Red Willow Lake
Griggs County, North DakotaView mapDirections
ND DEQ publishes the water-quality measurements for Red Willow Lake. Here is what has been measured.
- 37 ft max depth
- Public access
- Limited data
Red Willow Lake in Griggs County, North Dakota has water-quality measurements published by ND DEQ, shown here as reported. Water clarity: 6.4 ft visibility. Chlorophyll-a (algae): 6.8 µg/L.
Red Willow Lake is a lake in Griggs County, North Dakota with an estimated average depth of about 37 feet. Overall water quality is declining over recent sampling years. Limited fish-species data available. Public access is available with 1 public boat landing.
Source: EPA Water Quality Portal sampling records, NDDEQ, last sampled 2025-10-23. Methodology: how these readings are compared.
What Red Willow Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Red Willow 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 Red Willow Lake
These are the measurements ND DEQ publishes for Red Willow Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Murky, only visible to about 6.4 ft. Chlorophyll-a 6.8 µg/L. TSI 50.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 6.4ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | No reading The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. | |
| Chlorophyll-a (algae) | 6.8µg/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. | 50 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Red Willow Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Red Willow Lake typically sits around 49°F at the surface in October. Summer average is about 67°F. Usually warmest in Aug (about 73°F) and coldest in Oct (about 49°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (49°F) to its warmest (73°F).
Typical surface water temperature by month, from 21 field readings (2020–2025) via the EPA Water Quality Portal. See the full Red Willow Lake water temperature breakdown →
Lake Details
Max depth
~37 ft est.
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 Red Willow Lake.
Lake Size & Watershed
Watershed (drainage) area
6 sq mi
HydroLAKES / HydroSHEDS
Surface area
114 acres
HydroLAKES / HydroSHEDS
Shoreline
2.2 mi
HydroLAKES / HydroSHEDS
Elevation
1,450 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
- Red Willow 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 Red Willow Lake
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Top-rated places to stay near Red Willow Lake
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Follow Red Willow Lake’s readings
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Fishing Red Willow Lake
Water quality readings over time
2 seasons of samples on record (2020–2025). Calling a direction takes at least 4 years of the same measurement.
Water clarity
Worsening2 years
Nearby Lakes in Griggs County
Frequently asked questions about Red Willow Lake
Where is Red Willow Lake?
- Red Willow Lake is a lake in Griggs 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 Red Willow Lake?
- Red Willow Lake in Griggs County, North Dakota has water-quality measurements published by ND DEQ, shown here as reported. Water clarity: 6.4 ft visibility. Chlorophyll-a (algae): 6.8 µg/L.
Is Red Willow 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 Red Willow Lake?
- Red Willow Lake typically sits around 49°F at the surface in October, from 21 EPA Water Quality Portal field readings (2020–2025). That is a typical value for the month, not a live reading.
How deep is Red Willow Lake?
- No published bathymetric survey covers Red Willow Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 37 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 Red Willow Lake?
- Red Willow Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Red Willow Lake. Public access is listed as yes.
Can I fish at Red Willow Lake?
- Red Willow 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.
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Where this data comes from
17 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- North Dakota Department Of Environmental Quality
21NDHDWQ_WQX17 samples · 2020–2025
Analytical methods
- Phosphorus by Colorimetry
- 447.0 ~ EPA; Chlorophyll a and b in phytoplankton by HPLC/UV
- 10200 H ~ Chlorophyll a-b-c Determination
- 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
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