Epping-Springbrook Dam-Deepest Lake
Williams County, North Dakota148 acresView mapDirections
Nutrients and algae run above the regional average.
- Eutrophic
- #5 of 6 in the county
- Public access
Epping-Springbrook Dam-Deepest Lake in Williams County, North Dakota has a water quality grade of D (Nutrient-rich). Water clarity: 4.9 ft visibility. Phosphorus: 689.5 µg/L. Chlorophyll-a (algae): 20.4 µg/L. Surface area: 148 acres.
- Clarity
- 4.9 ft
- Typical in September
- 58°F
- Area
- 148 acres
- Type
- Eutrophic
- Trend
- ↑ Improving
- Public access
- Yes
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Compare lakeside cabins, hotels, and vacation rentals near Epping-Springbrook Dam-Deepest Lake in Williams 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 grade measures nutrients and algae, not lodging — cabins and rentals around Epping-Springbrook Dam-Deepest Lake are listed below.
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Epping-Springbrook Dam-Deepest Lake is a 148-acre productive, nutrient-rich eutrophic lake in Williams County, North Dakota. Water quality is graded D based on 3 sampling years through 2025. 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 5 other monitored lakes in Williams County, Epping-Springbrook Dam-Deepest Lake ranks #5 for water quality.
Source: EPA Water Quality Portal sampling records, NDDEQ, last sampled 2025-10-28. Grade methodology: LakeQuality methodology.
What Epping-Springbrook Dam-Deepest Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
Swimming Safety
Grade onlyAlgae risk
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
The D is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
Water Quality Grade: D (Nutrient-rich)
Murky, only visible to about 4.9 ft. Phosphorus 689.5 µg/L. Chlorophyll-a 20.4 µg/L. TSI 71. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 4.9 ft | Not graded |
| Phosphorus | 689.5 µg/L | Poor |
| Chlorophyll-a (Algae) | 20.4 µg/L | Poor |
| Trophic State Index (TSI) | 71 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Water Temperature
Epping-Springbrook Dam-Deepest Lake typically sits around 58°F at the surface in September. Summer average is about 65°F. Usually warmest in Aug (about 66°F) and coldest in Oct (about 45°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 82 field readings (2011–2025) via the EPA Water Quality Portal. See the full Epping-Springbrook Dam-Deepest Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 148 acres |
| Public Access | Yes |
No bathymetric survey has been published for Epping-Springbrook Dam-Deepest Lake, so its depth is not documented here.
Recreation & Access
- Epping-Springbrook DamPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fishing Epping-Springbrook Dam-Deepest Lake
Water Quality Trend: ↑ Improving
Based on 3 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.35 m/yr | 3 |
| Phosphorus | ↑ Improving | -435 µg/L/yr | 2 |
| Chlorophyll-a | ↑ Improving | -17.8 µg/L/yr | 2 |
Reservoir Info (USACE NID)
Epping-Springbrook Dam-Deepest Lake is a man-made reservoir impounded by the Epping Dam (completed 1935), built primarily for recreation on the Stony Creek; earth-type dam, 56 ft tall and 1,000 ft long.
- Surface area
- 148 ac
- Normal storage
- 1,560 ac-ft
- Max storage
- 3,890 ac-ft
- Drainage area
- 72.9 sq mi
- Hazard class
- Significant
- Owner
- Williams County WRB
Source: USACE National Inventory of Dams, NID ID ND00249 · Operator website · Matched by proximity (0.17 km)
County Ranking
Ranked #5 of 6 lakes in Williams County
Nearby Lakes With Higher Grades
Epping-Springbrook Dam-Deepest Lake holds Grade D. One nearby lake has a higher nutrient-and-algae grade — useful for a swim day, not a reason to skip lodging here.
See full comparison →Nearby Lakes in Williams County
Frequently asked questions about Epping-Springbrook Dam-Deepest Lake
Where is Epping-Springbrook Dam-Deepest Lake?
- Epping-Springbrook Dam-Deepest Lake is a lake in Williams County, North Dakota. LakeQuality grades it D for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Epping-Springbrook Dam-Deepest Lake?
- Epping-Springbrook Dam-Deepest Lake in Williams County, North Dakota has a water quality grade of D (Nutrient-rich). Water clarity: 4.9 ft visibility. Phosphorus: 689.5 µg/L. Chlorophyll-a (algae): 20.4 µg/L. Surface area: 148 acres.
Is Epping-Springbrook Dam-Deepest Lake safe to swim in?
- The D is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
What is the water temperature of Epping-Springbrook Dam-Deepest Lake?
- Epping-Springbrook Dam-Deepest Lake typically sits around 58°F at the surface in September, from 82 EPA Water Quality Portal field readings (2011–2025). That is a typical value for the month, not a live reading.
Are there boat ramps on Epping-Springbrook Dam-Deepest Lake?
- Epping-Springbrook Dam-Deepest Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Epping-Springbrook Dam. Public access is listed as yes.
Explore Epping-Springbrook Dam-Deepest Lake across LakeQuality
Species activity outlook by water temperature and season
Where to stay at North Dakota's top lakes, each with its grade
High nutrients, frequent algae, reduced clarity
North Dakota's cleanest and most-polluted lakes, ranked
More North Dakota Lake Rankings
Other Grade D Lakes in North Dakota
Eutrophic Lakes in North Dakota
Where this data comes from
177 measurements from 1 monitoring station, 2023–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- North Dakota Department Of Environmental Quality
21NDHDWQ_WQX177 samples · 2023–2025
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)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated 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