Watershed Management 2010: Innovations in Watershed Management under Land Use and Climate Change

Global climate change is expected to alter temperature and flow regimes for streams in Wisconsin over the coming decades. Stream temperature will be influenced not only by the predicted increases in average air temperature, but also by changes in baseflow due to changes in precipitation patterns and amounts. In order to evaluate future stream temperature and flow regimes in Wisconsin, we have integrated two existing models in order to generate a water temperature time series at a regional scale for thousands of stream reaches where site-specific temperature observations do not exist. The approach uses the US Geological Survey (USGS) Soil-Water-Balance (SWB) model, along with a recalibrated version of an existing artificial neural network (ANN) stream temperature model. The ANN model simulates stream temperatures on the basis of landscape variables such as land use and soil type, and also includes climate variables such as air temperature and precipitation amounts. The existing ANN model includes a landscape variable called DARCY designed to reflect the potential for groundwater recharge in the contributing area for a stream segment. SWB tracks soil-moisture and potential recharge at a daily time step, providing a way to link changing climate patterns and precipitation amounts over time to baseflow volumes, and presumably to stream temperatures. The recalibrated ANN incorporates SWB-derived estimates of potential recharge to supplement the static estimates of groundwater flow potential derived from a topographically based model (DARCY). SWB and the recalibrated ANN will be supplied with climate drivers from a suite of general circulation models and emissions scenarios, enabling resource managers to evaluate possible changes in stream temperature regimes for Wisconsin.

In many developing countries, hydropower represents a significant contribution to the electricity generation matrix. In Chile, a combination of run-of-the-river and reservoir systems contributes approximately 50% to the total electric input, and plans for further development are under way, in order to match projections of a 100% demand increase in the next 20 years. Clearly, hydropower production is very sensitive to short- and long-term climatic variability. With many river systems showing annual streamflow coefficients of variation greater than 0.5, and with climatic projections indicating precipitation reductions for a large portion of the territory, hydropower vulnerability to climate change is an issue of great concern in Chile. The topic has economic implications, but also climate change mitigation implications given the role of hydropower as a substitute for carbon-based energy production. In this work we present a methodology for assessing climate change vulnerability of hydropower systems in Chile, based on hydrologic modeling, statistical analysis of historic generation and estimations of future behavior in an industry dominated by private utilities. The results presented here indicate that, over all, the Chilean interconnected electrical grid could face decreases of up to 20% in power input by the end of the 21^st century under the A2 SRES scenario. On the other hand power input reductions are smaller in magnitude than projected precipitation reductions, which hints at the potential for adaptation within the industry.

The Austin Water Utility (AWU) provides drinking water supply and wastewater disposal services to a population of more than 870,000 in Austin, Texas and several nearby communities. The AWU currently operates two water treatment plants with a combined production capacity of 1079 million liters per day (285 MGD) and 632 million liters (167 MG) of storage capacity. The utility also operates a wastewater collection and treatment system that consists of 4200 km (2600 miles) of sewers and two major advanced wastewater treatment facilities with a combined nominal capacity of 568 Ml/d (150 MGD). The utility's primary responsibilities include providing adequate water supply to meet both peak and long term average demands within its service area and to transport and treat wastewater generated in the area. While service population is a major determinant of these capacity requirements, the utility has noted a strong relationship among temperature, precipitation and water demand. As a result, long-term trends in climate means or variability could have a profound impact on the size and timing of planned capacity expansions and projected operating budgets and water conservation efforts. This paper identifies likely climate change scenarios and implications for the Austin area, some of which may already be underway.

This paper describes an ongoing U.S. EPA project to study the potential effects of climate change on water quality-based management plans and TMDLs. The project consists of two phases, the first of which is an examination of precipitation and streamflow changes that have occurred at selected sites across the Upper Midwest region. Assessing historic hydrologic changes (e.g., frequency, magnitude, seasonal variation) can help reveal ongoing processes and highlight factors to consider relative to climate change. The assessment of historic changes can also help to identify what information best describes potential future conditions for any given area, which is a significant challenge currently facing watershed managers (i.e., how will climate change affect specific locales?). The premise of this study is that an assessment of historical weather observations can provide a description of existing seasonal and spatial variability as well as trends that may be extrapolated into the future. To accomplish this objective, historic records of precipitation at several sites in the Upper Midwest will be examined, focusing on changes in annual precipitation, the percent of days with measurable precipitation, rainfall intensity, and seasonal patterns. Historic streamflow data is evaluated through the use of flow duration curves to provide insight into the type of effects climate change may have on TMDLs. Duration curves describe patterns across the full range of flow conditions. The potential effects of higher stream discharge due to increased storm intensity or lower flows resulting from more frequent droughts become apparent with duration curves. Because they are often used to define the loading capacity, duration curves represent a logical starting point to assess the implications of climate change on TMDLs. Rainfall-runoff models will also be used to examine the effect of potential changes in precipitation and temperature. In particular, rainfall-runoff models can be used to assess the sensitivity of a range of future scenarios based on historic data. For example, historic precipitation data can be increased by 20 percent across the entire year to evaluate the potential impacts to hydrology. The second phase of the project incorporates water quality information into the analysis. Information on loading rates for common TMDL parameters will be compiled (e.g., sediment, nutrients, bacteria) and the effect of hydrologic changes on these parameters will be examined as a starting point for describing potential implications relative to water quality. Many studies have described the effect of flow on in-stream sediment concentrations and loads. For instance, rating curves have been used to provide quantitative estimates of the relationship between flow and sediment. The potential effect of altered hydrology on water quality can thus be examined by applying a unit area sediment rating curve to duration curves that reflect pre- and post- climate change conditions.

Studies on the impacts of anthropogenic climate change have found that the magnitude and frequency of intense precipitation events are expected to increase over the next century. The goal of this paper is to determine the projected changes in Wisconsin's precipitation using statistically-downscaled GCM data and assess how those changes will impact the design of stormwater-related infrastructure in the state. The primary findings are that the magnitude of low-frequency, high-intensity events are projected to experience significant but modest increases, and the total amount of precipitation and frequency of intense events during March and April are projected to increase as well. Adaptation strategies for the increases in low-frequency quantiles are available, and additional hydrologic studies are needed to determine the potential impacts of the March and April precipitation changes.

The recently published Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) concluded that it is very likely that the frequency of heavy precipitation events will increase over many regions as our climate warms over the next century. The impact on the National Flood Insurance Program (NFIP) associated with a change in climate necessitates a thorough analysis of the effects of extreme precipitation and temperature events on flooding in the United States. This AECOM-Baker study being conducted for the Federal Emergency Management Agency (FEMA) seeks to quantify how the 1-percent-annual-chance flood (base flood used by FEMA for floodplain mapping) may change based on climate model projections through the year 2100. Also being considered in the FEMA study, but not discussed in this paper, are how projected changes in sea level and the frequency and intensity of coastal storms may affect the NFIP. Extreme climate indicators were developed previously as part of the IPCC effort to aid in quantifying the frequency and severity of extremes in temperature and precipitation and are used throughout this study to relate observed climate extremes to future extreme climate projections. The methodology also assesses the uncertainty of these projections by using multiple climate model data sets. Regression analysis was used to relate watershed characteristics such as drainage area, channel slope, basin storage, and impervious area, as well as observed extremes in climate, to the existing 10- and 1-percent-annual-chance flood discharges. The observed regression relationships were then used within a Monte Carlo sampling framework to determine distributions of how the 10- and 1-percent-annual-chance floods may change given uncertain projections in extreme climate and population growth. A regression equation that related flood depth to flood discharge was incorporated in the Monte Carlo simulation and was used to estimate the increase in the 10- and 1-percent flood depths, and the associated increase in floodplain boundaries. The results of this study will show the potential future impacts on the NFIP that result from projected climate change.

Large-scale rivers receive thermal discharges from a variety of sources including electric power plants. This thermal loading dissipates downstream, primarily via radiation, and convective and evaporative heat transfer to the atmosphere. Thermal discharges are typically regulated under the Clean Water Act National Pollutant Discharge Elimination System (NPDES) permit program. The discharge permits usually specify a maximum allowable increase in river temperature due to the discharge, often with the additional criteria of a maximum allowable river temperature. Permit compliance issues are often most critical during summer drought conditions, when the electrical production (and attendant cooling water discharge) is at maximum, ambient river temperatures are high, and river flow is low. Potential climate change could significantly alter the climate and hydrologic variables that are critical to dissipation of thermal loading, and regulation of thermal discharges. Changes in air temperature, humidity, and insolation could directly affect river temperature. Changes in precipitation depth and pattern could alter river low flow characteristics. Further, land-use changes, particularly in agricultural areas, could alter rainfall-runoff response from that which occurs at present. These issues were explored on a large-scale river through use of a hydraulic and energy balance model. The model reach extended for over 200 miles. Historical climate and river flow and temperature data were used to verify model results. Conditions of future climate change were evaluated by downscaling regional climate model projections to locations in the watershed, and using those results to alter the climatic input data to the river of thermal model. Potential changes in river low flow characteristics were evaluated via sensitivity analysis on historical low flows, due to the complexity of land-use/precipitation patterns/runoff rate interaction. The resulting "potential future scenarios" were used to evaluate changes in compliance to typical permit conditions. The analysis indicates that thermal discharge permit compliance could be significantly affected by future climate change conditions. The analysis also suggests additional analyses that would be appropriate to develop a comprehensive strategy for managing thermal loading under climate change conditions.

The short- and long-term effects of climate change have recently become a subject of active research in a variety of earth-science disciplines. The multi-faceted nature of changes in the physical system may also lead to changes in patterns of human activity, such as accelerated rates of water re-allocation and consumption. Such changes could be responsible for many undesirable consequences related to the quality of aquatic habitats in wetlands and estuaries. In particular, runoff and erosion processes in these areas are well known to be highly sensitive to variations in land use practices and precipitation patterns within the watershed. Because the corresponding processes originate at the watershed level, any numerical assessment of a potential impact on these areas must use an integrated approach capable of simulating atmospheric, hydrologic, and channel process components. Models simulating individual processes have already been implemented with moderate-to-satisfactory success. However, models integrating all three system components have not yet been developed. The apparent reason is the complexity of the process coupling, which involves vastly different temporal and spatial scales. Another reason coupled models have not been developed is the processes cut across several disciplines. This study develops a novel tool that approaches the problem by integrating large-scale watershed hydrologic processes with a hydrodynamic model and an evaluation model of biological function. A blueprint methodology for evaluating long-term changes in streamflow, channel morphology, and fish habitat quality is presented for a case study watershed located near Manchester, MI.

The U. S. Army Corps of Engineers (USACE) is undertaking a series of studies to support a pending decision by the United States pertaining to the future of the Columbia River Treaty with Canada. The Treaty, ratified in 1964, is an agreement between the United States and Canada to provide flood control and power benefits for both countries. In these studies, information will be developed and alternatives evaluated that provide the basis for long-term recommendations pertaining to the future of the Treaty. Assumptions drawn regarding potential future climate changes and associated hydrologic impacts could have very significant influence on alternative Treaty strategies. For several decades climate scientists have provided an increasing array of knowledge and information on climate impacts. Climatic phenomena, such as summer and wintertime droughts, floods and wind storms, have greatly affected the Pacific Northwest in the last several decades. Observed data in the West is already showing signs of global warming — reductions in spring snowpack, earlier spring snowmelt, increased runoff in winter and less runoff in summer. These shifts may potentially increase flood risks in the early spring, and change the timing and volume of water in spring and early summer available for reservoir refill. Different parts of a basin may be affected differently by warming so that high elevation snowpack may experience minor impacts while low elevation sites may experience major changes Water resource managers have struggled to understand how to incorporate the knowledge provided by science into their planning and operations. This paper discusses a decision-making framework to bridge the gap between climate science and water management for the Columbia River Treaty 2014/2024 Review. The decision framework must be robust enough to accommodate risk characterization, screening and prioritization while allowing for adaptive management strategies that avoid maladaptations. Maladaptions are decisions that prevent or constrain the ability of others to manage, reduce or otherwise adapt to the effects of climate change in the future. Modeling systems used by the team will be capable of incorporating multi-objective analyses and alternative assessments running numerous future climate scenarios in physically based hydrologic, reservoir and hydraulic models that will ultimately support the decision-making framework.

The United States National Forest System supplies much of the nation's drinking water. However, changes in climate, land use and population are stressing the ability of these forests to provide that ecosystem service. Federal land managers are under increasing pressure to increase ecosystem carbon sequestration in an attempt to partially offset greenhouse gases and slow global warming. Unfortunately, the positive relationship between carbon gain and water use in forests, puts the need for water and increased carbon gain at odds with each other. To assess these tradeoffs, a coupled water supply and demand, carbon sequestration, and biodiversity (WaSSI-CB) model was developed. WaSSI-CB was designed to be run with climate, population, and land use change scenarios to examine the interactions between water, carbon gain and biodiversity change across the 2,100 USGS 8 digit USGS Hydrologic Unit Code watersheds that span the lower 48 US. Results from this model using historic climate and landuse data indicated that the greatest increases in water use conservation may be made through improved irrigation practices, that manipulations in forest cover (i.e., massive harvesting) are an impractical way of increasing water supply, and the that the southeastern US has the highest potential for forest carbon sequestration. Biodiversity was calculated under steady state, historic conditions, with the greatest and mammal biodiversity occurring the southern US. The impact of future climate and population change were not included in this paper due to space limitations, but will be presented at the conference.

The Oklahoma Water Resources Board (OWRB) has initiated a major update of the Oklahoma Comprehensive Water Plan (OCWP) through a unique federal/state partnership with the United States Army Corps of Engineers (USACE). Scheduled for completion in 2012, the OCWP is assessing the physical and legal availability of Oklahoma's surface and groundwater resources, all in the context of water quality and infrastructure constraints, to meet the state's needs through 2060. The forecasted demands are being compared to physically and legally available supplies using the Oklahoma H₂O tool, a first-of-its-kind analysis tool that interactively assesses the potential for future water shortages on both a statewide and watershed level. Using a customized Microsoft Access interface, together with geographic information systems (GIS), the Oklahoma H₂O tool provides unprecedented analysis power in evaluating potential future "what-if" scenarios and potential solutions for meeting the state's water needs for the next 50 years. It has been used to quickly test alternative solutions brought forth through the OCWP's public input process and serves as the foundation for regional supply assessments and basin-level water plans. By adopting a continuous planning process, Oklahoma is adaptively managing its water resources on a basin-by-basin level. This process provides for careful consideration of anticipated future conditions while mitigating against the uncertainties in supply and demand that climate change, land use practices, and other future influences will bring.

Climate change is affecting the way engineers think about existing water supply infrastructure and the design of future infrastructure. Water supply planning is often based on historic patterns in weather and precipitation. However, changes in the climate may alter these weather patterns, including precipitation in the form of snow. Regions of the world dependent on snow for water supplies are likely to experience changes to the timing and quantity of runoff. Understanding these anticipated changes to future snowpack and resulting snowmelt runoff can influence how water resource engineers approach planning, design, and management of water supplies. Projections in climate change are expected to have varying impacts for different regions of the world, where no two locations are expected to experience the same fluctuations. New Zealand and Colorado are locations selected for technical comparison in this paper to illustrate (1) how different regions of the world are approaching and incorporating the commonality of potential climate change, (2) water supply from snow dominated catchments, 3) the availability of data and resources, and (4) a National Science Foundation-sponsored Eastern Asian and Pacific Study Institute exchange opportunity was undertaken by the first author to conduct research in New Zealand.

In many agronomic settings, irrigation is the only plausible system to sustain a dependable and economically viable agriculture. That is the case of semi-arid and Mediterranean basins such as the Limarí basin in Chile. In this basin a complex reservoir and irrigation system helps sustain more than 40,000 has of cultivated land with less than 150 mm of average annual precipitation. The very existence of this infrastructure, combined with favorable solar radiation fluxes throughout the year, causes water demand for irrigated agriculture to grow steadily. Upstream from the reservoir system there are 9,000 has of irrigated land that benefits indirectly from the built infrastructure (by using all available water during hydrologically average years). However, the lack of storage capacity makes these higher lands very sensitive to the significant climate variability, characteristic of the region. On the other hand climate change scenarios for this basin project a strong decline in available streamflow and a change in seasonality towards a higher relative proportion of water in winter months relative to summer months (when water is most needed). In this work we present a method to estimate climate impacts and a vulnerability assessment for a semi-arid snowmelt dominated basin and a method to test the value of irrigation policies as an adaptation strategy. Examples of these policies are related to new infrastructure that helps reduce the impacts of climate variability and seasonality changes as well as policies designed towards expanding the amount of land under irrigation.

The embodied water in globally traded goods is an increasing share of water consumption. An application of linear programming is presented to optimize Germany's crop production and trade. The 47 primary crops considered account for 38% of the world's total crop water use (1997–2001). Germany's baseline (1997–2001 average) production of primary crops resulted in the use of 41.5 Gm³/yr domestic freshwater and 9.6 Mha/yr of domestic land; of this, 19% of water and 18% of land were used for exports. From imports, there was an 18% water and 23% land dependency on foreign nations. For Germany to be self-sufficient (producing all primary crops domestically) it would require 11.19 Mha/yr (∼95% of total arable land) and 47.7 Gm³/yr water (∼15% increase from baseline). The minimum water footprint for German consumption of primary crops is 46.3 Gm³/yr; resulting in a 16% water dependency on imports at a cost of $1.53 billion/yr.

With regards to the impacts of climate change on water resources, snowmelt dominated basins have been recognized as one of the most vulnerable regions throughout the world. The main reasons are that these basins are prone to be affected by both temperature and precipitation changes. The Metropolitan Region in Chile is located in one of these basins, the Maipo basin. This Region holds more than 40% of the population of the country and a comparable number in terms of contribution to the country's Gross Domestic Product (GDP). Projections of future climate conditions present a dire future for this basin. Precipitation levels are projected to decrease by around 20% by mid 21st century and temperature levels in the mountains are expected to increase by around 3–4 °C (DGF-CONAMA, 2007). These changes affect the Maipo river discharges, decreasing its magnitudes and even affecting its seasonality. These new hydroclimatologic conditions would affect the supply of water for both the residential and industrial sectors in the Region. Because this sector has the highest priority and water must be secured, utility companies use a very high exceedance probability (98%) for its operation. This paper shows how climate change impacts on the hydrological regime of the Maipo river have a direct economic impact on the cost of operation of the utility companies and thus has a negative effect on the consumer surplus of both residential and industrial water users. The economic impacts assessment is carried out by first establishing the change in hydrologic conditions in the natural water supplies in the basin and then relating these changes with changes in economic conditions by two of the main sectors using the water in the basin modeling their current and future probability density functions. We used a water market transaction methodology to determine these economic impacts.

