A TMDL Primer

• By Lisa Rademakers
• Mar 01, 2001

The Clean Water Act (CWA) establishes a comprehensive program "to restore and maintain the chemical, physical and biological integrity of the Nation's waters." To achieve this statutory objective, the CWA has traditionally relied upon technology-based controls to limit discharges from point sources through the permit requirements of the National Pollutant Discharge Elimination System (NPDES) under Section 402 of the CWA. However, today the majority of America's waters still do not meet existing water quality standards.

Section 303 of the Clean Water Act outlines a water quality regulatory approach for managing pollution in waterbodies where technology-based effluent standards have failed to achieve the primary objective of the CWA. Subsection (a) requires the states to adopt water quality standards (WQSs) and to submit them to the U.S. Environmental Protection Agency (EPA) for approval. Subsection (b) requires EPA to establish WQSs when a state either fails to submit them or if the submitted WQSs are inconsistent with the CWA. Subsection (c) requires states to review and revise WQSs every three years and includes the applicable criteria for revised WQSs. Subsection (d) requires states to identify waters (a.k.a., water quality-limited segments or WQLSs) that do not meet WQSs and to establish total maximum daily loads (TMDLs) for these WQLSs. Subsection (e) requires the states to establish a continuing planning process for ensuring that all waters will meet WQSs.

Under CWA § 303(d), TMDLs are required to be developed for WQLSs which are those water bodies or portions thereof that do not meet WQSs even after the application of technology-based controls under the NPDES program requirements. The TMDL program was designed to provide a safety net, catching water bodies that were not protected or restored by the implementation of the range of general, broadly applicable, pollution control programs authorized in the Clean Water Act.¹ The TMDL program is aimed specifically at assuring attainment of water quality standards.

Under CWA § 303(d), the states are required to identify WQLSs for which technology-based controls are insufficient to meet applicable water quality standards and to prioritize those WQLSs targeted for TMDL development over the next two years. The priority ranking and the list of waters targeted for TMDL development must reflect the severity of use impairment and the type of uses being impaired. This list of impaired waters is referred to as a state's 303(d) list and is submitted to EPA every two years. The 303(d) list provides a comprehensive inventory of water bodies impaired by all sources, including point sources, nonpoint sources, or a combination of both. The EPA must either approve or disapprove a 303(d) list within 30 days after submission. If EPA disapproves a 303(d) list, then the agency must identify WQLSs for the state within 30 days after the date of disapproval.

TMDLs must be established for all pollutants (chemical, physical or biological) preventing or expected to prevent attainment of water quality standards as identified by the WQLSs on a state's 303(d) list. A TMDL is the sum of the individual wasteload allocations (WLAs) for point sources and load allocations (LAs) for nonpoint sources and natural background sources. A WLA is that portion of a receiving water's loading capacity that is allocated to one of its existing or future point sources of pollution. A LA is that portion of a receiving water's loading capacity that is attributed either to one of its existing or future non-point sources of pollution or to natural background sources. TMDLs must be established at levels necessary to attain and maintain applicable narrative and numerical WQSs allowing for seasonal variations and including a margin of safety, which accounts for any lack of knowledge concerning the relationship between effluent limitations and water quality. EPA is required to either approve or disapprove a TMDL within 30 days after submission. If EPA disapproves a TMDL, then the agency must establish the TMDL for the state within 30 days after the date of disapproval.

Once approved or established by the EPA, a TMDL is implemented through the use of both point and nonpoint source controls. Point source controls are achieved through the NPDES permit process. NPDES permit limits which implement a TMDL are known as water quality-based effluent limits (WQBELs). A WLA is incorporated into NPDES permits through a corresponding WQBEL. Effluent limits which are developed to protect a water quality criterion must be consistent with the assumptions and requirements of any WLA for the discharge which has been prepared as part of a TMDL. LAs, on the other hand, are implemented by utilizing the State's CWA § 319 nonpoint source management program which includes Best Management Practices (BMPs), Coastal Zone Act Reauthorization Amendments management measures, regulatory processes, siting criteria, and/or operating methods for controlling nonpoint source pollution.² Nonpoint source controls are implemented on a local, regional and/or statewide level as appropriate.

Beginning in the 1980s and gaining momentum in the early 1990s, a continuous series of citizen lawsuits have been brought against EPA by environmental advocacy groups primarily alleging the existence of a mandatory duty under the CWA for EPA to establish WQLSs and/or TMDLs when a state has failed or chosen not to. In Scott v. City of Hammond ³ the U.S. Court of Appeals for the Seventh Circuit determined that a "prolonged failure" by a State to submit TMDLs over a long period of time (i.e., "state inaction amounting to a refusal to act") may amount to a "constructive submission" of no TMDLs by the State. Such a "constructive submission" would trigger EPA's duty to approve or disapprove such submission of no TMDLs by the states and to establish TMDLs if there was a disapproval.

