Farley Lake Dam
Farley Lake Dam is an earth dam located in Grant County, South Dakota, built in 1910. It carries a High hazard potential classification and has a fair condition assessment.
About Farley Lake Dam
The primary purpose of Farley Lake Dam 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 Milbank (local government). It impounds the Whetstone River near Milbank.
The dam stands 15 feet tall and stretches 2,800 feet across, creates a reservoir covering 20 acres, has a maximum storage capacity of 1,300 acre-feet, and collects water from a drainage area of 74 square miles. Completed in 1910, the structure is over a century 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. Its condition is rated fair — the dam has minor deficiencies that are being addressed or do not pose an immediate safety threat. The most recent inspection on record was 08/04/2022.
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 | Grant |
| Nearest City | Milbank |
| River/Stream | Whetstone River |
| Coordinates | 45.22825, -96.64375 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 15 ft |
| Dam Height | 15 ft |
| Dam Length | 2,800 ft |
| Year Completed | 1910 (116 years old) |
Storage & Hydraulics
| NID Storage | 1,300 acre-ft |
| Max Storage | 1,300 acre-ft |
| Normal Storage | 340 acre-ft |
| Surface Area | 20 acres |
| Drainage Area | 74 sq mi |
| Max Discharge | 5,400 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Water Supply |
| Owner | CITY OF MILBANK |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Fair |
| Last Inspection | 08/04/2022 |
Identifiers
| NID ID | SD01030 |
| Federal ID | SD01030 |
| More Info | State Dam Safety Program |