Excerpt from Introduction
Maryland and the District of Columbia have abundant and economically important surface-water resources. Annual precipitation in these two areas is about 42 inches (U.S. Geological Survey, 1990, p. 291). In addition, an average of 30,000 million gallons per day enters the streams of Maryland and the District of Columbia from adjacent States. In 1985, surface-water withdrawals supplied public water-supply needs for 68 percent of the population of Maryland and 100 percent of the population of the District of Columbia (U.S. Geological Survey, 1990, p. 291). In addition to public supply, the streams and estuaries in the area also provide transportation, recreation, and scenic beauty. Water-Quality in most of the 93,000 miles of streams has been described as "good and stable," although problems exist locally (Maryland Department of the Environment, 1988, p. 5).