Download or read book Compendium of Watershed scale Models for TMDL Development written by and published by . This book was released on 1992 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Compendium of Tools for Watershed Assessment and Tmdl Development written by L. Shoemaker and published by . This book was released on 1997-11 with total page 227 pages. Available in PDF, EPUB and Kindle. Book excerpt: Broadens the review of models and techniques from solely watershed loading models to include receiving water models and ecological assess. techniques and models. It summarizes avail. techniques and models that assess and predict physical, chemical, and biol. conditions in waterbodies. Includes info. regarding: a wide range of watershed-scale loading models; field-scale loading models; receiving water models, including eutrophication/water quality models, toxics models, and hydrodynamic models; integrated modeling systems that, for example, link watershed-scale loading with receiving water processes; and ecological techniques and models that can be used to assess &/or predict the status of habitat, single species, or biol. community.

Download or read book Watershed Scale TMDL Model written by Charles Wayne Downer and published by . This book was released on 2007 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Assessing the TMDL Approach to Water Quality Management written by National Research Council and published by National Academies Press. This book was released on 2001-08-24 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the last 30 years, water quality management in the United States has been driven by the control of point sources of pollution and the use of effluent-based water quality standards. Under this paradigm, the quality of the nation's lakes, rivers, reservoirs, groundwater, and coastal waters has generally improved as wastewater treatment plants and industrial dischargers (point sources) have responded to regulations promulgated under authority of the 1972 Clean Water Act. These regulations have required dischargers to comply with effluent-based standards for criteria pollutants, as specified in National Pollutant Discharge Elimination System (NPDES) permits issued by the states and approved by the U.S. Environmental Protection Agency (EPA). Although successful, the NPDES program has not achieved the nation's water quality goals of "fishable and swimmable" waters largely because discharges from other unregulated nonpoint sources of pollution have not been as successfully controlled. Today, pollutants such as nutrients and sediment, which are often associated with nonpoint sources and were not considered criteria pollutants in the Clean Water Act, are jeopardizing water quality, as are habitat destruction, changes in flow regimes, and introduction of exotic species. This array of challenges has shifted the focus of water quality management from effluent-based to ambient- based water quality standards. Given the most recent lists of impaired waters submitted to EPA, there are about 21,000 polluted river segments, lakes, and estuaries making up over 300,000 river and shore miles and 5 million lake acres. The number of TMDLs required for these impaired waters is greater than 40,000. Under the 1992 EPA guidance or the terms of lawsuit settlements, most states are required to meet an 8- to 13-year deadline for completion of TMDLs. Budget requirements for the program are staggering as well, with most states claiming that they do not have the personnel and financial resources necessary to assess the condition of their waters, to list waters on 303d, and to develop TMDLs. A March 2000 report of the General Accounting Office (GAO) highlighted the pervasive lack of data at the state level available to set water quality standards, to determine what waters are impaired, and to develop TMDLs. This report represents the consensus opinion of the eight-member NRC committee assembled to complete this task. The committee met three times during a three-month period and heard the testimony of over 40 interested organizations and stakeholder groups. The NRC committee feels that the data and science have progressed sufficiently over the past 35 years to support the nation's return to ambient-based water quality management. Given reasonable expectations for data availability and the inevitable limits on our conceptual understanding of complex systems, statements about the science behind water quality management must be made with acknowledgment of uncertainties. This report explains that there are creative ways to accommodate this uncertainty while moving forward in addressing the nation's water quality challenges.

Download or read book Application of the Water Quality Management DecisionSupport System WQMDSS in an Illustrative WatershedManagement Study written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Development of total maximum daily loads (TMDLs) for critical pollutants in impaired watersheds is becoming a standard approach in environmental management. This requires the identification of future loading of contributing pollutants, and the development of a plan to allocate the necessary reductions among the point and nonpoint sources in the watershed to achieve this loading. To support water quality model-based TMDL development, US EPA has released the modeling framework BASINS-Better Assessment Science Integrating Point and Nonpoint Source, which incorporates several watershed water quality models within a GIS-based data management system. Current capabilities of BASINS enable simulation of watershed water quality associated with a TMDL, thus supporting TMDL development via a trial-and-error approach. The limitations of the trial-and-error approach are addressed via systematic search procedures implemented within the Water Quality Management Decision Support System (WQMDSS) that is designed to aid stakeholders and decision-makers efficiently identify TMDLs. The focus of the research presented in this paper is to demonstrate the applicability of WQMDSS in developing TMDLs for a realistic illustrative case study. Using the data for the Suwanee Creek Watershed in Georgia, which underwent a recent TMDL study, a series of illustrative scenarios are examined to consider varying target total suspended solids (TSS) loading rates, as well as different instream water quality parameters. The instream water quality is estimated using a calibrated HSPF model. Future land use development plans, with and without consideration of riparian buffer strips for nonpoint source control, to meet instream water quality goals are identified. Through this illustrative study, a range of uses of WQMDSS in watershed-scale TMDL development is demonstrated.

