What's the Big Deal with TMDL's?

Waters of the State are classified by their intended uses. Some of these uses include drinking water, swimming, boating and canoeing, cold or warm water fishery, livestock watering, and industrial. For example, the uses for Table Rock Lake include Livestock and Wildlife Watering, Protection of Warm Water Aquatic Life and Human Health associated with Fish Consumption, Whole Body Contact Recreation, and Boating and Canoeing. If these uses can not be met due to pollution or habitat change, then the water is listed on the 303(d) list as impaired. Once a waterbody is placed on the 303(d) list, federal law requires the State to develop a plan to clean up the water.

The Total Maximum Daily Load or TMDL estimates the amount of pollution that can enter a waterbody while maintaining the intended use of that waterbody. The TMDL is determined by examining all contributing sources of a single pollutant (such as sediment), next, a numerical value is calculated to establish how much pollution can be added from each source each day, while keeping the water clean enough to maintain the intended use. The calculation includes a margin of safety, and accounts for seasonal variations so that the water will always meet the intended uses.

So, What’s Next for Missouri?
As of 2001, the EPA is under court order to establish TMDLs if Missouri does not. There are 174 waters on the 1998 303(d) list of impaired waters. Of those, 25 TMDLs have been written and approved by the EPA. Two drafts have undergone public comment, and will be sent to EPA for approval. That leaves 147 waterbodys that need a TMDL. In the next two years, MDNR must complete 40 TMDLs. The remaining waterbodys must have a TMDL in place by 2009.

The proposed 303(d) list for 2002 removes nine lakes for atrazine and cyanazine. However, 17 lakes are being added due to atmospheric deposition of mercury and three for Fecal Coliform. There will be 33 lakes on the list. Creve Coeur Lake is the only lake with an approved TMDL. Table Rock Lake is listed for both nutrients and mercury. Lake of the Ozarks is listed for fish trauma, gas supersaturation, and low dissolved oxygen.

What Can You Do?
Local citizens can assist the TMDL process by getting involved at the public meetings and identifying methods for reducing pollution that enters the waterbody. Nonpoint sources such as fertilized lawns, golf courses, leaking septic tanks and boat sewage discharges can be addressed by local action groups. Funding is available for education and installation of pollution reduction practices. Each proposed TMDL is listed on the department’s website for public notice. During that time your comments and insight are welcome.

For more information, visit:
www.epa.gov/owow/tmdl/ or: www.dnr.state.mo.us/deq/wpcp/wpc-tmdl.htm

Georganne Bowman

What the heck is this 303(d) list anyway?
303(d) refers to the section of the Clean Water Act which states:

303(d)(1)(A) “Each state shall identify those waters within its boundaries for which effluent limitations required by section 301(b)(1)(A) and 301(b)(1)(B) are not stringent enough to implement any water quality standard applicable to such waters. The State shall establish a priority ranking for such waters, taking into account the severity of the pollution and the uses to be made of such waters”

The state must determine which of its waters have problems with water quality. Then the state has to rank those waters on a list and address the list from the top down. The priority ranking may be based on how bad the pollution is as well as how people are intended to use the water.
The lakes on the 2002 list are shown here
Here is DNR's interactive map with the 303(d) listed lakes

Back to the Winter 2002 Waterline

Brought to you by the Lakes of Missouri Volunteer Program