Lake Twenty East Basin is a 128-acre mesotrophic lake in Gladwin County, Michigan. Water quality is graded C based on 1 sampling years through 2023. Overall water quality is improving over recent sampling years. Compared to the 8 other monitored lakes in Gladwin County, Lake Twenty East Basin ranks #7 for water quality.
Source: EPA Water Quality Portal sampling records, Michigan DNR, last sampled 2023-09-14. Grade methodology: LakeGrade methodology.
Watch Lake Twenty East Basin water quality
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Swimming Safety
Generally safe for swimming, moderate water quality
Water Quality Grade: C, Fair
Moderate clarity, visible to about 9 ft. Trophic State Index: 45.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 9 ft | C |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 45 | Mesotrophic |
Moderate nutrients, good water quality
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 128 acres |
Where to stay near Lake Twenty East Basin
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Fishing Lake Twenty East Basin
Water Quality Trend: ↑ Improving
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +1.106 m/yr | 4 |
Water Temperature
Lake Twenty East Basin averages about 53°F at the surface in summer, usually warmest in Sep (about 55°F) and coldest in May (about 47°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 167 field readings (2014–2016) via the EPA Water Quality Portal. See the full Lake Twenty East Basin water temperature breakdown →
Location
County Ranking
Ranked #7 of 9 lakes in Gladwin County
Cleaner Lakes Within 30 Miles
Lake Twenty East Basin holds Grade C. 2 nearby lakes hold higher grades.
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Moderate nutrients, good water quality
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More records, surveys & data sources
Reservoir Info (USACE NID)
Lake Twenty East Basin is a man-made reservoir impounded by the Scottish Hills Lake Dam (completed 1974), built primarily for recreation on the Lake Twenty Outlet; earth-type dam, 14 ft tall and 200 ft long.
- Surface area
- 128 ac
- Normal storage
- 1,350 ac-ft
- Max storage
- 2,100 ac-ft
- Drainage area
- 3.6 sq mi
- Hazard class
- Low
- Owner
- Scottish Hills Condominium Assn
Source: USACE National Inventory of Dams, NID ID MI00656 · Operator website · Matched by proximity (0.75 km)
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth is a modeled estimate.
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Lake Twenty East Basin under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Gladwin WwtpGladwin · 4.6 mi away · NPDES MI0023001Recent violation
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
Data Sources
Water quality data from the EPA Water Quality Portal
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Grading methodology based on Metropolitan Council standards
Most recent sample: 2023-09-14
Monitoring stations: 1