Watershed Management and Operations Management 2000

The Arizona Watershed Program was formulated in the early 1960s by the State Land Department and the Arizona Water Resources Committee to work with the USDA Forest Service, their cooperators, and others to obtain and extrapolate research findings related to watershed management practices designed to increase water yields by manipulations of vegetative cover; to measure both the positive and negative effects of these vegetative manipulations on all natural resources; and to make economic evaluations of these manipulations. The Arizona Watershed Program was initially planned to find a solution to the age-old problem of conserving rainfall by putting every drop to a beneficial use. An abridged version of the history of this program is presented in this paper.

A lot of time and resources have been devoted to research in rangeland hydrology over the past 40 years. What have we learned? Natural variability in precipitation and rangeland watershed characteristics necessitate the results be applicable over both spatial and temporal scales. This requires that data be collected over a sufficient area and time span to evaluate not only the normal storm event but maybe more importantly, the extreme (large) events. While there have been some changes in the research approaches of the past 40 years many of the present concepts in rangeland and watershed hydrology have not changed since the 1970s. Are these approaches still valid? There has been very little effort directed toward developing new understanding of the processes, which make up the hydrologic phenomena on rangelands. New principles must be developed from rangeland settings, not adaptations from cultivated agricultural or forested watersheds.

Effective integration of natural sciences, social sciences, and engineering in watershed management depends on the use of scientific methods and sound engineering practices, but those methods and practices are no more successful than the data, information, simulation models, and knowledge they employ. Currently, more data, information, and simulation models are available than ever before. Although tools, such as relational databases and Geographic Information Systems provide efficient means to interpret and analyze large data sets, improved land management is limited by significant gaps in our scientific understanding of watershed processes and by the limited accessibility of scientifically defensible tools for decision making. There are gaps in basic data related to water quality and land use and management, gaps in the capabilities of simulation modeling and gaps in our knowledge of how to apply models in decision making. Although, significant scientific data, information, and knowledge are available to address watershed management problems, these scientific tools are not useful to the watershed manager unless they are easily accessible, easy to use, effective, and scientifically defensible. Decision makers do not have access to truly integrated contemporary watershed simulation models that satisfy minimum criteria for accessibility, ease of application, effectiveness, and scientific defensibility. This paper presents a synopsis of the technical aspects of a review and assessment of the utility and limitations of the "watershed" approach in research, policy, and management undertaken in 1996–1999 by the National Research Council (NRC). Based on the identified barriers to effective watershed management and the resulting recommendations of the NRC, we propose a framework for developing systematic approaches to watershed management. Adoption of a systematic approach, such as proposed herein, may be a means of overcoming some of the barriers and of moving toward our goal of integrated watershed management.

Many federal agencies are emphasizing the protection, management, and restoration of ecosystems at the watershed scale. A federal interagency analysis process was developed in 1998 to assist field hydrologists with three tasks: delineation of watersheds, organization and storage of information in watershed case files, and assessment of hydrologic condition. The six-step assessment process produces information that is focused on locally relevant cause-effect relationships. The products from the assessment are useful for interdisciplinary interaction and planning, prioritization of restoration or monitoring efforts, and support the development of recovery plans dealing with water quality limited waterbodies (Clean Water Act, section 303[d]) or listed species (Endangered Species Act, section 7). The procedures described are integral to implementation of the Clean Water Action Plan and its associated Unified Federal Policy.

The Upper Animas River watershed in southwestern Colorado is a watershed with historic mining districts with many small mines and mills and a few larger mines and mills. The numbers of trout may be limited by high flows during the spring runoff period and by winter streamflows. In some locations there are large particles on the stream surface that may provide cover to trout, but the presence of fines in the substrate in some areas and the presence of large particles on the surface probably limits use of the subsurface by fish. During some parts of the year metals in the interstecial waters are toxic to many aquatic animas when the stream waters are much less toxic. The concentration of copper and zinc appear to be constant during streamflows that cause the bed material would be moved by the high discharges.

Nonpoint sources of pollution are an increasingly important cause of water quality impairment, and this is forcing water quality regulation towards a more integrated, watershed-scale approach. Nonpoint sources are the dominant source of pollution in forested areas, and large landowners, such as the U.S. Forest Service, are required to assess and minimize adverse cumulative effects on aquatic resources. This paper argues that the current emphasis on changes in runoff is largely unjustified, whereas forest management activities can have relatively large effects on erosion and sediment yields. Although the relative importance of sediment is recognized, current models must be revised to account for the potentially larger, but less persistent, changes in erosion and sediment loads. Geographic information systems can improve our ability to assess cumulative watershed effects (CWEs). However, the accuracy of any assessment will be limited by: (1) the uncertainty of quantifying the effect of each disturbance; (2) the inability to predict indirect effects; (3) unknown recovery rates; (4) problems of validation; and (5) the uncertainty of future events. Adaptive mangement is one alternative approach, but this is unlikely to provide a sufficient level of protection to aquatic resources. Minimizing the local effect of each activity is probably the most efficient means to reduce CWEs, but this should be coupled with focussed downstream monitoring. The assessment of cumulative effects will continue to be a difficult and contentious issue.

Soil degradation in arid and semiarid ecosystems is a significant problem. Knowledge of sediment yield at the outlet of watersheds is insufficient to interpret internal watershed erosion and deposition processes. An integrated system is under development to incorporate databases containing channel cross section information, a sediment yield model (APOINT) that is applicable to individual cross sections along alluvial channels, and interpreted model output. The complexity of sediment transport processes is expressed in the APOINT simulation model. The APOINT sediment transport model was calibrated and validated at small semiarid watersheds within the USDA-ARS Walnut Gulch Experimental Watershed near Tombstone, Arizona. The APOINT model explained about 85 percent of the variation in observed sediment discharge from a 3.68 ha subwatershed located in the upper end of a 43.7 ha watershed. Results of model validation at the same watershed indicate that APOINT is able to explain 98 percent of the variation in observed sediment discharge. APOINT was further calibrated at the outlet of the 43.7 ha watershed by comparing model results with observed sediment accumulation in the pond located at the watershed outlet. APOINT was able to explain 77 percent of the variation in sediment accumulation during 7 time periods from 1962–1996. Following the establishment of APOINT as a viable model for simulating sediment discharge through individual channel cross sections, efforts were focused on integrating the model with a database containing field data collected at several points along the main channel within the 43.7 ha watershed. An integrated system is under development to link the model and the database, provide a user friendly interface, and interpret model results with respect to zones of erosion, transport, and deposition within the watershed. The result is a scientifically defensible, readily accessible, easy to use tool for simulating sediment yield from small semi-arid watersheds.

For effective watershed management, data, technology and science need to be integrated with social, environmental and economic elements while recognising spatial and temporal variability. In Queensland, Australia, the direction in natural resource management is towards transparent, multi-objective, multi-stakeholder partnerships between government, industry and community groups for the allocation and use of watershed resources. This means holistic, transdisciplinary approaches to the sustainable, multiple use of resources are required, and that the process of engaging watershed stakeholders is both effective and efficient. The move towards a systems-based approach to evaluate management options has been facilitated by the development of multiple objective decision support systems (MODSS) to evaluate trade-offs between numerous and possibly conflicting objectives. However, the implementation of such tools requires a methodology to maximise participation by stakeholders and to ensure the decision making process is equitable, constructive and effective. This paper describes the process and initial outcomes where a multi-stakeholder, participatory decision making approach is used to evaluate and prioritise proposed water infrastructure developments in northern Queensland, Australia. The study examines four possible dam sites, each with three spillway heights, and is promoted by the Queensland Department of Natural Resources (QDNR). What emerges from this study is that the outcomes are dependent on the process of facilitation as much as the utility of a multiple objective decision support system. In addition, there is a better opportunity for the stakeholders to identify a "consensus" option when they are involved early in the process, and there is sufficient time to allow the stakeholders to explore scenarios in order to satisfy their concerns and preferences.

New York City's primary source of potable water for its 9 million customers is the 4,095 km sq. (1,581 sq. mi) Catskill/Delaware watershed located about 161 km from the City. The 1986 Safe Drinking Water Act amendments required filtration of all surface water drinking water supplies, unless one could prove that watershed management could keep the water clean. In light of an estimated $5 billion to build a filtration plant for the 5.7 billion L it supplies daily, New York City opted for a watershed approach. A Memorandum of Agreement (MOA), signed on January 21, 1997 is the blueprint for managing the watershed for water quality. The MOA has three main strategies: 1) purchase property from willing sellers, 2) implement watershed rules and regulations, and 3) establish watershed protection and partnership programs. The City has agreed to spend $1.5 billion to carry out the MOA and New York State has pledged $700 million. USEPA issued a Filter Avoidance Determination (FOA) based on the MOA and milestones New York City must meet. Agriculture has a separate agreement.

The Catskill-Delaware region in New York, including Delaware County, has renowned natural beauty and resources, with a valued heritage and culture. It is also includes the watershed area encompassing the major reservoirs of the New York City water supply system. The Cannonsville Reservoir in Delaware County is the third largest reservoir in the New York City Water supply system. Its water quality is determined by two factors: what flows into it each year from the watershed, and how the reservoir is operated. Total phosphorus loads from point and nonpoint sources in the watershed have been measured since 1991. Loads vary from an observed low of 21,000 kg to a peak of 174,000 kg. A typical annual load is likely to be in the range of 50,000–60,000 kg year. Unfortunately, this loading is sufficient to maintain concentrations of phosphorus in the reservoir at 20μg/L or above. In consequence, the Cannonsville reservoir basin is designated as phosphorus restricted. Under this designation, new or increased discharges of waste water to surface waters is prohibited. To protect the economic vitality of its communities and businesses, the County is now compelled to develop a rigorous management program to quantifiably reduce phosphorus loading to the reservoir. Principal sources of the phosphorus delivered to the reservoir include: waste water treatment plants (WWTP); failing septic systems; urban storm water runoff; and manure spreading in the Cannonsville basin. The actual total annual loading of phosphorus from WWTP is estimated to be 7000kg. The estimate of potential annual loading from the 200 septic systems known to be failing is about 2000kg, although the actual number of failing systems is believed to be substantially higher than 200. Total phosphorus in storm water from village drainage could also be as high as 2000kg, and the total phosphorus in animal manure is estimated to lie between 274,000kg/year and 410,000kg/year.

To ensure the continued high quality of New York City's (the City) drinking water supply, the Department of Environmental Protection (DEP) developed a comprehensive long-term watershed protection program. Initiated in 1989, this program has provided the basis for a series of waivers from the filtration requirements of the Surface Water Treatment Rule (SWTR) for the Catskill/Delaware supply. The current Filtration Avoidance Determination (FAD), granted in 1997 by the United States Environmental Protection Agency (EPA), will remain in effect until April 2002 when the City will seek renewal of the waiver. As outlined in the SWTR (and Interim Enhanced SWTR), contaminants of concern fall into several categories: coliform bacteria, enteric viruses, Giardia sp., Cryptosporidium sp., turbidity, disinfection by-products, and watershed control. DEP has developed programs to address each of these. With the signing of the Watershed Memorandum of Agreement (MOA) on January 21, 1997, New York City has entered into a new era of watershed protection and partnership with numerous watershed stakeholders. Along with this enhanced watershed protection effort comes a need for the City to ensure that an adequate water quality monitoring and research program is in place to continually evaluate the effectiveness and improve upon the various initiatives contained within the MOA. As such, the MOA specifically requires that the City and New York State (Departments of Health and Environmental Conservation) assess the overall effectiveness of the watershed program in five (5) years time, or by the year 2002. A monitoring strategy and research initiative emphasizing the "Watershed Approach" to water quality management, has been implemented by the City. One of the primary objectives of the monitoring plan will be to allow for a technically sound assessment of the MOA to be accomplished within the required five year period. This paper presents an overview of how information obtained through DEP's extensive array of monitoring and modeling programs may be used to evaluate the effectiveness of water supply protection measures undertaken for the Catskill and Delaware Systems. The sequence of monitoring, watershed program structure development, and evaluation is described. A more detailed description of this program is presented in DEP's 1998 Filtration Avoidance Supplemental Report.

Basin Analysis Software (B.A.S.) was developed for the complete design, analysis and optimization of side-weirs and flow-by retarding basins. B.A.S. utilizes the quasi-unsteady approach to calculate the hydraulics of the basin-channel system, including side-weir, channel, outlets, storm drain inlets and emergency spillway. Simplifications that typically produce sub-optimal and/or needlessly expensive design are no longer needed. The 10^st Detention Basin in Phoenix, Arizona was analyzed using B.A.S. Next B.A.S. was used to optimize the system. The optimized system could significantly reduce land requirements as well as construction costs.

A computer-assisted method is developed for the optimum hydraulic design of diversion weirs. With a number of relevant input parameters and a known design irrigation discharge, which can be estimated according to the project requirements of an irrigation field composed of a desired crop pattern, the overall dimensions of a diversion weir are determined. The program tests various combinations of dimensions for the structural elements, ie. intake, settling basin, spillway, energy dissipater, etc., within the recommended ranges of hydraulic requirements. The alternative with the desired hydraulic performance and having the minimum total cost is then proposed. The use of the program enables a designer to compare several alternatives in terms of hydraulic conformity, structural safety levels and cost. An application is presented to illustrate the capabilities of the program.

Miami-Dade Aviation Department (MDAD) began a $5.4 billion capital improvement program (CIP) at Miami International Airport (MIA) in 1990. A key element in the planning and environmental permitting is the Stormwater Master Plan (SWMP) for the 5 square mile airport in urban Miami. The SWMP included comprehensive evaluations of hydrology, hydraulics, water quality, Best Management Practices (BMPs), and facility planning in phases to allow cost-effective implementation of the CIP while aircraft operations continued and increased to serve growing air traffic demands. A variety of constraints were identified including the protection of aircraft passenger safety (no fog or bird attractants) and the environment (water quality, manatees, and hazardous material cleanups). Aircraft passenger safety issues regulated by the Federal Aviation Administration (FAA) had to be balanced versus the environmental requirements of the United States Environmental Protection Agency (USEPA), South Florida Water Management District (SFWMD), and Miami-Dade Department of Environmental Resource Management (DERM). MDAD has proactively implemented a BMP Treatment Train, which includes a series of activities to reduce nonpoint source pollutant load generation and to remove pollutants from the runoff prior to discharge. The BMP Treatment Train has been shown by water quality monitoring to cost-effectively treat runoff from the airport to meet federal, state, and local standards and permit requirements. Implementation has been coordinated with a $5.4 billion CIP to allow timely and appropriate retrofits to the system. This paper presents an overview of the MIA Stormwater Management Program and a summary of the successful implementation of the BMP Treatment Train.

Withdrawal or mining of sediment from a river bed causes local hydraulic discontinuities in close vicinity of the section of withdrawal operation. Duration and magnitude of the rate of channel mining in conjunction with the local flow and bed material characteristics have a direct influence on stream bed equilibrium. The response of a stream against such an operation needs to be searched to examine the time-dependent variation of bed levels that may alter the bed stability and may pronounce local scour problems around nearby bridges. A flexible and user friendly computer program is developed for the analysis of one-dimensional quasi-steady morphologic changes around bridges on rivers having rectangular cross-sections with no flood-plains. The program is executed to observe the effects of governing variables on the phenomenon. With the application of the program, a designer may assess outputs concerning the foundation stability of bridges against channel mining operations.

The TR-20 computer program originally developed for the Soil Conservation Service in 1964 has been completely rewritten recently. The TR-20 rewrite involves a system of programs including not only a new watershed scale surface water hydrology model with expanded features but also a data converter for old input data, a HEC-RAS cross section reformatter, an input editor, a graphical post processor and eventually a Geographic Information System (GIS) based input generator. The rewritten TR-20 model has a more physically based input philosophy than previous versions and is based on the approach in the AnnAGNPS (Annualized AGricultural Non-Point Source Pollution) model. Most of the maximum number limitations have been removed from the model as well. Input has been expanded to include the flow path for time of concentration and curve number weighting calculations from Urban Hydrology for Small Watersheds (TR-55) as options. The data converter converts as much of the old input data as practical to the new format. The HEC-RAS reformatter can provide the needed stream cross section rating information in the TR-20 input format. The GIS based input generator can be used to develop input from Digital Elevation Models, soils, and land use information data layers. Converted data or GIS generated input can be used in conjunction with reformatted data as a starting point in the input editor to complete the input data. The post processor provides graphical display of model input/output that can be incorporated into reports or other documents.

Local watershed project sponsors, assisted by the USDA Natural Resources Conservation Service (NRCS), have constructed over 10,450 upstream flood control dams in 46 states under the PL-534, PL-566, Pilot, and RC&D water resource programs. Some of these projects are reaching the end of their 50-year design life. Many have significant rehabilitation needs. Some dams pose a threat to the public health and safety of community residents while others have potential for creating adverse environmental impacts in downstream floodplains that have been protected by the dams for the past 50 years. These watershed projects, which represent a $14 billion infrastructure investment, have provided flood control, municipal water supply, recreation, and wildlife habitat enhancement on over 130 million acres in every state in the nation. They have reduced flooding to prime farmlands, highways, homes and businesses and have become an integral part of the communities they were designed to protect. Many project areas are now in a far different setting than when they were originally constructed. Population has grown, development has occurred upstream and downstream from the dams, landuse changes have taken place, sediment pools are filling, structural components have deteriorated, and many do not meet state dam safety regulations that have been revised with more stringent requirements since the dams were built. A major challenge exists as more than 2,000 dams need rehabilitation at an estimated cost of more than $540 million. Public safety, environmental concerns, funding, and liability are just some of the issues that must be addressed before these dams reach the end of their design life. There is currently no federal statutory authority for rehabilitation of these projects, and most local sponsors do not have the financial capability to address work needed to continue to protect their communities.

Sergeant Major Creek Watershed is one of the oldest projects in the Washita River Basin in western Oklahoma. The Washita River Basin is one of the original eleven watersheds in the nation authorized by the Flood Control Act of 1944 (Public Law - 78-534). Since 1948, local watershed project sponsors, assisted by the USDA Natural Resources Conservation Service (NRCS), have constructed 1,140 upstream flood control dams in the Washita River Basin. Many of these dams are now reaching the end of their 50-year design life. Many have significant rehabilitation needs. Some dams pose a threat to the public health and safety of community residents while others have potential for creating adverse environmental impacts in downstream floodplains that have been protected by the dams for the past 50 years. Action is needed to rehabilitate these dams so they continue to provide the many community benefits for another 100 years. In 1998, the Sergeant Major Creek Watershed was selected as a national pilot rehabilitation project. This watershed includes six upstream dams that provide flood control to downstream agricultural areas and the town of Cheyenne, Oklahoma. Planning of the rehabilitation project has been completed. Designs have been completed for rehabilitation of two of the older flood control dams. Reconstruction of one of the dams is complete, and construction has begun on the second dam. The Sergeant Major Creek Rehabilitation Project is a good example of the typical needs that exist in many of the more than 2,000 watershed projects nationwide. Many of these projects are now in a far different setting than when they were originally constructed. Population has grown, downstream development has occurred, land use changes have taken place, sediment pools are filling, structure components have deteriorated, and state dam safety regulations have changed since the dams were originally constructed. This paper will describe the background of the Sergeant Major Creek Rehabilitation Project, the rehabilitation planning process used, the design of upgrading two of the dams, and the concurrent locally-led planning process used to address other resource needs in the watershed. Recommendations for future rehabilitation projects are also included.

