Petroleum County Lake Quality

Petroleum County holds 4 monitored lakes. With a sample that small the county-level summary describes those specific waters, not necessarily every water body in the county. The 4 monitored lakes in Petroleum County carry whatever clarity, phosphorus, and chlorophyll-a readings Montana DEQ has published, shown as reported.

Most of the county's monitored lakes are shallow, under 50 feet, which means wind keeps the water column mixed all summer and sediment-bound phosphorus releases back into the surface layer whenever the bottom is disturbed.