Download or read book Total Maximum Daily Load Analysis and Modeling written by American Society of Civil Engineers. TMDL Analysis and Modeling Task Committee and published by Asce American Society of Civil Engineers Ewri. This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report reviews more than 35 TMDL models and procedures for estimating the maximum amount of a pollutant that a water body can receive and still meet applicable water quality standards.

Download or read book Utility of Watershed Models written by Robert Nunoo and published by . This book was released on 2020 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt: Watershed models are used to represent the physical, chemical, and biological mechanisms that determine the fate and transport of pollutants in waterbodies (Daniel 2011). These models, in general, are used for exploratory, planning, and regulatory purposes (Harmel and others 2014). Watershed models have numerous applications; one such use is the development of total maximum daily load (TMDL). TMDL is the amount of pollution a waterbody can receive without becoming impaired. Because of the challenge of uncertainty associated with models and the TMDL development process, the United States Clean Water Act Section 303 (d)(1)(c) requires that a margin of safety (MOS) be specified to account for uncertainty in TMDLs. The question of how MOS is estimated in TMDL was identified as a problem by the National Research Council (NRC 2001). Since the identification of the problem about two decades ago, there have been very few inventories or audits of approved TMDL studies.This study describes a natural language processing and machine learning aided review of the MOS in approved TMDLs from 2002 to 2016. The study determined whether the MOS values incorporated followed a pattern and examined whether there exist a relationship between MOS values and some ecological conditions. Relatively few TMDLs were based on some form of calculation to estimate explicit MOS values; these TMDLs constituted only 16% of the reviewed sample. The remaining 84% used conventional values, but few of those studies provided reasons for their selected values. A statistical assessment of those MOS values revealed that the MOS depended on States (location of waterbody), USEPA regions, waterbody type, designated water use, TMDL model used, and dataavailability. The findings indicate that few TMDL developers are following the National Research Council’s suggestions of using a rigorous uncertainty estimation approach for rational choices for the MOS. An adaptive approach based on Bayes-Discrepancy was proposed for estimating an MOS for a TMDL. The approach is based on the Bayesian hierarchical framework of estimating uncertainty associated with watershed models. With this approach, TMDL developers can communicate the effects of their watershed model. The approach was applied to a Ferson Creek model of the Fox River watershed to access variability and uncertainty in the model results, and also estimate possible MOS values for two monitoring stations in the watershed. Results suggest that an MOS of 0.04 mg/L could lead to a 0.1 probability of violating the water quality standard for an underpredicting model. The Bayes-discrepancy estimation method will enable TMDL developers and watershed managers to strike a balance between implementation options and water quality concerns.

Download or read book Review of the New York City Watershed Protection Program written by National Academies of Sciences, Engineering, and Medicine and published by National Academies Press. This book was released on 2020-12-04 with total page 423 pages. Available in PDF, EPUB and Kindle. Book excerpt: New York City's municipal water supply system provides about 1 billion gallons of drinking water a day to over 8.5 million people in New York City and about 1 million people living in nearby Westchester, Putnam, Ulster, and Orange counties. The combined water supply system includes 19 reservoirs and three controlled lakes with a total storage capacity of approximately 580 billion gallons. The city's Watershed Protection Program is intended to maintain and enhance the high quality of these surface water sources. Review of the New York City Watershed Protection Program assesses the efficacy and future of New York City's watershed management activities. The report identifies program areas that may require future change or action, including continued efforts to address turbidity and responding to changes in reservoir water quality as a result of climate change.

