In 1997, New York City adopted a mammoth watershed agreement to protect its drinking water and avoid filtration of its large upstate surface water supply. Shortly thereafter, the NRC began an analysis of the agreement's scientific validity. The resulting book finds New York City's watershed agreement to be a good template for proactive watershed management that, if properly implemented, will maintain high water quality. However, it cautions that the agreement is not a guarantee of permanent filtration avoidance because of changing regulations, uncertainties regarding pollution sources, advances in treatment technologies, and natural variations in watershed conditions. The book recommends that New York City place its highest priority on pathogenic microorganisms in the watershed and direct its resources toward improving methods for detecting pathogens, understanding pathogen transport and fate, and demonstrating that best management practices will remove pathogens. Other recommendations, which are broadly applicable to surface water supplies across the country, target buffer zones, stormwater management, water quality monitoring, and effluent trading.

Soil erosion has become a problem of crisis proportions in developing countries around the globe, and better approaches to land management are desperately needed. This book provides analytical frameworks to guide the creation and appraisal of soil erosion control programs. The authors discuss a broad range of important issues involved in designing and implementing more effective soil conservation programs. The book begins with a discussion of the physical and economic dimensions of soil erosion and an estimation of the extent of the problem. It then explains how to improve the evaluation of soil conservation programs by integrating scientific knowledge with economic methods and procedures. A series of practical illustrations graphically demonstrates the application of the concepts derived from the theory. The most important organizational, institutional, technical, and macroeconomic aspects of soil and land management appraisal are outlined, and the major elements of project or program design are also pinpointed and illustrated. Finally, the book suggests areas most in need of future research.