Gavins Point Dam is a long

embankment Embankment may refer to: Geology and geography * A levee, an artificial bank raised above the immediately surrounding land to redirect or prevent flooding by a river, lake or sea * Embankment (earthworks), a raised bank to carry a road, railwa ...

rolled-earth and chalk-fill

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 ...

which spans the Missouri River and impounds

Lewis and Clark Lake Lewis and Clark Lake is a 31,400 acre (130 km²) reservoir located on the border of the U.S. states of Nebraska and South Dakota on the Missouri River. The lake is approximately in length with over of shoreline and a maximum water depth ...

. The dam joins

Cedar County, Nebraska Cedar County is a county in the U.S. state of Nebraska. As of the 2010 United States Census, the population was 8,852. The county seat is Hartington. The county was formed in 1857, and was named for the Cedar tree groves in the area. In the ...

with

Yankton County, South Dakota Yankton County is a County (United States), county in the U.S. state of South Dakota. As of the 2020 United States Census, the population was 23,310. Its county seat is Yankton, South Dakota, Yankton. Yankton County comprises the Yankton, SD Mi ...

a distance of 811.1 river miles (1,305 km) upstream of

St. Louis, Missouri St. Louis () is the second-largest city in Missouri, United States. It sits near the confluence of the Mississippi River, Mississippi and the Missouri Rivers. In 2020, the city proper had a population of 301,578, while the Greater St. Louis, ...

, where the river joins the

Mississippi River The Mississippi River is the second-longest river and chief river of the second-largest drainage system in North America, second only to the Hudson Bay drainage system. From its traditional source of Lake Itasca in northern Minnesota, it f ...

. The dam and

hydroelectric power plant Hydroelectricity, or hydroelectric power, is electricity generated from hydropower (water power). Hydropower supplies one sixth of the world's electricity, almost 4500 TWh in 2020, which is more than all other renewable sources combined an ...

were constructed as the Gavins Point Project from 1952 to 1957 by the

United States Army Corps of Engineers , colors = , anniversaries = 16 June (Organization Day) , battles = , battles_label = Wars , website = , commander1 = ...

as part of the Pick-Sloan Plan. The dam is located approximately 4 miles (6.4 km) west or upstream of

Yankton, South Dakota Yankton is a city in and the county seat of Yankton County, South Dakota, United States. The population was 15,411 at the 2020 census, and it is the principal city of the Yankton Micropolitan Statistical Area, which includes the entirety of Y ...

History and background

Gavins Point Dam was constructed as a part of the Pick–Sloan Missouri Basin Program, authorized by the

Flood Control Act of 1944 The Pick-Sloan Flood Control Act of 1944 (P.L. 78–534), enacted in the 2nd session of the 78th Congress, is U.S. legislation that authorized the construction of numerous dams and modifications to previously existing dams, as well as levees acros ...

Congress A congress is a formal meeting of the representatives of different countries, constituent states, organizations, trade unions, political parties, or other groups. The term originated in Late Middle English to denote an encounter (meeting of a ...

. The dam is named after Gavins Point, a

bluff Bluff or The Bluff may refer to: Places Australia * Bluff, Queensland, Australia, a town * The Bluff, Queensland (Ipswich), a rural locality in the city of Ipswich * The Bluff, Queensland (Toowoomba Region), a rural locality * Bluff River (New ...

along the northern bank of the Missouri River named for an early settler, now within the western end of Lewis & Clark Recreation Area, which was to be the original location of construction of the dam. The location was moved and construction began further downstream along

Calumet Bluff Calumet Bluff is a hill about 180 feet high overlooking Lewis and Clark Lake and the Missouri River in Cedar County, Nebraska, U.S., where the Lewis and Clark Expedition held its first council with the Sioux Indians for two days in 1804. Today t ...

because this location offered a shorter span distance and less fill material needed for dam construction, although the project kept the original name. The dam operations work in conjunction with the other Pick-Sloan Program Dams to assist with conservation, control, and use of

water resources Water resources are natural resources of water that are potentially useful for humans, for example as a source of drinking water supply or irrigation water. 97% of the water on the Earth is salt water and only three percent is fresh water; slight ...

in the

Missouri River Basin The Missouri River Valley outlines the journey of the Missouri River from its headwaters where the Madison, Jefferson and Gallatin Rivers flow together in Montana to its confluence with the Mississippi River in the State of Missouri. At long th ...

. The intended beneficial uses of these water resources include

flood control Flood control methods are used to reduce or prevent the detrimental effects of flood waters."Flood Control", MSN Encarta, 2008 (see below: Further reading). Flood relief methods are used to reduce the effects of flood waters or high water level ...

, aids to

navigation Navigation is a field of study that focuses on the process of monitoring and controlling the movement of a craft or vehicle from one place to another.Bowditch, 2003:799. The field of navigation includes four general categories: land navigation, ...

irrigation Irrigation (also referred to as watering) is the practice of applying controlled amounts of water to land to help grow Crop, crops, Landscape plant, landscape plants, and Lawn, lawns. Irrigation has been a key aspect of agriculture for over 5,00 ...

