Gascoyne Lake
Bowman County, North DakotaView mapDirections
ND DEQ publishes the water-quality measurements for Gascoyne Lake. Here is what has been measured.
- Eutrophic
- 14 ft max depth
- Public access
- Limited data
Gascoyne Lake in Bowman County, North Dakota has water-quality measurements published by ND DEQ, shown here as reported. Water clarity: 1.3 ft visibility. Phosphorus: 90.5 µg/L. Chlorophyll-a (algae): 15.3 µg/L.
Gascoyne Lake is a 0-acre productive, nutrient-rich eutrophic lake in Bowman County, North Dakota with an estimated average depth of about 14 feet. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 3 other monitored lakes in Bowman County, Gascoyne Lake ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, NDDEQ, last sampled 2023-10-10. Methodology: how these readings are compared.
What Gascoyne 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 Gascoyne 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 Gascoyne Lake
These are the measurements ND DEQ publishes for Gascoyne 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 1.3 ft of visibility. Phosphorus 90.5 µg/L. Chlorophyll-a 15.3 µg/L. TSI 67.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 1.3ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 90.5µg/L | Measured, not scored The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. |
| Chlorophyll-a (algae) | 15.3µg/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. | 67 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Gascoyne Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Gascoyne Lake typically sits around 53°F at the surface in October. Summer average is about 66°F. Usually warmest in Jul (about 70°F) and coldest in Oct (about 53°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (53°F) to its warmest (70°F).
Typical surface water temperature by month, from 14 field readings (2023–2023) via the EPA Water Quality Portal. See the full Gascoyne Lake water temperature breakdown →
Lake Details
Max depth
~14 ft est.
Surface area
-
Public access
Yes
Listed by ND DEQ
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. North Dakota has not published bathymetry for Gascoyne Lake.
Lake Size & Watershed
Watershed (drainage) area
82 sq mi
HydroLAKES / HydroSHEDS
Surface area
188 acres
HydroLAKES / HydroSHEDS
Shoreline
3.1 mi
HydroLAKES / HydroSHEDS
Elevation
2,740 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
Recreation & Access
- Gascoyne LakePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Gascoyne Lake
Compare lakeside cabins, hotels, and vacation rentals near Gascoyne Lake in Bowman 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 Gascoyne Lake are listed below.
Top-rated places to stay near Gascoyne Lake
Prices for Oct 23–25, 4 adults. Change dates on the map below.
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 whole trip? See where to stay at North Dakota’s top lakes →
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Fishing Gascoyne Lake
Reservoir Info (USACE NID)
Gascoyne Lake is a man-made reservoir impounded by the Gascoyne Lake Dam (completed 1934), built primarily for recreation on the Buffalo Creek-TR; earth-type dam, 8 ft tall and 1,265 ft long.
- Surface area
- 0 ac
- Normal storage
- 1,300 ac-ft
- Max storage
- 1,691 ac-ft
- Drainage area
- 4 sq mi
- Hazard class
- Low
- Owner
- Bowman County WRB
Source: USACE National Inventory of Dams, NID ID ND00375 · Operator website
Regulated Pollution Sources Nearby
2 EPA-permitted facilities operate within about 5 miles of Gascoyne Lake under Clean Water Act (NPDES) discharge permits.
- Gascoyne Materials H&RGascoyne · 2.3 mi away · NPDES ND0026182
- American Colloid Co GascoyneScranton · 2.7 mi away · NPDES ND0026077
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 Bowman County
Frequently asked questions about Gascoyne Lake
Where is Gascoyne Lake?
- Gascoyne Lake is a lake in Bowman 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 Gascoyne Lake?
- Gascoyne Lake in Bowman County, North Dakota has water-quality measurements published by ND DEQ, shown here as reported. Water clarity: 1.3 ft visibility. Phosphorus: 90.5 µg/L. Chlorophyll-a (algae): 15.3 µg/L.
Is Gascoyne Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
What is the water temperature of Gascoyne Lake?
- Gascoyne Lake typically sits around 53°F at the surface in October, from 14 EPA Water Quality Portal field readings (2023–2023). That is a typical value for the month, not a live reading.
How deep is Gascoyne Lake?
- No published bathymetric survey covers Gascoyne Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 14 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
Are there boat ramps on Gascoyne Lake?
- Gascoyne Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Gascoyne Lake. Public access is listed as yes.
Can I fish at Gascoyne Lake?
- Gascoyne 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 Gascoyne Lake across LakeQuality
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Where this data comes from
21 measurements from 1 monitoring station, 2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- North Dakota Department Of Environmental Quality
21NDHDWQ_WQX21 samples · 2023
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)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Depth, fish, and access data from North Dakota Game & Fish
Named boat-access points from the USGS National Boat Ramps inventory