Bridging the Gap: Meeting the World's Water and Environmental Resources Challenges

The discovery by the Kansas Department of Health and Environment (KDHE) and the United States Environmental Protection Agency (EPA) that polyvinyl chloride (PVC) pipe used in distribution systems could leach the vinyl chloride monomer and contaminate the drinking water delivered to customers was largely accidental. Doniphan County, Kansas Rural Water District No. 5 (hereafter referred to as Doniphan # 5), like many rural water districts, was formed in the late 1960s when the United States Department of Agriculture Farmers Home Administration (FHA) financed regional water systems to connect small public drinking water supplies and private wells into a more regional system to serve rural America. In addition to providing drinking water to more than 1,400 people, Doniphan No. 5 sells water to a smaller water district, Doniphan County Rural Water District # 2 in northeast Kansas. Doniphan # 5 had been testing for VOCs since 1985. These samples are taken, as required by the regulations, at entry points to the distribution system. These entry points in rural water systems are wells, clusters of wells, water imported from another supply or from a treatment plant. There were no detects in the official VOC testing done under state and EPA regulations for Doniphan # 5.

A new patented constructed wetlands treatment technology for enhanced nitrogen compound reduction has been developed recently by Tennessee Valley Authority. This new treatment is known as a reciprocating flow constructed wetland (RCW). This study compares the nitrogen reduction performance of a reciprocating wetland system to more traditional subsurface gravity flow wetlands in the same area of the country. Average ammonia reductions in the reciprocating systems were found to be almost double the gravity flow systems. Through two different statistical analyses, it was found that the reciprocation does have a significant effect on ammonia reduction in these systems. However nitrate concentrations may increase due to nitrification and, thus the claim of increased denitrification was not proven. These systems are successful in reducing nitrogen concentrations to below on-site effluent limitations in Alabama, but require more understanding of the basic nitrogen transformations taking place.

This paper presents the advantages and limitations of using a dispersion model to evaluate potential human exposures to asbestos in ambient air. In addition, this paper suggests an approach that uses a dispersion model coupled with the analysis of morbidity and mortality statistics to evaluate human exposures to asbestos in ambient air that may have occurred in the past.

Atrazine, the major s-triazine herbicide used for broadleaf weed control in the corn-belt of the mid-west United States, subsequently appears in drinking water supplies and has resulted in elevated levels of the herbicide in many drinking water supply impoundments. Higginsville, a rural community in north central Missouri, obtains its drinking water from an impoundment that collects agricultural runoff periodically containing elevated levels of s-triazines. In addition to in-plant treatment, in some situations, watershed management may be effectively implemented to control the release herbicides to water supplies. Parameters such as the features of watershed, farming practices, and impoundments that result in high levels of herbicides in the water supplies are needed for reliable control of atrazine through management practices. The objective of this research was to investigate the effects of watershed management, land-use, and environmental factors on atrazine transport in the Higginsville City Lake Watershed in Missouri.

The BASINS system was developed for the purpose of providing technical tools in support of EPA regulatory water quality programs. BASINS 3.0 does this by providing a range of detail in watershed models and by providing databases, data management tools, documentation, and other resources to make modeling waterbodies and watersheds easier. First released in 1996, the BASINS community has grown to over 3,000 U.S. and international users. BASINS 3.0 provides a range of watershed models from which watershed managers can select the one that best meets their needs with an appropriate level of model complexity, control scenario detail, uncertainty, and analysis cost. The three watershed models in BASINS 3.0 include: the complex Hydrological Simulation Program Fortran (HSPF) v12, and Soil and Water Assessment Tool (SWAT) models; and the simple PLOAD model. The development background as well as the functionality of each model will be described briefly in order to demonstrate their design purpose and relative modeling niche. A new system architecture, where each system function is packaged in a separate ArcView extension, will facilitate model/tool upgrades and system expansion.

Some of the highest losses of nitrate to surface waters come from drained agricultural land. Given previous this article studied for Belgian farming conditions (i) the effect of subsurface drainage density on nitrate losses and (ii) the economics of nitrate emissions, using the nitrogen version of DRAINMOD. DRAINMOD was used to simulate the performance of the drainage system of the Hooibeekhoeve experiment, situated in the sandy region of the Kempen (Belgium), and this for a 14-year (1985–1998) period. In the analysis a continuous cropping with maize was assumed. Daily NO₃-N losses were predicted for a range of drain spacings and depths, two drainage strategies (conventional and controlled) and three fertiliser application dressings (225, 275, 325 kg N ha^–1). Losses of N in subsurface drainage occur almost entirely in the NO₃-N form. Losses of organic and anorganic N in the form of NO₃-N in surface runoff are small and can be neglected. Hydrologic results indicated that increasing drain spacing or decreasing drain depth reduces drainage discharge while it increases runoff. The use of controlled drainage reduces subsurface drainage and increases runoff. Results also revealed that increasing the drain spacing or decreasing the drain depth reduces nitrate-nitrogen (NO₃-N) drainage losses and net mineralisation, while increasing denitrification and runoff losses. Controlled drainage caused a predicted reduction in drainage losses and an increase in denitrification and runoff losses. The optimal combination of drain density and management is one that maximise profits and minimise environmental impacts. Simulated results indicated that NO₃-N losses to the environment could be substantially reduced by reducing the drainage density below the level required for maximum profits based on grain sales. The study concluded that, if the environmental objective is of equal or greater importance than profits, the drainage systems can be designed and managed to reduce NO₃-N losses while still providing an acceptable profit.

This paper outlines the steps required in the designation process and the various financial and regulatory incentives that are available in the State of Florida's Brownfields Program. Florida's Brownfields Program was created to assist local governments and the person responsible for cleanup and redevelopment with the remediation and sustainable reuse of contaminated and abandoned or underused sites. The designation and redevelopment or reuse of a brownfield site involves community residents and community partnerships. The redevelopment and reuse process consists of identification, evaluation and prioritization of sites, remediation, and marketing and finally redevelopment of a site. Numerous state financial, regulatory and technical incentives exist for the redevelopment and sustainable reuse of "brownfield" sites. Local incentive options such as fee waivers, property tax abatements or exemptions, local matches for federal and state programs, and fee moratoriums are also available to local governments to further brownfields redevelopment and cleanup. State incentives include a loan trust fund, a loan guarantee program, a job bonus refund program, a 35% tax credit, a sales tax refund, and liability protection.

All human societies have rules, whether written or unwritten. Those rules, and the mechanisms to enforce them, evolve as a reflection of the society's values and cultures. In environmental management, however, units of ecosystem management, such as watersheds, seldom match political boundaries. When an ecosystem crosses state or national borders, therefore, the process of developing and enforcing rules becomes significantly more challenging. In 1909, the United States and Canada established the International Joint Commission under the terms of the Boundary Waters Treaty. The role of the IJC is to "to prevent disputes regarding the use of boundary waters and to settle all questions...between the United States and the Dominion of Canada involving the rights, obligations, or interests of either in relation to the other or to the inhabitants of the other, along their common frontier, and to make provision for the adjustment and settlement of all such questions as may hereafter arise". A keystone in the management of Great Lakes water quality is the Great Lakes Water Quality Agreement, first signed in 1972 and renewed in 1978. The Agreement is a formal expression of commitment by each country to restore and maintain the chemical, physical and biological integrity of the Great Lakes Basin Ecosystem. In addition to a number of environmental management and research objectives, the Agreement sets out specific binational water quality objectives and guidelines. Although this framework is potentially a powerful one, the political, economic, social, and regulatory climate in each country is continually evolving. As a result, the provisions of the Agreement do not necessarily keep pace with developments on each side of the international border, and routine audit and enforcement functions are significantly more difficult than would be the case in either country alone.

Scientists and engineers have successfully employed simulation modeling for several decades. Now there is an increasing demand and potential for simulation-modeling based policy decision processes at the local, and regional levels. Policy involves balancing between competing objectives, which often requires multidisciplinary coordination and cooperation. Projecting future consequences of alternative scenarios often requires the explicit consideration of feedback loops among economic, agronomic, hydrologic, social, and ecologic components of the managed system. To address this requirement, a variety of simulation modeling integrating environments are being developed. A classification of fundamental approaches is presented to provide a backdrop for evaluating systems.

This paper presents a strategy for the abatement of pollution from storm-generated sanitary-sewer overflows (SSO). Because of the great lengths of sanitary-sewer systems and their associated vast number of house-service laterals or building connections, it is often less expensive and more feasible to use alternatives to sewerline rehabilitation for infiltration/inflow (I/I) and SSO control. Extensive sanitary-sewer-system rehabilitation can: (1) be relatively costly; (2) take a long time to complete; and 3) be extremely disruptive to traffic, businesses, and property owners. I/I control studies have found that just correcting I/I in street sewers will not necessarily correct the problem because building connections contribute as much as 60% of the infiltration load. Building connection rehabilitation can be infeasible economically because of the shear number of connections or impractical because of the difficulty in dealing with property owners. Inflow elimination or reduction, cost-effective sewer rehabilitation, and collection system inspection with associated clean out and repair must be performed in all cases. In addition, an integrated economic and feasibility analysis using a combination of maximizing flow to the wastewater treatment plant and maximizing treatment capacity must be considered for controlling the remaining SSO. SSO can be abated using combined-sewer overflow (CSO) control methods. SSO and CSO are both mixtures of municipal sewage, stormwater, and ground water.

The aim of the controlled testing program is to evaluate the performance of different coating, lining and grouting materials used in the rehabilitation of wastewater facilities and to quantify the infiltration at pipe joints using a combination of full scale and laboratory tests. For the coating/lining project special testing chambers have been designed and built to verify the applicability of various coating materials to 900 mm (36 inches) concrete pipe under a hydrostatic pressure of 105 kPa (15 psi) is being investigated. To quantify the bonding strength between the coatings and substrates (concrete and clay bricks) several ASTM/CIGMAT test methods are being used. A control test with Holidays has been developed to quantify the chemical resistance of coated materials to acidic environment. Single and multilayer coatings have been under investigation for several years. Epoxy, polyester, polyurea, polyurethane, polymer concrete and plastic liners are being investigated. Based on the test results it was possible to develop relationships and quantify the effectiveness of various coating/lining materials. A combination of grout, grouted sand and model tests are being used to evaluate grouts for leak control at pipe/manhole joints, service connections and cracks. Grouts are being characterize using the working, physical, mechanical and durability properties. For the model tests, 203 mm (8 inches) diameter leaking pipe joints are being used in soil boxes. Grouted joints are being tested to 34 kPa (5 psi) water pressure to quantify the effective reduction in infiltration. Another testing protocol has been developed to quantify the pipe joint infiltration, where 762 mm (30 inches) diameter pipes are being used. A special bladder configuration is being used to pressurize the joints with water up to 48 kPa (7 psi). These controlled verification programs at CIGMAT will be of assistance to manufactures, suppliers, engineers and owners.

The Border International Water Quality Standards Committee of the Environmental and Water Resources Institute of ASCE is developing documents for comprehensive water quality planning and management of shared water resources. The resources may include waters such as the international boundaries between the United States and Mexico or other soverigns such as tribes. In addition to the soon to be published Comprehensive Transboundary International Water Quality Management Agreement, two additional documents are scheduled for development in the next few years including Guidelines for the Development of Border International Water Quality Standards and Criteria and Developing Guidelines for the Development of an International Water Quality Management Plan (WQM Plan). This paper presents the goals and objectives for the latter document and a preview of the proposed content in summary form. The document is being developed by a BIWQ subcommittee (Management Plan Subcommittee). The three documents together are designed to form an integrated approach. Readers with examples of other transboundary water quality management plans are invited to send samples to the authors at the addresses below.

This paper presents the results of some preliminary experiments which have been conducted using a Couette flow rotating cylinder device to quantify the effects of fluid motion on biochemical oxygen demand (BOD). The experiments will provide a correlation between stagnant and dynamic BOD values. The experiments were conducted with E. coli to determine the relationship between energy dissipation rates in the fluid and the associated change in BOD. This will be useful in better characterizing BOD in aquatic and engineered environments.

Temperature and up flow velocity are regarded as the two main parameters significantly affecting microbial ecology and characteristics of UASB systems. The 2.3 m high and 0.25 m²-cross-section UASB pilot used in this study received slaughtery effluent with SCOD in the range of 2000–5000 mg/L. Temperature was varied in the 28–35 °C mesophilic range using an in-line heat exchanger and three up flow velocities studied were 0.3, 0.57, and 1 m/h without any recycling. At least one-week adjustment time was allowed after any change in the conditions. Since granules had been formed previously, the start-up phase lasted for only two weeks and up flow velocity and temperature was maintained at 0.3 m/h and 28 °C, respectively. In the operational phase of the study, organic loading was varied in the 9–49 kg COD/m³.d at 32 and 35 °C temperatures and velocities of 0.5 and 1 m/h.

This document considers important aspects related to the theory, design, and use of elongated stabilization ponds with partitions as a technology to facilitate the sanitary disposal of sewage from small communities. The main objective of this paper is to present a technology for wastewater stabilization ponds design that produces effluents with a very low bacterial (Fecal coliform or Escherichia coli) concentrations without the use of disinfection. This effluent can be used for irrigation in accordance with WHO Health Guidelines for the Use of Wastewater in Agriculture and Acuaculture.

In reviewing any environmental document for technical content, the reviewer typically draws heavily on his/her training and expertise in the area of review. Generally, the idea is to reach consensus on project issues while involving all stakeholders, regulators, industry parties and other concerned parties. Ideally, common goals exist; achieve environmental compliance, remediate a contaminated site, and/or protect human health and the environment from deleterious impacts. To achieve these goals, consensus building, collaboration and cooperation are required; unfortunately, these requirements can be difficult to achieve. Reasons include the inability to agree, miscommunication or total lack of communication, and the situation where decisions affecting the progress or direction of a project become contingent on politics rather than technical issues. When these situations occur, they can result in the loss of trust, problems with negotiations and lack of forward movement towards the goal. In this paper, the experiences and perspective of a reviewer of numerous types of environmental documents are considered. Document reviews considered include remedial investigations, feasibility studies, EIRs, and Site Observational Work Plans for a variety of clients (e.g., Navajo Nation, environmental groups, regulatory agencies, and lawyers).

This paper discusses the errors in existing leachate pipe spacing formulas. In particular, it presents the derivation of the McBean equation and points out that this derivation is in error, since it assumes that the direction of leachate flow is horizontal. The paper asserts that existing leachate pipe spacing formulas which use the liner slope for calculating the spacing are in error. It then proceeds to derive an alternate formula and compare data produced from the two leachate pipe spacing formulas of Moore and Richardson and Koerner (that uses the liner slope in calculations) with the author's formula to point out discrepancies.

Many municipalities throughout the United States have sewerage systems (separate and combined) that may experience exfiltration of untreated wastewater. This study was conducted to focus on the magnitude of the exfiltration problem from sewer pipes on a national basis. The method for estimating exfiltration amounts utilized groundwater table information to identify areas of the country where the hydraulic gradients of the wastewater are typically positive, i.e., the wastewater flow surface (within pipelines) is above the groundwater table. An examination of groundwater table elevations on a national basis reveals that the contiguous United States comprises groundwater regions (established by the U.S. Geological Survey) which are markedly different. Much of the northeastern, southeastern, and midwestern United States has relatively high groundwater tables that are higher than the wastewater flow surface, resulting in inflow or infiltration. Conversely, a combination of relatively low groundwater table and shallow sewer creates the potential for widespread exfiltration in communities located in the western United States.

Increasing concerns about the quality of inland and coastal water-ways coupled with the emphasis on wastewater recovery and reuse has resulted in stringent Environmental Protection Authority (EPA) compliance limits for all wastewater treatment plants. Wetland systems incorporated into treatment trains of wastewater treatment plants not only provide an effective means of nutrient removal but also provide a cheap economical alternative for purifying wastewaters. However, the hydrodynamic behaviour of wetland systems must be understood and utilised to its full potential to achieve optimum wetland treatment efficiency. A tracer study was conducted to assess the hydrodynamic behaviour of a surface-flow (SF) wetland used to polish tertiary treated effluent from the Upper Yarra Sewage Treatment Plant (UYSTP), north-east of Melbourne, Australia. Parameter evaluation allowed a model to be performed through a first order areal uptake rate for total phosphorus (TP) and total nitrogen (TN). This paper highlights the relationship between the wetland hydraulic characteristics and the overall treatment efficiency of the wetland.

Ohio EPA has utilized chemical and biological aspects of streams to develop individual aquatic life use designations for state waters. It is well recognized that sediment reduces a stream's aquatic life use; however, it is difficult to quantify such impacts utilizing chemical data. Recently, Ohio EPA began utilizing innovative techniques to quantify sediment impacts to state waters from construction sites not complying with provisions in the general NPDES permit for storm water discharges associated with construction activity. A field study to determine qualitative and quantitative impact to a stream from a non-compliant construction site was completed utilizing fish electroshocking, Qualitative Habitat Evaluation Index (QHEI), and zigzag pebble count studies. The 33 acre construction site that began in 1996 consists of severely eroded silt and clay loam subsoil located within the 48 square mile drainage of Turkey Creek, Scioto County, Ohio. Lack of implementing best management practices allowed significant amounts of sediment to enter Turkey Creek.

The Internet revolution has swept the world like no other communication technology before it. Not only has it provided a completely new method of delivering information and services with unprecedented speed, but it also has significantly reduced the importance of distance as a factor in the ability of various parties to collaborate and to exchange and share information with one other. Locus Technologies has attempted to capitalize on this explosion of interest in the Internet and on the advances in tools and technologies in this arena by building a suite of Internet-based applications. This suite, named LocusFocus, includes modules for: (1) operating and controlling groundwater treatment and recovery facilities from a web-based browser; (2) managing environmental data; (3) uploading field data into, and retrieving such data from a centralized database using hand-held, wireless devices; (4) storing and retrieving project documents; and (5) collaborating on-line. LocusFocus is the first comprehensive multi-channel dynamic web portal for the environmental industry.

Computational Fluid Dynamics (CFD) modeling offers the potential of improving disinfection contactor hydraulics, allowing a decrease in the applied disinfectant dose without a decrease in the level of microbial inactivation. For treatment systems utilizing chlorine as a disinfectant, this would result in both a reduction in chemical costs and in disinfection by-products (DBPs). Current modeling of clearwell hydraulics is based on accurate prediction of the effluent residence time distribution (RTD) curve. Researchers have shown that CFD models can predict a majority of the experimental RTD curve, but under certain circumstances may not reproduce the entire curve. The objectives of this study were to numerically characterize tracer transport through a disinfection contactor, investigate the impact of grid density, time step interval, and investigate the impact of accurately modeling perforated baffles on the resulting RTD curve.

A multimedia equilibrium model was developed to assess the distribution and environmental concentrations using availableGeographical Information Systems (GIS) databases on the Passaic River Watershed in New Jersey. This assessment was conducted in seven compartments (air, water, sediment, surface soil, terrestrial vegetation, root zone soil and vadose zone soil) and eighteen sub-compartments of the watershed. A spatial resolution is introduced by modeling the watershed as a series of inter-connected sub-watersheds. The watershed representation presents several benefits including a consistent data set since the New Jersey Department of Environmental Protection (NJDEP) regulated facilities and environmental monitoring stations are distributed based on the watershed. The fugacity model developed herein was validated using the peer-reviewed ChemCAN model. Its application to the watershed provided important insights into the fate of contaminants, and better decisions for controlling releases. Furthermore, the inclusion of spatial resolution improved on the results of steady state and equilibrium multimedia model by several orders of magnitude.

The interdisciplinary nature and increasing complexity of water- and environmental-resource problems require the use of modeling approaches that can incorporate knowledge from a broad range of scientific disciplines. The large number of distributed hydrological and ecosystem models currently available are composed of a variety of different conceptualizations of the associated processes they simulate. Assessment of the capabilities of these distributed models requires evaluation of the conceptualizations of the individual processes, and the identification of which conceptualizations are most appropriate for various combinations of criteria, such as problem objectives, data constraints, and spatial and temporal scales of application. With this knowledge, "optimal" models for specific sets of criteria can be created and applied. The U.S. Geological Survey (USGS) Modular Modeling System (MMS) is an integrated system of computer software that has been developed to provide these model development and application capabilities. MMS supports the integration of models and tools at a variety of levels of modular design. These include individual process models, tightly coupled models, loosely coupled models, and fully-integrated decision support systems. A variety of visualization and statistical tools are also provided.

This paper discusses a three-dimensional hydrodynamic and transport "far-field" model developed in conjunction with a "near-field" buoyant plume mixing model to evaluate the siting and design alternatives for the feedwater intake and discharge system of a desalination plant located on a coastal site with a shallow nearshore zone. Interesting aspects include the coupling of the near-field and the far-field models, simulation of discharge recirculation into the intake, and the modeling of drying and flooding in the inter-tidal zone. The study demonstrates the effective use of numerical models as an evaluation and design tool for engineering applications, especially during the feasibility study phase of a project.

The first flush effect brings a multitude of contaminants into surface waters from storm sewers, overflowing domestic sewers, and surface scour. Contained in the first flush are large numbers of pathogen indicators, and potentially pathogens. The pathogen indicators could represent a significant health threat to communities that use storm impacted surface waters for drinking water supplies. However, commonly used bacterial indicators do not provide information about fecal source and age, critical pieces of information required to determine potential pathogen risk and impact. Yet, municipalities face the daunting prospect of prioritizing the installation of best management practices in the absence of easily applied methodologies to sort out the numerous sources of pathogen indicators and quantify the risk each proposes. This paper will present some new analytical and modeling tools that could be of use to municipalities. The first tool is a unique bacterial ratio that varies with age relative to human sewage. The second tool is a neural network modeling approach for classification and ranking of stormwater impacts. Together these tools can point to the predominant stormwater sources in a watershed that bring the freshest, human or agricultural animal impacted, wastes into drinking water supplies.

This paper illustrates how a state-of-the-art systemwide collection system modeling approach employed by the County of Henrico, Virginia enhanced the planning and design of its sanitary sewer overflow control facilities. The paper discusses the following planning components: (1) development of dry-weather wastewater flow projections using a geographical information system equivalent data of existing and projected land uses, existing and projected population density and distribution, existing base wastewater flows from water consumption records, and flow monitoring data from their supervisory control and data acquisition system; (2) prediction of wet-weather rainfall dependent infiltration/inflow using a predictive model with model parameters calibrated and verified with recorded wet-weather flow data; (3) analysis of the capacity of the existing sewer system under present and future conditions using the SWMM EXTRAN model; (4) analysis of the wastewater treatment facility to assess hydraulic and process capacity of unit processes and determine expansion requirements for treating increased flows; and (5) development of a capital improvement program for phased implementation of additional facilities (sewers, storage tanks, pump stations, force mains, and wastewater treatment plant expansion or process retrofitting) to meet the available projected capital investment budget and provide flexibility in the future for constructing improvements when they are needed. This paper also presents the steps that the County has taken to actually implement the capital improvement plan.

The Water Environment Research Foundation (WERF) commissioned the research described in this paper to help municipal agencies and their consulting engineers quantify and simulate rainfall derived infiltration and inflow (RDII) that affects the sewer systems they operate, manage, and design. RDII characterization is used to compare infiltration and inflow (I/I) contributions from various portions of a sewage collection system and to evaluate the effect these contributions have on various system components. RDII contributes to sanitary sewer overflows (SSOs), and to elevated wet-weather peak flows and wastewater volumes at treatment facilities. RDII thus causes undesirable health risks, increases operating costs, and often requires construction of facilities with capacities greater than what would otherwise be required. The research summarized in this paper identified and tested eight major categories of RDII analyses methods in several diverse sewersheds. It identified metrics suitable for objective comparison of the RDII analyses, and concluded with recommendations for selecting RDII methods appropriate to a variety of applications. A team of consultants and cooperating municipal agencies conducted the research. The three cooperating municipal agencies represent a broad spectrum of sewer construction categories and hydrometeorologic regimes. The Montgomery, Alabama Water Works and Sanitary Sewer Board (MWWSSB) represents a community where the sewer system has grown rapidly in the past 20 years. It is a humid, continental climate that is affected by severe thunderstorms and occasional hurricanes. The Metropolitan Council Environmental Services (MCES) group serves more than 100 municipalities in and around St. Paul and Minneapolis, Minnesota, and represents a multi-agency sewershed affected by severe cold weather conditions and summer thunderstorms. The Bureau of Environmental Services (BES) of Portland, Oregon, represents an established community affected by the prolonged, low-intensity storms characteristic of the Pacific Northwest.

The Comprehensive Transboundary Agreement for International Water Quality Management includes a section on the development of a water quality management plan. Prior to implementation of the plan, the signature parties will need to agree on how compliance will be determined; this will require the establishment of mutually agreed upon compliance criteria. Establishment of compliance criteria requires a thorough understanding of the water resources addressed in the management plan. In addition, identification of all agencies that may have regulatory oversight is essential, as is knowledge of the required permits, certifications and/or findings that may impede implementation of a plan. These and other issues are presented. Types of compliance criteria, including non-numerical and numerical formats, are summarized. Numerical criteria pertinant to transboundary agreements, including regulatory guidelines, standards, compliance goals, limits criteria, maximum contaminant levels, and maximum contaminant level goals are discribed.

The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), commonly known as Superfund, was enacted by Congress on December 11, 1980, and provides Federal authority to respond directly to releases or threatened releases of hazardous substances that may endanger public health or the environment. Sites contaminated with PCBs represent a significant number of the hazardous waste sites authorized for cleanup under CERCLA. This paper summarizes the overall decision-making process for developing cleanup plans for Superfund PCB sites. It discusses the Federal requirements that must be met in cleaning up Superfund PCB sites, remedial alternatives for PCB-contaminated National Priorities List (NPL) sites, and EPA guidance used in developing cleanup plans.

Water and natural resources managers have a need for an integrated computational framework that facilitates productive use of the differing computer-based tools, assessment techniques, and databases available to those managers. The Land Management System (LMS) is an effort of the U.S. Army Corps of Engineers, through its Engineer Research and Development Center, to design, develop, support, and apply an integrated computational framework for modeling and decision support technologies relevant to natural and water resources management. This includes management of lands, water bodies, and their interfaces with the atmosphere. This paper presents the functionality required of a computational framework in support of natural and water resources management and decision making. The paper then overviews the LMS and the development path it is taking to meet the requirements of such a computational framework.

A single-layer, steady-state analytic element model was constructed to simulate shallow ground-water flow in the Menomonee Valley, an old industrial center southwest of downtown Milwaukee, Wisconsin. Project objectives were to develop an understanding of the shallow ground-water flow system and identify primary receptors of recharge to the valley. The analytic element model simulates flow in a 18.3m (60 ft) thick layer of estuarine and alluvial sediments and man-made fill that comprises the shallow aquifer across the valley. The thin, laterally extensive nature of the shallow aquifer suggests horizontal-flow predominates, thus the system can appropriately be modeled with the Dupuit-Forchheimer approximation in an analytic element model. The model was calibrated to the measured baseflow increase between two USGS gages on the Menomonee River, 90 head measurements taken in and around the valley during December 1999, and vertical gradients measured at five locations under the river and estuary in the valley. Recent construction of the Milwaukee Metropolitan Sewer District Inline Storage System (ISS) in the Silurian dolomite under the Menomonee Valley has locally lowered heads in the dolomite appreciably, below levels caused by historic pumping. The ISS is a regional hydraulic sink which removes water from the bedrock even during dry weather. The potential effect on flow directions in the shallow aquifer of dry-weather infiltration to the ISS was evaluated by adjusting the resistance of the line-sink strings representing the ISS in the model to allow infiltration from 0 to 100% of the reported 9,500 m³/d. The best fit to calibration targets was found between 60% (5,700 m³/d) and 80% (7,600 m³d) of the reported dry- weather infiltration. At 60% infiltration, 65% of the recharge falling on the valley terminates at the ISS and 35% at the Menomonee River and estuary. At 80% infiltration, 73% of the recharge terminates at the ISS, and 27% at the river and estuary. Model simulations suggest that the ISS has an greater influence on the shallow ground-water flow in the eastern half of valley as compared to the western half. Preliminary three-dimensional simulations using the numerical MODFLOW code show good agreement with the single-layer simulation and supports its use in evaluating the shallow system.

