The Jamestown Dam is a rolled-earth

dam A dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use, aqua ...

spanning the

James River The James River is a river in Virginia that begins in the Appalachian Mountains and flows from the confluence of the Cowpasture and Jackson Rivers in Botetourt County U.S. Geological Survey. National Hydrography Dataset high-resolution flowli ...

in Stutsman County in the U.S. state of

North Dakota North Dakota ( ) is a U.S. state in the Upper Midwest, named after the indigenous Dakota people, Dakota and Sioux peoples. It is bordered by the Canadian provinces of Saskatchewan and Manitoba to the north and by the U.S. states of Minneso ...

, serving the primary purpose of

flood control Flood management or flood control are methods used to reduce or prevent the detrimental effects of flood waters. Flooding can be caused by a mix of both natural processes, such as extreme weather upstream, and human changes to waterbodies and ru ...

. It is north of the city of

Jamestown, North Dakota Jamestown is a city in and the county seat of Stutsman County, North Dakota, United States. The population was 15,849 at the 2020 United States census, 2020 census, making it the List of cities in North Dakota, ninth most populous city in North ...

. Built from April 1952 to September 1953, the dam measures long at the crest and 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 Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of Clay mineral, clay minerals (hydrous aluminium phyllosilicates, e.g., Kaolinite, kaolin, aluminium, Al2Silicon, Si2Oxygen, O5(hydroxide, OH)4) and tiny f ...

where the James River cut a canyon up to wide and deep. The shale (called Pierre Shale) has a dark gray, bedded appearance, and is mostly

claystone Mudrocks are a class of fine-grained siliciclastic sedimentary rocks. The varying types of mudrocks include siltstone, claystone, mudstone and shale. Most of the particles of which the stone is composed are less than and are too small to ...

siltstone Siltstone, also known as aleurolite, is a clastic sedimentary rock that is composed mostly of silt. It is a form of mudrock with a low clay mineral content, which can be distinguished from shale by its lack of fissility. Although its permeabil ...

. The valley also contains many traces of

alluvium Alluvium (, ) is loose clay, silt, sand, or gravel that has been deposited by running water in a stream bed, on a floodplain, in an alluvial fan or beach, or in similar settings. Alluvium is also sometimes called alluvial deposit. Alluvium is ...

, mainly deposited during the last

ice age An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages, and g ...

when the area was heavily

glaciated A glacier (; or ) is a persistent body of dense ice, a form of rock, that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires d ...

Construction

Proposal and companies involved

The dam was proposed in 1951. The site selected offered the required storage with the smallest dam and with close access to embankment materials; however, the underlying rock and soil was both unstable and pervious. The problems were considered minor because the extended storage need of the reservoir only consisted of the lower of the reservoir. If this had not compensated for the pervious material, the required excavations to stabilize the dam would have been over to solid

bedrock In geology, bedrock is solid rock that lies under loose material ( regolith) within the crust of Earth or another terrestrial planet. Definition Bedrock is the solid rock that underlies looser surface material. An exposed portion of bed ...

. Bids for dam construction were submitted by several companies in early 1952. A bid of $1,868,862 was offered by the C.F. Lytle Company of

Sioux City Sioux City () is a city in Woodbury and Plymouth counties in the U.S. state of Iowa. The population was 85,797 in the 2020 census, making it the fourth-most populous city in Iowa. The county seat of Woodbury County, Sioux City is the primar ...

Iowa Iowa ( ) is a U.S. state, state in the upper Midwestern United States, Midwestern region of the United States. It borders the Mississippi River to the east and the Missouri River and Big Sioux River to the west; Wisconsin to the northeast, Ill ...

. This bid was accepted, and the contract was awarded on March 25, 1952 with the notice to proceed received on March 31. The

outlet works A gatehouse, gate house, outlet works or valve house for a dam is a structure housing sluice gates, valves, or pumps (in which case it is more accurately called a pumping station). Many gatehouses are strictly utilitarian, but especially in the ni ...