Download or read book Protocol for Developing Pathogen TMDLs written by and published by . This book was released on 2001 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Watershed Models written by Vijay P. Singh and published by CRC Press. This book was released on 2010-09-28 with total page 678 pages. Available in PDF, EPUB and Kindle. Book excerpt: Watershed modeling is at the heart of modern hydrology, supplying rich information that is vital to addressing resource planning, environmental, and social problems. Even in light of this important role, many books relegate the subject to a single chapter while books devoted to modeling focus only on a specific area of application. Recognizing the

Download or read book Protocol for Developing Nutrient TMDLs written by and published by . This book was released on 1999 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Multi model Approach to Predicting Pathogen Indicator Bacteria Loading in Tmdl Analyses written by Donna-May G. Sakura-Lemessy and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation utilizes data from four sub-watersheds in the Little River Experimental Watershed, GA to develop models to improve forecast predictions related to the management of surface-water pollution due to non-point source runoff. Non-point source pollution is the primary cause of US surface-water quality impairment and a main transport mechanism for pathogens and other pollutants into receiving surface water bodies (US EPA 2008). In response to pollution reduction and watershed remediation mandates under the Federal Clean Water Act (1972)--particularly the Total Maximum Daily Load (TMDL) program--the role of water quality modeling in effectively rehabilitating impaired waters has taken on greater importance. Consequently, the significance of this study is that it is the first of its kind to incorporate a multi-model approach to address limitations in using single water quality models. In this regard, it builds on water quality engineering research by presenting methods to estimate contaminant concentrations and reduce uncertainty in overall model predictions in impaired water-bodies. Methodologically, the key point of departure in this dissertation is centered on the fact that water quality modeling is the cornerstone of TMDL analyses but the associated prediction uncertainty affects their adequacy in providing reliable contaminant loadings estimates in an impaired water body. As such, utilizing hydrological and water-quality process equations embedded in the two most widely used watershed-scale models, the Soil and Water Assessment Tool (SWAT) and Hydrological Simulation Program-Fortran (HSPF), and observed data from the sub-watersheds mentioned above, the dissertation addresses this limitation by combining results from the two competing models to reduce uncertainty and enhance accuracy of predictions. The study was conducted in two phases. First, HSPF and SWAT--two extensively-used, scientifically-rigorous, US EPA-approved watershed-scale codes--were used to build models of the four study catchments. The models were individually calibrated and shown (based on Nash-Sutcliffe Efficiency (NSE) ratios) to produce reliable simulations of the hydrologic and water quality conditions in the watershed. The second phase of the analysis involved using a multi-model approach to combine model forecasts. Model combination, introduced by Bates and Granger in 1969, has emerged as a viable analytical technique (Claesken and Hjort, 2008; Ajami et al., 2006) and widely-used across disciplines to improve model-forecasting results (Kim et al., 2006; Shamseldin et al., 1997; Granger, 2001; Clemens, 1989; Thompson, 1976; Newbold and Granger, 1974; Dickinson, 1973). After calibration, the model predictions were combined for each catchment using three different methods: the Weighted Average Method (WAM), the Nash-Sutcliffe Efficiency Maximization Method (NSE-max) and an Artificial Neural Network Method (ANN). Comparison of the results of the multi-model formulation with original individual model results showed improved estimates with all three combination methods. The improvement in model accuracy (based on NSE ratios) varied from modest to significant in both hydrologic and water quality variables. These improvements were attributed to a reduction in model structural uncertainty resulting from the ability to capture aspects of some of the more complex watershed interactions from exogenous information provided by the contributing models. It should be noted here, however, that as model availability increases, if additional models (beyond those utilized here) are used with this approach, care should be taken to ensure the credibility of each individual model for simulating the watershed scale processes under review. Limitations of this study include possible bias introduced by the use of deterministic models to estimate probabilistic contaminant distributions, limitations in available data, and the use of a seven-year study period that did not account for possible impacts of shorter periods of extreme hydrologic conditions on the individual model performances and model combination weightings. Recommendations for future research include (a) improving watershed-scale codes to better describe the probability distribution functions characteristic of contaminant distributions and data collection on wildlife species and populations; and investigating the fate and transport processes of pathogenic indicator bacteria deposited in forested areas and the impact of extreme hydrologic conditions on model performance and weighting. Overall, the findings from this dissertation suggest that water quality modeling incorporating a multi-model approach has the potential to significantly improve predictions compared to the predictions obtained when only one model is used. Clearly, the findings reported here have significant implications in improving TMDL analyses and remediation plans by presenting an approach that exploits the strengths of two of the most complete and well-accepted watershed-scale water quality models in the United States. Moreover, the findings of this dissertation auger well for the future of TMDL management in that it provides a more robust and cost effective basis for policy makers to decide on effective management strategies that incorporate acceptable risk, allowable loading and land use.

