Since the mid-1960's, when Smith Mountain Lake was first filled, the lake has been a very popular and important multipurpose resource. An important function of Smith Mountain Lake, and the primary reason for its creation, is to provide hydroelectric power. Appalachian Power Company owns and operates Smith Mountain Dam as well as the dam on Leesville Lake just downstream from Smith Mountain. The two lakes together make it possible to operate Smith Mountain Dam as a "pumped storage" operation. In this arrangement water can be pumped from Leesvile Lake back into Smith Mountain Lake during periods of low power usage. AP Co. can thus be prepared for peak periods of power demand because the "power pool" in Smith Mountain Lake has been maintained at a high level.

Smith Mountain Lake is also a very popular recreation site, serving people from throughout the western part of Virginia. Thousands enjoy boating, swimming, fishing and other activities on the lake every year. Many resort homes, condominiums and year-round residences are located on the shores of this reservoir. A significant economic impact on localities around the lake results from recreational businesses, construction of homes and resorts, and the addition of new residents to the communities growing around the shoreline.

Smith Mountain Lake is presently used as a public water supply The water and shoreline of the lake provide habitat for many aquatic plants and animals, as well as birds and other terrestrial wildlife. The protection of aquatic life and other uses already mentioned for this lake is the goal of lake management activities.

Two rivers, the Blackwater and the Roanoke, are the main tributaries to Smith Mountain Lake. The Roanoke River is the larger of the two tributaries and drains a watershed that includes the Roanoke Metropolitan area. The Blackwater River's drainage is mostly rural and agricultural. A 1980 study indicated 72% of the phosphorus loading to Smith Mountain Lake came from the Roanoke River, and that at least 90% of this load was non-point source in origin. Recommendations were made and some of these were implemented. The Blackwater River arm of the lake was also found to have a relatively high eutrophication rate in its upper reach, a result attributed largely to non- point source. Agriculture was the biggest contributor of nutrients from runoff, with dairy farms yielding the highest loads per acre. Progress has been made in controlling some agricultural sources of nutrients through the State Water Control Board agricultural no-discharge permit program. In recent years, a number of these permits, which require approved methods for storage and disposal of liquid animal wastes, have been issued in the Blackwater River drainage area (Q).