The Clean Water Act requires states to monitor their water resources to determine whether they are meeting water quality standards.  Waters that are violating standards are to be placed on an “impaired” waters list.  The state must then develop a cleanup plan called a “Total Maximum Daily Load” or “TMDL” for each water on the list. The TMDLs are a calculation of the largest amount of the impairment-causing pollutant that the water can receive while still meeting water quality standards.

The completeness of the impaired waters list depends on how many of Minnesota’s lakes, rivers and stream have been monitored and assessed for compliance with water quality standards.  As of the 2010 impaired waters listing cycle, the Minnesota Pollution Control Agency and its partners had assessed just 17% of Minnesota’s 92,000 miles of streams and rivers, and about 28% of lakes over 10 acres in size.  While clearly there is much more work to be done, assessment figures have increased substantially with added resources for water quality monitoring from the Clean Water Fund (the portion of the Constitutionally-dedicated sales tax proceeds devoted to clean water). Of waterbodies that have been assessed, roughly 40% are found to be impaired by one or more pollutant.

Click here to view maps of Minnesota’s assessed waters

Click here to see Minnesota’s inventory (spreadsheet) of impaired waters.  Note that there are two lists on this webpage.  The draft TMDL list is smaller and represents just those impaired waters that still need to have a TMDL prepared.  The inventory of impaired waters is larger, and represents all assessed Minnesota waters that are still impaired by one or more pollutants.

Click here to see TMDL studies that have been completed

MCEA has been very involved in several of the state’s cleanup plans.

Lake Pepin TMDL

The Lake Pepin TMDL started in 2005 to determine the maximum loads of phosphorus and sediment to the lake. A wealth of information relating to this massive TMDL are available here.  MCEA has been an active member of the stakeholder group for this study, and has submitted comments on the need for concrete reductions from agricultural sources, and expert testimony on the phosphorus goals for Lake Pepin.

Southeast Regional FC TMDL

MCEA challenged the initial TMDL for the Lower Mississippi River Fecal Coliform impairment in federal district court, after both the Minnesota Pollution Control Agency and US EPA failed to respond to MCEA’s comments on the draft TMDL. At issue were:  clean up goals that left many streams severely impaired by fecal coliform pathogens, contrary to the mandate of the Clean Water Act; the failure to address straight pipe septic systems as point sources; and the lack of a margin of safety.   MCEA won the case, the TMDL was remanded by the court to the MPCA to correct, and the US EPA was ordered by pay attorney’s fees to MCEA.  See MCEA’s original comments here; see the federal court decision here.

Lake Winona / ALASD (Alexandria Lakes Area Sanitary District)

Lake Winona is a shallow lake bordering the city of Alexandria, Minnesota. The lake has extremely high levels of phosphorus that generate algae blooms in the summer and degrade “downstream” lakes in this Chain of Lakes. The lake was listed as impaired for excess nutrients in 2002. The primary source of phosphorus is the local wastewater treatment facility, the Alexandria Lakes Area Sanitary District (ALASD). MPCA approved an expansion of the facility in 2006 and MCEA challenged that decision.

In that case, MPCA assured the Minnesota Supreme Court that the TMDL was underway, would be complete in 2009, and would result in a protective limit for ALASD that the facility would have to meet as soon as the TMDL was finished.  In fact, the TMDL study was not begun until two years later (2008).  MPCA’s contractor completed the draft TMDL in November 2009, which demonstrated that the ALASD’s phosphorus discharge needed to be slashed.  MPCA never finalized the TMDL or imposed the more stringent limit in ALASD’s permit.  Instead, the agency began work on a relaxed water quality standard for phosphorus for Lake Winona. (See MCEA’s letter of complaint to then-MPCA Commissioner Paul Eger here.)

The MPCA has not completed the process to adopt and seek US EPA approval for the relaxed standard (called a “site specific standard”). (See MCEA’s comments on the draft site specific standard here.)