, supplemental

water supply Water supply is the provision of water by public utilities, commercial organisations, community endeavors or by individuals, usually via a system of pumps and pipes. Public water supply systems are crucial to properly functioning societies. Thes ...

power generation Electricity generation is the process of generating electric power from sources of primary energy. For utilities in the electric power industry, it is the stage prior to its delivery ( transmission, distribution, etc.) to end users or its stor ...

, municipal and industrial water supplies, stream-pollution abatement,

sediment control A sediment control is a practice or device designed to keep eroded soil on a construction site, so that it does not wash off and cause water pollution to a nearby stream, river, lake, or sea. Sediment controls are usually employed together with er ...

preservation Preservation may refer to: Heritage and conservation * Preservation (library and archival science), activities aimed at prolonging the life of a record while making as few changes as possible * ''Preservation'' (magazine), published by the Nat ...

and enhancement of

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...

and

wildlife Wildlife refers to domestication, undomesticated animal species (biology), species, but has come to include all organisms that grow or live wilderness, wild in an area without being species, introduced by humans. Wildlife was also synonymous ...

, and creation of recreation opportunities. Gavins Point is the most downstream dam on the Missouri River, being 811.1 river miles upstream of

St. Louis St. Louis () is the second-largest city in Missouri, United States. It sits near the confluence of the Mississippi and the Missouri Rivers. In 2020, the city proper had a population of 301,578, while the bi-state metropolitan area, which e ...

where the river meets the

. The next dam upstream is

Fort Randall Dam Fort Randall Dam is a earthen dam which spans the Missouri River and impounds Lake Francis Case, the 11th-largest reservoir in the U.S. The dam joins Gregory and Charles Mix counties, South Dakota a distance of 880 river miles (1,416 km) u ...

2011 Missouri River Flood

During the 2011 Missouri River Flood, the dam released a record water flow of 160,200 cfs, topping the previous record of 70,000 cfs in 1997. During the 2011 flood, the debris damaged the dam and a significant portion of rocks were dislodged from its upstream side. The U.S. Army Corps of Engineers soon began repairs to the dam and its

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 ...

gates. Pressure sensors were also installed in concrete portion of the dam.

Hydroelectric power generation

The dam has a

hydroelectric power Hydroelectricity, or hydroelectric power, is electricity generated from hydropower (water power). Hydropower supplies one sixth of the world's electricity, almost 4500 TWh in 2020, which is more than all other renewable sources combined and ...

plant with three generators, each having a

nameplate capacity Nameplate capacity, also known as the rated capacity, nominal capacity, installed capacity, or maximum effect, is the intended full-load sustained output of a facility such as a power station,

of 44,099 kW, for a total of 132.297 MW. The hydroelectric power plant provides enough electricity to supply 68,000 homes. Power generated is sold through the

Western Area Power Administration As one of the four power marketing administrations within the U.S. Department of Energy, the Western Area Power Administration (WAPA)'s role is to market wholesale hydropower generated at 57 hydroelectric federal dams operated by the Bureau of R ...

Reservoir

''See main article:

Gavins Point Dam creates Lewis and Clark Lake, a popular regional tourist destination for water-based recreational opportunities including boating and fishing, along with camping, hiking, and hunting opportunities managed by the State of South Dakota, State of Nebraska, and the U.S. Army Corps of Engineers. The lake is significantly impacted by

sedimentation Sedimentation is the deposition of sediments. It takes place when particles in suspension settle out of the fluid in which they are entrained and come to rest against a barrier. This is due to their motion through the fluid in response to the ...

and

siltation Siltation, is water pollution caused by particulate terrestrial clastic material, with a particle size dominated by silt or clay. It refers both to the increased concentration of suspended sediments and to the increased accumulation (temporary or ...

issues, diminishing the overall water surface area, water storage capacity, and recreational opportunities.

Sediment Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand an ...

carried by the Missouri River and

Niobrara River The Niobrara River (; oma, Ní Ubthátha khe, , literally "water spread-out horizontal-the" or "The Wide-Spreading Water") is a tributary of the Missouri River, approximately long,U.S. Geological Survey. Many early settlers, such as Mari Sando ...

is slowed and trapped within the reservoir due to the dam impounding and thus stopping the natural river flow. Studies show approximately 5.1 million tons of sediment are deposited in the lake each year, which contributes to the lake's increasing size of delta area on the western portions of the lake. Approximately 60% of the sediment comes from the Nebraska Sandhills via the Niobrara River. As of 2016, approximately 30% of the lake's overall surface area has diminished due to sedimentation deposits, and some figures project by 2045 approximately 50% of the lake will be diminished due to sedimentation deposits. Presently, there is no plan or solution to remove or slow the progression of the siltation within the lake.http://msaconline.com/

References

External links

U.S. Army Corps of Engineers, Omaha District - Gavins Point Project
(Official Site)
Missouri River Water Management Division - U.S. Army Corps of EngineersMissouri River Basin Daily Bulletin - USACE
{{Authority control Buildings and structures in Cedar County, Nebraska Dams in Nebraska Dams in South Dakota Hydroelectric power plants in Nebraska Hydroelectric power plants in South Dakota Dams on the Missouri River Buildings and structures in Yankton County, South Dakota United States Army Corps of Engineers dams Dams completed in 1957 Energy infrastructure completed in 1957 Earth-filled dams United States Army Corps of Engineers Energy infrastructure in Nebraska