1
DOtter Lake
Macoupin County, Wisconsin · 27.6 mi from Glenn Shoals Lake
- +Higher grade (F → D)
- +Lower phosphorus (37 vs 91 µg/L)
Cleaner Lakes Than Glenn Shoals Lake
1 higher-graded lake within 30 miles, ranked by grade improvement and proximity.
Glenn Shoals Lake carries a Grade F (Very Poor) water quality score. Within 30 miles, 1 lake holds a higher grade. Otter Lake (Macoupin County, Grade D, 27.6 mi away) is the closest meaningful upgrade.
How this list is built
Every lake on LakeQuality has a calculated grade from EPA Water Quality Portal samples — secchi depth, total phosphorus, and chlorophyll-a measured against Metropolitan Council thresholds. To suggest cleaner alternatives, we filter lakes within 30 miles to those with a strictly higher numeric score, then rank by grade improvement with a small proximity tiebreak. Cross-state and limited-data lakes are excluded so the list stays locally relevant.