Black Dog Lake in Burnsville, Minnesota, is part of the Minnesota Valley National Wildlife Refuge. The lake is classified as a Class 2B water (MPCA, 2021), suggesting that it supports warm-water fish and aquatic life (Statutes, 2021). Black Dog Lake is in the floodplain of the Minnesota River. Floodplain lakes, with their complex hydrology and ecosystems, are subject to periodic flooding that introduces water, sediment, and aquatic life.

This lake has historically been used by Xcel Energy for cooling water heated during electrical power generation at their Black Dog Generating Station. That generating station can be seen in the upper right (northeast) corner of the adjacent image.

Boat access to Black Dog Lake is limited to carry-in watercrafts. There is no information on fish populations and no records of fish stocking in the lake. However, there are anecdotal reports of people catching fish from the lake (Fishbrain, 2021). Because the water level is relatively shallow, the native fish population is subject to winterkills when the lake is covered by ice and snow.

Black Dog Lake has a maximum depth of about three feet (1.0 meter), but this depth may vary because of water-level control structures as well as the water level of the Minnesota River. Maps showing the depth (bathymetry) of Black Dog Lake have not been found.

Water quality monitoring activities for floodplain lakes have been either eliminated or reduced because of the regular intrusion of water from the Minnesota River. Sediment and paleolimnological assessments have been periodically completed to understand the quantity and quality of sediment deposition in some of the floodplain lakes from the Minnesota River. Water chemistry data for Black Dog Lake was not found. However, transparency and other indicators of biological activity have been measured since 2017 (UofMN, 2021). 

Monitoring Data

Transparency

The transparency (a measure of water clarity) of Black Dog Lake is good for a shallow lake. It is presumed that many of the readings, occasionally exceeding 1.0 meter (three feet), are limited by the depth of the water at the measurement site. Several readings exceed the criteria of 1.0 meter for Class 2B shallow lakes in Minnesota (Statutes, 2021).