Platte County Lake Quality

Platte County's 19 monitored lakes fall in the moderate-density bracket for Wyoming. The county-level average smooths over real differences — a single agricultural watershed near the southwest corner can pull the average down even if the rest of the county runs clean. 9 of those lakes carry an A–F grade. The county-level summary describes that subset, not every water body listed. The county-wide average lands at B — solid water quality with most lakes carrying clear summer transparency and low-to-moderate phosphorus.

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. Glendo Reservoir Riverine Pelagic (B) is the cleanest in the county.