and Development (ORD), National Environmental Research Laboratory (NERL), Ecosystem Research Division (ERD), is currently supporting EPA's Office of Emergency Response and Remediation (OERR) by addressing priority research needs related to assessing the fate and transport of pollutants via contaminated sediment and bioaccumulation. The results of the first support effort by ERD, an evaluation of currently available numerical models useful for assessing fate and transport of contaminated sediments (Imhoff et al., 2003), were presented at the fall 2003 WEF TMDL Conference (Imhoff, 2003). The work effort presented in this paper constitutes the second element of the support effort by ERD, a parallel evaluation of currently available numerical models useful for assessing chemical bioaccumulation. Eight models were identified that were judged superior to all others in their promise as tools for chemical bioaccumulation analysis. To provide ERD with a basis on which to compare these models, a head-to-head comparison of the models was developed applying a high level of scrutiny to both model science and model usability. Finally, the study considered the issues and strategies involved in linkage of the bioaccumulation models to models of adjacent environment compartments.

The National Pollutant Discharge Elimination System (NPDES) stormwater program is taking on fresh significance now that Total Maximum Daily Loads (TMDLs) have begun to be implemented nationwide. This is particularly where states have adopted a "watershed approach" for implementing TMDLs. TMDLs prescribe pollutant load reductions specifically for Municipal Separate Storm Sewer System (MS4) outfalls. Further, watershed-based reductions of pollutants will apply to municipal stormwater permits on a "jurisdiction-wide" basis, providing the necessary mechanism to assure that reductions are implemented. In order to meet this incredible challenge, municipal permittees, in cooperation with the permitting authority, will be required rethink the way that watersheds are managed. Methods will likely appropriate comprehensive, holistic solutions involving non-structural as well as structural BMPs. It will also involve the re-examination of many of the practices that cities and counties currently perform to meet their NPDES stormwater requirements. Programs will shift their emphasis from simply implementing BMPs to a system that better quantifies pollutant reductions that are associated with management practices. New technologies will have to be tried, innovations explored, and a new paradigm will need to be embraced regarding the reduction of pollutants in the watershed. This paper provides a former regulator's perspective on what may be expected over the coming years, as TMDLs become a reality. It will also explore several creative new ideas for dealing with pollutant reduction requirements on a watershed basis, and how those ideas may be incorporated into MS4 permits in the future.

An innovative, risk-based approach to implementation planning for Bacterial TMDL compliance was developed by regulated agencies discharging to the Santa Monica Bay in Los Angeles County, California. This work was in support of the development of the Bacterial Implementation Plan, which uses an integrated water resources management approach, addressing multiple pollutants, beneficial use opportunities, and multiple agencies in its overall solution. The purpose of this analysis was twofold: first, to estimate the capture volumes of stormwater runoff that must be managed to meet the TMDL requirements; and second, to assist the agencies and stakeholders with the establishment of levels of confidence and risk in estimating stormwater runoff volumes and evaluating potential Implementation Plan alternatives. An ancillary, yet significant benefit of the method is that it allows for a collaborative and informed approach toward decision-making; this approach has been well-received by regulatory agencies and environmental groups. Many of the beaches along Santa Monica Bay were listed on California's 1998 section 303(d) list due to impairments for coliform or for beach closures associated with bacteria. The beaches appeared on the 303(d) list because the elevated bacteria and beach closures prevented full support of the beaches designated use for water contact recreation (REC-1). The California Regional Water Quality Control Board (Regional Board) implemented bacteria objectives using a "reference system/anti-degradation approach" which recognizes that there are natural sources of bacteria that may cause or contribute to exceedances of the single sample objectives. The Santa Monica Bay Wet Weather Bacteria TMDL (for Jurisdictions 2 and 3, which includes the County of Los Angeles, Cities of Los Angeles, Santa Monica, and El Segundo, and Caltrans), stipulates both rolling 30-day geometric mean and single sample limits, and provides for an "allowable number of wet weather exceedance days" (daily sampling). In the subject jurisdiction, 17 exceedance days are allowed. Preliminary sizing was estimated based on a review, analysis and ranking of 50 years of daily precipitation data, and the conversion of target precipitation rates to storage/treatment volumes. Associated with this target volume is a historically-based expectation of exceedance. To address hydrologic patterns, particularly inter-event storm patterns, intensities, and durations, a 50-year continuous hydrologic model was developed. This model simulates the effectiveness of the preliminary sizing approaches and offers insights to where water quality treatment approaches can be optimized. In addition the model provides for an evaluation of potential exceedance/violation so that an assessment of the criticality of such violations can be made.