When evaluating the toxicity of arsenic in soil, health assessors should know that a small, but significant, percentage of preschool children might exhibit soil-pica behavior either once or for short periods. If high levels of soil arsenic are present in residential areas where preschool children have access, additional dose estimates are needed to evaluate the acute toxicity of arsenic. In general, health assessors should consider acute arsenic toxicity in children who eat large amounts of soil when residential properties have several hundred parts per million of arsenic in soil. A case study is presented to demonstrate how acute toxicity of arsenic in surface soil could be evaluated.

This project consists of features that will develop a high quality, sustainable drinking water supply for the El Paso-Las Cruces region of far western Texas and southern New Mexico. The project will eventually provide an additional 174.5 million gallons per day of treated surface water year-round to communities and other water users from Hatch, New Mexico to El Paso, Texas. Project features include water treatment plants (WTPs) and associated facilities, aqueducts and diversion structures, aquifer storage and recovery, surface water acquisitions and conversions of raw irrigation water to municipal and industrial use (M&I) by acquiring rights to water through land acquisition forbearance agreements, water conservation and water banking, and finally, fish and wildlife enhancements and mitigations. Project features will be constructed and implemented in three phases to help meet the region's drinking water demands through the year 2030. Five action alternatives and a No Action Alternative were developed and analyzed for the El Paso-Las Cruces Regional Sustainable Water Project. Authors will discuss the criteria for selection of the preferred alternative in terms of environmental impacts, financial feasibility, reliability, sustainability, implementability, and quality of life. Based on detailed analyses, the River with Local Plants alternative was selected as the Preferred Alternative for the project. This alternative includes year-round flows with a river diversion to the Upper Valley Water Treatment Plant in Texas, and additional plants located in New Mexico at Hatch, Las Cruces and Anthony. All of these plants will receive river water throughout the year.

This paper presents an overview of the transport of toxic pollutants through multiple media and drainage systems in the urban watershed during wet-weather periods. It includes the origin of the toxic substances; their transport via atmospheric deposition, overland washoff, and urban sewer systems; and, their impacts on both surface and ground waters. During dry-weather periods, incompletely combusted hydrocarbons from automobiles combine with atmospheric particulates from a host of other sources and deposit on urban streets and other urban surfaces. During a storm event, these solids, in addition to solids from industrial and commercial parking lots, material storage areas, and vehicular service stations are washed off by surface runoff and drained into either separate storm sewer or combined sewer systems. Field studies have identified that a major portion of hazardous waste priority pollutants including benzene, polynuclear aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), pesticides, and heavy metals (e.g., arsenic, cadmium, chromium, copper, lead, mercury, and zinc) contained in urban stormwater runoff are in particulate form or sorbed onto particles. These stormwater particulate pollutants contribute significant toxicity to receiving waters. Mortality, epidermal lesions, or fin erosion can occur in fish and other aquatic life forms that are exposed to these toxic suspended solids and sediments. Methods for intercepting the cross-media transport of toxic constituents in the urban environment include best management practices to control surface runoff pollution; steeper sewer slopeage and improved pipe bottom shapes to maintain high velocity solids-carrying capacity during low-flow periods; and upstream sewer flushing and sediment trapping to reduce clogging and sediment in sewers.

An intricate structure of water laws, policies and institutions in the upper Rio Grande basin provides the framework for operation of nearly a dozen federal reservoirs and related projects by the U.S. Army Corps of Engineers and the Bureau of Reclamation. These two agencies are responsible, respectively, for controlling and safely passing flood flows, and for storing and releasing water for agricultural, municipal / industrial use and other uses. The institutions encountered or affected by the Rio Grande as it flows from its headwaters in Colorado to Fort Quitman, Texas, include two countries, three states, 20 Pueblos and Tribes, two rapidly growing major metropolitan areas, 21 counties, as many local governments and a myriad of acequias and irrigation districts. Associated directly with storing and releasing river water in the upper Rio Grande basin are an international treaty with Mexico, an interstate compact among Colorado, New Mexico and Texas, more than a dozen federal water project authorizations, water laws, and state and tribal water quality standards. Adding to this tangle are about three dozen or so other federal authorities to restore and protect the natural environment, preserve and protect historic and cultural resources, and to protect the rights of Native Americans. Through ongoing collaborative and cooperative efforts, including the Upper Rio Grande Water Operations Model, the Upper Rio Grande Basin Water Operations Review, and others, some flexibilities in operation are being identified, providing a critical step in developing water management solutions.

This paper describes an effort to use Texas and Mexican transboundary water negotiations and cooperation as a device for facilitating Palestinian and Israeli negotiation and cooperation over water quality and quantity in the area of the Mountain Aquifer and the Coastal Aquifer that they share. A training program is being developed to involve Israeli and Palestinian water experts as advisors to simulated discussions between real Texas and Mexican water officials over transboundary water quality issues, including standards and a hypothetical acute discharge accident.

At the dawn of the new millennium, the world is host to six billion people. An accounting of the resource consumption and solid, water and air pollution from this population, the extant controls of the pollution and the related implications of population growth in the 21^st century are the topics of this paper. Two of the world's major industrial sectors, mining and petroleum, are examined in terms of magnitudes of product and wastes generated. Environmental impacts and contemporary environmental controls are described for each category of product development, from exploration to extraction to refinement and restoration. Contemporary problems and practices in municipal solid wastes, urban water management and urban air pollution are presented, following the review of the conservation, restoration, recycle and reuse measures adopted by the industrial sectors. Striking contrasts are revealed between developed and developing countries on the types and management of urban solid waste. Urban area water pollution is shown to be a worldwide problem. The issue of unsafe water supplies and the nature of water pollutants in urban areas are addressed, along with a summary of the prevailing practices for controlling urban runoff and water quality. The ever-increasing threat of urban air pollution is addressed. The characteristics of the problem are explained, and the efforts to combat air pollution in the USA are summarized. As with municipal solid waste and urban water pollution, air pollution is examined in the context of the population explosion in urban areas, which is occurring globally.

Recent technological advancements in hydrologic science and geographic information systems (GIS) have played an instrumental role in analyzing flood control options in the Clear Creek watershed. The development of an effective approach addressing both flood mitigation and ecosystem preservation has been pursued by various agencies for the past 30 years in an effort to preserve one of the last pristine bayous in the Houston / Galveston Bay area. Proposed solutions to the flooding problems by the U.S. Army Corps of Engineers (COE) have focused on large- scale channelization which could jeopardize the creek's sensitive ecosystem and provide limited flood protection as evidenced by the severe flooding experienced in other concrete channelized creeks and bayous in the region. The application of the Hydrologic Engineering Center's latest hydrologic and hydraulic models (HEC-HMS, HEC-RAS and HEC-GeoRas), coupled with GIS and NEXRAD radar, has allowed for the efficient analysis of proposed alternatives to the previous COE plan including voluntary floodplain property buyouts and various, smaller-scale channelization schemes.

The Town of Emerald Isle is a highly developed community located on a barrier island along the coast of North Carolina. The island has high topographic relief due to parallel sand dunes that run the length of the island. Historically, the Town has used multiple permanent and temporary ocean outfalls as its primary means of removing floodwaters. However, recent decisions by the State of North Carolina require the Town to find an alternative solution to severe flooding problems that occur even under normal rain events. The flooding problems have also recently been compounded by the loss of many pine trees on the island (due to hurricanes and a pine beetle infestation) that helped keep the water table lower than current levels during hot, dry periods. To help solve this complex problem, the MIKESHE model is being used. The MIKESHE model offers a full hydrologic solution, dynamically coupling surface and groundwater behaviors. The surface water model includes overland and channel flow components, and the groundwater model includes both saturated and unsaturated zone components. The model also accounts for evapotranspiration losses as well as snowmelt. The project assessed many flood management options including land acquisition, pumping to treatment wetlands, aquifer storage, in-ground storage, and flood proofing. The problems encountered during the assessment include the lack of available land, maintenance or enhancement of a local potable water supply, high-density development, minimal right-of-ways, and restricted wetlands. The computer model was used to assess flood levels for various storms, and develop potential solutions from the preferred alternative of pumping stormwater to treatment wetlands.

In recent years, regional frequency analyses based on annual maximum series (AMS) methods have found wide application, while partial duration series (PDS) methods have not. Typically, the generalized extreme value (GEV) distribution has fit annual maxima, corresponding to generalized Pareto (GPA) distributed threshold exceedances. Previous work has shown PDS/GPA index-flood procedures to be more efficient than index-flood models based on AMS/GEV. This paper discusses the application of a PDS/GPA regional index-flood procedure for updating rainfall intensity-duration-frequency (IDF) estimates for the State of Michigan. The PDS model applied herein assumes independent peaks and a Poisson-distributed number of threshold exceedances. Threshold determination, delineation of homogeneous regions, goodness-of-fit testing, and estimation of distribution parameters using L-moments are discussed. Finally, results from the PDS/GPA procedure are compared to those from a AMS/GEV index-flood method.

Chester County, Pennsylvania is one of the fastest growing areas in the Country, and is experiencing significant environmental impacts due to "suburban sprawl". Northern Chester County is a relatively undeveloped area, but is rapidly experiencing the pressure of encroaching development. This scenic and historically significant area is dependent on ground water for water supply and is traversed by four high quality or exceptional value streams of great environmental and recreational importance to the region. In Pennsylvania, regulations regarding stormwater management and water resources are enacted at the local or municipal level. Municipal boundaries rarely coincide with watershed boundaries, making effective watershed plans difficult to implement. To overcome this difficulty, the municipalities are working together with Green Valleys Association to develop a "Sustainable Watershed Management Program".

Groundwater remediation is associated with enormous costs. According to a recent study by the United States Environmental Protection Agency, the remaining remediation costs for contaminated soil and groundwater in the United States are estimated at 187 billion in 1996 US dollars. A great portion of the costs is tied to pump-and-treat remedies. In recent years, many researchers have shown that optimization techniques can be used in conjunction with aquifer simulation models to design pump-and-treat systems in a more cost-effective manner. However, although significant progress has been made in the theoretical development of the simulation-optimization (S/O) approach, its application to large, field-scale problems remains limited. To demonstrate the applicability and usefulness of the S/O approach under real field conditions, an optimization demonstration project was recently conducted on the Massachusetts Military Reservation in the eastern United States, The project involved the design of a pump-and-treat system for the containment and cleanup of an existing trichloroethylene (TCE) plume approximately 5 km long and 2 km wide in a shallow, unconfined sandy aquifer. The optimization techniques used in the project are based on evolutionary algorithms coupled with a response function approach for greater computational efficiency. The simulation-optimization analysis was performed parallel to a conventional trial-and-error analysis based on simulation alone. The results of the project demonstrate that not only it is possible to remove more TCE mass under the same amount of pumping assumed in the trial-and-error design, but it can also lead to substantial cost savings by reducing the number of wells needed and adapting dynamic pumping. In spite of the large model size of over a half million nodes and a long planning horizon of 30 years, the optimization modeling was successfully carried out on desktop PCs. This field demonstration project clearly illustrates the many benefits of applying optimization techniques in remediation system design.

The study area is the Big Cypress Basin, covering approximately 2,885 square kilometers in southwest Florida. Due to high rainfall and flat topographic features, combined with high water table conditions, wetlands are the predominant habitat. Some wetlands have been drained for urban or agricultural developments. The combination of high groundwater table, extensive drainage systems, and wetlands result in a highly integrated surface and groundwater system. The SWMM model was used to replicate the system's surface hydrology and groundwater interaction in the surficial aquifer. This paper focuses on the groundwater component of the modeling and the interaction with surface water. The groundwater component was calibrated by comparing measured and simulated water table elevations at nine surficial wells, and by comparing simulated and measured baseflow generated at stream gaging stations.

The present paper promotes a novel structure and reasoning processes of flood forecasting models using an artificial neural-fuzzy inference network (ANFIN). ANFIN has a hybrid learning scheme. The unsupervised learning scheme employs fuzzy min-max clustering to extract the information from the input data. The supervised learning scheme uses linear regression method to determine the weights of ANFIN. Compared with the conventional rainfall-runoff models, ANFIN, which learns from the examples, is a model free estimator. Most of the parameters, weights of the network, will be adjusted automatically during the network training. The one-hour-ahead floods of the Chingshui River during tropical storms are forecasted by the constructed models. Our results show that the simple but reliable model is capable of forecasting floods from rainfall by ANFIN.

Watershed management requires consideration of multitude of factors affecting water quality at the watershed-scale while integrating point and non-point sources of pollution and control. EPA's TMDL development tool, Better Assessment Science Integrating Point and Nonpoint Sources (BASINS) provides a GIS-based framework to assist in this process. The development of management strategies using BASINS to meet water quality goals is necessarily a trial-and-error process. Finding management strategies that consider water quality as well as a multitude of other design issues simultaneously via a trial-and-error process is inefficient. This paper introduces BASINS-STAR (BASINS STrategy, Analysis, and Reporting system), a new set of tools to assist decisions-makers explore and identify alternative management strategies. The main engine of BASINS-STAR is a genetic algorithm-based optimization technique, which is coupled with additional tools such as an uncertainty propagation tool, a solution reporting system, and an incremental strategy development system to form a decision support framework. This paper describes these tools and demonstrates its application through an illustrative case study.

A new non-linear network flow solver (SFEP) that combines features of evolutionary programs and network flow algorithms has been designed as a replacement for standard LP solvers used in basin allocation models. It conducts search only within the feasible region and it handles non-linear constraints and objective functions simultaneously during the search process. A case study using the Brantas river basin in Indonesia is presented, containing analyses of solutions obtained with the SFEP algorithm.

The Cape Fear River Basin is the largest watershed in North Carolina (9140 mi²). Explosive population growth has placed severe strains on the water supply systems in the headwaters of the basin. Mandatory conservation measures are placed on the Greensboro — Triad Region as well as the Towns of Gary, Apex, and Holly Springs almost every summer. Better interbasin transfer (IBT) certification procedures are also desired. With all these current factors, regional and state officials saw the need for a basin-wide hydrologic model of the Cape Fear River Basin to better understand current and future water resource management issues. The Cape Fear River Basin Model provides a way for decision makers to assess various impacts of allocating water resources. The model simulates a portion of the basin from the headwaters down to Lock & Dam No. 1, a 5,255 mi² catchment area, beyond which the river is tidally influenced. The model simulates flow conditions for the watershed from 1930–1998. The MIKEBASIN engine is being used for the model. The MIKEBASIN model works within the ArcView GIS environment which offers a substantial timesavings in model input, output, and quality assurance. The project tasks involved an extensive collection and review of existing hydrologic data, interpolation and extrapolation procedures to fill in data gaps, model schematization, estimations of agricultural water use, and incorporation of specific drought management and forecasting policies.

Fundamental components of a hydrologic model include basin topography and topology, loss parameters such as infiltration, a transform method (i.e., unit hydrograph method), and precipitation data. The availability of these data has been dramatically increased with unprecedented amounts of data offered on the World Wide Web. Private organizations and government agencies such as the United States Geological Survey (USGS), Environmental Protection Agency (EPA), Natural Resources Conservation Service (NRCS), and the National Oceanic and Atmospheric Administration (NOAA) have collected, refined, and formatted various types of spatial data for a variety of uses including hydrologic modeling. The advent of Geographic Information Systems (GIS) has helped shape a storage standard for much of these data. Unfortunately, a "data overload" has added complexity and confusion in locating and obtaining the needed data for typical hydrologic modeling and research. Spatial data of primary importance to hydrologic modeling include Digital Elevation Models (DEM) for topography, imagery such as Digital Raster Graphics (DRG), hydrologic soil type, and land use for infiltration losses. Other supporting data types may include Triangulated Irregular Networks (TIN), hydrography, precipitation, and stream stage. To this end, a data acquisition website has been created to assist engineers, hydrologists, and researchers in locating, obtaining, formatting, importing and using the data they need for hydrologic modeling projects. This is particularly useful when no data or GIS databases are locally available. Although the dynamic nature of these data and the internet make this project a never-ending "work in progress", the current results can be found at http://www.emrl.byu.edu/gsda. The GSDA website offers detailed explanations, tips, and direct links to data sources, all in one place. A case study modeling the Lost Creek watershed in Northeastern Utah provides an overview of the data acquisition process, and can also be found at the GSDA website.

We explore the use of chance-constrained genetic algorithms (CCGAs) for stochastic optimization in air quality management. CCGAs allow uncertainties in optimization model parameters to be considered explicitly in the design of least cost strategies. To incorporate uncertainties into the CCGA, the original fitness function is replaced with a Monte Carlo (MC) simulation using Latin Hypercube Sampling (LHS). Strategies are penalized according to how frequently they fail to meet an air quality target. We demonstrate this approach for an air quality problem involving the control of tropospheric ozone. For this problem, we use the CCGA in a multiobjective context to generate a tradeoff curve between control costs and reliability of meeting an air quality target. This analysis is not tractable using classical stochastic mathematical programming techniques such as chance-constrained programming.

This paper presents hydrodynamic and water quality simulation results along the Lebanese coast at both the global and local levels. The global level is a generalized modeling scenario with large geographical scale to obtain the hydrodynamic boundary conditions for the local level, which focuses on the simulation of single-point sources of pollution. The model will support decision-makers in assessing various coastal management strategies and What if scenarios, and in defining critically polluted spots where long term monitoring is required.

What is data management (DM) and why is it important? As described in the Handbook of Data Management, data management is the process of understanding the data needs of an organization and making the data available to support the operations of the organization. The ultimate goal of data management is to provide the seamless access and fusion of massive amounts of data, information, and knowledge in a heterogeneous and real-time environment, and to support the functions and decision making processes of an organization. The important questions that need to be asked for proper data management are: who is going to be using the data, what types of data need to be stored, and how will this data be accessed? With these questions answered, the data management system (DMS) can then be created, or an existing system can be modified to meet the needs of the organization.

The parameters values used in the prediction method for chaotic time series play a significant role in achieving high prediction accuracy. The conventional approach derives these values using, for example, Correlation Dimension, Lyapunov Exponent or Kolmogorov Entropy methods. In the present study, a search engine based on the Genetic Algorithm (GA), is coupled with an Inverse approach to arrive at the optimal values of these parameters. An artificial chaotic Mackey-Glass time series is considered in this study to test the performance of the coupled model, GA and Inverse approach. The study shows that the coupled model yields a prediction error measure, RMSE, of 0.068 which is much more accurate than that of the conventional approach. In addition, the resulting optimal values of the state space parameters are more stable with respect to different data record lengths used in optimization and a change in forecasting lead-time.

Conceptual models are considered to be the best choice for describing the runoff process in a watershed. However, enormous requirements for topographic, hydrologic and meteorological data and extensive time commitment for calibration of conceptual models (both physically based and lumped) are often prohibitive factors in considering this option. Artificial neural networks (ANN) can be an efficient way of modeling the runoff process in situations where explicit knowledge of the internal hydrologic processes is not required. An (ANN) is a flexible mathematical structure that is capable of identifying complex nonlinear relationships between input and output data sets. Neural networks provide model-free solutions. This paper highlights the use of ANN for predicting the peak flow, timing and shape of runoff hydrograph, based on causal meteorological parameters. Antecedent precipitation index, melt index, winter precipitation, spring precipitation, and timing are the five parameters used to develop runoff hydrograph on the Red River in Manitoba, Canada. A feed forward artificial neural network is trained by using back-percolation algorithm. Peak flow, time of peak, width of hydrograph at 75% and 50% of peak, base flow, and timing of rising and falling limbs of hydrograph are the output parameters obtained from the neural network to develop a runoff hydrograph. The ANN generated results are evaluated using statistical parameters; % error and correlation. The % errors in simulated and observed peak flow and time of peak is 6 and 3.6 % respectively. Correlation between observed and simulated values of peak flow and time of peak is 0.99 and 0.88, respectively, thus showing potential benefits of using ANN for developing runoff hydrograph.

Traditionally, groundwater modelers and surface water modelers have treated each other's domain as simple sources or sinks. Computational tools and resources have been insufficient to do otherwise. This longstanding tradition is inadequate to address contaminant migration problems like those facing the Department of Defense (DoD) at active and retired bases and munitions plants. Although contamination often begins as ‘point' sources on the land surface, contaminants may disperse over the landscape and leach into groundwater systems. Groundwater contaminants may also reappear in receiving streams. Assessing the degree of contamination and the risk of future problems is difficult without accurate modeling tools to help guide field sampling efforts and predict contaminant patterns and levels in the future.

A geographical informational system is presented that was developed for the Bushkill Creek watershed to address the needs of various constituencies. The Bushkill Creek watershed located in eastern Pennsylvania covers an area of approximately 200 square kilometers (72 square miles) and is a tributary of the Delaware River. In the past decade, the watershed has experienced rapid development and is expected to be developed at an equal or even more rapid rate over the next 10 years due to linking of two major highways. The need for a watershed geographical information system (GIS) was independently identified by various parties each with an individual interest in the stream. The academic community at Lafayette College saw the stream as having a valuable research potential on issues related to both quality and quantity of water. The dramatic change in land use within the watershed expected over the next ten years will provide a valuable source of data for areas of research interests including watershed runoff modeling, non-point source pollution and water quality modeling.

Information regarding topographic, meteorologic, geologic, and geomorphic characteristics is increasingly available in spatially-explicit digital formats. This information, along with increased computing capabilities (such as faster computers, GIS, etc.), provides the ability to efficiently characterize these spatial features for specific areas. Of interest is whether the inclusion of new watershed characteristics may improve our ability to predict extreme hydrologic events, with particular emphasis on low streamflow prediction. Lumped models of these hydrologic processes (such as regional regression equations) often produce estimators with unacceptably large errors. Using a continuous digital elevation model (DEM) of the conterminous United States, watershed boundaries were developed for 1573 streamflow gauges of the USGS's Hydro-Climatic Data Network (HCDN). The historic discharge records at these sites are considered to be of the highest quality available in the United States. Using the watershed boundaries, numerous digital grids were employed to create a new database of watershed characteristics. The digital grids utilized include a 40-year monthly time series of PRISM's orographically weighted precipitation and temperature grids, the USGS's MUID (STATSGO) geology grids, and the original DEM from which many topographic estimators can be developed. Having grids in digital format allows the efficient processing of the grids, the ability to easily derive a variety of statistics from the grids, and provides more reproducible results than those obtained by manual processing. Specifically, the study investigates the inclusion of new parameters in lowflow regional regression models, and the changes in these models as they are compared across regions. Preliminary results indicate that regional regression models of low streamflow quantiles, which traditionally have very high model errors, could be improved in some regions by including topographic, climatic, and hydrogeologic statistics, though in many regions the models performed poorly.

Deterministic linear and nonlinear programming models have been used extensively to evaluate the most efficient operation of multiple reservoir systems. Unfortunately, one limitation of these models is their inability to provide long-term operating rules that are applicable to actual monthly reservoir management. To address this need, a pattern-recognition procedure, called the Reservoir Operation Screening (ROS) model, was developed to translate the time series of optimal reservoir system decisions into monthly operating rules. ROS uses an embedded genetic algorithm to find the coefficients for piecewise linear approximations to reservoir storage and release values computed by optimization models. The model was developed for the Hydrologic Engineering Center of the U.S. Army Corps of Engineers as a post-processor for their Prescriptive Reservoir Model (HEC-PRM). The paper presents the successful ROS application to the HEC-PRM optimal reservoir storage time series generated for the Panama Canal and Missouri River Reservoir Systems.

Groundwater remediation management does not end with the installation of the cleanup system and flipping the switch. Water quality samples from groundwater monitoring wells are used to verify that the remediation plan is working as planned, and to ensure that there are no unexpected impacts or risks. An important component of the adaptive long-term monitoring and operation system package aLTMOs is a data-driven Bayesian filter, a data assimilation technique that integrates monitoring data and phenomenological modeling results to provide insightful analyses on plume dynamics in both spatial and temporal dimensions. In this process, a model prediction is calculated using the flow and transport simulation. When new measurements are made, they are used systematically to adjust the model prediction. Irregular spatial and temporal data collection can be incorporated. Concentration estimates and their uncertainties are updated as monitoring data are collected. Based on uncertainty analysis in spatial and temporal dimensions and cleanup goals, an optimal monitoring plan is selected. This paper uses a real superfund site problem to demonstrate the application of the data-driven Bayesian modeling technique in uncertainty analysis and redundant sampling reduction optimization in groundwater long term monitoring design.

An approach for determining the dose to a future resident farmer from buried concrete debris with residual radioactivity is presented. This approach has been applied to a commercial nuclear power plant undergoing decommissioning wherein most of the concrete debris will be placed in the basement of the containment building. Ground water concentrations for various radionuclides are calculated using an equilibrium partitioning approach. The RESRAD code is used to determine the corresponding doses for each radionuclide of interest based on the calculated ground water concentrations. Water independent dose contributions from direct exposure to concrete and inhalation of concrete dust are considered as well. Modeling results are used to develop the levels of residual radioactivity in concrete debris that, if disposed onsite and below grade, would result in a dose of 25 mrem/year to a resident farmer.

The derived concentration guideline levels for soil at a commercial nuclear facility undergoing decontamination and decommissioning are developed based on a resident farmer occupying the site in an unrestricted use mode. The allowable total effective dose equivalent for this scenario is 25 mrem/year. Site-specific characteristics, including subsurface geologic stratigraphy, ground water flow direction and gradient, physical properties of the subsurface material, and behavior and metabolic parameters, are used to develop derived concentration guideline levels using the RESRAD computer code. A sensitivity analysis is performed on selected input parameters. The dose contributions from radioactive constituents currently in ground water are calculated separately also using the RESRAD code. Derived concentration guideline levels for soil are then adjusted such that dose contribution from radionuclides presently in the soil plus that from the ground water does not exceed the regulatory limit.

A new parameter estimation method using respirogram and genetic algorithm (GA) to determine the activated sludge model is presented. Simplified respiration model based on ASM3 is used to verify the method. The model is composed of 5 wastewater components and 5 biological processes, which include 9 kinetic parameters. Synthetic data generated by respiration model is used to confirm estimation capability of proposed algorithm. GA adopts root mean square error (RMSE) between original parameter values and estimated values as the objective function. The results of applying this approach show that important kinetic parameters of activated sludge model can be estimated simultaneously using the proposed method. To confirm the applicability of the method, the measured respirogram using the influent of a domestic wastewater treatment plant is used to estimate the wastewater composition.

To manage water quality in watersheds, alternative configurations of detention ponds and land management plans can be generated using a genetic algorithm (GA)-based method to meet target pollutant removal levels at a relatively low cost. Analysis of these alternatives under uncertainty in pollutant loading factors shows that they perform differently with respect to reliability (the likelihood of meeting the pollutant removal targets) and tend to have relatively low reliability (approximately 50%). By extending the GA-based method to incorporate reliability estimation into the evaluation of solutions in the search process, cost-effective pond configurations and land management plans can be generated such that a specified reliability level is achieved. The objective of the search procedure is to identify cost-effective detention basin designs that meet the pollutant removal targets at a specified level of likelihood and also allocate the land use zoning in the watershed to meet system-wide development goals. This approach is extended to generate tradeoff information among cost and reliability. An illustrative application of the procedure to a realistic case study involving a watershed in High Point, North Carolina is presented.

The process of scientific discovery has long been viewed as the pinnacle of creative thought. Thus, to many people, including some scientists themselves is seems unlikely candidate for automation by computer. However, over the past two decades researchers in AI have repeatedly questioned this attitude. The paper describes a specific evolutionary algorithm technique — genetic programming — within a scientific discovery framework, as well as its application on real world data.

Evolutionary computing, of which genetic algorithms are the best-known example, has a relatively short but spectacular history. These simplified models of Darwinian evolution "evolve" optimal or near-optimal solutions to complex problems that would otherwise have escaped experienced engineers or analysts. The Centre for Water Systems at the University of Exeter fosters research in development and implementation of evolution-based tools suitable for applications in clean and wastewater areas of engineering. This paper describes several such tools whose maturity has prompted further commercial development via industrial collaborators. Several case studies are presented demonstrating substantial cost savings achieved using these tools. Further research work that has the potential to be commercially developed and implemented is also introduced.

A groundwater resource evaluation study was carried out in fractured granitic rock for the State Route (SR) 260 highway upgrading project between Payson and Heber in Gila County, Arizona. The RV site was selected for detailed investigation based on preliminary hydrogeologic evaluation. Five exploration wells and seven monitoring wells were drilled at the RV site and aquifer tests were performed to estimate the long-term yields of the wells. The hydrogeologic conditions at the RV well field were complex and strong anisotropic conditions prevailed within the RV well field area. Intensive downhole geophysical logging was performed to characterize the aquifer conditions and the fracture network. In particular, guard electrode electrical logs were used to estimate values of porosity and permeability and acoustic televiewer logs were used to measure the thickness and orientation of relevant fractures. Four longer aquifer tests (ranging from 24 hours to 38 days) were performed to evaluate the long-term, sustainable yield of the well field and the potential impacts that could result from the withdrawal of a large volume of water from the well field. The discrete fracture flow model predicted that the water levels in the well field would decline by 40 to over 100 feet during the life of the project. Water level declines of this magnitude would have the potential of impacting private wells in the communities, nearby springs and a creek.

