Helena Valley Dike
Helena Valley Dike is an earth dam located in Lewis and Clark County, Montana, built in 1959. It carries a High hazard potential classification.
About Helena Valley Dike
The primary purpose of Helena Valley Dike 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).
The dam stands 30 feet tall and stretches 890 feet across, creates a reservoir covering 531 acres, has a maximum storage capacity of 10,702 acre-feet, and collects water from a drainage area of 3 square miles. Completed in 1959, 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 07/28/2020.
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 Montana 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 | Montana |
| County | Lewis and Clark |
| Nearest City | Helena |
| Coordinates | 46.63790, -111.88290 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 30 ft |
| Dam Height | 30 ft |
| Dam Length | 890 ft |
| Year Completed | 1959 (67 years old) |
Storage & Hydraulics
| NID Storage | 10,702 acre-ft |
| Max Storage | 10,702 acre-ft |
| Normal Storage | 10,451 acre-ft |
| Surface Area | 531 acres |
| Drainage Area | 3 sq mi |
| Spillway Type | None |
Ownership & Safety
| Purpose | Irrigation |
| Owner | BUREAU OF RECLAMATION |
| Owner Type | Federal |
| Hazard Classification | High |
| Condition Assessment | Not Available |
| Last Inspection | 07/28/2020 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | MT00743 |
| Federal ID | MT00743S001 |
| More Info | State Dam Safety Program |