The restoration of impaired waters through the Total Maximum Daily Load (TMDL) program requires contributing pollutant sources to reduce their loads to a level that will result in the attainment of the water quality standard. In-stream numeric endpoints represent the water quality goals that are to be achieved by implementing the load reductions specified in the TMDL. To date, the TMDL allocation scenario is considered as the starting point for development of an implementation strategy. Modifications may be required if the necessary load reductions are not achieved or if the water quality goals are not met. The likelihood of a successful TMDL implementation depends on a feasibleload allocation among the polluters. A load allocation scenario developed for a given water quality criteria may not be feasible due to limitations on the effectiveness of the available control measures. The practicality of the load reduction levels when translated into the relevant control strategies should be investigated to better ascertain the attainability of a given water quality standard. If one considers the technical limitations of accomplishing the high level of reduction required by many sate TMDL programs, the question arises: "Are the state standards for the designated water uses attainable?"

Gleick notes that "1.2 billion people live in a life of poverty without access to safe drinking water, and that almost 2.5 billion have no access to proper sanitation." Many in the international water community stress the importance of integrated water-resources management (IWRM) to address these challenges. They argue that this is the most effective means of sustaining economic and social welfare while protecting the health of vital ecosystems. One reaction to this call for more effective management has been the Hydrology for the Environment, Life and Policy initiative, or HELP. HELP has created a framework that enables water-law and policy experts, water-resources managers, and scientists to work together on water-related problems. HELP is a joint initiative of UNESCO and the World Meteorological Organization (WMO).

The Fairfax County Virginia Stormwater Planning Division is in the process of developing watershed plans for all 30 watersheds in the County. Early on in the project, Camp Dresser and McKee (CDM) reviewed the available GIS data, modeling needs, and available models to develop modeling protocols to be used in the preparation of the watershed plans. The goal was to develop accurate models appropriate for countywide watershed management planning within the budgets available to do this work. This paper presents the comprehensive GIS data that the County has available to do the modeling and the procedures that were developed for converting the GIS data to model inputs. Hydrologic, water quality, and stream models, GIS interface programs, and graphic display programs were reviewed. Based on this review, the County is using a combination of SWMM-RUNOFF, SWMM-TRANSPORT, and HEC-RAS to model the watersheds. Procedures were developed to model the benefits provided by the hundreds of regional and onsite detention ponds and BMPs in the County at a resolution and accuracy appropriate for watershedwide planning. Finally, procedures and protocols were developed to store the modeling results in GIS and database files for future use by the County. The goal is to provide an innovative model along with input and output datasets in a format that the County can use and update in the future.

The traditional training method of watercourses with closed conduits applied some decades ago is no longer environmentally acceptable. Nowadays all such projects are required to get environmental permit before construction, the natural state of watercourses should be preserved; open cross sections and materials friendly to the environment such as gabions, should be used in most cases. Existing structures and upstream control should be integrated in the final layout. Recently, programs have developed in Europe, e.g. Ecoflood, Daywater, investigating the possibilities of control at the source and restoration of the floodplains. However, this is not always feasible in heavily urbanized areas and especially for high return period floods. Determination of design discharges is an important factor. Design for a given return period is not uniquely defined and may vary considerably depending on the selection of the parameters and methodologies involved. New guidelines require higher return period for the design. In the case of watercourses with ephemeral flow data for calibration are usually not available. Thus, increased urbanization, higher design return period and way of computation result in higher design discharges than before. It is considered necessary to assure that the final design can handle discharges higher than the design discharge with reduced freeboard and that critical points, such as road and highway crossings are designed to handle higher return period floods with safety. Sensitive points of existing closed sections to pressurized flow should be identified and protected. It is proposed that hydrologic models are used that give the time and spatial distribution of peaks along with lag time estimations similar to those proposed by the hydrographs given in the Design of Small Dams.

Like many municipalities that have experienced significant growth from the late 1940's to the present time, Fairfax County's stormwater infrastructure information has been very piecemeal in nature. In order to support the development of management plans for the County's watersheds, the level of stormwater controls were estimated by querying real estate tax records in relation to when key stormwater management ordinances were enacted. In this paper we describe procedures used to generate estimates of the level of stormwater management controls countywide. The results of implementing the procedures within a GIS framework are presented. Preliminary evaluation of the results suggests the approach provides useful planning level estimates of controlled and uncontrolled areas.

In 1998 and 1999, federal and state environmental regulators issued water and wastewater permits for an evaporative-cooled combined-cycle gas-fired power plant. The plant is sited on a tributary of the Quinebaug River, which flows through Massachusetts and Connecticut, into the Thames River eventually discharging into Block Island Sound. One permit condition was to study ways to mitigate potential impacts to the river during low-flow periods. An analysis of historic U.S. Geological Survey (USGS) gauge records indicated that the median daily August flows, Aug Q₅₀, were higher before the construction of three U.S. Army corps of Engineers (ACOE) flood control/recreation lakes in the early 1960s. Because the Aug Q₅₀ was less after the lakes were built, the regulatory community hypothesized that lake evaporation was the cause. This paper examines this and alternative hypotheses and explains the cause of the change in streamflow regime.