Nonpoint source (diffuse) pollution from stormwater runoff, failing septic tanks, and other diverse sources is a significant, and often dominant, cause of noncompliance with bacteria water quality standards in large watersheds throughout the United States. However, regulatory emphasis and economic resources have traditionally been directed primarily at reducing conventional point source pollution (e.g., wastewater discharges and combined sewer overflows) with little more than a casual understanding of the nonpoint source pollution sources within a large watershed. This work shows that quantification of nonpoint sources (including urban stormwater) and their influence on regulatory compliance should be at the forefront of watershed management efforts, not as a replacement for point source abatement, but as a factor worthy of equivalent scientific and economic attention. By comparing the value of dollars spent on point source abatement and nonpoint source abatement, as measured by improvements in receiving water quality or designated use attainability, this study shows that greater environmental value is possible by redirecting attention and dollars toward nonpoint source abatement. The work uses the Merrimack River Basin in New England as a case study, funded by the United States Army Corps of Engineers. The basin's 5,000 square mile size, interstate coverage, and mixed land use ranging from large tracts of forested areas to densely populated urban cities render it an ideal representation of dozens of large watersheds throughout the country. Watershed hydrology and mainstem hydraulics were characterized in detail using calibrated simulation models, which established a necessary and credible platform for evaluating dynamic water quality. Upon this platform, alternative management plans were formulated to blend point and nonpoint source abatement in various degrees. The outcome clearly illustrates how abatement costs and resulting effects on instream water quality for both point and nonpoint source controls must be clearly understood and managed together if the fundamental precepts and objectives of the Clean Water Act are to be addressed efficiently and cost-effectively. In fact, after a certain point, dollars spent on nonpoint source abatement in the subject watershed are shown to return more than four times the benefit of continued expenditures on point source abatement, which are currently mandated.

Turkey, as a rapidly developing and industrializing country, is in need of inexpensive, reliable, domestic, as well as sustainable and environmentally friendly energy sources. High potential of geothermal energy in Turkey motivates decision makers and local authorities to make investments on geothermal energy. Contingent Valuation Method (CVM) is the most widely used non-market valuation technique to value benefits of water resources projects such as thermal water resources. The idea of CVM is simple: "if you want to know the value place on something: Just ask them". CVM ask people how much are they willing to pay to keep a benefit. In this study, CVM is applied to Yozgat Province in Turkey to estimate to people's willingness to pay for geothermal energy instead of foil fuels for the heating purposes. Yozgat Province which has a population of 485,000 is located in the central Turkey and shared by Kızılırmak and Yeşilırmak Watersheds. The geothermal potential of Yozgat Province is estimated to be used for the population of 100,000 people. The results of CVM help decision makers to understand the underlying motivation to use geothermal energy. Moreover, valuation of tangible benefits like health benefits because of reduced air pollution can be used in to Benefit Cost analyses to be used in the decision making process.

The worldwide increasing demand for renewable energy sources will reflect on bio fuels' production. Increase in production of bio fuels will have important consequences to the environment, especially water resources, such as increased water demands, waste production, pollution and other externalities. To mitigate these impacts, the production of irrigated bio fuel crops must be adequately planned, considering the watershed's hydrology and water availability, existing infrastructure and competing water demands, including economic ones. This paper discusses a framework to investigate water management and operational decisions being raised as the demand for biofuels increases, and presents a modeling framework designed to study the effects of irrigated agricultural production, including bio fuel crops, in the water's economic value. The model uses a network based, economically driven optimization approach with surface reservoir operation. The objective function minimizes the water's scarcity cost to users, subject to physical and legal constraints in the system. The information produced should be useful to (a) support the water allocation among economic demands, especially the ones related to bio fuel crops production, (b) support the development and adaptation of water planning and management in watersheds where the production of bio fuels is expected to increase, (c) understand the impact of bio fuel production in the water's availability and economic value and (d) evaluate economic costs of meeting environmental demands in a scenario with high water consumption for bio fuel production.

Many developing communities have prepared watershed management plans and are looking for ways to meet stormwater regulatory requirements through the use of sustainable practices that also allow them to protect the environment and reduce their ecological footprint. However, while solutions to address watershed and stormwater problems are rather clear, paying for those solutions is proving to be a little murky. This paper describes the watershed needs and regulatory requirements that are making the implementation of funding alternatives critical. A summary of several funding alternatives (e.g., grants, bonds, fees, taxes, private incentives, and surcharges) available to local governments is provided as well as summaries of benefits, concerns, applicability, and implementation issues for some of the most common funding alternatives. The paper also presents the implementation steps (e.g., feasibility studies, outreach strategy, and implementation strategy) typically used for the development of a stormwater utility—a dedicated funding source. In addition, this paper presents lessons learned on implementation of funding alternatives based on case studies.

This paper presents the River Simulation and Optimization Coupled Model (RSOCM) for the optimal operation of regulated river systems in real-time conditions. This model couples a highly robust and numerically efficient hydraulic routing approach with the well-known multi-objective Non-dominated Sorting Genetic Algorithm II (NSGA-II). The proposed model overcomes the lack of robustness of current models for unsteady flow routing. The lack of robustness of current unsteady flow models (e.g., numerical instability) constitutes a strong limitation for the development and implementation of real-time strategies in complex hydraulic systems that are intended to fulfill multiple objectives (e.g., minimization of flooding, optimal water allocation at specified diversion points). The real-time control of such complex systems may require thousands of computations of hydraulic routing for each operation interval. The optimization objectives supported by the RSOCM model include the optimal water allocation at specified diversion points and minimization of flooding. To demonstrate the proof of concept of the RSOCM model, it was applied to a hypothetical river system. As frame of comparison for the RSOCM model, the MODSIM-DSS model (Colorado State University, 1995) was used in this paper. The results suggest that the RSOCM model is a robust tool that can be potentially used for the optimal operation of multi-objective regulated river systems in real-time conditions.

This paper describes the simulation of soil erosion and sediment yield from agricultural watershed using remotely sensed data and data base management tools like Geographical Information System (GIS). Finite Element Method (FEM) technique has been used for solving the governing partial differential equations. The GIS has been used to generate the finite element grid map, slope, DEM, Landuse (LU)/Land cover (LC) and Soil map. The diffusion wave based soil erosion and sediment yield model for overland flow and channel flow has been developed and applied to the Khadakohol and Harsul watersheds located in Nashik district of Maharastra state, India. Soil map is prepared based on ground truth information and the major soil type is sandy silt loam. Scanned topographical maps of 1:25,000 scale are registered in ERDAS IMAGINE version 9.1 image processing software. Watershed boundary, drainage and contours are digitized in ArcMap. DEM has been prepared based on contours and slope map has been generated from the DEM by using the slope option of Spatial Analyst in ArcMap. Remotely sensed data of IRS 1D LISS III with resolution of 23.5m has been used to extract LU/LC map of Khadakohol and Harsul watersheds. Input files of slope, Manning's roughness, Crop management factor and Erodibility factor have been prepared. Part of the available data has been used for model calibration and the other part for model validation. The developed model has predicted satisfactory results for both calibration as well as validation events, when compared with the observed data.

For over two decades, the U.S. Army Corps of Engineers has required that all of their planning processes address the Nation's water resources needs in a systems context. Corps policy requires that all flood risk management studies adopt risk analysis. Although the Corps has a requirement for systems approaches using risk analysis, there is little guidance and few tools to support these requirements. For this reason, the Corps' Institute for Water Resources sponsored investigations into the development of a new application to analyze complex riverine systems while implementing the flood risk analysis and systems requirements. This new application, currently called HEC- FRM (Flood Risk Management), will eventually become the next generation of the Hydrologic Engineering Center's Flood Damage Analysis (HEC-FDA) model. It will include a systems approach, event-based sampling, the ability to do scenario analysis, and structure-by-structure, cost, non-structural, loss-of-life, and agricultural damage analyses. The tool will accommodate many, if not all, of the recommendations that the Corps concurred with from the National Research Council report on the Corps' implementation of risk analysis for flood damage reduction (NRC, 2000), and it will also aide in implementing the Chief of Engineers' Actions for Change. This presentation will introduce the modeling concepts including sampling and solution techniques, uncertainty definitions, and system component fragility and performance interactions/relationships.

This project examines the flooding dynamics along the Muskingum River near the city of Zanesville, Ohio. Simulating various peak flood events using a hydrodynamic model will provide Muskingum County engineers with valuable information regarding inundated areas, extent, and effect on local communities for different flood events. The impact of various Muskingum River flood events, including the 100 year flood, on the urban environment in Zanesville, Ohio is studied. The project provides a useful hydraulic modeling framework that produces urban flooding maps for the city of Zanesville. These maps show how water surface elevations and water depths vary spatially and temporally, and provide a more detailed picture of how flood waves move in urban environments. A hydrodynamic model called LISFLOOD-FP is used to simulate river flow and flooding. LISFLOOD-FP is a finite-difference flood inundation model that can accurately model ID channel flow along with 2D floodplain flow. LISFLOOD-FP is a well established hydrodynamic model that has been proven to properly simulate flood inundation for fluvial, coastal, and urban events. Modeling efforts demonstrate that better knowledge of discharge on the Muskingum River provides a valuable insight into how floods travel through the floodplain. Model simulations of the most profound natural disaster in Ohio history, the Flood of 1913, and a typical peak 2 year flood have been completed as first runs. Preliminary results gave discharges that closely match those estimated by the United States Geological Survey, and the variation of output discharge with time have shown to approximately fit the shape and amplitude of those estimated for the 1913 Flood and those measured for the peak 2 year flood. The Flood of 1913 was greater than the peak 500 year flood over most of the Muskingum watershed, and resulted in hundreds of lost lives statewide and a hundred million dollars in property damage. The importance of such an event to river communities lies in the understanding and awareness of how peak floods occur and travel, especially in urban environments. From this, steps towards flood control and damage prevention can be made. The fully parameterized Muskingum River model allows us to (1) produce urban flooding maps for Zanesville, (2) build a framework for sensitivity studies on impacts from urbanization and climate change, and (3) predict inundation throughout Zanesville, a city of 25,000 people.

Three chevrons (U-shaped river training structures) were constructed in early 2008 in the St. Louis Harbor to improve the navigation channel and enhance environmental diversity. Post-construction surveys have shown the chevrons have created improved depth for fleeting along the Missouri shore and a deeper navigation channel along the Illinois shore. However, local professors of geology and planetary science have garnered much publicity by stating that the chevrons are "a loaded gun pointed at the levees protecting the Illinois floodplain" and raise flood levels significantly. Navigation works have not been found to have an effect on flood levels. The St. Louis District (SLD) will demonstrate that the chevrons have no impact on water levels in three ways: physical measurements of channel cross sections, comparison of stages at upstream and downstream locations for pre- and post chevron conditions, and by two- dimensional hydrodynamic modeling. Cross sectional area has increased by several thousand square feet following chevron construction. Gage stage comparisons show no significant difference in upstream stages for pre- and post- chevron construction. Although the 2D hydrodynamic modeling is not yet completed, it is expected that the simulation will also show that there is no significant impact on water levels.

Anthropogenic land uses generally diminish biological integrity and interconnectivity of rivers, lakes, perennial and intermittent streams, and wetlands. Areas offering distinctly different physical and biological conditions become isolated, preventing many species from successfully utilizing remnant, high-quality, life-cycle-requisite habitat. This project identifes and restores full life-cycle access to naturally occurring refuge, spawning, and feeding habitat. Native potadramous fish species were the measure of habitat desirability and accessibility. Habitat ingress and egress were equally considered. Remedial work was supported by the NOAA, funded through the ARRA, and was carried out by a unique alliance of government agencies, non-profit organizations, volunteer and community service groups, and private industry. When completed in late 2010, the project will reconnect the Milwaukee River Estuary and nearshore waters of Lake Michigan to over 150 additional miles of rivers and major tributary streams, dozens of smaller streams, and 119,000 acres of watershed including over 14,000 acres of wetlands.

This paper discusses the development and application of a simplified method to compare the relative habitat output expected from various side channel restoration alternatives. The analysis compared various side-channel alternatives characterized by either a seasonal or perennial flow condition. The channel alternatives included a trapezoidal rock channel, a rock channel with wood debris benches, a trapezoidal section with bio-engineered banks, and bio-engineered configurations with either 3 ft or 5 ft (0.9 m or 1.5 m) high "benches" at the bank toe. Though not critical to habitat outcomes, project alternatives also considered long-span, short-span, and at-grade side rock weir channel crossings. For this evaluation, potential habitat value was measured by estimating effective habitat units (EHU), which were a function of habitat area, inundation probability, and habitat quality.

This paper discusses the design of a marsh restoration at Juanita Beach Park in Kirkland, Washington. The marsh attempts to recreate lakeside habitat and hydrologic function that has become relatively rare in contemporary times. The marsh design presented many challenges, primarily associated with the depositional environment near the mouth of Juanita Creek and a reversed hydrologic regime on Lake Washington. The project team developed a diversion weir design featuring a slot with stop logs. With the stop logs in place, the weir slot excludes higher wintertime flows and accompanying sediment from the marsh; with the stop logs removed during the spring and summer, the weir slot will facilitate fish passage and feed lower flows into the marsh. The low-profile overflow weir maintains floodplain hydraulic function during extreme events. The design team also developed an operation plan that attempts to minimize potential sediment delivery to the marsh, while maximizing the opportunity for fish passage.

The McDowell Creek watershed drains directly into the primary drinking water supply reservoir for the Charlotte-Mecklenburg area. The watershed, which is approximately 29 square miles in area with 93 miles of streams, has experienced rapid development in recent years. Sediment from construction sites and bank erosion has destroyed aquatic habitat in McDowell Creek, prompting the North Carolina Division of Water Quality (NCDWQ) to label McDowell Creek as biologically impaired. Charlotte-Mecklenburg Storm Water Services (CMSWS) is targeting this watershed and has begun work on numerous projects to improve the water quality and restore the eroded stream channels of McDowell Creek and its tributaries. CMSWS initiated a watershed-wide strategy consisting of a combination of regulatory measures, land acquisition/preservation, and development of a comprehensive watershed management plan to address water quality issues in this sensitive watershed. Baker has completed a two-phase project to conduct a detailed assessment of the streams within the watershed, as part of the comprehensive watershed management plan. The goal of the assessment was to document riparian conditions and to prioritize riparian management needs within the watershed. This data was used by CMSWS within the McDowell Creek Watershed Management Plan. This paper will review the innovative watershed-scale approach taken by CMSWS to reduce sediment loading to the drinking water supply.

The development of phased Watershed Restoration Plans (WRPs) represents the next step in the implementation of a truly science-based watershed improvement effort for the Menomonee and Kinnickinnic River watersheds. The primary purpose of the WRPs was to identify specific actions that can be implemented between 2010 and 2015 to improve water quality and habitat within the two watersheds and present general recommendations for activity beyond 2015. The identified actions focus on public health/bacteria, habitat and aesthetics, and phosphorus. Although achieving the established goals will result in significant projected pollutant load reductions and improvements to habitat, all water quality standards as they existed in 2009 are not anticipated to be met under all circumstances in the watersheds. This paper will describe the development of the WRPs, the major components and how the adaptive management process will be used to work towards the goal of improved water quality and habitat within the Menomonee and Kinnickinnic River watersheds.

The City of Appleton, Wisconsin has designed the relocation of a portion of Apple Creek North, located in the northern portion of the City. In conjunction with this design project, the floodplain in the Apple Creek Subwatershed is being remodeled to account for upstream storage and development changes that have occurred within the subwatershed. In 1999 a Floodplain analysis was performed to determine the extent of the Floodplain of the Apple Creek corridor. This floodplain was approved by WDNR, but was never formally approved by FEMA. In 2007 ACEOM conducted the Apple Creek Subwatershed Leverage Floodplain Mapping Study. Since the 1999 floodplain analysis was completed, the Subwatershed has experienced rapid development, and therefore, changes in stormwater discharges have occurred. Urbanized areas prior to 2004 have no detention unless they are tributary to Holland Pond (a regional on-line stormwater detention pond). Development within the City that has occurred since 2004 was required to follow the City Stormwater Ordinance and meet a requirement to reduce peak flow to presettlement conditions. A hydrologic model was created to determine the peak flow changes due to the changes in land use, detention facilities, and flow routing. A hydraulic model was created initially using the data from the 1999 hydraulic model, and then updated using additional field survey information that was gathered in areas where changes have occurred. Once all of the information was gathered and internally quality checked, a floodplain and floodway was created and submitted to WDNR. The WDNR approved the floodplain and used the elevations for the remapping of the Apple Creek Subwatershed as part of the statewide Digital Flood Insurance Rate Map (DFIRM) update process. The City of Appleton has prepared a CLOMR for the Apple Creek Subwatershed. The CLOMR includes the Apple Creek North relocation project, and additional upstream detention that was constructed since the 2007 floodplain analysis was completed. The Apple Creek North relocation project consists of channel naturalization and floodplain lowering project for a portion of Apple Creek North. The design included naturalizing approximately 4500 feet of channel and relocating the channel to the north. Design constraints involved the future development of adjacent lands, future widening of County Highway to south, expansion of existing waterway crossings, constructability of access to site, and earth work balancing. The goals of the project included the relocating the channel to allow for roadway expansion and to change the floodplain limits (through reduction of the floodplain elevation) to allow the adjacent lands to be removed from the floodplain (once a LOMR was issued). The flow splits were analyzed along Apple Creek North to determine floodplain effects of routing additional flow south towards the main branch of Apple Creek. Four waterway crossings are being designed to convey the 100-year flood flows. The channel naturalization and waterway crossing improvements reduced floodplain elevations from one to two feet within the project corridor and have water surface elevation reductions further downstream.

Portions of the 700 km² Elm Creek watershed in southern Minnesota have undergone watershed and channel improvements over the past decade to mitigate turbidity and biota impairment. Increased row cropping, artificial drainage, channel modifications and precipitation have cumulatively contributed to impairment and channel instability. Uplands that were once a prairie pothole landscape are now predominately drained corn-soybean fields, providing little hydrologic storage and sediment attenuation during peak runoff. Riparian degradation and channel discontinuity characterize much of lower Elm Creek. Wetlands have been restored in the upper watershed to reduce runoff and nutrient loading from croplands. Downstream, a 750 meter riparian corridor of Elm Creek was restored and the channel improved by oxbow reconnection, bluff and streambank protection. Monitoring will document erosion and sediment deposition within the reach and Index of Biotic Integrity (IBI) data will be collected to characterize fish and invertebrate communities in the stream.

Jamaica Bay, located within the Boroughs of Brooklyn and Queens, New York City, covers 67.3 square kilometers and opens into the Atlantic Ocean via Rockaway Inlet. In the early 1900's, Jamaica Bay was an extensive estuarine ecosystem that sustained large expanses of salt marsh. Over the last century, urban and industrial development has modified the natural environment surrounding the marsh islands through activities such as dredging and filling, construction, pollution, and over-harvesting or eradication of native plant and animal species. Based on aerial photography interpretation of Jamaica Bay, the New York State Department of Conservation (NYSDEC), estimated that approximately 567 hectares of tidal salt marsh have been lost since 1924, with the rate of loss rapidly increasing in recent years. At Elders Point between 1994 and 1999 an estimated 89 hectares of salt marsh were lost at a rate of 17.8 hectares per year. It is estimated that if this trend continues, all remaining salt marsh within Jamaica Bay may be lost over the next three decades. Our work involves a multi-agency group led by the U. S. Army Corps of Engineers (USACE) to restore the tidal wetlands of Elders Point East and consists of the placement of fill, regrading the site to appropriate elevations for the target community, and planting with native coastal plant species. This design was based on the approximate extent of the 1974 marsh coverage as reported by NYSDEC. Restoration efforts have included extensive monitoring to ensure worthwhile ecological goals have been provided and are a long term sustainable benefit to Jamaica Bay. Challenges that need to be overcome include compaction, subsidence, and erosion of placed material. Additionally, accretion of material and plant survival will require monitoring. The sustainability and plant survival will be an ongoing challenge with physical, chemical, and biological stresses present in the bay. Monitoring data to date have indicated that the project has provided much of the anticipated benefits with minimal erosion or deposition of sediment and Spartina alterniflora has exhibited a growth rate consistent with the control marsh at JoCo. The sustainability of Elders Point East will have important implications regarding future salt marsh restoration efforts (e.g., Elders Point West) and likely serve as a benchmark for similar projects.

