Castle Rock Dam Lake is a 14-acre productive, nutrient-rich eutrophic lake in Hettinger County, North Dakota with a maximum depth of 14 feet (6-foot average). Water quality is graded D based on 2 sampling years through 2023. The lake supports 1 documented fish species including Rainbow Trout. Compared to the 2 other monitored lakes in Hettinger County, Castle Rock Dam Lake ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, North Dakota DNR, last sampled 2023-10-10. 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 3.8 ft. Chlorophyll-a: 24.3 µg/L. Trophic State Index: 60.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 3.8 ft | D |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | 24.3 µg/L | D |
| Trophic State Index (TSI) | 60 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 13.8 ft |
| Average Depth | 6 ft |
| Surface Area | 14 acres |
| Shoreline Length | 0.9 mi |
Where to stay near Castle Rock Dam Lake
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Fish Species
Click a species to see every graded lake where it is documented.
Fishing Castle Rock Dam Lake
Water Temperature
Castle Rock Dam Lake averages about 63°F at the surface in summer, usually warmest in Aug (about 63°F) and coldest in Oct (about 49°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 12 field readings (2023–2023) via the EPA Water Quality Portal. See the full Castle Rock Dam Lake water temperature breakdown →
Location
County Ranking
Ranked #3 of 3 lakes in Hettinger County
Cleaner Lakes Within 30 Miles
Castle Rock Dam Lake holds Grade D. 3 nearby lakes hold higher grades.
- BNorth Lemmon LakeAdams County · 25.3 mi · Two grade letters higher (D → B)
- CLarson LakeHettinger County · 8.3 mi · Higher grade (D → C)
- CIndian Creek Dam LakeHettinger County · 10.9 mi · Higher grade (D → C)
Nearby Lakes in Hettinger County
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High nutrients, frequent algae, reduced clarity
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Reservoir Info (USACE NID)
Castle Rock Dam Lake is a man-made reservoir impounded by the Castle Rock Dam (completed 1969), built primarily for recreation on the Cannonball River-TR; earth-type dam, 18 ft tall and 818 ft long.
- Surface area
- 14.2 ac
- Normal storage
- 75.1 ac-ft
- Max storage
- 184 ac-ft
- Drainage area
- 2.66 sq mi
- Hazard class
- Low
- Owner
- Louise & Larry Roemmich
Source: USACE National Inventory of Dams, NID ID ND00261 · Operator website
Data Sources
Water quality data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Depth, fish, and access data from North Dakota Game & Fish
Most recent sample: 2023-10-10
Monitoring stations: 1