Three rainfall-runoff events between September and October 2004 were monitored for a suite of structural BMPs, Low Impact Development designs, and manufactured BMPs. The range of 12 stormwater unit processes include: infiltration devices, filtration devices, treatment wetlands, conveyance structures, detention ponds, and manufactured BMPs; all of which were evaluated for water quality performance and storm volume reduction. Stormwater management strategies were tested in parallel, with uniformly sized unit processes targeted for a rainfall-runoff depth of 25.4 millimeters that is equivalent to 90% of the annual volume of rainfall. Under the parallel and uniformly sized configuration, a normalized performance evaluation is possible because unit processes of the same scale receive runoff from events of the same duration, intensity, antecedent dry period, and watershed. Water quality contaminants monitored include nutrients, hydrocarbons, metals, solids, and other routine parameters. Runoff constituent analyses routinely include total suspended solids (TSS), diesel range organics (DRO), nitrate (NO₃), phosphate (PO₄), chloride (Cl), zinc (Zn). A range of water quality parameters (temperature, dissolved oxygen, pH, conductivity) were monitored continuously as real-time data for influent and effluent waters. Previous research has demonstrated that treatment performance by stormwater control measures varies widely depending on both the design of stormwater treatment measures, as well as the variations in contaminant loading functions from site to site. In many cases it has been shown for stormwater BMPs that contaminant effluent concentrations exceed influent concentrations, particularly those major classes of stormwater devices functioning within the design criteria for treating 90% annual rainfall-runoff volume. The ranges of devices have distinct trends and performance differences.

The estimation of rainfall is an important factor in the design of civil engineering facilities and structures, such as dams, channels, culverts and storm drain systems. Historical precipitation data are used to develop methods to estimate future rainfall. Most often, the estimation of future rainfall is used to size and design facilities associated with control of storm water runoff. The storm of interest is usually a fairly infrequent event, such as the 10-year storm, the 100-year storm or the probable maximum precipitation. Therefore, the common methods of estimating rainfall focus on these infrequent events. There has been little investigation into the prediction of rainfall amounts for storms of higher frequencies, such as the amount of rainfall that can be expected once or twice a year or five times a year. This paper will discuss the current methods of hydrologic analysis in Albuquerque, and what precipitation input is required for those methods. Precipitation data for Albuquerque are analyzed in order to determine precipitation amounts associated with frequent events. Other relationships that result from the data reduction and analysis are discussed.

Regional stormwater management plans are comprehensive tools for addressing hydrologic issues in developing and developed watersheds. One of the challenges of creating and implementing watershed-based plans is the fact that watersheds cross municipal boundaries. In New Jersey, there are 566 individual municipalities, each with local jurisdiction over planning, zoning, and land use. New statewide stormwater rules and Phase II NDPES requirements have placed a burden on these municipalities, in terms of creating municipal stormwater management plans. Creation of partnerships between county-level agencies, municipalities, and academia is one way to address these regional issues. This paper presents the challenges encountered and lessons learned in developing Regional Stormwater Management Plans in several watersheds in southern New Jersey. Elements of these plans include detailed characterization and assessment of the watersheds, GIS mapping, hydrologic and hydraulic modeling, and working with municipal, county, state, and non-governmental stakeholders to craft scientifically sound yet implementable management plans.

Urban stream restoration is plagued with the risk of failure primarily because of a lack of understanding the differences between urban and rural hydrology. In addition, there are also much larger differences in regional stream restoration practices associated with the Quaternary history of floodplain and stream channel evolution. This paper is a continuation of Schlindwein (2004); unlike the previous paper, which concentrated on physical phenomenon, this paper will place stream restoration into a broader Quaternary classification and then compare and contrast policy and practice.

The Philadelphia Water Department (PWD) is breaking new ground in the development of an integrated watershed planning approach for their urban streams to address the objectives of several Federal and State programs dealing with Combined Sewer Overflows (CSOs), stormwater, Total Maximum Daily Loads (TMDLs), and habitat restoration. PWD's Office of Watersheds (OOW) has carried out an extensive sampling and monitoring program to characterize conditions in the Tookany, Tacony and Frankford Creeks watershed. The program is designed to document the condition of aquatic resources and to provide information for the planning process needed to meet regulatory requirements imposed by US Environmental Protection Agency (USEPA) and the Pennsylvania Department of Environmental Protection (PADEP). The program includes hydrologic and water quality analysis; and biological, wetland, and habitat assessments. A Stormwater Management Model (SWMM) has been developed for the watershed that can simulate the watershed response from storm sewers as well as combined sewers. The model has been adapted to simulate a wide array of CSO controls and stormwater Best Management Practices (BMPs). By simulating BMPs at various levels of implementation, graphs of urban BMP effectiveness in controlling CSOs and stormwater were developed and used to assemble cost-effective watershed management alternatives. The plan has resulted in a careful assessment of the potential for restoration of an urban stream. Under consideration are an array of CSO controls, stormwater BMPs, stream restoration measures, non-structural measures, and public education/participation programs. Implementation of the plan recommendations will be carried out in phases to allow for an adaptive management approach.

