Tioga Dam Lake
Williams County, North Dakota83 acresView mapDirections
ND DEQ publishes the water-quality measurements for Tioga Dam Lake. Here is what has been measured.
- Eutrophic
- Public access
- Limited data
Tioga Dam Lake in Williams County, North Dakota has water-quality measurements published by ND DEQ, shown here as reported. Water clarity: 2.2 ft visibility. Phosphorus: 182 µg/L. Chlorophyll-a (algae): 20 µg/L. Surface area: 82.5 acres.
Tioga Dam Lake is a 83-acre productive, nutrient-rich eutrophic lake in Williams County, North Dakota. 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. Methodology: how these readings are compared.
What Tioga Dam Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
Swimming conditions
Readings onlyLimited data
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Tioga Dam Lake is safe to swim in today is a call for the North Dakota Department of Environmental Quality and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Tioga Dam Lake
These are the measurements ND DEQ publishes for Tioga Dam Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Very murky, less than 2.2 ft of visibility. Phosphorus 182 µg/L. Chlorophyll-a 20 µg/L. TSI 68.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 2.2ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 182µg/L | Measured, not scored The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. |
| Chlorophyll-a (algae) | 20µg/L | Measured, not scored The green pigment in algae — a direct measure of how much algae is in the water. |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 68 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Tioga Dam Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Surface area
83 acres
Public access
Yes
Listed by ND DEQ
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
Stays via Stay22
Stays near Tioga Dam Lake
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 readings cover nutrients and algae, not lodging. Cabins and rentals around Tioga Dam Lake are listed below.
Top-rated places to stay near Tioga Dam Lake
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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.
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. Its water-quality measurements are published by ND DEQ and shown on this page as reported.
What is the water quality of Tioga Dam Lake?
- Tioga Dam Lake in Williams County, North Dakota has water-quality measurements published by ND DEQ, shown here as reported. 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?
- Nutrient and algae readings are 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.
Can I fish at Tioga Dam Lake?
- Tioga Dam Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by North Dakota's fish and wildlife agency, so check its current regulations before you go.
Explore Tioga Dam Lake across LakeQuality
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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)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from 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