Information on South Twin Lake

Ordinary High Water     888.30 ft. 

100-Yr. Flood Elev    889.7  (District, 100-year, 24 hour) 

South Twin Lake is a shallow lake with poor water quality. The lake and contributing watershed were recently annexed into the City of Stillwater.  A suburban development (Millbrook) is currently being constructed along the western shore. In-lake phosphorus concentrations commonly exceed the MPCA shallow lake standard of (60mg/L), and the lake is therefore listed as impaired.  In 2008 the lake did not meet the MPCA shallow lake standard of 1 m for sechi depth transparency.  South Twin along with North Twin, Silver, Carol, and Loon Lakes form the headwaters of the Silver Creek Flowage and a part of the Silver Creek Protective Corridor.  Current and future phases of the Millbrook development could pose additional problems if not managed properly and District permit conditions are not followed.  Potential stormwater discharge from future development outside (east) of the watershed district is also a concern.