Researchers at the University of Missouri-Columbia have teamed up with the City of Columbia, Missouri and surrounding Boone County to explore the application of remote sensing information to floodplain management decisions. Bear Creek watershed, straddling the city limits, was selected as a test case for developing updated flood elevation determinations. Assessments of current land cover classifications within the watershed were developed based on satellite remote sensing imagery. The curve numbers determined from land cover classifications and digitized soil maps were used as updated input to an existing HEC-1 modeling framework for the watershed. Peak discharges were calculated at three analysis points that coincide with analyses performed by the Federal Emergency Management Agency (FEMA) and a private consulting firm. As expected, the resulting peak discharges were greater than the FEMA peak discharges (showing the impact of approximately 15 years of additional development). The peak discharges varied 1.2% to 14.4% from the values calculated using the consultant's curve numbers. Peak discharges were converted to flood elevations using FEMA discharge versus water surface elevation relationships. Flood elevations were plotted on the USGS digitized 7.5 minute topographic map to indicate updated flood locations for the three analysis points within the Bear Creek watershed.

For design projects in water resources area, a hydrograph of direct runoff curve is commonly used for the determination of the expected flood volume generated by a given drainage basin in response to a uniform rainstorm. The division of total flow into the direct runoff and the baseflow is of paramount importance for these type of studies. A large sample of natural hydrographs of total flow, chosen from different geographical areas of the 48 contiguous States, is considered for the study analysis in this investigation. These hydrograph curves are analyzed to divide the total flow judiciously into the direct runoff and the baseflow volumetric quantities, respectively. A two-parameter Frechet Distribution is fitted to each one of the hydrographs of the direct runoff curves as obtained through the proposed analysis from these sample hydrographs of total flow. The two individual parameters of the Frechet Distribution are related to the dimensionless shape factor and the storage time constant of the homogeneous drainage basin, respectively. Both parameters are determined through the analysis of the total flow data as measured at a stream gaging station. The calibrated form of the two-parameter Frechet Distribution, representing the direct runoff as the natural hydrograph curve, describes it rather well. It not only furnishes accurate estimates of the flood volume from the computed direct runoff but also provides a compatible length value of the hydrograph timebase. And, of course, helps in the determination of the accurate profile of the corresponding baseflow curve for a given drainage basin under consideration, as well as, furnishes a correct value of the volume of baseflow.

This paper presents the computational framework of a full multiscale method for solving groundwater management modeling. The management model used in this paper, which was developed in previous work, uses an optimal control algorithm called successive approximation linear quadratic regulator (SALQR) to identify optimal well locations and pumping rates for in-situ bioremediation design. The multiscale method integrates a one-way spatial multiscale approach, a V-cycle multiscale derivative calculation and a local effect derivative calculation. Application of this method starts from a coarsest mesh and solves for the optimal solution at that level, then uses the obtained solution as the initial guess for the finer mesh. While at the finer mesh, the method switches back to the coarser mesh to solve for the derivatives and uses those derivatives to interpolate back to the finer mesh. Only the peak area of the derivatives is solved at the finer mesh, with the flat area of the derivatives obtained by the interpolation. Full results combining these methods will be given at the conference, but initial results presented in this paper indicate great potential for computational savings. The reduction of computing time is about 76% for a case with over 1600 state variables. Much more savings can be expected for larger size problems.

The mountainous southwest Virginia is prone to flash flooding. This research concentrates on improving forecast lead time for rainfall by combining WSR88-D Doppler radar, radiosonde and GPS(Global Positioning System) integrated water vapor data. Recently it has been proven that high frequency GPS receivers can be reliably used to measure the amount of water vapor in an atmospheric column by measuring the signal delay. The radar estimates rainfall at lower beam angles from about 100 km radius. The radiosonde data are available only twice a day. The GPS station provides water vapor updates every 30 minutes. It is in this context that the present study will relate the frequently available precipitation precursor water vapor estimates from the GPS receivers to the radar and the radiosonde estimates. The research is carried out with the joint effort between Virginia Tech and the Blacksburg weather forecast office of the National Weather Service.

Holistic modeling embeds water resources and economic sub-models into a single consistent framework and can present a simple approach for building truly integrated water resources and economic models. In addition to the integration of hydrologic-economic approaches, holistic modeling can help address combined environmental-economic issues. At the same time, holistic modeling faces a series of challenges related to data availability, model formulation, and solution approaches. The model formulation typically needs to integrate different temporal and spatial scales inherent to the disciplines integrated into the modeling framework. Moreover, the size and complexity of a holistic model often exceeds the capabilities of existing solution algorithms. This paper will discuss these challenges. A prototype integrated hydrologic-agronomic-economic model for a basin water allocation study is presented as an example of how various spatial and temporal scales can be integrated, and to demonstrate possible solution approaches to large and complex holistic modeling.

Aquifer Storage and Recovery is a concept that will play a role in the solution to the water supply concerns throughout the world, as well as in South Florida, not only for urban users, but also for agricultural and environmental users. Aquifer Storage and Recovery may be a viable method (subject to proper geologic conditions) of increasing water treatment plant efficiency and promoting energy conservation because Aquifer Storage and Recovery projects permit conservation of water during critical times, while utilizing excess resources in plentiful periods. It is generally understood that each Aquifer Storage and Recovery well should be designed, constructed, and tested with the unique goals of the project in mind (e.g. injection rate, storage volume, storage period, recovery rate, water quality of recharge, water quality of native, and water quality of intended recovered use). The proper peer review, and multi-jurisdictional input, in an effort to maximize the information gained, will serve to help clarify the magnitude of Aquifer Storage and Recovery's future in a regional water supply picture.

A genetic algorithm-based search procedure in conjunction with an array of other tools is packaged into BASINS-STAR to form a decision support framework for watershed management. Some of the capabilities of this framework are demonstrated through several illustrative scenarios for the Suwanee Creek watershed in Georgia. Through these case study scenarios, a range of watershed management issues is explored. For example, this paper illustrates a means by which a decision-maker can determine maximum allowable level of land development in a given watershed while maintaining a target level of water quality. In addition, the effect of storm water best management practices (BMPs) on land use planning is also explored.

The impact of physical and chemical aquifer heterogeneities on optimal remediation design and costs is investigated by linking a genetic algorithm optimization library with a contaminant transport simulation model. Various levels of physical and chemical (sorption) aquifer heterogeneities are examined. In the first level, heterogeneity is limited to the hydraulic conductivity (K) field. Then systems with heterogeneity in both K and the distribution coefficient (K_d) are considered. The final level of heterogeneity combines variability in K, K_d, and the mass transfer rate (α). Consideration of K_d- and α-heterogeneities results in different policies and costs compared to cases where sorption heterogeneity is neglected. In general, the total pumping rate increases for systems with both chemical and physical heterogeneity as compared to systems with only physical heterogeneity Although, an increase in K-heterogeneity decreases the impact of K_d- and α-heterogeneities on pumping rates and remediation costs, sorption heterogeneity can be as significant as the physical heterogeneity for the determination of effective remediation strategies.

Conventional methods for estimating the average return period, E(T), and failure risk R, generally ignore serial correlation (persistence) in streamflow. This paper shows that for observed ranges of persistence, E(T) can be up to 65% greater and R up to 27% lower than conventional estimates meaning that the expected design life of a system is longer when persistence is taken into account. Also, by ignoring persistence, low flow quantiles may be underestimated by a half order of magnitude or more. An evaluation of the effect of persistence on drought risk estimation across the U.S. is presented.

Determining the relationship between rainfall and runoff for a watershed is one of the most important problems faced by hydrologists and engineers. This relationship is known to be highly complex with strong correlation between the model parameters. In any model development process, the selection of appropriate model inputs is extremely important. Many authors in the past have attempted to address the issue of selecting the most relevant parameters of a given data set based on sensitivity analysis, yet the effect of interaction of variables is not clearly expatiated. In this study, we use the Group Method of Data Handling (GMDH) technique for selecting the significant variables to be used as input to Genetic Programming, which leads to improved runoff forecasting. The main advantage of GMDH technique is that it considers the interaction amongst the variables while selecting the ones that are significant.

Many watershed models are linked to GIS databases for ease of data retrieval. The level of geomorphologic resolution has a strong influence on model results. Too much detail adds to model complexity and involves greater computer effort. On the other hand, too little detail results in inadequate representation and poor results. This paper will examine the role of geomorphologic resolution on the responses at the watershed outlet, and develop quantifiable criteria for selecting the appropriate level of detail required for modeling surface water movement over watersheds.

An example of the process in developing the watershed model is presented. An essential element in the development is the digital elevation model (DEM) from which a delineation of the stream networks and watershed boundaries is obtained. Topological data contained in the DEM is used to determine flow directions, flow paths and accumulations. These computations serve to establish the HEC-1 interface where parameters such as loss rates, base flow, unit hydrograph and routing data are identified. Time of concentration, lag times and travel time along a routing reach are presented as a critical analytical step. Flood plain delineation is achieved in those cases where the stages of the watershed are needed to predict the impact of extremes in precipitation.

A new approach to groundwater resources, which is based on a multi-criteria decision aid methodology, is presented. The method couples a hydrologic and hydrodynamic groundwater flow simulation model with the decision aid one. Mathematical models are developed to solve flow computations in surface and groundwater by the functions of production, transfer and the Darcy equations. Theses models differ by the chosen method of computation and discretization. Water cycle simulation inside a given basin with connected reservoirs (rainfall, evapotranspiration, efficient rainfall, infiltration, percolation...) allows to modelize groundwater table, discharge flow and evaluate the aquifer recharging. Groundwater modeling in aquifers is done with an implicit finite difference approach. These methods have been applied, with existing code, to modelize the Habibia perimeter in the North of Tunisia, using recent hydrological and hydrogeological data (1966–1998). The calibration of the mathematical model is carried out under a permanent regime by changing the equivalent hydraulic conductivity. Simulation of groundwater table of 1998 proves to be reliable. This study has demonstrated that the integrated network analysis system, GIS, basic data, and hydrological modeling, is an appropriate tool to facilitate the data management and visualization, to enhance the efficiency and effectiveness of the simulation models, and to provide options for better resources water management for the semi-arid regions.

River basin management and planning focuses on understanding the conditions of the water resources in order to meet requirements of various consumers located in a watershed. Numerous aspects have to be considered in order to respond to changes in natural phenomena (e.g. drought conditions), increase in demands, and provision of adequate and good quality water at a reasonable cost to the public. Increased focus on watershed conservation and use of water efficiently requires that water resources planners and managers are able to produce comprehensive and reliable estimates and assess impacts and efficiency of possible strategies. Use of sophisticated graphical user interface and visualization techniques, including supporting technologies such as GIS and WWW, greatly enhances the analyses. It enables users and decision makers focus on transparency and accessibility of results to a broad range of the public including governmental institutions, private and public stakeholders and communities involved/interested in environmental and water resources issues. This paper presents a few examples of applications using DHI's computer modeling systems that individually or in combination can provide an integrated framework for the decision making.

The goal of this study is to use 10 years (1989–1999) of groundwater monitoring data from selected monitoring wells for the preliminary (first line of evidence) demonstration of natural attenuation of chlorinated aliphatic hydrocarbons (PCE, TCE) at the southern sector of the Administrative and Management Area (A/M) of the Savannah River Site Aiken, South Carolina.

The current approach for landfilling of municipal solid waste (MSW) involves the design and construction of liners and caps to keep buried wastes dry. Keeping the wastes dry prevents the decomposition of the wastes and the production of leachates. The prevention of leachate production reduces the pollution of groundwaters. While such a system, if properly designed, constructed, and maintained, should keep the wastes dry, this approach is not without significant deficiencies that will ultimately threaten public health and environmental quality. The dry entombment of MSW is a threat to groundwater quality forever. At some point in time, the structural integrity of the liner system will fail. An alternative approach to the conventional landfilling or the dry-cell is the wet-cell or leachate recirculation method. It represents a new paradigm that is a significant change from current regulatory philosophy. While this approach has been researched for over twenty years, it is receiving renewed interest and there are still significant engineering, design, and operational questions to be answered. This paper identifies those research needs to be addressed in moving to a disposal method that includes bio-technical treatment as a means of achieving sustainable growth.

High-speed computers and GIS technology have permitted the modeling of watersheds as distributed systems. We now have the capability to process spatial information at scales that permit modeling of physical processes with some semblance of realism. Yet, with the current state of the art, it appears that there are at least a couple of issues that need to be resolved in order to significantly move forward in rainfall-runoff modeling. The first is a constraint that is unlikely to be resolved soon and the second is a problem which presumably may be solved with the right analytical tools. These two issues are discussed and prospects for the resolution of related problems are examined.

Remote sensing has been used in the field of hydrologic modeling as a source of data to address the spatial variability of hydrologic processes including storm runoff. Although remote sensing does not directly provide a means of runoff estimation, it can provide quantitative land cover information of suitable spatial resolution that is extremely valuable for model inputs. The USDA-NRCS runoff curve number method is employed in this study to assess the spatial and temporal variability of storm runoff in relation to historical land use changes. The study area was the S-65A sub-basin of the Kissimmee River basin in south Florida. Land use data were obtained from Landsat images for the years 1980, 1990 and 2000, which include a period of development and a period of wetland restoration. Unsupervised classification was performed to assess the changes in land cover, with augmentation from Landsat-derived surface temperatures (for 1990 and 2000 images) and derived vegetation indices. Using the runoff curve number techniques, runoff volumes were determined and comparisons were made. Results show that the temporal and spatial variability of runoff volume resulting from changes in land cover can be readily determined from Landsat images.

The Cosumnes River watershed provides significant flows directly into the Sacramento-San Joaquin Delta and provides habitat for a variety of species. In order to provide competent management of this resource, it is necessary to understand the watershed processes that contribute to the flows in the basin. A physically based hydrologic watershed model is currently under construction for the Cosumnes River. With this model, insights can be gained into the roles played by the different physical processes that contribute flow to the channel. The model can also be used to assess the uncertainties in elements that contribute to the physical characteristics of the basin associated with runoff processes. A module being developed for the model examines low flow processes in the river channel using a diffusion-wave routing routine combined with a Green and Ampt infiltration routine. Results of a low flow study using this module are presented.

In many consulting applications, river flood modelling is performed by a one-dimensional full hydrodynamic modelling system. To model the floodplains with such a system, a ‘quasi two-dimensional approach' can be used. In this approach, the floodplains are modelled as a network of fictitious river branches and spills with the rivers. The river branches represent the topographical depressions (the floodplains, most often with drainage canals at the bed), while the spills represent topographical elevations (e.g. roads, railways) in between these depressions. Also the dikes or the river embankments in between the river and the floodplains are represented by spills. By taking the cross sections of the fictitious river-branches equal to those of the floodplains (cross sections perpendicular to the axis of the river), the storage of water in the floodplains (water levels, storage volumes and spatial extent) is described well. Also the discharges and the water velocities can be modelled for the floodplains if appropriate values are chosen for the friction coefficients in the fictitious river-branches.

A parametric relationship was developed between the available soil moisture and the depth of water table in the vadose zone to characterize the status of Soil-Plant-Atmosphere Continuum (SPAC) located in the flat terrains of Louisiana. These areas are generally situated on the low slopes alluvial soils with extended flat topography around the main drainage system of meandering channels. The stream water surface elevation accurately reflects the status of water table fluctuations in the surrounding flat terrain watersheds. Extensive soil water data, surface hydrology and physiographical information were used to develop and adapt this model for midland flat terrains of Louisiana. The objective of this paper is to report this model and its applicability for monitoring the soil storage capacity in other flat terrain of similar climatic region.

This presentation includes a series of slides that define complex dynamic systems and illustrate models using this system.

The Northern Tampa Bay Area in Florida relies primarily on groundwater to meet the needs of its population. However, groundwater overpumping has placed a strain on the hydrologic system and has had many detrimental effects on the local area. The effects caused by present and projected pumping of groundwater were evaluated using existing and improved numerical models. The existing model was developed by the Southwest Florida Water Management District in 1993. This research focused on improving the model's accuracy using additional data collected from 1989–1998. Predictions of ground water conditions through 2010 were made and compared to previous modeling results. The simulation results were also compared with state defined minimum level needs and current withdrawal reduction plans. Results of this study showed the importance of defining accurate recharge for the system. It was determined from this study that an important parameter for further study is defining recharge; this involves developing a precise method for precipitation measurement. The WSR-88D, or NEXRAD (for Next Generation Radar), is the National Weather Service's weather surveillance radar, in place since 1984. NEXRAD can accurately measure and depict the spatial and temporal patterns of rainfall. Using a GIS-integrated spatial model with NEXRAD data, dynamics in groundwater hydrology can be greatly improved.

The Limay River, situated in the Western South of Argentina, is generated by a large watershed of 30,000 square kilometers (sqkm) located between 39° and 41° of South Latitude. The basin contains 14 glacier lakes and produces a mean annual flow of 736 m³/s. There are three storage dams and power plants with a mean annual generation of 12,000 Gwh. The River Authority asks for a reexamination of the Probable Maximum Flood (PMF) in order to check the safety of the dams under critical situations, define hazardous conditions, affected areas and emergency plans. The regime of the river is a combination of snowmelt and precipitation flows for the upper basins and precipitation for lower elevation basins. The application of the HEC-1 model with the aid of data from 50 telemetric stations (22 streamgage and 28 precipitation and temperature) provides good results in addition to a perfect calibration and verification of the model. For watershed modeling, 25 Hydrologic Response Units were considered.

Given the inherent uncertainty in groundwater management problems uncertainty in determining aquifer parameter values, identifying an optimal remediation strategy based on a deterministic description of the system may not yield an optimal and feasible design. This work builds on the robust genetic algorithm (GA) developed by Chan Hilton and Culver. The robust GA is a simulation-optimization approach which combines a GA with a contaminant fate and transport simulation model and a spatially correlated random field generator to identify tradeoffs between design cost and reliability while considering uncertainty of hydraulic conductivity values. This work evaluates the application of the robust GA to two formulations of a groundwater remediation design problem. In this problem, the objectives are to minimize the cost of the remediation design while satisfying water quality constraints and indirectly maximizing the reliability of the designs. This is done by identifying the location and pumping rates of a set of extraction well used for pump-and-treat remediation. The results show that the robust GA can successfully identify cost-effective and reliable designs in a computationally efficient manner. Future work involving the robust GA and planned modifications also are discussed in this paper.

Water resources planning requires accurate and scientific knowledge of all hydrographic basins. It is fundamental to be aware of the different forms in which water presents it self during the hydrological cycle. The relation between precipitation and flow is beyond doubt the most important factor in the examination of a river flow section. However, other parameters are involved in the hydrological cycle of hydrographic basins, which affect considerably this same relation. The model proposed in this work intends to simulate hydrograms by using artificial neural networks (ANNs). Based on rainfalls and consequent data flows recorded in a hydrographic basin, with an arbitrary rainfall hyetograph, the corresponding hydrographic will be generated. One of the neural network characteristics is its own capacity to learn automatically starting from examples. It is also important to find a network architecture that adjusts to the problem such a learning algorithm that manages to minimise the error function calculated upon the correct output values and those which the network finds in the process. This study was carried out in the hydrographic basin of the Corgo River. However, the purpose is to apply the same work to other basins, giving a better understanding and subsequent management of the water resources of Portugal. The appeal of these kinds of informatic tools, more precisely the neural networks for hydrograms simulation has prove to be very trustworthy, being sensitive to the way the neural networks project new hydrograms. It can therefore be predicted that, after its practical application to a wider range of different cases, the promise inherent in this tool will be both confirmed and expanded.

Alluvial rivers naturally undergo continuous morphological changes caused by relationships between entrained sediment, variable streamflows and dynamic boundaries. However, should sediment degradation reach an excess, the threat to underground utilities, bridges, and levees, as well as other hydraulic structures is significant. Similarly, recurrent deposition can be problematic in that it may cause chronic inundation of floodplain property and reduce valuable storage capacity in reservoirs. By reducing capacity, the useful life of the impoundment is shortened and the economic value and other associated benefits to be earned from the resource are diminished. This paper explains an optimal control methodology and computational model for controlling excess sedimentation in multi-reservoir river systems. The sedimentation control problem is formulated as a discrete-time optimal control problem and is solved by interfacing the U.S. Army Corps of Engineer's HEC-6 sediment transport simulation model with a genetic algorithm. The simulation model is used to implicitly solve governing hydraulic and sediment constraints, while the genetic algorithm is used to solve the overall optimization problem. System-wide constraints that are imposed on reservoir release policies and storage levels are accommodated using a penalty function. The model directly evaluates multi-reservoir management policies that limit sediment aggradation and degradation in river channels and reservoirs. The model is applied to a three-reservoir network from the literature, for which a comparison between the genetic algorithm and an alternative optimization technique can be made. Results of the application indicate that the genetic algorithm and the optimal control approach comprise an effective decision-making tool in sedimentation control.

A management model has been developed that predicts human health risk and uses a noisy genetic algorithm to identify promising risk-based corrective action designs. Noisy genetic algorithms are ordinary genetic algorithms that operate in noisy environments. The "noise" can be defined as any factor that hinders the accurate evaluation of the fitness of a given trial design. The noisy genetic algorithm uses a type of noisy fitness function called the sampling fitness function, which utilizes sampling in order to reduce the amount of noise from fitness evaluations in noisy environments. This Monte-Carlo-type sampling provides a more realistic estimate of the fitness as the design is exposed to a wide variety of conditions. Unlike Monte Carlo simulation modeling, however, the noisy genetic algorithm is highly efficient and can identify robust designs with only a few samples per design. For complex water resources and environmental engineering design problems with complex fitness functions, however, it is important that the sampling be as efficient as possible. In this paper, methods for reducing the computational effort through improved sampling techniques are investigated. A number of different sampling approaches will be presented and their performance compared using a case study of a risk-based corrective action design.

Water resources management problems can be computationally intensive and improved methods are needed to allow solution of more complex applications. In this paper, we present a numerical algorithm designed to efficiently solve optimization applications such as groundwater management problems. The algorithm is a combination of a simple genetic algorithm and a local search method and is called a hybrid genetic algorithm (HGA). As a first step in the development of an effective HGA, this paper presents a new self-adaptive HGA (SAHGA) that can be used to competently solve the problem without extensive trial-and-error experimentation. This paper presents the SAHGA approach and compares its performance with the SGA and a non-adaptive HGA (NAHGA) for several test functions. The results show considerable promise for the SAHGA, which required less than 25% of the number of function evaluations required for the SGA at a 99% reliability level. The SAHGA algorithm was also more robust than the NAHGA, performing optimally across a broad range of parameter values. The next step will be to apply the SAHGA to the groundwater remediation design problem.

Periodicities in drought data analyzed by using data from individual stations, vary widely. Consequently, no firm conclusions about periodicities can be arrived at. An alternative approach is to combine data from several stations by using the empirical orthogonal function analysis. Such a procedure would give a spatial and several temporal components. The temporal series are then analyzed by spectral analysis to determine the periodicities in the data. Palmer's Drought Index and precipitation data from Illinois, Indiana and Ohio are analyzed by this technique and the results are presented.

In the past decade genetic algorithms (GAs) have been used in a wide array of applications within the water resources field. Although usage of GAs has become widespread, the theoretical work from the genetic and evolutionary computation (GEC) field has been largely ignored. Most practitioners have instead treated the GA as a black box, specifying the parameters that control how the algorithms navigate the spaces of each application using trial-and-error analysis. Trial-and-error analysis is a time-consuming, difficult process resulting in an arbitrary selection of parameters without any regard to the fundamental properties of the GA. The concept of "competent search and optimization" as discussed in this work addresses this difficulty by using the available theoretical work from the GEC field to set the population size, the selection pressure, account for potential disruptions from crossover and mutation, and prevent drift stall. This paper provides an overview of a three-step method for utilizing GEC theory to ensure competent search and avoid common pitfalls in GA applications.

This study presents a probabilistic risk analysis of the effect of uncertainty and variability of the health risk associated remediation with bioremediation of PCE and its daughter compounds TCE, DCE and vinyl chloride. The methodology presented incorporates both variability in aquifer characteristics and uncertainty in human susceptibility to exposure. The method is applied to a hypothetical aquifer contaminated with PCE that contains a drinking water well outside the remediated area. The groundwater transport model CORDITE incorporates a total of 13 biological and chemical species. The health effects model analyzes three separate age groups: adults, adolescents and children.

Many areas in the United States have established stormwater detention pond ordinances that require the postdeveloped outflow from a site to discharge at a rate equal to or less than the predeveloped peak flow rate. This may sound like restoring the site to its predeveloped runoff state, but is that really the case? This paper discusses the impacts of increased stormwater runoff volume due to development, and reviews how this phenomenon may impact downstream areas. An example progresses throughout the different sections of this article to demonstrate these concepts. For simplicity, only one rainfall event (24-hour, 8.636 cm) is reviewed.

Engineering Risk Analysis has been a very strong methodology in order to measures the uncertainties presents in all Engineering processes. In the field of Water Quality, the presence of this uncertainty comes from the different sources. Data base, approximation theory, numerical methods for the solutions of the differential equations are some of these sources. This work applies the methods of probabilities to evaluate the uncertainties present in the water pollution analysis processes. The results have shown that even that the method of probability is a very strong method, there are some restrictions to use the method.

Considerable resources have been expended in attempting to restore sites with contaminated groundwater. In the past, the cleanup goals were often established without regard to risk, mandating remediation of groundwater to background or non-detection or maximum contaminant limits. These are often difficult or impossible to achieve and have made site restoration prohibitively expensive. In response to these concerns, risk-based corrective action (RBCA) is becoming a method of choice for remediating contaminated groundwater sites. Under RBCA, the risks to human health and the environment due to contamination are evaluated and measures taken only to minimize the risk to acceptable levels. A major difficulty in RBCA is negotiating an appropriate risk-based limit and a reasonable corrective action approach, particularly given all of the sources of uncertainty in predicting risk. To aid in this process, a new framework for negotiation is being developed that combines an optimization model with simulation models in order to develop risk-based remedial designs that are both cost effective and reliable. The model combines contaminant fate and transport simulation models and health risk assessment procedures with genetic algorithms to simultaneously predict risk and propose cost effective strategies for reducing the risk. To use the model, stakeholders first negotiate the objectives of the remediation, which may include minimizing risk, minimizing cost, and minimizing cleanup time. Then any constraints such as hydraulic head limits or social or economic constraints are considered. In this paper, the steps are demonstrated using a case study.

Results of the set-up and preliminary runs with a hydrodynamic numerical model for the Meldorf Bight on the German North Sea coast are presented herein. An extensive sensitivity analysis with respect to the model settings and parameters was undertaken. Water level and Acoustic Doppler Current Profiler (ADCP) measurements were used to check the model ability in simulating the hydrodynamics along the tidal channels. The results indicate that the model is capable of capturing water levels and currents in good agreement with observations. Maximum discrepancies between field measurements and model results of 6% and 20% resulted respectively in terms of water levels and flow discharges. The approach considered for prescribing the open sea boundary conditions has a major influence on the results. No major differences were found between the resulting depth-integrated velocities obtained from 3D and 2DH model simulations.

Precipitation-runoff models are used to assess the effects of water use and management alternatives on streamflow. Often, ground-water withdrawals are a major water-use component that affect streamflow, but the ability of surface-water models to simulate ground-water withdrawals is limited. As part of a Hydrologic Simulation Program-FORTRAN (HSPF) precipitation-runoff model developed to analyze the effect of ground-water and surface-water withdrawals on streamflow in the Ipswich River in northeastern Massachusetts, an analytical technique (STRMDEPL) was developed for calculating the effects of pumped wells on streamflow. STRMDEPL is a FORTRAN program based on two analytical solutions that solve equations for ground-water flow to a well completed in a semi-infinite, homogeneous, and isotropic aquifer in direct hydraulic connection to a fully penetrating stream. One analytical method calculates unimpeded flow at the stream-aquifer boundary and the other method calculates the resistance to flow caused by semipervious streambed and streambank material. The principle of superposition is used with these analytical equations to calculate time-varying streamflow depletions due to daily pumping.