Re-establishment of floodplain hydraulic function is increasingly a goal of restoration programs, yet the approximate magnitude of possible change to attenuation due to reach-scale restoration remains poorly quantified. The efficacy of channel restoration on flood attenuation was examined using restored reaches and synthetic reaches representing median dimensions of channel restoration projects in North Carolina (e.g. ∼ 1 km in length). An industry standard dynamic flood routing model (UNET in HEC-RAS) was utilized to route floods in impaired and restored reach models. Our study showed that the predominantly small scale of current channel restoration will provide minimally quantifiable enhancement to flood attenuation. Sensitivity analysis demonstrated that attenuation of peak discharge is overall most sensitive to channel and valley slope, channel and floodplain roughness, and channel and valley length in decreasing order, but is dependent on flood magnitude. Floods of intermediate magnitude (between 2 and 50 yr return interval) were impacted most by restoration.

By many accounts, the upper Mattole River has experienced significantly lower summer low-flow over the last 10 years (Klein 2004). This has created a condition where upper reaches of the river that formerly provided valuable cold-water rearing habitat for juvenile salmonids have been significantly impaired by the lack of flow (Downie, et al., 2002). Because the upper portions of the river channel are dominated by bedrock, it is unlikely that channel aggradation or increased subsurface flow has contributed to the observed low-flow condition in the upper basin. Nor does annual precipitation appear to have decreased significantly during this period (Klein 2004). Thus forcing two questions. Where has the water gone, given that total annual precipitation amounts have not changed significantly? And, what, if anything can be done to increase late dry-season base flow? Land use changes that have occurred over the past century have probably exacerbated low-flow conditions, including increased diversion of surface water, increased evaporation from manmade ponds, compaction of soils from logging and ranching activities, construction of impervious surfaces, draining of wetlands, and construction of roads. However, the majority of these changes occurred several decades ago, and thus, are probably not primarily responsible for the significant reductions in low-flow observed since 2000. Widespread timber harvest resulted in a vast network of logging roads, significant erosion, and compaction of surface soils, but most of this activity occurred from the 1950s until the 1970s. Although there has been some additional residential development in the watershed, there are no diversions in upper portions of the watershed and reductions in flow are observed even there. This leaves increased evapotranspiration by the forest and a changed climate regime as probable causes for the recent decreases in flow. Both altered forest stand composition and climate change have some degree of anthropogenic causation and, as with many other river systems, it seems likely that cumulative anthropogenic changes to the watershed are the primary cause for impaired water quality and degraded aquatic habitat. This project was undertaken to help determine if hydraulic modifications in the upper watershed could potentially increase the late summer base flow to help mitigate the observed drying up of this watershed.

Restoration of fish passage along our rivers and streams can improve the overall aquatic habitat and environmental conditions of our waterways by allowing migration and spawning of species currently blocked by dams. Fish passage can enhance the overall productivity of ecosystems by enabling anadromous fish to return to their previous spawning grounds. This, in turn, increases the system's food supply web for resident and migratory fish. Perhaps the most effective method of restoring fish passage is to remove the stream impediment and restore the channel to natural conditions. However, existing conditions such as the historical and cultural aspects of the dam, the chemical composition of built-up sediment behind the dam, and the potential for increased downstream flood hazard risk may influence the selection of a recommended plan. Restoring environmental balance to our nation's rivers may affect historic structures and archaeological sites. This can trigger state and federal historic preservation laws, and interest in preserving a piece of local history, as well as providing an opportunity for historic discovery (McClain, et al., 2008). So, how do you determine the best method of restoring fish passage for your project? Congress passed the National Environmental Policy Act (NEPA), Public Law (P.L.) 91–190 in 1970 to establish a national policy for the protection and maintenance of the environment. The law provided a process all federal agencies must follow in evaluating the potential impacts a project has on the environment. Following the NEPA process leads to the publication of an Environmental Assessment which contains a compilation of available data regarding the project, including public comments, that allows decision makers to make educated and informed decisions. This paper addresses the National Environmental Policy Act (NEPA) and how it served as the decision document in determining the best alternative to restore fish passage at the Woodland Dam. Specifically, the paper will address environmental considerations typical of urban streams and the historical considerations associated with modifying a dam originally constructed in the 1640's. Emphasis will be placed on the interagency coordination between the U.S. Army Corps of Engineers (Corps), the Pennsylvania Department of Environmental Protection (PaDEP) and the Pennsylvania Historical & Museum Commission (PHMC). We will focus on how issues are resolved concerning environmental benefits and impacts balanced against maintaining our historical and cultural resources.

The Missouri River Ecosystem Restoration Plan/EIS (MRERP/EIS) is among the largest basin-wide restoration planning efforts in the US, and represents an unparalleled opportunity and challenge. The aim of the effort is to identify restoration, mitigation and recovery goals for the Missouri River and its tributaries, ecological systems and native species for the coming 30–50 years. The complexity of the project and its geographic scale present numerous challenges, among which is the need to provide real engagement opportunities for the interested public and stakeholders, including members of 29 basin tribes, 8 states and dozens of federal, state and local agencies. To address this challenge, a team of planners representing multiple backgrounds and approaches has developed the MRERP roadmap, which incorporates tested and innovative techniques to ensure procedural and legal requirements are met through a transparent, objective, and scientifically based planning approach. The roadmap integrates NEPA principles and practices, the USACE 6-Step Planning Process, the Open Standards for the Practice of Conservation, and the lessons and best practices of previous large-scale ecosystem restoration planning efforts.

In 2008, the State of Michigan enacted legislation requiring that new or increased high-capacity withdrawals (greater than 100,000 gallons per day) from either surface water or groundwater be reviewed to prevent Adverse Resource Impacts (ARI). Science- based guidance was sought in defining how groundwater or surface-water withdrawals affect streamflow and in quantifying the relation between reduced streamflow and changes in stream ecology. The implementation of the legislation led to a risk-based system based on a gradient of risk, ecological response curves, and estimation of groundwater-surface water interaction. All Michigan streams are included in the legislation, and, accordingly, all Michigan streams were classified into management types defined by size of watershed, stream-water temperature, and predicted fish assemblages. Different streamflow removal percentages define risk-based thresholds allowed for each type. These removal percentages were informed by ecological response curves of characteristic fish populations and finalized through a legislative workgroup process. The assessment process includes an on-line screening tool that may be used to evaluate new or increased withdrawals against the risk-based zones and allows withdrawals that are not likely to cause an ARI to proceed to water-use registration. The system is designed to consider cumulative impacts of high-capacity withdrawals and to promote user involvement in water resource management by the establishment of water-user committees as cumulative withdrawals indicate greater potential for ARI in the watershed.

The Calumet Area, formerly the center of the industrial boom in the mid 1800's, is now home to a large diversity of plants and animal life that includes endangered species, over 200 species of birds, and one of the most ecologically significant complexes of wetlands in the Midwest. Development and industrializations contributed to pollution and degradation of the area. The City of Chicago and various stakeholders are developing ecosystem restoration plans for the Calumet watershed that preserve, improve, and create habitat, especially on areas with endangered threatened species such as the black-crowned night heron and yellow-headed blackbird. These birds nest in the wetlands of Hegewisch Marsh and Indian Ridge Marsh where high water levels flood their nests and low water levels put them at risk of predators. The ecological restoration of Hegewisch Marsh and Indian Ridge Marsh includes interconnecting and restoring wetlands, managing water levels with control structures, improving or enhancing current habitat, removing debris, and shoring restoration. Managing water levels in the Calumet Area at Hegewisch Marsh and Indian Ridge Marsh is of great priority to meet the goals of the ecosystem restoration of the area.

The Mississippi River is one of the world's great rivers and is the only river in the United States to be formally recognized by Congress as both a nationally significant ecosystem and commercial navigation system. The river has a long and colorful history and has played a significant role in shaping the region's social and economic development. However, the Mississippi River is not a single homogeneous unit. From its source in northern Minnesota to the Gulf of Mexico one can identify at least five distinct Mississippi Rivers based on geomorphology and hydraulics. Concomitant with these differences in the river are variations in navigation and flood risk management that result in divergent river management strategies. Levees, reservoirs, floodways, pools and locks are some of the different structures that are in place on various reaches of the river to address the concerns of flood risk management and navigation. The effects of river regulation, floodplain development and watershed modifications present constant challenges to ecosystem rehabilitation along the Mississippi River. Consequently, floodplain and wetland restoration must be developed within the context of the potentially different directions that navigation and flood management have taken the river. Because the Mississippi system varies widely in hydraulics and hydrology from source to the Gulf, ecosystem rehabilitation likewise takes different forms in different regions along the river. Moreover, the goals, targets and metrics of river rehabilitation are not constant across the entire river system.

The effects of the urbanization on Poyang Lake wetland are studied based on the groundwater fluctuation, development of the city, surface runoff, and weather conditions surrounding the lake. Through the simulation of the effects of the urbanization cover area on the wetland the surface runoff and groundwater model is presented to discuss surface flow and groundwater computation. The net water quantity of the wetland surrounding the lake is analyzed according to the water budget method. Through hydrologic budget, the drought and degradation of the wetland due to the development of the cities surrounding the lake is predicted and the relative treatment plan is correspondingly described in the paper.

The City of Bellingham, Washington (2008 population, 76,130) constructed a diversion dam and tunnel project on the Middle Fork of the Nooksack River in the early 1960's to divert supplemental water into Lake Whatcom, the City's primary municipal source of water supply. The City is located on Puget Sound, about 90 miles north of Seattle, and 21 miles south of the U.S. — Canada border. See below Figure 1, Project Vicinity map. The diversion dam is located in a steep and narrow gorge on the Middle Fork Nooksack River on the heavily forested western slopes of Mt Baker in northwestern Washington, about 20 miles south of the U.S. — Canada border. The diversion dam site is characterized by steep forested slopes, a boulder and cobble streambed with numerous bedrock outcrops, and a steep pool and cascade channel morphology. The Middle Fork Nooksack River Diversion Dam is shown in Figure 2. When the diversion dam was constructed in 1960-61, there was little awareness in the community of either fish passage issues or the looming decline in Pacific Northwest salmonid stocks. Therefore, no fish passage provisions were included in the design of the 30 foot tall by 150 foot long concrete dam. Completion of the dam and diversion tunnel in 1961 therefore cut off approximately 9 miles of potential salmon habitat river channel. Although there are no definitive written records of salmon being present in the upper Middle Fork Nooksack watershed prior to completion of the dam, anecdotal information from Native American oral sources indicate that anadromous fish were present in the upper watershed before European settlement began in the area in the 1850's, and fisheries biologists generally believe that salmon could survive in the upper reaches of the Middle Fork of the Nooksack River if they could somehow get past the passage barrier created by the diversion dam. By the beginning of the 21^st Century, the dam and diversion gate structure were starting to show the effects of the ravages of time from the cumulative effects of more than 40 severe Washington Cascades winters, and the abrasive effects on the concrete dam spillway of the pulverized "rock flour" entrained in the river water derived from Mt Baker's alpine glaciers in the headwaters of the watershed. The need to repair and rehabilitate the facility was becoming readily apparent. By that time also, the prevailing public sentiment in this former timber, shipping, and fishing town, now reborn as a highly desirable cosmopolitan university town that was rapidly attracting new residents from throughout the Puget Sound region and beyond, had been transformed by the environmental movement. A strong community desire to remove this barrier to Salmon migration by either adding a fish ladder to the existing dam, or constructing a new diversion facility that would not require a diversion dam for its operation, had firmly taken root. The City Council made elimination of this barrier to fish passage a priority for the City, and City staff formed a partnership with two local Native American tribes, the Nooksack Indian Tribe, the Lummi Nation, and the Washington Department of Fish and Wildlife to search for a workable solution.

Recent expansion of the Indianapolis Airport and supporting interstate infrastructure resulted in the relocation of over two miles of the East Fork White Lick Creek (EFWLC) and North Creek (NC). Design of the relocated channels was conducted using natural channel design methodologies intended to improve the overall condition of the EFWLC and NC as compared to the pre-construction condition. The design of the channel relocation was based upon the inter-relationship of hydrology, hydraulics, and geomorphology. Because of anticipated development in the watershed associated with the relocation and expansion of the airport, design criteria for the relocated channels needed to address the existing hydrology and land use, as well as an anticipated hydrologic and hydraulic condition under future land use changes. Geomorphic, biological, chemical, and hydraulic conditions are being monitored to evaluate the success of the stream relocation for verification of compliance with the permit conditions. Five years after completion of construction, both channels continue to adjust to their watershed condition but appear to be stable overall. Each channel is experiencing an appropriate number of bankfull events annually. Available habitat and sampled biological communities show that the relocated channels are generally healthy and improving year to year. Most indices show the relocated channels to be in as-good or better condition than the pre-construction condition or the undisturbed portions of each channel immediately upstream of the relocation.

The restoration of stream flow variability in rivers regulated by dams is a key element to preservation of fish populations. Several species of tropical fish rely on periodical connection of the river with the floodplain during the wet season, which has been severely reduced in heavily impounded and regulated rivers. In order to recover part of the stream natural variability and allow the floodplain connection with the main river channel, reservoirs may be re-operated for artificial flooding. This paper presents the study of artificial flooding downstream of the Irapé Dam, in Brazil. Several peak flows were tested and the resulting floods were evaluated based on steady state river hydraulics. Results allow the location of the flooding areas downstream, which is important to identification of environmental protection areas, as well as the corresponding peak flows. The latter is critical to help identify artificial flood operations with reduced cost and impact to reservoir operation, especially when other competing uses, such as energy generation and water supply, are involved.

There have been many wetland mitigation and restoration projects completed over the years, but very few have as many unique aspects as this particular project or have been as complicated in terms of design, permitting and construction. Located in northeastern Illinois in western DuPage County, the West Branch Forest Preserve (WBFP) is a 811 acre preserve that contains several miles of walking paths, three fishing lakes that were once quarries and 1.6 miles of the West Branch DuPage River. The preserve is located in a well defined U-shaped valley formed during the last glacial period. The northern third of the preserve consists of the main parking area, river, the lakes, forest and some old fields. To the south are approximately 350 acres consisting of old agricultural field, floodplain forest, forest, wet prairie, scrub shrub and remnant fen habitats. Design of this project required the development of many unique and creative solutions to achieve project goals of wetland creation and restoration, habitat improvement and river restoration. Following input from various stakeholders the design contains the following elements: Over 350 acres restored to native habitat; of which approximately 140 acres of wetland created and enhanced, including rehydration of a 25 acre remnant hillside fen. The hydrologic restoration of the wetlands is driven by disabling the extensive field tile system and re-infiltration of surface water. Additionally the project includes the restoration of 6,000' of the West Branch DuPage River to raise the base flow elevation to re-access the historic flood plain, and nearly 100 acres of tree and brush removal (mainly buckthorn and other non-natives); and implementation of a 10 year management and monitoring program.

Underwood Creek extends eight miles upstream from its confluence with the Menomonee River, located near Milwaukee County Grounds (MCG), and is contained within in a highly urbanized watershed. Due to past flood management concerns, Underwood Creek has undergone considerable alteration that included floodplain filling, channel widening and realignment, and the installation of concrete lining along a significant portion of its length. These channel alterations have successfully reduced peak water surface elevations along Underwood Creek, but contributed to downstream flooding conditions. As a result, the Milwaukee Metropolitan Sewerage District (MMSD) initiated the MCG Floodwater Management Facility Project, which includes an overflow diversion structure on Underwood Creek and an approximately 900 acre-feet floodwater storage facility on MCG property. The MCG floodwater storage facility has provided an opportunity to rehabilitate approximately 6,600 feet of Underwood Creek watercourse through the removal of concrete channel lining; the development of a replacement bioengineered channel, with riffle and pool sequences; and the reactivation (lowering) and re-vegetation of the adjoining floodplain. The MMSD Underwood Creek Rehabilitation and Flood Management - Phase 1 Project addresses the design and construction of rehabilitation improvements along 2,200 feet of watercourse, and is scheduled for completion in mid-2010. Thirty years of stream flow gage records were evaluated to develop low-flow and bank full discharges, which served as a basis for the rehabilitated channel design. Bioengineered bank stabilization measures were developed that satisfy stability criteria immediately upon implementation, and will promote eventual establishment of dense streambank vegetation. An approximately 7 acre floodplain re-vegetation plan was created that contains wet meadow, shrub-carr, and floodplain forest wetland areas, which required design integration between the hydrologic and hydraulic watercourse analyses and the channel and floodplain grading plans. Backwater simulations for a wide range of design events were completed, providing assurance that the rehabilitated watercourse will function as intended over a variety of hydrologic conditions, given a highly urbanized watershed. Adopted rehabilitation goals included a desired increase in floral diversity as well as introduction of slope stability; provisions for shading of aquatic resources; methods to eradicate non-native species within the planting and seeding area and an abutting buffer zone; and perpetuation of Butler's gartersnake habitat.

Ensemble forecasts have a growing use in the field of water resources systems analysis. In general, two types can be used: rainfall/runoff models and stochastic techniques. But which is better? We compare forecasts for the Chattahoocee River in Georgia generated by NOAA's Southeast River Forecast Center using ESP and a stochastic technique developed by Robert M. Hirsch. Similarities and differences in the forecasts are shown and analyzed.

This paper summarizes an extensive review on the applicability of Artificial Neural Networks (ANNs) in urban hydraulics and hydrology. The identified areas for ANN application include rainfall — runoff — sewer flows, snowmelt — runoff-sewer flows, stormwater and Combined Sewer Overflow quality modeling, Total Loading Analysis, and Real Time Control. This paper also introduces the results of two recent ANN applications in City of Edmonton, Alberta, Canada. One is the early warning system for the Enhanced Preliminary Treatment (EPT) facility to treat the wet weather flow at the Goldbar wastewater treatment plant and the other is the prediction of Combined Sewer Overflow (CSO) based on monitored rainfall data.

Total maximum daily loads (TMDLs) for different water quality constituents were developed for many creeks, which are listed by United States Environmental Protection Agency (USEPA) 303(d) document. When available data for estimation of loads are uncertain, the TMDL decisions are also affected. To provide flexibilities for the decision maker, in this research, a fuzzy model based TMDL development was attempted. For examining the suitability of this proposed approach, a case study had been done with the available data for two watersheds namely Coffee creek and Salt Creek in the historic Indiana Dunes Region of North West Indiana.

