Pactola Dike 1
Pactola Dike 1 is an earth dam located in Pennington County, South Dakota, built in 1956. It carries a High hazard potential classification.
About Pactola Dike 1
Pactola Dike 1 is a dam in Pennington, South Dakota. The dam is owned by Bureau Of Reclamation (federal). It impounds the Rapid Creek near Rapid City, Sd.
The dam stands 115 feet tall and stretches 1,806 feet across, creates a reservoir covering 1,557 acres, has a maximum storage capacity of 140,898 acre-feet, and collects water from a drainage area of 229 square miles. Completed in 1956, the structure is well into its service life at over 50 years old.
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 05/04/2023.
At 115 feet, this dam is taller than 98% 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 | Pennington |
| Nearest City | Rapid City, Sd |
| River/Stream | Rapid Creek |
| Coordinates | 44.07720, -103.48960 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 115 ft |
| Dam Height | 115 ft |
| Dam Length | 1,806 ft |
| Year Completed | 1956 (70 years old) |
Storage & Hydraulics
| NID Storage | 140,898 acre-ft |
| Max Storage | 140,898 acre-ft |
| Normal Storage | 55,985 acre-ft |
| Surface Area | 1,557 acres |
| Drainage Area | 229 sq mi |
| Spillway Type | Controlled |
Ownership & Safety
| Owner | BUREAU OF RECLAMATION |
| Owner Type | Federal |
| Hazard Classification | High |
| Condition Assessment | Not Available |
| Last Inspection | 05/04/2023 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | SD01139 |
| Federal ID | SD01139S001 |
| More Info | State Dam Safety Program |