Future storm surge management will be based on risk analyses including the determination of failure mechanisms of coastal defenses and their probabilities of occurrence as well as the calculation of losses due to inundation. This paper presents an example of a risk analysis carried out for the coastal region between the two major ports Wilhelmshaven and Bremerhaven. In order to supply the decision-makers and stakeholders with easily accessible information on storm surge management the results of the risk analysis were introduced into a Geographical Information System (GIS) called RISC — Risk Information System Coast.

This paper presents a methodology and computational model for the time dependent evaluation and optimization of dam operations. The optimal dam operation scheme is defined as that which minimizes environmental and ecological impacts caused by water level fluctuations, subject to the maintenance of a navigable stage within the river channel. This problem has been formulated as a discrete-time optimal control problem in which a hybrid genetic algorithm has been interfaced with an unsteady hydraulic simulation model. FLDWAV, a public domain, one-dimensional finite difference model developed by the National Weather Service, is used to solve governing hydraulic constraints, while the genetic algorithm is used to solve the overall control problem. The modeling results can be developed into an operating rule for individual locks and dams. Capabilities of the model are demonstrated through application to a hypothetical three-reservoir river network. The example demonstrates that the applied methodology comprises a comprehensive decision making mechanism that can be used by reservoir managers to control unnecessary ecological impacts.

Increasingly, engineers are using computer models for wastewater treatment plant design. While the use of models allows designs to be examined and tested quickly, the design problem itself is still very complicated. Genetic algorithm (GA)-based optimization provides a means for automating parts of the design process, allowing comprehensive and simultaneous consideration of design objectives and constraints. We demonstrate the use of a GA for a hypothetical case study and show the solutions generally to be superior to those obtained through random search and a conjugate-gradient local search.

Freshwater lenses overlying saltwater commonly occur in coastal areas. Frequently, the thickest parts of lenses with the highest quality water occur in close proximity to the shore under hills, beach ridges, and dunes rather than beneath areas of lower topographic relief even though these may be farther from the ocean. The seasonal precipitation pattern of the middle and lower latitudes increases these variations in lens quality. The higher topography protects the lens from losses due to evapotranspiration. In addition, the longer flow paths followed by the infiltrating precipitation dampen the "flashiness" of recharge event, thus minimizing water table fluctuations and the resultant disturbance at the transition zone. The two dimensional, density-dependent, fluid flow and mass transport mathematical model SUTRA-GUI is used to model the effects of varying recharge and evapotranspiration rates in aquifers with different permeabilities and dispersivities. The model is an effective tool for predicting lens configurations. The model can also be used to assess the sustainable yield of the lens by treating withdrawal as an increase in evapotranspiration. The implications of these findings regarding the impacts of land use activities that could result in the lowering of the topography are discussed.

The continuing trend of urban growth and development creates the need for updated ground cover information for a wide range of applications. Some applications relate to models used in hydrologic, water quality control, and watershed management while other applications respond to specific needs of urban managers. The results presented here are the outcome of work carried out during the last two years for the cities of Springfield and Columbia, Missouri using high spatial resolution satellite data. The challenge that had to be met was to determine the usefulness and limitations of these data sets to enhance or effectively replace conventional data sources. Panchromatic air photos are the most common source of spatial information by urban managers. In some cases photos acquired by federal agencies are inexpensive information sources, however, in many cases municipalities have to contract new air photo coverage or use the new generation of satellite images to satisfy their needs. Airphotos have been replaced by satellite image data for large area (regional scale) mapping because of the multispectral characteristics, digital format and low cost per area of the latter. New satellite image data with spatial resolutions ranging from 5 to 1 meter provide a new data option for selected applications. The subject discussed in this paper is the application of this type of satellite image data for mapping impervious and bare ground surfaces, and for determining runoff curve numbers (CNs) required by hydrologic and environmental computer models.

The main objective of this paper is modeling of the nitrate load in the river outlet of a dominantly rural catchment using the simulation models DRAINMOD and MIKE 11 in combination with a regional GIS, containing major data layers of the catchment. In addition to describing the DRAINMOD-GIS approach in combination with the MIKE 11 model, for simulating the NO₃-N fluxes in the land phase and the river draining the catchment, the methodology is tested using data of the Molenbeek river catchment situated in the Flemish region of Belgium. The sensitivity analysis indicates that the nutrient load at the catchment outlet is most sensitive to the nitrification rate (K₄) and mildly sensitive to the denitrification rate (K₆) in the nitrification process and insensitive to the dispersion coefficient (D) in the one-dimensional advection-dispersion equation.

Non-point source pollution is well recognized as one of the most critical environmental hazards of modern times. In Illinois, non-point source pollution is the major cause of water quality problems, and soil erosion from agricultural lands is the major source of such pollution. Accelerated by anthropogenic activities, soil erosion reduces crop productivity and leads to subsequent problems from deposition on farmlands and in water bodies. Watershed management, however, promotes protection and restoration of these natural resources while allowing for sustainable economic growth and development. In this study a discrete time optimal control methodology and computational model are developed for determining land use and management alternatives that minimize sediment yield from agriculturally dominated watersheds. The methodology is based on an interface between a genetic algorithm and a U.S. Department of Agriculture watershed model known as Soil and Water Assessment Tool (SWAT). The original structure of the SWAT model is preserved and modifications are embedded for computational efficiency. The analysis is based on a farm field level to capture the perspectives of different stakeholders. The model thus supports illinois EPA's plan of developing a program based on enabling and empowering local stakeholders to take charge of the fate of their watershed. Management alternatives available for all land uses modeled by SWAT are developed considering rotation patterns of three years. The decision support tool is applied to Big Creek sub-watershed in the Cache River watershed, located in Southern Illinois. Big Creek sub-watershed has been sighted by the Illinois EPA for excessive sediment and nutrient loadings and has been targeted by the Illinois Pilot Watershed Program. This research is part of an ongoing effort to develop a comprehensive decision support tool that uses multi-criteria evaluation to address social, economic and hydrologic issues for integrative watershed management.

Vitri is an object-oriented framework implemented in Java for high-performance distributed computing. Using Vitri, applications can engage in cooperative problem solving by dividing their tasks among heterogeneous clusters of workstations and PCs. Vitri's features include basic support for distributed computing and communication, as well as visual tools for evaluating run-time performance, and modules for heuristic optimization. It balances loads dynamically using a client-side task pool, allows the addition or removal of servers dating a run, and provides fault tolerance transparently for servers and networks. Among its more powerful features are modules for heuristic optimization, including an asynchronous global-parallel genetic algorithm that is particularly suited for coarse-grained tasks executing on processors with large variations in processor speeds. By using dataflow techniques, in which computations are explicitly based on the availability and forwarding of data, the usual end-of-generation synchronization points are removed from the algorithm. Results are presented for illustrative applications in water distribution network design and air quality management.

Standard statistical methods to estimate peak flood discharges are not applicable to arid environments, such as the southwestern United States, because most watersheds in this region are ungaged and do not have stream discharge data. Watersheds that do have discharge data usually have short periods of record with many years of no flow. Instead, rainfall-runoff models, such as HEC-1 and HEC-HMS, are used to estimate peak discharges. In these models, the accounting for initial abstraction (Ia) and infiltration loss of precipitation is a critical calculation. The SCS Curve Number (CN) approach is commonly used to account for precipitation losses in rainfall-runoff models. The CN approach was developed from studies of natural rainfall and runoff from small [less than 4 ha (10 ac)] agricultural watersheds in the Midwest and southeast United States. In these areas, the approach has been shown to produce reasonable results. However, the one study of the approach in the semiarid southwest did not produce satisfactory results.

Researchers at Virginia Tech have put together the primary structure of a web enabled integrated modeling system that has potential to be a planning tool to help decision makers and stakeholders in making appropriate watershed management decisions. This paper describes the integrated system, including data sources, collection, analysis methods, system software and design, and issues of integrating the various component models. The integrated system has three modeling components, namely hydrology, economics, and fish health, and is accompanied by descriptive ‘help files'. Since all three components have a related spatial aspect, GIS technology provides the integration platform. When completed, a user will access the integrated system over the web to choose pre-selected land development patterns to create a ‘what if' scenario using an easy-to-follow interface. The hydrologic model simulates effects of the scenario on annual runoff volume, flood peaks of various return periods, and ground water recharge. The economics model evaluates tax revenue and fiscal costs as a result of a new land development scenario. The fish health model evaluates effects of new land uses in zones of influence to the health of fish populations in those areas.

The Illinois River is one of the major tributaries of the Mississippi River in the central United States with a drainage area of 75,156 square kilometers. The Illinois River connects the Great Lakes with the Mississippi River through the Illinois Waterway that consists of eight lock and dams along the Illinois River and its tributaries. Because of its central location in the state and being the receiving river downstream of the Greater Chicago metropolitan area, the Illinois River has experienced significant changes and pollution over the last 100 years. At present, however, the Illinois River has become the focus of state and federal restoration efforts. One of the major restoration concepts is the reconnection of the Illinois River with its floodplain. Since much of the floodplain has been leveed off for agricultural uses, the reconnection issue is controversial and expensive. However, large floodplain areas that previously were agricultural lands have been purchased by governmental and non-governmental agencies for restoration purposes. It is anticipated that there will be more such purchases in the future. This paper evaluates the interaction of the Illinois River with its floodplain using hydraulic models to better understand the influence of restoration efforts on river hydraulics. The models will be used to evaluate changes in water discharges, elevation, and velocities as different parts of the river and floodplain are reconnected. Different alternatives for reconnection are also to be evaluated.

Artificial recharge in the Lower South Platte Basin started in the 1970s in Logan County near Sterling, Colorado. The South Platte Ditch was the first ditch company to develop and utilize the re-regulated flow accretions to the South Platte River resulting from the artificial recharge into an off ditch recharge basin. Since that time, artificial recharge in the South Platte Basin has been used to re-regulate excess river flows and generate river accretions during times of flow shortages. Numerous ditch and reservoir companies, municipalities, water districts and private individuals average over 4.94 x 10⁷ m³ (40,000 acre-feet) of annual diversions to recharge resulting in annual river accretions of 1.73 x 10⁷ m³ (14,000 acre-feet). Historically, artificial recharge accretions have been used to replace depletions caused by alluvial large capacity irrigation wells. The basin recession response to alluvial withdrawals and artificial recharge are an important component in the overall management of the basin's water resource. Water quality of the recharge source and receiving alluvial resource is becoming more of a concern with regard to the potential of groundwater quality impairment. Specifically, nitrate loading of the alluvial resource and the attenuation of nitrates through the alluvial aquifer has been investigated by several state and federal agencies.

Aquifer storage and recovery is recognized in the USA as having a significant role for inter-season storage of drinking water, and in Europe and Australia also for its potential for water treatment. However a better knowledge of water quality changes during aquifer storage and recovery, along with better understanding of sustainable treatment processes in aquifers is necessary to enable water utilities to take advantage of this technique. The usefulness of aquifer storage and recovery to improve the quality of injected water is being investigated at several sites. Specific interest is on the attenuation rates of microbial pathogens and organic compounds (both natural and synthetic) in saturated groundwater at artificial recharge sites. Microbial pathogens of particular interest are enteric viruses and protozoa, while the organic chemicals being investigated include several disinfection-by-products and endocrine disruptors. The aim is to encapsulate the data obtained from this investigation into models for the prediction of changes in water quality, and which can be used by water utilities and regulators to evaluate pretreatment requirements for aquifer storage and recovery. This will also improve accuracy of information for the protection of the health of consumers and the environment.

A variety of methods exist for the rapid assessment of stream reaches. They vary widely in the type of data collected, the complexity of the methods, and the conclusions that can be drawn from the results. Relying on a variety of these methods as a basis, the Patrick Center for Environmental Research of The Academy of Natural Sciences in conjunction with the University of Delaware developed a method to assess streams based on geomorphic, habitat and riparian features. Over 60 km of streams including 426 stream reaches were assessed during a 2 month field effort. Analysis of the data produced an overall Stream Quality Index (SQI) that was used to classify streams into four major categories: severely impaired, impaired, moderately impaired, and slightly or non-impaired. The SQI rating was used in conjunction with other natural resource inventory data to aid in restoration planning and overall management of the Fairmount Park system.

There are several limitations to the current methods of measuring bed load in gravel bed stream. To combat these limitations a new devise, the Gravel Transport Sensor (GTS), has been developed by D & A Instruments. Preliminary testing on a GTS prototype was conducted to examine the instrument's ability to detect different size particles over a range of flow conditions. Preliminary results showed the ability of the GTS to detect particles moving as bed load reduces with a reduction in particle size.

Traditionally, bed load transport processes are examined in a simplistic manner, as if they occur under steady state flow conditions. Considering that the vast majority of bed material is transported during unsteady flows, floods, such an approach needs to be re-examined. One set of bed load data from a perennial and another one from an ephemeral gravel bed streams are analyzed here to gain a better understanding of this phenomenon. The results show that the pavement layer controls the release of the bed material and thus greatly influences the transport rates during the passage of a flood. This effect needs to be taken into consideration in future efforts designed to improve the modeling of bed load transport processes.

The Huntington District of the Corps of Engineers is working to develop better operating strategies for reservoirs in the Big Sandy River Basin in order to respond to the conflicting desires of multiple stakeholders in the basin, including flood control, whitewater recreation, water supply, and water quality. A modeling tool was developed using STELLA software to assist the Corps in quickly and easily evaluating operating scenarios and investigating impacts to the various stakeholders.

Measuring bed load in a sand bed channel is extremely difficult, if not impossible. Equipment such as the Helley Smith sampler is not completely suitable to measure bed loads in a river with a dominant sandbed load. Research was conducted to determine the amount of bed load that moves as sandbars on the Kankakee River in Illinois. These data are extremely valuable in determining the impacts of sand movement as bed load on aquatic habitats of the river that depend on gravel or rocky substrate. Several miles of the Kankakee River flows on a rocky substrate that may be affected by sand moving as bed load from the upstream straightened reach of the river. The upper reach of the Kankakee River was straightened about 100 years ago, resulting in excessive sediment load that has been alleged to affect aquatic habitats within the lower reaches of the river. For a segment of the river extending about 130 kilometers, river cross-sectional data were collected in 1966, 1968, 1977, 1978, 1980, 1994, and 1999. Data from all cross sections were not collected at all those time periods. However, a comparison of the volumetric changes for several time periods showed a distinct pattern of bed load movement from one period to another. For example, about 16 percent of the 1980 volume for one specific reach was lost to sediment deposition by 1999. Similar variability including changes in volumes from upstream reaches toward downstream reaches was evident within the lower 42 kilometers of the river. These data can be used to estimate the amount of bed load that may have moved through this river.

This paper discusses the opportunities and implementation procedures of the Corps of Engineers' Ecosystem Restoration Program as it applies to the Arkansas River ecosystem within the City of Pueblo, Colorado. The study area for this wildlife restoration and recreational opportunities study is along the 10-mile reach of the Arkansas River, from immediately below Pueblo Dam to approximately 10 miles downstream to its confluence with Fountain Creek.

This paper presents the results to-date from a continuing investigation into the differences between total suspended solids (TSS) and suspended-sediment concentration (SSC) data and the ramifications of using each type of data to estimate sediment loads. It compares estimates of annual suspended-sediment loads that were made using regression equations developed from paired TSS and SSC data, to annual loads computed by the U.S. Geological Survey (USGS) using traditional techniques and SSC data. Load estimates were compared for 10 stations where sufficient TSS and SSC paired data were available to develop sediment-transport curves for the same time period that daily suspended-sediment records were available. Results of these analyses indicate that as the time frame over which the estimates were made increases, the overall errors associated with the estimates decreases with respect to loads computed using traditional USGS techniques. Using SSC data to compute loads tends to produce estimates closer to those computed by traditional techniques than those computed from TSS data. Loads computed from TSS data tend to be negatively biased with respect to those computed by traditional USGS techniques.

In this paper a Decision Support System (DSS) for operation of multipurpose reservoirs with hydropower facilities is presented. The DSS system consists of six main modules: Database Management, Short-term and Long-term Inflow Forecasting, Long-term Operation (strategies), Short-term Operation (tactics), and Real-time Operation. The Deterministic and Stochastic Dynamic Programming Models are used to develop optimal operating policies for reservoir operation in a monthly scale. In this study, these models are developed and real cost function was incorporated based on reasonable estimates of water and energy prices. Conflicts between value of hydropower generation in different hours of a day and value of water allocation to different demands are considered in order to determine the optimal operation of reservoirs. The short-term model that is developed by using linear programming method is used to develop hourly and daily operating policies. The short-term energy export objectives are considered in long-term optimal operation planning. In this way, long-term policies are used in line with the short-term objectives.

Design flood determination is most often based upon one of two methodologies. When the information is available the design flood is based upon flood frequency analyses of historic records. In many other instances the design flood is based upon the methodologies presented in the United States Soil Conservation Service (SCS) Handbook of Hydrology. Numerous examples of floods exceeding the anticipated magnitude or design frequency exist throughout the United States. This paper will hopefully encourage engineers to review the suitability of their designs over a range of conditions that might be expected to occur. This paper will summarize selected floods, provide an example where a standard design analysis does not solve a frequent flooding problem, and present four often overlooked reasons for flood magnitudes greater than anticipated. Flood frequency analyses based upon historic records are typically developed using the largest flood of record for each year and do not incorporate additional floods during that year. By default, this has the direct implication of reducing the magnitude of a flood for a given return frequency. The level of impact will be site specific and will relate to the site's climatic variability.

The need for guidance on engineering related subjects has resulted in more emphasis on providing professional standards for investigative methods as well as field procedures. An example of this process is the development of a standard for artificial recharge of ground water as an outgrowth of several related manuals and symposia.

Applications of aquifer storage and recovery (ASR) technology can cause land subsidence due to the net compression of one or more semi-pervious clay beds. ASR technology is employed to withdraw and inject water from or into aquifers for various purposes. In order to estimate the potential risk of aquifer system deformation in response to an injecting-pumping scheme, a set of four analytic solutions for the one-dimensional case of a conceptual sandwich model are found. Each solution corresponds to one of four different boundary conditions. Each boundary condition comprises a linear change of pore-water pressure with time plus one of four periodic functions. The periodic patterns are trapezoidal, rectangular, triangular, or sinusoidal changes of pressure with time. Solutions are analyzed for a unit column of an idealized compressible semi-pervious layer. A complete mathematical description includes an initial condition, two sets of boundary conditions and a governing equation that is expressed directly in terms of the vertical displacement of the skeletal frame. For simplicity, the saturated aquifer system is assumed to behave like poroelastic material (both recoverable and nonrecoverable). The two idealized aquifers (one above the modeled semi-confining bed and the other beneath) can be pumped independently of each other. Results from the analytic solution are applied to estimate and predict the potential risk of land subsidence due to ASR applications and to provide a first-estimate type of guideline for city and regional planning and the exploitation of water resources.

The Sacramento River Flood Control Project is a system of levees and flood control facilities along the Sacramento River, its tributaries, and distributary sloughs that protects low-lying areas of the Sacramento Valley and the Sacramento-San Joaquin Delta from damaging floods. The Sacramento River Bank Protection Project (SRBPP) was authorized by the Flood Control Act of 1960 to provide ongoing protection to flood control project components. During field reconnaissance conducted in 1998, a bank erosion site was identified at River Kilometer 239.8 (River Mile 149.0) on the Sacramento River where the erosion was found to be severe, active, and threatening the integrity of the adjacent project levee. Under the authority of the SRBPP, engineering and environmental analyses were conducted to determine a solution for preventing continued bank erosion while protecting the environmental resources present at the site. Through a process of coordination between the U.S. Army Corps of Engineers, the State of California, and environmental resource agencies (U.S. Fish and Wildlife Service and the National Marine Fisheries Service), design plans and specifications were developed for a project that includes both bank protection features as well as environmental features to enhance riverine habitat and provide for onsite mitigation of environmental values lost during construction.

A flood management system used for urban rivers in Japan is presented in this paper. The system is composed of three subsystems: on-line data collection subsystem which is used for collecting rainfall and water level data; flood prediction subsystem based on the previous 3-hour hydrologic data; and result display subsystem. The on-line data collection subsystem is used to collect necessary rainfall and water level data for flood prediction in short periods of 10 minutes. The flood prediction subsystem is composed of effective rainfall estimation, slope flow model, and channel flow model, which integrates the effect of land use, rainfall intensity, and the drainage facilities in the river basin. The purpose of the display subsystem is to provide necessary hydrologic data for all users, which is developed with the combination of the WWW (World Wide Web) explorer and may be linked with the Internet. This system was developed in 1998 and was used for practical flood prediction later. The functionalities of every subsystem were tested and the more efficient application will be expected.

The High Plains States Groundwater Demonstration Program was initiated in 1983 in response to widespread concerns regarding the potential depletion and degradation of groundwater in the arid Western United States. The program consisted of 14 applied groundwater recharge demonstration projects and investigations to evaluate the effective use of recharge under a variety of hydrogeologic and institutional circumstances. A program summary report was issued in late 2000 to describe the program results and experience concerning groundwater recharge. The authorizing legislation designated the Bureau of Reclamation as the lead agency to administer and coordinate program activities. Applied demonstration projects were undertaken through cooperative arrangements with water management agencies and research organizations. The program also sponsored investigations by the Western States Water Council and the National Academy of Sciences to examine issues that can influence the appropriate role of recharge in water management. The demonstration projects represented a variety of water management problems and mechanisms to accomplish recharge objectives. Eight projects involved recharge to augment municipal supplies, four were intended to supplement irrigation water, and two projects involved generalized recharge of groundwater resources without direct recovery. Recharge technologies included active and gravity injection wells, spreading basins, and watershed practices used to enhance natural recharge.

In order to get a most efficient hydraulic and energetic operation from a reservoirs system in a generating company, it is important that the information and the necessary steps for a decision making are available at all the areas involved in a fast, secure and synchronized way. Regarding that COPEL's Hydrology of Operation Department proposed in 1997 the development of a storage, processing and data consulting system— The HMS System—integrating the several data and software used in reservoirs monitoring. The system development and installation were gradual, started with the Caxias' reservoir. In December of 1999 all the reservoirs operated by COPEL were already being monitored by the HMS System. Among the benefits that the project brought to the company, stand out: a) convergence of information for an homogeneous database; b) automation of procedures: collecting of data, calculations and supporting process for decision making (automated operative rule); c) fast results; d) improvement of the quality of information; e) system integration; f) technological evolution.

The US Army Engineer District, Sacramento, has completed development of system-wide, hydraulic numerical models of the Sacramento and San Joaquin River Basins located in California. The models are being used to study alternatives for flood damage reduction and ecosystem restoration. These models include UNET, HEC-RAS, and FLO-2D. The emphasis of this paper is to provide and share information regarding the UNET and HEC-RAS modeling of the San Joaquin River basin conducted for this unusually large modeling effort. Both of these models include about 362 river km (225 mi) of the mainstem channel and an additional 303 river km (189 mi) of tributary, distributary, and bypass channels. All tallied, the UNET model consists of about 2100 cross sections, 84 storage areas, and multiple connections that link the various elements together. Given the extent of the model, impacts from alternative measures in one part of the system can be determined throughout the entire river system, thus, providing the user with a system-wide or watershed-scale result.

Frictional characteristics of high-gradient streams are not well described by current equation. In the present study, a new functional relationship is proposed which accounts for form resistance of the step bedforms, as well as the grain resistance of the gravel particles. By analyzing laboratory flume data for step-pool bedforms, a resistance relation based on the Darcy friction factor is proposed.

This paper presents a hydrodynamic modeling study for Loch Raven and Pretty Boy Reservoirs in the City of Baltimore, Maryland. The major purpose of this study is to generate hydrodynamic information and temperature distribution to drive the eutrophication models of the two reservoirs. The hydrodynamic models are developed by configuring the CE-QUAL-W2 modeling framework with site-specific topographical data, boundary and initial conditions. The models are then calibrated with measured temperature data in 1992. The simulation results show that the models are proper numerical representations of the prototypes, thus are potentially applicable to drive further water quality calculations.

Generally speaking, the absolute elevation of Qingzang plateau is more than 4000m, and the most area higher more than 5000m is covered by snow and ice for whole years. The flow of rivers connecting with glacier and ice cover is not only relative to rainfall, but also temperature and the situation of snow and ice. All these factors consist of the special hydrologic conditions and characters of Qingzang plateau. The paper based on observation and investigation discusses the hydrologic features of NianChu River in Qingzang plateau. Because the surface water accounts very small (about 20%) in forming flood process, and the annual flow process has a close relation to temperature etc, the surface water process graph shows a smoothly changing process. The most flood disasters are generally not caused by rainstorm, but the flood initiated by the bursting of glacier end Moraine Lake or the flood initiated by collapse of landslide body which blocks the river channel. Accordingly, the bursting prediction of end Moraine Lake and calculation of bursting flood is the key to predict and calculate the flood of this region.

The U.S. Geological Survey (USGS) has completed a preliminary analysis to identify streamgaging stations needed in a base network that would satisfy five primary Federal goals for collecting streamflow information. The five goals are (1) determining streamflow at interstate and international borders and at locations mandated by court decrees, (2) determining the streamflow component of water budgets for the major fiver basins of the Nation, (3) providing real-time streamflow information to the U.S. National Weather Service to support flood-forecasting activities, (4) providing streamflow information at locations of monitoring stations included in USGS national water-quality networks, and (5) providing streamflow information necessary for regionalization of streamflow characteristics and assessing potential long-term trends in streamflow associated with changes in climate. The analysis was done using a Geographic Information System. USGS headquarters staff made initial selections of stations that satisfied at least one of the five goals, and then staff in each of the 48 USGS district offices reviewed the selections, making suggestions for additions or changes based on detailed local knowledge of the streams in the area. The analysis indicated that 4,242 streamgaging stations are needed in the base network to meet the 5 Federal goals for streamflow information. Of these, 2,692 stations (63.5 percent) are currently operated by the USGS, 277 stations (6.5 percent) are currently operated by other agencies, 865 (20.4 percent) are discontinued USGS stations that need to be reactivated, and 408 (9.6 percent) are locations where new stations are needed.

Lack of integration of geomorphologic, hydraulic, and ecological criteria has hampered efforts to implement holistic approaches to stream restoration. We propose a design framework called stream naturalization that integrates geomorphology, hydraulics and ecology to improve the environmental quality of degraded streams. Research to support naturalization has focused on agricultural streams in East Central Illinois. This paper compares physical and biological conditions in meandering and straight reaches of a 3^rd order stream. The meandering reach exhibits greater three-dimensional habitat structure compared to the straight reach. Fish density, biomass, and diversity also are greater in the meandering reach compared to the straight reach. Together these findings suggest that stream geomorphology, through its influence on habitat diversity, has an important influence on fish community structure. Naturalization designs that incorporate varied, but stable, geomorphological conditions, should, by enhancing habitat diversity, increase fish biomass and species richness.

Demands on the resources of western rivers, such as land use, water quantity and quality, and habitat, are increasing. These increasing demands call for a broad, interdisciplinary approach to management of rivers and watersheds. The US Bureau of Reclamation, in partnership with the states of Arizona and New Mexico, Graham County, Arizona, and the San Carlos-Safford-Duncan Watershed Group, is conducting an interdisciplinary study of the hydraulics and fluvial geomorphology of the upper Gila River. The study will form the basis for future management by the stakeholders. The purpose of these technical analyses is to facilitate informed management decisions by stakeholders. River resource management is a complex and uncertain endeavor. This approach provides technical information in a sequence that allows stakeholders to proceed responsibly in the face of such uncertainty. It provides a sound alternative to "charging ahead blindly," "studying it to death," or being "paralyzed by indecision." Each of these can foreclose management options, and have substantial social, economic, and ecological effects.

Riparian forests have been shown to provide many important benefits to stream ecosystems. In urban watersheds, however, the ecological benefits of riparian restoration may be diminished due to widespread hydrologic and biogeochemical disturbance within the watershed. An integrated, multidisciplinary study is being conducted in southeastern Pennsylvania to assess the ecological benefits of riparian reforestation in urban watersheds. The study is based on comparisons of physical, chemical, and biological attributes in forested and non-forested sections of 12 streams with different levels of urban development within their watersheds. Results show a range differences in geomorphic, habitat, and biological attributes in forested versus non-forested stream reaches, and urban versus non-urban streams.

