Lower Chinns
Lower Chinns is an earth dam located in Clear Creek County, Colorado, built in 1934. It carries a High hazard potential classification.
About Lower Chinns
The primary purpose of Lower Chinns is irrigation. The dam stores and diverts water for agricultural irrigation, supporting farming operations in the surrounding area. The dam is owned by Agricultural Ditch & Reservoir Company (acker, Pet (private). It impounds the Fall River-tr near Idaho Springs.
The dam stands 18 feet tall and stretches 440 feet across, creates a reservoir covering 12 acres, has a maximum storage capacity of 170 acre-feet, and collects water from a drainage area of 1 square miles. Completed in 1934, 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 08/12/2022.
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 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 | Clear Creek |
| Nearest City | Idaho Springs |
| River/Stream | Fall River-tr |
| Coordinates | 39.81729, -105.69325 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 18 ft |
| Dam Height | 18 ft |
| Dam Length | 440 ft |
| Year Completed | 1934 (92 years old) |
Storage & Hydraulics
| NID Storage | 170 acre-ft |
| Max Storage | 170 acre-ft |
| Normal Storage | 108 acre-ft |
| Surface Area | 12 acres |
| Drainage Area | 1 sq mi |
| Max Discharge | 560 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Irrigation |
| Owner | AGRICULTURAL DITCH & RESERVOIR COMPANY (ACKER, PET |
| Owner Type | Private |
| Hazard Classification | High |
| Condition Assessment | Not Rated |
| Last Inspection | 08/12/2022 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CO00191 |
| Federal ID | CO00191 |
| More Info | State Dam Safety Program |