Northumberland County Lake Quality

Northumberland County holds 1 monitored lake. With a sample that small the county-level summary describes those specific waters, not necessarily every water body in the county. Every one of those lake carries recent nutrient and algae readings, so the county-level summary covers the full set rather than a monitored subset. Most monitored lakes in Northumberland County carry favourable nutrient and algae readings for Pennsylvania.

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. Shamokin Reservoir has the lowest nutrient and algae readings in the county.