Overview
Angostura dam is a composite type, consisting of a concrete gravity structure and an earth embankment. The concrete portion of the dam comprises a gated spillway section located in the river channel and two non-overflow sections, one extending to the left abutment and one abutting the earth embankment extending to the right abutment. The dam has a crest length of 2,030 feet; the concrete section is 970 feet long and the earth embankment 1,060 feet long, with a structural height of 193 feet and a hydraulic height of 136 feet above the riverbed.
The spillway is an overflow section in the concrete portion of the dam, controlled by five 50- by 30-foot radial gates. Discharge capacity is 247,000 cubic feet per second. The river outlet works consists of a 4.5-foot diameter steel conduit through the concrete dam section, controlled by one 4-foot-square high-pressure slide gate in the valve house at the downstream end. Discharge capacity is 590 cubic feet per second. The main canal outlet works for irrigation water delivery consists of a 6-foot-diameter steel conduit through the concrete dam terminating in a valve house, a stilling basin, and canal headworks at the downstream end. Releases into the 290-cubic- foot-per-second-capacity canal are controlled by two 3.5-foot-square high-pressure slide gates in the valve house.
General
| Project | PSMBP - Angostura |
| Longitude | -103.4378 |
| Latitude | 43.3431 |
| Watercourse | Cheyenne River |
| Reservoir | Angostura |
| Original Construction | 1946-1949 |
| National ID Number | SD01099 |
| Base Width | 230 ft |
Dimensions
| Crest Elevation | 3199.0 ft |
| Structural Height | 193 ft |
| Hydraulic Height (Normal Operating Depth at Dam) | 136 ft |
| Crest Width | 10 ft |
| Volume of Dam Construction Materials | 850000 cu yd |
| Crest Length | 2030 ft |
Hydraulics & Hydrology
| Spillway Capacity at Elevation | 247000 cfs at 3198.1 |
| Outlet Works Capacity at Elevation | 590 cfs at 3198.1 |
| Hydrometeorological Report (HMR) | HMR 51-52 |
| Maximum Water Surface Elevation | 3198.1 ft |
| Total Water Storage at Elevation | 138761 acre-ft at 3187.2 |
| Drainage Area | 9034 sq mi |
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