Grand County Lake Quality

There are 25 monitored lakes in Grand County. The mix is varied enough that the county-level average tells you the broad strokes, not the choose-this-cabin specifics. 6 of those lakes carry recent nutrient and algae readings. The county-level summary describes that subset, not every water body listed. For Grand County the spread behind the average matters more than the average itself: a few nutrient-rich lakes among many clear ones produce the same figure as the inverse.

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