Degraded water and TMDL compliance

The EPA announced that it provided the state with the 2020 Missouri Clean Water Act (CWA) Section 303 (d) final list of degraded waters on September 13, 2021.

Section 303 (d) of the CWA requires states to submit their lists of degraded waters to the EPA for approval every two years.

“The 303 (d) list is an important tool for monitoring and assessing water quality,” said Edward H. Chu, EPA Region 7 Acting Administrator, in the press release. the EPA. “The EPA’s decision to identify these water bodies as altered… ensures that [CWA] protections for aquatic life are in place to guard against the impacts of nutrient pollution.

“The objective of the law is to restore and maintain the chemical, physical and biological integrity of the country’s water,” says the degraded water section on the EPA website. “One of the objectives is to achieve water quality that is both“ fishable ”and“ swimmable ”by the mid-1980s. Although the date has passed, the objective remains and the efforts to improve it. ‘reach continue. The regulations governing degraded waters can be found in 40 Code of Federal Regulations (CFR) 130.7.

In addition to a list of degraded waters, state reports submitted to the EPA should include:

  • A description of the method used to establish the list of degraded waters,
  • The data and information used,
  • The justification for the decision,
  • A list of all the waters that may soon become deteriorated,
  • Priority ranking according to the severity of the pollution and the designated use of the body of water,
  • A list of pollutants to be regulated,
  • Plans to establish a total pollutant load and analyze the load of point and diffuse sources with a safety margin, and
  • Total maximum daily load (s) (TMDL) of pollutant (s) in the water body for the degraded waters on the list.

A TMDL is the calculation of the maximum amount of a pollutant that can enter a body of water without exceeding the applicable water quality standards for that particular body of water.

Typically, one TMDL is developed for each pollutant that threatens a body of water, so a body of water may have more than one TMDL in place at a time, “reports the National Agricultural Law Center. “Although it is more common for a TMDL to treat a specific pollutant, in some cases a single TMDL can be developed to treat multiple pollutants in a water body or watershed. “

The National Agricultural Law Center adds that a “TMDL should clearly identify the link between the degradation of the water body, the causes of the degradation and the pollutant reductions needed to meet relevant water quality standards. If the EPA does not approve a state’s TMDL, then the [EPA] will develop its own TMDL for the lake.

“Once a TMDL is approved, it is implemented through a combination of CWA permits and a variety of state, local and federal programs. Point and diffuse sources of pollution will be affected by the TMDL pollutant reduction requirements. Under the CWA, anyone who discharges a pollutant into a body of water from a point source, an identifiable source such as a pipe or ditch, must obtain a permit from the EPA. Once a TMDL is established for a water body, point source permits will establish pollutant limits based on the TMDL. Pollution that enters a body of water through a diffuse pollution source, such as agricultural runoff or sediment erosion, does not require a CWA permit. Therefore, state, local and federal programs help regulate pollution from non-point sources in order to meet TMDLs relevant for a particular waterway.

In the case of Missouri, the EPA partially approved the 2020 list of degraded waters from the Missouri Department of Natural Resources (MoDNR) on November 30, 2020.

“However, the EPA disapproved of the state’s decision not to list 40 water bodies because existing and readily available data and information for those water bodies indicated alterations in the numerical nutritional criteria of the lake,” indicates the press release of the Agency. “Specifically, the EPA has identified these 40 water bodies for inclusion in the 2020 Missouri Section 303 (d) CWA list for chlorophyll-a.

“The EPA relied on available data and the state’s listing methodology to add additional degraded water bodies not identified by the state. “

It should come as no surprise that the EPA decided to add more waters to the state’s list of degraded waters. According to the EPA Water Quality Assessment and Information website TMDL, 70.9% of assessed lakes, reservoirs and ponds in the United States are classified as weathered. For rivers and streams, 52.9% of those assessed are classified as degraded, and 79.5% of bays and estuaries assessed are considered degraded. These numbers do not include wetlands, the Great Lakes, coastal shorelines, or ocean waters.

These figures also do not take into account the water bodies that are not assessed, which include 31.4% of rivers and streams; 55.3% of lakes, reservoirs and ponds; and 36.1% of bays and estuaries.

In 2014, the EPA reported that more than 70,000 TMDLs had been completed. However, analyzing the results is difficult “because the entire sequence of developing TMDL, implementing TMDL, and recovering altered water often takes several years,” according to the Impaired Water Restoration Process section of the article. EPA website.

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