Missouri Lake Water Quality

Missouri lists 451 lakes across 93 counties, 203 of them with a recent water-quality reading. Most of that sampling flows through monitoring run by the Missouri Department of Natural Resources, which feeds state, federal, and volunteer measurements into the EPA Water Quality Portal. The remainder are here because they are real named lakes, not because anyone has sampled them recently. The measured lakes spread across the range: low phosphorus and algae readings in the deeper basins, higher readings in the agricultural south of the state.

Stockton Lake is the largest lake in this index at about 24,900 acres, one of 21 here that clear 500 acres. The rest run smaller, and small and shallow is where nutrient loading shows up first, because there is less water to dilute it and the bottom sediment stays within reach of the sun. The measured lakes lean eutrophic, with enough nutrient input to support an active algal community and the trade-offs in clarity and dissolved oxygen that come with it. The county with the lowest nutrient and algae readings on average is Clark. The gap between counties is large enough that a single figure for Missouri lake water quality hides real local variation.