Tioga Dam Lake
Williams County, North Dakota83 acresView mapDirections
Nutrients and algae run above the regional average.
- Eutrophic
- #6 of 6 in the county
- Public access
- Limited data
Tioga Dam Lake in Williams County, North Dakota has a water quality grade of D (Nutrient-rich). Water clarity: 2.2 ft visibility. Phosphorus: 182 µg/L. Chlorophyll-a (algae): 20 µg/L. Surface area: 82.5 acres.
- Clarity
- 2.2 ft
- Area
- 83 acres
- Type
- Eutrophic
- Public access
- Yes
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Compare lakeside cabins, hotels, and vacation rentals near Tioga Dam Lake in Williams 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. The water-quality grade measures nutrients and algae, not lodging — cabins and rentals around Tioga Dam Lake are listed below.
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Tioga Dam Lake is a 83-acre productive, nutrient-rich eutrophic lake in Williams County, North Dakota. Water quality is graded D based on 1 sampling years through 2024. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 5 other monitored lakes in Williams County, Tioga Dam Lake ranks #6 for water quality.
Source: EPA Water Quality Portal sampling records, NDDEQ, last sampled 2024-10-03. Grade methodology: LakeQuality methodology.
What Tioga Dam Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
Swimming Safety
Grade onlyLimited data
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
The D is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
Water Quality Grade: D (Nutrient-rich)
Very murky, less than 2.2 ft of visibility. Phosphorus 182 µg/L. Chlorophyll-a 20 µg/L. TSI 68. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 2.2 ft | Not graded |
| Phosphorus | 182 µg/L | Not graded |
| Chlorophyll-a (Algae) | 20 µg/L | Not graded |
| Trophic State Index (TSI) | 68 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 83 acres |
| Public Access | Yes |
No bathymetric survey has been published for Tioga Dam Lake, so its depth is not documented here.
Recreation & Access
- Tioga DamPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fishing Tioga Dam Lake
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.
County Ranking
Ranked #6 of 6 lakes in Williams County
Nearby Lakes in Williams County
Frequently asked questions about Tioga Dam Lake
Where is Tioga Dam Lake?
- Tioga Dam Lake is a lake in Williams County, North Dakota. LakeQuality grades it D for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Tioga Dam Lake?
- Tioga Dam Lake in Williams County, North Dakota has a water quality grade of D (Nutrient-rich). Water clarity: 2.2 ft visibility. Phosphorus: 182 µg/L. Chlorophyll-a (algae): 20 µg/L. Surface area: 82.5 acres.
Is Tioga Dam Lake safe to swim in?
- The D is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
Are there boat ramps on Tioga Dam Lake?
- Tioga Dam Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Tioga Dam. Public access is listed as yes.
Explore Tioga Dam Lake across LakeQuality
Species activity outlook by water temperature and season
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
Where this data comes from
20 measurements from 1 monitoring station, 2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- North Dakota Department Of Environmental Quality
21NDHDWQ_WQX20 samples · 2024
Analytical methods
- Phosphorus by Colorimetry
- 447.0 ~ EPA; Chlorophyll a and b in phytoplankton by HPLC/UV
- 4500 NO3 E ~ Nitrate in Water- Cadmium Reduction
Monitoring station identifiers (1)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.
Other records on this page
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Depth, fish, and access data from North Dakota Game & Fish
Named boat-access points from the USGS National Boat Ramps inventory