Featured Collection Introduction: Chesapeake Bay Total Maximum Daily Load Development and Application

Abstract

The Chesapeake Bay Program (CBP), a state-federal partnership, is an ongoing experiment in how to restore the national treasure which is the United States’ (U.S.) largest estuary. The Chesapeake Bay experiment has now been running for three decades, but in 2010 a new tool was added to the restoration effort when the nation’s most extensive Total Maximum Daily Load (TMDL) program was established for the Chesapeake Bay watershed. The Chesapeake Bay TMDL marked a change in direction for the CBP partnership from a voluntary restoration program to one based on a regulatory form of allocations. The reasons for this pivot are outlined in the Executive Summary of the 2010 Chesapeake TMDL (USEPA, 2010). The Chesapeake Bay TMDL is based on the achievement of a suite of living resourcebased water quality standards for dissolved oxygen, chlorophyll a, and water clarity, which support fish, shellfish, underwater grasses, and other important aquatic life communities. The Chesapeake Bay TMDL incorporates several key elements. Scientifically based, publically understandable, water quality standards are the most important of these. The Chesapeake Bay water quality standards are based on requirements for the Bay’s living resources to thrive, including adequate dissolved oxygen in deep water habitats and good water clarity in the shallow waters necessary for growth of underwater grasses which provide habitat for juvenile fish and crabs. The partnership of state and federal agencies, which provides resource management governance and collaborative decision making for the entire watershed, is the second key element. This year the CBP marks its 30th anniversary. The CBP partnership was formed 30 years ago when the first Chesapeake Bay agreement was signed in 1983, recognizing the “historical decline of living resources” in the Chesapeake Bay and committing to a cooperative approach to “fully address the extent, complexity, and sources of pollutants entering the Bay.” It laid the foundation for a cooperative program that now includes all the Chesapeake Bay watershed jurisdictions. Finally, there is the long history of ever-increasing scientific understanding of the Bay ecosystem and the surrounding watershed. The underlying science enables the state and federal partners to agree on an equitable allocation of pollutant load reduction responsibilities. The JAWRA Featured Collection on the Chesapeake Bay TMDL tells the story of the