Mead Lake TMDL


Mead Lake is a shallow, eutrophic impoundment of the South Fork Eau Claire River (Hydrologic Unit Code 07050006, Wisconsin Waterbody Identification Code 2137000). The Mead Lake watershed drains 248 km2 (61,282 acres) of west central Wisconsin. Approximately 99 percent of the watershed is within Clark County, with the remaining one percent in Taylor County. The South Fork Eau Claire River is the primary source of surface water inflow to Mead Lake. The lake was placed on the Wisconsin 303(d) impaired waters list in 1998 due to sediment and phosphorus. In 2008, the 303(d) list was updated to reflect that the pollutants of sediment and phosphorus are leading to impairments of degraded habitat, pH criteria exceedances, and excess algal growth in summer which result in limited body contact recreational use. The goal of this TMDL is to reduce phosphorus and sediment loadings to Mead Lake to address, pH criteria exceedances, decrease algal blooms in summer, and address degraded habitat so Mead Lake can be improved for recreational purposes.


Mead Lake is highly eutrophic and exhibits excessive concentrations of phosphorus and chlorophyll (a measure of algal densities) in its surface waters during the summer months (USACE 2005). Sediment and phosphorus enters the lake via the South Fork Eau Claire River, from nonpoint sources of pollution. Phosphorus is bound to the sediment particles, and once in the system, sediment has the capacity to transfer phosphorus to the lake bottom. The lake’s shallow depth, phosphorus-laden sediments and excessive water column phosphorus levels, cause the lake to experience severe algal blooms during the “growing” season (May-October). These eutrophic conditions have significantly impaired body contact recreational activities. In addition, algal blooms in Mead Lake are often accompanied by exceedances of the Wisconsin water quality criterion for pH. The elevated lake pH levels are due to removal of carbon dioxide from water during photosynthesis (by algae). The reduction in carbon dioxide levels during daylight causes an increase in pH. A reduction in sediment loading would reduce phosphorus levels and the corresponding reduction in phosphorus levels would result in a decrease in chlorophyll levels (a measure of productivity) and a reduction in maximum pH levels.

Related Reports

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TMDL/303d Projects
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Reports and Documents
Table 1 from the USEPA Decsion Document for the Approval of the Mead Lake TMDL 2143900
Lake Mead
The approval letter and decision document written by the EPA
Final TMDL Report
Data Documentation Mead Lake Impaired Waters Delisting Documentation, Clark County
Lakes Planning Report
Activities & Recommendations
TMDL (USEPA) Approved
TMDL Development for Mead Lake in Clark County, WI.
TMDL Development
TMDL Development for Mead Lake in Clark County, WI.
TMDL Development for Mead Lake in Clark County, WI.
TMDL Implementation
TMDL Development for Mead Lake in Clark County, WI.