Lake Winona - Excess Nutrients: TMDL project

Lake Winona is located in west central Minnesota within the city limits of Alexandria. It has a watershed of 1432 acres and a surface area of 216 acres, a maximum depth of 10 feet and an average depth of 4 feet. The dominant land use within the watershed is urban, suburban. It is the first in a chain of lakes locally referred to as Agnes Henry Winona (AHW). Movement of flow through the AHW chain is from south to north, beginning at the Alexandria Lake Area Sanitary District (ALASD) wastewater treatment facility at the south end of Lake Winona. The chain of lakes drains north through Lake Le Homme Dieu, and Lake Carlos which discharges into the Long Prairie River. Lake Winona is located within the North Central Hardwoods Ecoregion.

The lake is listed as impaired due to excess nutrients, particularly phosphorus. The lake receives the treated effluent from the ALASD; that discharge has been documented to be a primary source of both flow and nutrients to the lake. Lake Winona also receives stormwater runoff from the city of Alexandria and other nonpoint urban runoff outside of Alexandria’s municipal boundaries. 

ALASD has conducted an ongoing lake monitoring program of Lake Winona and Lakes Agnes, Henry, and Le Homme Dieu since the late 1970s. An advisory group of stakeholders (representing city, county and state agencies and departments, ALASD, and local residents) was formed to help inform the Lake Winona TMDL project.

Map and location

Lake Winona is located in the city of Alexandria in Douglas County in north central Minnesota, within the Upper Mississippi River basin.

TMDL report and implementation plan

A TMDL draft was open for public comment on 12/5/2016 - 2/3/2017. Significant comments were received, and it was decided to wait until ALASD updated their wastewater permit before finalizing the TMDL. The permit for ALASD was approved in November 2020, and the TMDL has been updated to reflect the permit requirements for ALASD. 

Information contact

Bonnie Finnerty, MPCA Watershed Project Manager: or 218-316-3897.