Over the years, the Natural Resources Conservation Service (NRCS), formerly the Soil Conservation Service (SCS), has developed several definitions for the moisture condition of a watershed before a rainfall/runoff event occurs. In 1964 SCS published the concept of using the five-day antecedent precipitation as an index of the watershed condition prior to a major storm. NRCS published the initial concept in the National Engineering Handbook Section 4 (NEH-4), which related the magnitude of the five-day precipitation to three watershed conditions of dry, average and wet. This association was published in Table 4.2. conditions were dry, average and wet. The latest revision of Chapter 4 in 1993 does not include the relationship of five-day antecedent precipitation to watershed conditions. The three watershed conditions are now described in Chapter 10 NEH-4 with the same classifications. NRCS now uses antecedent runoff conditions rather than antecedent moisture conditions. NRCS has determined that the prior five-day precipitation is not the best indicator of the antecedent runoff conditions.

The USDA Forest Service manages the National Forests and National Grasslands. The National Forest System is over 77 million hectares (190 million acres), an area the size of Texas and Kentucky combined. It is nearly impossible to visit or manage these lands without using roads. The Forest Service Road System (FSRS) of over 600,000 kilometers provides most of the access. The bulk of these roads do not meet today's standards for safety and environmental protection. The system is poorly maintained. Roads are probably the single largest source of sediment in the National Forests. The roads are also one of the largest sources of Forest controversy. The goals of the National Forests can not be met unless the problems of the road system are addressed and resolved.

We believe that the evolving concept of ecosystem management has helped us to take a broader view of the established discipline and practice of watershed management. In watershed management the stream or river catchment is an integrated unit of physical and biological components linked by the delivery, storage, transport, and use of water. Ridgeline is linked to midslope, which is linked to bottomlands, which are linked to the aquatic zone. Water carries nutrients, assists in the spread and nourishment of organisms, and is a key agent in the formation of topography and soils that support a watershed and its ecosystem. As with any linked system, management actions that affect any single part of an ecosystem are, in turn, likely to impact other parts of that system. Traditionally, Watershed Management has focused on water quality and the human activities that affect it. Ecosystem Management broadens that focus to emphasize, equally, other elements of the forest ecosystem that often have been ignored or overlooked. From this expanded viewpoint, we are able to recognize problem sources in the ecosystem context rather than just the symptoms as manifest at isolated points in the stream.

As the Forest Service's Natural Resource Agenda was being forged, the transportation system and its relationship to the other elements of the Natural Resource Agenda: Watershed Health and Restoration, Sustainable Forest Management, and Recreation became so clear that Roads were made a part of the Agenda. As a part of "... providing all Americans with access to the National Forests." on January 28, 1998, the Forest Service proposed a rule in the Federal Register to suspend road construction in certain unroaded areas. A part of that proposed rule indicated that it was necessary to prepare a `New Science Based Road Analysis Process to assist National Forest Managers reevaluate the transportation system to assure that it is responsive to new focus on ecosystem restoration, the publics need for access to the National Forests and to assure that the transportation system can be maintained and operated with existing and expected funding. The Road Analysis Process was prepared by a team of senior scientists and managers to meet the requirements of the final rule.

Heat is a major pollutant of stream waters on Western rangelands. To comply with the Federal Clean Water Act of 1972, Total Maximum Daily Load (TMDL) allocations for heat or elevated stream temperature are being developed for stream systems throughout the Western states. Monitoring compliance to water quality standards is currently done using ground-based methods which are inadequate for the task. Regulatory decisions are often based on only a few point samples per major tributary. This limited sampling provides very little information about the dynamics of stream temperature and its potential effects on beneficial uses (e.g., cold water biota) throughout a stream system. A remote sensing technique is needed to practically and efficiently provide stream temperature information for entire stream systems. Stream shading by riparian vegetation can strongly influence stream temperature by reducing solar heating. Estimation of stream shading using remotely-sensed parameters such as the canopy structure of riparian vegetation has been suggested as a possible surrogate for direct stream temperature measurement In this study, supervised classification of airborne multispectral videography was evaluated as means of assessing the canopy structure of riparian vegetation within Reynolds Creek Experimental Watershed in southwestern Idaho.

Steep, rugged hillslopes and headwaters drain a wide valley through which flows the South Fork Skokomish River. From natural flood plain features in the lower valley to mountainous terrain encompassing the majority of the watershed, this area has a diversity of habitats defined by elevation, topography, soil type and precipitation. Most of the 83,000 acre watershed is used for commercial timber production and is managed primarily by the USDA Forest Service and Simpson Timber Company. The valley is used for agricultural and residential purposes, and is home to much of the Skokomish reservation. Logging began in the valley around 1860. Timber harvest methods and machinery capabilities limited logging to areas adjacent to mainstem Skokomish river. Floating harvested logs down the river, referred to as a log drive, came into practice. Railroad based systems were used extensively during the years of 1935 through 1949. Construction of roads began in the 1940's and clearcut harvest of steeper slopes became possible. Road density is 354 miles of road on National Forest lands and 116 miles of state, county or private roads. Road densities vary by subwatershed from 0 to 5.9 miles per square mile. Fifteen of the 21 subwatersheds have higher road densities than the 2.5 miles per square mile recommended by the Washington Department of Fish and Wildlife for minimizing disturbance to big game. The Olympic National Forest also uses this number as a "red flag" indicator of cumulative effects issues.

Increasing emphasis on improvement of degraded wetlands and riparian areas in the western United States has necessitated development of appropriate plant materials and planting technology. Treatment of damaged wetlands requires restoration of proper hydrologic functioning and reestablishment of native vegetation. Restoration of native vegetation is necessary where remnant plants, vegetative materials and seeds are absent. Flooding, sediment deposition and removal and fluctuating ground water levels present challenges in the selection of appropriate species and classes of planting stock. These decisions are made more difficult as genetic variability, transfer guidelines and requirements for establishment of wetland species are largely unknown. Limited information on propagation techniques complicates production of nursery stock, planting and direct seeding. USDA Natural Resources Conservation Service Plant Material Centers in the western United States are developing source-identified material of common wetland species adapted to specific geographic areas. They are also designing revegetation equipment and formulating planting guidelines. Private, state and federal nurseries are producing increasing quantities of site-adapted planting stock for wetlands. Results of recent research on propagation and establishment of selected wetland species are beginning to appear; their application should improve the success of wetland plantings.

An historical account of hydrological conditions of the Rocky Mountain Region is used to describe streamside vegetation as observed by Lewis and dark and other early explorers. These pre-settlement conditions are compared to riparian conditions that now exist to demonstrate what agriculture and engineering has accomplished to enhance the fishery, wildlife, and recreation resources of the Western U.S. Proof will be presented to demonstrate that ranches alone have enhanced riparian wetland systems and developed off stream water in such a way that they are now a major player in the proper control of nonpoint pollution from western rangeland. Because of land ownership patterns and permitted rights to water resources, maintaining the integrity of their ranching operations is essential to insure present resources remain in place to promote fishery and wildlife habitat, food and fiber, and continue to control nonpoint pollution from entering the streams of the western United States.

Managing at the watershed-scale has become an increasingly popular and innovative approach to water resources management. As watershed based approaches to managing water resources are being adopted throughout the United States, knowledge is accumulating rapidly in different regions about what works and what does not. While there is considerable enthusiasm for spreading (and replicating) these "lessons learned" nationally there is also the recognition that institutional arrangements for watershed management should reflect the unique physical and social characteristics of each region. These observations raise the following questions: To what extent (and under what circumstances) can the knowledge gained in one region be constructively applied elsewhere, and what opportunities and risks are associated with the transfer of "lessons" among regions? These are deceptively difficult and salient questions only recently receiving serious attention in the context of watershed management. In this paper, we choose to examine a small component of this issue by considering watershed management approaches in the disparate states of Massachusetts and Arizona. These are regions with very different biogeophysical qualities, legal and administrative regimes, major water uses and issues, and community governance traditions. In short, they appear to have little in common. In practice, however, state watershed management plans in the two states are quite similar. Understanding the reasons behind this outcome is useful in explaining the limits of the transferability of lessons.

The field of watershed management is a rapidly evolving area in which the participants are recognizing that sound tools for managing people and institutions are just as important as the tools for managing the technical aspects of a problem. In fact, the call for abstracts for this conference acknowledged: "It is more important than ever to ensure that the best possible management, information and technology options are being implemented." The Los Angeles and San Gabriel Rivers Watershed Council has developed a comprehensive vision statement which describes how the watershed will look in the future because they believe it is a critical step in their ability to manage the watershed. A wide variety of stakeholders all agreed that a clear picture of where they were going was paramount if their efforts were to be successful. This paper describes the history of the Council, its membership, the process they went through to develop their vision, and the steps they've taken towards implementation. It emphasizes the importance of the Council's role as a facilitator of multiple stakeholders within the watershed, rather than the creation of a new organization. It describes the critical role that regular Council meetings play in developing trust among stakeholders, educating stakeholders from a wide political and technical background about technical issues, and building champions within governmental and other organizations about the need for watershed management. It stresses the need for consideration of management tools such as consensus building, teamwork, and conflict resolution, as well as good old-fashioned patience and long-term commitment from individual's as well as organizations.

Institutional structures that address watershed problems across political boundaries may often, although well meaning, fall short in their ability to adequately address and resolve these issues or may simply be absent. With the assistance of the Alabama Department of Environmental Management, the Water Works and Sewer Board of the City of Gadsden (Alabama) and CH2M HILL, Inc., are developing a River Basin Management Program that will establish a benchmark organizational process to address basin-wide concerns while allowing local watershed issues to be addressed, as well. With drivers from the improved general health of the watershed to the potential of significant capital cost savings for municipal and industrial users to comply with total maximum daily load requirements, local stakeholders should be able to collectively identify, prioritize, and direct necessary watershed projects. The proposed River Basin Program consists of a Steering Committee that establishes goals and objectives for the river basin, an Advisory Committee that oversees activities within and coordination among the river sections, and local watershed committees that address local concerns. Although this River Basin Management Program focuses on water quality issues in the Coosa, Tallapoosa, and Alabama River basins, the goal is to create an organizational framework that can be used as a model for the other river basins within Alabama. State regulators anticipate to use this framework as a long-term approach to address their water quality concerns.

The watershed of the Mystic River (eastern Massachusetts) is a heavily developed area with a long history of water quality problems. First settled by Europeans in the 1600s, the watershed has been used for farming (c.1630–1920), industry (c.1850–1950), and residential and commercial development (c. 1920–present). The main water quality problems include sewage-borne bacteria, chemicals leaching from old waste disposal sites and from contaminated sediments, excessive inputs of plant nutrients, and pollutant loadings in stormwater runoff (e.g., fuel hydrocarbons, road salt, toxic metals). As the population of the watershed has increased, interest has grown to improve water quality enough to allow recreational activities such as swimming and fishing. This paper explores the history and causes of water quality problems on the watershed with the goal of helping to prioritize problems should be addressed as part of an overall watershed management strategy. Understanding the history of water quality problems in a watershed is essential to avoid repeating past abuses and to foresee future challenges for improving water quality.

The Mystic Watershed Collaborative (MWC) is a long-term partnership between the Tufts University WaterSHED Center and the Mystic River Watershed Association (MRWA) to contribute to restoration of watershed ecosystems, improvement of water quality and flood management, provision of public access to the river, public awareness of watershed problems, and encouraging new forms of governance that will be more effective than the current fragmentation of responsibility among state agencies and local municipalities. Presented in this paper is a summary of the Mystic River watershed and the MWC.

At the University of Washington College of Forest Resources, we have established various pathways to improve the training of students who will work on watershed issues. At the undergraduate level, the College of Forest Resources offers a minor in Streamside Studies and the undergraduate curriculum in Forest Engineering has been reformulated to include options that emphasize natural systems. The minor consists of 1 course in each of 5 core topics, hydrology, ecology, fisheries, geomorphology plus a weekly seminar organized by the Center for Streamside Studies that covers a wide range of topics related to watershed management. Students then take additional credits to gain in-depth knowledge in physical, biological or social systems. At the graduate level, the Forest Engineering and Hydrology program uses a capstone design class to train students in watershed design. The class emphasizes the use of design principles as developed by Nam Suh. Students work in groups with a client to develop well-defined Functional Requirements (FRs) and Design Parameters (DPs). These principles are then put into a context of ecological engineering. This leads to a design process that includes an appreciation for the relationship of organisms (including humans) with their environment, and the constraints on design imposed by the complexity, variability and uncertainty inherent in natural systems. This paper will discuss the development of these programs and what changes we think are necessary in engineering education.

Most common soil erosion models were developed for agricultural conditions and then modified for rangeland, forest, and other applications. Rill and interrill erosion generally dominate upland agricultural erosion on recently tilled fields. In rangelands, soil is not tilled, rainfall is sporadic, infiltration is high, and the soil surface is covered by vegetation residues and sometimes rocks. Recent research has shown that as rangeland plant species change from the tall grass species that once dominated many plant communities, to short grass species through overgrazing, the hydraulic conductivity of the soil decreases and runoff increases. The net impact of the rangeland surface and plant changes is that upland erosion may be low, and the dominant source of sediment from rangelands may be from channels. This paper describes a study in southeastern Colorado on sedimentation from rangeland watersheds. The observed rates are compared to predicted erosion rates from a locally developed erosion model, RUSLE, the WEPP model with typical rangeland vegetation and soil scenarios, and the rangeland predictions from the Forest Service WEPP interface and database. The local regression model and the Forest Service WEPP interface best predicted sedimentation from small rangeland watersheds. RUSLE overpredicted sediment yields by a factor of 3, and the WEPP rangeland predictions were 1/6 the observed sediment yields. In a sensitivity analysis with the FS WEPP interface, as cover increases, differences in runoff and erosion between soils decreases.

Past mining activities in the Kantishna Hills area of Denali National Park and Preserve have resulted in a variety of disturbances to the ecosystem. Intensity of disturbance varies from bladed scrapes or wheeled tracks through the tundra to the disruption of the entire system of physical, hydrologic, and biologic relationships in a watershed. Placer-mined streams in the area are characterized by unstable or excessively confined streambeds, with little or no riparian vegetation. Increased sediment loading from such unstable streams results in additional problems downstream, such as cementing of substrates and clogging of benthic invertebrate habitat. Evidence indicates that the value of riparian habitat for wildlife in mined drainages of the Kantishna Hills is severely reduced where a large amount of riparian vegetation and soils are absent. caribou Creek has the most extensive placer mining related impact of any drainage in the Kantishna Hills. It was dredged in the 1930's and then aggressively reworked over most of its length in the 1970's and 1980's with heavy equipment. Approximately 146 ha comprising 21 km of aquatic and riparian habitat have been disturbed by mining activities. Due to recent land acquisitions, the National Park Service is conducting a comprehensive three-year watershed-based restoration project of the entire Caribou Creek drainage. Restoration of the Caribou Creek watershed will provide a significant increase in critical winter habitat for moose, which rely heavily on browse in the few remaining undisturbed floodplains in the Kantishna Hills. Restoration methods and techniques are desperately needed to alleviate disturbances in subarctic latitudes. Due to unique hydrological conditions, permafrost, short growing seasons, wildlife populations, and other northern characteristics, restoration planners need to modify restoration technology designed for warmer climates. This paper briefly describes previous stream and floodplain reclamation projects in Denali, and outlines the watershed-based approach for restoration of the Caribou Creek watershed.

The purpose of this watershed condition assessment is to guide John Muir National Historic Site (JOMU) in choosing the best combination of land management practices in order to improve watershed conditions and reduce flooding downstream. The assessment is intended to document the effects of land uses on watershed runoff and to suggest opportunities for reducing flooding by improving watershed conditions. Variables of greatest concern at JOMU include vegetation and channel conditions and the presence/absence of stock water detention ponds. The report is structured to present an overview of the study watershed, a description of the runoff model, a brief explanation of the methods and alternative scenarios, and a discussion of the results and the conclusions. The report will describe how watershed processes at JOMU affect the relationship between rainfall and the potential for producing floods and model rainfall/runoff to examine several land management options.

Recent fires have renewed interest in the effect of fire on flooding, sedimentation and effectiveness of various mitigation techniques. Erosion is a natural process occurring at varying rates and scales depending on soil type, topography, vegetation, climate and type of disturbance. Erosion rates in a forest environment are generally small except when the ground surface is disturbed by human or natural causes. First year surface erosion rates after wildfire can vary from 0.1 to greater than 110 Mg ha^–1 yr^–1, often decreasing by orders of magnitude in subsequent years. Wildfires may consume the forest floor, leaving the soil surface exposed to raindrop impact and overland flow. Additionally, wildfires may leave the soil surface in a water repellent condition, reducing infiltration and increasing overland flow. These highly erosive conditions are temporary, because natural and artificial revegetation occur within first two years after the fire. To control this erosion and flooding potential, post-fire rehabilitation treatments such as contour-felled logs, have increased in use during the last decade.

Land managers in southern California have speculated that prescribed burning could reduce the soil erosion generated by catastrophic wildfires. A unique opportunity to test this notion arose when a wildfire swept over an ongoing field experiment measuring hillslope erosion from a prior prescribed burn. Results indicate that 1) fire severity may directly affect erosion response, 2) postfire hillslope erosion levels may return to normal within three years, and 3) prescribed fire may reduce the erosion produced by subsequent wildfires. These results suggest that prescribed fire may be an effective sediment management tool in southern California chaparral brushfields.

Evaluation of the erosional response of 95 recently burned watersheds in Colorado, New Mexico, and southern California to storm rainfall established the factors that best differentiate between debris-flow producing basins and those that produced other flow responses. These factors are drainage-basin morphology and lithology, and the presence or absence of water-repellent soils. Basins underlain by sedimentary rocks were most likely to produce debris flows that contain large material, and sand- and gravel-dominated debris flows were generated primarily from terrain underlain by decomposed granite. Basin-area and relief thresholds define the morphologic conditions under which both types of debris flows occurred. Debris flows containing large material were more likely to be produced from basins without water-repellent soils than from basins with water repellency. The occurrence of sand and gravel-dominated debris flows depended on the presence of water repellent soils.

