Jamestown Dam

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°56′00″N 98°42′36″W / 46.9333°N 98.710°W / 46.9333; -98.710
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)[1]
Maximum water depth	38 ft (12 m)
Website Jamestown Dam Project - U.S. Bureau of Reclamation

The Jamestown Dam^[2] 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.^[3] 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.

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.