Delivery of sediment and pollutants from nonpoint sources: A water quality perspective

Excerpt

In a 1984 report to Congress, the U.S. Environmental Protection Agency (EPA) concluded that nonpoint pollution was a leading cause of the nation's remaining water quality problems. Half of the states specified that nonpoint pollution was a significant water quality problem, and nearly every state reported some kind of water quality problem related to these sources.

Research suggested that lakes, including the Great Lakes; reservoirs; and estuaries, such as the Chesapeake Bay, were particularly vulnerable to nonpoint pollution. Recognizing the need for a massive, federal nonpoint pollution cleanup program, the EPA administrator called for redirecting existing federal, state, local, and private resources to assess nonpoint source problems of national significance (45).

Managers of nonpoint pollution abatement programs must identify land and define those land use activities that pose the most severe threat to receiving waters, so-called “hazardous land” (34). To define hazardous lands, information is needed on the strength of the pollution source and on attenuation of pollutants between the source and receiving water body.

Sediment delivery characteristics

In the 1950s, researchers studying sediment deposition in reservoirs noted that the quantity of sediment deposited in and passed through reservoirs was smaller than the upland erosion potential …