Lake Assessment Program: 2004 Skogman Lake & Fannie Lake, Isanti County, Minnesota

Skogman and Fannie Lakes are located in Isanti County, approximately three mile east of Cambridge, Minnesota (Figure 1). Skogman Lake has a surface area of about 215 acres with a maximum depth of 33 feet and a mean depth of about 11 feet. Fannie Lake covers about 393 acres and has a maximum depth of 36 feet and a mean depth of about 8 feet. The total watershed area for both lakes is approximately 11 square miles (Figure 2). Land use in the watershed is characterized primarily by wetland and forested uses and some remnant agricultural uses as well. As with other area lakes near municipalities, increases in urbanization of the watersheds are evident. The general land use composition for the lakes is quite comparable to other lake watersheds in this region of the state - North Central Hardwood Forests ecoregion. Skogman and Fannie Lakes were sampled during the summer of 2004 by the Minnesota Pollution Control Agency (MPCA) staff and citizens from the Skogman/Fannie Lake Association (Association). Water quality data collected during the study for Skogman and Fannie Lakes, respectively, reveal summer-mean total phosphorus (TP) concentration of 38 and 46 ?g/L; chlorophyll-a of 16 and 19 ?g/L and Secchi transparency of 5.6 and 4.6 feet. All of these measures are well within or better than the range of values exhibited by reference lakes in the NCHF ecoregion. Total phosphorus, chlorophyll-a and Secchi transparency help to characterize the trophic status of a lake. These measures indicate eutrophic – conditions for Skogman and Fannie Lakes. Both lakes are near the TP threshold (40 ?g/L) for placing lakes on the impaired waters (303(d)) list"