Sedimentation downstream of the confluence of the Bad and Missouri Rivers has increased water surface elevations near Pierre and Fort Pierre, South Dakota. Previous studies have confirmed that the increased water levels are due to a delta formation at the headwaters of Lake Sharpe. This paper presents the analyses of methods to increase sediment flushing, i.e., to move deposited sediments deeper into the reservoir. A calibrated and verified HEC-6T model is modified to assess the consequences of lowering pool elevations in Lake Sharpe. In addition, the existing model is modified to simulate, as much as possible, what effect the installation of a series of dikes would have on delta formation in the headwaters of the lake. The analyses make it apparent that lowering pool elevations is, in this case, more effective than Installing spur dikes in the headwaters of the reservoir. Lowering the pool elevation on the reservoir can significantly reduce the magnitude of the predicted increase in water surface elevations on the Missouri River over the simulation period. Spur dikes have a very localized effect, and augment the predicted increases in upstream water surface elevations.

The Tennessee Valley Authority (TVA) is enhancing water resources tools to examine water quality in the integrated river and power system. This paper describes the development and linkage of Norris and Melton Hill Reservoirs models using a two-dimensional hydrodynamic and water quality model, CE-QUAL-W2, linked with a one-dimensional hydrodynamic and water quality model, ADYN-RQUAL. The models were calibrated separately, then linked and calibrated as one model, using field data collected in 1997. This report documents a preliminary calibration for temperature and dissolved oxygen (DO). Overall, the model was reasonably calibrated.

The operations of four eastern New Mexico reservoirs on the Pecos River have historically been to the primary benefit of the agricultural water users. Current habitat restoration targets in portions of the river have led to the development of a water operations model to assess the impacts that modified operations have on instream flows, the agricultural water supply, and Pecos River Compact deliveries. The RiverWare river and reservoir routing application was used to develop a water operations model of the Pecos system, and the model was applied to assess the impact of changes in operations to enhance habitat for the federally threatened Pecos bluntnose shiner (Notropis simus pecosensis). Processes simulated in the model include irrigation diversions and return flows, reservoir seepage and evaporation, flood wave attenuation and translation, streambank storage, and losses of river flows due to evaporation, seepage, and evapotranspiration. Two model runs were compared to assess the impact of changed operations from November 1, 1998 through October 31, 1999. One scenario represented the actual operations that include fish bypasses to augment instream flows and another scenario represented operations based on a No Action condition. The two model simulations are presented with results and a review of the impacts of the changed operations.

In recent years, a new computer package called SAMS (Stochastic Analysis Modeling and Simulation) has been developed by Colorado State University with support from the US Bureau of Reclamation. As its name implies, SAMS provides a variety of capabilities in the areas of Stochastic Modeling, Analysis and Simulation. It is, in many respects, an expansion and an update of the widely used LAST stochastic hydrology package which was originally developed by Dr. William L. Lane of the Bureau of Reclamation in 1978 and 1979. The current version of the SAMS software is called SAMS 2000.

Steep-gradient streams present numerous challenges with respect to restoration techniques and numerical modeling. A new methodology is proposed for use as an approach to river restoration in hydraulically steep rivers. This approach utilizes the most current technology used in numerical modeling of river ecosystems to provide a quantitative as well as qualitative analysis of river flow, sediment transport, and geomorphology. The approach is applied to a case study on the Spokane River, a steep-gradient, bedrock-controlled river that flows through the City of Spokane in eastern Washington. This research utilizes two-dimensional modeling using the Finite Element Surface Water Modeling System computer program to develop a strategic plan for river restoration on the Spokane River. The research work that is the focus of this paper is the hydrodynamic component of the project. Hydrodynamic model results are used to identify and isolate areas of accelerated sediment erosion. Abbreviated research results (qualitative and quantitative) are presented for the two-year storm event flow in the Spokane River.

This paper presents a description of the GSTARS 3.0 model. The GSTARS 3.0 model, which is under development, is an evolution of the GSTARS 2.1 model to include phenomena associated with reservoir sedimentation, such as delta formation, turbidity currents, and the effects of flushing, sluicing, and dam removal. In this paper the GSTARS 3.0 model is presented with some detail. Preliminary test results are also shown. The GSTARS 3.0 will be released in late 2001 or early 2001.

Operational management of multiobjective river and reservoir systems is facilitated by RiverWare's operational policy modeling features. Rulebased simulation is solved by executing user-specified prioritized rules that are easily created, examined and modified in a syntax-directed graphical editor. The rulebased simulation run analysis utility shows exactly how each policy influenced releases, flows and elevations during the simulation. An optimization solution using pre-emptive linear goal programming is driven by a set of prioritized goals input by the user. Each goal is an objective or a set of constraints on the system; the goals are satisfied in priority order. The Optimization Analysis Tool shows how each goal influenced the optimal solution. Some applications of these tools to real-world problems are described by other papers in this session.

The principal purpose of a reservoir system is to provide inertia against variable inflows so as to make more profitable use of the water possible. The principal design factor to bring about this inertia is the storage of the reservoir. A second important factor is the operational management. Both define inertia a reservoir provides against variable inflows. Traditional optimization models are based on deriving a release policy that optimizes a given objective. Such approaches do not account for the fact that the release, which is a function of random inflow and thus a random variable itself, may have a distribution with different variance measure based on the available forecasts. Work is in progress to develop a mean-variance model within nonlinear optimization framework in desire to minimize variance of the objective to obtain robust (maximum return) operating policy.

The Edwards Aquifer is one of the most permeable and productive aquifers in the United States and serves as the sole source of water supply for more than 1.3 million people including the City of San Antonio, Texas. It is also the source of water for the two largest springs in the southwestern U.S., Comal Springs and San Marcos Springs in south-central Texas, which support a delicate and diverse ecosystem. The Edwards Aquifer Authority was given the responsibility in its enabling act (Senate Bill 1477, 73^rd Texas Legislature) to manage, conserve, preserve, and protect the Edwards Aquifer. Pursuant to this mandate, the Authority has commissioned a program of technical studies necessary to support and evaluate, aquifer management alternatives. This paper explores two of the numerous management strategies proposed by various investigators including the authors of this paper. These strategies, which incorporate the complexity of the aquifer and recognize the unique opportunities to optimize groundwater management, include recharge enhancement and redistribution of pumping. Optimization of Edwards Aquifer management will likely involve a combination of many proposed strategies operating on a temporal basis to support all of the beneficial users of the aquifer.

For the past several years, the Tennessee Valley Authority (TVA), U. S. Bureau of Reclamation (USBR), and the University of Colorado's Center for Advanced Decision Support for Water and Environmental Systems (CADSWES) have partnered to develop a software package called RiverWare for use in modeling multipurpose reservoir systems. RiverWare now offers three different modeling approaches: interactive simulation, rulebased simulation, and optimization. TVA implemented the interactive simulation software in April 1996 for scheduling both power and nonpower reservoirs in the TVA system. In May 2000, TVA implemented optimization modeling for scheduling the reservoir system. Prior to this, optimization modeling had been used in parallel with interactive simulation modeling in scheduling the system for about two years. The optimization modeling approach takes into account not only the power economics of the hydro system, but also other demands placed on the reservoir system. These demands, which include flood control, navigation, recreation, and water quality, as well as special operations for maintenance and community events, are defined in RiverWare as prioritized constraints. The optimization routine uses goal programming to satisfy all of the constraints in order of priority to the extent possible, and then with any remaining flexibility, optimizes hydropower operations to reduce the total integrated system power supply cost. Hydropower operations are optimized by maximizing the combined value of energy generated during the forecast period and water reserved in storage for future generation.

During calendar year 2000, the Secretary of the Department of the Interior (Secretary), acting through the Bureau of Reclamation (Reclamation), considered the adoption of specific interim surplus criteria under which surplus water would be declared in the lower Colorado River Basin during an interim period that would extend through 2016. An Environmental Impact Statement was prepared to discuss the specific alternatives under consideration and to identify the potential environmental effects of implementing such criteria. Potential hydrologic effects of the alternatives compared to baseline conditions were analyzed using Reclamation's long-term policy model, implemented in RiverWare, a general-purpose river and reservoir modeling framework. Using RiverWare's rule-based simulation option, each alternative was represented in a different rule set and used to direct the particular simulation. Multiple runs were made to quantify the uncertainty with respect to future inflow hydrology. The results were then used to quantify the comparative impacts on various resources, including recreation, fisheries, special-status species, and energy production. The work culminated in the selection of a preferred alternative and the Record of Decision, which was signed by the Secretary on January 16, 2001.

Large container ships approaching harbours via tidal rivers create strong currents and large ship waves. In the Elbe estuary near the Port of Hamburg with a tidal range of about 2,85 m the century old protection of the embankments show undulate shape even after frequent restoration. Analysis of the origin of the deformed embankment protections was done considering wind waves, ship waves and flow conditions from varying river discharges and tidal flows by using numerical and physical models which were calibrated with local field measurements. The river discharges vary between LQ = 145 m³/s and HQ = 3.620 m³/s at the gauge Neu Darchau. The analysis determines different reasons for the deformed protections. One reason is the construction of the embankment protection. Most embankments in the Hamburg harbour are protected with rubble or rip-rap protections. As the basement of the protection debris of destroyed buildings and quay structures are used. These are covered by loose granite stones. Another reason is the interaction of ship and wind induced waves, because even restored and redesigned embankment protections were deformed. The interaction processes were simulated with the numerical models SWAN and ODIFLOCS. The results were verified with physical models in a small towing tank of the FRANZIUS-Institute and field investigations.

The restoration of riparian forests has become a major focus of watershed initiatives throughout the United States. Concurrently, there is a growing interest in restoring streams in urban or urbanizing areas due to the increased pressures caused by rapid growth and urban sprawl. Unfortunately, a scientific basis for restoring urbanized streams currently does not exist. Riparian vegetation along streams has a significant impact on stream channel morphology, which in turn influences aquatic ecosystem structure and function. Additionally, watershed urbanization has a significant influence on channel morphology and aquatic habitat. Research results concerning the influence of watershed disturbance (urbanization) and riparian condition on fluvial morphology are presented. The implications these research results have on current stream restoration design and practice are highlighted.

In many areas of the world, utilities have pursued projects that utilize current water resources to plan for future droughts, to protect water resources, to recharge wellfields and/or to store water for use at a later point in time. The common thread of all of these technologies is the injection of vast amounts of treated or treatable water beneath the surface, rather than discharging it to rivers, reservoirs, oceans or other sources. Specifically, these technologies are termed Aquifer Reclamation, Artificial Aquifer Creation, Aquifer Recharge and Aquifer Storage and Recovery (or ASR). The first three offer the potential to use the rock formations to improve existing or potential wellfield withdrawal zones. The intent of ASR is as a management tool to deal with drought demands or significant fluctuations in seasonal demands where water is both injected at withdrawn a the same point. Because waters may remain limited, in some areas the use of alternative groundwater injection programs have been proposed or pursued to address these needs using waters of less than pristine (or impaired) quality, and mostly with limited success or significant resistance. The resistance is caused by the risk of effects to the public should these waters be recovered in water supply wells at a later point in time.

This paper discusses approaches to stable channel design that utilize sediment transport as a basis for quantifying channel stability. Fundamental methodologies sediment routing, sediment continuity, threshold and hydraulic geometry (regime) equations. The sensitivity of stable channel dimensions to sediment-related boundary conditions is explored for an urban channel in the Austin, TX area as a case study. Historically, urban channel design has focused on erosion control and flood conveyance, ignoring considerations of geomorphology and habitat sustainability. Sediment transport is often neglected in the design of channel stabilization and flood conveyance projects. In many cases avoidance of deposition can be just as important as avoidance of erosion. Stable channel design has traditionally included armor with large rock, gabions, and concrete. More recently bioengineering techniques have been utilized. Too frequently tactics are used to "control erosion" without a strategy that considers the fluvial processes of the system.

The CCHE1D model was designed to simulate long-term flow and sediment transport in channel networks to support the DEC project. It uses either the dynamic wave or the diffusive wave model to compute unsteady flows in channel networks with compound cross sections, taking into account the effects of in-stream hydraulic structures, such as culverts, weirs, drop structures, and bridge crossings. It simulates non-uniform sediment transport using a non-equilibrium approach, and calculates bank toe erosion and mass failure due to channel incision. The CCHE1D model decouples the flow and sediment transport calculations but couples the calculations of non-uniform sediment transport, bed changes and bed material sorting in order to enhance the numerical stability of the model. In this paper, the sensitivity of CCHE1D to parameters such as the non-equilibrium adaptation length of sediment transport and the mixing layer thickness is evaluated in cases of channel aggradation and degradation in laboratory flumes as well as in a natural channel network. In the case of channel degradation, the simulated scour process is not sensitive to variation in values of the non-equilibrium adaptation length, but the determination of the mixing layer thickness is important to the computations of the equilibrium scour depth and of the bed-material size distribution at the armoring layer. The simulated bed profiles in the case of channel aggradation and the calculated sediment yield in the case of natural channel network are insensitive to the prescription of both the non-equilibrium adaptation length and the mixing layer thickness. The CCHE1D model can provide reliable results even when these two parameters are given a wide range of values.

Planned modifications of William Cannon Drive in Austin, Texas, by the Texas Department of Transportation (TxDOT) and the City of Austin included the following changes: (1) raising the roadway to exceed an intended 25-year flood level; (2) building a new bridge over Onion Creek; (3) constructing a "relief opening" in the roadway embankment to provide greater floodflow passage and reduce water-surface elevations upstream of the crossing; and (4) building a new bridge over Marble Creek, a tributary of Onion Creek. One-dimensional floodplain models of the proposed construction indicated no significant upstream impact during the 100-year flood conditions. However, the Onion Creek floodplain is very complex, requiring significant assumptions and judgment to model the hydraulic conditions when using one-dimensional tools, such as HEC 2. Given the limitations of traditional one-dimensional tools in this application TxDOT decided that this project should be modeled using state-of-the-art two-dimensional floodplain modeling techniques.

The sequential nature of reservoir operating decisions and the variability of streamflow makes Stochastic Dynamic Programming an attractive optimization procedure for reservoir system operations. This paper examines the use of Sampling Stochastic Dynamic Programming (SSDP). SSDP models employing the National Weather Service's (NWS) Ensemble Streamflow Prediction (ESP) forecasts are compared to SSDP models based on historical streamflows and snowmelt volume forecasts. The SSDP optimization algorithm, which is driven by individual streamflow scenarios rather than a Markov description of streamflow probabilities, allows the ESP forecast traces to be employed intact, thus taking full advantage of their rich description of streamflow variability and the temporal and spatial inter-relationships captured within the traces.

Optimizing the operation of a system of reservoirs is a challenging problem. Dynamic Programming is a flexible optimization tool that can accommodate the stochastic and nonlinear nature of reservoir operation. However, for systems with a large number of state variables, e.g., a large number of reservoirs in a system and multiple forecasts on streamflow, the computational requirement of Dynamic Programming is prohibitive. A Regression Dynamic Programming approach is developed to efficiently solve stochastic and nonlinear models of reservoir control problems. Tile "curse of dimensionality" is alleviated using clever sampling schemes based on statistical methods of experimental design for state space representation. Furthermore, the optimal value function is efficiently approximated using penalized regression splines. Stochastic, multiple-reservoir control problems of two and seven dimensions are solved using the Regression Dynamic Programming approach.

The history of Mecklenburg County streams is not much different than other parts of North Carolina or North America for that matter. Man has caused great damage during the last 150 years because of riverine system alterations. Major initiatives in both Charlotte and Mecklenburg County Storm Water Services since 1993 are focused on numerous types of projects that integrate flood control, stream restoration, wetland creation, open space acquisition, structure demolition and water quality improvement. The challenge facing today's engineers and scientists includes resolving various community needs. As the leader in urban restoration efforts in the Southeast, Mecklenburg County has learned to balance these often-competing needs to produce successful projects.

The construction of a fluvial dock in the lower jungle of Peru is expected to create erosion problems. Removal of vegetation can induce the detachment of a thin topsoil layer where vegetation grows. Rainfall is very heavy and surface runoff can completely wipe out the nutrients, leaving it bare. On the other hand, modification of the river may cause the alteration of the river morphology. However, this is phenomenon is expected to be less intense. The solution has to be compatible with the construction methods used and also with the vegetation, materials, and labor available. The design approach is presented in this paper. Monitoring of the conditions is expected to be conducted during and after construction works.

Taiwan is a mountainous island nation, with more than 71 percent of its land area occupied by mountains or hills 100 meters or higher in elevation. Due to stability concerns, traditional river engineering work has always emphasized safe and practical, but not necessarily ecology or environment friendly, designs. In recent years, however, environmental awareness and the demand of outdoor recreation have risen rapidly. Large scaled river "beautification" projects have received considerable attention and many have been implemented. Examples include the Tongshan River Park in Illan County and several urban creeks around Taipei City. On the other hand, still relatively few projects are designed for maintaining ecological balance or habitat protection and restoration. In this paper, a brief description of the status of activities regarding "ecological engineering methods" in Taiwan is given. A case example, i.e., efforts made for saving the endangered Formosan Salmon is described, with emphasis on the quantification of the relationship between stream physical parameters and habitat requirements for the treasured fish. The Formosan Salmon (Oncorhynehus masou formosanus) is a landlocked species unique to Taiwan. Its habitat is now limited to a mountainous region in Central Taiwan. Due to human encroachment and deteriorated water quality, the Formosan Salmon population has declined over the years to less than 1,000. The government has since 1994 initiated major efforts to ensure its survival. The paper describes some of the most recent such efforts.

Recently, numerical models have been used more frequently in hydraulic design projects. This is particularly true in the design of fish passage facilities. Advances in numerical modeling methodologies and the ability to collect high-resolution position data of salmonids within a reservoir have led to interesting issues of numerical model calibration. Presently, more emphasis is being placed on higher-order hydrodynamics, such as accelerations, turbulence and energy dissipation. Therefore, it has become subsequently more important to understand the ability of a numerical model to predict such quantities accurately. The purpose of the paper is to describe the detailed approach taken to calibrate a fully three-dimensional numerical model of two main stem Columbia and Snake River dams, namely Rocky Reach Dam and Lower Granite Lock and Dam. The paper presents detailed calibration methods that show validation of the numerical model to field and physical model velocities; field measurements of velocity fluctuations due to unsteadiness as well as turbulence; and the effect of surface roughness. Additionally, data will be presented showing the impact of scaling factors and limitations of spatial boundaries from physical models used to provide validation data. The paper concludes by discussing the need for accepted standards for numerical model validation.

Unsteady flow models are being used more frequently to develop regulatory floodplains and floodways. However, there are additional technical issues to consider, particularly in relatively flat or tidal rivers, beyond those associated with the application of steady flow models. These issues include (1) the development of an appropriate upstream boundary condition, including the peak, volume, and hysteresis ("loop-rating") effects of the hydrographs, (2) the choice of time-varying or steady downstream boundary conditions, (3) the influence of time-varying processes in the river, such as tide-geometry interactions, (4) the availability and use of appropriate model calibration data, and (5) the development of floodways using unsteady flow models in complex river systems. An application of UNET to the Snohomish River in Washington State is used to illustrate some of the problems that can be encountered.

The authors propose a model to forecast streamflows, which utilizes the relationship found between El Niño - Southern Oscillation (ENSO) events and the streamflow of Colombian rivers. The relationship between ENSO and Colombian river discharges was explored by the authors in a previous study. Exceedence probability curves are developed using Linear Discriminant Analysis (LDA) and the ENSO indicators selected in the previous study. The exceedence probability curves are used to simulate five years of the streamflow series. Dynamic Programming (DP) is then utilized to develop reservoir operations policies. To illustrate the proposed model, the case study of the Nare River and the El Peñol Reservoir in Antioquia, Colombia, is presented.

Boone Reservoir receives municipal and industrial waste discharges from the surrounding communities including Johnson City, Bluff City, Elizabethton, and Bristol and several large industries. It also receives nutrient loads from nonpoint sources such as animal waste, urban runoff, failing septic tanks, and waste from houseboats. To predict water quality in Boone as the result of changes such as waste load reductions and reservoir operations, the existing 2-D Boone BETTER model was upgraded and updated with field data collected in 1984-1995. To estimate the nonpoint contributions from each of the local drainage areas encompassing the South Holston and Watauga arms, a basin accumulation-washoff model was developed and calibrated for Beaver Creek (South Holston arm) and Buffalo Creek (Watauga arm) using data collected during the 1997-1998 field study.

Digital elevation models (DEMs) are a useful data source for the automatic delineation of flow paths, sub watersheds and flow networks for hydrologic modeling. Digital representation of the flow network is central to distributed hydrologic models because it encodes the model element linkages through which flow is routed to the outlet. The scale (drainage density) of the flow network, used controls the scale of hillslope and channel model elements. Although field mapping is acknowledged as the most accurate way to determine channel networks and drainage density, it is often impractical, especially for large watersheds, and DEM derived flow networks then provide a useful surrogate for channel or valley networks. There are a variety of approaches to delineating flow networks, using different algorithms such as single (drainage to a single neighboring cell) and multiple (partitioning of flow between multiple neighboring cells) flow direction methods for the computation of contributing area and local identification of upwards curvature. The scale of the delineated network is sometimes controlled by a support area threshold, which may impose an arbitrary and spatially constant drainage density. This paper examines methods for the delineation of flow networks using grid DEMs. We examine the question of objective estimation of drainage density and describe a method based on terrain curvature that can accommodate spatially variable drainage density.

This research evaluated actions taken by auto dismantling facilities in the Los Angeles, California, region as part of required compliance with regulations for industrial storm water discharge. Eight years after California issued a General Permit for storm water under the National Pollutant Discharge Elimination System (NPDES), a large number of dismantlers have failed to recognize their duty to comply; about 20% of identified facilities do not appear to have notified regulating agencies of their intent to comply. The research then evaluated a sample of complying facilities. The research involved storm water sampling at a smaller number of case study facilities, and determined that a large proportion have measured constituents in discharges in concentrations exceeding U.S. guidelines for storm water—not an enforced requirement, because the regulations do not specify numerical effluent limits. Estimates of pollutant load contributed by the dismantling industry appear substantial.

The California Department of Transportation (Caltrans) has initiated a four to five-year study in two Districts (Los Angeles and San Diego, California) to examine the benefits, technical feasibility, costs and operation and maintenance requirements of retrofitting extended detention facilities into existing highway and related infrastructure. Five locations are being retrofitted with extended detention that have varying watershed areas and basin design parameters. Automated monitoring stations have been installed at each site upstream and downstream of the BMP to assess constituent removal. Constituents monitored in the runoff include: suspended solids (e.g., sediment), metals, nutrients, and organics (e.g., gasoline). Detailed records are also being kept for maintenance and operations requirements. To date the projects have been sited, designed, constructed and monitored (for three years). A Comprehensive operation and maintenance program is in place to ensure the detention basins operate at peak performance. Sampling results show average suspended solids removal was 73%, total metals removal varied between 61% and 75%, while dissolved metals removal varied between 16% and 44%. Removal was lowest for nutrients, especially nitrate, which was about 17%. The constituent removal efficiency for a concrete lined basin showed generally lower removal rates. A focus of the study is on determining the unique problems and solutions to those problems that occur with structural BMP retrofit relative to construction, operation and maintenance. Operation and maintenance requirements have been tracked. It appears that major maintenance of the basin (removal of sediment) will be required on average about every 10 years. Other program elements include vector monitoring and biological (endangered species) monitoring. This paper examines the feasibility of using detention for water quality enhancement for new construction, but with emphasis on retrofit construction, and design parameters that appear to enhance performance based on the field sampling results and the long-term operation and maintenance costs of this technology.

In this paper, we present an Internet-based, Bayesian Decision Network engine to aid watershed stakeholders in collaborative decision-making. Recent years have seen an increased emphasis on including all affected parties in the process of making water resources and water quality management decisions (as in the TMDL program). Given the complexity of the models and data analysis tools that are typically employed by engineers and scientists in watershed studies, meaningful communication with stakeholders can be a daunting task. In our experience, stakeholders are often skeptical of model and data analysis results because of the inherent uncertainty associated with these methods. Because of this, a stakeholder may be more likely to accept results presented in the form of a probability distribution of potential outcomes, than a single predicted result. Additionally, if model predictions are mapped into the likelihood of realizing tangible and intangible benefits, stakeholders have a means whereby to evaluate the anticipated results. Bayesian Decision Network (BDNs) are presented here as a useful tool for diagramming the decision process; for holding relationships between variables; and for analyzing the anticipated effects of management decisions while explicitly accounting for the associated uncertainties. An Internet-based application for employing BDNs in watershed decision-making is described with a demonstration application from the East Canyon watershed in Utah.

The flow and water quality process in the Chicago Waterway System (CWS) are very complex and critical water quality conditions may result under a wide range of flows. The Metropolitan Water Reclamation District of Greater Chicago (District) will soon be faced with a number of difficult water quality management problems including the impact of reduced discretionary diversions from Lake Michigan for water quality improvement in the summer, assessment of water quality impairment, and development of total maximum daily load allocations. A water quality model capable of simulating water quality processes under unsteady-state flow is being developed to assist water quality management and planning decision making. The CWS is a 122 kilometer (76-mile) network of navigable waterways controlled by hydraulic structures in which the majority of flow is treated sewage effluent. The dominant uses of the CWS are for commercial and recreational navigation and for urban drainage. Critical to the development of any water quality model is the adequacy of data for calibration and verification. Due to the complexity of the CWS, the District will increase the already extensive amount of quality and quantity data collected. The United States Geological Survey (USGS) has recently established discharge and stage gages at the three CWS inlet controls and has operated one near the outlet control for several years. In addition, four tributary stream inflows are gaged by the USGS and the District measures the treated effluent discharges at four water reclamation plant (WRP) outfalls.

The City of Charlottesville and the County of Albemarle, Virginia, are concerned about possible negative impacts of a proposed highway to be constructed adjacent to the community's primary source of drinking water. An evaluation of erosion and sediment control during road construction; increased pollution from stormwater runoff; and risk and ramifications of spills of hazardous and other chemicals of concern was performed. The proposed road project was evaluated considering control measures in place for the three categories of possible pollutants. The community must now reach a decision as to whether the highway can be constructed with an adequate level of water supply protection.

The increased application of constructed wetlands for stormwater management has created a demand for improved design recommendations. One aspect of effective design is with regard to the types of vegetation. The research presented in this report examines the relative pollutant removal capability for specific wetland vegetation. Monoculture stands of Typha spp., Scirpus spp., and Phragmites, spp. were tested in wetland treatment cells against an unvegetated control. Cells were subjected to four treatments reflecting three theoretical detention times of one week and two weeks at high and low pollutant concentrations. Cells were continually fed with synthetic stormwater containing TSS, TP, COD, Cu, and motor oil. Results of water quality analysis show various trends with respect to pollutant removal and time.

New methods are used to evaluate stormwater controls and Best Management Practices (BMPs) within a land development context. Costs are developed using published literature and standard cost estimation guides. A method is developed in which costs are determined for each parcel within a development for specific land uses. The effect of including the opportunity cost of land in the analysis is evaluated. Costs attributable to stormwater controls are allocated among purposes. A method is developed in which stormwater control costs are assigned at the parcel level. Data gaps and research needs are then explored in the context of addressing this complex problem.

Urbanization affects stormwater runoff. The effect is two-fold, increased runoff and degradation in water quality. A variety of methods are employed for the management of urban stormwater runoff. These include detention basins, wet ponds, infiltration beds and underground detention/retention chambers. Stormwater management regulations were initially developed to regulate the peak rates of runoff. Water quality was not a concern for some time. The regulations were later amended to include water quality. This paper presents an overview of design methodology of various stormwater management systems. It discusses shortcomings in design and recommends measures for improvements. The paper also describes differences in local and state stormwater management regulations in New Jersey and offers suggestions for unifying the regulations.

This research is designed to evaluate effectiveness of current regulations for control of pollutants in stormwater runoff from industrial facilities, and resulting efforts by the regulated community to reduce pollutants. For three targeted municipalities, the research first assesses the approximated proportion of industrial facilities that have recognized their duty to comply since the promulgation of permits under NPDES in the early 1990s. The research examines the proportion of facilities subject to regulations that have filed Notice of Intent (NOI) and the number of new NOIs filed each year since the regulations took effect in 1992. Then, the research determines for each municipality the industry types with the greatest number of NOIs filed. The purpose of these analyses is to characterize trends and patterns of compliance by industrial facilities within the regions, in order that future efforts may attempt to link those trends with observed water quality changes in the targeted municipalities. The total number of facilities in compliance can be influenced by unique facility types in different regions; by the diligence of regulatory and outreach effects by state and local agencies in different regions; and various other factors. The method is based on databases containing industrial facility compliance information. In this way, the research evaluates the relative effectiveness of municipal programs at achieving the pollutant reduction goals of the storm water NPDES regulations.