The Chino Basin is a large, adjudicated groundwater basin located in southern California. In 1998, a court order called for Chino Basin Watermaster (Watermaster) to develop an Optimum Basin Management Program (OBMP). Watermaster, given a two year time period, convened a process that was successful in the development of the OBMP, which is currently being implemented at an ultimate cost of over $400 million. One of the principle goals of the OBMP was to develop the maximum yield of the Chino Basin for the benefit of the basin's producers. This is being accomplished by increasing the recharge of local and supplemental water in the forebay areas, and by modifying pumping patterns in areas of historic discharge in an attempt to minimize discharge, induce more recharge, yet preserve sensitive ecological habitat and downstream water rights. Under construction are 21 groundwater recharge basins that will accept imported, recycled, and storm waters, and the second of two groundwater extraction and desalting facilities. These desalting facilities, when completed, will convert groundwater contaminated by 100 years of irrigated agriculture and dairy operations to 20 mgd of high-quality water for municipal supply. Watermaster and the Inland Empire Utilities Agency (IEUA) have been conducting monitoring and modeling investigations to guide the yield maximization programs. The programs and investigations have suggested that lowering the groundwater storage by about 200,000 acre-ft through a controlled overdraft, along with the expansion of the extraction and desalting system to 40 mgd, are necessary to maximize the yield of the basin.

This paper presents the results of a study which aimed to develop a Decision Support System (DSS) to support municipal agencies in its activities of urban water management. The DSS is composed of a data bank linked to simulation models and to output reports. The system can deal with three major aspects of urban water: hydrology, hydraulic of the main streams and water quality due to non point pollution. The DSS was developed for a small urban basin located in São Paulo city, the biggest city of the south hemisphere, Cabuçu de Baixo river basin. In order to obtain the basic information a set of field monitoring campaigns were conducted in the last three years involving hydrology and water quality measurements. It is important to point out the importance of this field work due to the lack of this kind of information for urban catchments mainly in a poor mega polluted city like São Paulo. In parallel to the DSS development a remote sensing study was necessary to analyze the urbanization and its impacts in the soil covering, hydrology and water quality. Finally the DSS was written in way that urban managers can use it for management activities without full knowledge of technical details of water simulation modeling.

The New York City Watershed is one of the most regulated water systems in the nation. The supply comes from a network of 19 reservoirs in a 1,969 square-mile watershed that extends 125 miles north and west of the City; it is the largest unfiltered drinking water supply in the nation. The Croton system, the City's first upstate supply, provides about 10 percent of the daily consumption from 12 reservoirs and three controlled lakes in Putnam and Westchester Counties. The other 90 percent comes from six reservoirs in the Catskill/Delaware system. The Village of Brewster (hereafter, VOB) is located within the Croton system in Putnam County, New York.

To meet the demands of growing populations, there has been increasing urbanization and associated developments in the watersheds of a number of streams. Urbanization in watersheds involves denudation by removal of trees and vegetation, alterations in land use due to construction of buildings, streets, and associated infrastructure, and rerouting of surface runoff by storm sewers and detention/retention basins. Most of the impacts of these developments occur on the hydrologic regimes of relatively small streams where the resulting increases in flooding and stream erosion may be significant. In general, there is reduction in infiltration and soil erosion and increase in volumes and peaks of surface runoff of the stream. This paper presents a comparative evaluation of the surface runoff hydrographs, sediment yield of the watershed, and patterns of degradation/aggradation of the stream before and after a portion of the contributing watershed has been urbanized with and without detention basins.

The Toenepi catchment (15 km²) is dominated by dairying, and ranges in elevation from 40 to 130m above sea level (ASL). Most of the catchment is flat land, with some rolling and steep land occurring on the boundaries. Annual rainfall is 1132 mm and mean annual temperature is 13.3°C. Well-drained Allophanic soils dominate in the catchment in close association with granular soils of moderate permeability. Poorly drained Gley soils occur in the lowest areas adjacent to the stream and require artificial drainage. The average stocking rate is 3.0 cows ha^–1, which graze all year. The catchment export of total nitrogen through the stream had been calculated in an earlier project as 35 kg ha^–1 yr^–1. The median total nitrogen concentration in the stream was 3 mg L^–1 (1995/97). To better understand nitrogen flowpaths, we initially installed groundwater monitoring transects in seven subcatchments, which reflected the major site and landuse conditions. Monthly sampling indicated that the concentrations of inorganic nitrogen in the shallow groundwater were generally well below the concentrations measured in the stream. This result would not support the hypothesis that the majority of the nitrate in the stream is derived from groundwater. Monitoring of the nitrogen concentrations in drains indicated that artificial drainage may be a major conduit for nitrogen into the stream. Artificial drains bypass the deeper subsoil and riparian zones where denitrification is likely to occur. A mathematical groundwater discharge model is used to quantify the proportion of streamflow that can be explained by groundwater discharge in contrast to near-surface flowpaths (surface runoff, artificial drainage). Understanding the pathways through which nitrogen enters Toenepi Stream is considered a prerequisite for the development of the most effective and efficient measures to reduce the N contamination of the stream.

