Timm Lake
Yellow Medicine County, MinnesotaLimited DataEutrophic
On the LakeGrade rubric Timm Lake fails the cutoffs — a TSI of 67 and persistent algal pressure put it in the bottom tier. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.
At a TSI of 67, Timm Lake reads as eutrophic — nutrient-rich enough that summer algal growth and reduced clarity are expected, not unusual. The lake's maximum depth is not yet documented in state morphometric records — context for its physical structure remains limited. The lake's surface area is not consistently recorded across state datasets — physical context remains partial. Within the 5 graded lakes of Yellow Medicine County, Timm Lake sits at rank 5, near the bottom of the county list.
No invasive species are currently listed at Timm Lake — the lake remains off the Minnesota infested-waters roster. The state fisheries records do not list documented species for Timm Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. Public access is available — the lake is on the Minnesota PCA public-access list. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-05-13. Grade methodology: LakeGrade methodology.
Swimming Safety
Avoid swimming, very poor water quality, potential algae toxins
Water Quality Grade: F, Very Poor
Very murky, less than 2 ft of visibility. Trophic State Index: 67.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 2 ft | F |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 67 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Location
County Ranking
Ranked #5 of 5 lakes in Yellow Medicine County
Nearby Lakes in Yellow Medicine County
More Minnesota Lake Rankings
State Parks Near Timm Lake
Other Grade F Lakes in Minnesota
Eutrophic Lakes in Minnesota
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Timm Lake. 1 report on file.
- —Public Water Access Sites — TimmPublic Water Access Sites · MN DNR LakeFinder
Data Sources
Water quality data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Most recent sample: 2024-05-13
Monitoring stations: 1