Lake Assessment Program - Dunns and Richardson Lakes, Meeker County

Dunns and Richardson Lakes are located in Meeker County. Dunns and Richardson Lakes have surface areas of 151 and 111 acres respectively. The total watershed is about 5,656 acres including both lakes. Land use in the watershed is characterized primarily by and cultivated (73 percent) pasture ( 17 percent) uses. The cultivated use percentage is somewhat higher than typical for lake watersheds in this ecoregion of the state - North Central Hardwood Forests ecoregion. Dunns and Richardson Lakes were sampled during the summer of 1996 by Minnesota Pollution Control Agency (MPCA) staff and citizens from the Dunns and Richardson Lakes Association (Association). Dunns Lake is rather shallow (Zrn., = 20 feet) and remains well mixed. Richardson Lake is deeper (Zm.x = 47 feet) and stratifies during the summer. Water quality data collected during the study reveal summer-mean total phosphorus (TP) concentration of 111 and 59 ?g/L, mean chlorophyll J! of67 and 35 ?g/L and Secchi transparency of2.3 and 5 feet for Dunns and Richardson Lakes respectively. The phosphorus, and chlorophyll J! concentrations for Dunns and Richardson Lakes are greater than the range of values exhibited by reference lakes in this ecoregion, while the Secchi value is lower than what would be exhibited by reference lakes for Dunns Lake and within the range of values for Richardson Lake. Total phosphorus, chlorophyll J! and Secchi transparency help to characterize the trophic status of a lake. These measures indicate eutrophic conditions for Dunns and Richardson Lakes.