, which consist of four high-pressure

floodgate Floodgates, also called stop gates, are adjustable gates used to control water flow in flood barriers, reservoir, river, stream, or levee systems. They may be designed to set spillway crest heights in dams, to adjust flow rates in sluices and ...

s, were provided by the Hardie-Tynes Manufacturing Company of

Birmingham Birmingham ( ) is a City status in the United Kingdom, city and metropolitan borough in the metropolitan county of West Midlands (county), West Midlands, within the wider West Midlands (region), West Midlands region, in England. It is the Lis ...

Alabama Alabama ( ) is a U.S. state, state in the Southeastern United States, Southeastern and Deep South, Deep Southern regions of the United States. It borders Tennessee to the north, Georgia (U.S. state), Georgia to the east, Florida and the Gu ...

, at a cost of $72,995. This contract was awarded on March 10, 1952, and the final shipment of the gates was made during February 1953.

Construction process

Construction began in April 1952. Excavation for the outlet works began the construction process, with excavation for the wide foundation trench beginning in mid-May and excavation for the

spillway A spillway is a structure used to provide the controlled release of water downstream from a dam or levee, typically into the riverbed of the dammed river itself. In the United Kingdom, they may be known as overflow channels. Spillways ensure tha ...

following in early June. This wide trench served to remove as much unstable material from the foundation as possible. This material was determined to be unsuitable for construction of the dam, and eventually discarded. Placement of concrete commenced in late June. Embankment construction began in late July. The upper portion of the upstream slope of the dam was covered with a layer of

riprap Riprap (in North American English), also known as rip rap, rip-rap, shot rock, rock armour (in British English) or rubble, is human-placed rock or other material used to protect shoreline structures against scour and water, wave, or ice erosion. ...

, and the lower section was protected by a layer of gravel. By the end of 1952, the construction work was approximately 67% complete. Construction continued at a rapid pace after the beginning of the 1953 season. The upstream conduits for the outlet works were completed in April, and the four high pressure gates were installed beginning April 1. These and the spillway were all complete by August 31, and the main embankment was finished by September 11. On September 18, the final concrete placement occurred, and on September 20, 1953, the dam was completed under the primary contract, 251 days ahead of schedule.

Dam and reservoir

The Jamestown Dam is long at the crest and above the streambed of the

. Measured from the deepest point of excavation to the crest, the height is . Its maximum thickness is from upstream toe to downstream toe. The dam embankment contains of material, primarily dirt, rock, gravel and

. The dam's typical release rate is . The

are controlled by four identical high-pressure gates, 5 feet by 6 feet (1.5 by 1.8 m) in size. Two are for normal use and two are for emergency releases. The maximum capacity of the outlet works is per second, or per second per gate. The dam also has an emergency inverted-bell spillway, capable of handling per second. The total release capacity of the dam is per second. The outlet works are designed to allow for possible future installation of

hydroelectric Hydroelectricity, or hydroelectric power, is Electricity generation, electricity generated from hydropower (water power). Hydropower supplies 15% of the world's electricity, almost 4,210 TWh in 2023, which is more than all other Renewable energ ...

generators and future municipal water supply. The Jamestown Reservoir typically holds of water, with a normal surface area of . Its maximum capacity is and maximum surface area is over .

Flood control

The Jamestown Dam's primary purpose is flood control, and has prevented approximately $36 million in flood-related damages. When it was constructed, certain deficiencies were noted in the foundations for the dam. When the reservoir is at normal levels, the failure risk is small, but as the water level rises, the potential for collapse increases. Floods in May 1969 caused the reservoir to rise to its record level, over , causing leakage of the dam. This level was not even half the reservoir's maximum capacity of . In 1993 and 1995, floods caused the lake to rise to within of the 1969 level. An inspection by the

Bureau of Reclamation The Bureau of Reclamation, formerly the United States Reclamation Service, is a List of United States federal agencies, federal agency under the U.S. Department of the Interior, which oversees water resource management, specifically as it ...

