St. Charles County Lake Quality

St. Charles County holds 14 monitored lakes. With a sample that small the county-level summary describes those specific waters, not necessarily every water body in the county. 2 of those lakes carry recent nutrient and algae readings. The county-level summary describes that subset, not every water body listed. For St. Charles County the spread behind the average matters more than the average itself: a few nutrient-rich lakes among many clear ones produce the same figure as the inverse.

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 L Ste Louise Lake.