In June of 1977, the La Mesa fire burned 15,270 acres in and around Frijoles Canyon, Bandelier National Monument and the adjacent Santa Fe National Forest, New Mexico. The Dome fire occurred in April of 1996 in Bandelier National Monument, burned 16,516 acres in Capulin Canyon and the surrounding Dome Wilderness area. Both canyons are characterized by extensive archeological artifacts, which could be threatened by increased runoff and accelerated rates of erosion after a wildfire. The U.S. Geological Survey (USGS) in cooperation with the National Park Service monitored the fires' effects on streamflow in both canyons.

The Pacific Lumber Company (Scotia, California), under the measures in its Habitat Conservation Plan, is required to evaluate the magnitude of surface erosion occurring on their logging roads, and the subsequent effects on aquatic habitat. The evaluation is conducted as a component of watershed analysis, the surface erosion module. A detailed road inventory was conducted in one watershed, with results compared to three erosion prediction methods: the Washington Forest Practices Board method, SEDMODL, and WEPP. The models will be evaluated to determine which can more accurately assess/predict sediment production and delivery from logging roads. The use of these models allows us to evaluate other watersheds that do not have extensive field inventories, more cost-effectively.

An evaluation and measurement of landslide activities are requirements of a Habitat Conservation Plan of the Pacific Lumber Company in Scotia California. These landslide studies are initially completed in individual watersheds. Data from the watershed analyses can then be applied in individual timber harvesting plans at a site-specific scale with some additional fieldwork. Methods applied for this work include a modification of guidelines described in the Slope Stability Guide for National Forests in the United States and the State of Washington Forest Practices Board's Watershed Analysis Methodology. These modifications provide a means of measuring and calculating soil shear strengths that can be included in a stochastic modeling of hillslope stability in each watershed.

The operational and environmental impacts of a conventional and a long-span yarding approach to forest management were simulated and compared in T12N R14E in the Ahtanum valley West of Yakima, WA. The conventional approach produced higher revenues at lower costs as expected, but delivered no more sediment to the stream than the long-span, no-new-roads approach. The explanation for this counter-intuitive result can be found in the density of the road network and its proximity to the stream. The road network produced a tenfold sediment increase over background levels, which might suggest a program of elimination and/or surfacing of existing roads. Analysis of this case, however, suggests that the construction of a ridge-based road network will be both environmentally and economically superior. This approach of integrating cumulative environmental impacts into the landscape scale harvest and transportation planning appears promising for identifying management options for reducing salmonid habitat degradation.

The Clearwater National Forest in Idaho accelerated its road removal (also referred to as road decommissioning or road obliteration) program following floods that impacted the Northwestern United States over the winter of 1995-96. In the wake of the floods, landslides originating on closed or abandoned roads were identified as a major cause of sediment delivery to streams. The primary objective of road obliteration on the Clearwater National Forest is to reduce watershed impacts by reclaiming roads no longer necessary for the Forest's transportation system. Roads are inventoried for stability needs. Redundant (i.e. those not needed for management) and unstable roads become obliteration candidates. Road obliteration is accomplished using heavy equipment to decompact road surfaces, remove drainage structures and fill material from streams and draws, and recontour through unstable areas. Various methods are used to control erosion from work sites and revegetate the obliterated template.

The Clearwater National Forest and the Nez Perce Tribe have initiated a road obliteration monitoring project in order to track the effectiveness of an ambitious road obliteration program on the forest. This paper addresses the methods used in level II monitoring of road obliteration on the Clearwater National Forest. The protocols for monitoring are designed to answer questions related to specific treatments. Monitoring results are designed to provide feedback to the obliteration program on treatment effectiveness. Treatments monitored include: general prism treatments (recontour, outslope, decompaction, or abandonment), stream channel treatments (weirs, bank armor and vegetation), cross drain channels, seeded and planted vegetation, and erosion control blankets. Selected 400 m (quarter mile) sections of obliterated road are monitored for each of the first three years, then at five years and at five-year intervals thereafter. Monitoring methods are described in this paper. Some preliminary monitoring results are also presented.

This study investigated the sediment production from various aggregates. The objectives of this study were 1) to evaluate the erodibility of a range of aggregate surfacing materials and relate it to standard and non-standard specification tests, 2) provide a means of specifying aggregate materials and understand the sedimentation implications, and 3) to provide a relative ranking of the erosive potential of aggregates. To accomplish this, eighteen aggregates from the Pacific Northwest were selected based on quality and geologic parent material. A suite of aggregate specification tests were performed to characterize each aggregate. The sedimentation from a simulated rain storm on a plot representing a freshly constructed road section was measured. Traffic was applied and the sediment production from a simulated storm again measured. The two best indicators of aggregate quality were Sand Equivalent and Oregon Air P20 test results. Knowledge of whether an aggregate was classified as good or marginal was not sufficient to estimate sediment production. The best indicator of sediment production was the percent passing the number 30 sieve.

With the growing public use of the national forests, forest engineers, managers, and planners have had the challenge of maintaining extensive road networks, while minimizing the ecological impacts of those road systems on the environment. Properly spacing road drains for soils, topography, and slope conditions can reduce erosion from road surfaces, subsequently reducing sedimentation risk elsewhere. Knowledge about the amount of soil eroded and delivered from the road system is valuable when making decisions about road drainage design or redesign. The Water Erosion Prediction Project (WEPP) model, a process based erosion model that can be used to simulate low volume road erosion, was used to create a database of erosion estimates for 72,900 different road configurations, locations, and soil types. This database was then used to derive equations for low volume road erosion and runoff. A multivariate regression was used to derive equations for road soil loss, road runoff, and sediment yield. The resulting equations provided estimates of road soil loss and road runoff values within +/– 20% of the original database values. This approach was also attempted for sediment delivery across a buffer with less success. This is possibly due to complications from antecedent moisture conditions, vegetative cover, and sediment loading in runoff.

Soil erosion is one of the key concerns in forest resource management. Human activities often aggravate sediment production and transport, leading to significantly elevated sediment levels in forest streams and adversely impacting stream water quality, channel stability, and aquatic habitat. Presently, the health and viability of fish stocks in the northwest US is becoming a critical issue for the government and the general public. Improvement of our understanding of forest soil erosion is of pressing importance. The main purpose of this study is to evaluate forest road erosion processes using a modeling approach. A refined version of WEPP (Water Erosion Prediction Project), a physically-based, distributed-parameter erosion prediction model, was chosen as the foundation for the modeling effort. A segment of an insloping forest road with an impoundment or surface cross drain structure, together with the roadside ditch channel and a waterway channel below the drainage structure, was conceptualized and modeled as a small watershed. WEPP was applied to simulate gross sediment yield within the watershed and sediment delivery at its outlet. Different road system configurations with respect to the density of the drainage structures along a road and downslope road gradient were examined under climate and soil conditions for a representative forest watershed in Idaho State. Soil erosion and delivery ratios resulting from the two road drainage system designs were compared. In addition, cost analyses based on the standard information about material and labor cost were performed to identify road drainage structure designs that can lead to minimized soil erosion and sediment delivery, while proving economically justifiable. Results from this study show that WEPP is a useful tool in predicting water erosion from insloping forest roads with impoundment or cross drain structures as well as in helping establish optimum road drainage system designs.

CASC2D is a distributed-parameter, physics-based hydrologic model. The original single-event formulation of CASC2D includes two-dimensional diffusive-wave overland flow routing, Green and Ampt infiltration, and one-dimensional diffusive-wave routing in rectangular channels. CASC2D has been extensively enhanced over the past several years. The US Army Corps of Engineers (USACE) is currently using version 1.19. This version has a continuous formulation that includes the effect of soil moisture redistribution on infiltration, calculates evapo-transpiration, and performs soil moisture accounting between rainfall events. Version 1.19 also performs upland erosion based on three sediment sizes, transports the sediment overland to the channel, and routes the sediment through the channel as wash or bed load. Improved overland flow routing routines have been added to increase model stability and decrease run times. Other additions in version 1.19 include a three-layer infiltration algorithm, a variety of channel cross-sections, and integration with the Dept. of Defense Watershed Modeling System (WMS). This version of CASC2D has been rigorously tested, verified, and applied at numerous US Army locations. CASC2D version 1.19 is applicable only in Hortonian watersheds. The model formulation is now being extensively revised to promote its applicability in non-Hortonian or mixed watersheds. The new version includes two-dimensional saturated groundwater flow and one-dimensional vadose zone flow linked to the current overland flow and channel routing routines. Improved dynamic-wave channel routing with hydraulic structures, lakes, wetlands, and detention basins are being incorporated into the model. Future versions of CASC2D will also have a more robust channel erosion and transport scheme, a bank failure algorithm, and the ability to transport sediment through hydraulic structures (i.e., culverts, bridges, etc.). It is anticipated that this new version will be completed in the year 2000. The new model will retain all the features of version 1.19. After testing and verification, the revised model, which is named GEISSHA, will replace CASC2D version 1.19 as the USACE's working distributed, physics-based watershed hydrodynamics model.

Physically-based distributed parameter hydrologic models are very sensitive to rainfall input. Inaccuracies in the space-time description of rainfall are typically amplified through runoff predictions. Rain gages do not represent ground truth for rainfall at the watershed scale because they are truly point samples while watersheds are more sensitive to the spatial distribution of rainfall. The use of rain gage data necessitates spatial interpolation of the rainfall field. Weather radars provide an indication of areally-averaged precipitation within the radar pulse-volume. Unfortunately, there are no unique relations between the radar observables and the rainfall rate. Furthermore, radar-rainfall estimates are contaminated by a host of random and systematic error sources. In this study, we examine the impact of each separate source of radar-rainfall estimation error on runoff predictions from the hydrologic model CASC2D. Two different approaches are used. First, S-band single- and dual-polarization radar observations of the extreme warm-rain convective storm that impacted Fort Collins, Colorado, on July 28, 1997, are converted to rainfall rates using published algorithms. Secondly, a physically based atmospheric model of convective rainfall is coupled with an active microwave radiative transfer model to simulate radar observations of a thunderstorm. This methodology allows direct assignment of radar-rainfall errors. Results address the relative importance of random and systematic errors, including range effects and vertical profile of reflectivity, on runoff predictions. Additionally, simulations driven by rain gage and radar-rainfall input are compared to illustrate the impact of the different sampling characteristics on model performance.

The Watershed Modeling System is a comprehensive graphical user environment for conducting watershed hydrologic analysis. The model was developed by the Engineering Modeling Research Laboratory of Brigham Young University in cooperation with the U.S. Army Engineer Waterways Experiment Station. Features of the WMS include pre- and post-processing support, GIS/CADD links, finite difference/finite element grid generation, 2D data interpolation/visualization, AVI video file animation, use of NEXRAD radar of Battlescale Forecast Models as inputs to 2D spatial models, and the ability to import digital terrain data. Models which are currently contained in the WMS lack water quality components. Current research efforts are underway to fully incorporate the Hydrologic Simulation Program - Fortran (HSPF) into the WMS as well as add water quality capabilities to the 2D distributed CASC2D model. HSPF is one of the most widely used lumped parameter water quality models in the country while CASC2D is a widely used distributed watershed model. The incorporation of water quality into CASC2D and the addition of HSPF into the WMS will provide users of the system with a selection of either a lumped or distributed parameter watershed water quality model. It is anticipated that the addition of the water quality components into the WMS will increase the utility of this state-of-the-art system. The system will be applied to research efforts involving watershed water quality and contaminant modeling.

The Land Management System (LMS) is an initiative of the U.S. Army Engineer Research and Development Center (ERDC) to address technology requirements related to land and water resource management in both military and civil works mission areas. The purpose of LMS is to provide relevant tools and information to land and water resource managers and decision makers to enhance their ability to understand and communicate past, current, and potential impacts of management decisions. This paper provides details of plans to design, develop, and transition LMS as an integrated computer-based capability for solving specific land and water resource management problems at field sites.

The regulatory authority for developing and implementing Total Maximum Daily Loads (TMDLs), as required by the Clean Water Act (CWA), lies with the U.S. Environmental Protection Agency (USEPA) and the States. However, there are a number of Corps of Engineer (CE) activities which will either be affected by, or will be the subject of TMDLs. In addition, the CE is also involved in assisting the USEPA and States in the development of TMDLs. Watershed runoff and receiving water models are frequently used to evaluate TMDLs. This paper provides an overview of the TMDL process, how TMDLs may relate to the CE mission, and watershed and receiving water models used by the CE that are applicable to TMDL analysis.

The State of Illinois is investing in the development of a citizen-oriented watershed simulation environment. This Web-based system will provide users - resource managers, watershed management committees, and other resource professionals - with the necessary simulation models to allow them to compare, evaluate, and adapt strategies according to their economic, ecologic, and social consequences. Phase one of the project entails the development of draft user and programmer manuals that will be used to solicit user feedback and to develop consensus among developers. This document explores approaches that have been used to create end-user based decision support systems. Most of these systems have not been used because they approach development from the perspective of scientists. We argue that designing a system from the perspective of the target user, without regard to available models, is necessary for us to develop a useful product.

Hydrological models are often used to simulate surface water in a correct way to be a good basis for decisions regarding the development and management of water resources. The applicability for integrated watershed management of the lumped conceptual rainfall modelling system NAM (Danish Hydraulic Institute) has been tested. Meteorological data and stream flow measurements were used for six subcatchments in the Belgian River Dender basin (1384 km²). Calibration and validation of the models were performed on the basis of new concepts. Furthermore, different subcatchment characteristics (land use, soil characteristics and drainage conditions) are analysed by using GIS. Then subcatchment characteristics, discharge time series properties and model parameters are compared to allow an assumption to be made for model parameters for ungauged subcatchments. In addition, sensitivity of the results to rainfall data from measurement stations at different distances from the catchment and with different measuring accuracy was studied. Also the importance of corrections on the rainfall time series was analysed. Results indicate that corrected rainfall measurements give more accurate results than the original ones. Moreover, the closer the measurement station to the catchment, the higher the accuracy of the results.

The paper will discuss the interaction of artificial recharge, groundwater pumping, and water deliveries for the water short Irrigation Districts on the Culbertson Canal and Extension in Southwest Nebraska. Frenchman Valley ID and H&RW ID completed comprehensive water conservation plans in 1999. The plans show how canal seepage supports supplemental pumping without mining groundwater in an aquifer plagued by declining water levels.

The U.S. Bureau of Reclamation's (Reclamation) Pacific Northwest Region is working to enhance the ability to integrate surface and ground water hydrological and institutional modeling capabilities for use in the Snake River Basin and other river systems in the Pacific Northwest. The MODSIM model is a generalized river basin network flow model which is capable of distinguishing between natural flow and various storage contract arrangements for water entitlement accounting, including storage ownership, water service contracts, and rent pool/water banking. The USGS MODFLOW groundwater model is applied to the vast East Snake River Plain Aquifer to analyze the long term impacts to groundwater discharge to the Snake River. MODSIM and MODFLOW are applied to the Upper Snake basin to quantify how much water reallocation is needed to accomplish flow augmentation objectives. River and reservoir operation simulation analysis is used to quantify impacts to irrigation water supply, river and reservoir recreation, resident fish and wildlife, and other local water uses from various proposed storage rental and reallocation scenarios for satisfying instream flow requirements for endangered species.

Beginning in 1992, the Bureau of Reclamation and the US Geological Survey formulated plans for the Watershed and River Systems Management Program - a cooperative interagency effort to develop and implement flexible and robust river basin management tools for the benefit of managers and decision makers using a data centered approach. In addition to Reclamation and the USGS, a number of other agencies and universities have made substantial contributions to the success of the program. The effort first received research funding from the cooperating agencies in October of 1995 and has developed effective modeling tools for use on the San Juan, Colorado, Yakima and Umatilla basins in the western United States. Presently evolving applications include the Rio Grande basin in Colorado, New Mexico and Texas and the Truckee River basin in Nevada and California. Among the key tools in this effort are the RiverWare package developed for Reclamation by the University of Colorado's Center for Advanced Decision Support for Water and Environmental Systems (CADSWES), the Modular Modeling System developed by USGS and the Hydrologic Data Base (HDB) which interacts with both RiverWare and MMS and serves as the anchor to the data centered modeling approach.

In recent years, management considerations for reservoirs have been expanded to include environmental and recreational objectives. Uncertainty modeling contributes to better reservoir management by quantifying the uncertainties and determining the sources of significant uncertainty in predicting reservoir and river conditions which affect environmental habitats and recreational conditions. RiverWare employs a first-order, second-moment approach to modeling uncertainty. The method is described in this paper and applied to an example on Lake Mohave on the Lower Colorado River. Comparison of historical forecasts with observed data can provide managers with insight into operational policies which result in greater system uncertainty. Identifying these sources of uncertainty can guide managers in the development of future operational guidelines.

The Bureau of Reclamation's mission is to manage, develop and protect our planet's most valuable natural resource - water, and related resources in an environmentally and economically sound manner in the interest of the American public. This paper describes the latest progress in decision support systems that demonstrate the application of environmental monitoring and forecast information to improve water resource management in the Colorado, and Rio Grande Basins using RiverWare.

The U.S. Bureau of Reclamation Research program (Reclamation), with cooperation from a number of federal and state agencies, universities and private entities is developing a website for generally applicable models which can be used for watershed precipitation and runoff analyses, reservoir and river systems operations, water requirements and related hydrologic analyses. This website builds on, expands and updates the 1991 inventory developed by Reclamation. It is anticipated that the website will contain concise summaries with information on each model which will be helpful to potential users in determining which model they should use for their work and how they can acquire these models. The first goal of the model inventory effort is to provide water resource managers, local officials, stakeholders, model developers and the general public with a forum in which the latest modeling and decision support tools may be shared. A second goal of the inventory is to facilitate communication and exchanges of information not traditionally possible through literature, journal articles, conference proceedings and technical reports. The exchanges and communications include developer and user community interactions, interactions between all levels of governmental organizations (federal, state, regional, local, etc.) and between different enterprise models of business (public, university and private, etc.). The shared contact points between these communities (telephone, fax, mail, etc.), particularly the internet resources (email, ftp, and web pages) should increase the flow of information and feedback between different parties. Improved communication facilitated by the on-line inventory should increase the opportunity for awareness, interaction and dialog. The access to information is no longer burdened by barriers in communication. A third goal for the inventory is to provide a summarized discussion forum for the modeling community.

