Water quality degradation from agricultural production and other non-point sources is of great concern in the United States. Watershed management is generally recognized as the most practical and efficient way to improve water quality and other environmental indicators while maintaining regional economic viability (National Research Council 1999). Watershed management is a decision making process that integrates biophysical sciences, socioeconomic information, and local knowledge. It has a collaborative problem-solving planning and management orientation and emphasizes influential and voluntary participation of multiple local and nongovernmental interests (Born and Genskow 2001). A watershed is a geographic area in which water, sediment, and dissolved materials drain to a common outlet – a point on a larger stream, a lake, an underlying aquifer, an estuary, or an ocean (USEPA 1993). Watersheds are a logical way to divide landscapes and are ultimately the most appropriate analytical and management units for water quality improvement. Individual watersheds are the most ideal geographical units for identifying holistic cause-and-effect water quality relationships, linking upstream uses to downstream effects, developing reasonable water cleanup plans, targeting limited resources, and educating and involving the public (Water Environmental Federation 1992). For every natural watershed there is also a “shadow” watershed defined by human and natural features that extend the decision maker’s interest beyond the physical boundaries of a watershed. As shown in Figure 6.1, integrated watershed management (IWM) reconciles political, economic, and social conditions (“shadow watershed”) with ecological and biophysical aspects (“physical watershed”). It incorporates plans, policies, and activities to control water and related resources and processes in a given watershed (National Research Council 1999). The integrated watershed management approach has become a social movement for solving water and related natural resource problems in the United States and worldwide. For example, 1,500 locally-led watershed initiatives have been established in the United States, most of them during the 1990s (Lant 1999). Similar observations can be made for other countries, such as Canada, European Union, Australia, and Brazil.