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.
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 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.