Willow Creek
Willow Creek is an earth dam located in Brown County, South Dakota, built in 1934. It carries a High hazard potential classification and has a fair condition assessment.
About Willow Creek
The primary purpose of Willow Creek is water supply. The dam stores water for municipal, industrial, or agricultural use, helping ensure a reliable supply for the surrounding area. The dam is owned by City Of Aberdeen (local government). It impounds the Willow Creek near Westport.
The dam stands 49 feet tall and stretches 1,330 feet across, creates a reservoir covering 312 acres, has a maximum storage capacity of 7,650 acre-feet, and collects water from a drainage area of 155 square miles. Completed in 1934, 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. Its condition is rated fair — the dam has minor deficiencies that are being addressed or do not pose an immediate safety threat. An emergency action plan is in place for this dam. The most recent inspection on record was 11/22/2022.
At 49 feet, this dam is taller than 92% of dams nationwide.
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 | Brown |
| Nearest City | Westport |
| River/Stream | Willow Creek |
| Coordinates | 45.71436, -98.59060 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 49 ft |
| Dam Height | 49 ft |
| Dam Length | 1,330 ft |
| Year Completed | 1934 (92 years old) |
Storage & Hydraulics
| NID Storage | 7,650 acre-ft |
| Max Storage | 7,650 acre-ft |
| Normal Storage | 3,050 acre-ft |
| Surface Area | 312 acres |
| Drainage Area | 155 sq mi |
| Max Discharge | 17,900 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Water Supply |
| Owner | CITY OF ABERDEEN |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Fair |
| Last Inspection | 11/22/2022 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | SD00008 |
| Federal ID | SD00008 |
| More Info | State Dam Safety Program |