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.

A guide for urban areas to achieve sustainability by recovering water, energy, and solids Integrated Sustainable Urban Water, Energy, and Solids Management presents an integrated and sustainable system of urban water, used (waste) water, and waste solids management that would save and protect water quality, recover energy and other resources from used water and waste solids including plastics, and minimize or eliminate the need for landfills. The author—a noted expert on the topic—explains how to accomplish sustainability with drainage infrastructures connected to receiving waters that protect or mimic nature and are resilient to natural and anthropogenic stresses, including extreme events. The book shows how to reduce emissions of greenhouse gasses to net zero level through water conservation, recycling, and generating blue and green energy from waste by emerging emission free technologies while simultaneously installing solar power on houses and wind power in communities. Water conservation and stormwater capture can provide good water quality for diverse applications from natural and reclaimed water to blue and green energy and other resources for use by present and future generations. This important book: Considers municipal solid waste as an ongoing source of energy and resources that will eliminate the need for landfills and can be processed along with used water Presents an integrated approach to urban sustainability Offers an approach for reducing greenhouse gas emissions by communities to net zero Written for students, urban planners, managers, and waste management professionals, Integrated Sustainable Urban Water, Energy, and Solids Management is a must-have guide for achieving sustainable integrated water, energy, and resource recovery in urban areas.

Quantitative models are crucial to almost every area of ecosystem science. They provide a logical structure that guides and informs empirical observations of ecosystem processes. They play a particularly crucial role in synthesizing and integrating our understanding of the immense diversity of ecosystem structure and function. Increasingly, models are being called on to predict the effects of human actions on natural ecosystems. Despite the widespread use of models, there exists intense debate within the field over a wide range of practical and philosophical issues pertaining to quantitative modeling. This book--which grew out of a gathering of leading experts at the ninth Cary Conference--explores those issues. The book opens with an overview of the status and role of modeling in ecosystem science, including perspectives on the long-running debate over the appropriate level of complexity in models. This is followed by eight chapters that address the critical issue of evaluating ecosystem models, including methods of addressing uncertainty. Next come several case studies of the role of models in environmental policy and management. A section on the future of modeling in ecosystem science focuses on increasing the use of modeling in undergraduate education and the modeling skills of professionals within the field. The benefits and limitations of predictive (versus observational) models are also considered in detail. Written by stellar contributors, this book grants access to the state of the art and science of ecosystem modeling.

This new volume explores important recent approaches and advanced techniques for the effective management and treatment of wastewater. The book provides a range of diverse techniques for achieving optimum water quality management, for restoration of water bodies, for the improvement of a circular water economy, and for effective water reuse. Many of the new methods and technologies included in the book focus on sustainable phytoremediation techniques, such as the use of earthworms, ecological floating beds, and anaerobic biovalorization. The book also comprehensively discusses the scope of nanomaterials for wastewater treatment. Some of the least explored aspects of water quality improvement, such as use of eco-roofs, the role of remote sensing in water quality management, and biosand filters for household wastewater treatment, are discussed as well.