Throughout U.S. history, the Nation has made major investments in assessing natural resources, such as soils, minerals, and hydrocarbons. The maintenance and the improvement of water quality has been one of the major areas of public investment and government regulation. One of the contributions the U.S. Geological Survey proposes to make is to provide a strong, high quality National Water-Quality Assessment Program to underpin and unify the Nation's water-quality activities. Such an assessment program will satisfy a decisive share of the attainable, national scale, water quality information objectives.