This is a practical, extensively documented guidebook on the assessment and control of nonpoint source pollution from agricultural, urban, construction, and forested areas, and on the health of aquatic ecosystems and human use of water resources. It covers atmospheric deposition as a mode of transport for nonpoint and point source pollutants that include eroded sediments, nutrients, heavy metals, organic and inorganic chemicals, chlorides, and microorganisms. The book presents examples and references that highlight past and present successes and failures and give guidance for decision-makers and technical staff in designing site-specific solutions to local nonpoint source pollution problems.