The purpose of the Iron Mountain-Kingsford Wastewater Treatment Facilities combined sewer overflow basin evaluation/study was to comply with NPDES Permit No 23205 and to determine (1) If the combined sewer overflow (CSO) retention basin meet Michigan Water Quality Standards at the time of discharge?; and (2) If the CSO basin provides adequate treatment of combined sewerage discharges? The goal of the CSO Basin study was to collect receiving water quality data to evaluate the impact of the treatment basin overflow on the Menominee River. Evaluation and reporting was accomplished by collecting water quality data from four combined sewer overflow discharges to the Menominee River and from river water quality monitoring locations upstream and downstream of the wastewater treatment facilities. This paper includes the results of the collection of water quality data from the Menominee River, and evaluates the CSO system performance relative to water quality standards. In stream monitoring of the Menominee River was utilized to establish site-specific conditions in receiving water during an after wet weather overflow events. This paper details analysis of both water quality sampling and the effects on the chemical characteristics of the river and flow volume quantities of the Menominee River, both during and after wet weather overflow events. The results of collecting, monitoring and entry of massive quantities of data and our professional evaluation of the CSO Basin performance are documented in this paper. This paper reviews the CSO Basin overflow events during 1997, and it demonstrates the water quality standards are not violated during overflow discharges to the Menominee River.

The present study monitored several ultra-urban BMPs: treatment manhole-type of structures such as the Stormceptor, a bioretention area, and the Vortechs Stormwater Treatment System, which is a chamber-type structure for a period of two years. A total of thirty storm events were sampled. Study period removal efficiencies (PRE) observed for the monitoring sites are as follows: Isoilater-Total suspended solids (TSS), 74%; Total phosphorus (TP), 33%; Chemical oxygen demand (COD), 70%; and Oil and Grease (O/G), 69%, Stormceptor - Total suspended solids (TSS), 57%; Total phosphorus (TP), 66%; Chemical oxygen demand (COD), 28%; Total nitrogen (TN), -27%; Copper (Cu), 22%; Zinc (Zn), 73%, and Oil and Grease (O/G), 33%, Bioretention area - TSS, 53%; TP, 13%; COD, 16%, and O/G, 66%, Vortechs - TSS, 27%; TP, 11%; COD, 24%; TN, 64%; Cu, 13%; Zn, 41%, and O/G, 6%. Sediment accumulations in the treatment manhole-type structures were monitored. Resuspension of sediment during large storm events is a concern for these BMPs. A cost analysis showed that the bioretention area might be the most cost-effective in terms of cost per unit pollutant removal. However, the bioretention area may export pollutants such as sediment before the soil-plant system stabilizes.

Stormwater is now receiving attention from regulatory agencies and has become an important component in watershed planning. In many cases, pollutant mass emissions from stormwater exceed those from wastewater treatment plants. Land use has been identified as an important parameter in predicting stormwater quality. Land uses associated with vehicular activity, such as parking lots, are thought to be high contributors of stormwater pollutants. Other factors, such as greater pollutant concentrations or mass emissions at the onset of rainfall, usually called a "first flush," or higher emissions from the first storm of the season, usually called a "seasonal first flush," have been identified. In order to determine the magnitude of the first flush from freeway runoff, three sites in the west Los Angeles area were sampled for 14 storms during the 1999–2000 rainy season. Samples were collected very early in the storm in order to compare water quality from the first runoff to water quality from the middle of the storm. A large range of water quality parameters and metals were analyzed. The data show large first flushes in concentration profiles and moderate first flushes in mass emission rates.

Grated gutter inlets are commonly used for pavement drainage along roadway embankments and on graded approaches to overpasses. This inlet style is installed in a gutter without substantial curb and covered by a shallow V-shaped grate conforming to the gutter profile. The study reported here concerns a particular design common to Florida (Florida Department of Transportation, Index 220, Type S). Tests were conducted for two grate configurations using a one-half scale model on longitudinal slopes ranging from 0.8% to 8%. Hydraulic performance was gauged by measuring inlet capture as a fraction of total approach flow. Inlet flow was also correlated with measurements of normal depth in the gutter upstream. Mechanisms leading to bypass flow were examined as limitations to efficient hydraulic performance. Performance correlations for design are presented.

A wet-detention pond, constructed to treat agricultural runoff from winter vegetables, was studied to document constituent concentrations, measure hydrology, and analyze processes taking place. During the three years of study (70 rain events), the highest concentrations for potentially toxic metals entered the pond during five El Niño storms in 1998; and since higher pollutant loads are often more easily reduced these conditions contributed to the greater percent reduction of metal concentrations in 1998. The lowest constituent concentrations and storm runoff occurred during 1999, a dry year, when many of the fields were left fallow. Concentrations and volumes increased in 2000 caused, in part, by increased irrigation raising the surrounding water table. Although the concentration of at least seven metals failed to meet marine water quality standards at the inflow, only iron and copper failed to meet standards at the outflow, even though, their concentrations had been considerably reduced. Organic nitrogen had the poorest concentration removal since many nitrogen transformations in the pond actually increase organic nutrients. Total phosphorus levels were measured at high average concentrations of about 1 mg/L at the inflow.

In 1997 a group of investigators at Virginia Tech initiated a study, funded by the USEPA, to develop procedures for integrated assessment of environmental, economic, and biological impacts of alternate land development scenarios. The Upper Roanoke River Watershed (URRW) in southwest Virginia was chosen as the case study watershed. HSPF was selected as the hydrologic model because of its widespread use in evaluation of the hydrologic impacts of land use change. The model was applied to a 145 km² (56 mi²) sub-watershed (Back Creek) of the URRW. Four different development tracts (i.e. high density, medium density cluster, medium density conventional, and low density) were defined for creating various hypothetical scenarios of residential development, both with and without a network of primary and secondary roads. Continuous hydrologic simulation was performed using data for water years 1995–1998 to investigate the hydrologic effects of various spatial arrangements of development, measured in terms of effects on various error statistics. The entire effort was aided by the development of a macro-based scenario generator that partially automated the analysis of development scenarios.

Development projects in the high-altitude mountain environment of the Rocky Mountains often require innovative best management practices (BMPs) due to challenging runoff conditions, the relatively short growing season, vegetation and wildlife habitat considerations, and the high level of water quality of receiving waters. This paper discusses the unique challenges of development in the mountain region of Colorado and describes a variety of BMPs and stormwater/dewatering discharge management strategies that have been successfully employed on development projects. Case studies are presented of approaches for addressing runoff from snowmelt; shallow groundwater; soil erodibility, mobilization, and suspension; water chemistry; and regulatory requirements related to water quality and wetlands protection. These case studies provide examples of structural BMPs including an integrated treatment system for stormwater runoff and construction dewatering discharges utilizing multi-stage treatment, including alum-polymer addition for enhancing sedimentation of fine suspended clay particles. As an example of a state-of-the-technology non-structural BMP, the Town of Silverthorne, Colorado's Waterbody, Wetland, and Riparian Protection Regulations is examined. These regulations, which were adopted in 1999, are intended to protect the beneficial functions and values of wetlands through requiring a buffer zone around all waterbodies, wetlands, and riparian areas, ranging in width from 7.6 to 38 meters (25 to 125 feet) depending on implementation of BMPs and buffer zone functions. One of the first large development projects in Silverthorne to come under these regulations, the 3-Peaks Golf Course and residential development, is examined to illustrate application of these new regulations.

New York Harbor and its tributaries form a complex hydrologic network of open waters, embayments, rivers, estuaries, wetlands and riparian areas. The New York State classifications of many of these waterbodies may not be considered to meet the "fishable/swimmable" criteria of the Clean Water Act. Even so, current water quality standards, although lower than fishable/swimmable requirements, are still not attained in many locations throughout the harbor and its tributaries. The New York City Department of Environmental Protection (DEP) is executing a multi-phase program to address the impacts of combined sewer overflows (CSOs) and wastewater treatment plants (WWTPs) on these waterbodies in its efforts to maintain and improve water quality in the harbor and its environs. DEP's Use and Standards Attainment (USA) Project was launched in August 1999 to extend these efforts by employing a watershed-based approach to conduct an integrated evaluation of the interdependent factors affecting receiving water uses, including storm water, CSOs, wastewater treatment, upland uses, shoreline uses, habitats, sediment and water quality, with the active participation of major stakeholders from the start of the process. This project is playing an integral part in DEP's efforts to comply with the Clean Water Act while addressing ongoing compliance issues and Total Maximum Daily Load (TMDL) developments. This paper provides information on some of the methods employed and preliminary conclusions drawn by DEP to assess compliance with designated uses and water quality standards.

The Solids Transport and Deposition Study (STDS) was designed to characterize the rates and patterns of solids transfer to, and the collection within, storm water drain inlets located along Caltrans highway facilities. Litter, vegetation and sediment accumulations in 72 drain inlets in the Los Angeles area were monitored biweekly for a year. Sediment samples were collected monthly and analyzed for copper, lead, zinc, chromium, total extractable petroleum hydrocarbons (TEPH), total petroleum hydrocarbons (gasoline range) and BTEX. The primary study objective was to determine if certain distinguishable site characteristics, or factors, controlled the transport and deposition of sediment, metals, vegetation, litter, and petroleum hydrocarbons to highway drain inlets. The factors included in tile study were erosion control/sediment loading (vegetation factor), litter management (litter factor), toxic pollutant generation potential (adjacent land use factor), and roadway design (design factor). Analysis of variance (ANOVA) was the primary statistical method. The ANOVA results indicated that the four primary factors likely had little overall control on solids accumulation or metals mass accumulation, although roadway design and litter management were possibly important in some cases. Additional analyses indicated that other external factors (not included in the study design) were probably also contributing to solids accumulation and metals mass accumulation. This study is considered a first step in characterizing the important factors controlling solids accumulation in highway drain inlets.

This paper presents a comprehensive watershed management plan for the Jordan. Brook watershed, a 21.2 square-kilometer (8.2 square-mile) coastal watershed located in a developing area of southeastern Connecticut on Long Island Sound. The plan provides a consistent framework for evaluating and controlling impacts to wetlands and watercourses from development in the watershed. The watershed management plan includes a baseline assessment of wetland resources throughout the watershed to identify particularly high value wetlands and wetlands which require special levels of protection. The recommended plan consists of five major components including stormwater quality controls, upland protection zones for wetlands and watercourses, groundwater recharge and peak flow requirements, open space protection, and water quality monitoring. A multi-tiered framework is recommended for determining the level of stormwater quality controls required for development projects in order to protect downstream receiving waters and wetlands. The recommended watershed management plan provides a framework which could be applied in other municipalities, especially those affected by EPA's recently promulgated Stormwater Phase II regulations.

A number of laboratory tests were conducted to evaluate the efficiency of a proposed rockfill dyke in trapping suspended sediments in seepage flow subjected to low gradient conditions. This testing was part of a project to design a tailings containment facility to be built in a large lake in Canada. The sediment trap efficiency is an important input parameter for designing the tailings confinement system and determining the need for a sand filter on the inside (tailings and pond side) face of the dyke. The scope of the laboratory testing consisted of a number of sediment trap efficiency tests for coarse rockfill, fine rockfill, gravel rockfill and tailings sand. Two types of effluent, with and without flocculation, were tested in the laboratory, to simulate these possible operating conditions in the field. The laboratory facility was set up to simulate a conservatively high seepage flow condition across the proposed tail!rigs containment dyke. The experimental results showed that the process of sediment trapping in tailings sand is different from that in rockfill. Suspended sediment in seepage flow is trapped in tailings sand by the process of filtration, whereas in rockfill, sediment trapping occurs as a result of suspended particles settling in rockfill voids.

Over the past decade, Leon County has made several significant steps toward the development and implementation of major restoration plans for Lake Munson and its primary tributary, Munson Slough. Lake Munson, a 255-acre cypress rimmed lake, has been catastrophically damaged by more than a half century of municipal wastewater discharges, ditching, urban stormwater runoff, and industrial discharge. In fact, in 1982 the State of Florida designated the lake as the seventh most degraded in all of Florida. As a result, recreational uses of Lake Munson have diminished due to a drastic decline in water quality, loss of the fishery, and massive sedimentation. Camp Dresser & McKee Inc. (CDM) teamed with Leon County to design system improvements and provide construction oversight for this multi-phased restoration project. With the design efforts complete in December 1998, construction of the Phase I improvements began in December 1999. Components of this phase include treating stormwater runoff upstream from Lake Munson, reestablishing Munson Slough, removing of the large sediment delta from Lake Munson, and the removing of the trash and debris from the entire system. In conjunction with these efforts, Leon County has joined in discussions with several state and federal agencies to begin planning Phase II, which will include in-lake dredging. Overall, these improvements will provide the surrounding area with improved water quality and ecological functions of the lake, slough and downstream waters, in addition to restoring fishery and recreational opportunities.

Low Impact Development (LID) is an innovative technology, which combines a hydrologically functional site design with pollution prevention measures to compensate for land development impacts on receiving waters. LID is being demonstrated to be very effective for new and urbanizing areas. Some of the fundamental principles of LID technology, specifically the source control approach and the use of micro-scale control techniques have the potential to provide substantial benefits for the stormwater quality retrofits in existing ultra urban areas. This paper provides a preliminary assessment of the potential application of LID technology to ultra urban areas. It describes the hydrologic characteristics of ultra urban areas and relates these to identified stormwater management goals and objectives in ultra urban areas. Also potential LID strategies and techniques, which can be applied in these areas, are identified and described.

Section 303(d) of the Clean Water Act and EPA's Water Quality Planning and Management Regulations (40 CFR Part 130) require states to develop total maximum daily loads (TMDLs) for their water bodies that are not meeting designated uses under technology-based controls for pollution. The TMDL process establishes the allowable loadings of pollutants or other quantifiable parameters for a water body based on the relationship between pollution sources and in-stream water quality conditions. This method exists so that states can establish water-quality based controls to reduce pollution from both point and non-point sources and restore and maintain the quality of their water resources. This paper presents a methodology for characterizing TMDLs for pH impaired streams that characterizes the pH impact in terms of an associated hydrogen ion load. Because pH and an equivalent ion load can be related as a function of discharge and ionic strength, a functional relationship can be developed between discharge and the associated ion loading for a given pH value. By specifying a minimum pH value (e.g. 6) and a minimum activity correction factor, an envelope of maximum ion loads may be obtained as a function of discharge. By identifying a critical discharge for a given watershed, the maximum hydrogen ion load and associated TMDL can be obtained. Determination of the associated ion load reduction can further be accomplished by developing functional relationships between measured discharges and measured ion loads for a given watershed. The proposed approach has been applied to several watersheds in the state of Kentucky and was recently accepted by EPA Region IV as an acceptable protocol for pH TMDLs.

This paper in the proceedings represents, describes, and gives a background to a poster to be presented in the conference. The work is part of an ongoing research, in progress at the time of writing this paper, and the results will be presented in the poster. A Dynamic Watershed Simulation Model (DWSM) is being developed at the Illinois State Water Survey to simulate surface and subsurface storm water runoff, propagation of flood waves, soil erosion, and transport of sediment and agricultural chemicals in agricultural and rural watersheds. Different components of the DWSM have been applied to watersheds in Illinois for testing these components and assisting local watershed planning groups in planning restoration projects. Some of the recent progress made in this ongoing modeling study is presented in this conference. Testing (calibration and verification) of the DWSM-hydrology and sediment components on the 100-square-kilometer Big Ditch watershed in Illinois along with some scaling effect analyses are presented in a companion paper. Testing of the DWSM-agricultural chemical transport component on this watershed is in progress. Up-to-date results from these testing will be presented in the poster associated with this paper. Brief descriptions of the DWSM-agricultural chemical transport component, its earlier applications and testing on laboratory boxes and experimental plots and agricultural fields, the Big Ditch watershed, some of the environmental problems associated with this watershed, and past and ongoing studies of this watershed are presented in this proceeding paper.

The Cannonsville Reservoir, which serves as a source of drinking water to New York City, has been under a ‘phosphorous-loading restriction' due to the high phosphorus concentrations within the water body. These high concentrations are attributed to the non-point source loads from the agricultural land in the basin. Currently, the county is attempting the implementation of Best Management Practices (BMPs) in certain areas to abate this pollution problem. However, the county and regulatory agencies need a way to evaluate the effectiveness of the BMPs. In addition, it would be useful to have tool to project future conditions of the reservoir resulting from changing land use practices and BMPs. The approach of the evaluation of the BMPs and land use practices is to adapt a basin-wide watershed model for the Cannonsville Basin. The model simulates hydrology, sediment, and phosphorous transport throughout the watershed, which ultimately becomes an input to the reservoir. The model being applied is the Soil and Water Assessment Tool (SWAT), which was developed in Texas for use on agricultural lands. This model, which will be combined with Geographical Information Systems (GIS), is spatially distributed, requiring that the entire basin be divided into smaller sub-basins of similar land use, soil properties, and topography. The model uses this information, along with meteorological data, river geometry information, and constituent parameters to develop the fate and transport of phosphorus and sediment over the land surface. This paper will describe the calibration of the model for hydrology, suspended sediments, and phosphorus. In addition, it will discuss the use of the model in evaluating ‘future scenarios' regarding basin-wide BMP implementation.

The development of the Nitrate Total Maximum Daily Load (TMDL) for the Muddy Creek/Dry River watershed in Virginia illustrates important factors leading to successful completion and approval of a TMDL, while also revealing limitations to effective, accurate water quality management within the TMDL program. The Muddy Creek/Dry River watershed, which supports intensive agriculture, has experienced nitrate degradation in both surface water and groundwater. For the TMDL development, the HSPF watershed model was used to describe the nitrogen cycling and transport at the watershed-scale. Load allocation, which was based on total nitrogen loads, was complicated due to multiple significant sources, including effluent from a poultry processing facility, cattle pasturelands and loafing areas, and land applications of poultry litter and cattle manure. Critical to the ultimate success of this study was the willingness of the lead technical analysts from the University of Virginia and the state representatives to meet repeatedly with community representatives and to accommodate the unique character of this Mennonite-dominated agricultural community. A matrix of potential, feasible load allocation scenarios was presented to the community, from which they selected a recommended plan. While a TMDL allocation was successfully approved at the community, State and federal levels, several aspects of the TMDL program negatively impacted the study. First with litigation forcing rushed completion of TMDL's, the TMDL program's focus on meeting surface water standards subverted comprehensive management of water quality in the watershed. The significant groundwater impairments were not effectively addressed. Secondly, state water quality standards, which are often used both as measures of impairment and as target levels for the TMDL's are not always consistent with these uses.

The performance of Drain Inlet Inserts (Fossil Filter and StreamGuard in treating runoff from three California Department of Transportation (Caltrans) maintenance stations was evaluated as part of the Best Management Practice (BMP) Retrofit Pilot Program. Additionally, the effectiveness of an oil/water separator was evaluated at one Caltrans maintenance station. The study included 1) retrofitting the structural BMPs in existing maintenance stations and documenting those costs; 2) estimating percent pollutant removal efficiencies; 3) assessing the causes and frequency of flow bypass; and 4) documenting the type and level of effort required to maintain the structural BMPs. Drain Inlet Insert results to date show that reductions in metals, hydrocarbons, and solids are consistent with expectations for the technology; however, frequent flow bypass required more maintenance than anticipated. Oil/water separator results show no discernable difference between influent and effluent hydrocarbon concentrations at the low levels measured.

Field experiments on vegetative filter strips (VFS) showed average sediment-removal efficiency varied from 50 to 98% as flowpath length (i.e. width of the VFS) increased from 2.44 to 19.52 m. Almost all of the easily removable aggregates (i.e. aggregates larger that 40 μm in diameter) can be captured within the first five meters of the filter strip. However, the remaining small-size aggregates are very difficult to remove by filtering flow through grass media, as even relatively low levels of turbulent energy in the water is sufficient to keep the finer sediments in suspension. The only effective mechanism for removal of small-size sediments is infiltration. Experiments with low to moderate flow rates on the longer plot lengths showed removal efficiencies of 90% or higher. The sediment removal efficiency of the filter strip does not increase much by increasing the width of the filter strip beyond ten meters. Improved efficiency of VFS can be achieved through the installation of a drainage system (e.g. a French drain) to increase infiltration and by stem-reinforcement of vegetation with various geosynthetic products to reduce channelization of flow and short-circuiting.

As development occurs and impervious surfaces increase, we are faced with not just an increase in stormwater peak rates, but a tremendous increase in the amount of stormwater volume generated. Traditional methods of stormwater management, such as detention, often fail to address stormwater volumes. At the same time, infiltration to groundwater and recharge to the aquifers is decreased by the impervious surfaces and our practice of collecting and conveying water downstream. The impacts on streams are dramatic. During non-storm periods, baseflow is reduced and streamflow diminishes, but during even moderate rainfall events, streams in developing watersheds can quickly overtop their banks, causing localized flooding. The physical changes in the stream channel can cause loss of habitat and loss of biological diversity. Stormwater runoff is the primary cause of impairment in many urban streams. Sustainable stormwater management requires that we address not just peak rates but the increased volume of runoff, and that we attempt to mimic the natural hydrologic balance that existed before development. Design approaches and infiltration methods are the most effective means to do this, but require a change in approach to site development. In this paper, we will present a number of stormwater infiltration methods, and discuss their design and application on specific projects, including a number of installations of porous bituminous pavement that have been performing effectively for almost twenty years. We will also present applications of infiltration meadows, trenches, swales, porous concrete sidewalks, bioretention gardens, and other approaches. The design, installation, and performance of these methods at actual sites will be discussed, as well as "lessons learned" and the effectiveness of infiltration methods in reducing non-point source pollution.

Sand filters are a common stormwater treatment technology in a few areas of the country, but have had limited application in California and other areas. In an effort to better understand the cost, maintenance requirements, and pollutant removal ability of sand filters, the California Department of Transportation constructed five Austin style and one Delaware style sand filters in the Los Angeles and San Diego metropolitan areas. The sand filters were constructed as retrofit projects for maintenance yards, and park and rides. Each of these facilities includes stormwater monitoring equipment for collection of flow weighted composite samples. In addition, detailed records are being compiled of the design elements, construction costs, and type and amount of maintenance required at each of the facilities. This comprehensive assessment facilitates a thorough evaluation of the cost/benefit ratio, and technical feasibility for widespread implementation as part of Caltrans' stormwater management program.

Interest in reducing erosion from disturbed lands has increased in recent years due to the promulgation of the National Pollutant Discharge Elimination System (NPDES) Phase II program. This paper summarizes the results of hillslope erosion testing conducted at the American Excelsior Company's ErosionLab Rainfall Erosion Facility (REF). Soil loss rates were determined for hillslope plots using three different soil types (sand, loam, and clay). The framework within which the data from this study is analyzed and interpreted is based on the Revised Universal Soil Loss Equation (RUSLE). A primary goal of this research effort is to establish the numerical value of the soil-erodibility factor "K," used in RUSLE, for each of the three soil types. Baseline soil loss rates thus established are then used to quantify the effectiveness of a variety of erosion and sediment control best management practices (BMPs). In particular, surface protection treatments consisting of blown straw and a manufactured biodegradable erosion control blanket were examined.

The City of San Antonio, Texas (COSA) has endured significant flooding problems in the past, including several large events that occurred in the past few years. In an effort to reduce their recurring flood losses, the City has initiated a watershed-based program to use regional stormwater detention facilities. The City anticipates that this new program will provide an attractive alternative to using only on-site detention facilities throughout their metropolitan areas. In selected locations, the City also wants to develop multi-objective facilities that also provide recreational, water quality, certain flood-tolerant commercial uses, and/or other benefits. The rapidly developing Leon Creek watershed is located in the western portion of the San Antonio area. The lower watershed area includes densely developed areas as well as the Lackland and Kelly Air Force Bases. Presently, the upstream portion of the watershed is more rural but development pressures are increasing as growth moves radially outward from the central City area.

Home to the first of Henry Ford's assembly plants, the Ford Rouge Center in Dearborn, MI, has been in operation for eighty-three years. The six hundred and forty acre complex was originally designed to handle automobile production from raw materials through completed product. Located on the banks of the severely degraded Rouge River, the complex is undergoing dramatic revitalization, including substantial redevelopment of the existing plant structures and the addition of several new trade buildings. The goal of the project is to transform a 20th century industrial icon into a model of 21st century sustainable manufacturing that will set the standard for the next century. Beyond the manufacturing aspects, Ford Motor Company has committed significant resources to improving and sustaining the environment as part of the rehabilitation project. Through a project called Heritage 2000, Cahill Associates (CA), was brought on site as environmental engineers for water resource leadership, through a team compiled by William McDonough & Partners Architects (WMP). Traditional stormwater management has focused on conveyance and discharge with emphasis on quantity for flood and peak rate control. More recent research by government, academic, and other groups has focused on the effects of stormwater runoff including pollutant loading and the influence on natural channel ecology and dynamics. New federal, state and local regulations based on this research have changed the focus from merely quantity to both quality and quantity of this regulated discharge. Cahill Associates with WMP has developed a stormwater master plan providing the facility with onsite stormwater storage and water quality improvement for smaller more frequent storms.

Stormwater wetlands are fast replacing detention ponds as one of the key mechanisms to reduce nonpoint source pollutant loadings. These Best Management Practices focus on smaller storms, encouraging long retention times and contact with vegetation to remove pollutants, design elements not considered for detention basins. The author suspects that traditional storage - indication routing may not be appropriate for stormwater wetlands, especially for smaller water quality storms. In order to evaluate this premise, the author has instrumented a recently constructed stormwater wetland, collecting flow and rainfall data. This data is being used for comparison with watershed models employing both hydrologic and hydraulic routing techniques. The models used for the study are HEC-HMS and a beta copy of the unsteady version of HEC-RAS. Initial results verify this concern and validate a need to continue and expand the study.

Lake Pontchartrain was a valuable recreational resource used widely by the surrounding communities until 1985 when the Louisiana Department of Health and Hospitals (LDHH) issued an advisory stating that the lake was a potential health hazard and, thus, unsuitable for swimming and other primary contact recreation. Today, this advisory is still in effect for the south shore area of the lake in Orleans Parish. The suspected source of the contamination in this area is urban stormwater runoff discharged to the lake via a system of stormwater sewers, pump stations and drainage canals. It is believed that the effluent is contaminated by sanitary sewer cross-flows.

For the last 8 years, the Brevard County Surface Water Improvement Program has used baffle boxes for stormwater sedimentation control at over 34 locations. As part of a Florida Department of Environmental Protection Demonstration Project for Indialantic Area Baffle Boxes, two baffle boxes were constructed in series on a 9.75 ha (24.1 ac) drainage basin in Sunset Park, near Indialantic. The first baffle box was installed in 1992 and long-term cleanout records have been documented on the performance of this baffle box. A second baffle box was installed in 1998 immediately upstream of the first baffle box to create a series configuration. Autosampler monitoring results for TSS, Total Phosphorus, COD, and BOD removal efficiencies are presented in this report for the second baffle box. In addition, the effectiveness of two baffle boxes in series is examined.

In developing countries today, over one billion people lack access to safe drinking water, and nearly twice as many live in areas without adequate wastewater collection and treatment. Numerous efforts by industrialized countries and their agencies [such as USAID, Asian Development Bank (ADB), the World Bank, and the UK Department for International Development (DFID)] attempt to provide technology and expertise to develop and build basic water and wastewater treatment infrastructure in developing countries. While the industrialized world is striving to develop water and wastewater infrastructure in developing countries, we must be mindful of the fact that effective management of those assets is the only way to ensure long term success. One of the ways the developed countries can aid in developing professional and efficient management of the infrastructure is through sharing lessons learned through the maturing of our water industry. SPBNET.Africa and The World Bank's Start-Up Kit are two leading efforts to bring benchmarking to the global water industry in the hopes of facilitating that effective management.

