Bay program historyThe Chesapeake B

Bay program history
The Chesapeake Bay Watershed covers 64,000 square miles and includes parts of six states (Delaware, Maryland, New York, Pennsylvania, Virginia, and West Virginia) and the District of Columbia. Fifty-eight percent of the watershed is forest cover, 23 percent is agricultural land (cropland and pasture), 9 percent is developed, and 10 percent is mixed open land.

The ecological health of the Bay is affected by a variety of pollutants, particularly the nutrients nitrogen and phosphorus, and sediment. In 2010 only 18 percent of tidal waters met or exceeded guidelines for water clarity; only 38 percent of the Bay and its tidal tributaries met Clean Water Act standards for dissolved oxygen; and less than half of stream health scores at monitoring sites were fair, good, or excellent (CBP, 2011).

Agriculture is the largest contributor of nutrients and sediment to the Bay. Crop production and animal operations contribute about 38 percent of total nitrogen loads, 45 percent of total phosphorous loads, and 60 percent of total sediment loads (National Research Council, 2011).

Efforts to reverse the decline in water quality are characterized by a decades-long ramping up of program goals and effort. Between 1976, when Congress directed the EPA to undertake a comprehensive study of the Bay's condition and what would be necessary to restore it to its former condition, and 2010, when the EPA established a Total Maximum Daily Load, multiple agreements between the Bay states and the Federal government were made and numerous assessments conducted. Even though the Bay Program stopped short of adopting regulatory approaches for meeting water quality goals, the duration of the effort highlighted the intent that goals eventually be achieved. The Chesapeake Bay TMDL is the largest ever developed by EPA, in terms of geographic coverage. It sets discharge limits for nitrogen, phosphorus, and sediment across six states (Delaware, Maryland, New York, Pennsylvania, Virginia, and West Virginia) and the District of Columbia that are necessary to meet applicable water quality standards in the Bay and its tidal rivers and embayments. Because of agriculture's share of pollutant contributions, meeting the TMDL goals will not be possible without substantial changes in the way agriculture is carried out in the watershed. Even though the TMDL does not mandate regulatory standards be imposed on agriculture and other nonpoint sources, the legal requirements of the TMDL are forcing states to consider expanding the set of policy approaches that have been traditionally applied to nonpoint source pollution.