The U.S. Environmental Protection Agency (EPA) was introduced on December 2, 1970 by President Richard Nixon. The agency is charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress. The EPA's struggle to protect health and the environment is seen through each of its official publications. These publications outline new policies, detail problems with enforcing laws, document the need for new legislation, and describe new tactics to use to solve these issues. This collection of publications ranges from historic documents to reports released in the new millennium, and features works like: Bicycle for a Better Environment, Health Effects of Increasing Sulfur Oxides Emissions Draft, and Women and Environmental Health.

Development and initial testing of a mathematical model to continuously simulate pollutant contributions to stream channels from nonpoint sources is presented. The Nonpoint Source Pollutant Loading (NPS) Model is comprised of subprograms to represent the hydrologic response of a watershed, including snow accumulation and melt, and the processes of pollutant accumulation, generation, and washoff from the land surface. The simulation of nonpoint pollutants from both pervious and impervious areas is based on sediment as a pollutant indicator. The calculated sediment washoff is multiplied by user-specified `potency factors' that indicate the pollutant strength of the sediment for each pollutant simulated. Both urban and rural areas can be simulated. Initial testing of the NPS Model was performed on three urban watersheds in Durham, North Carolina; Madison, Wisconsin; and Seattle, Washington. The hydrologic simulation results were good while the simulation of nonpoint pollutants was fair to good. Sediment, BOD, and SS were the major pollutants investigated. A detailed user manual is provided to assist potential users in application of the NPS Model. Parameter definitions and guidelines for parameter evaluation and calibration are included. Possible uses of the NPS Model for evaluation of nonpoint pollution problems are discussed.

Nonpoint-source pollution (NPSP) poses a special challenge to society's ability to manage its collective environmental good - especially surface and groundwater quality. Since there is no `point', such as an outfall pipe, from which the pollution is being discharged and can be measured, pollution can reach the ambient environment without being monitored. Since management of air and water polution requires the definition and enforcement of limits on discharges or the imposition of fees on those discharges, inability to measure limits our ability to manage this environmental problem. This book presents a state-of-the-art review and discussion of economists' efforts to resolve this major problem and attempts to provide a way of working around it. The book sets forth the theoretical issues, modeling, and the actual programs set up to confront this issue.

This volume contains most of the scientific contributions to the workshop ``Prediction of Agricultural Nonpoint Source Pollution: Model Selection and Application'' held in Venice, in the historic Ca' Vendramin Calergi, in June, 1984. Other contributions of specialists who were not able to attend the workshop have also been included in an attempt to make the work more complete. It is hoped that this collection will be useful to planners who operate in the field of agricultural diffuse source pollution, since several contributions are state-of-the-art presentations and others are specialized studies by American and European researcher.

Non-point source (NPS) pollution causes widespread impairment to surface water in the United States and can potentially impact human health and safety. Nutrient NPS pollution from agriculture is one of the most damaging and widespread non-point source problems in surface water.

The last few years have witnessed an enormous interest in application of GIS in hydrology and water resources. This is partly evidenced by organization of sev eral national and international symposia or conferences under the sponsorship of various professional organizations. This increased interest is, in a large measure, in response to growing public sensitivity to environmental quality and management. The GIS technology has the ability to capture, store, manipulate, analyze, and visualize the diverse sets of geo-referenced data. On the other hand, hydrology is inherently spatial and distributed hydrologic models have large data requirements. The integration of hydrology and GIS is therefore quite natural. The integration involves three major components: (1) spatial data construction, (2) integration of spatial model layers, and (3) GIS and model interface. GIS can assist in design, calibration, modification and comparison of models. This integration is spreading worldwide and is expected to accelerate in the foreseeable future. Substantial op portunities exist in integration of GIS and hydrology. We believe there are enough challenges in use of GIS for conceptualizing and modeling complex hydrologic processes and for globalization of hydrology. The motivation for this book grew out of the desire to provide under one cover a range of applications of GIS tech nology in hydrology. It is hoped that the book will stimulate others to write more comprehensive texts on this subject of growing importance.