Jamestown Reservoir
Stutsman County, North Dakota17,427 acresView mapDirections
ND DEQ publishes the water-quality measurements for Jamestown Reservoir. Here is what has been measured.
- Eutrophic
- Public access
Jamestown Reservoir in Stutsman County, North Dakota has water-quality measurements published by ND DEQ, shown here as reported. Water clarity: 7.2 ft visibility. Phosphorus: 527 µg/L. Chlorophyll-a (algae): 8.6 µg/L. Surface area: 17427 acres.
Jamestown Reservoir is a 17,427-acre productive, nutrient-rich eutrophic lake in Stutsman County, North Dakota. Limited fish-species data available. Public access is available with 4 public boat landings. Compared to the 2 other monitored lakes in Stutsman County, Jamestown Reservoir ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, NDDEQ, last sampled 2025-09-23. Methodology: how these readings are compared.
At about 17,000 acres, Jamestown Reservoir is large enough that where you stay decides which shore you see most of. It has 4 public boat landings, so a lakefront rental is not the only way to get a boat on the water. For a place on the water, look through cabin and lake-house rentals near Jamestown Reservoir on Vrbo. For a hotel or motel room, Booking.com and Expedia both search around the lake.
What Jamestown Reservoir is good for
From access and monitoring records, not editorial picks.
- Boat launch4 documented ramps
- Big water17,427 acres
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. Check local advisories before you swim.
Whether Jamestown Reservoir 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 Jamestown Reservoir
These are the measurements ND DEQ publishes for Jamestown Reservoir, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Moderate clarity, visible to about 7.2 ft. Phosphorus 527 µg/L. Chlorophyll-a 8.6 µg/L. TSI 65.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 7.2ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 527µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | 8.6µg/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. | 65 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Jamestown Reservoir
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Jamestown Reservoir typically sits around 54°F at the surface in October. Summer average is about 70°F. Usually warmest in Jul (about 74°F) and coldest in Oct (about 54°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (54°F) to its warmest (74°F).
Typical surface water temperature by month, from 369 field readings (2012–2025) via the EPA Water Quality Portal. See the full Jamestown Reservoir water temperature breakdown →
Lake Details
Surface area
17,427 acres
Public access
Yes
Listed by ND DEQ
No bathymetric survey has been published for Jamestown Reservoir, so its depth is not documented here.
Recreation & Access
- Jamestown ReservoirPublic
- Jamestown ReservoirPublic
- Jamestown ReservoirPublic
- Jamestown ReservoirPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Jamestown Reservoir
Compare lakeside cabins, hotels, and vacation rentals near Jamestown Reservoir in Stutsman 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 Jamestown Reservoir
Prices for Oct 23–25, 4 adults. Change dates on the map below.
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a trip? Cabins and lodging at Jamestown Reservoir → · more North Dakota lake trips
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Fishing Jamestown Reservoir
Reservoir Info (USACE NID)
Jamestown Reservoir is a man-made reservoir impounded by the Jamestown Dam (completed 1954), built primarily for flood risk reduction on the JAMES RIVER; earth-type dam, 110 ft tall and 1,418 ft long.
- Surface area
- 17,427 ac
- Normal storage
- 35,535 ac-ft
- Max storage
- 379,636 ac-ft
- Drainage area
- 1,573.65 sq mi
- Hazard class
- High
- Owner
- BUREAU OF RECLAMATION
All listed purposes: Flood Risk Reduction;Irrigation.
Source: USACE National Inventory of Dams, NID ID ND00151 · Operator website
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Jamestown Reservoir under Clean Water Act (NPDES) discharge permits, including 1 classified by the EPA as major discharger. 1 facility has a reported Clean Water Act violation in the past three years.
- Jamestown City OfJamestown · 3.9 mi away · NPDES ND0023370MajorRecent violation
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 Stutsman County
Frequently asked questions about Jamestown Reservoir
Where is Jamestown Reservoir?
- Jamestown Reservoir is a lake in Stutsman 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 Jamestown Reservoir?
- Jamestown Reservoir in Stutsman County, North Dakota has water-quality measurements published by ND DEQ, shown here as reported. Water clarity: 7.2 ft visibility. Phosphorus: 527 µg/L. Chlorophyll-a (algae): 8.6 µg/L. Surface area: 17427 acres.
Is Jamestown Reservoir 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 Jamestown Reservoir?
- Jamestown Reservoir typically sits around 54°F at the surface in October, from 369 EPA Water Quality Portal field readings (2012–2025). That is a typical value for the month, not a live reading.
Are there boat ramps on Jamestown Reservoir?
- Jamestown Reservoir has 4 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Jamestown Reservoir, Jamestown Reservoir, Jamestown Reservoir, Jamestown Reservoir. Public access is listed as yes.
Can I fish at Jamestown Reservoir?
- Jamestown Reservoir has 4 documented boat landings 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 Jamestown Reservoir across LakeQuality
Depth, room, public access, and the state wake-sport rules
Species activity outlook by water temperature and season
Where to stay at North Dakota's top lakes, each with its readings
North Dakota's cleanest lakes, ranked on agency measurements
More lakes in North Dakota
Other Lakes in North Dakota
Eutrophic Lakes in North Dakota
Where this data comes from
232 measurements from 4 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_WQX217 samples · 2021–2025 - USGS North Dakota Water Science Center
USGS-ND15 samples · 2020–2023
Analytical methods
- P, wu, WCA, persulfate CF color
- Plant pigments, sonication & 445
- 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 (4)
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
Named boat-access points from the USGS National Boat Ramps inventory