The temperature of the Speed River near the City of Guelph in Southern Ontario is affected by an upstream reservoir, urban runoff, reduced baseflows, in-stream impoundments and development of riparian areas. Mitigating stream temperature increases in this system is desirable because of the direct effects of increased temperature on aquatic organisms but also because of the relationship between stream temperature and dissolved oxygen solubility. Dissolved oxygen levels downstream of the City's wastewater treatment plant are of particular concern despite high levels of treatment at the plant. Identification of other, less costly, means to sustain acceptable dissolved oxygen levels in the Speed River, in conjunction with nutrient control, would be of interest. The Stream Network Temperature Model (SNTEMP) was linked to a hydrologic watershed model (GAWSER) and applied to the study area to obtain preliminary predictions of the effects of various management practices on the thermal regime of the Speed River. A network of stream temperature loggers was used to calibrate the stream temperature model and identify specific locations on which to focus management efforts. Management practices evaluated were increased riparian vegetation, increased flows from an upstream reservoir, removal of existing in-stream impoundments and decreased stream width. Improvement of the performance of the model is desired along with application of a stream temperature model with a finer temporal resolution.

The planning models based on problem-solving procedures have been mainly applied to the field of watershed management in Taiwan and the rest of the world for decades. With increasing appreciation of the ecological functions and values to human society, the ecological engineering measures for stream restoration, hill slope stabilization, transportation systems and community development have been heavily encouraged within the planning and design stages of watershed management by the government in Taiwan. Therefore, the merge of ecological engineering measures into the framework of watershed management becomes one of the most crucial research topics for our local authority institutions. This study includes various natural, environmental, ecological, and social-economic factors in the model based on related research results and develops an integrated planning and design model of five stages: objectives of watershed management, watershed characteristics investigation, lineation of planning unit and analysis of engineering methods, allocation and design of structures, and ecological evaluation and extension education. Different from the planning models based on problem-solving procedures, the ecological considerations are emphasized through these five stages for the design of a sustainable ecosystem for the benefit of human society and natural environment. Also in this study, a study watershed with total area of 540 square miles (1412.5 square kilometers) is presented as an example for the application of this model. The operation procedures of several key model components, i.e. participation of local community, utilization of geographical information system, investigation and analysis of the ecosystem, habitat, and landscape, and allocation of ecological engineering measures, are illustrated in detail for better understanding on their values in the model. Finally, current conditions of implementation and monitoring for the study field are discussed to provide necessary feedback for on-going management projects.

The basic objective of this study was to improve upon univariate regression relationships previously developed between watershed stressors (e.g. imperviousness) and indicators of biological or geomorphologic condition. The approach was to conduct multivariate regression analysis to determine if more robust regression models exist between biological indicators (e.g. Index of Biotic Integrity), and physical, chemical and habitat stressors. Stream biological and physical habitat data were collected in Fairfax County, Virginia. The available data set contains four types of data: (1) general watershed data, (2) biological data, (3) water quality data, and (4) the stream physical habitat assessment (SPHA) data. The habitat data, infrastructure inventory data, and geomorphologic state data were collected on the Fairfax County Stream Physical Assessment project on about 800 miles of stream countywide in 2002–2003. The biological and water quality data were collected by the County under its Stream Protection Strategy (SPS) program during 1999 and 2001 at about 120 sites. A number of linear and non-linear relations were developed using SPS data for IBI as a function of percent imperviousness. It was observed that the maximum R² was 48%. The statistical study findings indicate that percent imperviousness plays an important role in the prediction of the Index of Biotic Integrity (IBI) and Total Habitat Score (THS). However, overall it is a much stronger predictor of IBI than of THS. It was observed that better explanatory and predictive relationships can be determined by classifying the data with respect to stream gradient, stream order, and physiographic province. Further, it was observed that individual THS metrics have better predictive capability for IBI than the THS. The highest correlation between imperviousness and individual THS metrics was for channel alteration, followed by bank stability and bank vegetative protection.