Contemporary Australian policy for `stormwater quality planning', advocates best practice by adopting the principles of ecological sustainable development. The purpose of the policy is engendering community ownership and reducing stormwater contaminants at the source, reflecting the preventative paradigm. Research into the resultant plans has demonstrated that these best practice notions have not been fully realised. This is attributed to the both the policy framework and the planning rationale which demonstrate the characteristic limitations of a traditional top-down technical response to a social problem. A bottom-up citizen driven `participative planning methodology' is offered. This methodology is an attempt to more fully realise the policy intent and address the complexities of communities' expectations and behaviours that impact water quality. The key activity is to reconceptualise the problem frame through enabling shared understandings of the causes and responses to stormwater.

It is argued in this paper that current attempts at community involvement in planning at the watershed level have not been fully realised. This is demonstrated through implementation research, reported here, of community involvement in urban stormwater planning in over twenty watersheds in Australia. It is concluded that narrowly operationalised technical expertise; implementing officers' values towards communities' capacity to understand complex problems; and the basic technical planning rationale are structural impediments to effective community involvement. Effective public participation in this field facilitates the re-definition of the causes and effects of urban stormwater pollution. Fundamental to the realisation of effective public participation is the recognition of the importance of, and role-played by different forms of knowledge (such as scientific, technical, political, social, local, indigenous, bureaucratic and historical) in this process. For improved policy implementation, the key is recognising that problem definition frames the understanding of stormwater pollution causes and effects and pre-determines the expertise requirements for subsequent planning processes. Effective public participation can result in a shared conception of the issues of stormwater conceptually lifting the problem definition out of the narrowly defined technical arena to a social phenomenon reflecting community concerns and aspirations.

A significant source of nutrient input to water bodies is from grass clippings and leaves (yard debris) washed into drainage systems during storms. Brevard County Surface Water Improvement conducted a study to determine the nutrient release rates from grass clippings and leaves in order to better understand the chemistry and resultant pollutant loading mechanisms. Sixty-gram samples of mixed freshly cut St. Augustine yard grass (Stenolaphrum secundalum) and oak leaves (Quercus sp.) were placed into opaque containers. Coarsely filtered storm/ditch water was added to fill the containers to the 8-liter marks. Samples were allowed to go anaerobic, typical of wet sump best management practice (BMP) structure conditions, and tested periodically after soaking and processing. At intervals of: 0, 1, 5, 9, 14, 22, 34, 50, 70, 130, and 180 days, triplicate bucket sets were agitated to simulate mixing from stormwater influx, then poured through a Number 35, US Standard Soil Sieve, and the liquid analyzed. The solids that remained in or on the sieve were analyzed, and the results compared to those of the corresponding liquid phase. The results presented depict "typical" east-central Florida lawn and leaf litter decomposition and nutrient release rates. This information may be useful in the selection or site design of BMP's for treating nutrients in stormwater, and determining cleaning frequency.

A simple GIS-based transport model to estimate the potential for groundwater pollution by pesticides has been developed within the ArcView GIS environment. The pesticide leaching analytical model, which is based on one-dimensional advective-dispersive-reactive (ADR) transport, has been directly integrated into the GIS with menu interface and display tools to estimate the spatial and temporal distribution of a potential pesticide's emission to groundwater. The ADR model was chosen because it requires readily available data as compared to other non-GIS models and it has the potential to handle multiple soil profile descriptions. The ADR model has been used to assist with pollution assessment such as the location and timing of pesticide spreading on watersheds, or choosing the most effective "Best Management Practices". By embedding ADR modeling capabilities into the GIS, one is able to evaluate the groundwater vulnerability to pesticide contamination on a large scale where variable source areas are responsible for a part or all of the groundwater contamination. To demonstrate the GIS-based contaminant transport model and its capabilities, the program was applied to Mid-Atlantic coastal plain agricultural watersheds, which are particularly vulnerable to agricultural pesticide pollution.

This paper presents the overall approach, preliminary findings, and current status of a watershed pollutant trading project on the Truckee River. The Cities of Reno, Sparks and Washoe County and regional stakeholders (watershed managers) are working together to develop a watershed and water quality model for the Truckee River in order to identify significant sources of point and non-point source pollution and to assess water quality Watershed managers then plan to use the models to evaluate the consequences of various management activities including water right purchases, river restoration septic tank conversions and buffer strips) and their impacts on water quality on the watershed. Based on the modeling results, potential non-point and point source trades are being developed for the Truckee Meadows Water Reclamation facility (TMWRF). In addition, watershed managers are evaluating the cost-effectiveness of point and non-point source trades as they relate to the beneficial uses of the river.

The Watershed Analysis Risk Management Framework (WARMF) was enhanced to calculate the total maximum daily load (TMDL) of acid mine drainage for the Cheat River Basin in West Virginia. The framework divides the river basin into catchments, river segments, and lake layers. Some catchments have deep mines and/or surface mines. These catchments have a soil layer that contains pyrite (FeS₂), calcite, and other minerals. The oxidation of pyrite requires molecular oxygen. The framework tracks the concentration of atmospheric oxygen in soil macropores by the advection due to earth breathing and by the sinks due to organic matter decay and pyrite oxidation. Pyrite oxidation produces Fe²⁺, Fe³⁺, SO₄<sup arrange="stagger">2– and H⁺. These by-products are leached and carried by groundwater to rivers as acid mine drainage (AMD). In surface mines, the AMD is carried by the lateral flow in saturated soil. In deep mines, the AMD is leached down to the tunnel for exit through a portal. Due to low pH, the AMD also dissolves other weathering by-products (Al³⁺, Zn²⁺, and Mn²⁺). Upon entry to surface water, insoluable metals can precipitate as hydroxides. For TMDL determination, the designated use is for aquatic life. To protect this use, the State of West Virginia has specified the water quality criteria for pH, Fe, Al, Zn, and Mn. To calculate the TMDL, WARMF steps down the loading of individual constituents in AMD until the water quality criterion is met.

Long-term water quality monitoring in the lower Truckee River Basin, Nevada, indicates significant increases in most solutes (major ions and nutrients) during periods of low flow. Simple solute budgets for the area suggest that much, if not all, of these increases are due to non-point groundwater inputs derived from natural (e.g., geothermal) and anthropogenic (e.g., agricultural) sources. Total dissolved solids loadings over a 20-km reach may exceed 6,000 kg/d, or approximately 10% of the amount permitted at municipal wastewater treatment facilities upstream. Currently, agricultural water rights are being purchased in the study area, with the partial expectation that a reduction in flood irrigated field crops may result in an associated reduction in non-point groundwater returns, creating opportunities for obtaining pollution credits upstream. Ongoing studies, described here, are designed to characterize the relationship between land-use activities, non-point groundwater returns to the river, and potential impacts to instream biotic communities.

The Federal Clean Water Act (Section 303(d)) mandates that states develop Total Maximum Daily Load (TMDL) plans for water bodies that are on the Section 303(d) list. To be placed on the 303(d) list, a water body must be found to have water quality conditions that limit its ability to meet its designated beneficial uses. The TMDL for a water body is defined in 40 CFR 130 as the sum of waste load allocations from identified points sources and non-point sources within the water body's watershed. The TMDL plan for a listed water body should identify the current waste loads to the water body, the waste load capacity of the water body and then allocate the waste load capacity to the known point and non-point sources of pollution within the water body's watershed.

Both the United States Environmental Protection Agency (EPA) and the Florida Department of Environmental Protection (FDEP) have been actively exploring ways to improve the TMDL program. In Florida, the FDEP has reorganized departmental resources, adopted a watershed management approach, and developed comprehensive TMDL legislation. This legislation clarifies FDEP's statutory authority and establishes administrative procedures for the program. It also acknowledges the limited regulatory authority regarding many nonpoint sources of pollution while providing incentives for reduction via implementation of applicable Best Management Practices (BMPs).

A graphic demonstration of channel / bank deisgn and system level tools.

Large variations were found in the effect of population density on streamflow in a statistical analysis of historical streamflow and climatic data for 39 urbanizing watersheds in the United States. Population density impacts on streamflow were not significantly different among seasons of the year or among high and low-flow classes. However, both low and high flow rates increased with population density growth. Streamflow exhibited greater sensitivity to population density increases in the NC and W regions, than S and NE regions of the United States.

Knowledge of high flood discharges is essential in management and operation of watershed streams. Floods of high discharges often cause flooding of floodplain areas with associated large channel or flow width. Measurements of high flood discharges under these conditions are often difficult to be made. Satellite data images, air photographs and flood marks provide valuable information about the extent of floods and their associated flow width while difficulty arises in estimating the magnitude of the flood. An estimation of the magnitude of high flood discharges is possible based on information about channel geometry. The data needed are flood channel width caused by the flood and channel conditions before the flood. This information is substituted into analytical formula developed based on extremal equilibrium concepts. The extremal concepts include extremal energy dissipation, extremal sediment efficiency and extremal friction factor. It is shown that when the discharge is correlated only to channel width, the three concepts are equivalent. The flood estimate assists in implementing emergency and evacuation plans for downstream residents and structures across flooded channels utilising observations of flooded upstream watershed reaches. The estimation also improves knowledge on flood records and channel hydrology when the approach is applied to historical data.

In September of 1992, rainfall simulation experiments were conducted in Albuquerque, New Mexico, to help define the extent of runoff and sediment yield from high intensity storms. This information was needed in design and planning for Albuquerque's runoff collection system. Although presented in a New Mexico Water Resources Research Institute Technical Completion Report, this information has not been disseminated through other publications. In this paper, the methodology and results of the experiments will be presented. Of interest to the engineering hydrology community are the Green-Ampt model parameters computed from the data and the sediment yields accompany the runoff. Steady state loss rates (infiltration rates) ranged from 3 to 69 mm per hour depending on the experimental plot conditions. Sediment yields were also quite variable ranging from about 15 to over 300 kg per hectare per millimeter of runoff. These results show the wide variability one could expect across a landscape. Such information is valuable for the design of runoff collection systems.

On July 28, 1997, another flash flood hit the main campus of Colorado State University and the City of Fort Collins, Colorado. Flooding in the City of Fort Collins killed five people, injured 54, and damaged or destroyed nearly 3,000 homes and businesses. Flooding on the main campus of Colorado State University resulted in water damage to over 425,000 books in the main library and major flood damage to 25 campus buildings including the Library, Student Center, and Heating Plant. No flood related injures were reported on campus but over $100,000,000.00 (one hundred million dollars) in flood related damages were reported. This paper reviews campus flooding, flood-damage, and precipitation records for documented campus floods of 1902, 1938, 1951, 1992, and 1997. Flood depths for these events are analyzed to predict recurrence intervals and design flood depths at the campus Heating Plant for the 25, 50, and 100-year design floods. Our analysis indicates that the 100-year flood depth at the Heating Plant is 2.3 meters. This depth is close to the 1997 flood depth of 2.13 meters.

In 1968, Congress passed the National Flood Insurance Act as part of a comprehensive program of floodplain management. Flood damages had been rising rapidly in the U.S.; thus the National Flood Insurance Program (NFIP) was created to "reduce future flood damage" for individuals and communities, in return for communities taking the lead in imposing nonstructural flood control (www.fema.gov/nfip/intnfip.htm). In this manner, the federal government would "shar[e] the risk of flood losses" with Americans living in flood-prone areas (U.S. Code, Title 42, Section 4001). Of course, flood risk needs to be quantified and flood plains delineated ìn order to assess insurance premiums. The Federal Insurance Administration (FIA), part of the Federal Emergency Management Agency (FEMA), which administers the NFIP, produces maps of participating NFIP communities that show which areas in the communities face flood risk. The Special Flood Hazard Area (SFHA) maps show "the area of land that would be inundated by a flood having a one-percent chance of occurring in any given year" (www.fema.gov/nfip/intnfip.htm). The flood with a one-percent chance of occurrence in any given year is also popularly known as the "100-year flood." This standard was adopted in the early 1970s in order to standardize areas of risk between communities. Within the 100-year flood plain, development may take place, but must comply with local flood plain ordinances, which, in turn, must comply with federal requirements. The SFHA standard "constitutes a reasonable compromise between the need for building restrictions to minimize potential loss of life and property and the economic benefits to be derived from floodplain development".

In most developing countries, the piece-meal approach often adopted for water supply and food production schemes has not yielded the sustained socio-economic development that is often the primary objective. Such schemes often do not directly involve important stakeholders particularly local communities. At best, they are involved without adequate emphasis on well-focused capacity building for their effective participation. Also other local natural resources are often left untapped during the implementation of the schemes. Where they are considered, their negative impacts are left unattended. The paper will attempt to describe the key features in terms of design, focus, and implementation of the Watershed Management Project currently being piloted in Ghana. The lessons learnt so far will be elucidated with the view of enriching experiences for improving similar projects elsewhere especially in developing countries.

A soil erosion control project is being carried out in East Anatolia, Turkey above some of the largest dams in Turkey; Keban, Karakaya, and Ataturk on the Euphrates River. The project is partly financed by the World Bank and has been underway since 1992. The main goal is to reduce soil erosion and resulting sedimentation of dams and to improve the economic condition of people living in the region. The project is coordinated by the Ministry of Forestry and includes the ministry of Agriculture and the Ministry of Rural Service. The project covers the main basin of the Euphrates River and is divided into three segments: the Lower, Middle and Upper basins. The Upper Basin is generally in the region of Elazig and is directly around the Keban dam; the Middle and Lower Basins are in the regions of Malatya and Adiyaman, respectively. The Middle basin is nearby the Karakaya dam while the Lower Basin is around Ataturk dam. The initial project included 18 sub basins and 54 micro-catchments with an average area of 5000 ha.

Shifting cultivation is the major agricultural activity in hilly area of Bangladesh. Shifting cultivators themselves realize that only shifting cultivation is not at all a sustainable nowadays because of decrease in productivity due shortening of (Shifting) cultivation cycle. It was estimated that about 32,500 ha/yr is used for shifting cultivation in Bangladesh. Soil loss also estimated on the findings of SCWMC, which is about 1.5 million t/yr. By this time with the development of communication, marketing facilities, education and health care etc, change of life style is observed and they exposed to a new aspiration. Jhumias (shifting cultivators) are very slowly transforming their life style near township, road network and/or market. Building nurseries, producing valued fruit crops, working as daily labor, even they join (both male and female) transplanting of rice in the valleys. Accounting the aspiration of the people as well as biophysical condition of the area SCWMC started to work with Jhumia families (Shifting cultivator) to develop participatory micro watershed for a better land husbandry system. In this approach Jhumia families and scientists of the SCWMC are working on the same land with their own attitude for production and learning from each other and introducing better land use on sloping land for conserving soil and as well as sustainable for the family. The approach will lead the farmer to be in permanent farming system as well as benefit of conservation measures such as contour planting, gully control, choosing crops, which are the crucial problems for transferring technology in watershed management.

The Indian economy mainly depends on stability of crop production in rainfed areas, as it contributes to 42.2 per cent of the total food production in the country. The crop productivity in irrigated areas has reached near saturation and scope for increasing area under irrigation is limited. Therefore, the option left is to develop rainfed areas to meet the food requirement of ever growing population. In rainfed areas most of the holdings (80 per cent) are marginal (<1 ha) and small (1–2 ha) and as such the prevailing fragile socio-economic conditions of these farmers have aggravated problems of achieving higher crop productivity in rainfed areas. The research information generated for rainfed areas has shown great potential to increase crop production besides offering better alternatives for non-arable land use. Realising this potential in rainfed areas, the Government of Karnataka (a southern state in India) took a pioneering step in constituting Dryland Development Board to implement the `Watershed Development Programme (WDP) in all the 18 districts of the state on the model of Kabbalanala World Bank Aided Watershed Project. The DLDB is unique in terms of unified approach, integrated development of an area, research linkage and flexibility compared to a number of past attempts to develop rainfed areas. The operational area of these Watersheds varied from 15,000 to 45,000 hectares.

An indicator was designed to represent the sustainability of a reservoir water supply system, and a simulation procedure was established to evaluate the indicator. The indicator was defined by potential water supply and water demand. The simulation procedure includes potential water supply assessment, streamflow simulation, and designed water demand. The procedure was applied to the Tsengwen reservoir water supply system in Taiwan. Three upstream land use scenarios, three water demand cases, and four climate scenarios (current and three climate change conditions) were considered to evaluate their effects on sustainability. Simulation results indicate that the converting forest to agricultural land will reduce sustainability, and climate change will also have negative effects. Considering increase of water supply for coastal area will dramatically decrease sustainability. At the end of this paper, an idea for developing an integrated indicator was proposed for further study.

Argentina is a wide and physically diverse country with a continental area of more than 2,700,000 Km². Its great extension in latitudinal sense establishes several climatic characteristics and rainfall distribution, besides the relief diversity, bringing numerous drainage patterns. More than one hundred watersheds and surface water regions (many of those which surpass the international border) constitute the Argentina's river network. Surface and Groundwater hydrology information of Argentina has been considered as a primary database to define the National Water Resources Information System. 1:2.500.000 scale maps were employed to define the main cartographic database, where points, lines and polygons were digitized. The different surface entities were named numbered and grouped according to a pre-established priority system. Groundwater regions were also incorporated with rocks and aquifer types along the country. A new approach was started during 1998 and finished by the end of 1999. Main concepts and design are described and will be presented at the symposium. More than seventy 1:500.000 scale maps, elaborated by the Instituto Geográfico Militar, were digitized to define a more detail physical structure of the NWRIS. National and international boundaries, lineal and areal water body entities, both permanent and temporary, wetlands, marshes, salt fields etc., were included and codified to allow users to retrieve the physical and descriptive information that has been incorporated. The NWRIS is a watershed-oriented database, considering the river boundaries as a relevant geography nearness for water resources and environment management. ARC/INFO and ARC VIEW software were implemented to define the NWRIS structure, so that governmental offices, private institutions and other organisations and planners related to water resources and environmental assessment obtain, add and integrate different sources of data in Argentina's territory.

For the most effective operation of multi-purpose reservoir at flood period, the forecasting of inflow must be preceded and a rainfall-runoff modeling is necessary for the forecasting of inflow. However, the rainfall-runoff process is nonlinear and complex so many errors can be occurred by uncertain parameter estimation in modeling procedure. In this study, a neural network theory was adopted for modeling rainfall-runoff process, and a real-time inflow forecast system was developed. The models developed in this study were based on the back-propagation algorithm and Cascade-Correlation algorithm for learning. We applied these models to Soyangang River basin, so we could get forecasted inflow values — 1 hour, 3 hour and 6 hour preceding inflows. In case of the back-propagation algorithm, many trials are required to find out the optimum structure, but Cascade-Correlation algorithm can make the optimum neural network structure automatically at a time. We applied this model to the August '95 flood event at Soyangang River basin by using Cascade-Correlation algorithm and back-propagation algorithm. In order to improve the accuracy of the flood forecasting, the filtering technique has been used at the neural network model. As a result, Cascade-Correlation filtering model shows better forecasting capability.

