Angostura Dam
Angostura Dam is a concrete dam located in Fall River County, South Dakota, built in 1949. It carries a High hazard potential classification.
About Angostura Dam
The primary purpose of Angostura Dam is irrigation. The dam stores and diverts water for agricultural irrigation, supporting farming operations in the surrounding area. The dam is owned by Bureau Of Reclamation (federal). It impounds the Cheyenne River near Wasta.
The dam stands 193 feet tall and stretches 2,030 feet across, creates a reservoir covering 4,706 acres, has a maximum storage capacity of 197,100 acre-feet, and collects water from a drainage area of 9,096 square miles. Completed in 1949, the structure is well-established, with more than 75 years of service.
This dam carries a high hazard potential classification, which means that a failure or uncontrolled release of water would likely cause loss of human life. This classification reflects the consequences of failure, not the likelihood — it indicates that people live or work in the area downstream. An emergency action plan is in place for this dam. The most recent inspection on record was 08/26/2020.
At 193 feet, this dam is taller than 99% of all dams in the United States.
Living Downstream
If you live or work downstream of this dam, consider taking these steps: learn your local evacuation routes, check whether your county emergency management office has a dam failure inundation map, and sign up for local emergency alerts. The South Dakota dam safety program can provide more specific information about emergency planning for this structure.
Search for dams near your address to see all dams in your area with hazard classifications and safety data.
Location
| State | South Dakota |
| County | Fall River |
| Nearest City | Wasta |
| River/Stream | Cheyenne River |
| Coordinates | 43.34340, -103.43820 |
Physical Characteristics
| Dam Type | Concrete |
| NID Height | 193 ft |
| Dam Height | 193 ft |
| Dam Length | 2,030 ft |
| Year Completed | 1949 (77 years old) |
Storage & Hydraulics
| NID Storage | 197,100 acre-ft |
| Max Storage | 197,100 acre-ft |
| Normal Storage | 86,160 acre-ft |
| Surface Area | 4,706 acres |
| Drainage Area | 9,096 sq mi |
| Max Discharge | 247,000 cfs |
| Spillway Type | Controlled |
Ownership & Safety
| Purpose | Irrigation |
| Owner | BUREAU OF RECLAMATION |
| Owner Type | Federal |
| Hazard Classification | High |
| Condition Assessment | Not Available |
| Last Inspection | 08/26/2020 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | SD01099 |
| Federal ID | SD01099 |
| More Info | State Dam Safety Program |