Water resource models used to support water allocation decisions usually include environmental concerns as hard constraints by enforcing minimum reservoir or streamflow levels. Because of the uncertainty in these models, a margin of error is often included which has the unfortunate consequence of effectively increasing the required minimum levels. Uncertainty arises from many sources including our incomplete understanding of hydrological processes, our inability to model these processes, incomplete data to derive site-specific coefficients for existing models, and inherent uncertainty in model inputs such as meteorological conditions. In this work traditional water resource models are recast using a probability network approach and expanded to include relationships linking streamflow and instream water quality to environmental quality parameters such as algal biomass. These relationships are empirically determined by using site-specific data to update more general relationships and to obtain uncertainty estimates in these relationships. A Bayesian Maximum Entropy (BME) approach is used to generalize results at monitored sites to other sites of interest and to identify areas where additional monitoring would be cost effective.

The effect of farming practices on water quality has been under increased scrutiny in Iowa. Overall water quality in Iowa has improved over the past 30 years, but the number of impaired water bodies in the state is not decreasing. Achieving sustainable watershed management can result in economic benefits to farmers and social benefits to the community, while preserving the ecological integrity of the aquatic ecosystem; it is through our research that we hope to elucidate better methods in order to meet this challenge. The Iowa River has been designated as an impaired water body since 1998 by the Iowa Department of Natural Resources. Coralville Reservoir, a mainstream impoundment of the Iowa River, is classified as a eutrophic lake and an impaired water body due to high bacterial concentrations. It is the primary drinking water source for Iowa City, Iowa. The Coralville Reservoir Water Quality Project was started in 1964 with the original objective of measuring the water quality of the river and reservoir. Continuous monitoring has yielded a data set of over 10,000 data points, allowing the detection of long-term water quality changes and providing insights into the natural and anthropogenic factors responsible for the changes. Preliminary analysis of the data set shows that the amount of nitrate-nitrogen in the reservoir has an increasing trend over a 30-year time span (1972–2003), while the amount of orthophosphate shows a gradual decreasing trend. Total suspended solids have decreased over the same period. Determination of the effectiveness of Best Management Practices (BMPs) on the available sediment and nutrient load by correlating historical and current rates of sediment loading to precipitation events, land use changes, agricultural practices and suburban development will be reported.

The preliminary findings of the ASCE/EWRI Task Committee on Runoff Curve Numbers are presented, and review comments, contributions, and critique are solicited prior to final submission. The major findings are given in condensed form in the major topic areas of: A review and restatement of the method; Development, analysis, and study results from field data; Current use and professional applications; Critique, and Summary.

Stormwater management criteria developed for the West Campus Cogeneration Facility (WCCF) on the University of Wisconsin-Madison campus attempt to address the growing problem of stormwater-induced flooding on Lake Mendota. Lake Mendota has an area of 15 sq. mi. (39 sq. km.) and a watershed of 233 sq. mi. (603 sq. km.), much of which is being converted from agricultural to suburban land use. The campus is located adjacent to the lake. Runoff from major storms can increase the lake level by several feet and flood lakeshore properties because of limited lake outlet capacity. Most urban stormwater reaches the lake within several days, but peak lake stages often occur from 5 to 10 days after major storms, due to runoff from the upstream watershed. Projected changes in land use will increase runoff, worsening this problem. Municipalities in the watershed apply stormwater peak discharge ordinances, but these approaches do not address the volume-driven flooding of the lake. Analyses of lake water level response to stormwater runoff inflow were used to develop stormwater design criteria for WCCF. These criteria stipulate that the majority of site runoff volume be released more than 7 days after the centroid of the rainfall hyetograph, for at least 50% of storms. In addition, runoff should be infiltrated to the extent practicable, to take advantage of the long travel times of groundwater discharge to the lake. Application of these criteria to the 14-acre (5.7 ha.)site included continuous simulation modeling of alternative system designs. The selected system incorporates surface and underground storage, with discharge to Lake Mendota via both surface and groundwater. The detention capacity is greater than "event-based" design approaches that local municipal ordinances would require. However, the analysis illustrates the complexity of defining performance for a system that is highly dependent on antecedent conditions.

In response to fish decline, many federal and state agencies (e.g., National Marine Fisheries Service (NMFS), United States Department of Agriculture (USDA), United States Bureau Reclamation (USBR), United States Forest Service (USFS), Department of Fish and Wildlife (DFW), United States Department of Energy and United States Army Corps of Engineers (USACE)) have employed management plans in the last twenty to thirty years to augment fish populations and other aquatic organisms by improving stream habitats. Most of the restoration efforts have focused on the enhancement of the stream corridors to restore habitat quality variables (e.g., pool-riffle sequence, depth, shade) and river geomorphologic characteristics (e.g., sinuosity and slope) within a stream corridor (microscale), believed to be important for fish, without considering the overall effects of watershed (macroscale) parameters on the instream parameters over time. Lack of understanding of the complex interaction between watershed parameters with instream parameters and the effects of scale on fish and aquatic species has caused, in some cases, the unsuccessful implementation of TMDLs and failure of these management plans. The long-term objective of this research will be the development of an integrated model that facilitates a rapid and versatile prediction of sediment transport within a watershed based on sound theory and the usage of robust models. This integrated model should account for the interaction between instream and watershed-wide parameters. It will incorporate an interactive suite of numerical models providing the capability to simulate hydrologic, hydrodynamic, and sediment transport/storage phenomena at multiple spatial and temporal scales. The paper presents the vision of the blueprint watershed integrative methodology.

