Tioga Dam Lake is a 83-acre productive, nutrient-rich eutrophic lake in Williams County, North Dakota with a maximum depth of 29 feet (11-foot average). Water quality is graded D based on 2 sampling years through 2024. The lake supports 3 documented fish species including Northern Pike, Yellow Perch, and Bluegill. Public access is available with 1 public boat landing. Compared to the 8 other monitored lakes in Williams County, Tioga Dam Lake ranks #9 for water quality.
Source: EPA Water Quality Portal sampling records, North Dakota DNR, last sampled 2024-10-03. 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
Very murky, less than 2.2 ft of visibility. Chlorophyll-a: 20 µg/L. Trophic State Index: 63.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 2.2 ft | F |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | 20 µg/L | D |
| Trophic State Index (TSI) | 63 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 28.9 ft |
| Average Depth | 11.1 ft |
| Surface Area | 83 acres |
| Shoreline Length | 3 mi |
| Public Access | Yes |
Where to stay near Tioga Dam Lake
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Fish Species
Click a species to see every graded lake where it is documented.
Fishing Tioga Dam Lake
Recreation & Access
Location
County Ranking
Ranked #9 of 9 lakes in Williams County
Cleaner Lakes Within 30 Miles
Tioga Dam Lake holds Grade D. 5 nearby lakes hold higher grades.
- BKota Ray Dam LakeWilliams County · 15.1 mi · Two grade letters higher (D → B)
- CWhite Earth Dam LakeMountrail County · 9.3 mi · Higher grade (D → C)
- CPowers LakeMountrail County · 17.4 mi · Higher grade (D → C)
- CMcleod ReservoirWilliams County · 11.9 mi · Higher grade (D → C)
- CPowers Lake Dredge SiteMountrail County · 17.2 mi · Higher grade (D → C)
Nearby Lakes in Williams County
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High nutrients, frequent algae, reduced clarity
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More records, surveys & data sources
Reservoir Info (USACE NID)
Tioga Dam Lake is a man-made reservoir impounded by the Tioga Dam (completed 1963), built primarily for recreation on the White Earth River-TR; earth-type dam, 39 ft tall and 1,660 ft long.
- Surface area
- 82.5 ac
- Normal storage
- 820 ac-ft
- Max storage
- 1,630 ac-ft
- Drainage area
- 5.86 sq mi
- Hazard class
- High
- Owner
- City of Tioga
All listed purposes: Recreation;Flood Risk Reduction.
Source: USACE National Inventory of Dams, NID ID ND00026 · Operator website
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Tioga Dam Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Hess Tioga Gas Plant LlcTioga · 1.2 mi away · NPDES ND0025836Recent 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)
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: 2024-10-03
Monitoring stations: 1