Download or read book Total Maximum Daily Load Development and Implementation written by Environmental and Water Resources Institute (U.S.). Total Maximum Daily Load Analysis and Modeling Task Committee and published by . This book was released on 2021-11 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "MOP 150 provides detailed descriptions of several watershed and receiving water quality models used in total maximum daily load (TMDL) analysis and modeling, highlighting recent advancements in TMDL development and implementation"--

Download or read book Modeling Onsite Wastewater Systems at the Watershed Scale written by John McCray and published by IWA Publishing. This book was released on 2009-09-13 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this User’s Guide is to provide guidance on modeling watershed-scale problems associated with decentralized wastewater-treatment systems (DWTS), with a particular focus on onsite wastewater systems (OWS). The guide focuses on modeling transport and fate of the nutrients nitrogen (N) and phosphorus (P) because these are the most common OWS constituents of concern, and because these pollutants are regulated in surface waters (N and P) and in ground water (N). However, limited but useful information is also provided regarding the modeling of organic wastewater contaminants, such as pharmaceuticals, pesticides, and other household products. It provides some general information on modeling bacterial pollutants. The guide can be used by decision makers to determine whether relatively simple screening models (presented in Appendix A) are sufficient for use in the decision-making process, or if sophisticated models (presented in Appendix B) are more appropriate. The document provides guidance about the type of model that should be used for particular scenarios, and the data requirements for model implementation. The guide is also useful to modeling experts by providing guidance on important issues such as conceptual-model development, mathematical-model selection, modelsensitivity analyses, model uniqueness, and calibration. Finally, the guide provides some real-world and hypothetical case studies that can demonstrate the usefulness of using watershed-scale models, and provide templates for certain common scenarios relevant to the decentralized wastewater treatment community.

Download or read book Water Quality Modeling for Wasteload Allocations and TMDLs written by Wu-Seng Lung and published by John Wiley & Sons. This book was released on 2001-04-30 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt: Complete, practical coverage of pollution control regulations and water quality modeling Water Quality Modeling for Wasteload Allocations and TMDLs provides practical guidance for engineers charged with determining the volume and character of wastewater that a body of water can receive without suffering environmental damage. Following the discussion on water pollution control regulations and their relationships to water quality modeling and wasteload allocation for determining the total maximum daily load (TMDL), the first half of the book focuses on quantifying the model coefficients to characterize physical, chemical, and biological processes of a variety of water quality problems. The remainder of the book guides engineers in the application of EPA-developed models for regulatory use. Presenting numerous case studies and a substantial amount of data, this comprehensive guide: * Covers practical applications of wasteload allocation * Provides guidance to develop technical information for obtaining National Pollution Discharge Elimination System (NPDES) permits * Demonstrates the application of STREAM, QUAL2E, WASP, and HAR03 Water Quality Modeling for Wasteload Allocations and TMDLs is an essential resource for state and federal water quality agencies, consulting engineering firms, publicly owned treatment works, environmental biologists and chemists, and public health officials involved with pollution control.

Download or read book Swrrb a watershed scale model for soil and water resources management written by J.G. Arnold And J.R. Williams and published by . This book was released on 1994 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Urban Stormwater Management in the United States written by National Research Council and published by National Academies Press. This book was released on 2009-03-17 with total page 611 pages. Available in PDF, EPUB and Kindle. Book excerpt: The rapid conversion of land to urban and suburban areas has profoundly altered how water flows during and following storm events, putting higher volumes of water and more pollutants into the nation's rivers, lakes, and estuaries. These changes have degraded water quality and habitat in virtually every urban stream system. The Clean Water Act regulatory framework for addressing sewage and industrial wastes is not well suited to the more difficult problem of stormwater discharges. This book calls for an entirely new permitting structure that would put authority and accountability for stormwater discharges at the municipal level. A number of additional actions, such as conserving natural areas, reducing hard surface cover (e.g., roads and parking lots), and retrofitting urban areas with features that hold and treat stormwater, are recommended.