Water utilities that rely on surface water supplies often experience variable production due to weather. Future drinking water supply for such systems is mathematically uncertain. However, system simulations using flow data can determine the probability of sufficient future supply in support of planning and management activities, such as evaluating expansion alternatives and developing water shortage plans. In the most direct form of these applications, historical source stream flows can be applied to operational models of system and policy alternatives, showing how those alternatives would have fared under historical hydrologic conditions. In many cases, however, the available historical data are insufficient to capture likely upcoming hydrologic conditions and their impacts on system and policy performance. Historical stream flow records are often too short to capture potential source variation in sufficient detail and/or may not reflect future hydrology due to climate oscillations or change. Resulting evaluations of system or policy alternatives may not adequately reflect true future performance and reliability. One remedy for addressing these historical data shortcomings is to construct statistical models of source stream flows that reflect longer-term climatic mechanisms, and then use stream flow simulations from those models in the place of historical source flow data when evaluating system and policy alternatives. Statistical models can be used simulate long stream flow series or generate multiple series depicting a range of possible flow outcomes, producing long-term and/or probabilistic characterizations of system and policy alternatives. When developing statistical models for these applications, special attention must be directed toward the time scales at which source flow variability impacts system performance and reliability. Surface water supply reliability is often impacted by hydrologic variability at multiple time scales, from instantaneous to inter-annual, depending on storage volumes, time bases of withdrawal permits and operations, and other factors. The time scales which are relevant to reliability can vary from system to system. During source flow model development, it is therefore important to understand the time scales of relevance to system reliability for the specific application, and then ensure that flow models engender flow statistics at those time scales that are plausible. For example, a surface water supply that depends on an inline reservoir with a residence time of 15 days would require a stream inflow model that represented daily- or weekly-scale source flow distributions and autocorrelations well. It may also be important for the source flow simulations to reflect longer-term variations, such as ENSO modality or systematic climate change, but any such simulations that did not also properly reflect daily statistics properly would not accurately depict critical short-term reliability issues among system alternatives. On the other hand, daily- or weekly-scale statistical fidelity may be less important if the reservoir had a residence time of, say, 150 days. To meet multi-scale modeling goals, it is often possible to develop and link multiple scale- specific models (or externally-generated simulation data) to produce final source flow simulations containing multiple-scale statistical fidelity. One such approach consists of sequential downscaling (Figure 1). Long-time-scale (e.g. interannual) models are used to engender longer-period hydrologic tendencies (e.g. ENSO, drought dynamics, climate change) in source flow or in rainfall that impacts source flow. Moderate-time-scale models are then developed to accept simulation inputs from long-time-scale models, producing moderate-scale (e.g. seasonal or monthly) simulations of source flow or rainfall that reflect moderate-scale statistics while respecting long-scale input conditions. If necessary, short-time-scale models are then developed to accept simulation inputs from moderate-time-scale models, producing short-scale (e.g. weekly or daily) simulations of source flow that reflect short-scale statistics while respecting long- and moderate-scale input conditions. This paper will describe a sequential downscaling procedure developed for Tampa Bay Water in Florida. Tampa Bay Water, along with Hazen and Sawyer, P.C., developed this procedure to support probabilistic analyses of its surface water supply system in a variety of projects.

A nonpoint-point source lumped-parameter pollutant loading model appropriate for prediction of average yearly loads on small suburban watersheds has been developed. Three numerical physical process models describing transport processes observed in such watersheds are included; a build up- wash off model, a stream bank erosion model, and a land surface erosion model are implemented in a program written for general use with a Microsoft® Excel Graphical User Interface. The functionality of this model, Swarthmore Subwatershed-Scale Nonpoint Source Pollutant Model (SSSN) is demonstrated through a case study application to the Little Crum Creek Watershed, located in the suburban area near Philadelphia, Pennsylvania. The predicted loads are found to be within a reasonable margin of hourly simulation models and previous applications of more complex models, indicating its utility as a tool for TMDL regulation. This has been coupled with a resource optimization model, StormWISE, and combined results are presented.

Automation innovations in Autodesk's recently released water resource engineering software allows civil engineers to more efficiently and economically complete stormwater analysis and design projects. This paper highlights the scope, principal findings, and conclusions of a water resource management study conducted by Bolton & Menk, Inc. for the City of Ramsey, MN that utilized hydrologic modeling software from Autodesk called Storm and Sanitary Analysis (SSA), formerly called StormNET and herein referred to as Autodesk's SSA. The overall scope was to combine research, mapping, land use analysis/planning and hydraulic design to create a detailed design tool that the City could use for growth planning and infrastructure replacement. A 30 square mile metropolitan area consisting of 7 separate watershed management areas and approximately 4100 individual hydraulic elements was modeled using Autodesk's SSA. The seamless integration of Autodesk's SSA with Computer Aided Drafting (CAD) and Geographic Information System (GIS) software allowed the project to be completed under the aggressive deadline of 5 weeks. The hydrologic models, combined with an extensive Surface Water Management Plan (SWMP) report, was delivered to the City to be used as a set of planning tools to minimize the impacts of future development goals on the fragile water resources in and around the City of Ramsey.

The effects of stormwater detention basins with specified release rates are examined on the watershed scale with a Hydrological Simulation Program-FORTRAN (HSPF) continuous-simulation model. Modeling procedures for specifying release rates from detention basins with orifice and weir discharge configurations are discussed in this report. To facilitate future detention modeling as a tool for watershed management, a chart relating watershed impervious area to detention volume is presented. A case study of the Blackberry Creek watershed in Kane County, Ill., a rapidly urbanizing area seeking to avoid future flood damages from increased urbanization, illustrates the effects of various detention basin release rates on flood peaks and volumes and flood frequencies. The case study compares flows simulated with a 1996 land-use HSPF model to those simulated with four different 2020 projected land-use HSPF model scenarios — no detention and detention basins with release rates of 0.08, 0.10, and 0.12 ft³/s-acre, respectively. Results of the simulations for 15 locations, which included the downstream ends of all tributaries and various locations along the main stem, showed that a release rate of 0.10 ft³/s-acre, in general, can maintain postdevelopment 100-year peak-flood discharge at a similar magnitude to that of 1996 land-use conditions. Although the release rate is designed to reduce the 100-year peak flow, reduction of the 2-year peak flow is also achieved for a smaller proportion of the peak. Results also showed that the 0.10 ft³/s-acre release rate was less effective in watersheds with relatively high percentages of preexisting (1996) development than in watersheds with less preexisting development.

This presentation describes the detailed laboratory tests of biofiltration media that is being considered for use in engineered stormwater treatment systems recently proposed for a large field laboratory testing site in the southwestern United States. These stormwater treatment systems were designed to treat 90% of the long-term runoff volume from drainage areas ranging from 5 to 60 acres at the site. The pollutants of interest for the project include cadmium, copper, lead, and dioxins, and the effluent concentrations had to meet design criteria that are based on numeric effluent limits that are applied to stormwater discharges through the site's NPDES permit. An additional feature of the project is that existing runoff concentrations for the pollutants of interest are generally below levels typically seen in urban and industrial stormwater runoff, therefore the tests needed to simulate site-specific conditions by adjusting raw influent samples to representative, where possible. The media tested vary widely in terms of cost, performance, and maintenance requirements. However, because of the large volume of media specified for the proposed designs, unit volume cost savings (during construction) are potentially significant if media volume and types can be optimized. Furthermore, the potential for long-term cost savings is also significant, and therefore this study also considers life-cycle costs (e.g., media replacement frequency) and maintenance problems (e.g., clogging frequency). This optimization activity should result in improved predictions of life-cycle costs, of pollutant removals over the media's lifespan, and of maintenance issues and intervals, and should result in improved design and performance when installed in the field.

Selecting the best media for a specific situation is critical when designing a biofilter or bioinfiltration stormwater control practice as the media affects the amount of runoff that is treated and the level of treatment that can be obtained. Appropriate hydraulic characteristics of the media, including treatment flow rate, clogging capacity, and water contact time, are needed to select the media and drainage system. This information, in combination with the media's ability to capture targeted pollutants with minimal clogging given the appropriate contact time, can be used to predict the performance of a biofilter device. This paper presents a series of tests being conducted to determine the hydraulic characteristics of sand-based filter media (having a variety of particles sizes representing a range of median particle sizes and uniformity coefficients) during pilot-scale trench tests. The drainage rate in biofiltration devices is usually controlled using an underdrain that is restricted with a small orifice or other flow-moderating component. These frequently fail as the orifices are usually very small (<10 mm) and are prone to clogging. A series of tests are conducted using a newly developed foundation drain material (SmartDrain^TM ) that offers promise as a low flow control device with minimal clogging potential. A pilot- scale biofilter using a fiberglass trough 3m long and 0.6 x 0.6m in cross section is used to test the variables affecting the drainage characteristics of the SmartDrains^TM (such as length, slope, hydraulic head, and type of sand media). The results indicated that slope of the SmartDrain^TM material had no significant effect on the stage-discharge relationship whereas the length had a small effect on the discharge rate. The information collected during this study will assist stormwater managers in the design of biofilters needing a slowly draining device.

Establishing a stormwater charge program that is both an effective funding source and is considered fair and equitable by the public is a challenge. The program has to provide a quantifiable benefit to the people paying the fee or assessment. This requires significant efforts to properly convey to the public the services they will be provided for their money to address flooding, water quality, maintenance, and associated administration. In conjunction with stormwater program work for several Florida clients, the author has conducted a study of Florida cities and counties with existing stormwater utilities in place or with programs under implementation which incorporate a wide variety of credit systems. This paper looks at the basis for providing credits and credit system, issues related to success in implementation, public perception, difficulty in management, and adaptability to changing conditions.

This paper will discuss how the application of Environmental Site Design Strategies (ESD) and the application of Low Impact Development (LID) storm water treatment can not only mimic the pre-development runoff curve number, but also remove non-point source pollutants from post-development runoff. ESD requires that civil engineers completely reevaluate the processes that they use to design a residential subdivision. ESD requires that the civil engineer evaluate the topography, soils, hydrology, vegetation and habitat on the site prior to the site design. This presentation will outline the necessary steps to evaluate the environmental parameters of the site prior to the design of a project. The environmental parameters to be evaluated include wetlands/watercourses/vernal pools, flood plains, steep slopes (generally >25%), unusual trees or vegetative systems, soils with high or moderate infiltration abilities, and other natural features. The ESD process is critical to achieving the LID goal of Hydrologic Transparency. By the implementation of LID treatment systems to treat runoff at its source, volumetric changes in runoff can be reduced and pollutants associated with non-point source runoff can be reduced through sedimentation, filtration, absorption and various chemical and biological reactions. Through the preservation of large extents of natural vegetated systems on a site, an additional environmental benefit can also be achieved. The preservation of large, contiguous areas of woodlands will provide a natural environment for the sequestering of carbon and the release of oxygen to the atmosphere. Lastly, this paper will show how the changing of the current development paradigm of prescriptive regulations to one utilizing ESD and LID, many of the adverse environmental impacts associated with development can be minimized while providing positive environmental benefits.

The drainage systems on Interstate Highway 80 (I-80) at Emigrant Gap in California were built in 1950s. After more than 50 years of service, most of these systems are in poor conditions and need major rehabilitation. A procedure has been developed to perform hydrology and hydraulic analysis for these systems, based on information available to design engineers, including as-built plans, Geological Survey (USGS) maps, aerial images, etc. The design flood volumes are calculated using the Rational Method and the National Resources Conservation Services TR-55 method, while the hydraulic capacities of drainage systems are calculated using the software program CulvertMaster. The results show that the capacities of many culverts are reduced as a result of the proposed rehabilitation work, which is not expected by engineers who used to believe that a smoother surface might offset the reduction in cross section area on flow capacity. This paper summarizes the procedures and methods used in this project to determine the final rehabilitation treatments.

The EPA's Kansas City, MO demonstration project on the use of green infrastructure to minimize combined sewer overflows will use a variety of integrated practices and modeling approaches. This extensive project will collect data before, during, and after implementation of a variety of control practices in a 100 acre pilot subwatershed, and in a parallel control subwatershed. The reduction of discharges to the drainage system during wet weather will be calculated using models and verified through field monitoring. The continuous models will determine the decreased amount of stormwater discharged for each event as the storage and infiltration facilities dynamically fill and drain over an extended period of time. WinSLAMM, the Source Loading and Management Model, conducts a continuous water mass balance for every storm in the study period. As an example, for rain barrels, water tanks or cisterns, capturing roof runoff, the model fills the available storage during rains. Between rains, the storage tank is drained according to the water demands for each month. If the tank is almost full from a preceding close rain (and not enough time was available to drain the storage tank), excess water from the event would be discharged to the drainage system after the tank fills. Curb-cut rain gardens/biofilters along a street are basically a cascading swale system where the site runoff is allowed to infiltrate. If the runoff volume is greater than the capacity of the rain gardens, the excessive water is discharged into the combined sewers. When evaluated together, the cisterns treat the roof runoff first, but the excess water is discharged to the curb-cut rain gardens for infiltration. The continuous simulation drains the devices between events, depending on the interevent conditions. As an example, if 200 ft² rain gardens were used for each house in the 100 acre pilot subwatershed, up to about 90% of the annual roof runoff from directly connected roofs may be infiltrated. The use of a single 35 gallon rain barrel per house is expected to provide about a 24% reduction in directly connected roof runoff through irrigation to match ET. However, more than 25 rain barrels per house would be needed to reduce the roof's contributions by 90%. The use of rain gardens having a total area of 80ft² and two 35 gallon rain barrels per house can collectively reduce the runoff from directly connected roofs by about 90%. Modeling during the project will involve a wide range of potential controls, well beyond the few examples noted here.

Johnson County, Kansas, an urban fringe county of the Kansas City metropolitan area, has a current population of over 540,000 and an average annual growth rate of 10,000 people per year. Since establishing a Stormwater Management Program in the early 1990's, Johnson County has conducted county-wide studies to identify flooding problems and implemented numerous flood mitigation projects. Over the past 18 plus years, the program has helped fund over $200 million in flood mitigation projects across the county, removing numerous habitable buildings from the floodplain, improving road crossings, and improving stormwater conveyance. In 2004, Johnson County and 12 NPDES Phase II cities within Johnson County were issued their first NPDES Phase II permit by the Kansas Department of Health & Environment (KDHE). It was clear at that time that the stormwater program should be refined to include consideration of both water quantity and water quality. Over the last 5 years, Johnson County has engaged in numerous efforts to support local and regional efforts to address stormwater quality and quantity. This paper explores programs that have been initiated to achieve a variety of goals including: better characterization of existing water quality in Johnson County; improving regional stormwater Best Management Practices (BMP) standards; monitoring of BMPs; participation in multi- jurisdiction watershed initiatives; increasing public education and involvement; and supporting city efforts to address water quality and quantity. Detailed information on these programs, overall costs, staff requirements, and lessons learned will be provided to help other similar programs effectively implement a comprehensive stormwater program that can address both water quantity and quality.

The City of Santa Monica's integrated Watershed Management Program requires post-construction Best Management Practices (BMPs) for construction projects to reduce the amount of stormwater runoff (rainwater harvesting) and pollution, and to improve runoff quality entering the Santa Monica Bay. While the city's watershed management program has been and continues to be hugely successful in promoting Low Impact Development (LID) strategies for individual parcel projects, the transportation grid is a difficult area to incorporate BMPs. Transportation infrastructure is less manageable than an individual parcel and involves other complexities of development, such as underground utilities, drainage grade changes, parkways, and traffic flow. To demonstrate the feasibility of incorporating the LID strategy in an ultra-urban, built-out setting, Santa Monica built a green street. Additional strategies for the transportation grid are also being applied throughout the city in a long-term project-oriented plan funded by the city's Clean Beaches and Ocean parcel fee. This paper will discuss efforts to implement LID strategies throughout the transportation infrastructure, which can become the new standard for urban infrastructure redevelopment in addressing challenges facing urban runoff management.

When applying a pollutant concentration limit to a stormwater discharge many issues must be clarified to demonstrate compliance. This paper summarizes how a modeling approach was used to meet pollutant concentration requirements in stormwater. Neenah Foundry, Neenah, Wisconsin was in violation of the state guidelines for total suspended solids, aluminum, nitrate/nitrite, copper, and zinc stormwater concentrations. These violations were based on "grab" sampling conducted once per year at the site's three outfalls. Through discussions with the Wisconsin Department of Natural Resources (WDNR), a course of action was developed that included conducting event based monitoring at an outfall and incorporation of the monitoring information into a model. The monitoring: 1) characterize the site's stormwater pollutant concentrations, 2) verified that permit benchmarks were in fact being exceeded, and 3) provided data (including particle size distribution) to calibrate a pollutant loading model (WinSLAMM) for use in the management practice design. Through application of this approach the regulatory agency accepted a modeled pollutant concentration target expressed as an average annual concentration for permit compliance purposes.

The City of Dublin, Ohio's original Stormwater Master Plan (SWMP) was intended to provide a "living document" to control and manage stormwater impacts by establishing appropriate development regulations and a roadmap for capital improvement planning. Since the SWMP, the City of Dublin (City) has experienced a 30-percent population increase and corresponding land development, including the construction of 165 stormwater control facilities. The City undertook the 2009 SWMP Update to determine if the SWMP and ordinance had performed as intended. This paper summarizes the activities and findings of the SWMP and 2009 SWMP update. Using computer modeling, the impacts from development on peak discharge rates and the hydraulic grade line within the streams were examined. In conclusion, the City's current stormwater management policy has had a significant impact on minimizing effects to the receiving streams.

The Maryland Stormwater Management Act of 2007 mandated a change in the state's approach to stormwater management for new development, called Environmental Site Design (ESD). In 2008, The Maryland Department of the Environment (MDE) developed new design guidance to reflect this approach, with the following goals: (1) Improve the use of environmentally sensitive development and other site planning techniques listed as Stormwater Credits in the 2000 Manual. (2) Integrate site planning and structural controls in one procedure. (3) Encourage the use of onsite or micro-scale structural controls for both water quality and channel protection treatment, and discourage the use of end-of-pipe treatment. As part of the effort, MDE contracted with KCI to conduct a pilot test of the revised design guidelines. The first task was to identify recently completed site development plans designed according to the current manual to use as scenarios for the pilot study. Three were selected: one commercial site and two residential sites with different densities. The core of the pilot project was to test the proposed sizing criteria and SWM alternatives in the draft manual. KCI developed a complete redesign of the stormwater management facilities for all three sites, focusing on non- structural and micro-scale practices described in the draft manual, including runoff disconnection, sheetflow to buffers, infiltration, swales, filters, and bioretention. Feasibility of the draft procedures was verified with TR-20 modeling, which provided hydrograph analysis to compare the ESD approach with the conventional design in the original development plans. The results showed that the ESD approach to stormwater management was feasible for a wide range of sites and that the designs using the new criteria could meet the same goals for stormwater control as the conventional designs.

Cumulative impacts and losses occur in watersheds as humans develop them. Cumulative losses to the environment occur, and cumulative impacts occur to constituents in the downstream part of the watersheds in terms of flood hazards. The paper reviews how multi-objective management is fundamental to urban watershed management and can address cumulative effects from development. The paper encourages the use of incentives and established processes to address the cumulative effects, specifically both the basic technical and organizational processes for developing urban watershed planning. Technical processes for watershed environmental planning are introduced for comparing green solutions, including best management practices and stream corridor rehabilitation. The paper demonstrates how habitat units may be used to maximize the net benefits for multipurpose projects. The basic steps for these processes clarify watershed planning work and strengthen collaboration, which is part of building strong partnerships in our Nation's watersheds.