This paper describes the use of Artificial Neural Networks (ANNs) analysis as a computing device for forecasting flood stage in the Nakdong River basin, South Korea. The FR-CGBP, BFGS-QNBP, and LMBP algorithms were used in ANNs training here. The connection weights and biases, parameters that were obtained from training procedures, were used for validation of ANNs. The training pattern that involved LMBP algorithm was found to yield slightly better results by statistical analysis of forecast errors. The validation of ANNs was carried out so as to evaluate model fitness with untrained validation data set. Results indicated that ANNs approach produced forecasts of comparable accuracy to observed flood stage.

There is a continuing need to increase awareness about the contributions of watershed management to conservation, sustainable development, and the appropriate use of natural resources. These contributions are essential to good land stewardship in the 21^st century. Computer technologies can assist in the storage, retrieval, and summarization of watershed-based data on the World Wide Web. Such information is useful to managers when planning and implementing watershed management practices, to researchers when testing and validating predictive models, and to educators when teaching about hydrologic processes. Watershed information from the Beaver Creek watershed in north central Arizona has been incorporated into a Web site to illustrate the accessibility of such data. These particular data represent natural resource responses to watershed management practices in ponderosa pine forest and pinyon-juniper woodland types in the Southwest. Documenting and retrieving images, publications, and reports produced during the Beaver Creek Watershed project using various parameters, such as keywords, dates, and locations, is also part of this Web site. This paper illustrates the procedures used to store, retrieve, and summarize Beaver Creek watershed-based data on the World Wide Web.

The watershed methodology is a natural framework for developing a better understanding of the lifecycle of water and the ecology of the containing regions. It can lead to a cohesive and efficient plan for watershed restoration, but it requires a multidisciplinary approach to the studies performed and the data collected. The implementation of the watershed design also requires a coordinated effort among government agencies and other interested parties, first on the local level, then on an increasingly larger scale. It can work well assuming we find ways to deal with the inherent complexities in communication among the people involved as well as in the synthesis of the many forms of data. In order to promote the collaborative effort that is a cornerstone of the watershed approach, it is important that information is readily presented to the stakeholders. In the past, because of limitations on the ability to impart information, we utilized a methodology that focused on centralized planning and that communicated with involved non-governmental organizations and private citizens only after much of the planning was complete. This sort of passive involvement garnered very little buy in and often resulted in litigation and a consequent increase in government imposed regulations. The focus of this paper is to present an approach to watershed management that incorporates the internet as a tool to help address the inherent communication issues. The internet is an obvious tool to assist us in reducing the level of complexity that is associated with the watershed methodology. It is a tool that allows interagency communication, as well communication with the public at large. It also provides an online way to visually display information, which can aid in removing barriers to understanding. By incorporating the internet as a supplementary tool to other methods, the switch to a more collaborative approach can be made smoothly.

An event-based, kinematic, infiltration-excess, distributed rainfall-runoff model was developed to acknowledge and account for the spatial variability and uncertainty of several parameters relevant to storm surface runoff production and surface flow. The model is compatible with raster Geographic Information Systems (GIS) and spatially and temporally varied rainfall data. Monte Carlo simulation and a likelihood measure are utilized to calibrate the model; allowing for a range of possible system responses from the calibrated model. Using rain gauge adjusted radar-rainfall estimates, the model was applied and evaluated to a limited number of historical events for two watersheds within the Denver Urban Drainage and Flood Control District (UDFCD) that contain mixed land use classifications. The 95% uncertainty bounds obtained from the model envelop almost all observed responses at the main basin outlets for the events considered, suggesting an acceptable model structure. While based on a limited number of Monte Carlo simulations and considered events, for the two basins that were considered, Nash and Sutcliffe efficiency scores of 0.88/0.10, 0.14/0.71, and 0.99/0.95 for runoff volume, peak discharge, and time to peak, respectively, were obtained from the model.

The advent of the Internet has spawned the rapid development of web-enabled GIS tools. Moreover, it has greatly enhanced access to various real-time weather and hydrological data. Today, vast quantities of data can be managed with flexibility and speed. This development makes it technically feasible to greatly improve storm flood warning systems with a real-time simulation. This paper presents a prototype system with an application of Internet-GIS to a real-time flood prediction. The application integrates the spatial processing and analytical functionality of GIS systems, on-line real-time data, and a self-tuned hydrologic simulation engine into a new environment for decision support at an operational scale. The implemented system can be used to benefit emergency preparedness, transportation management, and natural resource management.

Watershed assessment requires techniques capable of synthesizing large quantities of spatial information. Fuzzy logic is one approach for addressing this problem. Geographic information systems (GIS) have the capacity to represent and integrate several levels of information on watershed characteristics and condition. Spatial analyses can show the relative condition of a watershed or delineate zones requiring different levels of protection related to a set of activities. One of the disadvantages of techniques commonly used in these analyses (e.g. Boolean, Weighted Index, Analytical Hierarchy Process) is that they do not include the uncertainty of a given factor or in the final results, which can be addressed with a fuzzy logic approach. With fuzzy logic a fuzzy membership function is defined for each environmental factor, which defines a region where the inclusion or exclusion of the factor is unclear. This paper briefly reviews the approach and application of fuzzy logic to the Riparian Restoration Ranking (R3) System on several montane watersheds in Arizona.

Lake Okeechobee is the second largest freshwater lake in the United States. It covers 1732 km² and is an important water source for the Everglades ecosystem and for meeting the diverse water needs of South Florida. However, during the last 25 years eutrophication processes in the lake have accelerated due in part to large quantities of non-point source nutrient inputs from predominantly agricultural land uses. The major nutrient of concern is phosphorus, primarily generated from intensive beef cattle and dairy farming activities located in tributary basins north of the lake. In 1989, a regulatory permitting program was implemented by the South Florida Water Management District to monitor total phosphorus concentrations in runoff from land use activities surrounding the lake. As a result of this regulatory program off-site discharge total phosphorus concentration limitations of 0.18 mg/L to 1.20 mg/L were developed for application on all non dairy land uses in the lake's northern tributary basins. More than 700 permits have been issued since the inception of this regulatory program. Water quality monitoring is conducted on each permitted parcel for a minimum of one year after issuance of the permit to determine compliance with the established total phosphorus concentration limitations.

The Roaring Fork & Fryingpan Rivers Multi-Objective Planning Project is a comprehensive Watershed Planning study completed from 1998 to 1999 under the direction of the Colorado Water Conservation Board to create better tools for management of the Roaring Fork River watershed located in Western Colorado. This project consolidated existing and new data on the Roaring Fork River and its major tributary, the Fryingpan River, into one large Geographic Information System (GIS) database for comprehensive analysis of the watershed as a whole. Current aerial photography, historic aerial photography, satellite imagery and USGS information were all used to develop valley-wide base mapping of the watershed. GIS is a generic term referring to computer programs used to enter, manage, analyze, and display geographic or mappable information in a coordinate system. The power of GIS lies in the ability to derive problem-solving information from existing data through such techniques as map overlays and modeling. GIS can store this information in an organized and consistent form. The advantage of GIS electronic master planning is the ability to update and revise the database as new information becomes available. The end products of successful GIS projects are high-quality cartographic maps and accurate, usable geographic databases. They are a powerful, cost-effective tool for undertaking difficult spatial analysis projects, and afford many advantages over traditional mapping methods. The true power of GIS lies in its analytical capabilities - the ability to produce new decision-making information through an analysis of existing data.

This paper presents a detailed study of the impact of remote sensing resolution on hydrologic parameterization for stormwater runoff estimation in a highly developed urban area. Three different remotely sensed images were used and a very high resolution GIS database was developed. GIS was used as a tool to perform spatial analysis. The watershed rainfall-runoff simulation was modeled using the kinematic wave approach in HEC-1, with the regional design storms as inputs. The remote sensing derived impervious area, SCS runoff curve number and flow resistance factor for overland flow planes in each sub-watershed were analyzed. Next, the simulated stormwater runoff estimates were compared in detail. The results show that, in such a variable and highly developed urban area, the simulated stormwater runoff peak flow using the high resolution RS data, NS001, could be 50% to 80% different from the values estimated by Landsat TM and SPOT data. The simulated runoff volumes could be 40% to 55% different.

Adverse impacts of human activities on water quality are usually due to the cumulative effect of several different land uses and management practices. However, cumulative effects are often difficult to detect within a reasonable time frame and monitoring budget because of the high natural variability in the systems of interest. One partial remedy for this problem is the use of predictor variables, which are defined as hydrologic measurements related to the water quality variable of interest. Such predictive variables can help model or explain some of the natural variability and thereby facilitate the detection of change. The paired-watershed approach, implemented statistically via linear regression, can detect smaller changes than a single-watershed approach when there is a strong correlation between the variable of interest and a predictor variable. Since many monitoring studies have a poor likelihood of detecting a cumulative effect, the statistical power of detecting change should bean important consideration.

Development of rehabilitation plans for watershed dams requires re-analysis of the upstream watershed using current hydrologic and hydraulic design criteria, and current stage-storage information. The Natural Resources Conservation Service software, SITES, developed with the assistance of the Agricultural Research Service and Kansas State University, has recently been upgraded to analyze watersheds containing multiple reservoirs within a modern, windows-based, Integrated Development Environment. A beta test version of this software is scheduled to be released for public use in the spring of 2000, and the final version is anticipated to be available in 2001. The environment consists of a full graphical user interface for the SITES software, with extensive help to guide the user through the data entry and to assist in interpretation of output. The environment allows the user to interactively compare and contrast design alternatives. SITES is the successor to the SCS DAMS2 program that was used in the original design of many of these dams, and a utility is being developed to assist in the conversion of old data sets to the current format. Among other features, the modern version of the software is capable of developing auxiliary spillway ratings based on vegetal retardance, and analyzing the potential for spillway breach at design flows. This report reviews key features of SITES and provides an overview of its application to watersheds with multiple flood control dams using the Integrated Development Environment.

Rivers and streams reflect the impacts and effects of human activities and natural perturbations that take place on the watershed. The response time for the river to react for the changes taking place within its watershed boundaries can vary anywhere from days to decades or longer. Removal of bank vegetation will accelerate the bank erosion, an immediate impact on the river. However, impacts of land use changes on the watershed may or may not be noticeable within the river for many years, if any. This paper will concentrate on a case study of the Kankakee River having a drainage area of 13,377 square km and covering parts of two Midwestern states. The drainage area of the river is split in half between the states of Illinois and Indiana. The river essentially flows on a flat terrain with very little topographical features. Most of the basin is used for agriculture. Some of the geologic, hydrologic, and hydraulic features of the basin that are playing a major role in the formulation and implementation of management decisions will form the basis of this paper.

Idaho has recently promulgated rules requiring the conjunctive management of ground water and surface water resources in areas designated as "Areas Having a Common Ground Water Supply." How many areas the state will eventually designate, and the size, location and makeup of these areas will depend on the numerous criteria (e.g., social, political, economic, management, hydrological, land use, and water use needs). However, these areas should be hydrologically competent; optimally sized and shaped to meet specific management needs and/or goals; and be acceptable to the state, water managers, water users, and the public. The purpose of this paper is to provide an overview of Idaho's criteria for delineating Areas Having a Common Ground Water Supply in Idaho and to recommend additional factors that should be considered during the delineation process.

Recent studies suggest that channel instability and aquatic ecosystem degradation occur at low levels of watershed imperviousness in humid regions of the U.S. In an effort to provide a more process-based explanation of observed thresholds of aquatic ecosystem degradation in urbanizing areas, U.S. Geological Survey (USGS) gauging data and simple hydrologic techniques were used to examine likely increases in discharge associated with varying levels of watershed imperviousness. The probable increases in these flow parameters for an annual flooding event were compared with analyses of a data set describing 270 stable and unstable channels from diverse geographic regions. Results suggest that a 10 – 20% increase in watershed imperviousness can result in a level of specific stream power that exceeds that corresponding to a high risk of instability for streams poised near a geomorphic threshold. Although risk of channel instability may be associated with different levels of watershed imperviousness, factors such as specific stream power relative to sediment caliber and channel entrenchment provide a more direct assessment of channel sensitivity to urbanization. Linking potential increases in specific stream power with the risk of channel instability establishes a more process-based connection between imperviousness and observed thresholds of aquatic ecosystem degradation.

In many watersheds, land use changes and hydraulic modifications have directly resulted in accelerated geomorphic activity and excessive sedimentation. Channel adjustment by erosion can be expected to occur if specific stream power exceeds a threshold of critical stream power. Excess stream power in stable meandering channels may result in a variety of responses that potentially range from extreme widening and braiding to extreme incision. Such extensive changes in channel pattern and morphology usually result in significant degradation of water quality and ecological integrity. An energy-based index grounded in geomorphic threshold theory was developed to improve the prediction of channel response to land use changes and hydraulic modifications. A very large and geographically diverse data set consisting of stable meandering rivers, braided rivers, and severely incised rivers was used in conjunction with logistic regression analysis to develop a probabilistic approach to predicting thresholds of channel instability in meandering channels. Simple variables such as slope, median bed material size, 2-year discharge, and drainage area are used as independent variables to estimate the risk associated with varying levels of excess specific stream power relative to sedimentary characteristics. Results indicate that simple indices of specific stream power derived from data that are readily available for most areas can provide accurate predication of thresholds of channel instability at the regional scale. This approach facilitates rapid identification of channels that are at highest risk of severe morphologic change due to an imposed increase in stream power and most sensitive to changes in the controlling variables. The approach provides tools for improved management of stream ecosystems through regional risk assessment, land use planning, and prioritization of stream and watershed management efforts.

Channel modifications during the 1960s have resulted in watershed instability in the Yalobusha River Basin, Mississippi. A comprehensive analysis of the watershed was conducted to provide a basis for design of diverse watershed rehabilitation practices. Proposed actions range from instream grade control to upland best management practices. Results of the analyses demonstrate a coupled geomorphic-hydraulic engineering approach can be utilized.

The first examples of active watershed management were largely designed to achieve economic objectives. These examples have left a legacy of impacts from denuded slopes and eroded soils to channelized and simplified streams. As a result there is an unspoken paradigm in watershed management that "mother nature knows best" and that natural systems provide more aquatic values than managed systems. Yet the legacy of impacts will take from decades to centuries to restore through passive processes, a delay that society is probably unwilling to accept. Instead, active watershed management can be used to accelerate this process. In fact, active management is essential in order to achieve the multiple resource values, both environmental and economic, provided by watersheds. To achieve these resources values, we must select a set of conditions rather than any single state. Examples of active management are provided. These include creation of off-channel habitat, placement of large woody debris (LWD) in streams, re-establishment of woody riparian vegetation and shade along streams, active road restoration efforts, and control of exotic species.

Stream restoration, the practice of modifying streams to improve geomorphic stability and ecological functionality, is now being applied to streams in Maryland. Many streams in Maryland have been degraded and destabilized due to urbanization impacts despite mandatory stormwater management regulations. Streams in some older neighborhoods have completed a cycle of degradation and are now achieving a state of "urban stream stability" and recovering biological habitat. Watershed characteristics that promote urban stability and recovery are identified and discussed. Review of the watershed characteristics can help identify if restoration efforts on a particular stream might be successful or if a stream has reached a "point of no return" at which restoration efforts will meet with little success.

In July 1997, Brevard County's Stormwater Utility Program installed a new type of trash and sedimentation control device called a continuous deflection separation (CDS) unit. This was the first American installation to use CDS Technology which was developed in Australia. After installation, autosamplers sere placed upstream and downstream of the CDS Unit and a year's duration of sampling data have been collected Monitoring has shown that the CDS unit has provided an average 52% removal efficiency for total suspended solids and 31% removal efficiency for phosphorus.

A method is developed for determining the direction and magnitude of channel width and depth adjustments. It could be used in sediment models that simulate scour and deposition. The method is based on quantification of extremal theories such as extremal energy dissipation, extremal sediment efficiency and extremal friction factor. The extremal method is combined with a variational approach to supply the width and depth adjustments. When the width and depth are the only degrees of freedom, two modes of channel adjustment toward equilibrium are predicted; width widening and bed rising on one hand, and width narrowing and bed lowering on the other hand. Therefore, the interrelationship between adjustments in width and depth of alluvial channels toward equilibrium is accounted for correctly. Predictions of channel width at the Yellow River are presented.

Metropolitan Atlanta's rapid growth in has been associated with widespread degradation of local terrestrial and aquatic habitats and water quality. Development of the sloping landscape and highly erodible soils of the Atlanta Piedmont geologic region has resulted in the discharge of significantly increased rates and volumes of surface rainfall-runoff and pollutant loads to local water bodies. Local impacts associated with this urban runoff include: increased erosion and sediment deposition; increased summer stream water temperatures; physical degradation of stream channels and riparian buffer zones; loss of in-stream biota, fisheries, and wildlife, violations of human health and ecological water quality standards; decreased aesthetics from litter, turbidity, and odor; flooding; impairments of downstream uses, including for drinking water, navigation, and recreation; and economic losses. An interdisciplinary scientific panel was convened to assess the conditions of Atlanta's streams and to identify those watershed management actions with the greatest potential to improve water quality, riparian and stream habitat in the Atlanta region. Broad recommendations included a description of elements to incorporate into a watershed management program for Atlanta, and specific suggestions for demonstration projects. The demonstration sub-watersheds collectively reflect the gradient of impervious cover and stream quality present in Atlanta, and represent conditions commonly observed throughout the area. The general recommendations for these areas should be applicable to other areas in the Country.

Channel bed degradation and the consequent failure of stream banks can be major contributors to the sediment budget of some watershed systems. In disturbed landscapes such as those found in Northern Mississippi, USA, sediment originating from channel bed and banks has been found to increase the total sediment yield considerably. Under these conditions, the assessment of erosion and sedimentation processes may be obtained from the use of a fully dynamic, physically based channel evolution model. The computational simulation software system CCHE1D provides sophisticated one-dimensional channel network flow and sediment transport models that can be used as a complement to a watershed-scale study. This GIS-integrated system was designed to provide more accurate and reliable estimation of sediment loads and morphologic changes in channel networks. It can be applied to the prediction of long-term erosion and deposition patterns, or used as a tool for the evaluation of the effectiveness of erosion control and channel remediation measures.

