EPA's Total Maximum Daily Load (TMDL) process was established by Section 303(d) of the Clean Water Act to protect public health and water quality on a watershed basis.
States list polluted waters (so called 303(d) lists) and then determine the maximum daily load of pollutants (including nutrients) that those waters can receive and still meet water quality standards. These loads are then allocated to point and nonpoint sources of pollution and a margin of safety is built in. An action plan is then established to reduce pollutants to this level, using existing enforcement mechanisms (such as NPDES permits).
EPA came under fire from environmental groups for not enforcing the TMDL Program in certain states. As a result, in August 1999, EPA proposed changes to its existing regulations to clarify and strengthen the authorities of EPA and States to implement the TMDL program. This proposed TMDL Rule was the subject of much political debate, including several Congressional bills.
The Final TMDL Rule was published in the Federal Register in July, 2000 but a Congressional rider prohibited EPA from implementing this rule until October 2001. EPA subsequently issued a delay of the effective date until April 2003. During this time period, EPA will attempt to revise the TMDL Rule in order to make the final version more workable for industry.
