Cedar Lake TMDL

Purpose

The Wisconsin Department of Natural Resources (WDNR) developed a TMDL for phosphorus for Cedar Lake. The TMDL addresses the nutrient impacts and impairments which were identified on the Wisconsin 2002 303(d) list. The Lake is nutrient (phosphorus (P)) impaired as a result of agriculture, internal loading and local land use. Water quality in Cedar Lake is generally poor to very poor, falling into the eutrophic to hypereutrophic category. Summer algal blooms result in foul odors and an unsightly build-up of algae biomass on the shoreline. In addition, trophic conditions in the lake limit rooting depth for emergent vegetation used by the resident fish populations. As a result, these impairments impact the recreational/aesthetic value of the lake and stress sport fish populations.

Objective

This project will assess watershed phosphorus loadings and the three major sources of internal loadings in 2009 and 2010. WDNR will consider that Cedar Lake is meeting the narrative water quality standard when the algal growth is reduced. To do this, WDNR has established a water quality target of 50 μg/l of total phosphorus. The TMDL discusses future monitoring to demonstrate whether or not progress has been made towards establishment of the water quality target. This includes water quality monitoring as well as more comprehensive data collection.

Outcome

The Cedar Lake TMDL required widespread BMP implementation through the Horse Creek Lakes priority watershed project and whole lake mixing by aeration. After implementation the lake remains to have a significant internal phosphorus load as growing season total phosphorus levels increase by a factor of 2-4 from April to September.

QA Measures

Run Project Summary Report

TMDL/303d Projects
Implement TMDL
Cedar Lake TMDL
2003
Active
 
Reports and Documents
'After a full and complete review, EPA finds that the TMDL for Cedar Lake satisfies all of the elements of an approvable TMDL. This document addresses a total of 1 TMDL for 1 waterbody with a total of 2 impairments from the 2002 Wisconsin 303d list.
Cedar Lake Phosphorus TMDL Revised June 1, 2003 Revised July 1, 2003. Revised July 3, 2003.
Data Documentation Cedar Lake Impaired Waters Delisting Documentation, St. Croix and Polk Counties
 
Activities & Recommendations
TMDL (USEPA) Approved
The Cedar Lake TMDL required widespread BMP implementation through the Horse Creek Lakes priority watershed project and whole lake mixing by aeration. This project will assess watershed phosphorus loadings and the three major sources of internal loadings.
 
Waters