Macoupin County Lake Quality

There are 17 monitored lakes in Macoupin County. The mix is varied enough that the county-level average tells you the broad strokes, not the choose-this-cabin specifics. 3 of those lakes carry recent nutrient and algae readings. The county-level summary describes that subset, not every water body listed. The monitored lakes here are mostly shallow, productive basins where summer algae is common; each lake page shows its own readings beside the EPA condition class.

The county's lakes lean shallow, which makes the readings sensitive to wind, sediment-resuspension, and any nutrient inputs from the watershed. The cleanest measured lake is Palmyra-Modesto Lake.