Blunn
Blunn is an earth dam located in Jefferson County, Colorado, built in 1979. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Blunn
The primary purpose of Blunn 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 Arvada (essert, Wendy) (local government). It impounds the Ralston Creek near Arvada.
The dam stands 125 feet tall and stretches 4,180 feet across, creates a reservoir covering 198 acres, has a maximum storage capacity of 7,839 acre-feet, and collects water from a drainage area of 49 square miles. Completed in 1979, the structure is 47 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. 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 03/16/2022.
At 125 feet, this dam is taller than 98% 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 | Jefferson |
| Nearest City | Arvada |
| River/Stream | Ralston Creek |
| Coordinates | 39.82299, -105.20432 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 125 ft |
| Dam Height | 68 ft |
| Dam Length | 4,180 ft |
| Year Completed | 1979 (47 years old) |
Storage & Hydraulics
| NID Storage | 7,839 acre-ft |
| Max Storage | 7,839 acre-ft |
| Normal Storage | 6,361 acre-ft |
| Surface Area | 198 acres |
| Drainage Area | 49 sq mi |
| Max Discharge | 64,000 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Water Supply |
| Owner | CITY OF ARVADA (ESSERT, WENDY) |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 03/16/2022 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CO00980 |
| Federal ID | CO00980 |
| More Info | State Dam Safety Program |