# Garrison

SPP asset profile · https://askthegrid.com/assets/facilities/garrison

U.S. Army Corps of Engineers, Omaha District - Mercer County - SPP

Garrison Dam is a federally owned conventional hydroelectric plant on the Missouri River near Riverdale in Mercer County, North Dakota, impounding Lake Sakakawea. The powerhouse holds five generating units brought online between 1956 and 1960, totaling 583.4 MW of nameplate capacity (510 MW net summer), and is built and run by the U.S. Army Corps of Engineers' Omaha District. All five units remain in service, with no whole-plant or unit retirements scheduled. Hydropower here is a byproduct of the dam's primary flood-control, navigation, irrigation and water-supply mission on the upper Missouri River mainstem system.

## Metrics

- **Nameplate capacity:** 583.4 MW — Canonical EIA plant baseline.
- **Registry anchor:** Plant 2815 — plant-2815

## Facts

- **Technology:** Conventional Hydroelectric
- **Operator:** U.S. Army Corps of Engineers, Omaha District

## Related parties

- **Owner / operator / developer:** U.S. Army Corps of Engineers, Omaha District — Garrison was constructed and is owned by the Corps of Engineers, Department of the Army. ([source](https://www.nwo.usace.army.mil/Missions/Dam-and-Lake-Projects/Missouri-River-Dams/Garrison))
- **Construction contractor:** Yellowstone Electric Co. — Powerhouse rehabilitation contractor
- **Construction contractor:** Koontz Electric Company, Inc. — Switchyard design-build contractor ([source](https://koontzelectric.com/project/garrison-dam-switchyard-upgrade))
- **Offtaker / power marketer:** Minnkota Power Cooperative — Power purchaser ([source](https://www.minnkota.com/minnkota-website/our-power/hydro))

## Sources

- [koontzelectric.com](https://koontzelectric.com/project/garrison-dam-switchyard-upgrade) — koontzelectric.com · public_source — Source retained for exact-record publication review.
- [mbrweb.ferc.gov](https://mbrweb.ferc.gov/SearchlkpEIA/Index?page=551) — mbrweb.ferc.gov · authoritative — Source retained for exact-record publication review.
- [usace.contentdm.oclc.org](https://usace.contentdm.oclc.org/digital/api/collection/p16021coll7/id/23132/download) — usace.contentdm.oclc.org · public_source — Source retained for exact-record publication review.
- [water.usace.army.mil](https://water.usace.army.mil/cda/documents/wc/2901/GarrisonDamWCM_Final_Dec2018_Redacted.pdf) — water.usace.army.mil · public_source — Source retained for exact-record publication review.
- [army.mil](https://www.army.mil/article/26767/arra_corps_of_engineers_accelerates_garrison_dam_powerhouse_rehabilitation) — army.mil · public_source — Source retained for exact-record publication review.
- [minnkota.com](https://www.minnkota.com/minnkota-website/our-power/hydro) — minnkota.com · public_source — Source retained for exact-record publication review.

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Canonical page: https://askthegrid.com/assets/facilities/garrison
Website: [U.S. Army Corps of Engineers](https://www.nwo.usace.army.mil/Missions/Dam-and-Lake-Projects/Missouri-River-Dams/Garrison)

Source: Ask the Grid — https://askthegrid.com/