Minnesota's Impaired Waters and TMDLs

TMDL Project: Wirth Lake - Excess Nutrients

Background

Wirth Lake is located in Hennepin County with most of its watershed within the city of Golden Valley. The remaining portion of the watershed, south of the lake is in Minneapolis and all of the shoreline around the lake is owned and managed by the Minneapolis Park and Recreation Board (MPRB). Wirth Lake is an important recreational resource to residents of north Minneapolis and surrounding inner-ring suburbs and it is used extensively for swimming, fishing, non-motorized boating, and aesthetic viewing. This lake is surrounded by significant wetland vegetation which provides excellent wildlife habitat. The Wirth Lake watershed is essentially fully developed and has a total area of 348 acres (excluding landlocked areas).  s noted in the Bassett Creek Water Management Commission (BCWMC) Watershed Management Plan (WMP, 2004) the city of Golden Valley, Minneapolis, the MPRB, and the BCWMC have been partners working to improve the water quality of Wirth Lake for several years. MPRB has worked on improving Wirth Lake for decades.

In 2004, Wirth Lake was placed on the Minnesota Pollution Control Agency’s list of impaired waters in need of a Total Maximum Daily Load (TMDL) study for excess nutrients, based primarily on data collected by the MPRB and the BCWMC. The data indicated that Wirth Lake has total phosphorus concentrations in excess of the MPCA’s state water quality narrative standard of 40 micrograms per liter for the growing season mean. The MPCA is partnering with BCWMC and MPRB to develop the work products necessary to complete a TMDL and implementation plan for Wirth Lake.

Map and location

Wirth Lake is located in Hennepin County, within the Mississippi River - Twin Cities watershed of the Upper Mississippi River basin.

TMDL report and implementation plan

•  Fact Sheet (wq-iw11-03a)
•  Final TMDL Report (wq-iw11-03e) 
•  EPA Approval Letter (October 25, 2010) (wq-iw11-03g)
•  TMDL Implementation Plan (October 25, 2010) (wq-iw11-03c)
  

Other documents

Previous reports/plans for Wirth Lake

• Wirth Lake TMDL work plan development meeting summary (February 8, 2008)
• Water Resources Report: Wirth Lake (2006, Minneapolis Park and Recreation Board)
• Wirth Lake Watershed and Lake Management Plan

Meetings and events

• June 24, 2010, Public Notice Meeting - 5:30 p.m. - 7:00 p.m., Theodore Wirth Park - Wirth Golf Chalet, Minneapolis
  •  Wirth Lake June 24, 2010, Public Meeting Information (wq-iw11-03t)
• June 22, 2009, Stakeholder Meeting #2 - 9:00 a.m.-11:00 a.m., Theodore Wirth Park - Wirth Golf Chalet, Minneapolis
  • Updated Modeling and TMDL Results - Greg Wilson, Barr Engineering Co.
    
    
•  February 17, 2009, Stakeholder Meeting #1 - 9:00 a.m.-11:00 a.m., Theodore Wirth Park - Wirth Golf Chalet, Minneapolis
  • Invitation flyer
  • Agenda
  • Presentations:
    • TMDL and Project Overview - Brooke Asleson, Minnesota Pollution Control Agency
    • Data Summary and Modeling Results - Greg Wilson, Barr Engineering Co.
  • Meeting Summary

See the TMDL Meetings, Events and News page for notices of general interest and event-related information on impaired waters/TMDLs.

Links

• Bassett Creek Water Management Organization
• Minneapolis Park and Recreation Board
• City of Golden Valley
• City of Minneapolis
• Minnesota Department of Natural Resources (DNR) “Information about Wirth Lake”
• Environmental Data Access- information on Wirth Lake
• Environmental Data Access information on Bassett Creek
• Sweeney Lake TMDL project Web page

Information contact

Brooke Asleson
Regional Division-Watershed Section
Minnesota Pollution Control Agency
520 Lafayette Road North
St. Paul, Minnesota 55155
651-757-2205
Brooke.Asleson@state.mn.us