Urban stormwater runoff has degraded the 1,260 acre University of Wisconsin-Arboretum. An innovative, watershed-wide, multi-stakeholder stormwater management planning effort facilitated by the University of Wisconsin is being used to guide remediation of failing stormwater management facilities. Beginning with a watershed-wide stormwater management plan created with a community group (the Friends of Lake Wingra), a facility stormwater management planning process was developed for the UW-Arboretum property surrounding Lake Wingra (Madison, WI). The subsequent 2-year collaboration between Arboretum ecologists, adjoining municipalities and stormwater management engineers resulted in a plan identifying stormwater management options for each of eight major urban stormwater outfalls. While differences in knowledge and values among the participating professions initially inhibited close collaboration, using a facilitated, iterative process of dialog and plan review improved cross-discipline communication and respect, allowing the planning effort to come to fruition. The centerpiece of the plan was a unique set of stormwater management values and guiding principles that reflect the UW-Arboretum's mission of "conserving and restoring Arboretum lands, advancing restoration ecology, and fostering the land ethic." These values and guiding principles served as a touchstone for resolving inter-disciplinary differences during the planning process. Consequently, this stormwater planning effort and its subsequent implementation, were notable for the degree of cross-disciplinary collaboration among engineers, municipal managers, restoration ecologists and the public. The outcomes of this planning activity include: (1) An inter-governmental agreement (IGA) allocating funding for stormwater improvements that is pro-rated by runoff contributing area; (2) Source water infiltration, treatment and flow reduction in the contributing watershed; (3) Creation of innovative stormwater treatment, research and outreach facilities at the UW- Arboretum; (4) Stormwater management self-assessment by businesses in the watershed; (5) Teaching and research on stormwater best management practices (BMPs) and ecological impacts; (6) Reduction of impacts to Arboretum natural areas and watershed ecosystems. This experience serves as a case study example for the many other instances where engineers must engage in multi-stakeholder or cross-disciplinary planning activities.

This paper documents the integration of a Geographic Information System (GIS), the Source Loading and Management Model for Windows (WinSLAMM) and database calculations into a system that calculates loadings over multiple watersheds. The presented method creates GIS files representing model input parameters, including soil classification, land use, drainage type, and existing BMPs. The batch editor module of WinSLAMM creates and analyzes required model data files. Database post-processing of WinSLAMM output determines pollutant loads and loading rates for each polygon created in GIS and the percent of TSS reduction achieved under existing conditions. Symbolizing the polygon pollutant loading rate density (lbs/acre/yr) under existing management conditions facilitates BMP site selection. Database calculations assess the loading to be removed by the potential BMPs, and this process is applied iteratively until pollutant reduction goals are met. This methodology may have widespread application as Total Maximum Daily Load (TMDL) calculations are required for other pollutants modeled by WinSLAMM.

Identifying pollutant reduction strategies is a key component to meeting total maximum daily loads (TMDLs) for impaired water bodies. Reduction of total nitrogen as a pollutant in stormwater runoff is particularly challenging due to the lower relative treatment efficiencies of structural best management practices (BMPs) such as wet detention ponds. Enhancing BMP systems with vegetative buffers or filtration has proven to be an effective method to increase nitrogen reduction. For pre-existing urban areas, there is limited opportunity to implement structural BMPs due to land availability. Focusing efforts on identifying potential implementation of BMPs in transitioning rural land use areas prior to the occurrence of intense development allows for effective set asides for total nitrogen reduction strategies. The authors have conducted a feasibility study for total nitrogen reduction opportunities as part of the Stormwater Management project for the Royal Trails Subdivision. The transitioning subdivision is only approximately one-third built out. This presented a unique opportunity to allow the conceptualization of land intensive BMPs such as vegetative swale treatment and pond treatment while space is still available. These BMPs will assist in meeting the regional nitrogen reduction goal within the Wekiva River Protection Area.

The City of Fond du Lac, Wisconsin completed a comprehensive stormwater planning process to meet the Wisconsin MS4 permit regulatory requirements. In Wisconsin, the MS4 permit includes a requirement to retrofit existing lands with management measures to reduce the existing sediment load by 40 percent on an annual basis. One component of the City's plan included identifying locations that could be retrofit to construct stormwater quality practices. One high priority site identified was the Rueping-Macy site. The site's location and land use made it ideal for a stormwater detention pond. However, the site has some unique characteristics to create a challenging design. The property was formerly occupied by a leather tanning facility and was classified as a Brownfield following closure of the facility. Subsurface investigations revealed elevated concentrations of various heavy metals. The proposed pond will be located on two parcels and the City did not own either parcel. The southern parcel was tax delinquent and its actual owner was difficult to identify. The northeast parcel was, however, available for sale. The pond will be served by two existing stormwater lift stations and both will be retrofitted to direct stormwater to the pond. Each challenge was overcome through planning and design and the pond will be constructed in late 2010/early 2011.

When natural or agricultural land is converted for (sub)urban or commercial use, the addition of impervious surfaces becomes a dominating factor in the new urban hydrologic regime. To help minimize the negative hydrologic effects of this land use change, urban best management practices (BMPs) are continually being developed. Several BMPs have been developed to allow infiltration on certain transportation surfaces. Among others, these include substituting traditional pavement with pervious pavers. Small gaps between paver blocks typically represent about 10% perviousness by area. It is generally accepted that infiltration is maintained on this portion of the surface, resulting in an overall reduction in runoff discharge, versus a traditional pavement. However, surface sealing resulting from silt or clay particles deposited by water, wind, or vehicles may result in reduction or elimination of infiltration. To test the extent to which this phenomenon can influence runoff and infiltration dynamics, a series of laboratory rainfall simulations was performed on 1.0 x 0.6 x 0.2-m boxes a pervious paver surface located down slope from a soil box representing an erodible soil surface area. Rainfall representing a 5-yr return period storm was simulated and timed runoff and infiltration samples were collected to determine discharge rates of water and sediment from each 1- m long section. Results indicate that almost all of the rainfall and run-on applied to pervious paver surfaces initially infiltrated. However, infiltration rates decreased and runoff rates increased with successive rainfall events, and after 10 to 11 5-yr rainfall events, siltation and surface sealing between paver blocks prevented infiltration from taking place entirely. This indicates employment of pervious paver blocks requires ongoing maintenance to prevent surface silting and sealing for sustained effectiveness.

Many research studies have been published regarding the treatment efficiency of bioretention for a wide variety of pollutants found in urban stormwater runoff. However, limited information is available on predicting the treatability of these pollutants between media and between sites. Predicting the treatment ability of bioretention/infiltration/filtration media is a function of both media and water chemistry. This paper begins that meta-analysis of pollutant removal as a function of chemistry. The results presented here are from a single project evaluating candidate bioretention media to meet NPDES numeric effluent limits for industrial stormwater discharges and are based on a limited number of samples. As additional data become available in the spring, the analysis will be expanded. The water chemistry greatly affects the forms of the pollutants, and many metals that are in the dissolved phase have been shown not to be ionic. These complexed metals have valence charges that may make their treatment more difficult. The preliminary results for soil chemistry effects indicate that the media that appear to have the best removal ability for a wide range of metallic pollutants are those that have both cation exchange ability and comparatively high organic matter content; however these chemical characteristics cannot be used to measure media exhaustion, except for the pure ion exchange resins and possibly for ionic forms of the cations. For the removal of the dissolved fraction of metals, this also may require a neutral to acidic media pH because of the generally increased solubility of metals at lower pHs. Lower pHs and higher organic matter contents, however, must be evaluated further if phosphorus removal is also desired since phosphorus is removed better at higher pHs and lower organic matter content (organic matter is a source of P). These results also highlight the trade-offs in pollutant capture versus cation/mineral/pollutant export when using ion-exchange media. Design of bioretention devices for effective treatment, and especially to meet permit limits, requires a greater understanding of the interaction of water and soil chemistry on a site, with a focus on the chemistry of the dissolved fraction.

Nuclear power plants with re-circulating cooling water systems routinely release controlled quantities of tritium with plant water discharge to on-site cooling lakes. Computations are required to evaluate the impacts of tritium releases on the water quality of the cooling lake. A mass balance equation is developed to compute the build up of tritium activity in the cooling lake with specified amounts of tritium discharged from the plant and varying amounts of fresh water withdrawn from and blowdown water discharged to a perennial source, e.g., a river. Different scenarios are evaluated for varying quantities of fresh water withdrawal and blowdown discharges and maximum tritium activity expected in the water in the cooling lake. Limitations on withdrawals from and blowdown discharges into the river are addressed so that the water quality of the receiving stream is not impaired due to unacceptable tritium concentrations.

The Conkey Pond and Northland Creek channel naturalization and floodplain lowering projects consist of a wet stormwater detention pond and naturalization of 286.5 meters (940 feet) of navigable stream in an industrial area in the City of Appleton, WI. Sustainable features include extensive use of natural materials and vegetation that reduce maintenance costs, improves water quality, add biodiversity and enhances habitat and aesthetics. These two facilities reduce downstream flood stages by about 0.82 meters (2.7 feet), and reduce TSS loadings within the city by 27 tonnes/year (30 tons/yr), which is about 11 percent of the remaining citywide TSS removal goal. Additional benefits include naturalization of a concrete lined channel, and the creation of wetlands in shallow depressional areas within the newly created floodplain.

The examples of sustainable water management activities in the Madison, Wisconsin metropolitan area illustrate several challenges for mitigating hydrologic impacts. (1) A decrease in evapotranspiration with site development is a major water balance impact that has significant implications for using stormwater infiltration to maintain predevelopment groundwater recharge rates and runoff volumes. (2) Basing water management standards on the hydrologic and ecological condition of the watershed offers both advantages and challenges. (3) Groundwater withdrawals for water supply combined with diversion of treated wastewater create groundwater impacts that stormwater infiltration alone is unlikely able to mitigate. (4) On-site stormwater management must be integrated with regional water supply and wastewater planning to most sustainably manage water resources. Understanding and addressing these challenges can lead to new opportunities to improve water resource management at site-specific and regional scales.

Impacts on water quality due to land development projects are widely known. The adverse impacts of pollutants associated with non-point source are becoming more pronounced in many areas of the country. These types of pollutants can easily affect water quality in streams and lakes. This paper will discuss the use of, the benefits and potential drawbacks of certain models, such as SLAMM (Source Loading and Management Model) and the P8 model (Program for Predicting Polluting Particle Passage through Pits, Puddles and Ponds) along with the Simple Method. By the use of the Simple Method, it will be shown how the calculation of pollutant loads can be determined both on an annual basis and for the 90 percent storm (1" of rain). In particular, it will be demonstrated how the loads determined for the 90 percent storm will provide a reasonable assessment of impacts that can readily be understood by local land use agencies. The next step in this process is the proper design of storm water treatment systems. In order for the treatment systems to be effective at the removal of non-point source pollutants, the design parameters must provide certain benchmarks. The various aspects of treatment systems, such as hydrologic capacity, flow paths and vegetative systems will be discussed along with the importance of each component. It will be shown how pollutant removal efficiencies for various treatment systems can be applied to the calculated loads to demonstrate the effectiveness of the storm water treatment system to remove the pollutants. The myriad benefits of the creation of a treatment train versus a stand alone system will also be discussed. In conclusion, the many environmental benefits of this approach to maintaining the health streams and lakes will be provided.

Many older communities were developed prior to the existence of regulations and design guidance for managing floodplains and other wet weather flows. This has resulted in untreated stormwater runoff that floods roadways, inhabited structures and floodplains. A common limitation is that urban residential areas were built without the preservation of natural areas or publicly owned open space. These construction practices limit opportunities to implement structural measures to mitigate increased stormwater runoff volumes and elevated pollutant loads. Low Impact Development (LID) small scale, on-site structures provide a method for mitigating stormwater runoff within the confines of the limited open space available. Fairfax County, Virginia, has been working with two residential communities to mitigate flooding concerns at the sub-watershed scale. This paper describes the processes used to select and evaluate flood mitigation alternatives, how the LID opportunities were selected and implemented, and the resultant mitigation of the hydrologic impact of these built areas.

Water-sensitive urban design (WSUD) is an integrated water management system that encompasses low-impact design, water conservation and recycling, water quality management, and urban ecology. WSUD increasingly is becoming a key component in establishing appropriate sustainable supply planning in urban areas around the globe, as well as in contributing to flood prevention and water quality protection. Water resource management is one of the greatest challenges of the present century. As populations climb, per capita use increases, and current water supplies grow shorter, water resources are becoming more critical globally. Most urban areas face difficult choices and expensive solutions to meet existing and future demand. WSUD provides one of the key approaches to resolving these dilemmas. This paper describes newly emerging models of WSUD and its implementation. An overview of key WSUD planning and design principles is presented, followed by the WSUD toolkit and description of an emerging sustainable communities planning tool developed by AECOM—the Sustainable Systems Integrated Model^TM (SSIM). SSIM provides a quantitative view of the effects of urbanization and allows for comprehensive systems-based sustainable communities planning founded on climate change mitigation goals. Several case studies of urban water resource management are also presented—showing how WSUD can improve functional water infrastructure while beautifying community development and enhancing sustainable practices that reduce climate change potential and meet compliance mandates.

Soil erosion of hills affects the productivity of agriculture lands and threatens our earth environment. There are several factors that trigger and sustain soil erosion, such as climate, soil type, soil surface roughness, cropping, and land management practices. This laboratory study examines the role of the rainfall intensity on soil surface roughness development and the transport/deposition of the eroded material under different experimental scenarios. Surface roughness is related to management practices and has been one of the factors that did not receive considerable attention. One hindrance of previous studies was the lack of a system and robust methodology for performing adequate acquisition of the soil surface micro- topography. Herein, a state-of-the-art laser scanner technique was utilized, providing a spatial resolution of 0.5 mm. The surface heights for the entire soil surface were imported into the ArcGIS 9.2 software in order to obtain the Digital Elevation Model (DEM), while the built-in Arc Hydro tools were used next to attain the drainage networks, flow direction, flow accumulation, stream definition, and stream segmentation. Data sets obtained from this study will be used as input files for numerical models such as the RILL1D to simulate rill development and reproduce measured values of sediment transport rates.

The Cheyenne River Watershed below Angostura, in western South Dakota, is listed as impaired by the state of South Dakota for total suspended solids (TSS). The water-quality standard includes a beneficial use of warm-water permanent fish life propagation and a TSS numeric criterion for a single sample of 158 milligrams per liter (mg/L). A Total Maximum Daily Load (TMDL) watershed assessment was initiated in May 2004 focused on TSS to address this impairment. The project was a two-phase assessment with the first phase focused on historic data analysis. It became clear during the first phase that TSS concentrations routinely exceed current numeric criteria and that site-specific criteria may be necessary. The U.S. Environmental Protection Agency (EPA) requires physical, chemical, and biological data to support adoption of site-specific criteria. To meet these requirements, the second phase of the TMDL assessment focused on the collection and analysis of biological, physical, and water-quality data. Sixty-four sites were established for classification and assessment of physical habitat and the benthic macroinvertebrate community following the methodologies from the Environmental Monitoring and Assessment Program (EMAP) and from South Dakota's Standard Operating Procedure for biologic and physical habitat data collection. Sites were distributed throughout the watershed to characterize the habitat gradient from the upper reaches down to the confluence with the Missouri River. Measured and calculated physical habitat metrics were analyzed using principal component and cluster analysis to characterize the condition of the Cheyenne River Watershed and the variability contained therein. Benthic macroinvertebrates were collected and Index of Biotic Integrity (IBI) scores were calculated at all sampling locations. Biologic sampling of the benthic macroinvertebrate community suggests that there may be some level of impairment of the aquatic ecosystem in the watershed when compared to watershed reference condition; however, this impairment is most likely more closely related to other water-quality constituents than to sediment. Review of previous fisheries studies conducted in the watershed suggests that the Cheyenne River hosts a wide variety of fish species, suggesting that some level of the fisheries beneficial use is being met; however, biotic integrity based on vertebrate populations have not been calculated as part of previous fisheries assessments. Water-quality samples were collected at 19 sites over a 2-year period, with a mix of baseflow and storm event sampling. Thirteen sites were U.S. Geological Survey (USGS) sites where real-time discharge and water-quality data were available. Continuous-stage recorders were installed at six sites where stage/discharge measurements were recorded. Two sites were South Dakota Department of Environment and Natural Resources (SD DENR) Water-Quality Monitoring (WQM) stations where discharge was the only added data collection. These data were used for a statistical analysis of water quality as well as for calibration/validation of the watershed model. The second phase of the TMDL assessment confirmed that natural background for TSS far exceeds the current numeric criteria. Based on the findings of this project, it was determined that a site-specific criterion is appropriate for the Cheyenne River for TSS. The final product of this assessment will be a recommended new numeric criterion for TSS.

Population growth and the resulting urban sprawl are increasing the impervious surface area throughout the state of Minnesota. From 1990 to 2000, impervious surface area increased in Minnesota by 44%. More importantly, this included increases of more than 100% in 20 of the 81 major watersheds in the state (Bauer et al., 2007). These increases in impervious surface area are worrisome as they prevent infiltration which is an effective, natural method for treating stormwater and thus reducing its impact upon surface waters. Because most non-point source (NPS) pollution results from a lack of infiltration, rain events in areas with a high percentage of impervious surfaces cause water to accumulate a multitude of pollutants including harmful anthropogenic organic compounds, nutrients, pathogens, and particulates before washing off into nearby waterways. The concern stemming from NPS pollution has increased dramatically with increasing urbanization and as a result, multiple best management practices (BMPs) have been identified and established to minimize the impact of storm events on surface water quality (MPCA, 2005). Current practices to stem the effects of stormwater runoff include various forms of stormwater ponds, wetlands, channels and engineered systems involving filtration and settling techniques. Previous studies performed for the US EPA show high pollutant removal for phosphorus and total suspended solids in both pond systems and wetlands, with the ponds performing better (Winer, 2000). Neither BMP was very effective at removing metals and nitrogen though (Winer, 2000). Overall stormwater ponds and wetlands tend to be the most effective BMPs when the removal of all major pollutants is assessed. Unfortunately these systems lose effectiveness with age and thus may become ineffective if they are not monitored and maintained correctly (Winer, 2000). In this study, we have used a wireless sensor network to evaluate BMPs and water quality in two urban creeks. Shingle Creek flows through residential, commercial, and industrial areas, has a highly impervious watershed, and discharges into the Mississippi River in Minneapolis, MN. Minnehaha Creek is fed from Lake Minnetonka and winds through the western suburbs of Minneapolis, MN. The landscape surround this creek ranges from agricultural and recreational to highly urbanized as it approaches its discharge at the Mississippi River. The flow of this creek is regulated by a dam in Lake Minnetonka, and when this dam is closed the flow is primarily a result of stormwater runoff, and thus, so is the pollutant loading.

Mitigating hydrologic impacts associated with redeveloping a portion of an existing industrial site can be challenging. The designer's challenge is to help the client achieve the development need while finding a way to overcome site constraints and comply with applicable regulations. This paper presents the design strategies employed to meet the site redevelopment needs and regulatory requirements at a power plant located in Portsmouth, New Hampshire.

The Hydrological Simulation Program-Fortran (HSPF) is a semi-distributed watershed model, which simulates hydrology and water quality processes at user-specified spatial and temporal scales. Although HSPF is a comprehensive and highly flexible model, a number of investigators noted the model's limited capabilities in representing and simulating best management practices (BMPs), such as detention basins and infiltration trenches. We present herein a stand-alone web-based HSPF BMP Toolkit that allows HSPF to represent and simulate storage and infiltration BMPs in a more comprehensive way.

