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State Rep. questions EPA recommendation on lake water quality

Joyce Miller
The map shows the expansive watershed above Truman Lake that reaches into Kansas. The area above Truman is dominated by the Plains ecoregion. Regarding the map, first, most people do not realize just how expansive the watershed is above Truman dam. It’s very large and reaches far into Kansas. The watershed for Lake of the Ozarks is over 60% percent of the Plains ecoregion, not the more rocky Ozark landscape found directly around the Lake of the Ozarks. The state nutrient criteria is higher than the more restrictive levels for the Ozarks Highland ecoregion than it is for the Ozark Highland ecoregion. Missouri DNR has placed Lake of the Ozarks into the Ozarks Highland ecoregion, while Truman is in the Plains.

A recommendation by the Environmental Protection Agency to place Lake of the Ozarks and Truman Lake on the list of impaired waterways under the Clean Water Act is being challenged by some who disagree.

On Nov.30, 2020, the EPA partially approved, partially disapproved, Missouri’s 2020 303(d) List of impaired waters. MoDNR is required to submit the list every two years under the Clean Water Act (CWA). The list includes waterways in the state that exceed certain criteria, including elevated levels of several types of nutrients. Elevated levels of nutrients can cause algae. In this case, the nutrient that caught the attention of the EPA is chlorophyll-a.

Although DNR did not classify either Lake of the Ozarks or Truman Lake as impaired, EPA added the two bodies of water, along with 38 others in the state, to its list of recommendations. EPA disapproved the portion of the list that did not include the 40 additional lakes as impaired against the state’s chlorophyll-a numeric nutrient criteria. In other words, according to EPA, Lake of the Ozarks and Truman Lake have elevated levels of chlorophyll-a.

In its decision, the EPA said that there is sufficient existing and readily available water quality-related data and information that can be used to perform a reliable assessment of those waters under Missouri’s water quality criteria and designated uses. EPA is now seeking to list the 40 additional lakes as impaired for chlorophyll-a.

Richard Voss, who works with DNR’s water protection program in the monitoring and assessment unit, said as part of its decision process, which includes seeking public comment, the EPA has the authority to add waters that the agency believes to be impaired to the state’s 303(d) Lists. EPA is now requesting public comment on the addition of 40 lakes to Missouri’s 303(d) List that it believes to be impaired for nutrients.

According to Voss, EPA added these waters to the list because chlorophyll-a (algae) concentrations and lake responses to nutrient enrichment exceed Missouri’s numeric nutrient criteria. Lake of the Ozarks and Harry S. Truman Reservoir are two of the 40 Missouri lakes EPA identified as meeting the aquatic life-protection criteria for nutrient impairment.

“This means that the presence of excessive chlorophyll-a in these waters may impact the health and diversity of their aquatic life,” he said.

There have been no large fish kills reported at Lake of the Ozarks. A few small isolated incidents have been reported.

EPA issued a public notice on Dec. 7, 2020, providing for a 60-day public comment period on the 40 additions to Missouri’s CWA Section 303(d) List.

Local response

Lake-area State Rep. Rocky Miller said he believes it comes down to an issue of location. There is a group working on that issue with plans to submit recommendations to DNR and the EPA that could lead to the EPA recommendation being retracted.

Miller said DNR put Truman and Lake of the Ozarks in the Ozarks eco-region zone which has a much lower threshold for chlorophyll a. Both Truman and the Lake’s watersheds are in the Plains zone and therefore any testing done should reflect that zone’s limits.

“In addition, high chlorophyll numbers are not a human health hazard. They are the reason we have a great sport fish fishery here at the Lake. A fish kill in the upper reaches of the Lake is not wanted, but usually associated with droughts and low oxygen and therefore is not manmade, but an act of nature. This is truly a case of government overreach,” he said. “Lake of the Ozarks is one of the most tested waterways in the state and is and always has been safe for full-body contact and recreation.”

Camden County Commissioner Greg Hasty said Lake of the Ozarks is no stranger to federal agencies trying to over-regulate. He cited ongoing issues with the Federal Energy Regulatory Commission in 2006 regarding the Ameren Shoreline Management Plan. A FERC order regarding boundary lines along the lake in 2010 threatened more than 1,300 homes. That was followed by the Federal Emergency Management Agencies flood maps in 2011 placing thousands of homes in a special flood hazard zone that had no possibility of flooding. This time, he said, it is the EPA.

Hasty said any angler knows the fish population at Lake of the Ozarks is one of the most highly regarded in the United States.

“You can make a water quality survey come out however you want it to. These surveys are highly variable depending on where and when you take samples. Water quality assessments can be manipulated,” Hasty said.”Fish do not lie.”


EPA response

The process of assessing waters every two years and identifying those that are impaired is based on a comparison of monitoring data to water quality standards. It doesn’t typically include a specific analysis of the causes of impairment. However, for nutrient impairments, non-point source pollution is typically identified as the broad cause of impairment.

Generally, elevated levels of chlorophyll are due to elevated concentrations of nitrogen and phosphorus, typically referred to as eutrophication. Nutrient pollution is one of America's most widespread, costly and challenging environmental problems. Additional study and monitoring in both of these watersheds will help to further identify the causes of excess nutrients leading to eutrophication and impairment, and ultimately to practical place-based solutions to help improve water quality.

Missouri’s recently adopted nutrient criteria were established to protect aquatic life, and these impairments are specific to aquatic life, not human health. Too much nitrogen or phosphorus in a waterbody may result in overgrowth of aquatic plants, increased harmful algal blooms, decreased light penetration and decreased levels of dissolved oxygen. All of these may prove problematic for the health of aquatic species, and in some instances may cause conditions that lead to mortality in fish. EPA is aware that Missouri is evaluating nutrients as they relate to other designated uses including those related to human health.

EPA does not have any local meetings planned to take public comment. EPA issued a public notice providing for a 60-day public comment period on only these additions to Missouri’s CWA Section 303(d) List. After considering any comments received, EPA may make revisions, as appropriate, and will transmit its listings to Missouri for incorporation into the state’s water quality management plan.


What is chlorophyll a?

Chlorophyll-a is a pigment created by plants as part of photosynthesis. Algae are aquatic plants that occur naturally in lakes and streams. Chlorophyll-a is measured as surrogate for the amount of algae present in water. Algae is an essential part of the aquatic food chain for a healthy and balanced aquatic community.

Aquatic plants, just like the terrestrial varieties, produce and consume oxygen and carbon dioxide. Algae also consume nutrients (nitrogen and phosphorus) to grow and reproduce.

Excessive algal growth occurs when an overabundance of nutrients are available. The algae take advantage of the overabundance and rapidly reproduce. Rapid growth leads to greater production and consumption of oxygen and carbon dioxide. Excessive amounts of algae (chlorophyll-a) can cause detrimental effects to the aquatic organisms through wide swings (daily cyclical variations of high and low concentrations) in the amount of oxygen and the pH of the water. The effects of oxygen and pH swings can cause fish and other organisms to suffer directly (suffocation), or indirectly through stress which can increase the susceptibility of the organism to disease and infection.

Information provided by the Missouri Department of Natural Resources


EPA is soliciting public comments on the addition of these 40 water bodies on Missouri’s 2020 CWA Section 303(d) List for chlorophyll-a (W). After considering public comments and making any revisions EPA deems appropriate, EPA will send the listing to the state.

Written comments must be sent by email to on or before Feb. 5, 2021.

The public notice as well as the decision letter can be found here: