Lake Assessment Program 1991 - Long and Spring Lakes, Meeker County, Minnesota

Long and Spring Lakes are located in Meeker County, near Dassel Minnesota. Long Lake has a surface area of 162 acres and a watershed of about 1,007 acres. Long Lake drains to Spring Lake. Spring Lake has a surface area of 202 acres and a watershed of about 2,276 acres. Both lakes are located in the North Central Hardwood Forest ecoregion and have relatively small watersheds relative to lake surface area (about 6.2:1 for Long and 11.3:1 for Spring). Land use in the watershed is dominated by agricultural (~ 30 percent), urban (~ 25 percent) and marsh/water (~ 30 percent) uses. Long and Spring Lakes were surveyed during the summer of 1991 by the Minnesota Pollution Control Agency (MPCA) staff and citizens from the Dassel Area Environmental Association. Water quality data collected during the study indicates that Long Lake is eutrophic with a mean total phosphorus concentration of 39 ug/L, mean chlorophyll a of 32.3 ug/L and Sechhi transparency of 5.3 feet. Water quality data for Spring Lake indicates that the is hypereutrophic with a mean total phosphorus concentration of 212 ug/L, mean chlorophyll a of 132.4 ug/L and Secchi transparency of 1.0 foot. These values (total phosphorus and chlorophyll) are much higher in Spring Lake than those values exhibited by representative - minimally impacted lakes in North Central Hardwood Forest ecoregion. The same values for Long Lake fall in line with the typical range for the NCHF ecoregion. Total phosphorus, chlorophyll a and Secchi transparency help to characterize the trophic status of a lake.