Following a comprehensive evaluation of environmental conditions in the Sierra Nevada in the mid-1990s, several watershed management strategies have begun that seek to improve water quality and aquatic habitat. Although these different approaches by federal agencies, state agencies, local jurisdictions, and citizens groups are proceeding independently, these various efforts may converge in part and should ultimately improve conditions in the streams of the Sierra Nevada. This paper explores the potential of watershed management in the highlands of California.

Overlaying traditional political boundaries upon natural watersheds creates institutional complexity due to the necessity of facilitating appropriate and effective linkages for watershed planning, analysis, and management. This paper describes and compares two urban watershed case studies designed to identify and illuminate their institutional complexities and various solutions over the past decade. Our premise is that the establishment and maintenance of effective institutional arrangements across political boundaries is an essential element for the overall success of watershed planning and management. Of special note is the relative role of the federal courts in both cases as well as the institutional lessons to be learned. The first case focuses upon the Rouge River Watershed near Detroit, Michigan. The Rouge River National Wet Weather Demonstration Project, begun in 1992, assists the forty-eight units of government in the seven sub-watersheds to develop more efficient means to control both point and nonpoint pollutants. As a result, the Michigan Department of Environmental Quality developed a new and innovative voluntary General Permit for storm water that is designed in part to facilitate effective watershed planning and management. Since the U.S. EPA recently stated that those commited to full compliance with all provisions of the Michigan General Storm Water Permit will satisfy the requirements of the new federal Phase II Storm Water rules and regulation, this model may be of interest elsewhere. The western watershed case study focuses upon the Tualatin River Basin near Portland, Oregon. In 1988, the Oregon Department of Environmental Quality established Total Maximum Daily Loads (TMDLs) for total phosphorous and ammonia for the Tualatin River. The river now meets its point source allocations but not its nonpoint ones. Despite significant progress in river quality and community involvement, some conflict remains over interpretations and expectations of science and the law. A variety of institutional arrangements have played important roles and continue to evolve. This examination is particularly interesting since the TMDLs in the Tualatin River were the first ones done by Oregon and among the earliest completed in the country.

In 1994 the Southwest Florida Water Management District (the District) initiated a Comprehensive Watershed Management (CWM) program that employs a watershed-wide approach to water resource management. Staff from a variety of disciplines, agencies and citizen groups make up "watershed teams" that have been assigned to eleven primary watersheds within SWFWMD. The teams are charged with 1) identifying and prioritizing issues relating to Areas of Responsibility: water quality, flood protection, water supply and natural systems; 2) developing remedial or protective actions to address water resource issues; and 3) implementing and monitoring those actions. The interaction of these factors has created a variety of potential environmental issues identified by the watershed teams. Developing and implementing remedial plans has been a formidable and lengthy process including the involvement of numerous stakeholders to achieve consensus. Clearly, without the "pbuy in" from these stakeholders, any lasting solutions are unlikely. The development of this process is the first step in a long-term change in the way the District will manage critical regional water resources in the future.

The Neuse River Basin encompasses 6,192 square miles in 19 counties and contains roughly one-sixth of the state's population. It is the third largest river basin in North Carolina and is one of only three major river basins whose boundaries are located entirely within the state. Water quality has been an issue in the Neuse River Basin for over a century. In 1887, legislation was passed to "prevent the throwing of dead stock into the waters of the Neuse River and its tributaries." The State Stream Sanitation Act of 1951 required a statewide survey of all surface waters. As a result of this legislation, the state completed the Neuse River Basin Survey Report in 1959. The most notable findings were the poor quality of waters downstream of wastewater dischargers. Coliform bacteria measurements of millions of organisms per 100 milliliters were not uncommon. The average dissolved oxygen concentration at the Neuse River downstream of Walnut Creek was as low as 3.7 milligrams per liter. Over 260 sites were sampled during 1955 and 1956 and a large number of these were unacceptable by today's standards.

The City of Rockledge is located in Brevard County along Florida's "Space Coast" near the Kennedy Space Center. The City has been developing and implementing a Stormwater Management Program using a watershed-wide management approach with the technical support of Camp Dresser & McKee, Inc. (CDM) since 1989. A phased approach was outlined to maximize City resources and to minimize incremental program costs while achieving defined benefits in a systematic manner to solve priority problems. The City of Rockledge prioritized problematic areas to create or expand regional wet detention facilities to solve existing flooding problems while retrofitting the entire 10 square mile upstream area to meet and exceed State water quality requirements to the Indian River and the St. Johns River. The City has proactively chosen these high levels of service for water quality to reduce existing nonpoint source pollutant loads to these receiving waters in advance of the upcoming State Total Maximum Daily Load (TMDL) and Pollution Load Reduction Goal (PLRG) programs. The City also desired to expand its park system as solutions were implemented. The City of Rockledge has worked to develop public-private partnerships with adjacent municipalities. State agencies. Federal agencies, landowners, developers, and borrow pit operators. This has allowed them to more quickly implement a proactive water quantity and water quality management program and save nearly one-half of the capital costs to-date. This has allowed the City to increase its Level of Service for stormwater management to its citizens in a very cost-effective manner.

Calculating direct event run off from rainfall by the Curve Number method relies on the coefficient Curve Number" (or "CN"), for which handbooks are the customary source. However, with the availability of large data sets and electronic data processing, local CNs can be calculated using local rainfall-runoff data. In this study a large data set was used to develop a better understanding of the land use variable as it applies to the Curve Number method of modeling storm runoff. Data-derived CNs for 15 distinct land uses were calculated using event rainfall-runoff data from 177 small watersheds in the United States. Many of the land uses were agricultural in nature, and all were as defined in The National Engineering Handbook-Section 4, Hydrology (NEH-4). Curve Numbers for each land use on each watershed were calculated using the Asymptotic method and evaluated at 3 scales; local, regional and national. Significant differences (5% level) were found between the CNs of almost all the different land uses tested. Differences in land use CNs at the local level can be attributed solely to a change in hydrological response of a watershed due to the land use because all other input variables of the Curve Number model (soil type, watershed condition and cover density) remain constant. Differences in land use Curve Numbers at the regional and national scale may be due to other factors in addition to land use, such as climate. Significant differences in CN were also found on grazed and ungrazed paired watersheds, and on watersheds that had undergone land use conversions. The general magnitudes and rank order of the average land use CNs were in rough accord with expected handbook values. Meadow land use almost always produced the lowest CN at both the local and regional level while Forest land use produced the lowest overall average Curve Number at the national level, but also displayed the highest CN variability. When comparable. Curve Numbers from desert brush land use was always higher than from all other land uses. No significant differences could be determined between Curve Numbers for pasture and range at the regional scale or between row crops and small grain land use at any scale. Where comparable, pastures usually had higher CNs than meadows.

In situ field calibration procedures were performed to determine the application depth and uniformity of irrigation systems used for applying lagoon effluent from swine farms. Calibration procedures were used on 52 irrigation systems including stationary sprinkler, traveling gun, and center pivot irrigation systems. Systems evaluated were operated under the same conditions in which normal day to day irrigation events were conducted. Uniformity coefficients for center pivot and traveling gun systems were on average 20 % higher than for stationary systems. Traveling gun systems produced a mean coefficient of uniformity of 73. Stationary systems produced a mean coefficient of uniformity of 56. Common causes of poor performance were below recommended operating pressure and/or excessive sprinkler or travel lane spacing. Observed wetted diameters on gun type sprinklers were approximately 10 % less than wetted diameters reported in manufacturer specification literature.

Recent research has shown the Inland Bays watershed has an excess of poultry manure for the cropland available. Agriculture is the largest land use in the Inland Bays and the largest source of nitrogen input into the Bays. Conservation tillage is one of the most widely used BMPs in the Inland Bays. Since erosion losses and direct surface runoff by overland flow are low in the Inland Bays watershed, nutrient management type BMPs need to be emphasized. Some of the important nutrient management BMPs include setting realistic yield goals, only applying enough nutrients to meet the crops needs, timing of application, manure analysis and calibration of manure spreaders. Alternative uses of poultry manure besides applying it to cropland must be found. Some of the potential alternative uses include using it as a fuel, as a feed for beef cattle, and using it in the horticulture industry after composting. If poultry manure was pelletized it would make it easier to handle and provide greater opportunities for alternative uses. Besides making an added value product out of the poultry manure other methods to reduce phosphorus transport include alteration of the feed to reduce the amount of phosphorus in the manure and adding alum.

In 1996, the Bioresources Engineering Department at the University of Delaware began to test a weed wiper unit. The weed wiper used the concept to wipe targeted growing woody vegetation with herbicides, leaving low growing vegetation to maintain stability on the horizontal and slope areas of the drainage ditches. Since that time three different wiper designs have been tested. A 20:1 glyphosphate Arsenal mix is effective to control sweetgum, cherry, tulip, popular, sumac, oak, birch, devils walking stick and maple at a rate of 1.85 to 2.77 L/ha. Early summer to late fall applications are most effective. The estimates cost for using a 20:1 mixture of glyphosphate to Arsenal mix at an application rate of 1.85L/ha is $84/ha. This is cheaper than broadcast spraying or mowing.

Major water resource issues including the tri-state water battle between Georgia, Alabama and Florida to salt water intrusion problems along the Georgia and South Carolina coast are affecting water resources availability for agricultural irrigation. Drought has also caused a more rapid implementation of management options for improving the efficiency of water use and understanding of water resource limits. Agricultural irrigation is essential to maintaining production and the economic viability of rural Georgia while minimizing risk.

Consistent with EPA guidance, meaningful and well timed public involvement is the cornerstone of a successful watershed management process and should result in better supported, more cost effective and expeditiously implemented total maximum daily loads (TMDLs). A stakeholder and decision support process has been implemented on the Truckee River in order to develop a revised TMDL to identify potential load reduction scenarios and to develop a pollutant load trading program. This paper discusses the development of the decision support process and system, including implementation of stakeholder participation and governance issues.

The Orphan Sites Feasibility Study is a trading initiative focused on providing incentives for entities to clean up "orphan sites"in exchange for some type of credit. To test the concepts developed as part of this study, a pilot project in the Clear Creek basin has been identified. This demonstration project, which includes the clean-up of a waste rock tailings pile is being used to evaluate various aspects of the trading framework. The evaluation focuses on specific areas such as environmental liability, access issues, brokering, and other lessons learned throughout the demonstration process. The results of the evaluation are the focus of this paper.

Since 1997, the Big Dry Creek Watershed Association has been working to scientifically assess conditions in the Big Dry Creek watershed. The Association has worked diligently to serve as a forum where a variety of perspectives can be expressed and considered as watershed concerns and issues are explored. The mission of the Association is "to develop a sound scientific understanding of water quality, flow, aquatic life and habitat conditions in the Big Dry Creek watershed for the purposes of 1) environmentally responsible decision-making with regard to land and stream uses and 2) identifying measures to improve and protect stream conditions." The Big Dry Creek Partnership, which includes the Cities of Broomfield, Northglenn and Westminster and Rocky Flats Environmental Technology Site (Rocky Flats), founded the Watershed Association and operates as a steering committee for the Association. These four entities discharge wastewater into Big Dry Creek and have been heavily involved in monitoring stream conditions for many years. The Association has been funded by contributions from the steering committee parties and several grants from the US Environmental Protection Agency (EPA) and the Colorado Water Quality Control Division (CWQCD). In addition to the steering committee, EPA and CWQCD, other participants include the City of Thornton, Natural Resources Conservation Service (NRCS), Colorado Division of Wildlife, Denver Regional Council of Governments, local ditch companies, farmers, and other watershed residents. In addition to stakeholder development, key activities completed by the Association over the last few years include collection of biological, chemical and physical data and integrated analysis of these data. The remainder of this paper focuses on the monitoring and data analysis approach used in the Big Dry Creek Watershed to form a sound scientific basis for prioritizing future activities in the watershed.

Local governments and federal agencies are pursuing increasing numbers of projects aimed at providing environmental restoration benefits. In planning these projects decision makers must make difficult choices involving the appropriate level of investment in restoration. Case studies are presented that describe the planning setting and decision support for environmental restoration investments in California and Wyoming. The author participated in planning and economic analysis for these studies under contract to the U.S. Army Corps of Engineers.

Rural watersheds in Arizona are currently facing serious challenges due to explosive and unprecedented population growth. Often, existing water resources are not adequate to balance the needs of a growing region while preserving natural resources. The Arizona Department of Water Resource (ADWR) has recently tried to focus attention on the problems and issues these areas face by creating the Arizona Rural Watershed Initiative (ARWI), a program to encourage regional partnerships through state funding. Rural entities by themselves rarely have the resources to address their problems. By working proactively within a watershed partnership, rural areas can more effectively address and obtain funding for regional solutions to water quantity and quality issues. Several of these partnerships have already coalesced, with several more groups in the formative stages. Partnerships include local stakeholders as well as representatives of resource and regulatory agencies active in the area who have agreed to cooperate in addressing watershed issues. In FY2000, the Arizona Legislature appropriated $1.2 million for the ARWI to help watershed partnerships identify water resources and develop regional watershed management plans. More than $3 Million in additional federal, state, local, and private funds has also been secured due to partnership contributions and activities. These funds will enable partnerships to develop watershed management plans and identify feasible projects and funding sources in order to protect their community, economic potential, quality of life, and natural resources.

Watershed-based trading is an innovative way for water quality agencies and community stakeholders to develop common-sense, cost-effective solutions to water quality problems in their watershed. It is a flexible alternative that allows the communities within a watershed to grow and prosper while retaining a common commitment to water quality. Communities, industries, and regulatory agencies around the country have shown great interest in watershed-based trading recently, as an innovative approach to achieve water quality benefits in a more cost-effective manner than traditional approaches allow. Even with all the interest, actual implementation of trading programs has been largely missing. The EPA Draft Framework for Watershed-Based Trading provides a strong overview of the trading concept, but potential trading partners need more hands-on guidance to transform this concept into a viable, working trading program.

A close partnership between researchers, resources agencies, and community groups allows for the most effective ecological and economic approach to environmental protection and watershed management. One of the better documented examples of this type of cooperative effort comes from the Tahoe basin (CA-NV) where studies over the past four decades have shown that many factors including, land disturbance, habitat destruction, air pollution, soil erosion, roads, have interacted to degrade the Basin's air quality, terrestrial landscape, and streams, as well as the lake itself. For effective lake management, we need to know (1) what are the specific sources of sediment and nutrients to the lake and what are their respective contributions, (2) how much of a reduction in loading is necessary to achieve the desired lake condition (lake response), and (3) how will this reduction be achieved? In this paper we present examples of ongoing research and monitoring which are proving extremely useful in watershed management. Topics include: changes in lake clarity and the importance of long-term data; response of lake phytoplankton to nutrients and a initial budget for nitrogen and phosphorus; paleolimnological reconstruction of baseline conditions and ecosystem response to anthropogenic disturbance; a clarity model to assess lake response to management; and a sediment transport model to evaluate nonpoint source loading. Only be providing a fully integrated watershed approach can we hope to develop effective restoration/mitigation efforts so essential to providing future generations with a quality environment in the Tahoe basin.

The Colorado River, which has its headwaters as far north as Wyoming, discharges into the Gulf of California in Mexico. The Colorado River basin includes about 638,953 square kilometers (246,700 square miles) in the United States. The Colorado River basin is divided into upper and lower basins at Lee Ferry, Arizona. The lower basin includes parts of Arizona, California, Nevada, New Mexico, and Utah. The Colorado River is the principal source of water for irrigation and domestic use in Arizona, southern California, and southern Nevada. Within this area, accounting for the use and distribution of water from the lower Colorado River is required by the U.S. Supreme Court Decree of 1964 (Supreme Court Decree) in Arizona v. California. In addition to its other requirements, the Supreme Court Decree directs the Secretary of the Interior (Secretary) to provide detailed and accurate records of diversions, return flows, and consumptive use of water diverted from the mainstream "stated separately as to each diverter from the mainstream, each point of diversion, and each of the States of Arizona, California, and Nevada." These records are provided annually by The Bureau of Reclamation (Reclamation) in a report entitled, "Compilation of Records in Accordance with Article V of the Decree of the Supreme Court of the United States in Arizona v. California Dated March 9, 1964".

In the 1980s, the U.S. Geologic Service, in cooperation with the U.S. Bureau of Reclamation, developed a water balance approach for estimating water consumption along the Lower Colorado River. Major estimated water consumption components were evaporation (E) and evapotranspiration (ET). These values were combined with a water balance applied to each of the four reaches of the river defined by the major dams, between Hoover Dam and the border with Mexico. The method is called the Lower Colorado River Accounting System (LCRAS). In 1990, Reclamation assumed responsibility for continued development of LCRAS and developed a strategy for improving the system. The strategy involved improving the accuracy of flow measurement, use of higher resolution remotely sensed digital satellite data, and improving the accuracy of E and ET estimates. In 1998, monthly evaporation coefficients were developed for use with reference ET from AZMET and CIMIS micro-meteorological weather stations. Surface water temperatures were related to water temperatures measured below the dams creating the reservoirs. The Penman-Monteith (P-M) equation was used to estimate open water evaporation taking into account the advection of heat energy in the water inflows and outflows for each reach. The temperature of water leaving Hoover Dam is nearly constant year round ranging from 10 to 13 C. Average water temperatures increase in each of the four reaches until approaching mean air temperatures in the last of the four reaches below Imperial Dam.

Severe drought conditions occurred in Texas during the 1990's and resulted in many water entities being forced to implement rationing programs to balance water demand with available supplies. Subsequently, the 75^th Texas Legislature mandated a review of the State's Water Plan. As irrigation is the largest user of water in the Texas Panhandle, a critical assessment of irrigation water demand estimates was needed. Previously, the Texas Water Department Board (TWDB) had provided these projections, principally through surveys from county and regional Natural Resource Conservation Service (NRCS) personnel. To attain a more localized focus, the state was divided into 16 regions. Each region was charged to review the TWDB estimates, and either accept their statistics or formulate a methodology that would possibly be more realistic in reflecting the irrigation water demands in their region. The Texas Panhandle High Plains area was designated as Region A. It was comprised of the following 21 counties: Armstrong, Carson, Childress, Collingsworth, Dallam, Donley, Gray, Hall, Hansford, Hartley, Hemphill, Hutchinson, Lipscomb, Moore, Ochiltree, Oldham, Potter, Randall, Roberts, Sherman and Wheeler.

