Larimore Dam Lake
Grand Forks County, North Dakota72 acresView mapDirections
ND DEQ publishes the water-quality measurements for Larimore Dam Lake. Here is what has been measured.
- Eutrophic
- Impaired · Nutrients (phosphorus, nitrogen)
- 28 ft max depth
- Public access
Larimore Dam Lake in Grand Forks County, North Dakota has water-quality measurements published by ND DEQ, shown here as reported. Water clarity: 3 ft visibility. Phosphorus: 225 µg/L. Chlorophyll-a (algae): 13.3 µg/L. Surface area: 72 acres.
Larimore Dam Lake is a 72-acre productive, nutrient-rich eutrophic lake in Grand Forks County, North Dakota with an estimated average depth of about 28 feet. Overall water quality is improving over recent sampling years. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 1 other monitored lakes in Grand Forks County, Larimore Dam Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, NDDEQ, last sampled 2025-10-13. Methodology: how these readings are compared.
Larimore Dam Lake covers about 72 acres in Grand Forks County. It has one public boat landing. Vrbo is where to look for cabins and lake homes around Larimore Dam Lake, and Booking.com and Expedia search hotels near the lake for your dates.
What Larimore Dam Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
Swimming conditions
Readings onlyModerate algae
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. Larimore Dam Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
Whether Larimore 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 Larimore Dam Lake
These are the measurements ND DEQ publishes for Larimore 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 3 ft of visibility. Phosphorus 225 µg/L. Chlorophyll-a 13.3 µg/L. TSI 66.
| 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 | 225µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | 13.3µg/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. | 66 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Larimore Dam Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Larimore Dam Lake typically sits around 51°F at the surface in October. Summer average is about 65°F. Usually warmest in Aug (about 68°F) and coldest in Oct (about 51°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (51°F) to its warmest (68°F).
Typical surface water temperature by month, from 51 field readings (2020–2025) via the EPA Water Quality Portal. See the full Larimore Dam Lake water temperature breakdown →
Lake Details
Max depth
~28 ft est.
Surface area
72 acres
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 Larimore Dam Lake.
Lake Size & Watershed
Watershed (drainage) area
58 sq mi
HydroLAKES / HydroSHEDS
Shoreline
1.5 mi
HydroLAKES / HydroSHEDS
Elevation
1,063 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
- Larimore 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 Larimore Dam Lake
Compare lakeside cabins, hotels, and vacation rentals near Larimore Dam Lake in Grand Forks 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.
Top-rated places to stay near Larimore Dam Lake
Prices for Oct 23–25, 4 adults. Change dates on the map below.
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Fishing Larimore Dam Lake
Water Quality Trend: Improving
Based on 4 years of monitoring (2020–2025).
Water clarity
Worsening4 years
Phosphorus
Improving-102 µg/L/yr2 years
Chlorophyll-a
Improving-11.54 µg/L/yr3 years
Reservoir Info (USACE NID)
Larimore Dam Lake is a man-made reservoir impounded by the Upper Turtle River Flood Ret. 9 (completed 1979), built primarily for flood risk reduction on the South Branch Turtle River; earth-type dam, 71 ft tall and 1,040 ft long.
- Surface area
- 72 ac
- Normal storage
- 823 ac-ft
- Max storage
- 10,410 ac-ft
- Drainage area
- 64.9 sq mi
- Hazard class
- High
- Owner
- Grand Forks County WRB
All listed purposes: Flood Risk Reduction;Recreation.
Source: USACE National Inventory of Dams, NID ID ND00391 · Operator website
EPA Impairment Status
Larimore Dam Lake is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit ND-09020307-001-L_00 · Official waterbody report
Nearby Lakes in Grand Forks County
Frequently asked questions about Larimore Dam Lake
Where is Larimore Dam Lake?
- Larimore Dam Lake is a lake in Grand Forks 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 Larimore Dam Lake?
- Larimore Dam Lake in Grand Forks County, North Dakota has water-quality measurements published by ND DEQ, shown here as reported. Water clarity: 3 ft visibility. Phosphorus: 225 µg/L. Chlorophyll-a (algae): 13.3 µg/L. Surface area: 72 acres.
Is Larimore Dam Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Larimore Dam Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
What is the water temperature of Larimore Dam Lake?
- Larimore Dam Lake typically sits around 51°F at the surface in October, from 51 EPA Water Quality Portal field readings (2020–2025). That is a typical value for the month, not a live reading.
How deep is Larimore Dam Lake?
- No published bathymetric survey covers Larimore Dam Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 28 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate. The lake covers 72 acres.
Are there boat ramps on Larimore Dam Lake?
- Larimore Dam Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Larimore Dam. Public access is listed as yes.
Can I fish at Larimore Dam Lake?
- Larimore 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 Larimore Dam Lake across LakeQuality
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Where this data comes from
75 measurements from 3 monitoring stations, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- North Dakota Department Of Environmental Quality
21NDHDWQ_WQX75 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 (3)
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
Impairment status from EPA ATTAINS 303(d) database
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