Nygren Dam Lake
Morton County, North Dakota33 acresView mapDirections
ND DEQ publishes the water-quality measurements for Nygren Dam Lake. Here is what has been measured.
- Eutrophic
- Public access
Nygren Dam Lake in Morton County, North Dakota has water-quality measurements published by ND DEQ, shown here as reported. Water clarity: 2.6 ft visibility. Phosphorus: 73 µg/L. Chlorophyll-a (algae): 24.7 µg/L. Surface area: 33.1 acres.
Nygren Dam Lake is a 33-acre productive, nutrient-rich eutrophic lake in Morton County, North Dakota. Overall water quality is declining over recent sampling years. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 3 other monitored lakes in Morton County, Nygren Dam Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, NDDEQ, last sampled 2023-10-20. Methodology: how these readings are compared.
What Nygren Dam Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
Swimming conditions
Readings onlyAlgae risk
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 Nygren 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 Nygren Dam Lake
These are the measurements ND DEQ publishes for Nygren 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 2.6 ft of visibility. Phosphorus 73 µg/L. Chlorophyll-a 24.7 µg/L. TSI 64.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 2.6ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 73µg/L | Fair GoodFairPoor |
| Chlorophyll-a (algae) | 24.7µg/L | Poor GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 64 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Nygren Dam Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Nygren Dam Lake typically sits around 46°F at the surface in October. Summer average is about 64°F. Usually warmest in Jul (about 64°F) and coldest in Oct (about 46°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (46°F) to its warmest (64°F).
Typical surface water temperature by month, from 30 field readings (2011–2023) via the EPA Water Quality Portal. See the full Nygren Dam Lake water temperature breakdown →
Lake Details
Surface area
33 acres
Public access
Yes
Listed by ND DEQ
No bathymetric survey has been published for Nygren Dam Lake, so its depth is not documented here.
Recreation & Access
- Nygren 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 Nygren Dam Lake
Compare lakeside cabins, hotels, and vacation rentals near Nygren Dam Lake in Morton 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 Nygren Dam Lake are listed below.
Top-rated places to stay near Nygren Dam Lake
Prices for Oct 30–Nov 1, 4 adults. Change dates on the map below.
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Planning a whole trip? See where to stay at North Dakota’s top lakes →
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Fishing Nygren Dam Lake
Water quality readings over time
2 seasons of samples on record (2022–2023). Calling a direction takes at least 4 years of the same measurement.
Water clarity
Improving2 years
Phosphorus
Worsening+32.5 µg/L/yr2 years
Chlorophyll-a
Worsening+21.1 µg/L/yr2 years
Reservoir Info (USACE NID)
Nygren Dam Lake is a man-made reservoir impounded by the Nygren Dam (completed 1967), built primarily for recreation on the Heart River-TR; earth-type dam, 37 ft tall and 250 ft long.
- Surface area
- 33.1 ac
- Normal storage
- 92.3 ac-ft
- Max storage
- 193 ac-ft
- Drainage area
- 4 sq mi
- Hazard class
- Low
- Owner
- Morton County WRB & Hwy D
Source: USACE National Inventory of Dams, NID ID ND00200 · Operator website
Nearby Lakes in Morton County
Frequently asked questions about Nygren Dam Lake
Where is Nygren Dam Lake?
- Nygren Dam Lake is a lake in Morton 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 Nygren Dam Lake?
- Nygren Dam Lake in Morton County, North Dakota has water-quality measurements published by ND DEQ, shown here as reported. Water clarity: 2.6 ft visibility. Phosphorus: 73 µg/L. Chlorophyll-a (algae): 24.7 µg/L. Surface area: 33.1 acres.
Is Nygren Dam 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 Nygren Dam Lake?
- Nygren Dam Lake typically sits around 46°F at the surface in October, from 30 EPA Water Quality Portal field readings (2011–2023). That is a typical value for the month, not a live reading.
Are there boat ramps on Nygren Dam Lake?
- Nygren Dam Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Nygren Dam. Public access is listed as yes.
Can I fish at Nygren Dam Lake?
- Nygren 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 Nygren Dam Lake across LakeQuality
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Where this data comes from
50 measurements from 1 monitoring station, 2022–2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- North Dakota Department Of Environmental Quality
21NDHDWQ_WQX50 samples · 2022–2023
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
Depth, fish, and access data from North Dakota Game & Fish
Named boat-access points from the USGS National Boat Ramps inventory