In 1998, the Food and Agriculture Organization of the United Nations (FAO) published FAO Irrigation and Drainage Paper No. 56, a revision of the earlier and widely used Paper No. 24 for calculating evapotranspiration (ET) and crop water requirements. The revision uses a single method, the FAO Penman-Monteith equation, for calculating reference evapotranspiration (ET_o). In addition to the "mean" crop coefficient (K_c) values of FAO-24, FAO-56 provides tables of "basal" crop coefficients that represent ET under conditions having a dry soil surface. Associated equations for predicting evaporation from bare soil associated with crop transpiration are based on a water balance of the soil surface layer. Comparisons of daily ET from three agricultural crops are made between lysimeter measured ET and the basal K_c method of FAO-56 and the time-based basal K_c procedure of Wright (1982). Standard errors of estimate and accuracies were similar between the two methods and averaged about 0.77 mm/day or 15%.

The ASCE Evapotranspiration in Irrigation and Hydrology Committee (ASCE-ET) is recommending, for the intended purpose of establishing uniform evapotranspiration (ET) estimates and transferable crop coefficients, two Standardized Reference Evapotranspiration Surfaces: (1) a short crop (similar to grass) and (2) a tall crop (similar to alfalfa), and one Standardized Reference Evapotranspiration Equation. The standardized equation is derived from the ASCE-Penman Monteith equation, by simplifying several terms within that equation. The standardized equation, with appropriate constants provided in an accompanying table, is used to calculate evapotranspiration for the standardized short reference (ET_os) and/or evapotranspiration for the standardized tall reference (ET_rs). One constant is in the numerator and one is in the denominator. The constant in the right-hand side of the numerator (C_n) is a function of the time step and aerodynamic resistance (i.e., reference type). The constant in the denominator (C_d) is a function of the time step, bulk surface resistance, and aerodynamic resistance (the latter two terms vary with reference to type, time step, and daytime/nighttime).

The USDA ARS Walnut Gulch Experimental Watershed (WGEW) has been the site for numerous interdisciplinary experiments focused on the use of remote sensing for estimating distributed evaporation (E). This report documents a selection of the remote sensing techniques that have been applied at WGEW and reports the resulting accuracies of estimates of E, along with the advantages and disadvantages of each technique. This selected techniques were contrasted with an operational remote sensing approach for monitoring E implemented by the Bureau of Reclamation for the Lower Colorado River Basin.

The Imperial Irrigation District (IID) is located in the southeastern desert area of southern California. It is the largest irrigation district in the United States, importing over 85,000 cubic meters (3 million-acre feet) annually of Colorado River Water to irrigate 227,300 hectares (500,000 acres) of farmland. The IID has an extensive irrigation delivery system consisting of 2,575 kilometers (1,600 miles) of lined and unlined canals and an equally extensive drainage system comprised of 2,335 kilometers (1,450 miles) of open surface drains. The uniqueness of the irrigation district is that it provides year-round irrigation delivery and drainage services to its agricultural customers. The IID's infrastructure system is extensive, consisting of 1,930 kilometers (1,200 miles) of concrete lined canals, 182 kilometers (113 miles) of pipelines, 750 irrigation and drainage pumps, and over 15,000 associated canal and drainage structures consisting of checks, deliveries, siphons, bridges and spillways. Replacement and maintenance of this extensive infrastructure can be a challenge under the conditions of a year-round water delivery system. Irrigation canal outages for either construction or maintenance activities are permitted for only 3 and 5 day periods, depending on the complexity of the planned work. These short duration water outages are the maximum time allowed to avoid crop damage from lack of water. Drainage canals on the other hand have no ability for water outages due to the extensive and continual inflow of subsurface (tile) drainage system discharges. Work associated with construction and/or maintenance activities within drainage channels must be done while working around this constant flow condition. Because of the year-round delivery of water IID has had to be adaptive, developing unique and innovative methods to perform its construction and maintenance activities. This paper will overview how the IID addressed these "working-in-the-wet" issues in the construction of three recently installed projects.

Two major supply canals, namely the All American Canal and its Coachella Canal transport Colorado River water into the Imperial and Coachella valleys, respectively. This water is principally used for irrigation of farmland on about 463,000 acres in Imperial Valley, and some 60,000 acres in the Coachella Valley. In both valleys, agricultural production is a major year-round business activity. Hence, neither of these two supply canals can be taken out of service for extended periods for maintenance, repair, and/or modernization. Considered significant elements of the recently negotiated Key Terms for Quantification Settlement and California's Colorado River Water Use Plan (a plan under preparation), portions of these two major supply canals are planned to be concrete-lined. This will reduce a substantial portion of the seepage losses that are now occurring saving approximately 94,000 acre-feet per year. This paper will discuss current planning regarding the alternatives to carry out the concrete lining work without imposing any restrictions on day-to-day water delivery requirements.

The Salt River Project (SRP) is the nation's third-largest public power utility, Arizona's largest water supplier and the oldest multi-purpose reclamation enterprise in the United States. Rapid, large scale urbanization of the SRP water service area is necessitating significant changes in operations and maintenance. This paper discusses SRP's current and future approaches to maintenance in the wet. Topics include canal maintenance, weed control, standardized bulkhead units, canal dredging, brushing for algae removal and designs for floating platforms from which to perform a variety of types of canal maintenance with minimal impact on water delivery or canal bank recreation.

SRP delivers a million acre ft (1200 million cubic meters) of water annually to 250,000 acres (100,000 ha) in central Arizona through approximately 130 miles (210 km) of canals and 1200 miles (1930 km) of laterals. Water usage in the SRP system has shifted from primarily agricultural use to use as a drinking water source. Environmental regulations prohibit the use of most chemical herbicides. SRP has used white amur (Ctenopharyngodon idella) to control extensive aquatic weed growth in most of the canal system for ten years and has found them to be environmentally friendly and cost effective. Environmental regulations require the fish be sterile (triploid) and be physically contained within the canal system to avoid migration into natural rivers and streams. To qualify as a closed system, the canal system has been modified to include electric and physical fish barriers. Methods have been developed to economically and safely move the fish to different reaches of the system for maintenance purposes or to relocate fish that have moved downstream. Weed growth and fish population are monitored and fish are moved to maintain effective weed control throughout the system. The fish grow to as large as 4 feet (>1m) long and 50 lbs (22 kg), and have a life expectancy of 15 years. White amur are stocked at a rate of 35 fish per surface acre and are restocked at approximately 20% per year. Fish losses occur due to injuries caused by relocation activities, angling, and occasional chemical contamination. The use of white amur limits the use of chemical algaecides for taste and odor control. White amur have been shown to adequately control aquatic weed growth. SRP continues to expand reaches stocked with fish and to improve safety and efficiency of fish management.

Salinity in irrigation water withdrawn from the South Platte River in northeastern Colorado is impacting agriculture in the region. This study utilizes existing data to characterize the spatial and temporal changes in salinity within the river and to begin to identify the major sources of dissolved solids in the middle reaches of the South Platte River. A complete characterization of salinity and its sources in the basin is a necessary first step in identifying effective management and control strategies. Results of this study indicate that large jumps in electrical conductivity (EC) and dissolved solids load occur in some upstream segments of the study area, while in other segments the changes are much more gradual. The three major tributaries are major contributors to both the EC levels and dissolved solids load of the main stem. Municipal wastewater treatment plants are also shown to be a potentially significant source of dissolved solids load at downstream monitoring stations.

Implementing the land retirement option as presented by the San Joaquin Valley Drainage Implementation Program (SJVDP) and the Central Valley Project Improvement Act (CVPIA) is not without some expense in converting lands to other uses and managing water, soil, land, and wildlife resources to minimize adverse effects and maximize beneficial effects. Herein we describe the potential consequences of the implementation of land retirement upon the hydrologic system, upon the quality of land from a biologic perspective and a pedologic perspective, and upon the economic system. The results described are based on computer modeling studies. Studies of this type have inherent limitations based on modeling assumptions, availability of data for modeling verification, and the accuracy of model predictions of natural phenomena. For the modeling studies described in this report, little baseline data was available for model verification. Therefore, modeling results must be carefully reviewed and interpreted based on modeling assumptions. In the absence of retired land monitoring data, the results of the modeling studies provided the best framework for Committee deliberations on the environmental and economic consequences of implementation of land retirement programs.

Irrigation generally is defined as the application of water to soil for the purpose of supplying the moisture essential for plant growth. On the whole it has been highly successful. More than one third of the world's total harvest has been produced on irrigated land which amounts to only about 17 percent of the world's crop land. A common consequence of irrigation in semi-arid regions of the world is the potential development of soil salinity and/or water logging. Pure water is lost through evapotranspiration (ET) and the salts become concentrated in the soil solution. Irrigation water that is applied in excess of ET percolates and transports the excess salts below the root zone. Depending upon the geologic and hydrologic system water tables rise and can reach the root zone. If the water table gets too high an artificial drainage system must be installed to remove water and dissolved chemical constituents from the root zone.

Reuse of saline-sodic drainage water is an important management option in areas of the western San Joaquin Valley affected by shallow ground water. A number of scientific investigations, computer simulations and on-farm research projects involving drainage water reuse have been conducted over the past twenty years. Several strategies have been proposed, tested and found successful over a number of years. Particular emphasis is placed on the need to control soil salination, avoid adverse effects on soil physical properties, and to select potential crops that are suitable for reuse systems. Trace elements such as boron, selenium and molybdenum may also influence the feasibility of using saline-sodic drainage water for irrigation.

Agricultural lands of the westside of the San Joaquin Valley in California are underlain by a low permeability clay layer causing a shallow water table to rise toward the soil surface. The soils and shallow groundwater contain naturally occurring trace elements. High concentrations of trace elements, such as selenium, pose a potential hazard to fish and wildlife. About 400,000 hectares of lands have shallow groundwater within 3 m from ground surface. Tile drains have been installed in approximately 50,000 hectares of affected lands to lower the water table and remove the salts from plant root zone. The Valley consists of the San Joaquin River Basin in the north and the Tulare Lake Basin, a closed basin, in the south. Drainage management measures have been developed and implemented to control salinity, shallow water table, and trace elements. Innovative drainage management practices implemented, in the San Joaquin River Basin and the Tulare Lake Basin, to protect the fish and wildlife from toxic trace elements in drainage water are discussed.

Wetlands have shown promise as a stormwater best management practice (BMP). Current recommendations suggest wetland surface areas be at least 1% of the contributing watershed area to ensure significant water quality improvement. Most urban areas are severely limited with regard to available land areas for wetland creation, thus, to be practical, smaller wetland:watershed area ratios will be necessary in many locations. A one ha (2.4 acre), in-stream constructed wetland was built to intercept drainage waters from approximately 240 hectares (600 acres) of agricultural and urban watershed, which resulted in a wetland:watershed area ratio of 0.004:1. The wetland was instrumented to monitor hydrology and chemistry. Monitoring began in early 1996 and continued through December of 1999. Water quality samples were analyzed for total kjeldahl nitrogen (TKN), ammonium-nitrogen (NH₄-N), nitrate-nitrogen (NO₃-N), total phosphorus (TP), and ortho-phosphorous (OP). Over the monitoring period, NO₃-N concentrations were reduced by +60% NH₄-N by +30%, and TKN by 9.5%. Total and ortho-phosphorous levels in increased 55%. Yearly and seasonal means indicate that significant improvements in NO₃-N and NH₄-N concentrations can be achieved with relatively small wetlands.

The purpose of the Brawley Constructed Wetlands Demonstration Project is to study how wetlands can improve the quality of agricultural drain water, New River stream flows and, ultimately, inflows to the Salton Sea. To achieve this end, two demonstration wetlands are proposed for construction in Imperial County near Brawley, California: the 7-acre Brawley Site and the 68-acre Imperial Site. These sites will serve to demonstrate the effectiveness of using constructed wetlands through a 3-year monitoring program to treat constituents of concern in the water column, sediment, and biota. Healthy freshwater habitats are at a premium in the Imperial Valley. Creation of additional wetland habitats has long been desired. The goal of these constructed wetlands is to provide wetland habitat while removing sediment, nutrients and contaminants such as DDE and selenium that currently are degrading the New and Alamo Rivers and the Salton Sea. In addition to nutrients, the biota of the Salton Sea is stressed by the slowly increasing salinity now at 44 parts per thousand (ppt), considerably higher than the 33 ppt of ocean water. Physical and biochemical processes within the wetlands are expected to reduce nutrient loads, pesticide/herbicide toxicity, and selenium concentrations, while increasing dissolved oxygen in the water returned to the New River, thus improving water quality for wildlife habitat and contributing toward the achievement of Regional Water Quality Control Board standards. There is evidence that wetlands can reduce the concentration of available selenium by rendering it insoluble. The slightly elevated levels of selenium in the New River and Imperial Valley drains may be reduced, further improving waterfowl habitat. Concern over the decline of the Salton Sea, the need to improve the quality of agricultural effluent, and the history and perception of pollutant flows from Mexico have led to the formation of the Citizens Congressional Task Force on the New River, which is responsible for the development of the Brawley Constructed Wetlands Demonstration Project.

The charge of the United States Bureau of Reclamation (Reclamation) from its creation was to provide water to agriculture to the arid western states. As such, Reclamation began construction of large-scale water storage and delivery systems throughout the west. While drainage was an integral part of these irrigation systems, little thought was taken for the condition of the water drained from the land, nor its impact on the receiving stream. Now, in an era of greater environmental awareness and concern, the impact of agricultural waste waters on receiving streams has gained more, and more attention. As the primary steward of the nations waters, state governments have been required to take inventory of the rivers flowing through their states and assess and report the water quality of each. Additionally, the states have been required to develop plans for the improvement of the quality of water bodies not meeting water quality use standards through a process termed TMDL. The TMDL, or Total Maximum Daily Load, process is intended to define water pollution constituents of concern, and develop plans for the improvement of the quality of the state's waters. Part of the process is to look at the contribution of agricultural waste waters on the overall quality of the receiving streams. Reclamation has assisted the state of Idaho in the TMDL process for the Boise and Payette rivers. Options, ranging from water reuse to full-scale wetlands treatment systems, for the reduction of agricultural loading to these rivers were developed and presented as a partial solution.

This study performs a parametric sensitivity analysis of FWETMOD, a computer model to simulate wetland hydrology as well as the corresponding total suspended solids and pollutant concentrations. FWETMOD evolved out of the Virginia Field Scale Wetland model (VAFSWM), and can be used to analyze the design parameters relevant to hydrologic and water quality aspects of stormwater-driven wetlands. In the present study, the input parameters of FWETMOD were analyzed and the more sensitive parameters were identified. The model was applied to a small wetland in West Lafayette, Indiana and the results are reported.

Cropping systems that include the sequential reuse of saline-sodic drainage waters could be a key component of irrigation sustainability along the Westside San Joaquin Valley in California. In this irrigated region, where there is no regional drainage outlet, such cropping systems could facilitate the installation of artificial drainage on 304,000 ha of lands with shallow water tables and reduce the volume of drainage water currently disposed in underground soil strata, or in evaporation ponds. The electrical conductivities of salinity of drainage waters on the Westside range from 6 to 20 dS/m, SARs range from 6 to 35, and the boron contents in 80 % of the drainage waters are less than 14 mg/L, with 50 % having less than 4 mg/L. Although these water quality characteristics limit the crops that can be grown, salt tolerant forages, trees, and shrubs provide options for sequential reuse. Sequential reuse of drainage water may eliminate the need for evaporation ponds by storing the remaining drainage water in soil strata beneath lands dedicated to the production of salt tolerant forages. A similar process occurs now beneath irrigated lands without artificial drainage, but on a much larger area. Alternatively, if fields receiving saline drainage water were artificially drained, the evaporation pond area needed could be decreased by at least a factor of five, or the capacity requirements of a regional drain reduced, if one were ever built.

Field properties — topography, hydraulic resistance, infiltration, and erodibility — play an important role in the performance of surface irrigation systems, and appropriate characterizations of these are required as data input to simulation or design software. A brief overview of descriptive formulas and approaches to determining their parameters is presented. Direct measurements are contrasted with indirect approaches deducing extant parameters from system behavior. A new ASCE Task Commitee on the subject is noted.

An analytical solution is obtained for the simplified transient stream-aquifer interaction problem using Fourier analysis and complex variables. The solutions obtained for small sinusoidal water level disturbances of different periods are used to identify a number of dimensionless parameter groups that influence the solution. The analytical solutions are compared to numerical solutions obtained using the MODFLOW model. The dimensionless parameter groups combining the canal, aquifer and sediment properties are used to understand how they affect the stream-aquifer interaction. The analytical solution is useful in verifying the accuracy of computer models simulating stream-aquifer interaction.

The WAVE model describes the transport and transformations of matter and energy in the soil, crop and vadose environment. A lateral field drainage subprogram was added to the WAVE model to simulate the lateral subsurface drainage flow. The subsurface drainage is considered as the drainage provided by evenly spaced parallel drains with a free outlet, either drain tubing or ditch. The rate of subsurface water movement into drain tubes or ditches depends on the hydraulic conductivity of the soil, the drain or ditch spacing, the hydraulic head in the drains, the profile depth and the water table elevation. Hooghoudt's steady state equation, as used by Hooghoudt (1940), was selected for incorporation in the WAVE model. The subsurface drainage subprogram was calibrated and validated by comparison with SWAP model (The Netherlands) and DRAINMOD (USA) using seven years of field data in The Netherlands, under fallow and cropped condition. It is concluded that the WAVE model, in comparison to the SWAP and DRAINMOD model, provides as good a prediction of the lateral subsurface drainage flow to drains.

Transpiration by mature- and sprout-forms of Emory oak (Quercus emoryi) was estimated by the sapflow velocity method on two adjacent sites, one unharvested and the other harvested for fuelwood, in the oak woodlands of southeastern Arizona. There were few differences in daily transpiration between mature trees on either site; however, there were differences in transpiration between the mature trees on the two sites and the post-harvesting stump sprouts on the harvested site. The importance of these differences is shown by translating the estimates of transpiration by individual trees to a stand-basis through extrapolations of the results to inventories of stocking conditions in the vicinity of the sites sampled. On a per-hectare basis, about 1,900 liters of water were transpired by mature Emory oak on the unharvested site, while 3,150 liters of water were transpired annually by the mature trees and post-harvesting stump sprouts. One factor contributing to the greater transpiration of Emory oak in the harvested stand is likely the occurrence of a large number of vigorous post-harvesting sprouts.

Contour basin irrigation layouts are used to irrigate rice and other cereal crops on heavy cracking soils in South East Australia. In the present study, a physically based two-dimensional simulation model that incorporates all the features of contour basin irrigation systems is developed. The model's governing equations are based on a zero-inertia approximation to the two-dimensional long wave equations of motion. The equations of motion are transformed into a single non-linear advection-diffusion equation in which the friction force is described by Manning's formula. The empirical Kostiakov equation and the quasi-analytical Parlange equation are used to model the infiltration process. The governing equations are solved by using a split-operator approach. The numerical procedure is capable of accommodating multiple interconnected basins as used in typical commercial layouts. The model was verified against field data collected on commercial lasered contour layouts.

