Jamestown Dam
The Jamestown Dam is a rolled-earth dam spanning the James River in Stutsman County in the U.S. state of North Dakota, serving the primary purpose of flood control. It is north of the city of Jamestown, North Dakota. Built from April 1952 to September 1953, the dam measures 1,418 feet (432 m) long at the crest and 85 feet (26 m) high. It impounds the James River to form the Jamestown Reservoir. A small islet lies shortly upstream of the dam, where the James River previously split into two channels.
| Jamestown Dam & Reservoir | |
|---|---|
Jamestown Dam and Reservoir | |
Location of Jamestown Dam & Reservoir in North Dakota | |
| Country | United States |
| Location | Stutsman County, North Dakota, United States. Located near Jamestown. |
| Coordinates | 46.9333°N 98.710°W |
| Status | Operational |
| Construction began | 1952 |
| Opening date | 1953 |
| Construction cost | $1,941,857 |
| Owner(s) | United States Bureau of Reclamation |
| Dam and spillways | |
| Type of dam | Rolled-earth/Embankment |
| Impounds | James River |
| Height (thalweg) | 85 ft (26 m) |
| Length | 1,418 feet (432 m) |
| Width (base) | 215 ft (66 m) |
| Reservoir | |
| Creates | Jamestown Reservoir |
| Total capacity | 30,000 acre-feet (37,000,000 m3) (Normal pool); Up to 230,000 acre-feet (280,000,000 m3) (Maximum flood-storage pool) |
| Surface area | 2,095 acres (8.48 km2) (Normal pool); 13,250 acres (53.6 km2) (Maximum flood-storage pool) |
| Maximum water depth | 38 ft (12 m) |
| Website Jamestown Dam Project - U.S. Bureau of Reclamation | |
The dam and reservoir rest on a wide plain of shale where the James River cut a canyon up to 1 mile (1.6 km) wide and 100 feet (30 m) deep. The shale (called Pierre Shale) has a dark gray, bedded appearance, and is mostly claystone or siltstone. The valley also contains many traces of alluvium, mainly deposited during the last ice age when the area was heavily glaciated.