Lancelot Lake Southwest Basin is a 250-acre mesotrophic lake in Gladwin County, Michigan. Water quality is graded B based on 2 sampling years through 2023. Water clarity is improving over recent sampling years. Limited fish-species data available. Public access is available with 2 public boat landings. Compared to the 8 other monitored lakes in Gladwin County, Lancelot Lake Southwest Basin ranks #4 for water quality.
Source: EPA Water Quality Portal sampling records, Michigan DNR, last sampled 2023-09-10. 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 10 ft. Chlorophyll-a: 6.2 µg/L. Trophic State Index: 46.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 10 ft | B |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | 6.2 µg/L | B |
| Trophic State Index (TSI) | 46 | Mesotrophic |
Moderate nutrients, good water quality
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 250 acres |
| Public Access | Yes |
Where to stay near Lancelot Lake Southwest Basin
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Fishing Lancelot Lake Southwest Basin
Water Quality Trend: → Stable
Based on 3 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +2.89 m/yr | 2 |
| Chlorophyll-a | ↓ Declining | +0.75 µg/L/yr | 3 |
Recreation & Access
Water Temperature
Lancelot Lake Southwest Basin averages about 73°F at the surface in summer, usually warmest in Aug (about 75°F) and coldest in May (about 62°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 256 field readings (2013–2023) via the EPA Water Quality Portal. See the full Lancelot Lake Southwest Basin water temperature breakdown →
Location
County Ranking
Ranked #4 of 9 lakes in Gladwin County
Cleaner Lakes Within 30 Miles
Lancelot Lake Southwest Basin holds Grade B. 2 nearby lakes hold higher grades.
- AIsland Lake Central Basin; Sherman TownshipGladwin County · 5.7 mi · Higher grade (B → A)
- ALancer Lake SoutheastGladwin County · 1.3 mi · Higher grade (B → A)
Nearby Lakes in Gladwin County
Explore Lancelot Lake Southwest Basin across LakeGrade
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Fish species and best lakes in Gladwin County
Species activity outlook by water temperature and season
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Moderate nutrients, good water quality
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Other Grade B Lakes in Michigan
Clare County · Clarity: 11 ft
Clare County · Clarity: 14 ft
Clare County · Clarity: 13.5 ft
Roscommon County · Clarity: 5 ft
Clare County · Clarity: 7.5 ft
Clare County · Clarity: 11.5 ft
Mesotrophic Lakes in Michigan
More records, surveys & data sources
Reservoir Info (USACE NID)
Lancelot Lake Southwest Basin is a man-made reservoir impounded by the Lake Lancelot Dam (completed 1976), built primarily for recreation on the Tributary to Sugar River; earth-type dam, 17 ft tall and 1,400 ft long.
- Surface area
- 250 ac
- Normal storage
- 1,950 ac-ft
- Max storage
- 2,100 ac-ft
- Drainage area
- 4.9 sq mi
- Hazard class
- Low
- Owner
- Gladwin County Drain Commissioner
Source: USACE National Inventory of Dams, NID ID MI00488 · Operator website · Matched by proximity (0.64 km)
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
Lake size & watershed from HydroLAKES (HydroSHEDS)
Grading methodology based on Metropolitan Council standards
Public boat-access points from the USGS National Boat Ramps inventory
Most recent sample: 2023-09-10
Monitoring stations: 1