Bass Lake
Otter Tail County, MinnesotaEutrophic
Bass Lake sits at a C on the grading scale — not impaired, not pristine, with summer measurements that vary year to year. With clarity and phosphorus scored, the sub-grades cluster within a letter of each other, pointing to stable conditions rather than one specific stressor.
At a TSI of 54, Bass Lake reads as eutrophic — nutrient-rich enough that summer algal growth and reduced clarity are expected, not unusual. The lake bottoms out at 36 ft — a moderate depth that supports a warm-water fishery without the year-round cold refuge a deeper basin provides. At 311 acres, Bass Lake fits the Minnesota median for monitored lakes, with 5.6 miles of shoreline. Bass Lake ranks 83 of 97 in Otter Tail County — at the lower end of the locally monitored distribution.
Bass Lake has no invasive species recorded in Minnesota state databases as of 2024, though prevention practices still apply at all access points. The fishery includes walleye among the lake's 7 documented species — a notable draw for Minnesota anglers. 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 2024-09-15. Grade methodology: LakeGrade methodology.
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Swimming Safety
Generally safe for swimming, moderate water quality
Water Quality Grade: C, Fair
Murky, only visible to about 5.9 ft. Phosphorus level: 40 µg/L. Trophic State Index: 54.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 5.9 ft | D |
| Phosphorus | 40 µg/L | C |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 54 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 36 ft |
| Surface Area | 310.92 acres |
| Shoreline Length | 5.6 mi |
| Littoral Zone | 44% |
| Public Access | Yes |
Fish Species
Click a species to see all Minnesota and Wisconsin lakes where it is found.
→ Best fishing times for Bass Lake (14-day solunar calendar)
→ Is it safe to eat fish from Bass Lake? (mercury & PFAS guide)
→ Bass Lake fishing regulations (limits, seasons, special rules)
Water Quality Trend: → Stable
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Phosphorus | → Stable | +0.45 µg/L/yr | 4 |
Location
County Ranking
Ranked #83 of 97 lakes in Otter Tail County
Cleaner Lakes Within 30 Miles
Bass Lake holds Grade C. 3 nearby lakes hold higher grades.
- BSouth Turtle LakeOtter Tail County · mi · Higher grade (C → B)
- BWall LakeOtter Tail County · mi · Higher grade (C → B)
- CStalker LakeOtter Tail County · mi · Higher overall water quality score
Nearby Lakes in Otter Tail County
More Minnesota Lake Rankings
State Parks Near Bass Lake
Other Grade C Lakes in Minnesota
Eutrophic Lakes in Minnesota
DNR Fisheries Survey Summary
5 surveys on file from MN DNR Fisheries. Most recent: 2021-06-07 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Black Bullhead | 135.23 | 0.78 lb |
| Largemouth Bass | 45.42 | 0.96 lb |
| Bluegill | 37.93 | 0.25 lb |
| Pumpkinseed | 19.70 | 0.11 lb |
| Northern Pike | 13.54 | 2.93 lb |
| Walleye | 11.23 | 2.59 lb |
CPUE = catch per unit effort, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE = more abundant in standardized sampling.
Length Distributions
Number of fish caught at each inch class in the most recent survey that recorded lengths. Red dashed line marks an approximate trophy threshold for that species.
Black Bullhead
Largemouth Bass
Bluegill
Pumpkinseed
From the 2021-06-07 survey
Bass lake is a 292-acre eutrophic (fertile) lake located in south-central Otter Tail County. The town of Underwood, MN abuts the southeast shoreline of the lake. The immediate watershed is composed primarily of agricultural land interspersed with hardwood woodlots. The maximum depth is 36 feet; however, 47% of the…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Bass Lake. 3 reports on file.
- —Fisheries Lake Survey — BassFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — BassFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — BassPublic Water Access Sites · MN DNR LakeFinder
EPA Impairment Status
Bass Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN56-0569-02 · Official waterbody report · Matched by proximity (2.48 km)
Data Sources
Water quality data from the EPA Water Quality Portal
Impairment status from EPA ATTAINS 303(d) database
Grading methodology based on Metropolitan Council standards
Lake details from Minnesota DNR LakeFinder
Most recent sample: 2024-09-15
Monitoring stations: 1