Eleven Mile Canyon
Eleven Mile Canyon is a concrete dam located in Park County, Colorado, built in 1932. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Eleven Mile Canyon
The primary purpose of Eleven Mile Canyon 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 Denver Board Of Water Commissioners (public utility). It impounds the South Platte River near Lake George.
The dam stands 151 feet tall and stretches 375 feet across, creates a reservoir covering 3,500 acres, has a maximum storage capacity of 128,000 acre-feet, and collects water from a drainage area of 963 square miles. Completed in 1932, 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 satisfactory, indicating no existing or potential dam safety deficiencies are recognized. An emergency action plan is in place for this dam. The most recent inspection on record was 08/24/2022.
At 151 feet, this dam is taller than 99% 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 Colorado 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 | Colorado |
| County | Park |
| Nearest City | Lake George |
| River/Stream | South Platte River |
| Coordinates | 38.90501, -105.47723 |
Physical Characteristics
| Dam Type | Concrete |
| NID Height | 151 ft |
| Dam Height | 128 ft |
| Dam Length | 375 ft |
| Year Completed | 1932 (94 years old) |
Storage & Hydraulics
| NID Storage | 128,000 acre-ft |
| Max Storage | 128,000 acre-ft |
| Normal Storage | 97,800 acre-ft |
| Surface Area | 3,500 acres |
| Drainage Area | 963 sq mi |
| Max Discharge | 3,500 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Water Supply |
| Owner | DENVER BOARD OF WATER COMMISSIONERS |
| Owner Type | Public Utility |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 08/24/2022 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CO00359 |
| Federal ID | CO00359 |
| More Info | State Dam Safety Program |