Jensen Lake
Dakota County, MinnesotaEutrophic
The LakeGrade rubric puts Jensen Lake at a C: clarity at 5.0 ft, 24 µg/L of phosphorus, and a TSI of 52 signal an intermediate trophic state. Secchi readings are the weakest of the scored parameters, suggesting suspended sediment or algal biomass dominates the optical signal.
At a TSI of 52, Jensen 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. Among the 36 graded lakes in Dakota County, Jensen Lake sits at rank 11, above the county median.
No invasive species are currently listed at Jensen Lake — the lake remains off the Minnesota infested-waters roster. The state fisheries records do not list documented species for Jensen 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. Ice-out has been recorded 9 times at Jensen Lake, with a median around Apr 4. The grade is supported by multiple sampling years from Minnesota PCA volunteers and partner agencies, giving the letter a reasonably stable foundation.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-10-19. 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 ft. Phosphorus level: 23.5 µg/L. Chlorophyll-a: 9 µg/L. Trophic State Index: 52.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 5 ft | D |
| Phosphorus | 23.5 µg/L | B |
| Chlorophyll-a (Algae) | 9 µg/L | B |
| Trophic State Index (TSI) | 52 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Water Quality Trend: ↓ Declining
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.769 m/yr | 5 |
| Phosphorus | ↑ Improving | -15.45 µg/L/yr | 5 |
| Chlorophyll-a | ↓ Declining | +1.4 µg/L/yr | 2 |
Ice Season
Historical ice data from Minnesota DNR (10 observations).
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2016-03-13 (2016) | 1996-04-19 (1996) |
| Ice-In | 2023-11-24 (2023) | 2023-11-24 (2023) |
Most recent ice-out: 2023-04-14
Location
County Ranking
Ranked #11 of 36 lakes in Dakota County
Cleaner Lakes Within 30 Miles
Jensen Lake holds Grade C. 4 nearby lakes hold higher grades.
- AHolland LakeDakota County · mi · Two grade letters higher (C → A)
- BO'Brien LakeDakota County · mi · Higher grade (C → B)
- BSchultz LakeDakota County · mi · Higher grade (C → B)
- BCarlson LakeDakota County · mi · Higher grade (C → B)
Nearby Lakes in Dakota County
More Minnesota Lake Rankings
State Parks Near Jensen Lake
Other Grade C 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 Jensen Lake. 1 report on file.
- —Public Water Access Sites — JensenPublic Water Access Sites · MN DNR LakeFinder
EPA Impairment Status
Jensen 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 MN19-0023-00 · Official waterbody report · Matched by proximity (2.2 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
Ice data from Minnesota DNR Climate
Most recent sample: 2024-10-19
Monitoring stations: 2