Tolna Dam Lake is a 166-acre productive, nutrient-rich eutrophic lake in Nelson County, North Dakota with a maximum depth of 23 feet (10-foot average). Water quality is graded D based on 1 sampling years through 2025. The lake supports 5 documented fish species including Northern Pike, Walleye, and Yellow Perch. Public access is available with 1 public boat landing. Compared to the 8 other monitored lakes in Nelson County, Tolna Dam Lake ranks #5 for water quality.
Source: EPA Water Quality Portal sampling records, North Dakota DNR, last sampled 2025-10-13. Grade methodology: LakeGrade methodology.
Watch Tolna Dam Lake water quality
Subscribe for LakeQuality updates by email. No spam, unsubscribe anytime.
Swimming Safety
Swimming not recommended, poor water quality with high algae risk
Water Quality Grade: D, Poor
Murky, only visible to about 4.9 ft. Trophic State Index: 54.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 4.9 ft | D |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 54 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 22.7 ft |
| Average Depth | 10 ft |
| Surface Area | 166 acres |
| Shoreline Length | 5.2 mi |
| Public Access | Yes |
Where to stay near Tolna Dam Lake
Compare lakeside cabins, hotels, and vacation rentals near Tolna Dam Lake in Nelson County, North Dakota — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water.
Top-rated places to stay near Tolna Dam Lake
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a trip to Tolna Dam Lake?
Get lake water-quality report cards plus the best cabin & lodging deals near Tolna Dam Lake — straight to your inbox. No spam, unsubscribe anytime.
Planning a whole trip? See where to stay at North Dakota’s top lakes →
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Tolna Dam Lake
Recreation & Access
Water Temperature
Tolna Dam Lake averages about 67°F at the surface in summer, usually warmest in Aug (about 71°F) and coldest in Oct (about 55°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 12 field readings (2010–2025) via the EPA Water Quality Portal. See the full Tolna Dam Lake water temperature breakdown →
Location
County Ranking
Ranked #5 of 9 lakes in Nelson County
Cleaner Lakes Within 30 Miles
Tolna Dam Lake holds Grade D. 2 nearby lakes hold higher grades.
Nearby Lakes in Nelson County
Explore Tolna Dam Lake across LakeGrade
Fish species and top-graded lakes across North Dakota
Fish species and best lakes in Nelson County
Species activity outlook by water temperature and season
Top lakes and where to stay in the Devils Lake Region area
Where to stay at North Dakota's top lakes, each with its grade
High nutrients, frequent algae, reduced clarity
North Dakota's cleanest and most-polluted lakes, ranked
More North Dakota Lake Rankings
Other Grade D Lakes in North Dakota
Eutrophic Lakes in North Dakota
More records, surveys & data sources
Reservoir Info (USACE NID)
Tolna Dam Lake is a man-made reservoir impounded by the Tolna Dam 1 (completed 1936), built primarily for recreation on the Tolna Coulee; earth-type dam, 36 ft tall and 520 ft long.
- Surface area
- 166.3 ac
- Normal storage
- 2,027 ac-ft
- Max storage
- 3,080 ac-ft
- Drainage area
- 40 sq mi
- Hazard class
- Significant
- Owner
- Nelson County WRB
Source: USACE National Inventory of Dams, NID ID ND00027 · Operator website · Matched by proximity (0.27 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
Depth, fish, and access data from North Dakota Game & Fish
Public boat-access points from the USGS National Boat Ramps inventory
Most recent sample: 2025-10-13
Monitoring stations: 1