Baseline water quality of Schmidt, Hornbeam, and Horseshoe Lakes, Dakota County, Minnesota

Three lakes in Dakota County were sampled five times during an 18-month period to determine baseline water quality prior to construction of an interstate highway. Results of physical measurements and chemical analyses showed that the lakes were shallow, nonstratified, and nutrient enriched. Considerable seasonal variations in dissolved solids, nutrient, and dissolved-oxygen concentrations were observed. Oxygen depletion and high nutrient concentrations were characteristics of conditions under an ice cover. Blue-green algal blooms typically were established soon after ice breakup and persisted until late fall. Data from the study will be supplemented with data--collected during and after construction of the highway to assess the impact of highway construction s \d drainage on water quality of the lakes.