Non-point source pollution of surface waters with sediment, nutrients, and other agrichemicals is a growing public and regulatory concern. Pollutant export from agricultural fields is often estimated using computer models or simulated runoff experiments, rather than with actual field-scale measurements. Pioneer Farm, a 174 hectare (430-acre) mixed-livestock farm associated with the University of Wisconsin-Platteville is intensively instrumented with flumes and automated samplers on subwatersheds ranging from 1 to 28 hectares (3 to 70 acres) in size. The field devices were modified to quantify winter runoff events, which are notoriously difficult to monitor and are rarely reported in scientific literature. Through monitoring, it was determined that winter runoff volumes can be a significant fraction of total annual runoff. Runoff from four years of monitoring is quantified and the relative importance of winter runoff to the annual export of sediment, nitrogen and phosphorus is highlighted. In many cases, the majority of the annual pollutant export occurs during a relatively brief time period between mid-February and mid-March. The impact of the variability in winter precipitation and field conditions, and the timing of spring season warmer temperatures and rainfall is demonstrated.

To quantify nutrients discharged from agricultural fields under different manure application practices, six field stations were installed to automatically sample water and remotely monitor flow and temperature in agricultural tile drains and ditches. Each station included a datalogger, RF radio, automated sampler, and flow sensor, with some remote stations powered by solar panels. A novel sampling methodology, tested at two of the stations, used real-time volumetric flow data as input to a hydrograph model encoded in the datalogger to generate hydrograph-specific sampling schemes for sampling at different flow-proportional frequencies. This unique sampling methodology produced high-resolution data independent of the hydrograph size, providing additional insight into how environmental processes influence the quality and quantity of flow from an agroecosystem on an event-by-event basis. An initial assessment of the results suggests that the relative importance of environmental controls on the transport of nitrogen and phosphorus exhibits high temporal variability.

State and Federal governments have approached mitigation of nutrient transport from animal feeding operations with both regulatory and volunteer-based models. The Comprehensive Livestock Environmental Assessment and Nutrient Management Planning (CLEANeast^TM) Project is a 4-year, 27-state voluntary program funded as a cooperative agreement with the U.S. Environmental Protection Agency to reduce nutrient transport to surface waters from animal feeding operations. The Project offers no-cost, confidential manure management planning to livestock and poultry farms who volunteer. Tools were created to use with existing State and Federal manure management planning software to not only support large animal feeding operations required to comply with water quality standards but also to encourage small, unregulated operations to implement nutrient reduction measures voluntarily. Statistics on participation and the management practices recommended by field experts provide insight into the viability of volunteer programs, diversity in regionally-based interests, variations in management practices, and benefits to impaired receiving waters.

California water providers are facing a number of challenges in maintaining reliable and clean drinking water supplies. Drought impacts have affected the availability, quantity and quality of the state's source waters and water providers must develop strategies to contend with these supply changes. To evaluate its long-term water supply challenges and solutions, Eastern Municipal Water District (EMWD) is developing an Integrated Resource Plan (IRP). The IRP provides a guide to leveraging the flexibility of their very complex supply system. The goal for the IRP is to seek fully integrated strategies utilizing EMWD's diverse range of supply and demand resources, including treated imported water, raw imported water, recycled water, local surface water, and groundwater systems. To aid in the evaluation of these operational strategies, a dynamic system model (System Model) of EMWD's integrated systems is being developed using the Powersim dynamic simulation software. The System Model parallel processes the dynamic operation of EMWD's treated water, raw water, recycled water and groundwater supply systems, including all imported water sources, regional and local treatment plants, and natural and artificial groundwater recharge components. Available raw and treated imported water, natural groundwater recharge, and treated and recycled water demands also serve as inputs to the System Model. Model programming allows inputs to be adjusted based on theoretical regional climate change impacts to assess the vulnerability of a water supply portfolio (e.g., combinations of water supply and demand options) to climate change. The System Model evaluates overall system performance of water supply portfolios against multiple planning objectives. The System Model is being used to develop a set of water supply and demand portfolios designed to meet these planning objectives. The most promising portfolios and their corresponding scores will be evaluated using decision analysis software which incorporates EMWD priorities for the individual performance objectives. This paper presents the integrated approach to addressing EMWD's future supply needs and the System Model used to compare the potential benefits and costs of potable and non- potable water supply and demand management options, and support decisions about how and when to implement various system improvements through the 2035 planning year.

Shale formations with gas producing potential are distributed throughout much of the United States. The process required to extract gas from low permeability shale formations, termed hydraulic fracturing or "Tracking," entails injecting large volumes of water, sand, and chemicals at high pressures into the formation, resulting in fractures that increase permeability, allowing the gas to be collected and delivered to the surface. Additionally, wells are generally drilled horizontally underground to increase the area of production for a single well. Whereas variations of the technology have been in use for many years, it has only been in the last decade that the technology has improved to allow economic production from unconventional shale formations on a widespread basis (Airhart, 2007). The technology has been most widely used in the Barnett Shale formation in Texas, which has seen over 13,000 wells developed since 2000 (EIA, 2009; TXRRC, 2009). Portions of the Marcellus Formation, which extends over 95,000 square miles and underlies portions of New York, Pennsylvania, Ohio, and West Virginia, have begun to experience substantial gas leasing and development activity in recent years. The Catskill and Delaware watersheds that provide 90 percent of New York City's unfiltered drinking water supply are underlain by relatively thick sections of the Marcellus that are expected to have high gas production potential (NYCDEP, 2009b). Over 65 percent (∼1,000 square miles) of the NYC watershed could potentially be exploited for natural gas development. Natural gas development activities have the potential to impact the quality and quantity of NYC's water supply through land disturbance, chemical spills, disruption of groundwater flow pathways, water consumption, and waste generation. In recognition of these potential impacts, the New York City Department of Environmental Protection (NYCDEP) has undertaken the project, Impact Assessment of Natural Gas Production in the NYC Water Supply Watershed. The overall goal of the project is to identify potential threats to the continued reliability and high quality of New York City's water supply from future natural gas development activities in or near the NYC watershed. This paper summarizes major findings from this project.

The Romanian Black Sea coast including the Danube Delta region has been severely impacted by erosion, habitat loss and pollution. The Romanian Ministry of Environment (RME) recently sought solutions to these challenges through Integrated Coastal Zone Management (ICZM) planning. In 2008, Black & Veatch (BV) was awarded a United States Trade and Development Agency supported contract from RME to complete a detailed analysis, costing and recommendations for institutional support, for their COASTEROSION program. This study, in particular, recommended Institutional Strengthening to support the program's Geospatial and Related Data Collection System (GRDCS). The Romanian government passed legislation in 2002 supporting ICZM, and in 2004 created a National Committee for the Coastal Zone (NCCZ) to oversee coastal development and management. The NCCZ is currently a voluntary and under-funded organization with limited legislative and operational support. As conceived, this organization should be the focus of and provide the vision for IZCM. However the organization requires important administrative, technical and reporting adjustments to attain its legislative mandate and goals. The BV COASTEROSION team recommended that development and integration be combined under a new Coastal System Operations Center (CSOC). The CSOC would become the critical Institutional Strengthening step for the COASTEROSION program and the effectiveness of the NCCZ. The CSOC would be an operational group with these functions: (1) Providing independent technical analysis including Regional Sediment Modeling (RSM) to support (a) evaluation of the current health of the Black Sea Coast, (b) development of long- and short-term coastal impact assessments (c) development and evaluation of possible alternatives for proposed projects (d) communication of results; (2) Acting as a resource to the NCCZ through the Executive Committee and its Work Groups, supporting new policy, practice, monitoring, and impacts, and for completion of the national strategy for ICZM; (3) Providing ICZM, CSOC, RSM, and GRDCS training and outreach resources for RME and other government ministries, as well as local and regional entities; (4) Managing day to day data operations, maintenance, and management of GRDCS. This paper reviews issues related to ICZM on the Romanian Black Sea and Danube River delta coast, and provide an overview of the CSOC for possible adaptation by other countries involved with ICZM, RSM, training, and communication.

The advancement toward more sustainable communities continues to gather strength. However, the current emphasis on achieving LEED certification is problematic from a water perspective. The focus on prescribed design features and practices means that priority sustainability needs for the watershed may go unaddressed despite the green building and site achieving LEED certification. Without a paradigm that places development design in the context of sustainable community and watershed needs, the nation risks moving further away from its sustainability goals. Research conducted for the Electric Power Research Institute (EPRI) under a grant from the Water Environment Research Foundation (WERF) is aimed at identifying the foundation and support structure for sustainable water infrastructure at the community and watershed scale. Two communities (Tucson-Pima County AZ and Northern Kentucky) and an expert advisory panel were recruited to participate in a retreat to flesh out ideas for a new water infrastructure paradigm. The research team and its community and expert advisory panel representatives identified key principles that provide a foundation for a new paradigm for sustainable water infrastructure. Among the principles that contrast with past and current practices are valuing all water as a resource, moving toward a performance-based regulatory framework, aspiring toward better outcomes, and recognizing true costs while maximizing the value of action. A framework for supporting this new sustainable water infrastructure paradigm has been developed and includes as core elements an integrated planning structure that connects current institutional silos, a technical toolbox to use in the context of performance-based requirements at the watershed and community scale, regulatory flexibility to encourage innovation and affect better outcomes, research and demonstration to build knowledge and capacity, new partnerships and funding mechanisms, and a variety of means for engaging the community stakeholders to broaden support and affect better outcomes.

Using hydrological data of the East River Basin, South China, over the past five decades, this paper analyzed the impact of land use changes and vegetation cover changes on the hydrological system of the basin. It was found that the Normalized Difference Vegetation Index (NDVI) in the Basin is not significantly correlated with natural runoff, annual evapo-transpiration or runoff coefficient. Changes in the conditions of the underlying surface of the river basin arising from land use/land cover changes are the primary factor impacting upon runoff changes in the East River Basin and are the main reason for the increase in runoff in the river basin. Changes in the hydrological system of the East River Basin are subject to the impact of complicated factors, typically the joint impact of climatic changes and human activities.

Based on project scale, dam removal projects boast some of the greatest ecological benefits to aquatic resources. A single dam removal project can restore connectivity to miles of upstream habitats, re-establish sediment balance to downstream reaches, and reduce thermal impacts. While the removal of the dam structure can be fairly straight forward, resource managers are challenged by what to do with the impounded sediments from both a quantity and quality perspective. In many cases resource managers lack the information necessary to make informed decisions about how to manage sediments, which results in the costly excavation and disposal of sediments. The perceived complexity of many available analytical tools that model the transport and fate of sediments prohibits their application, but for the purpose of assessing risk to aquatic resources, these complexities can be overcome through the use of reasonable approximations of input values. Visual site inspections, pebble counts, and hydraulic models can provide the basic inputs to compute sediment loads and develop rudimentary sediment budgets. Recognizing the uncertainty in these empirical computations without calibration, the predicted sediment loads may be less useful than the relationship among loads used to identify sources and sinks in a watershed. These sediment budgets are most useful as screening tools to assess the physical or ecological risks to aquatic resources downstream. As a screening tool, rudimentary sediment budgets can be used by resource managers to determine if impounded sediments should be removed or if it is prudent to conduct additional studies and calibration to justify allowing the impounded sediment to be redistributed naturally by the river. This discussion presents methodologies for data collection, analysis, and interpretation of rudimentary sediment budgets so that resource managers can establish a framework for the evaluation of risks to downstream aquatic resources from the release of impounded clean sediments.

Effective operational management of a watershed requires the integration of real-time information about current conditions in the watershed with decision support tools that can reliably forecast the expected behavior of the watershed and evaluate the impact of operational decisions, such as alternative gate operations, in advance. A state-of the-art real-time watershed management system for the Big Cypress Basin, Florida is presented. This region has a unique hydrological regime, with close connection between surface water and groundwater and a complex managed drainage network with many structures. Novel aspects of this system include state-of-the art data assimilation methods to improve forecast accuracy and the use of fully distributed and integrated modeling to represent the close interaction between surface water and ground water. Performance results are presented for Tropical Storm Fay in 2008. This represents a major step towards the comprehensive real-time operational management of water resources and water quality within a watershed.

The main objective of the study was to suggest corrective measures for improving the productivity of the wetland eco-system. The specific objectives of the study was to utilize RS and GIS technologies to map the natural drainage course in the wetland and its catchments area in addition to preparing geo-morphological and ground water prospective map to explore and utilize the sub-surface water potential for irrigation. Second, to prepare detailed land-use/land-cover maps on 1:25000 scale and infer the availability of natural resources. Third, to prepare an optimum land use plan on 1:25000 scale, delineation and prioritization of the twenty micro watersheds of the entire catchments area of the wetland from soil erosion perspective. The total watershed area contributing water to the wetland system is about 25561 ha. The core waterlogged area of the wetland ecosystem having an area of 1750 ha (6.84 %) covering five revenue villages. Three basic themes of land-use/land cover, geomorphology and drainage and slope & watershed prioritization had been prepared. Based on the weighted parameters of SBI, NDVI, slope and other watershed characteristics, twenty micro watersheds were analyzed which falls in the study area. This micro watersheds had been categorized as low priority (6390.75 ha), medium priority (2407.66 ha), high priority (4372.34 ha) and very high priority (12390.25 ha) area. Considering the three field parameters such as slope, circularity ratio and drainage density as well as two remote sensing parameters such as NDVI and SBI, priority for treatment of each of the twenty micro-watersheds was assigned

The U.S. biofuel industry, namely the conversion of ethanol from corn, has increased the demand for corn as a result of government initiatives to increase alternative fuel productions to 35 billion gallons annually by 2017. Currently, a third of the corn crop grown nationally is used for ethanol production and this is expected to increase significantly in the foreseeable future. Growing corn traditionally requires high inputs of water and nutrients. The inevitable increase of environmental impacts resulting from increased corn production has been the focus of a US EPA-funded modeling study. The objective has been to identify the significant factors under various climate and management conditions that are most influential in controlling the environmental impacts. These factors can then serve as quantitative indicators to guide policy and management practices to minimize negative effects on the environment. This work focuses on the Upper Mississippi River Basin (UMRB), which is central to the nation's corn production. UMRB is one of the major sources of excess nutrient loadings into the Mississippi River and considered a leading contributor to the hypoxia problem in the Gulf of Mexico. The Soil and Water Assessment Tool (SWAT) model was applied to simulate the hydrologic and water quality impacts of increased corn production in the UMRB area. UMRB SWAT model sensitivity analyses were performed for a variety of different climate and management scenarios. The results indicate that changes in rainfall and temperature are the most influential factors for all hydrologic and nutrient outputs. When the management practice of removing corn stover (a process to yield more ethanol producing material) was incorporated in the model, it generally reduced the nutrient loss and increased erosion. Nutrient management practices did not produce large impacts or changes in nutrient loss at the basin scale.

Champions for water supply watershed protection in both Central and Northwestern Arkansas, the two largest and fastest growing population regions in the state, each led their communities to develop comprehensive watershed management strategies. Land use zoning is not used at the county level in Arkansas, and property rights are paramount in the state, both factors that challenge application of typical watershed management tools. Both planning efforts therefore relied heavily on stakeholder involvement and the development of watershed-based decision support tools to develop the foundation for management strategies. However, while Central Arkansas is working to implement a plan founded primarily in regulatory change, Northwestern Arkansas has chosen a voluntary adaptive management approach with several sustainable community themes. Both communities' newly developed watershed management frameworks position them well for responding to potential impacts of land use and climate change. This paper will describe and compare the frameworks, highlight how they represent the unique conditions for each community, and share lessons learned for other communities to consider.

Improved use of water resources in Afghanistan has become an important priority in U. S. Army operations. To further this, the Army Corps of Engineers, the U. S. Dept. of Agriculture, and the U. S. Geological Survey in conjunction with the U. S. Army's Task Force (TF)Yukon (4th Brigade Combat Team (Airborne), 25th Infantry Division) has undertaken a ground-breaking project to assess and prioritize numerous water resource improvement projects in SE Afghanistan. Conditions for completing traditional site-related review and planning are, to say the least, difficult. Our objective here was to identify and evaluate potential water resource projects in the southeast provinces using applied remote sensing science and technology. Sources of data included high-resolution satellite imagery, high-resolution elevation models, ground-truth from field personnel, existing spatial data and reports, and authors' experience in-country. Thousands of square kilometers were reviewed at scales up to 1:750 to identify and evaluate 295 potential water resource projects (storage dams, diversions, power generation, or upgrades to existing facilities, and watershed restoration). Each project was then prioritized using an industry-standard decision support model, integrating both engineering and watershed factors, such as sedimentation and stream system stability, cost indices, storage efficiency, benefiting agricultural lands, and environmental impacts. This study provided a systematic, detailed product to support field design, based on recognized expert evaluation. The report is now providing guidance to the Afghan ministries and coalition partners on developing water resource projects in a responsible and sustainable manner. In addition, the collected data are being used to scope potential water restoration projects and develop site plans. Utilizing remote sensing technology and expert personnel in this manner helped to maximize effectiveness of field investigation, sending ground personnel to only the most favorable sites for further evaluation, thereby reducing time on the ground in a difficult environment.

The Ohio River Basin is an ecologically-diverse hydrologic system covering 15 states and 528,357 square kilometers. The Ohio River contributes 60 percent of the flow in the Mississippi River at Cairo, IL. Over 2,600 incorporated communities and 548 counties administer various land use controls and programs for economic growth. The Corps' Ohio River Basin Comprehensive Reconnaissance Study identified numerous issues including aging public infrastructure with reliability concerns during extreme weather events, concerns for sufficient water supplies for at least 5 million people and optimum channel depths for the navigation industry - a $30 billion dollar industry along the Ohio River. Uncontrolled land cover change, deteriorating water quality, modified flows and lack of stormwater management pose significant threats to the ecology and economy of the region. Using a watershed approach, the Corps has recommended a series of planning actions that will address the issues of sustainability, reliability and resilience of water resources in the basin.

Historic flooding within the Iowa-Cedar River Basin, in 2008, has emphasized the need for an integrated approach to watershed-based planning and management of the basin. This paper provides a description of the emerging watershed study currently being developed by the Rock Island District, Corps of Engineers in cooperation with the state of Iowa, local governments, and private organizations. The purpose of the Corps planning study effort is to formulate a comprehensive watershed plan and process for interagency collaboration to address water resource and related land resource problems and opportunities in the Iowa — Cedar River Basin in the interests of increasing social and economic value, increasing ecological integrity, and managing future flood risk.

The key objective of this paper is to develop a mechanistic, 1-D hydrodynamic and sediment transport model namely, RILL 1D, that handles transcritical flows over abrupt changes and predicts changes in rill bed elevation, without violating the flow continuity equation. Replication of rill conditions necessitated the use of an enhanced TVD-MacCormack scheme with implementation of Tseng's surface gradient method, to provide an oscillation free solution over formed pool crests. The performance of the model is evaluated by comparing its results with rill observations from a flume study with fixed bed geometry and two field investigations with mobile beds. It is shown that the enhanced TVD-MacCormack scheme approximates, satisfactorily, depth and velocity for a fixed bed rill with steps and pools, except near the pool headwalls where a backroller forms with negative velocities. With field data the code is tested for its ability to reproduce measured values of sediment transport rates. RILL 1D performs reasonably well in these simulations in terms of sediment prediction rates and faired adequately in terms of replicating rill bed morphology. A sensitivity analysis is performed to assess the effects of cell size and critical erosional strength in the predictive ability of the model.

