Blackwater Lake vs Long Lake
Water quality, depth, fish species, and recreation comparison.
Long Lake has a higher water quality grade (A, Excellent) than Blackwater Lake (A, Excellent). Both are in Cass County, Minnesota.
Both Blackwater Lake and Long Lake sit in Minnesota. A same-state comparison strips out the state-level water-quality regime as a variable: any grade differences here are about the lakes themselves, not the agencies grading them. The grades are close: Blackwater Lake (A) and Long Lake (A) are within one letter of each other on the LakeGrade rubric. The per-parameter sub-grades below will show where the small differences actually live.
With grades this close, the choice between the two lakes turns on non-water-quality factors: depth, fish species, public access, distance from home. The per-lake pages below cover all of those.
Blackwater Lake
Good clarity, visible to about 14.1 ft.
Long Lake
Crystal clear, you can see 21.5 ft down.
Side-by-Side Metrics
| Metric | Blackwater Lake | Long Lake |
|---|---|---|
| Overall Grade | A (Excellent) | A (Excellent) |
| Water Clarity | 14.1 ft | 21.5 ft |
| Phosphorus | 11 µg/L | 9 µg/L |
| Chlorophyll-a (Algae) | No data | No data |
| Maximum Depth | 67 ft | 115 ft |
| Surface Area | 771.45 acres | 1.0K acres |
| Public Access | Yes | Yes |
| Fish Species | 1 | 1 |
| Trophic State | oligotrophic | oligotrophic |
Bold value = better for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better).
Verdict
Long Lake wins on overall water quality with a Grade A versus Blackwater Lake's Grade A. Water clarity: 21.5 ft vs 14.1 ft. For fishing diversity, Long Lake also leads with 1 species.