Alleghany County Lake Quality

Alleghany County has 2 monitored lakes — a thin enough sample that one or two stressed lakes can move the county average noticeably. Use the per-lake pages below for what actually matters. Every one of those lakes carries recent nutrient and algae readings, so the county-level summary covers the full set rather than a monitored subset. On average, Alleghany County lakes carry some of the lowest phosphorus and chlorophyll-a readings in Virginia, with clear summer transparency across most monitored basins.

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. Dam Lake has the lowest nutrient and algae readings in the county.