For the past few years, the U.S. Army Corps of Engineers' Institute for Water Resources, Hydrologic Engineering Center (CEIWR-HEC) has been developing the Watershed Analysis Tool (HEC-WAT). This software was created to help Project Delivery Teams (PDT's) conduct watershed and water resources studies in an integrated, comprehensive and systems based analyses. The degree of coordination across disciplines, offices and agencies, for these complex studies is often difficult to complete. The PDT must come to a consensus on the definition of the problems, issues, and opportunities and continue with the definition of the various models, events and analyses to determine impacts so that appropriate decisions may be made. This paper will discuss the development, features and capabilities of HEC-WAT and will also document several applications. In addition, a new feature will be discussed that will eventually allow HEC-WAT to run a Monte Carlo analyses so that a robust risk analysis can be performed.

Surface microtopography plays an important role in overland flow generation and soil erosion processes. Characterization of surface depressions and delineation of the entire watershed are critical to watershed modeling and management. In most hydrologic models, however, surface depression storage is estimated indirectly and inputted as a known value. In addition, it is often assumed that overland flow initiates after all surface depressions are fully filled. In reality, surface microtopography may control overland flow generation, surface runoff, soil erosion, and other hydrologic processes in a dynamic manner. The role of depressions that have various spatial scales and distribution characteristics is far beyond the functions of storing and detaining/retaining surface runoff. In this study, an improved surface delineation method was proposed to identify surface depressions and their relationships, precisely quantify the surface microtopography, and compute the maximum depression storage based on high-resolution DEM data obtained by using an instantaneous-profile laser scanner. Furthermore, a user-friendly, Windows-based software package was developed to facilitate the associated computations and visualization. The delineation method and the related software were tested using various scale DEM data. It is demonstrated that the new delineation approach is effective and efficient.

The Ensemble Kalman Filter (EnKF), a popular data assimilation technique for non-linear systems was applied to the Root Zone Water Quality Model. Measured soil moisture data at four different depths (5cm, 20cm, 40cm and 60cm) from two agricultural fields (AS1 and AS2) in northeastern Indiana were used for assimilation and validation purposes. Through daily update, the EnKF improved all statistical results (correlation coefficient and Root Mean Square Error and Mean Bias Error) compared to the direct insertion method and model results without assimilation for 5cm and 20cm depth. Soil moisture estimates for deeper layers (40cm and 60cm) did not show significant improvement from assimilating surface soil moisture depending on the initial soil moisture simulation results. It is also demonstrated that update intervals longer than three or four days do not improve the statistical results significantly. In addition, various ensemble sizes make little difference in the results for the upper layers.

The United States Department of Agriculture (USDA), Natural Resources Conservation Service (NRCS) publication Earth Dams and Reservoirs TR-60 (2005) describes design procedures and provides requirements for planning and designing earth dams and associated spillways. For high hazard dams, TR-60 specifies the probable maximum precipitation (PMP) event be used to generate the freeboard hydrograph (FBH) storm. TR-60 requirements may not be suitable for sites where physical site constraints may preclude construction or rehabilitation of a high hazard dam with the capacity to pass the PMP generated FBH. For these situations, TR-60 permits the use of an inflow design flood (IDF) analysis to determine the FBH design storm based on an event smaller than the PMP. IDF analysis is described in the Federal Emergency Management Agency (FEMA) Publication 94, Federal Guidelines for Dam Safety — Selecting and Accommodating Inflow Design Floods (FEMA 2004). This paper provides suggestions to aid the modeler in making an IDF analysis consistent with NRCS policies, addresses the considerations that should be given to using an IDF approach, and suggests appropriate documentation.

In this study, a 1-D Ensemble Kalman Filter (EnKF) has been used to update the soil moisture states of the Soil and Water Assessment Tool (SWAT) model predictions. Experiments were conducted for the Cobb Creek Watershed in southeastern Oklahoma for 2006–2008. Assimilation of in situ data proved limited success in the top layers only, due to the weak surface and root-zone coupling of SWAT. Negative impact on stream flow and especially storm-scale runoff result from degraded deep-layer soil moisture prediction. This indicates that although the model is calibrated for stream flow, the parameters are not tuned to represent the realistic physical coupling of the system. Therefore the improved surface soil moisture failed to produce better runoff and flow estimates. Synthetic twin study proved the potential of assimilating remotely sensed surface soil moisture in improving SWAT's hydrologic predictions (root-zone soil moisture, evapotranpiration, surface runoff and stream flow) with EnKF. However, perturbations used to generate ensemble trajectories could result in systematic biases in model states and degradation of certain variables that cannot be corrected with EnKF. The mechanisms causing such biases and the methods to correct them need to be further investigated.

Predictions from complex watershed models are relied on by policy-makers for resource allocations and development decisions. However, most managers do not have access to effective and practical approaches to represent the uncertainty within these systems and within the complex models; nor can they readily incorporate uncertainty into the decision process. In previous studies, Latin Hypercube Sampling combined with generalized likelihood uncertainty estimation (LHS/GLUE) and optimization was utilized to find reliable load allocations for the watershed of Moore's Creek, Virginia, given parameter uncertainty and uncertainty in the initial loads of fecal coliform bacteria. Although this approach increased load allocation reliability, as compared to a margin-of-safety method, the uncertainty analysis was computationally intensive and research intensive. In light of this rigorous nature, there is concern that many managers and community-based modelers will rely on simpler, less accurate approaches. New methods of uncertainty analysis have been developed that could significantly reduce the amount of computational effort required. This study integrates two methods of uncertainty analysis, LHS/GLUE and Dynamically Dimensioned Search, with the HSPF model and evaluates their performance on the Moore's Creek case study. The purpose of this paper is to present a methodology for comparing computational efficiency, ease of implementation, and accuracy of results. Results from this study will be presented at the conference and will help guide selection of an efficient choice of uncertainty analysis for use by managers and community modeling projects.

Component-based modeling offers an attractive approach for constructing next generation watershed models. In component-based modeling, a complex system is represented as a series of loosely-integrated components with defined interfaces and data exchanges. Because components are loosely-integrated, it is possible for modelers to change how components are linked together within a "plug-and-play" environment. Component-based modeling is attractive for modeling watershed systems because watersheds are complex systems, and modeling such systems often requires the integration of data and models created and maintained by different groups. Component-based modeling allows for the integration of these disparate data and model resources, while still allowing each group to maintain and advance their own parts of the overall system. Although the component-based paradigm has been used to construct many software systems, it has only recently been applied for modeling watershed systems. Thus, in order to leverage this approach for modeling watersheds, important questions must first be addressed such as how watersheds should be decomposed into system components. In this paper we begin with a vision for component-based modeling, then focus on an experiment that seeks to understand how boundary condition data are exchanged between fully-coupled model components, and finally discuss future work needed to advance the use of component-based modeling of watershed systems.

The burgeoning human growth, climate change and its variability are putting stress on our finite water resources. To ensure an adequate supply and quality of water for present and future needs under these critical conditions, it is necessary to understand the effects and consequences of the anthropogenic activities and natural variability on these resources. Beacon Institute for Rivers and Estuaries (BIRE) in collaboration with Clarkson University and IBM Corporation are in the stage of implementing River and Estuary Observation Network (REON) that will collect wide varieties of physical, chemical and biological parameters via an integrated network of sensors, robotics and computational technology distributed throughout the Hudson River in New York. Data collected from this large network will help to understand the important processes controlling water quality of the river. These large and diverse datasets are managed through the developed database schema in this study for easy discovery, access and dissemination to the broader user communities. Our developed database is capable to handle both point and gridded observations such as surface current maps captured by the high frequency (HF) radar system. The observational datasets are also stored with the metadata such as location and unit of measurements, calibration coefficients, data qualifying comments, etc. which facilitate easy interpretation of the stored datasets. This database will be interfaced with the point observation data model (ODM) developed by the Consortium of Universities for the Advancement of Hydrologic Science (CUAHSI), Inc. and thereby, will facilitate interoperability of our data model and will provide greater access to the broader user communities. In addition, the developed data visualization software in this study queries the data into the database and publishes simple color-coded contour plots of measured data for a specified time (e.g., the last 24 hrs, last 7 days, or last 30 days of measurement) on the static Web pages of BIRE's Web portal. This simple illustration of measured data in near real time will make general public aware of the environmental conditions and thereby, promote their participations in implementing policies in conserving our natural water resources.

The Morro Bay estuary, located on the central Coast of California approximately half way between Los Angeles and San Francisco, is one of the most important wetlands on the west Coast as it supports wide variety of habitats including numerous sensitive and endangered plant and animal species. Various studies have identified accelerated erosion and subsequent sedimentation as a major threat for sustainability of the bay. Watershed disturbances caused by agricultural activities are believed to be one of the major causes of the accelerated erosion and sedimentation. More than 200 conservation practices have been installed in the watershed since the mid-1990 to reduce erosion and sedimentation. This paper will review the implemented BMPs and will evaluate effectiveness of the BMPs using observations and modeling exercise. Streamflow and sediment concentration, measured mainly during the rainy seasons, are available for multiple locations in the watershed. However, the observations are not sufficient in terms of spatial density and data length to evaluate effectiveness of the mitigation measures at various locations in the watershed. It would be daunting in terms of cost to develop an intensive network of monitoring sites that would be needed for reliable management of NPS pollutants. As a result, comprehensive watershed simulation models that integrate watershed and climate characteristics and can estimate pollutant quantity at various locations, and that can also identify source of the contaminants, is emerging as a key component of watershed management. In this regard, a comprehensive watershed simulation model for the Morro Bay watershed has been developed using Soil and Water Assessment Tool (SWAT) to simulate both streamflow and sediment concentration. The observed data was used to improve prediction accuracy of the SWAT model through parameter sensitivity analysis and calibration steps. Parameter sensitivity analysis was performed using step-wise-regression analysis and Morris's one-at-a time (OAT) method. Calibration was performed using four different optimization methods: PEST, Genetic Algorithms, the Shuffled Complex Evolution Algorithm, and Dynamically Dimensioned Search. Relative performance of the sensitivity analysis methods and the calibration algorithms will be discussed in terms of effectiveness and computational efficiency. The developed model was used to evaluate effectiveness of the BMPs implemented in the Morro Bay watershed, and can also be used to prioritize sites where BMPs may be implemented in the future to further improve ecological integrity of the estuary.

This research investigates the storm-event based efficiency of grassed waterways (GWWs) in reducing sediment yield via a calibrated Water Erosion Prediction Project (WEPP) Model. The study site is an agricultural Iowa watershed (2600 ha), namely the South Amana Watershed (SAW). Results of this study showed that the GWWs reduced sediment yield within the SAW 3.5–59% during the simulated storm events. Furthermore, a strong correlation between event-based rainfall totals and associated sediment yield reductions were observed. GWWs were found to be more efficient for smaller storm events. Finally, to investigate the effect of the drainage area size and the gradient of the surrounding landscape on the efficiency of GWWs, a small representative concave hillslope (15 ha) was also modeled with the calibrated WEPP. GWWs reduced sediment yield more efficiently when the contributing hillslopes had lower gradients. A threshold gradient of ∼3 % was observed beyond which the GWW efficiency was independent of the steepness of the surrounding topography. Overall, the GWW efficiency for the 15 ha drainage area was higher compared to the one for the SAW and ranged between 10–81%.

The accurate assessment of flood risk and flood damages, as well as the sizing and design of flood control projects in any watershed, relies on the peak flood discharges, the peak flood stages, and the maximum runoff volumes generated for that watershed. Peak discharges, stages, and runoff volumes can be determined through application of rainfall runoff and hydraulic methodologies that utilize "critical" design rainfall events (volume, duration, and temporal distribution) to generate runoff hydrographs from design rainfall events. FEMA guidance states that the critical storm is a design storm which provides the highest flood discharges/water surface elevations for the flooding source. In practice, it is often assumed that the 100-year, 24-hour duration storm produces the critical or highest flood discharges, stages, and runoff volumes throughout the watershed. However, the actual critical duration design storm may be something other than the 24-hour design event, and there may be more than one critical duration storm that produces critical flood discharges, stages, and storage volumes across the watershed. A critical duration analysis is required to estimate representative peak discharges and flood stages and to properly size flood control projects. A critical duration analysis can be performed to determine the critical duration storm specific to each watershed ^and each study reach across the watershed. Typically, flood discharges and stages for the 1-, 3-, 6-, 12-, 24- and 48-hour storm durations for the 100-year frequency event are generated to identify the critical duration which produces the highest peak flows and stages for all study locations within the watershed. Performing this analysis and using the resulting critical duration events helps to ensure that the hydrologic/hydraulic models produce the highest flood discharges and stages across the watershed. Stormwater management planning conducted for the Little Calumet River Watershed in Chicago, Illinois, by the Metropolitan Water Reclamation District of Greater Chicago (MWRDGC), provided the opportunity to assess the impacts of critical duration analyses on establishing 100-year peak flows, defining floodplain boundaries, and sizing flood control facilities. Two 20+ square mile watersheds from this effort will be presented. This paper will present an overview of the critical duration analysis procedure and will demonstrate the importance of proper selection of the critical duration event by assessing the impact of critical duration on peak flows and the sizing of regional flood management facilities in two sub-watersheds.

An evaluation and provisional re-calibration of a set of regional Hydrologic Simulation Program — FORTRAN (HSPF) snow modeling parameter values used by the U.S. Army Corps of Engineers in the Chicago, Illinois, region were carried out for two small gaged urban watersheds in the region using data from water years 1996–2007. The simulated snow fluxes (snowfall, sublimation, and melt) and storage (snowpack) were evaluated by comparison with daily observed snowfall and snowpack-depth data from two National Weather Service (NWS) Cooperative (Coop) observer stations and output from NWS-NOHRSC's Snow Data Assimilation System (SNODAS). HSPF snow parameter sensitivities and provisional re-calibration were performed using the Model Independent Parameter Estimation Routine (PEST) calibration program. It was observed that for the period of available SNODAS data (water years 2004–7), using the original snow parameter values, the HSPF-simulated cumulative snowfall snow-water equivalent (SWE) exceeded both the corresponding SNODAS and NWS Coop values by 20–40%. The HSPF-simulated cumulative snowmelt exceeded the corresponding SNODAS value by a similar amount. However, the HSPF-simulated cumulative snowpack depth values were significantly smaller than both the NWS Coop and SNODAS values, suggesting that the HSPF-simulated snowpack has too small a residence time. In support of this observation, the HSPF-simulated discharge in the winter months in these watersheds tends to be too early, with simulated flows too large in mid-winter and too small in the early spring compared to observed flows. This result shows the potential usefulness, despite their limitations, of the combined NWS Coop and SNODAS data for guiding the simulation of snow-related processes. In addition, the provisional re-calibration of the snow parameter values for these watersheds using PEST was able to improve this discharge timing problem, thus showing PEST's potential for providing improved simulation of HSPF snow processes.

Flash flooding in a mountainous region of the Kingdom of Jordan, near the Red Sea, produces quick-response, high-volume and peak flow floods that have caused extensive property damage and loss of life. In February 2006, the combination of high relief and extreme climate aridity resulted in flash flood conditions that caused five fatalities and extensive damage to infrastructure. The flooding disrupted power and water supplies and damaged the wastewater treatment plant, causing significant environmental degradation and substantial hardship for the people in the town of Aqaba, Jordan's only shipping port. The port is crucial to the Jordanian economy and protection of the city from flood damage is critical to maintaining development and public safety. Recognizing the need to protect existing and future infrastructure, a flood hazard mitigation plan was developed for the Aqaba Special Economic Zone Authority of Aqaba, Jordan, through a grant from the United States Agency for International Development (USAID). This comprehensive study included a hydrologic analysis to predict peak flows and hydrographs. The hydrology methodology utilized available geographic information system (GIS) tools to automate the generation of data needed for development of a hydrologic model. Peak flow and hydrograph predictions were used as input for hydraulic, sediment transport, and flood hazard mitigation alternative analyses. This paper describes the data acquisition and methodology used to develop hydrologic characteristics and presents the hydrologic model used to simulate runoff hydrographs resulting from the design storm rainfall.

Floods, especially flash floods, have killed many people in Sana'a in the past years. The urban development of Sana'a, the capital of Yemen, has led to an increase in flood hazards due to rapid changes in existing landuse to impervious surfaces and the presence of increased population and buildings in flood prone areas. A comprehensive hydrologic analysis of the Sana'a Basin was conducted using GIS for pre- and post-processing of large datasets, HEC-SSP for rainfall frequency analysis and HEC-HMS for hydrologic modeling. This analysis identified the basin characteristics, estimated rainfall distributions, depth, and frequencies, and developed flows for different storm frequency events to be used in hydraulic modeling and floodplain mapping of Sana'a floods. Significant challenges were addressed during the modeling process including: limited historical flood data, short historical rainfall records, non-standard hydrologic input data, poorly understood local hydrology, and major changes in the landuse from rapid urbanization. Based on the results of the hydrologic analysis and further hydraulic modeling, the floodplains were effectively mapped along Sana'a major stormwater channel and the Sana'a flood hazard areas were identified for extreme storm events. This information is being used to support a natural disaster risk evaluation for Sana'a.

A case study is presented in which the impact of using spatially distributed, radar indicated, rainfall for lumped-distributed rainfall runoff modeling is demonstrated. The calibrated model was used to prioritize siting of runoff detention devices to minimize flood flows and sediment erosion in North Fish Creek, Bayfield County, WI. Modeling for the study demonstrated the importance of using bias adjusted, radar indicated rainfall for calibration. A HEC-HMS model with 97 sub-basins with 1km² average area was calibrated to a full summer of continuous simulation that included two floods of historic magnitude. The model employs explicit soil moisture accounting, kinematic wave overland flow, and Muskingum-Cunge channel routing. The Preistly-Taylor technique was used to estimate evapotranspiration with solar radiation, temperature, and a crop coefficient to track soil moisture losses in continuous simulation. A suite of distributed parameters were developed, using satellite derived, land cover, SSURGO soils data, checked with field sampling, and digital elevation data interpolated from 1:24K topographic maps. Radar rainfall estimates were derived using NEXRAD level III data at a spatial resolution of roughly 500m. These data were smoothed and sampled to a 10m grid in order to better represent rainfall gradients. It was also bias corrected to match the cumulative rainfall observed by a USGS rain gage at the modeled watershed outlet. To examine the impact of using spatially and temporally distributed rainfall, three scenarios are presented and compared. First, the radar indicated precipitation for each of the 97 sub-basins is applied. Second, the mean radar indicated precipitation is applied to the entire watershed, using the time distribution from the rain gage. Finally, the rain gage indicated rainfall is applied uniformly over the watershed. The scenarios are compared, based upon the measured hydrographs at the stream gage.

There are well-known, substantial concerns that peoples' uses of water may significantly alter the quantity and quality of water-cycle processes at the local and regional scales. Addressing these concerns requires a substantially better understanding of the linkages and feedback between the various systems than presently is available. Although many studies have examined human-water dynamics, the complexity of such coupled systems is not well understood as, among other causes, the data and tools for multidisciplinary natural scale studies are not available yet. The recent information and communication technology advancements, collectively labeled as informatics (or hydroinformatics for the water-related domain), enable to address a new class of problems around the organization of data and information leading to knowledge extraction. Hydroinformatics embraces not only methods of data capture, storage, processing, analysis and graphical display, but the use of advanced modeling, optimization, knowledge-based tools and computational infrastructure (cyberinfrastructure). This paper discusses the initiation of the cyberinfrastructure-based Upper Mississippi River Basin Observatory (UMRBO). The observatory would consist of a number of interdisciplinary, multi-institutional teams synergistically collaborating on a series of research sites at different locations within the basin. There is no existing recipe to establishing an observatory at this time, however, there is a vast amount of experience and knowledge that can be shared to help establish an observatory. Building an observatory should be a collaborative, inclusive and equitable process and could be used to establish a practical problem solving agenda linking the abundance of research carried out in the Upper Mississippi River Basin to the needs of mission agencies and stakeholders within the basin. In order to begin the process, a workshop was held, in which an international team of research scientists and practitioners came together to discuss how the process could become a reality.