Statewide Mercury TMDL

MCEA was actively engaged in the development of the largest TMDL in Minnesota. The statewide mercury TMDL covers 511 water bodies in the state and requires a 93 percent reduction in anthropogenic mercury emissions in the state from a 1990 baseline level.  Learn more about the TMDL and implementation plan are available here and read MCEA’s comments here.

Lower Minnesota River Low Dissolved Oxygen TMDL

This TMDL identified 40 point sources as the primary cause of low levels of dissolved oxygen in the lower 22 miles of the Minnesota River. Without oxygen in the water, aquatic life suffocates (as it does in the Gulf of Mexico dead zone). (See MCEA’s comments here.)

Lake Byllesby Site-specific Standard

Lake Byllesby is a reservoir on the Cannon River that suffers from massive algae blooms, some of which are toxic cyanobacteria (blue-green algae). The algae blooms are caused by very high levels of phosphorus in the Cannon River entering the reservoir. MPCA has developed a draft relaxed “site-specific standard” that would allow higher levels of phosphorus than the existing state standard. MCEA took issue with the proposed standard and submitted extensive comments and expert analysis requesting that US EPA disapprove the relaxed standard. Read MCEA's letter here.

Minnesota River Turbidity TMDL

High levels of sediment and suspended solids in the Minnesota River have led to a chocolate-colored river that is significantly contributing to the filling in of Lake Pepin. MCEA submitted comments on an early draft of the TMDL, which did not sufficiently identify the sources of the sediment.

Bald Eagle Lake Nutrients TMDL

Near White Bear Lake in the northeast metro area, Bald Eagle Lake is highly impaired from urban and rural sources. The draft TMDL called for major reductions from the “internal load” (phosphorus that has accumulated at the bottom of the lake), but not existing sources. It also ignored a source assessment that identified specific problems, notably three golf courses in the small watershed contributing most of the phosphorus to Bald Eagle Lake. MCEA submitted comments identifying these and other problems. [MCEA comments.]

Sweeney Lake Nutrients TMDL

This metro area lake in Golden Valley has high levels of nutrients that the TMDL proposed to reduce internally. MCEA commented on several issues including the source assessment and expected internal load reductions.

Carver Creek & Bevens Creek Turbidity TMDLs

MCEA submitted comments supporting approval of the Carver Creek and Bevens Creek TMDLs for turbidity. The draft TMDLs containted more detailed information than most draft TMDLs. By providing more thorough source assessment, individual MS4 allocations, a clear margin of safety, and strong assurances of nonpoint source reductions, the TMDLs can ensure that the public's money to clean up the creeks is well-spent. Local officials will know where to target implementation and will be able to measure progress toward achieving clean water. 

Peltier, Centerville, and Lino Lakes TMDLs

St Croix Lake TMDL

In January 2012, MCEA commented on the St Croix Lake TMDL regarding the use of land cover data from 1992 – 20 years before the TMDL would be approved – and other issues that MCEA has frequently raised. First, the draft TMDL assigned an aggregated pollution allocation to cities with municipal stormwater permits, even though there is no official process to disaggregate the allocation and the stormwater permits have limited oversight to ensure they make reductions. In addition, the TMDL lacked components needed for follow-up monitoring and reasonable assurance of nonpoint source reductions.

Pearl Lake nutrient and Mill Creek bacteria TMDLs

In February 2012, MCEA submitted comments on the Pearl Lake nutrient and Mill Creek bacteria TMDLs, requesting that MPCA require more detailed assessment of nutrient pollution sources and requesting that the nutrient TMDL meet water quality standards in critical conditions. MCEA also commented that the bacteria TMDL should consider straight-pipe septic systems point sources, because they discharge untreated waste directly to water. This was an issue that MCEA litigated in 2003, when the U.S. District Court of Minnesota concluded that “a pipe is a pipe, and the straight pipe septic system should be considered a point source.”