This "constructive submission" theory became the basis for additional TMDL citizen suits⁴ in the late 1980s and early 1990s in Oregon, Alaska and Minnesota. Of particular significance, in Alaska Center for the Environment v. Reilly a district court found for the first time that a state had constructively submitted no TMDLs and ordered EPA to initiate its own process of establishing TMDLs including identification of WQLSs. In Sierra Club v. Browner EPA had disapproved Minnesota's § 303(d) listing, but the district court could not find that there had been a "constructive submission" of no WQLSs or TMDLs. The state had submitted 43 TMDLs that were approved by EPA and there was evidence that the state was working on other TMDLs.

In Dioxin/Organochlorine Center v. Clarke⁵ EPA had established a TMDL for dioxin for the Columbia River at the request of Oregon, Washington and Idaho that was challenged by both environmental groups and paper mills for not conforming with applicable WQSs and for being issued prior to the establishment of less burdensome technology-based (i.e., best available technology) effluent limitations. The district court upheld EPA's establishment of the TMDL and also concluded that the CWA does not require that TMDLs be issued for all pollutants at once. The district court in Idaho Sportsmen Coalition v. Browner⁶ found EPA's approval of Idaho's 1992 303(d) list to be contrary to law and ordered EPA to promulgate a 303(d) list for Idaho. In 1992, Idaho had submitted a 303(d) list containing 36 WQLSs which EPA approved despite the existence of available information indicating that there were hundreds of WQLSs. The district court also ordered EPA to develop a reasonable TMDL schedu le in cooperation with Idaho. However, the district court did not find that a "constructive submission" of no TMDLs had occurred yet since Idaho had submitted three TMDLs and was working on developing other TMDLs.

Several environmental organizations brought a citizen suit to compel EPA to identify WQLSs and to establish TMDLs in Georgia in Sierra Club. V. Hankinson⁷. The district court found that the two TMDLs submitted by Georgia after the filing of this action were inadequate and that EPA's approval of these TMDLs was arbitrary and capricious. In addition, the district court found that EPA had also violated the CWA by not promulgating TMDLs for Georgia given the state's failure to submit timely and adequate TMDLs. The district court, however, did not find that a "constructive submission" had occurred because Georgia had made some TMDL submissions despite having been inadequate. Later⁸ the district court ordered EPA to establish TMDLs for all WQLSs identified on Georgia's existing 303(d) lists within 5 years.

In response to these and other lawsuits, EPA established the Federal Advisory Committee on the TMDL Program in November 1996 for the purpose of providing recommendations with regard to the 303(d) program. In July of 1998, the Committee released its recommendations in the "Report of the Federal Advisory Committee on the Total Maximum Daily Load (TMDL) Program." These recommendations led to the development of revisions to the TMDL regulations. On July 13, 2000 EPA published in the Federal Register (65 FR 43586) its final "Revisions to the Water Quality Planning and Management Regulation and Revisions to the National Pollutant Discharge Elimination System Program in Support of Revisions to the Water Quality Planning and Management Regulation." The significant revisions include⁹:

• 303(d) List development changed from every two years to every four years. States have the discretion to include "threatened" waters on their 303(d) Lists. States are now permitted to add or remove listed polluted waters at times other than the four year 303(d) listing cycle.

• States are to provide a comprehensive listing of polluted waters, those needing TMDLs as well as others, and are to track these waters until water quality standards are met. States are to develop a methodology for assessing the health of waters and listing polluted waters with the involvement of the public and EPA.

• States can justify a different prioritization of impaired waters on their 303(d) Lists instead of being required to give higher priority to certain impaired waters. However, there is a "rebuttable presumption" that states will give high priority for development of TMDLs to waterbodies where the problem pollutant is causing a drinking water system to violate a drinking water standard or where the waterbody supports threatened or endangered species.

• Implementation plans for TMDLs are required, but the requirements have been simplified to allow States to adapt them to local conditions. Implementation plans must provide a date by which the State expects water quality standards will be attained and this date must reflect a goal of meeting water quality standards as expeditiously as practicable. If such date is not within 10 years of establishment of the TMDL, then the State must demonstrate with credible and scientific information that this is not reasonable.

• States are to develop TMDLs as expeditiously as practicable, at an even pace, but not later than 10 years after the first listing of a polluted waterbody, unless EPA grants an extension of up to 5 years for schedules where establishment of TMDLs within 10 years is not practicable.

• States are to provide the public with notice and an opportunity to comment on lists of polluted waters, listing methodologies, modifications to these lists and TMDLs.

• EPA is required to develop TMDLs within two years when EPA disapproves a TMDL submittal and when a State fails to make substantial progress under an approved schedule.

• EPA is required to establish lists of polluted waters and schedules for TMDL development when EPA disapproves a list/schedule and when a State does not submit a list/schedule by April 1 of 2002 and every four years thereafter.

Although the EPA's recently revised TMDL regulations are final, a Congressional rider attached to an appropriations bill (H.R. 4425) signed by President Clinton in July 2000 prohibits the EPA from spending any funds on implementing the new TMDL regulations until October 1, 2001. Until that date, the existing TMDL regulations at 40 C.F.R. (Code of Federal Regulations) § 130.7 (July 2000) are still the effective TMDL regulations. Further information regarding EPA's TMDL program or the status of TMDL litigation can be found at www.epa.gov/owow/tmdl.