An integrated measurement and modeling study was conducted to evaluate the effects of plot complexity and differences in soil hydrologic response on measuring and modeling infiltration and runoff processes. Experiments using a variable intensity rainfall simulator were conducted on a 2 m by 6 m soil box lysimeter packed with two soils with different infiltration capacities with two different plot configurations. Rainfall application rates varied between 50 and 200 mm/hr. Results of the rainfall simulator experiments found differences between the hydrologic responses of the two soils to changes in applied rainfall intensity. The study also showed that the location of the two soils relative to each other in the soil box did have an important effect on runoff response and that the response changed with changes in rainfall intensity. A distributed, process based hydrologic simulation model was used to model the complexity of the plots. The results of the simulation model showed the difficulty in accurately modeling the hydrologic response from heterogeneous soil plots.

This paper describes the programmatic evaluation approach being used by the U.S. Army Corps of Engineers (Corps) and a team of Federal agencies in preparation of environmental impact statements (EISs), which address the range of potential environmental and socioeconomic impacts for the future allocation of water resources within the Alabama-Coosa-Tallapoosa (ACT) and Apalachicola-Chattahoochee-Flint (ACF) River Basins. The programmatic approach includes hydrologic modeling to produce a range of flow conditions, which are anticipated to bracket the range of flow conditions that would result from any allocation of water resources. The environmental impacts for the modeled range of flows are then presented in the EISs, which will form a basis for decisions by the Federal Commissioner to the River Basin Compact Commissions on whether to proceed with implementation of allocation formulas currently being negotiated by the States of Alabama, Florida and Georgia. Implementation of the water allocation formula will likely include changes in reservoir operations and reallocations of reservoir storage in upstream reservoirs to provide for future water supply needs in the basins. Follow-on environmental assessments will also be prepared for implementation phase actions.

This paper describes a joint effort between the U.S. Army Corps of Engineers (Corps), numerous Federal cooperating agencies (e.g., U.S. Environmental Protection Agency and U.S. Fish and Wildlife Service, and various contractors) to assess the impacts of water allocation on the water quality and freshwater environmental aspects of the Alabama-Coosa-Tallapoosa (ACT) and Apalachicola-Chattahoochee-Flint (ACF) River Basins. Several numerical models, including the HEC-5 surface water quantity model, the BASINS, HEC-5Q, and CE-QUAL-W2 water quality models, and various biological evaluation tools are being used to assess mainstem riverine communities, mainstem riparian wetlands, reservoir fisheries, and protected species in a basinwide approach for these two large river basins. These analyses are being conducted to support preparation of the environmental impact statements (EISs) for each basin. Draft EISs for each basin were completed in September 1998, and preparation of Final EISs is awaiting the negotiation of the final allocation formulas by the States of Alabama, Florida, and Georgia.

The Municipal Authority of Westmoreland County (MAWC), a public water supply system licensed by the Pennsylvania Department of Environmental Protection (PADEP), obtains a large proportion of their untreated water from the Youghiogheny River. The operation of this system is currently regulated by Water Allocation Permits issued by PADEP that establish a maximum daily withdrawal based upon minimum acceptable flows which serve to ensure that water quality and low flow augmentation are not compromised. As a result of current and projected increases in potable water demand, and recent regional drought conditions, this water authority is exceeding the permitted withdrawal amounts. In order to prevent a continuation of these violations, PADEP directed the authority to secure suitable additional storage to provide the needed supplemental releases during periods of low flow / high demand. Since the U.S. Army Corps of Engineers' Youghiogheny River Lake is located upstream, the water purveyors contacted the Corps to explore the potential for reallocating storage to water supply. The opportunity for this reallocation may exist because recent improvements in water quality in the basin have resulted from the reduction in the area's heavy industry and mining. This loss of heavy industry, as well as a reduction in the severity of acid mine pollution, has reduced the pollution load of the Youghiogheny River. Consequently, the original authorized storage and release schedule for the Lake may be out-of-date because since less storage is probably needed to dilute pollution.

A major water and energy provider in Central Texas is the Lower Colorado River Authority (LCRA). It supplies water and electricity to over a million persons. Approximately 10 percent of that electricity is generated from hydroelectric power plants on the six dams in the Highland Lakes system on the lower Colorado River. A real-time scheduling system has been developed and is being implemented into the LCRA Energy Management System (EMS) to optimally schedule the hourly operation of thirteen hydropower generating units in concert with the three steam-electric power stations operated by the LCRA. The hydro scheduling system uses a mixed integer linear programming (MILP) model of the Highland Lakes to determine the optimal hydro generation based on forecasted power and water demands and hydrologic conditions over the next 72 hours. The MILP model maximizes hydropower generation while satisfying hourly and daily constraints on generation capacity, lake storage and flow releases. The solution to the scheduling model is provided in real-time to the EMS which uses the results to determine generation unit commitment in the LCRA power system.

Operation of a pumped storage system as dictated by the price of electricity and capacity limitation on other generating plants is considered. The formulation incorporates constraints on permissible fluctuation in the upper reservoir as demanded by the lake shore property owners and recreational needs, lower reservoir capacity, downstream channel capacity and flood stage consideration, in-stream flow needs, efficiency and capacity of the generating and pumping units, and storage release relations. The time dependent cost data clearly governs the operating policy of a pumped storage system. Several different cost patterns are considered to analyze variations in the solution. Because the pumped storage plant is part of a large system involving different types of generating units, the plant can be put into use when other plants can not sustain the load. However, the data pertaining to the whole system is hard to obtain. Thus the scenarios are analyzed by imposing various limits on the total production capacity. This permits an analysis of variations in actual operations that took place and the model recommended operations. The mathematical formulation results in a nonlinear integer program.

Colorado's Decision Support Systems (CDSS) consist of the decision support systems (DSS) for the Colorado and Rio Grande rivers. The Colorado River DSS (CRDSS) was developed first and resulted in the implementation of the HydroBase database for storing water resources data, as well as modeling tools. CRDSS focused on surface water modeling and administration. The Rio Grande DSS (RGDSS) is currently under development and introduces ground water data and modeling. This paper summarizes some of the main features of the CDSS related to planning and administration of water resources in Colorado, illustrating how the CDSS provides insight into water resources issues.

Resources degradation, population increase and urbanisation growth have made urban water supply system more and more complex to manage and develop. WATSIDE is a methodology that allow to analyse and tackle the complexity of this system, including stakeholders intervention, in order to make more consensual and holistic decisions. This methodology considers indeed the critical issues in an integrated way, so that relationships can be established between upstream and downstream investments, remedial treatment and preventative quality control and the interest of the separate parties. In this paper, an overview of the method is proposed and its application on a river basin in France is developed and discussed.

The main purpose of this paper is to develop the monthly operating rules for the multi reservoirs such as Hwacheon, Soyanggang, and Chungju located at the upstream of the Han River Basin in Korea. The monthly operating rules by an implicit stochastic optimization and a regression analysis are developed. Since it is necessary to generate the inflows having the same statistical properties of historical data for applying an implicit stochastic optimization, the synthetic inflow data of three reservoirs are generated by periodic ARMA (1,1) model. And then an implicit stochastic optimization is applied to get optimal multi reservoir operating results. These results are used to derive operating rules by a regression analysis. The regression equations among the beginning storage, the synthetic inflow and the release are obtained. Using the graphical analysis of this operating rules, the applicability to the flood season and non-flood season is accomplished.

During the last few years, hydrometeorological monitoring, communications, and computer technology used in streamflow forecast systems have advanced rapidly. It is now possible to develop streamflow forecasting systems that operate on a standard personal computer. However, complex data collection, verification and processing issues still must be addressed to implement robust and useful systems. This paper presents recent case studies of streamflow forecasting technology applications and discusses some of the issues associated with implementing streamflow forecasting systems. Automated and user-controlled systems are discussed, as well as the use of forecast information in the water resources decision making process.

Flood control reservoir operations typically involve forecasts of reservoir inflows and uncontrolled tributary flows at points downstream of the dam. Since such forecasts often are accompanied by appreciable uncertainty, operators may be interested in the results of scenario, or "what if," analysis when reservoir operating rules allow for some discretion. One approach to scenario analysis is to determine an optimal release schedule for each flow scenario considered. While intuitively appealing, this approach may do little to help the operator select the particular schedule that must be implemented. A better approach is to determine a release schedule that optimally hedges against the identified contingencies. To this end, a two-stage decision model of the flood control operating problem is developed. It is assumed that flow data for the first stage are known with certainty, corresponding to a short-term forecast, while data for the second stage comprise the scenarios of interest, corresponding to probabilistic forecasts for periods further in the future. Scenario generation, objective function formulation, and computational issues are discussed.

We summarize the results of a survey to water managers in the western U.S. on the impacts specific climate change scenarios would have on their operations. We also consider (1) the specific adaptation strategies considered worthwhile by both water managers and researchers, and (2) the institutional constraints and other obstacles to adaptation. The six types of variability considered are (1) one-day extreme rainfall events, (2) seasonal extreme high or low snowfall, (3) extreme droughts, (4) extreme heat waves, (5) seasonality of spring runoff, and (6) seven-day low flow. The results provide insight into the adaptation strategies considered worthwhile and the institutional changes needed to minimize the impact of climate change and variability.

An ongoing program to transfer river forecasting technology used by the National Weather Service (NWS) to Mexico's Comisión Nacional del Agua (CNA) is presented. Implementation of the NWS River Forecast System (NWSRFS) requires both traditional techniques for data analysis and calibration as well as development of unique tools integrated with Geographic Information System (GIS) technology to deal with the sparse data network. A cooperative development approach to training was established to permit CNA engineers to gain experience in a broad array of elements of forecast system development and implementation as a foundation for ongoing system implementation and operation. To provide timely data for forecasting, a system was devised and is being implemented that allows regional data collection centers to promptly post observed data reports to a central database through a web-based data entry interface. Because NWSRFS is being implemented in river basins with international boundary water issues, CNA and NWS are coordinating the program with the US and Mexican Sections of the International Boundary and Water Commission (IBWC).

A state of the art rainfall and river forecasting system has been implemented by the ACP (Panama Canal Authority) to assist in daily operations of the Panama Canal. More accurate forecasts of precipitation, and inflows and elevations for the reservoirs that provide water for canal operations will help ensure an adequate water depth for the more than 13,000 ships that transit the canal each year. The project to design and install the system is the result of an agreement between the Panama Canal Commission and the U.S. National Oceanic and Atmospheric Administration's National Weather Service Office of Hydrology [NOAA NWS/OH] signed in August 1996. The National Weather Service and its contractors developed, implemented, and integrated the forecasting system for the Meteorological and Hydrographic Branch of the canal's Engineering Division. The work involved the integration of two distinct projects — the development of a mean areal precipitation reporting and forecasting system (PANMAP) linked with a streamflow and reservoir operation simulation and forecasting system (PANFCST). The Hydrologic Research Center, San Diego, California, developed the PANMAP system which uses radar, climate station measurements, and model forecasts to produce estimates of MAP (mean areal precipitation) over each of the nine sub-basins in the 1,289 square miles (333,851 ha) canal watershed. These precipitation values are then provided to the PANFCST system, implemented by RTi (Riverside Technology, inc.), Ft. Collins, Colorado. PANFCST computes simulations and forecasts of inflows to and pool elevations in the reservoirs that provide the water for canal operations. The NWS International Hydrologic Technology Transfer Center provided project management and coordinate integration activities.

The Huntington District, Corps of Engineers has responsibility for operating a variety of flood control projects in Ohio, Kentucky, West Virginia and Virginia. Recently, the Corps has recognized the need to provide flood-warning systems as independent systems or as components of flood control projects. The Huntington District has completed two systems and is currently involved with the implementation of two additional flood-warning systems within the District. These systems are located at Columbus, Ohio for the West Columbus Local Protection Project (LPP), Greenbrier River Basin located in West Virginia, Tug Fork River Basin located in West Virginia and Kentucky and Levisa Fork River Basin located in Kentucky and Virginia. The data acquisition requirements and the current status of these flood warning systems emphasizing the coordination involved in their implementation and design will be presented. All of these systems utilize existing data sources to the extent practicable and provide supplemental precipitation or stage data at key locations to the local communities. Most of these systems are intended to provide direct sources of flood warning data / information to local communities within the basins where structural flood control measures are not practical.

The phenomenon known as El Nino/Southern Oscillation (ENSO) has been identified as the single most prominent signal of interannual climate variability. A number of independent efforts have been made to investigate the relationships between ENSO and hydrologic variations. Especially interesting are some statistically significant relationships of ENSO with streamflows in Australia, South America, the Western United States and elsewhere. In such cases, the ENSO could be used as an indicator for long-term streamflow forecasting which would be invaluable to water resources planners and managers. Few studies, however, have addressed this water management issue associated with the ENSO. The primary objective of this paper is to incorporate the ENSO information into a reservoir operation model formulated with stochastic dynamic programming (SDP). In Korea, nobody has as yet investigated the potential ENSO impact on Korean streamflows although previous studies reported that statistical relationships between ENSO and precipitation exist in some basins in Korea. Therefore, the present paper first analyzes a streamflow pattern at a Korean gauging station, Chung-Ju dam, in relation to ENSO, using a statistical technique called composite analysis. This result is then used for deriving an optimal monthly operation rule for Chung-Ju reservoir to illustrate the benefit of employing ENSO information.

Accuracy of seasonal forecasts is improving due to recognition of large-scale climatic patterns. We discuss the need to identify the scope of the forecast and choose an appropriate presentation method for the forecast in order to successfully implement seasonal forecasts in operation. Probabilistic forecasts best represent the type of information contained in climate-based forecasts, and degrading them to deterministic forecasts can limit their effectiveness. Differences in climatic patterns have an impact on the accuracy of forecasts for different geographic regions that is demonstrated by the more accurate preliminary results for a river in the Pacific Northwest than one in the Colorado headwaters. We use non-parametric statistical methods to choose predictors from standard climate indices and sea-surface temperatures and forecasting streamflow.

Following serious problems with public water supply in England and Wales (E&W) in 1995/96, the British Government asked all water companies to develop drought contingency plans (DCP) and agree them, by March 2000, with the Environment Agency. The Environment Agency (referred to hereafter as the Agency) is the environmental regulator of the water industry in E&W with the task of ensuring the proper management of water resources. Local government is not directly involved in water resources in E&W. DCPs for public water supply are intended to ensure that measures are taken early enough in a drought to ensure that communities do not run out of water or do not experience serious restrictions in supply that could endanger public health. The Plans are designed to manage this risk, which changes constantly through a drought. The drought actions contained within the DCP are a trade-off between more frequent minor inconveniences for the public and the environment and potentially catastrophic impacts towards the end of a drought. Following the adoption in E&W of a national procedure for assessing the yield of a water resource system, the DCPs have added significance as they can impact the yield. Water resource management in E&W is changing from a "Predict and Provide" model of resource development to a "Plan, Manage and Monitor" model. This new approach places much greater emphasis on maximising the output from the current system of resources. The improvement in managing risk, as reflected in DCPs, is one area where improvement may be made and the yield increased. It is the area that is explored within this paper.

Criteria and guidelines for the design and evaluation of spillway structures vary from country to country as well as from state to state. In some countries, recent current guidelines allow for the design and evaluation of flood security measures for dams to be based on the risk associated with a catastrophic dam failure caused by an extreme flooding event. This is somewhat different from the traditional standards-based approach, which is generally utilized in the United States. For example, current State of Colorado dam safety criteria require that the flood security of existing dams is based on the hazard classification and the size of the structure. Design rainfall values for an existing large, high hazard dam typically range from the 0.5 Probable Maximum Precipitation (PMP) event to the full PMP event. However, an Incremental Damage Assessment (IDA) may be performed in order to determine the incremental damages associated with a potential dam failure during different magnitude flooding events. If incremental damages are small, a lower level of protection may be warranted.

The State of California created the Metropolitan Water District of Southern California in 1928 to provide supplemental water supplies to the rapidly developing urban areas of the coastal plain. Today, Metropolitan's service area encompasses virtually all of the Los Angeles and San Diego metropolitan regions, with a population of nearly 17 million. In total, annual water demands placed on all sources within Metropolitan's service area were approximately 3.8 million acre-feet in calendar year 1997. Water supplies for this 5,200-square-mile area come from an array of sources, including local surface and groundwater supplies, as well as the imported supplies from the City of Los Angeles' aqueduct system and Metropolitan's supplies from the Colorado River and Northern California. About 47 percent or 1.8 million acre-feet of the total demand was met from Metropolitan's supplies. In addition, aggressive local programs among Metropolitan's 27 member public water agencies and over 300 subagencies heavily promote groundwater conjunctive use programs, and reclamation programs for reuse of supplies. Approximately 1.6 million acre-feet of local demands are met by these two sources.

A comprehensive basin-wide sediment management assessment of Lake Solano in Northern California identified affordable solutions to operation and maintenance problems caused by sedimentation. The Solano County Water Agency (Agency or SCWA) sponsored studies in 1997 and 1998 to develop a sediment management program for Lake Solano, an 888,000 cubic meter (720 acre-feet) diversion reservoir supplying water to Sacramento Valley farms and municipalities via the Putah South Canal (Northwest Hydraulic Consultants, 1998). The reservoir and canal are part of the U.S. Bureau of Reclamation (USBR) "Solano Project" completed in 1958. (Figure 1) The Project includes Monticello Dam and Lake Berryessa, which provides 1.93 billion cubic meters (1.6 million acre feet) of water storage. The drainage basin for Lake Solano downstream of Monticello Dam is approximately 98 square kilometers (38 square miles) and is the primary source of sediment deposited in the lake. Since construction, approximately 191,000 cubic meters (250,000 cubic yards) of sediment have accumulated in Lake Solano, infilling approximately 20 percent of the reservoir's initial capacity. The sediment affects the operation of the water diversion system. The most significant problem is flow restriction through the trashrack at the canal headworks due to a combination of trashrack corrosion and accumulation of organic debris and sediment. There also were perceptions by Agency operating staff and municipal water customers that sediment deposits degrade water quality by increasing turbidity while promoting aquatic weed growth and algae blooms responsible for bad tastes and odors that require additional water treatment. The Agency initially believed extensive dredging would be required to restore the operating capacity of Lake Solano, reduce turbidity, and retard the growth of rooted aquatic plants. A comprehensive investigation was conducted for the Agency to develop methods for removing and managing sediment accumulations and for reducing the delivery of sediment from the watershed to the reservoir. The approach and results from that investigation are presented herein.