E. A. Patterson Lake is a 2,158-acre productive, nutrient-rich eutrophic lake in Stark County, North Dakota with a maximum depth of 18 feet (10-foot average). Water quality is graded D based on 3 sampling years through 2023. Water clarity is declining over recent sampling years. The lake supports 6 documented fish species including Rainbow Trout, Channel Catfish, and Largemouth Bass. Public access is available with 1 public boat landing. Compared to the 2 other monitored lakes in Stark County, E. A. Patterson Lake ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, North Dakota DNR, last sampled 2023-07-25. Grade methodology: LakeGrade methodology.
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Swimming Safety
Swimming not recommended, poor water quality with high algae risk
Water Quality Grade: D, Poor
Murky, only visible to about 5.3 ft. Phosphorus level: 262.5 µg/L. Chlorophyll-a: 15.9 µg/L. Trophic State Index: 65.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 5.3 ft | D |
| Phosphorus | 262.5 µg/L | F |
| Chlorophyll-a (Algae) | 15.9 µg/L | C |
| Trophic State Index (TSI) | 65 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 18.4 ft |
| Average Depth | 9.8 ft |
| Surface Area | 2,158 acres |
| Shoreline Length | 0.7 mi |
| Public Access | Yes |
Where to stay near E. A. Patterson Lake
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Fish Species
Click a species to see every graded lake where it is documented.
Fishing E. A. Patterson Lake
Water Quality Trend: → Stable
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -6.33 m/yr | 4 |
| Phosphorus | → Stable | -1.8 µg/L/yr | 4 |
| Chlorophyll-a | ↑ Improving | -1.24 µg/L/yr | 4 |
Recreation & Access
Water Temperature
E. A. Patterson Lake averages about 68°F at the surface in summer, usually warmest in Jul (about 71°F) and coldest in Feb (about 36°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 355 field readings (2010–2023) via the EPA Water Quality Portal. See the full E. A. Patterson Lake water temperature breakdown →
Location
County Ranking
Ranked #3 of 3 lakes in Stark County
Cleaner Lakes Within 30 Miles
E. A. Patterson Lake holds Grade D. One nearby lake has a higher grade.
See full comparison →Nearby Lakes in Stark County
Explore E. A. Patterson Lake across LakeGrade
Fish species and top-graded lakes across North Dakota
Fish species and best lakes in Stark County
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
Hettinger County · Clarity: 3.8 ft
Bowman County · Clarity: 1.3 ft
Grant County · Clarity: 2.7 ft
Golden Valley County · Clarity: 1.5 ft
Mountrail County · Clarity: 1.1 ft
Williams County · Clarity: 4.9 ft
Eutrophic Lakes in North Dakota
Compare E. A. Patterson Lake With Nearby Lakes
More records, surveys & data sources
Reservoir Info (USACE NID)
E. A. Patterson Lake is a man-made reservoir impounded by the Dickinson Dam (completed 1950), built primarily for irrigation on the HEART RIVER; earth-type dam, 65 ft tall and 2,275 ft long.
- Surface area
- 2,158 ac
- Normal storage
- 8,612 ac-ft
- Max storage
- 26,462 ac-ft
- Drainage area
- 401.42 sq mi
- Hazard class
- High
- Owner
- BUREAU OF RECLAMATION
All listed purposes: Irrigation;Water Supply.
Source: USACE National Inventory of Dams, NID ID ND00148 · Operator website · Matched by proximity (0.29 km)
EPA Impairment Status
E. A. Patterson 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-10130202-002-L_00 · Official waterbody report · Matched by proximity (2.7 km)
Regulated Pollution Sources Nearby
2 EPA-permitted facilities operate within about 5 miles of E. A. Patterson Lake 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.
- Dickinson City OfDickinson · 2.2 mi away · NPDES ND0023175MajorRecent violation
- Southwest Water AuthorityDickinson · 1.3 mi away · NPDES ND0023183
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.
Data Sources
Water quality data from the EPA Water Quality Portal
Impairment status from EPA ATTAINS 303(d) database
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Grading methodology based on Metropolitan Council standards
Depth, fish, and access data from North Dakota Game & Fish
Public boat-access points from the USGS National Boat Ramps inventory
Most recent sample: 2023-07-25
Monitoring stations: 1