The establishment of Total Maximum Daily Loads (TMDL) for contaminants entering water bodies requires the development of suitable methods for contaminant measurement. In an effort to assess quantities of suspended-sediment transport, an acoustic device is being developed in a collaborative effort between the University of Mississippi's National Center for Physical Acoustics and the Department of Civil Engineering along with the USDA-ARS National Sedimentation Laboratory with support from the National Science Foundation. The acoustic device will be non-intrusive, automatic, and provide suspended-sediment concentration and particle-size information at many points throughout the flow depth in a short time period. In order to test the new acoustic device, validation against an established measurement method is necessary. Due to the properties of the acoustic technique, this validation cannot be performed by sampling directly beneath the device. Towards this end, a laboratory flume with a sediment-starved bed was used to establish whether laterally separated samples collected simultaneously at like elevations within the flow would have similar concentrations. It was found that the average error, after a constant correction was applied, was 6%. This was deemed acceptable for use in instrument testing. Starved bed results are compared with previously collected data in dune and upper-stage plane bed regimes, demonstrating the profound effect of a mobile bed on the accuracy of suspended-sediment sampling.

The development of fossil power generation facilities in the United States and abroad presents challenges with regard to site drainage and storm water management. Some of these challenges result from the facility location, while others are associated with local regulations. This paper discusses some of the storm water management challenges in power generation facility development and presents approaches that can be used to meet them. Techniques that have proven successful in managing storm water from fossil power plants are presented and described. Rainfall-runoff modeling techniques used to analyze and design storm water management facilities are also discussed.

Loading of Dissolved Organic Carbon (DOC) through storm runoff from parking lots is a significant, yet relatively neglected, source of elevated DOC concentration in urban streams during storm events. This study investigated DOC transport and loading from an paved parking lot during rainstorm events in order to elucidate impacts of the stormwater runoff on the chemistry of an urban stream. Water samples were collected from a drain in the parking lot of a shopping mall during 14 selected rainstorm events in 1999–2000. DOC concentration analysis was performed using a TOC analyzer. Measurements of DOC from the parking lot showed that period between storms and the precipitation intensity control the maximum DOC concentration (C_{DOC, max}) and the time required to reach C_{DOC, max} (τ_{DOC, max}), respectively. DOC loading from the parking lot was also estimated. The results can be valuable for prediction of DOC loads to urban streams.

Five field tests were conducted to evaluate the effectiveness of the Storm and Groundwater Enhancement System (SAGES) device for removing contaminants from stormwater. The SAGES device is a three-stage filtering system that could be used as a best management practice (BMP) retrofit to existing catchbasins/stormwater inlets or installed as a BMP for new construction. Stormwater is filtered and then discharged as it flows through three separate filtering sacks consisting of gravel on top, sand in the middle, and granulated activated carbon on the bottom. The tests employed two SAGES devices that were set up side-by-side. Both devices were constructed according to the vendor's specifications; one used a standard catchbasin, the second used a modified catchbasin filled with peat and wood chips. The tests were conducted so that a comparison could be made between the effectiveness of the two catchbasin configurations to remove stormwater contaminants. Water runoff from an asphalt parking lot during simulated rain events was utilized for the filtration tests. Particular attention was focused on the effects of variances of elevation head and influent suspended solids (SS) concentration on each configuration. The tests were performed by Battelle, Columbus, OH, under EPA Contract No. 68-C7-0008. The results of the testing showed that the highest removal efficiencies were demonstrated with elevated influent SS concentrations. Washout from the modified catchbasin appeared to contribute to increased effluent SS concentrations that clogged the SAGES filter sacks.

The paper describes a consorted effort by the Taiwan Water Resources Bureau, the City of Taipei, and the Bureau of Fei-tsui Reservoir Management in the protection of the water quality of the Fei-Tsui Reservoir. The Reservoir, with a watershed area of 303 square kilometers, is the major source of water supply for over 2 million people in the Metropolitan Area of Taipei. Over the years the Reservoir has suffered from siltation and more recently, from eutrophication. The sources of the pollution are traced to the hundreds of tea gardens, rice fields and other agricultural areas in the watershed. Large amounts of nutrients enter the reservoir by way of stormwater runoff during storm or typhoon events. The steep terrain and loose soil add to the problems. Since 1999 the various responsible agencies have worked to initiate an effort for implementing control measures to reduce nonpoint pollution in the Fei-tsui Reservoir Watershed. Practices being considered include non-structural measures such as nutrient management, and structural measures such as swales, detention basins, and wetlands, in addition to erosion and sediment control methods. A number of field tests have been completed on the performance of certain selected BMPs. A strategy for implementing the BMPs at the watershed scale is being developed, which is reported in the paper.

Total Maximum Daily Load (TMDL) developments for the nations impaired streams have become a major focus of activity over the past few years. This concept encompasses the determination of the Load Capacity (LC) of a stream and the associated Waste Load Allocation (WLA) for point and Load Allocation (LA) for non-point source pollutants. Even though guidelines exist and continue to be expanded and changed EPA is not very specific of how the components of the TMDL need to be determined, which has left much of the development at the discretion of the responsible agencies. As a result many different approaches exist to comply with the objectives of an acceptable TMDL. One of these objectives is to ensure the use of state of the art science, while another demands equity among the discharges. It is therefore imperative to include a framework that allows optimization as the omission of the latter causes excess costs that otherwise could potentially be reduced. This paper presents a methodology to effectively compute sensitivities that can be used at a later state to develop an efficient WLA procedure in for the case of CBOD/DO load scenarios. Sensitivities for steady state and unsteady flow scenarios are presented. It is shown that using a 2-dimensional dynamic modeling approach permits identification of a large number of temporally distributed sensitivities for sources along a highly dynamic estuary.

The overall objective of this study was to evaluate the feasibility of using low-cost natural filter materials for stormwater (SW) treatment. Generic mulch, pine bark mulch, and processed jute were evaluated for metal and organic pollutant removal from actual SW samples collected from a "hot-spot" (commercial parking lot) site in New Jersey. The retention and release behavior of pollutants in different filter materials was evaluated using a specially constructed bench-scale filtration apparatus which allowed for the simultaneous testing of up to ten different media conditions. SW flowrates (fluxes) through the individual columns as well as the sorption capacity of each filter medium were studied under a wide variety of conditions The benefits of combining mulch or jute with sand (in ratios of 0.25, 0.50, and 0.75) to improve the hydraulic properties (filter flux), removal ability, and cumulative capacity of the filter for a specific pollutant were evaluated. Initial tests were performed to evaluate the basic performance of the mulch and jute materials ("as received"). This performance was compared with the performance of the materials whose particle size was altered. This alteration of the size of particles within the filter material was done by separating the mulch materials into "coarse" and "fine" fractions Jute fiber was cut into significantly smaller pieces.

New policies and proposed regulations in New Jersey require that no increase in storm water pollutant loads from proposed residential and commercial developments occur. In order to achieve such a requirement, very advanced forms of storm water best management practices (BMPs) must be employed. Rather than using conventional detention basins, engineers must become much more creative with storm water management. A bioretention basin is one advanced BMP that can achieve very high levels of pollutant removal. It is designed to manage and treat storm water runoff using a conditioned planting soil bed and planting materials to filter runoff captured by a collection system and transmitted to the basin. The system combines physical filtering and adsorption with biological processes using a shallow ponding area, a surface organic layer, a planting soil bed, a sand filter, plant material, a gravel underdrain system (if sufficient permeability is not available for complete ground water recharge), and an overflow system. This paper will describe bioretention basin design considerations, expected pollutant removal efficiencies, and maintenance issues. A ten-year monitoring program that will demonstrate the pollutant removal efficiency of a newly installed bioretention basin discharging to a trout production, category one stream will also be discussed.

Indicators for assessing pathogen contamination and for distinguishing human origin and animal origin were investigated. Water samples were taken from storm sewer outfalls to a coastal lake during wet weather as well as from the lake during the dry weather. Counts of fecal coliform and fecal streptococci were used as microbiological indicators. Concentrations of fluoride, anionic surfactant, caffeine, fluorescence whitening agent, and ammonia were used as chemical indicators. The ratio of fecal coliform to fecal streptococci ranged from 0.2 to 3.0 indicating the contribution of both human and animal wastes. The presence of human waste at storm water outfall was confirmed by increased concentration of caffeine, fluorescence whitening agent, fluoride and anionic surfactant during wet weather in comparison to those in lake during dry weather. The presence of human waste was further confirmed by good correlation among all the chemical and microbiological indicators.

Highway traffic, maintenance, natural background sources, and deposition of air pollutants contribute to buildup of contaminants on highway surfaces. Consequently, during a rainfall-runoff event highways can produce an exorbitant per area loading of contaminants, which can subsequently degrade receiving water quality. The capacity of a wetland to mitigate pollutants in highway runoff, particularly metals, was investigated. Storm water runoff from a portion of a 30,000 average daily traffic highway was analyzed during 57 rainfall-runoff events. The runoff area consisted of two inner-most lanes of a four-lane highway composed of 1189 m² of asphalt pavement, draining to 279 m² of vegetated median, and then collected by median drain and discharged into a 557 m² wetland. In addition, a distributed input from 673 m² of pavement flowed across a vegetated highway embankment of 184 m² along the length of the wetland. In-situ data collection included rainfall volume and frequency, conduit flow rate, and temperature, conductivity, pH and dissolved oxygen in the runoff. During each rainfall-runoff event sequential samples were obtained and analyzed for metals, total suspended solids, and chemical oxygen demand from the point source inlet and wetland outlet. Flow-proportioned composite samples of sheetflow from the highway pavement edge were collected and analyzed along with rainfall samples. Sediment samples were obtained longitudinally from the wetland inlet to the outlet and analyzed for metal constituents.

As part of the U.S. Environmental Protection Agency's (EPA's) Environmental Technology Verification (ETV) Program, the Wet-Weather Flow (WWF) Technologies Pilot Program verifies the performance of commercial-ready technologies by generating quality-assured data using test protocols developed with broad-based stakeholder input. The availability of a credible and objective verification report will reduce, and in some cases eliminate, the need for on-site pilot or demonstration testing prior to selection of a given product. The use of technically sound test protocols and procedures ensures the value of the verification report to the equipment purchaser and permitter. NSF International is the verification partner organization working with the EPA's National Risk Management Research Laboratory to conduct the verification pilot. This paper describes the critical components for the ETV program for two specific technology categories: (1) flowmeters utilized for monitoring of combined sewer overflow (CSO) and stormwater discharges, and (2) Stormwater source-area treatment devices.

After 30 years, the Expo Park regional stormwater detention facility in Aurora, Colorado needed renewal to meet increased expectations for recreational and stormwater management uses, as well as to satisfy new requirements for water quality management and dam safety. Through intergovernmental cooperation and innovative engineering solutions, a 3-year, $4.5-million renovation is nearing completion that upgrades the facility to meet these multi-use objectives so that it can continue serving as a valuable community asset. This paper reports unique aspects of the improvements made to Expo Park. Improvements to the multi-use 60-acre park facility were made to provide water quality, improve site drainage, increase flood control detention, improve recreational usefulness and aesthetics, and upgrade the facility to meet jurisdictional State dam safety requirements. Although the facility is a regional storm drainage and flood control facility, it meets the criteria for a Class I Small dam by the State Engineer's Office (SEO) of Colorado. Dam safety related improvements included new outlet works, spillway improvements, and acceptance by the SEO for using irrigated turf grass as overtopping erosion protection for the emergency spillway. Construction began in late 1999 and will be completed in the spring of 2001. The project was funded by the City of Aurora and the Urban Drainage and Flood Control District of Colorado and was designed by CH2M HILL in Denver, Colorado.

The conversion of rural land to urban land, with an increase of impervious area, can be expected to increase the peak discharge, sediment loading, and other pollutants to the downstream environment. This paper described a methodology to use high resolution remote sensing information as input to the watershed model AGNPS 98 in order to enhance the watershed management and planning ability required in high development areas. The test case is Ashland, Missouri, where a creek is fed by stormwater from a watershed undergoing urbanization. The remote sensing inputs used were digital elevation models and land cover classifications derived from IKONOS data. Water-quality was simulated for both current conditions and two full development scenarios based upon continued development similar to existing conditions. A comparison of the water quality parameters indicated the relative sensitivity of particular subbasins to development pressures. Combining remote sensing images and AGNPS 98 modeling capabilities provides planners and engineers with a tool to evaluate alternative strategies prior to making management decisions.

The Thunder Bay Hydroelectric Project is located in the northern part of Michigan's Lower Peninsula. The project structures are within the Thunder Bay River watershed. The Thunder Bay River discharges into Lake Huron at Alpena, Michigan. In December 1998 The Federal Energy Regulatory Commission issued a new license for the project. The new license had two major requirements for water quality monitoring. The first requirement was for checking dissolved oxygen and water temperature at several locations upstream and downstream of the dams as well as in the reservoirs. This paper presents the results of the first year monitoring dissolved oxygen and temperature. The second requirement is testing water samples for contaminants. This program will begin in 2001.

Five hundred and fifty-seven sites have been monitored in the Lake Okeechobee watershed, Florida, for compliance under a regulatory program since 1989. Of those sites, 154 were actively monitored for phosphorus concentrations during the period from October 1998 to September 1999. Seventy-seven of the 154 sites were considered to be out of compliance. An out of compliance site is defined as a site having runoff with phosphorus concentration exceeding the permitted discharge limit. The discharge limits were established by the "Works of the District - Lake Okeechobee Basin" Rule (Chapter 40E-61, Florida Administrative Code). Based on measured concentration values and simulated runoff using an agricultural non-point source pollution model, CREAMS-WT, the 77 out of compliance sites produced an estimated 46 metric tons (t) of phosphorus load, of which an estimated 22 t of phosphorus reached Lake Okeechobee on an average annual basis. The remaining estimated 24 t of phosphorus load was retained/assimilated by streams and wetlands in the discharge transport system between the sites and the lake. Of the 77 out of compliance sites, 12 sites had a phosphorus loading rate equal to or greater than 3.0 kg/ha and were placed on the priority list for the Critical Restoration Project in the Lake Okeechobee watershed. To estimate the possible phosphorus load reductions from these 77 sites, two hypothetical scenarios were modeled. The first scenario reduced phosphorus concentrations in runoff to the permitted discharge limit. The second scenario changed current land uses to native rangeland with an estimated annual off-site total phosphorus areal loading rate of 0.114 kg/ha. Model results showed that the first scenario reduced the phosphorus load to the lake by an estimated 15 t. The second scenario reduced the phosphorus load by an estimated 21 t.

Tampa Bay Water, Florida's largest wholesale water supplier, has pioneered development, application and implementation of a unique integrated surface-ground water simulation model in concert with an optimization program (S-O) to operate multi-wellfield water supply facilities in west-central Florida. These wellfields are operated as an integrated system using this set of simulation-optimization models giving priority to minimization of environmental impact while reliably meeting demands. This management program called the Optimized Regional Operations Plan (OROP) has been in effect since January 1999 and is used to produce a prioritized production schedule for 172 wells in 11 inter-connected facilities on a bi-weekly basis. The OROP database is updated as data become available from various sources including the agency's environmental and hydrological monitoring programs, the national weather service rainfall stations, and water production information; some of which are automatically relayed through a SCADA system.

The present study is conducted to assess the fate of the dredged material placed on the channel margins of the lower Apalachicola River by using the 3-dimensional numerical model, CH3D-SED. The fate of the dredged material is needed so that a comprehensive analysis could be performed to develop quantitative estimates of the effects of sediment deposition on native aquatic biota and their habitat. The CH3D-SED model provides information on sediment movement, channel bottom erosion/deposition depth, and river water depth in the lower Apalachicola River for the currently used dredging and placement techniques. This CH3D-SED model has the ability to mark sediments in different locations of the channel and track these sediments as they are eroded, deposited, mixed in the channel bed material and later re-suspended during the transport processes. With the benefit of this sediment tracking ability a comparative evaluation is conducted for different dredge material placement options.

As water/environmental resource managers, we repeatedly hear about the value of involving stakeholders in resource management and planning. The law requires public involvement in many processes, and many argue that it can actually have political benefits for the project. So, we bite the bullet and bring different parties together to get feedback on plans and options. Progressively, some stakeholder forums are being created that are central components to the needed planning and management analysis. It can greatly benefit the sponsoring entity, to better understand the stakeholder group perspectives and to operationalize that insight for a more effective and efficient participatory planning process. This paper describes the elements of successful stakeholder management and highlights recent experiences in Florida water and environmental planning activities.

A challenge for policy makers is to formulate a withdrawal permitting strategy with a sound scientific basis that maintains ecosystem ecological integrity and resource sustainability. The proposed annualized flow duration curve (AFDC) framework can provide such a basis. The framework allows for aggregate current condition evaluation, critical ecological streamflow controls integration, firm yield determination, and withdrawal impact assessment. The fundamental premise of the AFDC approach is that maintenance of a stream's ecological integrity depends upon maintaining an appropriate flow regime (magnitude and frequency). The AFDC provides a graphical tool to illustrate the quantity and frequency of streamflow available in a river basin. The AFDC, as compared to the traditional period of record flow duration curve (FDC), has a robust statistical interpretation of streamflow that allows for the determination of high and low flow AFDCs with a specified recurrence interval T (T-year return period). Ecological data can be used to identify critical points on the AFDC that serve to guide the timing and magnitude of withdrawals such that critical flow levels are maintained. These points provide the basis necessary to determine maximum available withdrawal rates. An estimate of the available annual yield is determined from a quantitative analysis of this modified flow regime. The AFDC framework also facilitates the simulation of the modified streamflow regime based on historic time series data. This study illustrates the application of the AFDC methodology to minimum flows and levels establishment in the lower Suwannee River basin in Florida. The case study characterizes the median (2-year) AFDC and the family of AFDCs corresponding to a series of annual high and low flow return periods under existing conditions. Control points that correspond to the high, medium, and low flow regimes are used to demonstrate the establishment of the modified flow that meets these ecosystem requirements. The new streamflow regime is examined by inverting the AFDC.

The single most important issue for Georgia in the 21^st Century is how to manage its surface and ground water resources. The question is how shall water be managed to satisfy the need for adequate supplies of clean water by the different, often competing, users. Georgia's water problems can be solved with partnerships of government leaders, business leaders, professionals and the citizens of Georgia. However, Georgia must develop sound water policy based on a combination of water science, water engineering, water technology, water law and water economics.

The process of evapotranspiration (ET) is involved in physical environmental parameters as well as the vegetation parameters. The opening of stomata in a single leaf and the group effects of stomatal opening under vegetation canopy are usually the main indicators of the viability of transpiration process and considered in some ET estimation equations. Comparing with the huge collected field data of stomatal resistance and other vegetation parameters for crops, those for wetland vegetation are not enough to show the characteristics of various wetland vegetations in different geographical locations and thus, need to be further developed. An automatically data-recording lysimeter system with three lysimeters and one weather station was installed in Ft. Drum marsh, upper St. John's river basin, Florida. The plants inside three lysimeters were cattail (Typha domingensis), sawgrass (Cladium jamaicense), and open water, respectively. In addition to the weather and lysimeter data collection from this lysimeter system, seven field trips from Oct 1996 to Apr 1998 in each season were made to measure the vegetation parameters related to ET estimation such as stomatal resistance, leaf area index (LAI), canopy height, plant density, biomass, canopy temperature, and air temperature. The average stomatal resistance for cattail is 3.35 sec cm–1 with a standard deviation of 0.86, while that for sawgrass is 3.60 sec cm–1 with a standard deviation of 0.98. Furthermore, in the seventh field trip, the LAI and stomatal resistance were measured along the plant vertical positions, and were found linearly related to plant height. Therefore, a different approach of estimating canopy resistance was proposed.

A fundamental marsh evapotranspiration has been on going in Ft. Drum marsh, upper St. John's river basin, Florida, where an automatically data-recording lysimeter system with three lysimeters and one weather station was installed. In order to expand the results of the fundamental lysimeter study into the other parts of the marsh, remote sensing tools should be introduced. However, vegetation species in similar geomorphological or geographical locations tend to be more alike and difficult to identify without taking a very close view. Thus, a scaling-up approach with multi-scale remote sensing techniques was adopted. Remote sensing techniques of three different scales from ground, sky and space were utilized in this study. Foremost, a spectral radiometer was employed to measure spectral reflectance of sawgrass and cattail as well as other vegetation parameters related to ET estimation seasonally nearly for two years. The results displayed distinguishable differences between two vegetation types in some wavebands. Then, a flight for aerial hyperspectral imaging was performed on May 12, 2000 with the ground truth work. The mounted hyperspectral imager has 64 wavebands from 395 nm to 905 nm. The ground truth work included identification of vegetation species, spectral measurements by the spectral radiometer, multispectral image acquirements by a narrow-waveband multispectral imager, measurements of leaf area indices (LAI), and water quality sampling. The results of hyperspectral imaging showed clear wetland vegetation delineation. Finally, a LandSat 7 TM image on the day before the aerial hyperspectral imaging day was obtained to collaborate the results from hyperspectral images to estimate the marsh ET values.

The restoration of the Everglades is arguably the most important environmental endeavor to be undertaken within the United States. Decades of development, drainage, and water supply uses have lowered water levels within the Everglades National Park (ENP) to historically low levels. These low levels have resulted in the oxidation and subsidence of natural soils, the reduction in wetland extent and diversity, and a reduction in the environmental integrity of the overall system. Restoration of the Everglades, as one may imagine, is not a simple process. The goal of increasing water levels in the ENP to approach natural levels cannot be accomplished without accommodating the needs of the surrounding area. One such area of restoration is the 8.5 Square Mile Area. This area, actually covering about 10 square miles, is bounded on the east by the L-31N canal and on the south, west and north by the Everglades Expansion Area. This area, comprised primarily of residential, agricultural, and vacant land, was found an important area in the overall restoration process. Congressional mandates accompanying the Everglades Restoration Act dictated that elevation changes in the park must be accompanied by flood mitigation in the 8.5 SMA. The ENP, desiring to maximize wetland extent and function and establish water levels similar to that, which historically occurred in North Shark River Slough, supported the buy-out of the 8.5 SMA area. Residents of the area, desiring to maintain their unique lifestyle supported the building of a flood control levee and seepage canal around the area.

Frequency analysis of short duration rainfall and resulting isohyetal maps for various return periods are needed for many designs, regulations and hydrologic applications. The South Florida Water Management District manages water resources on approximately 46,600 square kilometers (18,000 square miles) of land area. The District collects rainfall data from several hundred gages, which are located within its 16-county water management area. Daily rainfall data collected between January 1, 1900, to December 31, 1999, a period of 100 years, were used for this study. A total of 1,071 gage records with varied period-of-record is available. A total of 973 gage records was used to determine the maximum rainfall values. An analysis of the maximum rainfall data was performed for one-day, three-day and five-day durations. In addition, an analysis of a total of 61 rainfall events that occurred due to hurricanes or tropical storms in the last 100 years was performed. A set of stations having daily rainfall time series with more than 50 years of gage records was selected for frequency analysis of maximum daily rainfall. For these stations, the annual or partial duration series were constructed. A total of 86, 66 and 65 stations was selected for one-day, three-day and five-day durations, respectively. Seven standard probability distributions were applied to the data series of each selected station. Based on a pre-established, best-fit criterion, a probability distribution was chosen to fit the data series of the each station. The results provided the rainfall estimates for various return periods at each station. This process was applied to all three durations. Several maps showing isohyetal contours for six return periods and three durations were prepared using Kriging interpolation.

The Regulatory Division, Jacksonville District, U.S. Army Corps of Engineers (Corps) used Geographic Information System (GIS) software and data in a project to improve reviews of permit applications. The Corps assembled citizens, landowners, non-governmental organizations, agencies, and other stakeholders to participate in the discussion of concerns. The project encompassed a very large geographic area and explored a wide variety of issues. The use of GIS was different for each step in the process. In the initial steps of scoping the project and familiarizing the participants with the study area, GIS was used to display data. The identification of the data that would be useful to the participants and the determination of the number of maps to display influences the efficiency of the group. After the group listed issues and defined evaluation factors, GIS software was used to analyze and report the results of applying the evaluation factors to several predictions of what permit applications will be received. Finally, GIS was used to distribute the information, primarily through a set of draft maps identifying locations where a Permit decision may particularly influence a natural resource issue. Concurrent with this project is a larger on-going effort that allows a reviewer to enter the location of a newly received application and receive a text report. This demonstrates how the use of GIS needs to be tailored to the different stages of the participatory process.

This paper describes the hydrologic conditions of the channelized Kissimmee River and its associated floodplain for three years prior to the first phase of restoration, which began in June 1999. Discharge, stage, and velocity data, collected in remnant river channels and within the floodplain, are characteristic of the flood control features and management of the current system. Discharges through remaining river channels were zero during 70% of the baseline period. Water depths on the floodplain were typically less than 7.6 cm (0.25 ft). Implementation of the Kissimmee River Restoration Project is expected to reestablish hydrologic regimes with natural seasonal patterns and variability similar to the historic system. A comprehensive restoration evaluation program will assess changes and thereby measure the success of the KRRP by comparing pre- and post-restoration data to specific restoration expectations.

The Immokalee Area Study (IAS) is an on-going study of approximately 78,900 ha. (195, 000 acres) of eastern Collier County in southwest Florida. The major landowners within the study area initially proposed the 3-year study in response to increasing concerns over regional issues such as long term growth, natural resources, economic sustainability and potential zoning and comprehensive plan changes. The primary goal of the study is to create a comprehensive strategic long-range plan for the area based on accurate data, broad based public input, and recognition of the important contributions and constraints of agriculture in the local and regional economy. Funded by the major landowners in the study area, the IAS is occurring in four stages: data collection and analysis of existing conditions; land use research and optional scenarios; impact analysis of land use options, and amendments to the Collier County Growth Management Plan. A special committee, appointed by the Board of County Commissioners, and comprised of local residents, business owners and environmental interests, conducts period public meetings to allow for study oversight and to provide a mechanism for public input and discussion. Technical review of the study's main issues is being provided by various state and federal agencies.

This paper describes new and improved flow computation procedures at prototype gated spillways located on the Kissimmee River in Central Florida. Flow computations are needed in support of a major restoration project in the Kissimmee River basin. These calculations are used to conduct water mass balance studies, develop sound water quality sampling procedures, and evaluate the overall response of the river-floodplain ecosystem to restoration efforts. The present work focuses on improved flow calculation procedures for submerged orifice flow conditions at Structures S65A, S65B, S65C, S65D, S65E, and S65, in the lower basin of the Kissimmee River. Traditionally, flow equations developed from small-scale laboratory testing are used to compute flow at these structures. The drawback of this approach is the significant errors, sometimes in excess of 30%, that result in the estimates of the flow rate. Traditional flow computation procedures at gated spillways are first presented. These procedures are compared with the newly developed flow equations and field flow measurements. Particular attention is on the errors between field flow measurements and computed discharges. The new equations resulted in average relative errors that are less than 7% for all Kissimmee-River gated structures.

The St. Lucie Estuary receives freshwater input from two tributaries (North and South Forks of the St. Lucie River) and three major drainage canals (C23, C24 and C44). The St. Lucie Estuary has many characteristics that typically result from eutrophication. Seagrasses and oysters, once abundant in the estuary, are virtually absent today. The St. Lucie Estuary is now a phytoplankton based system with high chlorophyll a concentrations, high nutrient concentrations, and hypoxic and anoxic events in bottom waters. The South Florida Water Management District has been monitoring nutrient concentrations at canal discharge structures since the late 1970s. Nutrient levels in the Estuary have been monitored by the district since 1990. These field data were combined into a 10-year concurrent data set to investigate the influence of drainage canal discharge on the water quality conditions in the Estuary.

With the implementation of a new funding source (e.g., user fee or special assessment) for stormwater management programs, a municipality imposes a new financial burden on the public; that is, individual customers have to pay a new monthly fee or annual assessment for stormwater services. Furthermore, elected officials have to vote to impose the new fee or assessment on customers, a difficult decision to make. As a result, the key to a successful stormwater utility implementation is public approval. The subject of this article is to present methods for public education and approval. While individual methods for public acceptance will be discussed, the overall theme of this article and the experience of cities and counties with adopted utilities is that the public must want the stormwater service to be provided by the new revenues before they will agree to pay for the service. The focus of the community acceptance process is therefore not the stormwater fees or assessments but rather the stormwater service the new revenue will provide. Of course, elected officials and the public at large must believe that the rate structure is fair and equitable; however, education in these areas alone will not be sufficient to obtain community acceptance. The public and their elected representatives must be convinced that the stormwater services provided by the new revenues are essential and needed to improve their quality of life, health or safety.

