Nebraska Lake Water Quality

Nebraska lists 592 lakes across 70 counties, 67 of them with a recent water-quality reading. Most of that sampling flows through monitoring run by the Nebraska Department of Environment and Energy, 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. Measured Nebraska lakes sit mostly in the middle of the nutrient range, with the highest phosphorus and algae readings in counties where row-crop agriculture dominates the watershed.

Lake Ogallala is the largest lake in this index at about 30,500 acres, one of 37 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. A meaningful share of the state's measured lakes register as hypereutrophic: heavily nutrient-loaded, frequent blooms, low summer transparency. These are usually shallow, surrounded by row-crop agriculture, with little volume to buffer the inputs. The county with the lowest nutrient and algae readings on average is Sherman. The gap between counties is large enough that a single figure for Nebraska lake water quality hides real local variation.