In 1991, the U.S. Congress established the U.S. Geological Survey (USGS) National Water- Quality Assessment (NAWQA) Program to develop long-term, nationally consistent information on the quality of the Nation's streams and groundwater. Congress recognized the critical need for this information to support scientifically sound management, regulatory, and policy decisions concerning the increasingly stressed water resources of the Nation.

The U.S. Geological Survey (USGS) established the National Water Quality Assesment (NAWQA) program in 1985 to assess water quality conditions and trends in representative river basins and aquifers across the United States. With this report, the NRC's Water Science and Technology Board has provided advice to USGS regarding NAWQA five separate times as the program evolved from an unfunded concept to a mature and nationally-recognized program in 2002. This report assesses the program's development and representative accomplishments to date and makes recommendations on opportunities to improve NAWQA as it begins its second decade of nationwide monitoring.

The first two decades of the U.S. Geological Survey's National Water Quality Assessment (NAWQA) Program have provided a successful and useful assessment of U.S. water-quality conditions, how they have changed over time, and how natural features and human activities have affected those conditions. Now, planning is underway for the third decade (Cycle 3) of the Program outlined in the Science Plan, with challenges including ensuring that the NAWQA remain a national program in the face of declining resources, balancing new activities against long-term studies, and maintaining focus amidst numerous and competing stakeholder demands. The Science Plan for Cycle 3 articulates a forward-thinking vision for NAWQA science over the next decade, building on the previous cycles' data, experience, and products. Preparing for the Third Decade (Cycle 3) of the National Water-Quality Assessment (NAWQA) Program explains the national needs outlined in the plan, NAWQA's need to emphasize collaboration with other USGS and external programs, other federal agencies, state and local governments, and the private sector.