EPA Transmits Final Clean Water Act 303(d) List of Impaired Waters to Missouri
LENEXA, KAN. (SEPT. 13, 2021) - The U.S. Environmental Protection Agency (EPA) has transmitted the final 2020 Missouri Clean Water Act (CWA) Section 303(d) List of Impaired Waters to the state. The Impaired Waters List is a state’s list of impaired and threatened waters (e.g., stream/river segments, lakes) requiring a Total Maximum Daily Load (TMDL). States are required to submit their list for EPA approval every two years.
“The 303(d) List is an important water quality monitoring and assessment tool,” said Acting EPA Region 7 Administrator Edward H. Chu. “EPA’s decision to identify these water bodies as impaired, including Lake of the Ozarks and Truman Lake, ensures that Clean Water Act protections for aquatic life are in place to safeguard against the impacts of nutrient pollution.”
A TMDL is the calculation of the maximum amount of a pollutant that can enter a water body without the water body exceeding applicable water quality standards.
On Nov. 30, 2020, EPA partially approved the Missouri Department of Natural Resources’ (MoDNR’s) 2020 Impaired Waters List. However, EPA disapproved the state’s decision not to list 40 water bodies, because the existing and readily available data and information for those water bodies indicated impairments of lake numeric nutrient criteria. Specifically, EPA identified these 40 water bodies for inclusion on Missouri’s 2020 CWA Section 303(d) List for chlorophyll-a. Included among these 40 water bodies are Lake of the Ozarks and Truman Lake.
EPA relied on available data and the state’s listing methodology to add additional impaired water bodies not identified by the state. On Dec. 7, 2020, EPA provided public notice that it was soliciting public comments on the addition of the 40 water bodies as impaired. That public comment period was set to expire Feb. 5, 2021. In order to provide additional time for the public to participate in the comment period, the Agency extended it until March 22, 2021. EPA is transmitting the final list after evaluating comments received during the public comment period. The Response to Comments document is available online.
The water bodies identified in the list are impaired by chlorophyll-a for aquatic life. Today’s action is focused on the protection of aquatic species.
This action does not address nutrient impairments for recreational or drinking water uses; however, EPA encourages the state to update Missouri nutrient criteria for lakes and streams. EPA encourages the public to check local water conditions at MoDNR’s website.
For additional information regarding harmful algal blooms, please visit EPA’s website.
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