Given the complex nature of hydrologic process in South Florida and the flood protection works that affect the hydrologic cycle, it is essential to have hydroinformatic systems to assist decision makers. The hydroinformatic systems must contain hydrologic models that can accurately simulate physical processes at the proper time and space scales without the crude schematization that has been common in previous modeling systems. The developed hydroinformatic system includes the FEMWATER123 model supported in the Department of Defense Groundwater Modeling System (GMS). The developed model (FEMWATER123) uses the Galerkin finite element method to simulate 1-D canal flow, 2-D overland flow, and 3-D groundwater flow in a coupled manner. The canals are simulated using the 1-D diffusive wave assumption including hydraulic structures with individual operation rules that are updated at one-minute intervals. The overland areas are simulated using the 2-D diffusive wave assumption while variably saturated groundwater flows are calculated using Richards equation. Results from the South Florida application are presented.

Artificial Neural Networks (ANN) is a computational approach emulating the ability of the biological neural network by interconnecting many artificial neurons. ANN can identify and learn correlated patterns between input data sets and corresponding target values. It can also process problems involving highly nonlinear and complex data even if the data are imprecise and noisy. ANN method is ideally suited for the prediction of chaotic time series such as water resources data, which are known to be very complex and often nonlinear. One of the most popular neural networks is the layered feed-forward neural network with a back-propagation (BP) least-mean-square learning algorithm. In the paper, we present an application of neural network method to forecast the real-time flow change in the Apalachicola River. The Apalachicola River is the lower segment of the Apalachicola-Chattahoochee-Flint basin and is formed by the joining of the Flint and Chattahoochee rivers at the Florida border, which is lies in the southeastern United States with a length of 105 miles and a drainage of 17,200 square miles. Forecasting of river flow, with a warning time of a few hours or days, would benefit water resource management activities in the river basin. In this study, we apply neural network methods to forecast of flow in real time sense based on the historic and current observation of flow at Sumatra station on this river. The network is firstly trained, and then used to forecast flows with lead times varying from 1 day to 5 days. The performance of the neural network model is validated by comparison with observation data. Preliminary results have shown that neural networks can be used to reasonably forecast Apalachicola River flow.

The Tampa Bay Regional Reservoir is one component of Tampa Bay Water's Master Water Plan. The Tampa Bay Regional Reservoir is a proposed off-stream reservoir that will be used to store excess surface water pumped from the Alafia River and Tampa Bypass Canal pump stations for use as a potable water supply. The reservoir will be an above ground, earthen structure encompassing about 1,100 acres with a storage volume of approximately 15 billion gallons. It is important to estimate the magnitude of this seepage in order to evaluate any potential impact to the reservoir embankment, impact on the yield, and potential impacts on the environment. The seepage evaluation utilized data generated during a detailed geotechnical site characterization, and data generated during site specific aquifer performance tests (APTs). The finite element computer program SEEP/W (Geo-Slope version 4.2.2) was chosen to simulate flow from the reservoir. SEEP/W allowed hydrogeologist and geotechnical engineers to combine the engineering components of the completed reservoir (embankment, toe drain, cut-off wall) with the site-specific hydrogeologic units for a "complete" simulation. The model calculated, based on a full reservoir and representative site conditions, a water loss from the reservoir of 4 million gallons per day (mgd). Assuming model uncertainties of approximately 40%, a range of total seepage of approximately 2 to 6 mgd can be assumed.

The Everglades Wetland Water Quality Model (WWQM) was developed based on mass transport and kinetic equations of nutrients in water, sediment, and emergent wetland plants. The model consists of four submodels: eutrophication, chemical equilibrium, sediment, and emergent vegetation. The model is based on the integrated compartment method (i.e., the mass transport equation is applied in integrated form to control volumes). The three-dimensional nature of the water quality model includes consideration of a floating algal mat, a water column layer, a benthic periphyton mat, and a detrital litter layer. The four submodels are briefly described. This model has been used to predict water quality and phosphorus removal efficiency undervarious nutrient loads, flow conditions, and dominant vegetation types. It has been calibrated with monitoring data from the Everglades Nutrient Removal (ENR) Project prototype stormwater treatment area (STA) and with observed and experimental data from the Water Conservation Areas. The WWQM provides a tool for understanding and optimizing the nutrient removal processes in treatment wetlands.

The need for public water supply in west central Florida has reached a critical juncture. Groundwater, long the primary source of potable water is a source is finite. Though the Floridan aquifer is arguably one of the most productive groundwater aquifers, this production has impacts. Regulatory agencies have mandated that groundwater pumpage be reduced over the next ten years to reduce the historic impacts of pumpage. Tampa Bay Water, the regional water supply utility for the tri-county area comprised of Hillsborough, Pinellas and Pasco Counties, is actively pursuing additional alternative water supplies including desalination and reverse osmosis. Even with the potential for these new supplies, maintaining the ability to continue to withdrawal groundwater supplies is essential. The essential question remains: How can you mitigate for the impacts of groundwater withdrawal while maintaining sufficient supplies? The answer is rehydration — a method for Sustaining a Critical Water Resource.

The restoration of river systems is a critical need within the State of Florida. Development pressures have robbed the environment of many of its most precious riverine systems, replacing them with urbanized systems of seawalls, docks and other facilities to make river access easier. The upper reaches of the Withlacoochee River have experienced many of the changes that have impacted other rivers. Downstream development has changed the flow patterns in the river. Locals speak of a time when water levels in the upper reaches remained at flood stage for a significant portion of the year. Maintenance of water levels in the upper reaches of the river will serve to improve the biological function of the river and increase the potential for aquifer recharge in the region of Lake Panosoffkee and Lake Tsala Apopka.

From a water resources perspective, Atlanta's geographic location is problematic. The city is located in the Piedmont Province, a region with limited ground water and situated near the headwaters of the streams that the region depends on for water. In addition, a continental divide runs through Atlanta, resulting in small stream forming in and flowing from the metropolitan area. With increasing demands for water due to population and economic growth, it is essential that Atlanta make the most effective use of the water it has. In addition, the problems confronting the Atlanta region may be a harbinger of similar problems that will appear as other metropolitan areas in the Piedmont Province grow.

A water quality monitoring program for the water runoff at three unconfined dredged material disposal sites in Glynn County, Georgia, was conducted during hydraulic dredging disposal operations for the Atlantic Intracoastal Waterway (AIWW) maintenance dredging. The monitoring was performed on the water runoff into the adjacent water body at a total of eleven locations from the three disposal areas along the AIWW. The dredged material was a fine grained clayey silt and silty clay. Field measurements included water temperature, dissolved oxygen (DO), pH, conductivity, salinity, and turbidity along with a brief description of weather, water, and tide conditions. Water samples were collected from one location and tested in the laboratory for total suspended solids (TSS). TSS concentrations for the remaining locations were estimated through a correlation established by statistical regression analysis between field turbidity measurements and TSS laboratory analytical results. As expected, field measurements and laboratory analytical results indicated that the turbidity and TSS levels were increased during the disposal operation, but not significantly. Water temperatures at the measurement locations did not appear to be affected by the disposal operation. The DO levels also did not appear to be significantly affected by the disposal operation, but did appear more to be affected by weather and water conditions. The pH, on the other hand, appears to be affected by the disposal operation. Salinity and conductivity at the three areas appeared to be co-related but not affected by the disposal operation. Based on the results, it appears that water quality of runoff can be acceptably controlled at unconfined disposal sites.

Accumulating stormwater runoff from developed property must be managed in an organized and systematic manner if property owners are to enjoy the full use of their property. The burden of managing the collection, conveyance and treatment of this accumulating stormwater typically falls to the community. Stormwater facilities must be constructed and maintained to reduce the negative impacts of runoff. These systems and their maintenance are expensive. As the real costs of expanded stormwater management programs have become apparent, more and more communities across the country have turned to user-charges - and their delivery vehicles, stormwater utilities - as the primary funding source for expanded maintenance and new infrastructure. If the stormwater management program constitutes the "bones and muscle" of a stormwater utility, the rate methodology forms the heart. Sound rate methodology draws upon key concepts from public finance, utility theory, economics, law and engineering science to develop a rational, carefully structured, broadly encompassing rate theory for stormwater user-charges around which defensible rate structures of many forms may be crafted. A solid approach allows clear answers to such questions as "What exactly does this utility sell?", "I live on top of a hill, why should I pay?", "My runoff does not enter a City/County/District system, why should I pay?", and "I have my own on-site facilities, don't I at least get a reduction in my bill?"

Water from the Roanoke River began to flow in 1998 through a 76-mile interbasin pipeline into the reservoir system serving the coastal City of Virginia Beach and other residents of southeastern Virginia. The opening of the pipeline was preceded by more than 15 years of controversy, including several failed attempts at negotiation, a wide range of highly contested administrative decisions, and a variety of lawsuits. Efforts to expand the area's water supply accelerated in the late 1970s and early 1980s due to severe drought that resulted in imposition of water-use restrictions. The primary source of increased demand was population growth in Virginia Beach. The projected demands enjoyed substantial credibility because they had been developed in a U.S. Army Corps of Engineers' study. The proposed source of water was a hydropower impoundment on the Roanoke River, which has origins in Virginia and North Carolina but flows entirely in North Carolina below Lake Gaston. The proposal generated opposition from Virginia localities in the area of the Lake and from North Carolina. A bi-state committee was formed in the early 1980s by the governors of Virginia and North Carolina to explore mutually agreeable solutions to the water supply issue, but negotiations ultimately were unsuccessful, as were renewed efforts at negotiation as the pipeline was nearing completion. Federal decision processes ultimately determined the fate of the proposal. Administrative decisions under such measures as the Clean Water Act section 404 permit process and the consistency determination of the Coastal Zone Management Act were usually followed by judicial proceedings to resolve challenges. These processes consistently found that the transfer would have no significant environment impact, and the project was ultimately approved. This paper uses the Lake Gaston experience as a case study to provide insight into the process of resolving conflict over sharing of transboundary waters, including the factors essential to success of negotiated conflict resolution.

Atlanta straddles the headwaters of four different basins, all of which drain out of Georgia into other states. As the city operates an integrated city-wide water system, virtually everything done in managing the cities water system implications interbasin and interstate water transfers. The robust growth in the Atlanta area had led to large withdrawals, with projections for even larger withdrawals in the near future. In 1991, Alabama and Florida brought suit to enjoin the U.S. Corps of Engineers from developing a reservoir in fulfillment of Atlanta's plans. Alabama also saw other plans for new reservoirs in western Georgia as threatening Alabama's development plans. Florida was anxious to assure that sufficient water flowed into Apalachicola Bay to nourish oysters and other marine life. Eventually, the parties agreed to hold back on the litigation while studying and negotiating a solution. The growing controversy among Alabama, Florida, and Georgia over the Chattahoochee/Apalachicola River Basin and also over the Alabama-Coosa-Tallapoosa River Basin then led to two agreements among those states and the federal government sometimes referred to collectively as the Southeastern Water Compact. These agreements essentially froze present uses on both river systems in place while the three states and the Corps of Engineers undertook to study how to resolve the controversy. The three states agreed to fund an elaborate joint study while holding the legal action in abeyance. The three states have not yet been able to reach any final agreements.

A comprehensive plan to restore the greater Everglades ecosystem was approved by Congress in the Water Resources Development Act of 2000. The plan, which involves extensive modifications to the existing water management system in south Florida, enjoys widespread support from a broad range of interests. Public outreach and stakeholder involvement were integral parts of the development and acceptance of the Comprehensive Plan. In March 1994, Governor Lawton Chiles established the Governor's Commission for a Sustainable South Florida to recommend strategies for ensuring the long-term compatibility of a strong south Florida economy and a healthy south Florida ecosystem. In an effort to ensure coordination of Everglades restoration efforts at the federal level, U.S. Interior Secretary Bruce Babbitt created the South Florida Ecosystem Restoration Task Force in 1993. Both the Governor's Commission and the Task Force played key roles in the development of the Comprehensive Plan and its acceptance by stakeholders and the public. This paper discusses the process used to involve stakeholders in developing the Everglades restoration plan. The paper focuses on the role of the Governor' Commission and the Task Force in developing the restoration plan and describes how they were used to develop consensus on the Comprehensive Plan.

The Florida Keys have long been recognized at local, state and national levels as ecologically rich, culturally significant and environmentally sensitive. The Florida Keys are designated as an Area of State Critical Concern by the State of Florida. This designation requires that Monroe County, which includes the Florida Keys, meet more stringent planning standards. The goal of the Florida Keys Carrying Capacity Study (FKCCS) is to determine the ability of the Florida Keys ecosystem to withstand all impacts of additional land development activities. Due to the innovative and controversial concept of the FKCCS, it was recognized early in the Study process that public involvement will be critical to the acceptance of the Study results and products by stakeholders. Without aggressive public outreach efforts, the Study results and products would most likely be shelved and not used by the local governments as intended, resulting in a large waste of time and taxpayer dollars. Therefore, public input has been solicited from the beginning of the Study, during development of the conceptual Scope of Work and continues to be sought from local citizens. The Community Character and Quality of Life data, which is a part of the social environment category of the FKCCS, will be exclusively derived from input provided by local citizens. An aggressive public outreach program has been implemented to ensure public input into the Study is acknowledged and incorporated whenever possible.

In 1997, the Florida legislature passed legislation which gave the Department of Environmental Protection (DEP) the lead role in "developing and implementing comprehensive ecosystem management solutions, in cooperation with both public and private regulated entities, which improves the integration between land use planning and regulation, and which achieves positive environmental results in an efficient and cost- effective manner". The DEP is using the "Team Permitting Process" as one tool to effect the legislative mandate. The "Team Permitting Process" comprises eight stages: (1) pre- application planning; (2) pre-application meetings and site visits to identify and discuss issues; (3) consolidated application submittal; (4) consolidated application review and request for additional information; (5) consolidated response to the request for additional information; (6) consolidated evaluation of the project; (7) individual or joint final agency action; and (8) individual or joint compliance and enforcement actions. The discussions and conclusions presented in this paper are drawn from four multi-million dollar phosphate mining and processing projects encompassing over 60,000 acres of land in Central Florida. This paper analyzes how the "Team Permitting Process" is being used to improve the linkage between land use planning and regulation by bringing together the broad spectrum of interests represented by the federal, state, and local governments, the general public, affected individuals, and the applicant. The failures and successes of the "Team Permitting Process" are discussed and recommendations are made to improve the effectiveness and efficiency of the process.

Hillsborough County of Florida is currently working on stormwater management master plan for all its 17 watersheds. The purposes of master plan are to identify all flooding problem areas, and find out the alternatives. The major tool of the stormwater management master plan is the Environmental Protection Agency (EPA) Storm Water Management Model (SWMM). Hillsborough County modified this model based on county's situation. In this modified version, the Soil Conservation Service (SCS) Curve Number method (SCS-CN) was used to determine the rainfall-runoff process.

Reflectance characteristics obtained from Landsat TM imagery were used to assess the condition of cypress (Taxodium sp.) wetlands in West-central Florida. The health classifications, or quality rankings, were based on the qualitative assessment by the Southwest Florida water Management District of 184 cypress wetlands in a karst region north of Tampa Bay. Landsat images from 1992 and 1994 were used in combination with vector GIS Land cover data to identify some 6000 cypress wetlands in 2000 square km region. Differences in the mid-infrared bands were observed among the reflectance signatures of the 184 wetlands of different quality rankings, which allowed the classification of all 6000 wetlands as severely stressed, moderately stressed or good condition. Classifications were preformed using GIS databases from two different sources, and the results were compared.

This paper presents a validation test of a three dimensional numerical model, CCHE3D, using a large amount of 3D field data measured in the Mississippi River and its application to studying channel navigation problems. The 3D velocity data set was collected in Victoria Bendway, a curved channel reach, using an ADCP imstrumentation. The simulated flow Field and the measured data showed good agreement, thus the model's applicability to simulate natural river processes was confirmed. Because of the channel navigation problems in Victoria Bendway, several submerged weirs were constructed for improving navigation condition. The validated CCHE3D model was then applied to study the channel flow and investigate the effectiveness of these submerged weirs by comparing the simulated primary and secondary flow patterns with and without these weirs. It was found the submerged weirs improve the navigation conditions by reducing the strength of the helical secondary flow.

The Federal Highway Administration's Hydraulics Research Laboratory has facilities to physically and numerically model hydraulic and sediment transport phenomena to support State highway administration initiatives. Recent advances in physical modeling instrumentation have facilitated flow visualization to support research. Flow visualization is now performed using the hydrogen bubble technique whereby a platinum wire is mounted vertically upstream of a bridge structure (pier, abutment, etc.) in the test flume. A graphite rod is used as an anode. The hydrogen bubbles produced are small enough (O/ < 0.025 mm) that their buoyancy may be ignored within the visualized area. By employing pulsed time line markers with a specially built hydrogen bubble generator, it is possible to visualize the phase speed of the diving current formed at the face of the structure. This diving current is usually responsible for bridge scour.

Future computational codes will be capable of simulating the movement of a single fish through moving fluid. Present codes can simulate (1) turbulent flow around stationary objects (hydraulic models); (2) flow around a moving foil attached to a wing in unidirectional flow; (3) the changes in pressure and turbulent kinetic energy on a "virtual fish" along a Lagrangian pathline through a hydroturbine; and (4) the neuro-skeletal-muscular basis for fish tail movement independent from fluid inertia. No existing model can combine two or more of the above features. The problem is complex: to analyze the fluid dynamics of three-dimensional flow around an object that continuously changes shape and the angle of attack, and is positively influenced by the thrust generated by reverse Karman sheets in the wake region. These computations must be dynamically tied to the neuro-skeletal-muscular response of the simulated fish to the fluid surrounding it. Requirements of the future modeling effort include (1) solving the Navier-Stokes equations in a highly unsteady 3-D flow field; (2) changing internal boundary conditions at each time step to accommodate the change in position, orientation, and velocity of the simulated fish; and (3) eventually linking the fluid dynamics to the neuro-skeletal-muscular system of the fish. A suggested stepwise research approach is described to move towards accomplishing this formidable task.

A sediment yield model based on the linear transformation of rainfall to runoff was developed to estimate the sediment yield from small catchments. The model makes use of the antecedent precipitation index (API) of the catchment and a variable gain factor in order to appreciate the effect of the catchment wetness. Thus being a variable gain factor model (VGFM) it can be related to a special form of the Volterra-type non-linear model. The results obtained on the basis of model efficiency and comparison of mobilized sediment to the observed values indicate the suitability of systems type models for estimating sediment yield from small catchments.

Floodplain management and design of hydraulic structures, such as bridges and culverts, require flood frequency estimates for various return periods at ungaged watersheds. These estimates are usually made with regional regression equations or rainfall-runoff models. The regional regression equations are developed by relating flood discharges, such as the 100-year flood discharge, to watershed and climatic characteristics at gaging stations. For application at an ungaged site, one must determine the applicable watershed and climatic characteristics. Rainfall-runoff models are often based on a design storm where rainfall amounts are taken from applicable rainfall atlases and a time distribution is assumed. These two different approaches can provide widely differing estimates of the design discharge. Often flood discharges are available from both regression equations and rainfall-runoff models prior to developing the floodplain boundaries or designing the hydraulic structure. This paper describes an approach for comparing estimates from regression equations and rainfall-rainfall models to gaging station data and determining the most reasonable flood frequency estimate.

This paper presents the measurement of boundary shear stress around the base of some elliptical shaped bridge piers using Preston tube technique. The uniform flow was established and a series of measurements having different discharges and channel bed slopes were undertaken. General results are established and then the effects of flow separation on the hydraulic theory are assessed. The Analysis of results shows that behind the bridge piers (horseshoe area), the amount of boundary shear stress reduces dramatically. The figure for the rate of boundary shear stress of nose to end is about τ_r=τ_n/τ_e=3.6. It has a remarkable reduction even in steep slopes. The bed shear stress was found to intensify near the nose of the piers. The distribution of boundary shear stress in both mild and steep channel bed slopes along span wise direction is presented that may give a valuable perspective of the flow action around piers.

Experimental studies were conducted in a clear water condition to investigate the functioning of a sack gabion as a scour countermeasure at bridge piers. For different sizes of fill materials of sack gabions no difference was observed in the initial movement of sack gabions. Significant factors on the dislodging of sack gabions are approaching flow depth and velocity, pier width, and thickness and length of sack gabions. It was observed that the stability of the sack gabions is increased in a collective body of riprap stones than the placement of individual riprap stone. The length of a sack gabion has significant effect on its initial movement and the stability of a sack gabion was found to be increased by lengthening the length of gabions. The experimental results were used to derive formulas sizing gabions for scour protection at bridge piers.

The Northern Gulf of Mexico is an important area of interest from many perspectives, such as commercial, military and recreational. It is widely recognized as one of the top shell-fish producing and recreational regions in the United States and is a region where frequent military training exercises take place. To assist local, state and federal agencies plan for resource management and military training, a regional scale modeling system is being developed for these waters, that is, for the Mississippi Bight/Sound and adjoining Mobile Bay, Biloxi Bay, Bay St. Louis, and Lake Borgne. The modeling system, consisting of a three-dimensional circulation model, a cohesive and non-cohesive sediment transport model, a wave model, and a transport model will provide a reliable means to forecast littoral circulation, sediment suspension and transport, surface waves and conservative and non-conservative water quality constituents. The modeling framework adopts a high-resolution orthogonal curvilinear grid, which accurately resolves bathymetric and coastline features of the region, especially in the vicinity of the barrier islands. The southern model boundary follows the continental shelf break, roughly the 100m isobath, a natural dynamical barrier between the Sound and the rest of the Gulf of Mexico. This modeling system forms the highest horizontal resolution part of a triply nested series of three dimensional circulation models ranging from the North Atlantic Ocean to the Gulf of Mexico to the Mississippi Bight/Sound. Novel open boundary conditions are employed to couple all three parts of the system to one another. The Mississippi Bight/Sound model has been calibrated against water level data for the January – April 2000 period at several stations across Mississippi Sound. A more comprehensive model calibration/validation effort will also be discussed.

The resuspension characteristics of cohesive bed sediment samples were assessed through laboratory experiments using a device called the "shaker." The samples were reconstructed in the laboratory from sediments obtained from ocean, estuarine, and riverine beds. Each sample was subjected to a series of increasing shear stresses, with each shear stress being maintained for a certain period. For each experiment, it was found that after a certain time into the resuspension process, the turbidity in the overlying water column reached a steady state indicating that net erosion at that time was equal to zero. The experimental observations affirm the theory that the bed armors after a finite amount of sediment has been resuspended into the water column due to the presence of underlying consolidated layers of greater shear strength. This prevents the underlying layers and particles from being exposed to the flow. At this point, the bed becomes armored. The steady state concentrations as well as the pre-steady state sediment concentrations in the overlying water column are influenced by the characteristics of the sediment bed and notably by the consolidation period of the sediment layers. For increasing bed shear stress, a longer time is required to attain steady-state concentrations in the water column. This is due to the variation in sediment strength with depth of the bed.

We analyzed relationships between Index of Fish Density (IFD) and man-made disturbances, watershed parameters, habitat parameters, water quality parameter, and climate parameters for the 61 HUCs (Hydrological Unit Code) at the macroscale for the South Fork Clearwater River basin in Idaho and 15–20 reaches for Red River and Newsome Creek within the South Fork Clearwater River Basin. Assessment results show that consideration of only the watershed-wide parameters and man-made disturbances is inadequate and yields uncertain results. On the other hand, focusing on a specific stream site alone does not account for all significant parameters. Incorporating both fine and coarse scale parameters in any assessment model will improve the correlations and lead to better results.

The major failure mode of a bridge results mainly from hydraulic deficiencies in the design. Flow conditions through bridge openings should be investigated to observe the degree of hydraulic conformity for the given structural system. A computer program is developed to carry out hydraulic and structural computations jointly for bridges crossing rivers having irregular cross-sections with flood plains. The program has analysis and design options. In the analysis part of the program, steady state water surface profile through a specified bridge opening is obtained. Four different types of bridge opening, which are characterized by geometric features of abutments and embankments, are considered in the program. The energy and momentum approaches are used in the flow analysis. The program is capable of performing computations for low and high flows through the bridge opening. The analysis option can be executed under various discharges to observe the possibility of upstream choking, formation of hydraulic jump in close vicinity of the bridge opening, and to estimate the maximum depths of scour around bridge piers and abutments. The design part of the program is based on the determination of slab deflection, number of piers, sizes of piers and abutments and depths of footings of piers and abutments. The specifications of the American Association of State Highways and Transportation Officials (AASHTO) and Turkish codes are used in the structural analysis. With the use of the program, various combinations of span lengths and pier sizes can be tested from hydraulic and structural safety viewpoints. An application is presented to illustrate the use of the program.

In the present world of multi-dimensional hydrodynamic and sediment transport modeling, engineers often forget that projects utilizing sediment transport modeling are most often performed using one-dimensional (1-D) models. Application of these 1-D models requires not only an understanding of basic hydraulics and sediment transport mechanics, but also the use of finesse and, to some extent, artistry. Finesse and artistry cannot be taught explicitly, but rather are obtained through a combination of understanding the limitations of 1-D modeling in a 4-D real world, a sense or feeling of how rivers work, and experience. This paper presents a list of items 1-D sediment transport modelers should explore, execute or at least think about when they perform a sediment transport analysis.

The top surface of most waste disposal piles including uranium mill tailings piles consists of erodible soils capable of vegetative growth. Usually, uranium mill tailings caps have a design life of over 1,000 years or so whereas those of other solid waste piles may have a shorter design life. During this relatively long design period, unpredictable climatic events, such as local intense precipitation and wind blasts, tend to alter the surface configuration of the pile cap. This may lead to concentration of overland flow in randomly formed depressions, gully formation, and potential exposure and transport of tailings with surface runoff. This paper describes the design of a uranium mill tailings pile surface, which consists of berms, lateral flow channels, and swales and minimizes potential for gully formation. Surface runoff from the pile surface is discharged to a downstream channel along a riprap-protected portion of the side slope of the pile.

A modeling study was conducted to examine the effect of high resolution grids on modeling results by analyzing the hydrodynamic characteristics of Newark Bay, New Jersey and the adjoining rivers. Simulations were performed by using a state-of-the-art three-dimensional hydrodynamic model, ECOM. The modeling framework for these simulations was similar to the System Wide Eutrophication Model (SWEM) developed by Blumberg et al., for the New York/New Jersey Harbor system. An orthogonal, curvilinear grid used for the SWEM model was further refined to allow for a higher resolution representation of Elizabeth Channel, Port Elizabeth Channel, Newark Bay, Arthur Kill and Kill Van Kull. The model forcing functions consist of water level variations, temperature and salinity along the open boundaries, atmospheric and meteorological conditions, and freshwater inflows from five rivers and 198 combined sewer outfalls (CSO). The forcing function data for the present model were provided by the SWEM model for the six winter months, from October 1, 1994 through March 31, 1995. Model calibrations were performed against observed temperature and salinity at six stations and water level data at three stations across the model domain. The model results for temperature and salinity indicated close agreement with data throughout the model domain especially near the Newark Bay, Arthur Kill and Kill Van Kull areas where higher resolution grids were adopted. The model was able to reproduce the observed water surface elevations at Sandy Hook, Battery Park and Bergen Point very well. The present model also predicts the seasonal variability and stratification of temperature and salinity very well.

The Calcasieu-Sabine Basin is located in the southwest corner of the State of Louisiana and extends into Texas. Hydrodynamics of the Calcasieu-Sabine Basin involves a combination of estuarine processes such as saltwater intrusion and response to water level fluctuations at an open boundary, and lake dynamics such as strong response to wind forcing particularly water level setup and the development of high velocity currents in near-shore shallow regions. The basin is also affected by deep ship channels that are strongly salinity stratified, and therefore a three-dimensional model is more desirable for simulating the basin. A robust, flexible and efficient numerical model is required to incorporate all of these processes in an operational program. The three-dimensional finite-difference hydrodynamic model (H3D) was used to simulate the hydrodynamic characteristics of the Calcasieu-Sabine estuarine system. The model was calibrated and validated using a one-year record of data representing a full seasonal cycle of water level and salinity measurements at different measuring stations strategically located within the basin. Graphical comparisons and error analysis of the results illustrate the capability of the numerical model to produce accurate simulations of the complex flow patterns of the Calcasieu-Sabine Basin. Since H3D is based on solving the three dimensional mass, momentum and density conservation equations, it can be used to simulate flow and salinity patterns for the basin outside the range of the calibration field data for different hydrologic conditions. The model can also be used to simulate the effects of human induced hydrologic changes in the basin such as the addition of hydraulic structures, widening or deepening of navigation channels, or changing the volumes of freshwater inflow to the basin. Thus, the model provides a very useful planning and adaptive management tool.