Albuquerque, New Mexico, has experienced significant growth over the last 20 years like many other cities in the Southwestern United States. While the US population grew by 37% between the 1970 and 2000 censuses, the growth for Albuquerque was 83%. More people mean more development and increased problems of managing runoff from urbanizing watersheds. The U.S. Geological Survey (USGS) in cooperation with the Albuquerque Arroyo Metropolitan Flood Control Authority (AMAFCA) and the City of Albuquerque has maintained a rainfall-runoff data collection program since 1976. The data from measured precipitation events can be used to verify hydrologic modeling. In this presentation, data from a representative gaged watershed is analyzed and discussed to set the overall framework for the rainfall-runoff process in the Albuquerque area. Of particular interest are the basic relationships between rainfall and watershed runoff response and an analysis of curve numbers as an indicator of runoff function. In urbanized areas, four land treatment types (natural, irrigated lawns, compacted soil, and impervious) are used to define surface infiltration conditions. Rainfall and runoff gage data are used to compare curve number (CN) and initial abstraction/uniform infiltration (IA/INF) techniques in an Albuquerque watershed. The IA/INF method appears to produce superior results over the CN method for the measured rainfall events.

Beginning in 1997, a consortium of agencies and organizations began implementing the Kentucky Watershed Management Framework, a form of the USEPA's model for integrated management of water resources. The framework is intended to focus scarce human and financial resources on watersheds where they can be most effective, by means of a repeated five-year cycle of analysis, prioritization, and action. The Kentucky Water Resources Research Institute and the Kentucky River Authority coordinated the implementation of the Framework in its inaugural basin, the Kentucky River Basin. Now, seven years along in the process and halfway through the second five-year cycle, staff at the KWRRI continue to serve in the "basin coordinator" role. There have been many lessons learned along the way, most of which relate to the "implementation phase" of the cycle during which management activities are expected to occur within the prioritized watersheds. This paper provides an overview of the Kentucky Watershed Framework process as well as some general lessons that have been learned as a consequence of implementing the process in the Kentucky River Basin.

The Middle Rio Grande, a narrow strip of oasis in the southwestern United States desert, has been altered for centuries by humans. From Native Americans to Spanish Conquistadores to American Frontier settlers, the waters of the Rio Grande have been used for irrigation and the trees of the riparian forest (bosque) have been used for building supplies. With development of the American West came managed rivers and the Rio Grande was no exception. Once a river, subjected to extremes of drought and flood, carrying a large sediment load requiring a constant shift in course, the Middle Rio Grande is currently a well-channelized river with a regulated flow. The Middle Rio Grande and its bosque are home to two endangered species while the City of Albuquerque, with the largest populated area in New Mexico, straddles the river. Several governmental agencies and non-governmental organizations have started restoration efforts along the Middle Rio Grande. At the same time, the City of Albuquerque is in the process of changing its main water supply from groundwater to surface water. Although the quantity of water that Albuquerque will use is roughly the quantity of the Colorado River diversion to the Rio Grande, the Rio Grande through Albuquerque will have lower flows. In addition, construction of a small dam and intake structure in the river is underway. With all these constraints and activities, restoration is increasingly difficult in the urbanized areas along the Middle Rio Grande.

The Nez Perce National Forest and the Rocky Mountain Research Station are conducting a long-term study of road obliteration that includes measurements of sediment generated during obliteration activities. Three culvert locations in the Horse Creek drainage of Idaho were monitored during road obliteration activity. Sediment yields varied from 2 to 170 kg. Yields decreased rapidly downstream and at the mouth of each watershed sediment concentrations did not exceed 150 mg/L except during a precipitation event. Turbidity values exceeded the Idaho Department of Environmental Quality limit of 50 NTU above background immediately below the culvert, but not at the watershed mouth.

