Belourt Outlet Lake
Rolette County, North Dakota827 acresView mapDirections
ND DEQ publishes the water-quality measurements for Belourt Outlet Lake. Here is what has been measured.
- Eutrophic
Belourt Outlet Lake in Rolette County, North Dakota has water-quality measurements published by ND DEQ, shown here as reported. Water clarity: 3 ft visibility. Phosphorus: 28 µg/L. Chlorophyll-a (algae): 12.5 µg/L. Surface area: 827 acres.
Belourt Outlet Lake is a 827-acre productive, nutrient-rich eutrophic lake in Rolette County, North Dakota. Overall water quality is declining over recent sampling years. Compared to the 5 other monitored lakes in Rolette County, Belourt Outlet Lake ranks #4 for water quality.
Source: EPA Water Quality Portal sampling records, NDDEQ, last sampled 2025-09-16. Methodology: how these readings are compared.
Swimming conditions
Readings onlyBacteria tested: low
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.
Based on E. coli testing, Belourt Outlet Lake never exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 0% of 9 samples across 3 seasons.
This is a historical summary of past testing, not a current condition — bacteria levels change quickly, especially after rain. Always check North Dakota’s current beach and health-department advisories before swimming.
Whether Belourt Outlet 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 Belourt Outlet Lake
These are the measurements ND DEQ publishes for Belourt Outlet 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 3 ft of visibility. Phosphorus 28 µg/L. Chlorophyll-a 12.5 µg/L. TSI 56.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 3ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 28µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 12.5µg/L | Good GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 56 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Belourt Outlet Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Belourt Outlet Lake typically sits around 61°F at the surface in September. Summer average is about 70°F. Usually warmest in Jul (about 73°F) and coldest in May (about 55°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (55°F) to its warmest (73°F).
Typical surface water temperature by month, from 147 field readings (2010–2025) via the EPA Water Quality Portal. See the full Belourt Outlet Lake water temperature breakdown →
Lake Details
Surface area
827 acres
No bathymetric survey has been published for Belourt Outlet Lake, so its depth is not documented here.
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Fishing Belourt Outlet Lake
Water Quality Trend: Worsening
Based on 5 years of monitoring (2021–2025).
Water clarity
Improving5 years
Phosphorus
Worsening+3.25 µg/L/yr5 years
Chlorophyll-a
Worsening+0.3 µg/L/yr4 years
Reservoir Info (USACE NID)
Belourt Outlet Lake is a man-made reservoir impounded by the Belcourt Lake (completed 1930), built primarily for recreation on the Ox Creek; earth-type dam, 13 ft tall and 700 ft long.
- Surface area
- 827 ac
- Normal storage
- 5,651 ac-ft
- Max storage
- 9,159 ac-ft
- Drainage area
- 28.4 sq mi
- Hazard class
- High
- Owner
- BIA
All listed purposes: Recreation;Fish and Wildlife Pond;Water Supply.
Source: USACE National Inventory of Dams, NID ID ND00535 · Operator website · Matched by proximity (0.06 km)
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Belourt Outlet Lake under Clean Water Act (NPDES) discharge permits.
- Belcourt Public UtilitiesBelcourt · 2.8 mi away · NPDES ND0023647
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 Rolette County
Frequently asked questions about Belourt Outlet Lake
Where is Belourt Outlet Lake?
- Belourt Outlet Lake is a lake in Rolette 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 Belourt Outlet Lake?
- Belourt Outlet Lake in Rolette County, North Dakota has water-quality measurements published by ND DEQ, shown here as reported. Water clarity: 3 ft visibility. Phosphorus: 28 µg/L. Chlorophyll-a (algae): 12.5 µg/L. Surface area: 827 acres.
Is Belourt Outlet Lake safe to swim in?
- Based on E. coli testing, Belourt Outlet Lake never exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 0% of 9 samples across 3 seasons. That is a historical summary of past bacteria testing, not a current reading and not a swimming clearance. Bacteria levels can spike quickly after heavy rain, so whether Belourt Outlet Lake is safe to swim in today is a call for North Dakota's water agency and the county health department; check their current beach advisories before you swim.
What is the water temperature of Belourt Outlet Lake?
- Belourt Outlet Lake typically sits around 61°F at the surface in September, from 147 EPA Water Quality Portal field readings (2010–2025). That is a typical value for the month, not a live reading.
Explore Belourt Outlet Lake across LakeQuality
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Species activity outlook by water temperature and season
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Where this data comes from
217 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Turtle Mountain Environmental Office (Tribal)
TURTLEMT217 samples · 2020–2025
Analytical methods
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
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