Innovation in traditional watershed modeling methods are necessary to address ever evolving risk assessment strategies for floodplains. With warming climates, storm events in coastal areas such as Florida are becoming more prevalent in frequency and intensity. This requires more sophisticated estimation of hydrological parameters used for calculating rainfall excess associated with storm events. Rapid transition in land uses that come with development also require a flexible approach to estimating rainfall excess which can then be responsive to changes in land cover characteristics. The authors have applied active percolation in modeling in a watershed project with significant areas of Type A hydrological group soils. Results indicate that models utilizing more physical based rainfall excess methods coupled with percolation in dry depressional areas and in dry retention pond systems results in a significant difference in floodplain extent where the soil conditions favor infiltration. These results are considered more reasonable and defensible, better reflecting observed conditions in these areas and more easily adaptable to future changes in land use.

KINEROS originated in the 1970's as a distributed event-based rainfall-runoff erosion model. A unique feature at that time was its interactive coupling of a finite difference approximation of the kinematic overland flow equations to the Smith-Parlange infiltration model. Development and improvement of KINEROS has continued for a variety of projects and purposes. As a result, a suite of KINEROS2-based modeling tools has been developed that can be executed from a single shell. The tools range from the event-based KINEROS2 flash-flood forecasting tool to the continuous KINEROS2-Opus2 (K2-O2) biogeochemistry tool. The KINEROS2 flash flood forecasting tool is being tested with the National Weather Service (NWS). It assimilates the NWS Digital Hybrid Reflectivity (DHR) radar product in near-real time and can simultaneously run ensembles using multiple radar-reflectivity relationships. In addition to simulation of runoff and sediment transport, K2-O2 can simulate common agricultural management practices, plant growth, nutrient cycling (nitrogen, phosphorus and carbon), water quality and chemical runoff. Like any detailed, distributed watershed modeling software, the KINEROS2 suite of tools often requires considerable effort to implement; it is necessary to delineate watersheds, discretize them into modeling elements, and parameterize these elements. This need motivated the development of the Automated Geospatial Watershed Assessment (AGWA) tool. This ArcGIS-based tool uses commonly available, national GIS data layers to fully parameterize, execute, and visualize results from both the SWAT and KINEROS2 models. By employing these two models AGWA can conduct hydrologic modeling and watershed assessments at multiple temporal and spatial scales. A variety of new capabilities have been added to AGWA to configure KINEROS2 inputs to simulate a number of land-management practices or changes (fire, urbanization, and best management practices) as well as incorporate decision-management tools for rangelands. An overview of these tools will be provided.

Adequate supplies of high quality water are essential both for economic development and basic human survival. As populations continue to rise, municipal supplies, irrigation, power supply, resource extraction, industrial development, recreation, ecological services, and waste disposal will continue to place significant, often conflicting, demands on limited water resources within a region. Increasing scarcity leads to conflicts as existing frameworks for apportioning resources, or lack thereof, cease to function properly such that stakeholder needs are no longer met. Similarly, excessive supplies can result in conflict as well due to flood damage or complaints of water being "wasted" as large volumes flow downstream. Because water is closely connected with our livelihoods, quality of life, and values, water resource disputes can be bitter and seem intractable. Effective management of water resources requires the use of robust, scientifically defensible methods along with collaboration and support of multiple parties to build support for policies or projects. Systems models, which are designed to model a water supply system using hydrologic data and realistic operating rules, can be a tool for achieving these goals. This presentation describes an innovative modeling framework for assisting utilities, regulators, and other watershed stakeholders in developing solutions to complex, multi-objective water management issues and presents a number of applications used in real-world projects to resolve difficult watershed issues.

Hydromodification is caused by anthropogenic activities driven by human population growth and resource consumption that alter watershed hydrologic responses. These activities include urbanization, channel modification, flow regulation by water impoundments, water withdrawal, and climate change. Hydromodification is a major source of integrated stressors that disrupt ecosystem functions and consequently the ecosystem services that watersheds provide. Stressors associated with hydromodification include flow alteration, water quality degradation, habitat degradation, and loss of aquatic life and biodiversity. Hydromodification is one of the leading sources of water quality impairment. Under the Clean Water Act, it is a regulatory requirement to develop total daily maximum loads (TMDLs) for streams and rivers affected by hydromodification. However, modeling approaches that address the complexities of hydromodification are not well established. Specifically, quantifying stressor levels associated with different hydromodification activities and assessing their impacts on aquatic ecosystems is a major challenge. In this paper, we propose Better Assessment Science Integrating Point and Nonpoint Sources (BASINS) as a modeling framework suitable for forecasting anthropogenic-induced stressors and their effects on aquatic ecosystems.

Thermal impacts on streams due to changes in land use can have dramatic effects on aquatic life, especially on cold-water species like trout. Summer thunderstorms coupled with mid-summer low flow conditions and urbanization can raise temperatures and the risk of cold-water fish and macroinvertebrate mortality. A series of spatial models was developed in the Vermillion River trout stream watershed to understand the impacts of land use change on runoff and stream temperature. Simulated full development in upstream subwatersheds increased stream temperature slightly several miles downstream, but increased it 3.8°C in small tributaries. Downstream mitigation of thermal impacts was found to be ineffective, because much of the upstream thermal impact was already lost by atmospheric heat transfer and dilution by the time the flow entered the downstream reaches. In conclusion, thermal mitigation in the Vermillion trout stream watershed should take place near the impact source, and shading should be employed as a general trout stream management strategy.

Sediment yield and transport capabilities have recently been added the Hydrologic Engineering Center's (HEC) Hydrologic Modeling System (HEC-HMS) and River Analysis System (HEC-RAS). HEC-HMS computes watershed sediment yield using the Modified Universal Soil Loss Equation (MUSLE) and includes several empirical assumptions that translate a total event load into a sediment time-series by grain class. Multiple methods for modeling sediment transport and erosion/deposition within the channel are available as well. HEC-HMS sediment output can provide sediment load boundary conditions for more detailed, mobile boundary, open channel, sediment routing simulations using the sediment transport module in HEC-RAS. This paper will cover the approaches and methodologies used in these sediment models and focus on the features and assumptions included to facilitate integrated watershed-riverine modeling with both programs.

Managing the impacts of future climate and land use change on hydrology and water quality should benefit from an improved understanding of watershed response to change. EPA ORD is evaluating the impacts of climate change and urbanization on hydrology and water quality in 20 major river basins throughout the United States. The approach involves application of dynamic watershed models, HSPF and SWAT, to simulate historical conditions and a range of potential climate and landuse changes scenarios. While most climate change impacts studies focus on hydrology, this unprecedented effort also evaluates nutrient and sediment impacts. Study results will improve our understanding of system sensitivity to climate and land-use change in different regions of the country, and provide a range of plausible scenarios of future hydrologic and water quality change that can be applied in various planning and scoping frameworks. By investigating a number of methodological issues, it will also provide guidance and a template for conducting similar studies in other regions of the United States and internationally. The first phase of the project involved selection of representative watersheds from across the country. Selection considered technical and programmatic concerns, such as variability in climate, precipitation extremes, watershed characteristics, ecosystem types, and settlement types, as well as proximity to large-scale monitoring studies, overlap with other EPA projects, and coverage of EPA regions. Subsequently, a detailed approach to configuring and executing the SWAT and HSPF models was conceived and tested. Because SWAT and HSPF models are both being used to simulate the initial set of watersheds, the approach was developed to optimize efficiency in model configuration and to ensure consistency in assumptions. Lessons learned from previous climate change hydrology modeling studies resulted in particular emphasis on appropriate representation of hydro-meteorological factors, such as potential evapotranspiration. Model application for 5 pilot watersheds throughout the country comprises the second project phase. Pilot watersheds include the Minnesota, Apalachicola-Chattahoochee-Flint, Susquehanna, Willamette, and Salt/Green/San Pedro. HSPF and SWAT models of the pilot watersheds have been calibrated and validated for an extended time period to most accurately represent hydrologic regimes and water quality conditions. Meteorological datasets representing a suite of potential climate change scenarios for the period 2040–2070 have been developed using statistics derived from the North American Regional Climate Change Assessment Program (NARCCAP), the Bureau of Reclamation,and tools such as the BASINS Climate Assessment Tool (CAT) and the SWAT Weather Generator. These datasets are being combined with scenarios of future land-use change (residential and urban) developed by EPA. Taken together, all of these scenarios provide a basis for evaluation of climate change alone, land use change alone, and combined effects of climate and land use change. The third and final phase will consist of simulations in the remaining 15 non-pilot basins but using only one of the watershed models. A range of hydrologic and water quality endpoints are being determined for each simulation. Endpoints include mean monthly and mean annual stream flow, flood events, low flow events, the date of annual runoff center of mass, and mean monthly and mean annual nitrogen, phosphorus, and sediment loads. Additional endpoints will be identified and evaluated to fully inform upon a range of stream flow, water quality, aquatic ecosystem, and EPA program management goals and targets. Comparisons will be made within watersheds and across watersheds to provide a comprehensive assessment of potential climate change implications.

Hydrology in the Southwestern USA is characterized by starkly different processes. Spring snowmelt is the primary source of water but hydrology is also characterized by summer monsoon rainfall. The management of scarce water resources is a continuous challenge. Solutions to this challenge can be assisted by mathematical models. The purpose of this paper is to provide information gathered from Southwestern field experiments conducted over a 10+ year period which may be useful in decision making. Based on hundreds of observations, the steady-state loss rates for the soils investigated ranged from 2 mm/hr to 93 mm/hr depending on factors such as initial soil moisture content and cover. Similarly, the Curve Numbers ranged from 48 to 97. Relationships were found between the loss rates and the CN values for the data set.

In recent years the National Weather Service (NWS) has developed new precipitation-frequency information for major areas in the USA. Accompanying this information the NWS has presented temporal precipitation distribution curves for 6, 12, 14 and 96-hour durations. Engineers need to incorporate the latest NWS data into watershed models and need to understand how the selection of a temporal precipitation distribution can affect model results. This is particularly critical in arid and semi-arid watersheds where short duration precipitation has a large influence on peak flow rates. Some alternative methods of applying temporal distributions include use of a national or regional standardized distribution, a distribution curve obtained directly from the NWS studies, a distribution computed from storm frequency data with an assumed peak intensity position, and a distribution based on combining NWS distribution curves with storm frequency data. Selection of an appropriate temporal distribution will depend on watershed conditions.

This paper summarizes the development and evaluation of erosion control and flood control projects to support the Calumet-Sag Detailed Watershed Plan (DWP) for the Metropolitan Water Reclamation District of Greater Chicago (the District). The 151 square-mile Calumet-Sag Watershed, located in the southwestern part of Cook County, is one of six major watersheds within the county. In 2004, the District was granted regional stormwater management authority through State Legislation. The six DWPs developed by the District are intended to identify projects to address regional stormwater problems. The objective of the DWP was to supply the District with information on existing conditions, stormwater problems, alternative improvements considered to address stormwater problems, and other information necessary to prioritize alternative improvement projects. An integrated watershed management approach, combining extensive community involvement, as well as hydrologic and hydraulic (H&H) modeling, inundation mapping, and damage assessment was applied to develop and analyze potential projects. To evaluate stormwater problems and potential projects, H&H models were developed and calibrated to USGS and observed data. The fully dynamic unsteady flow modeling approach was used to account for significant in-channel storage due to a relatively flat watershed. H&H models were then used to assess the risk of flooding for various recurrence interval storms. Property damages due to flooding were estimated using a methodology consistent with the U.S. Army Corps of Engineers Flood Damage Assessment program. Estimated flood damage was considered in combination with the probability of event occurrence. A Python script was developed to automate the batch geoprocessing of inundation areas with GeoRAS water surface elevation TINS to efficiently support damage estimation. Erosion damages were assessed for structures or infrastructure at risk of loss due to actively eroding stream banks. Stormwater improvement alternatives were developed at a conceptual level to address regional stormwater problems. Benefits were calculated for each project as the difference between existing and alternative conditions damages. Conceptual level cost estimates were produced and included design, construction, and maintenance costs. An innovative web-based database was developed to facilitate consistent calculation methodology and data management of damages, benefits, and cost estimates for alternatives evaluated for all six DWPs. A benefit-to-cost (B/C) ratio was developed for each alternative. In addition to the B/C ratio, features such as water-quality impact, number of structures protected, and the impact on wetland and riparian area were noted for each alternative. Alternatives were recommended based upon consideration of their ability to reduce regional stormwater damages. The District's Board of Commissioners will prioritize the implementation of recommended stormwater improvement projects.

This paper describes how hydrologic information was recently updated to represent current flooding conditions within the Little Calumet River watershed in Northeastern Illinois. The Metropolitan Water Reclamation District of Greater Chicago (District) is currently developing a Detailed Watershed Plan (DWP) for the Little Calumet River Watershed in Cook County, Illinois. The objective of the DWP is to identify regional stormwater related concerns and develop alternative solutions to address those concerns. The District is coordinating the planning effort with the Little Calumet River Watershed Planning Council (WPC). This presentation includes an overview of the objectives of the planning effort and a detailed description of the hydrologic and hydraulic modeling performed. The planning process consisted of several steps, including gathering information on current watershed conditions; analyzing the suitability of existing information; obtaining required new data; developing detailed hydraulic and hydrologic models of the watershed; identifying potential projects to address stormwater related concerns, such as flooding and water quality; quantifying benefits; and estimating the costs of potential improvement projects. The HEC-HMS model was used in the hydrologic evaluation of actual storms and design storms. To provide for the most representative conditions, Illinois State Water Survey Bulletin 70 frequency distributions were used. Watershed sub-basins were delineated using GIS and HEC-GEOHMS tools. A total of 540 sub-basins were delineated. Initially, the NRCS method was used for determining rainfall loss and unit hydrograph shape, but ultimately the Clark Unit Hydrograph method was chosen as more representative of the watershed area. The Muskingum-Cunge hydrologic routing method was used for sub-basins outside of Cook County, whereas the modified Puls channel routing and diversion was used to represent combined sewer areas. Detailed "unsteady flow" hydraulic modeling was performed with HEC-RAS due to unique characteristics of the Little Calumet River system, including complicated inter-basin flow situations. Comprehensive field survey work was performed to verify every structure and channel dimension within all tributaries, and only the most current existing modeling and supporting data were used to build a robust model. While several large, discrete storms were available and were used for calibration and verification, a storm event in mid September 2008 provided the storm of record for several areas within the watershed. Models were recalibrated to this event. Based upon the updated area hydrology and detailed hydraulic modeling, flooding inundation maps were generated from the models that showed several areas with increased predicted floodplains over existing DFIRM maps. The latest versions of HEC-RAS and HEC-HMS modeling tools were used in this effort. The calibrated and validated models were used to evaluate almost 200 individual flooding issues and develop a DWP that contains information on the watershed's areas of concern and a listing of potential regional capital improvement projects to address flooding concerns based upon benefit / cost analysis and other factors.

Lake Loiza and Lake La Plata are two impaired lakes located in Eastern Puerto Rico. Both lakes are impaired due to excessive phosphorus inputs from the surrounding watersheds with upstream river impairments due to fecal coliform. The goal of the Watershed Stewardship Program is to develop meaningful water quality improvement strategies for impaired waters in the Rio Grande de Loiza and Rio La Plata Watersheds tributary to and including Lakes Loiza and La Plata. Included in these location specific strategies is the identification of the water quality problems, identification of the sources of these problems, the development of water quality models to provide insight, and to develop remedies for these problems. During Phase 1 of the program, TMDLs were developed using the Loading Simulation Program in C++ (LSPC) model and existing data. The existing data were relatively sparse and unevenly distributed within the Loiza and La Plata watersheds. Phase 2 of the program involved identifying four small pilot subwatersheds that could be used to test the modeling assumptions of Phase 1 by collecting site specific data and developing Hydrologic Simulation Program — Fortran (HSPF) models for total phosphorus and fecal coliform. As LSPC and HSPF are "lumped parameter" models, they are useful for examining large scale watersheds and producing generalized results. Many of the large scale assumptions can break down when assessing smaller areas within the larger watershed. Overall the modeling analysis of the small subwatersheds verified the assumptions of the original TMDL analysis. However, certain loading assumptions, such as estimates of the percentage of failing septic systems, varied widely from one subwatershed to another. Management plans were also developed and implemented during Phase 2 of the Watershed Stewardship Program to improve water quality in each of the pilot subwatersheds based on the needs in each subwatershed. Post-implementation sampling is planned during 2010 to assess the effectiveness of the management plans. The intent is to use the pilot subwatershed management plans as a model for other watersheds within Puerto Rico.

An innovative approach was used to build a hydrologic model of the 230-square mile Vermillion River Watershed, Minnesota. The model was used to set peak flow standards at locations where the Vermillion River or one of its tributaries crosses a community boundary. XP-SWMM was chosen because it is well-suited to detailed modeling of urban watersheds — making the model "expandable" for more detailed assessments of local communities. A combination of ground truth and NEXRAD precipitation data were used to account for the spatial and temporal variability of rainfall. In order to build confidence in modeling results and facilitate stakeholder buy-in, the model was calibrated using seven stream flow gauges located throughout the watershed. PEST, a parameter estimation software package, was used to automate calibration of hydrologic parameters.

The Catskill District of New York City's West-of-Hudson water supply system is one of three major reservoir systems that supply water to New York City and includes Schoharie Reservoir, Shandaken Tunnel, and Ashokan Reservoir. Approximately 40% of the City's average demand is provided by the Catskill System, with an average of 50% and 10% provided by the Delaware and Croton Systems, respectively. The New York City Water Supply System (Figure 1) is operated by the New York City Department of Environmental Protection (NYCDEP) to provide more than 1.1 billion gallons per day of water to more than 9 million customers in the City and the surrounding communities. In the Catskill System, Schoharie Reservoir is fed by a 314-square mile watershed, and diverts up to 615 mgd to Esopus Creek via the Shandaken Tunnel. Esopus Creek drains a watershed of 200 square miles, and flows into Ashokan Reservoir. Water from Ashokan Reservoir is conveyed via the roughly 600-mgd Catskill Aqueduct to Kensico Reservoir, where it mixes with water from the Delaware System before disinfection and delivery to NYC. NYC has maintained a continuous waiver from the federal filtration requirements for its Catskill and Delaware surface water supplies since 1993. In 2002 and 2007, the US EPA issued Filtration Avoidance Determinations (FADs) that classify the Catskill and Delaware Systems as meeting the requirements for an unfiltered water supply given in the Surface Water Treatment Rule (SWTR) and the Interim Enhanced Surface Water Treatment Rule (IESWTR), contingent upon construction of a UV disinfection facility. Due to development in the Croton watershed, the Croton System was not eligible for filtration avoidance; construction is underway on a filtration plant to treat Croton water. Despite the typically pristine nature of the West-of-Hudson supplies, the Catskill System is subject to occasional periods of elevated turbidity levels following major storm events. NYCDEP developed the water supply — water quality modeling framework presented here in order to evaluate alternatives for controlling turbidity in the Catskill reservoirs. This paper describes the development of this modeling tool and its application to Catskill turbidity control issues.