In August 2002, North Carolina passed the Central Coastal Plain Capacity Use Area (CCPCUA) Rule to regulate groundwater withdrawal from the Cretaceous aquifers in order to minimize serious water level declines and salt water intrusion that have been progressively worsening in these aquifers. The major groundwater impacts are being observed in two principal aquifers, the Black Creek and Upper Cape Fear, which have been desirable sources of high-quality, low-cost drinking water throughout this 15-County region. The regulations require groundwater withdrawals from the most affected portions of the region to be limited to 1997 withdrawal rates and may be further reduced by up to 75% over a 16-year period ending in 2018. The regulations are meant to avoid permanent damage to the aquifers and to help support economic growth in the region by having a sustainable water supply through development of alternative water supplies and by promoting water conservation and reuse. The North Carolina Rural Center undertook a study to determine the effects of the CCPCUA Rule, evaluate current and future water supply needs and sources, identify water supply alternatives, and estimate the costs of compliance for 122 public water supply systems affected by this Rule. If fully implemented, the CCPCUA Rule will directly impact over 40 public water systems and will result in the elimination of 38 million gallons per day (mgd) of existing groundwater sources. Replacement of these sources and development of alternative water supplies to meet future 2020 water demand is estimated to cost more than $250 million. Alternative water sources identified by the study include: 1) development of alternate groundwater supplies from underutilized aquifers; 2) development of surface water sources; 3) regionalization of water systems to allow more efficient use of existing water supplies; 4) water conservation, demand reduction, and water reuse; and 5) non-traditional sources such as brackish water, mine dewatering supplies, horizontal collector wells, and aquifer storage and recovery. Regional cooperation will be an important opportunity, allowing economy of scale in addressing aggregate demand, cost sharing, uniform rates, and bond-issuing authority.

Over two hundred and thirty watersheds throughout West Virginia are currently part of a Cumulative Hydrologic Impact Assessment (CHIA) project to determine the effects of surface and underground coal mining on stream water quality and quantity. The hydrologic watershed model, Hydrologic Simulation Program-Fortran (HSPF), is used, along with a GIS database and associated tools, to simulate stream discharge and those water quality parameters important in measuring the impact of AMD (Acid Mine Drainage). Satisfactory calibration of the stream flow component of HSPF had to be demonstrated, in spite of the data availability being limited to precipitation, air temperature, and potential evapotranspiration (PET) at each site. HSPF is a continuous deterministic model, requiring the estimation of more than twenty physically-based parameters. Because of the very limited availability of stream flow data, five gaged watersheds were selected to serve as calibration watersheds for the 235 CHIA watersheds, based on their geographic locations and similarity in characteristics. Four additional watersheds were chosen to test the validity of transferring the model parameters into non-calibrated watersheds. A joint calibration procedure, following the method used by R. S. Dinicola was used to find a common set of parameters for land use and cover across all watersheds. Two software packages, the USGS interactive Expert System for the calibration of HSPF and the automatic calibration program, Parameter Estimation with HSPF were used to aid in the calibration process. Although the initial calibration, and verification, was viewed as moderately successful, some watersheds still violated specific calibration goals. A new, physically-based, analytical relationship between the SCS Curve Number (CN) and a limited number of HSPF parameters is introduced to effectively reduce the number of parameters required, and to relate HSPF parameters to the CN method as used in mine site hydrology.

The numerical analyses discussed in this paper are part of a comprehensive watershed planning program underway in southeastern Pennsylvania. The goal of the Southeastern Pennsylvania Waterways Restoration Program (SPWRP) is to regain the resources in and around streams that were lost due to urbanization, both within the City of Philadelphia and in the surrounding counties. This paper presents a case study for the Tookany-Tacony-Frankford (TTF) watershed, an urban watershed in southeastern Pennsylvania. Because the watershed is highly developed, the potential for new development is limited. The watershed is a complex system that provides ample opportunities to develop and demonstrate a comprehensive watershed management program in an urban environment. The foundation of the current study is a comprehensive hydrologic and hydraulic model of the watershed including a sub-model of the combined sewer system (EXTRAN) and its tributary area (RUNOFF), and a RUNOFF representation of the drainage area tributary to the areas served by separate storm sewer systems. The stream system itself is modeled using EXTRAN, with open channels representing the natural stream cross sections. The RUNOFF and EXTRAN models of the combined sewered areas were developed and calibrated as part of the City of Philadelphia's CSO permit compliance program. The watershed-wide model calibration for this work was based upon continuous simulation model comparisons with historic observed daily streamflow. Simulated and monitored event volumes were compared and hydrologic parameters were adjusted to obtain a reasonable match across a range of storms. The resulting model simulates rainfall-runoff processes, flow in the sewer system, and flow in open channels. It was used to evaluate the technical merits of a number of watershed management alternatives, ranging from stormwater best management practices to CSO control measures to stream and habitat restoration.

Southern New Jersey is part of the Atlantic Coastal Plain, with generally flat topography and sandy soils. Hydrologic estimation techniques employed by state regulatory agencies typically rely on NRCS methods such as TR-55 and TR-20 with pre-defined runoff hydrographs. While these techniques work reasonably well in the steeper Piedmont regions of northern New Jersey, they typically over-predict runoff quantities in southern New Jersey by an order of magnitude. Several alternative unit hydrographs have been proposed for coastal plain regions, including the DelMarVa unit hydrograph, developed for the Delaware-Maryland-Virginia peninsula, and the Upper Maurice River unit hydrograph in southern New Jersey. To verify the applicability of these types of alternative approaches, a study has been conducted in support of developing Regional Stormwater Management Plans for several watersheds in the region.