Lewis and Clark County Lake Quality

There are 16 monitored lakes in Lewis and Clark County. The mix is varied enough that the county-level average tells you the broad strokes, not the choose-this-cabin specifics. 1 of those lake carry recent nutrient and algae readings. The county-level summary describes that subset, not every water body listed. Most monitored lakes in Lewis and Clark County are productive, shallow basins; each lake page shows its own phosphorus and chlorophyll-a 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 Lake Helena Outlet.