Blue Lake Priority Action Plan Phase II

The project goal to continue our mission to improve the quality of Blue Lake and ensure the lake does not get listed as impaired during the next MPCA assessment cycle for the Rum River Watershed. Previous assessments indicated the lake was not impaired; however, recent data indicates the lakes? 10-year average Total Phosphorus (TP) and Chlorophyll-a hover just above State Standards. The project we are proposing will result in a 590 pound/year reduction of TP; this will bring the lake back into the ?protection zone.?

We aim to accomplish our goal by applying a buffered alum treatment to all lake areas greater than 20 feet deep, as recommended in the Alum Feasibility Study. The specific treatment area was identified as the most cost-effective option in the study. The treatment will be split into two ? doses; the first applied in 2022 and the second in 2024.

A Diagnostic Study done by Wenck concluded that the lakes protection goal, as set in the Rum River Watershed Restoration and Protection Study (WRAPS), requires a 360-pound reduction of TP. In addition, the study identified internal loading as the root cause of degraded water quality; it currently contributes 595 pounds/year of phosphorus.

The SWCD is currently working to reduce 102 pounds per year from upland sources (as recommended in the Diagnostic Study); we have already reduced upland TP loading by over 40%. We did this by implementing the most cost-effective projects as identified in a Subwatershed Assessment Study; a 2018 Clean Water Fund Grant funded these projects. Except for addressing the internal load, the less cost-effective practices remain. We continue to work to reduce upland phosphorus using other sources of funding.

The SWCD and its partners have identified a path to improved recreation in Blue Lake, and an Alum treatment is the next logical and cost-effective step.