# Angostura Unit Publisher: CapexCue Canonical dossier: Dossier reference: release 1 (0cf79009-91c0-4692-94cc-da040d57633a) Released project intelligence Oldest supporting observation: 2026-10-03T18:18:26.365029+00:00 Dossier released: 2026-10-16T16:26:51.001044+00:00 Source report dates and capture dates are listed per fact below; neither establishes an event date. Original released project name: Angostura Unit. The page heading labels the entry “Angostura Division,” while the narrative identifies the described project as the Angostura Unit. ## Project summary Angostura Unit, listed under the heading “Angostura Division,” is a Reclamation project on the Cheyenne River in southwestern South Dakota. Its described works include Angostura Dam and Reservoir and associated irrigation facilities. The source reports dam completion on December 7, 1949, first irrigation-water delivery in 1953, and irrigation supply for 12,218 acres. ## Evidence limits and unknowns - The supplied project entry gives no publication date and does not establish present physical condition, current operating status, or whether work is underway. - Procurement, investment, financing stage, construction contractor, planned upgrade, and next milestone are not identified in the supplied project entry. Current purchasing availability: unknown. Source-dated plans do not establish current progress or available supplier packages. ## Project metadata Country: United States Region: North America Physical assets: Not classified Derived from the exact released evidence; unresolved fields remain unclassified. ## Project category Water and environment Derived from the reviewed scope statement; delivery stage remains unclassified. The described project comprises Angostura Dam and Reservoir and associated irrigation facilities. The dam is a composite concrete-gravity and earth-embankment structure with a 2,030-foot crest (970 feet concrete and 1,060 feet earth), a structural height of 193 feet, and a hydraulic height of 136 feet above the riverbed. Its spillway has five 50-by-30-foot radial gates and a stated discharge capacity of 247,000 cubic feet per second. The river outlet is a 4.5-foot-diameter steel conduit with a 4-foot-square slide gate and stated capacity of 590 cubic feet per second. The irrigation outlet has a 6-foot-diameter steel conduit, valve house, stilling basin and canal headworks; releases to the canal are controlled by two 3.5-foot-square slide gates. The Angostura Canal has a 29.7-mile alignment and 290-cubic-foot-per-second design capacity, and crosses the Cheyenne River through a 9,800-foot inverted siphon. The described unit lands extend about 24 miles downstream from the dam and are served by 39 miles of laterals and 34 miles of open and closed drains. Dam construction began August 23, 1946, and was completed December 7, 1949. Source: US Bureau of Reclamation screened government project narrative — https://www.usbr.gov/projects/index.php?id=491 | published unknown | observed 2026-10-03T18:18:26.365029+00:00 Project overview Oldest decisive evidence: 2026-10-03T18:18:26.365029+00:00 Newest evidence: 2026-10-03T18:18:26.365029+00:00 Knowledge reviewed: 2026-10-16T16:26:50.659588+00:00 Publication reviewed: 2026-10-16T16:26:50.659588+00:00 ## Name Angostura Unit. The page heading labels the entry “Angostura Division,” while the narrative identifies the described project as the Angostura Unit. Status: reported Attribution: US Bureau of Reclamation government project account Source: US Bureau of Reclamation screened government project narrative — https://www.usbr.gov/projects/index.php?id=491 | published unknown | observed 2026-10-03T18:18:26.365029+00:00 ## Scope The described project comprises Angostura Dam and Reservoir and associated irrigation facilities. The dam is a composite concrete-gravity and earth-embankment structure with a 2,030-foot crest (970 feet concrete and 1,060 feet earth), a structural height of 193 feet, and a hydraulic height of 136 feet above the riverbed. Its spillway has five 50-by-30-foot radial gates and a stated discharge capacity of 247,000 cubic feet per second. The river outlet is a 4.5-foot-diameter steel conduit with a 4-foot-square slide gate and stated capacity of 590 cubic feet per second. The irrigation outlet has a 6-foot-diameter steel conduit, valve house, stilling basin and canal headworks; releases to the canal are controlled by two 3.5-foot-square slide gates. The Angostura Canal has a 29.7-mile alignment and 290-cubic-foot-per-second design capacity, and crosses the Cheyenne River through a 9,800-foot inverted siphon. The described unit lands extend about 24 miles downstream from the dam and are served by 39 miles of laterals and 34 miles of open and closed drains. Dam construction began August 23, 1946, and was completed December 7, 1949. Status: reported Attribution: US Bureau of Reclamation government project account Source: US Bureau of Reclamation screened government project narrative — https://www.usbr.gov/projects/index.php?id=491 | published unknown | observed 2026-10-03T18:18:26.365029+00:00 ## Delivery The source reports a full irrigation-water supply for 12,218 acres of irrigable land. The first irrigation-water delivery was made in 1953. Listed principal crops are alfalfa and corn, with wheat, barley, oats, pasture and forage also grown. Status: reported Attribution: US Bureau of Reclamation government project account Source: US Bureau of Reclamation screened government project narrative — https://www.usbr.gov/projects/index.php?id=491 | published unknown | observed 2026-10-03T18:18:26.365029+00:00 ## Location On the Cheyenne River in southwestern South Dakota, at the southeast edge of the Black Hills, about 9 miles southeast of Hot Springs; the unit lies within Custer and Fall River Counties. Status: reported Attribution: US Bureau of Reclamation government project account Source: US Bureau of Reclamation screened government project narrative — https://www.usbr.gov/projects/index.php?id=491 | published unknown | observed 2026-10-03T18:18:26.365029+00:00 ## Cite this dossier CapexCue — Angostura Unit — dossier released 2026-10-16T16:26:51.001044+00:00, release 1 (0cf79009-91c0-4692-94cc-da040d57633a) — https://capexcue.com/projects/angostura-unit-the-page-heading-labels-the-entry-angostura-division-while-the-narrative-identifies-the-described-project-as-t-377d5ffe62b73e9d/. For current information and later dossier updates, visit . This file records the release identified above; the current dossier may change.