Major Lake is an earth dam located in Pennington County, South Dakota, built in 1939. It carries a High hazard potential classification.
Dam profile
NID height · 18 ft18 ft tall and 310 ft long. Height is drawn to scale against a two-story house, about 25 ft; the profile is a generic embankment section and the water level is illustrative.
About Major Lake
The primary purpose of Major Lake is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Usda Fs (federal). It impounds the Spring Cr Trib near Hill City.
The dam stands 18 feet tall and stretches 310 feet across, has a maximum storage capacity of 73 acre-feet, and collects water from a drainage area of 32 square miles. Completed in 1939, 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 09/05/2019. That was 7 years ago, which is on the longer end for a high-hazard structure.
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 | Hill City |
| River/Stream | Spring Cr Trib |
| Coordinates | 43.93590, -103.56819 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 18 ft |
| Dam Height | 13 ft |
| Dam Length | 310 ft |
| Year Completed | 1939 (87 years old) |
Storage & Hydraulics
| NID Storage | 73 acre-ft |
| Max Storage | 73 acre-ft |
| Normal Storage | 29 acre-ft |
| Drainage Area | 32 sq mi |
| Max Discharge | 1,030 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | Usda Fs |
| Owner Type | Federal |
| Hazard Classification | High |
| Condition Assessment | Not assessed |
| Last Inspection | 09/05/2019 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | SD02225 |
| Federal ID | SD02225 |
| More Info | State Dam Safety Program |