Maryland and the District of Columbia: Surface-Water Resources

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Excerpt from Introduction

Maryland and the District of Columbia both have abundant surface-water resources. In 1980, 72 percent of the population of Maryland and 100 percent of the population of the District of Columbia (table 1) depended on surface water to meet municipal water-supply needs. In 1980, 15,000 Mgal/d (million gallons per day) or 23,200 ft³/s (cubic feet per second) were used to generate hydroelectric power-the primary instream use of surface water. Offstream use primarily is for municipal and industrial supply; in 1980 this water use accounted for 98 percent of offstream surface-water usage in Maryland and 100 percent of offstream usage in the District of Columbia. In Maryland, where Groundwater and surface-water resources are used extensively, surface-water withdrawals amounted to 70 percent of the total water withdrawn in 1980. Groundwater, which provides the remaining 30 percent of water withdrawals, is used primarily in the Coastal Plain of Mary land where fresh surface-water supplies are less dependable.

The quantity and quality of surface waters and the mitigation of damages caused by floods are important issues in Maryland and the District of Columbia. State and local governments are being challenged to balance increasing demands by industry and municipalities for additional water supplies to sustain economic growth with the need for recreational areas for an expanding population.