Publications Available:

Mississippi and Alabama Reach TMDL Consent Decrees, Water Log Issue 19-4 (1999).

TMDL Authority Upheld for Nonpoint Source Pollution, Water Log Issue 20-2 (2000).

TMDL Rules Adopted in Rush to Beat Congressional Rider, Water Log Issue 20-2 (2000).

Since 1972, the Clean Water Act (CWA) has successfully reduced water pollution through the regulation of point source pollution. However, the CWA has done little to prevent the cumulative effect of pollutants from nonpoint sources such as farms, lawns and other locations left unregulated by the act. Because nonpoint source pollution has deleterious effects on coastal habitats, threatening the health of commercial and recreational fisheries, coastal economies, and diverse marine habitats, the federal government offered funding to coastal states to develop Coastal Nonpoint Source Pollution Programs. Gulf states have such plans but their effectiveness has been limited.

Under the Clean Water Act, states were to establish state standards for water quality under the Total Maximum Daily Load (TMDL) mandate by 1979. Nearly 20 years later, and after more than 15 years of nationwide litigation over the TMDL process, Mississippi and Alabama have joined more than 20 other states in establishing schedules for meeting the TMDL mandate.

TMDL is the total amount of a pollutant that a body of water can handle from all sources. Once a TMDL is calculated, it is used as a basis for putting limits on the amount of that pollutant that can be discharged into the river, lake or stream from all sources, while still allowing that body of water to meet its designated water quality standard. With the advent of the Clean Water Act (CWA) in 1972, Congress's main aim to "prevent, reduce, and eliminate pollution" of our water resources was through the reduction and regulation of point source pollution. With increased attention to other sources of water pollution, we discover that we have not reached our water quality goals because our permitting system does not satisfactorily account for the existing condition and flow of the waterway nor the cumulative effect of pollutants from nonpoint sources such as farms, lawns and other locations left unregulated by the act.

The Clean Water Act Section 303d establishes a method for controlling TMDLs. It states, "Each State shall establish . . . the total maximum daily load . . . established at a level necessary to implement the applicable water quality standards." It directs states to identify those waters within its borders that do not meet water quality standards despite the effluent limitations required by applicable permits. These waters are listed according to a particular use and even after the technology-based pollution controls are in effect. The list must prioritize those waters according to the severity of pollution and the importance of the body of water.

The next step is to determine the quantity of a specific pollutant, the total maximum daily load, that can be discharged into the waterbed without exceeding the water quality standard. Once this loading capacity is determined, the state then establishes a method for allocating the loading among both point and nonpoint sources. Finally, the states must limit pollution to the levels set by the TMDLs, allocating the amount of pollution quantified by a TMDL among the different polluters discharging into that body of water, and institute pollution controls to assure that the TMDL is not exceeded.

The nationwide litigation surge may not be complete, however, as there is active debate on which sources must be included in the TMDL. This debate centers on the inclusion of nonpoint source pollution in these load calculations. Some contend that section 303d was designed to include NPS - as a backstop applicable to all discharges when permit limitations fail to achieve water quality standards. Others claim that nonpoint sources are outside the purview of section 303d because Congress has addressed NPS pollution in other sections and other statutes and because it is virtually impossible to account for all sources of NPS pollution and assign portions of the TMDL. This will likely be determined in future litigation. Other litigious issues abound. For example, scientific judgments based on unproven methodologies or insufficient facts are susceptible to challenge. In addition, a state can probably expect challenges to the allocation of pollution burdens and the process by which the allocation was reached.

In the coming year, the Legal Program will analyze the effectiveness of two efforts to regulate nonpoint source pollution in coastal areas: Coastal Nonpoint Source Pollution Programs and state efforts to establish total maximum daily loads (TMDLs). Results of the research will be published in a law journal format and offered to coastal land use managers and planners.

For more information on TMDLs, visit:   

EPA TMDL Program Page