's Dam Safety Department revealed that the dam could potentially fail if the deficiencies were not corrected. As a result, eight

relief well Relief is a sculptural method in which the sculpted pieces remain attached to a solid background of the same material. The term ''relief'' is from the Latin verb , to raise (). To create a sculpture in relief is to give the impression that th ...

s (wells that drain a pervious stratum) were installed in the dam in 1995, and a heavy gravel filter blanket to prevent erosion of embankment materials during seepage was constructed in the spring of 1996.

Recreation

Besides flood control, the long, Jamestown Reservoir was also created for the secondary purpose of recreation, which mainly involves

camping Camping is a form of outdoor recreation or outdoor education involving overnight stays with a basic temporary shelter such as a tent. Camping can also include a recreational vehicle, sheltered cabins, a permanent tent, a shelter such as a Bivy bag ...

boating Boating is the leisurely activity of travelling by boat, or the recreational use of a boat whether powerboats, sailboats, or man-powered vessels (such as rowing and paddle boats), focused on the travel itself, as well as sports activities, suc ...

fishing Fishing is the activity of trying to catch fish. Fish are often caught as wildlife from the natural environment (Freshwater ecosystem, freshwater or Marine ecosystem, marine), but may also be caught from Fish stocking, stocked Body of water, ...

, and

birding Birdwatching, or birding, is the observing of birds, either as a recreational activity or as a form of citizen science. A birdwatcher may observe by using their naked eye, by using a visual enhancement device such as binoculars or a telescope, ...

managed by the Stutsman County Park Board. The lake has approximately of shoreline and is referred to as "one of the greatest migratory waterfowl flyways in North Dakota." It is stocked with fish by the

North Dakota Game and Fish Department The North Dakota Game and Fish Department is the U.S. State, State of North Dakota's State agency charged with stewardship of the state's fish, Game (hunting), game, and wildlife resources. The department sets fish and game regulations, including i ...

. Common fish species in the reservoir include

pike Pike, Pikes or The Pike may refer to: Fish * Blue pike or blue walleye, an extinct color morph of the yellow walleye ''Sander vitreus'' * Ctenoluciidae, the "pike characins", some species of which are commonly known as pikes * ''Esox'', genus of ...

walleye The walleye (''Sander vitreus'', Synonym (taxonomy), synonym ''Stizostedion vitreum''), also called the walleyed pike, yellow pike, yellow pikeperch or yellow pickerel, is a freshwater perciform fish native to most of Canada and to the Northern ...

crappie Crappies () are two species of North American freshwater fish of the genus ''Pomoxis'' in the family Centrarchidae (sunfishes). Both species of crappies are popular game fish among recreational anglers. Etymology The genus name ''Pomoxi ...

bluegill The bluegill (''Lepomis macrochirus''), sometimes referred to as "bream", "brim", "sunny", or, in Texas, "copper nose", is a species of North American freshwater fish, native to and commonly found in streams, rivers, lakes, ponds and wetlands ea ...

smallmouth bass The smallmouth bass (''Micropterus dolomieu'') is a species of freshwater fish in the Centrarchidae, sunfish family (biology), family (Centrarchidae) of the order (biology), order Centrarchiformes. It is the type species of its genus ''Micropterus ...

muskie The muskellunge (''Esox masquinongy''), often shortened to muskie, musky, ski, or lunge, is a species of large freshwater predatory fish native to North America. It is the largest member of the pike family, Esocidae. Origin of name The name ...

and bullhead.

Geology

The Bureau of Reclamation details the geology of the reservoir area:

External links

Jamestown Dam Project (official website)
U.S. Bureau of Reclamation
Jamestown Reservoir - Discover Jamestown, ND

References

{{Omaha District dams Dams in North Dakota Buildings and structures in Stutsman County, North Dakota Earth-filled dams Jamestown, North Dakota United States Bureau of Reclamation dams Dams completed in 1953