Little Portage Lake is a mesotrophic lake in Washtenaw County, Michigan. Water quality is graded B based on 1 sampling years through 2022. Overall water quality is improving over recent sampling years. The lake supports 1 documented fish species including Grass pickerel. Compared to the 16 other monitored lakes in Washtenaw County, Little Portage Lake ranks #8 for water quality.
Source: EPA Water Quality Portal sampling records, Michigan DNR, last sampled 2022-08-14. Grade methodology: LakeGrade methodology.
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Swimming Safety
Good for swimming, clear water with low algae levels
Water Quality Grade: B, Good
Good clarity, visible to about 12 ft. Trophic State Index: 41.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 12 ft | B |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 41 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Little Portage Lake
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Fish Species
Click a species to see every graded lake where it is documented.
Fishing Little Portage Lake
Water Quality Trend: ↑ Improving
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.916 m/yr | 4 |
Location & Depth Map
Free interactive depth-contour map of Little Portage Lake, reaching a maximum surveyed depth of 42 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Michigan DNR.
County Ranking
Ranked #8 of 17 lakes in Washtenaw County
Cleaner Lakes Within 30 Miles
Little Portage Lake holds Grade B. One nearby lake has a higher grade.
Nearby Lakes in Washtenaw County
Explore Little Portage Lake across LakeGrade
Fish species and top-graded lakes across Michigan
Fish species and best lakes in Washtenaw County
Species activity outlook by water temperature and season
Where to stay at Michigan's top lakes, each with its grade
Moderate nutrients, good water quality
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Other Grade B Lakes in Michigan
Livingston County · Clarity: 13 ft
Livingston County · Clarity: 10.5 ft
Livingston County · Clarity: 10.5 ft
Livingston County · Clarity: 10.5 ft
Livingston County · Clarity: 9.5 ft
Livingston County · Clarity: 8.5 ft
Mesotrophic Lakes in Michigan
More records, surveys & data sources
EPA Impairment Status
Little Portage Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MI040900050307-23 · Official waterbody report
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth is a modeled estimate.
Data Sources
Water quality data from the EPA Water Quality Portal
Impairment status from EPA ATTAINS 303(d) database
Lake size & watershed from HydroLAKES (HydroSHEDS)
Grading methodology based on Metropolitan Council standards
Most recent sample: 2022-08-14
Monitoring stations: 1