Gavins Point Dam is a embankment 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, aqua ...

which spans the

Missouri River The Missouri River is a river in the Central United States, Central and Mountain states, Mountain West regions of the United States. The nation's longest, it rises in the eastern Centennial Mountains of the Bitterroot Range of the Rocky Moun ...

and impounds Lewis and Clark Lake. The dam joins

Cedar County, Nebraska Cedar County is a county in the U.S. state of Nebraska. As of the 2020 United States census, the population was 8,380. 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 in the U.S. state of South Dakota. As of the 2020 census, the population was 23,310, making it the 9th most populous county in South Dakota. Its county seat is 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 ( , sometimes referred to as St. Louis City, Saint Louis or STL) is an Independent city (United States), independent city in the U.S. state of Missouri. It lies near the confluence of the Mississippi River, Mississippi and the Miss ...

, where the river joins the

Mississippi River The Mississippi River is the main stem, primary river of the largest drainage basin in the United States. It is the second-longest river in the United States, behind only the Missouri River, Missouri. From its traditional source of Lake Ita ...

. It is the most downstream dam on the Missouri River. The dam and

hydroelectric power plant 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 ...

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

United States Army Corps of Engineers The United States Army Corps of Engineers (USACE) is the military engineering branch of the United States Army. A direct reporting unit (DRU), it has three primary mission areas: Engineer Regiment, military construction, and civil wo ...

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. It became a city in 1889. The population was 15,411 at the 2020 United States census, 2020 census, making it the List of cities in South Dakota, 7th most po ...

History

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 ac ...

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 ...

. The dam is named after Gavins Point, a bluff 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 because this location offered a shorter span distance and less fill material needed for dam construction, although the project kept the original name. Gavins-record

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.

Usage

The dam has a

hydroelectric power 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 ...

plant with three generators, each having a

nameplate capacity Nameplate capacity, also known as the rated capacity, nominal capacity, installed capacity, maximum effect or gross capacity,kW, for a total of 132.297 MW. The hydroelectric power plant provides enough electricity to supply 68,000 homes. The 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 Re ...

. 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. These resources can be either Fresh water, freshwater from natural sources, or water produ ...

in the Missouri River Basin. The intended beneficial uses of these water resources include

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 ...

, aids to

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

irrigation Irrigation (also referred to as watering of plants) is the practice of applying controlled amounts of water to land to help grow crops, landscape plants, and lawns. Irrigation has been a key aspect of agriculture for over 5,000 years and has bee ...

, 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. Th ...

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 stora ...

, 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 e ...

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 A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...

and

wildlife Wildlife refers to domestication, undomesticated animals and uncultivated plant species which can exist in their natural habitat, but has come to include all organisms that grow or live wilderness, wild in an area without being species, introdu ...

, 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 ( , sometimes referred to as St. Louis City, Saint Louis or STL) is an independent city in the U.S. state of Missouri. It lies near the confluence of the Mississippi and the Missouri rivers. In 2020, the city proper had a populatio ...

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) ...

Reservoir

''See main article: Lewis and Clark Lake'' GavinsPointDamAerial

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 th ...

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 o ...

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

Sediment Sediment is a solid material that is transported to a new location where it is deposited. It occurs naturally and, through the processes of weathering and erosion, is broken down and subsequently sediment transport, transported by the action of ...

carried by the Missouri River and

Niobrara River The Niobrara River (; , , 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 Sandoz, referred to the rive ...

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.

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

History

Usage

Reservoir

See also

References

External links