Froelich Dam Lake is a 175-acre productive, nutrient-rich eutrophic lake in Sioux County, North Dakota with a maximum depth of 34 feet (12-foot average). Water quality is graded D based on 2 sampling years through 2023. The lake supports 6 documented fish species including Northern Pike, Walleye, and Yellow Perch. Public access is available with 1 public boat landing.
Source: EPA Water Quality Portal sampling records, North Dakota DNR, last sampled 2023-10-20. Grade methodology: LakeGrade methodology.
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Swimming Safety
Swimming not recommended, poor water quality with high algae risk
Water Quality Grade: D, Poor
Murky, only visible to about 3.9 ft. Chlorophyll-a: 37.5 µg/L. Trophic State Index: 62.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 3.9 ft | D |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | 37.5 µg/L | F |
| Trophic State Index (TSI) | 62 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 34.2 ft |
| Average Depth | 11.5 ft |
| Surface Area | 175 acres |
| Shoreline Length | 8.1 mi |
| Public Access | Yes |
Where to stay near Froelich Dam Lake
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Fish Species
Click a species to see every graded lake where it is documented.
Fishing Froelich Dam Lake
Recreation & Access
Water Temperature
Froelich Dam Lake averages about 69°F at the surface in summer, usually warmest in Jul (about 73°F) and coldest in Oct (about 48°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 67 field readings (2017–2023) via the EPA Water Quality Portal. See the full Froelich Dam Lake water temperature breakdown →
Location
County Ranking
Ranked #1 of 1 lakes in Sioux County
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Species activity outlook by water temperature and season
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High nutrients, frequent algae, reduced clarity
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More records, surveys & data sources
Reservoir Info (USACE NID)
Froelich Dam Lake is a man-made reservoir impounded by the Froelich Dam (completed 1962), built primarily for recreation on the Porcupine Creek-TR; earth-type dam, 46 ft tall and 821 ft long.
- Surface area
- 175 ac
- Normal storage
- 2,271.3 ac-ft
- Max storage
- 4,212.9 ac-ft
- Drainage area
- 68.3 sq mi
- Hazard class
- Low
- Owner
- ND Game & Fish
All listed purposes: Recreation;Fire Protection, Stock, Or Small Fish Pond.
Source: USACE National Inventory of Dams, NID ID ND00025 · Operator website
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
Depth, fish, and access data from North Dakota Game & Fish
Public boat-access points from the USGS National Boat Ramps inventory
Most recent sample: 2023-10-20
Monitoring stations: 1