Grass Valley
Grass Valley is an earth dam located in Garfield County, Colorado, built in 1892. It carries a High hazard potential classification and has a unsatisfactory condition assessment.
About Grass Valley
The primary purpose of Grass Valley is irrigation. The dam stores and diverts water for agricultural irrigation, supporting farming operations in the surrounding area. The dam is owned by Silt Water Conservancy District (public utility). It impounds the Harvey Gap near Silt.
The dam stands 61 feet tall and stretches 800 feet across, creates a reservoir covering 320 acres, has a maximum storage capacity of 6,111 acre-feet, and collects water from a drainage area of 2 square miles. Completed in 1892, the structure is over a century 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 unsatisfactory, indicating serious safety deficiencies exist that require immediate attention or remedial action. An emergency action plan is in place for this dam. The most recent inspection on record was 04/06/2022.
At 61 feet, this dam is taller than 95% 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 | Garfield |
| Nearest City | Silt |
| River/Stream | Harvey Gap |
| Coordinates | 39.60667, -107.66057 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 61 ft |
| Dam Height | 61 ft |
| Dam Length | 800 ft |
| Year Completed | 1892 (134 years old) |
Storage & Hydraulics
| NID Storage | 6,111 acre-ft |
| Max Storage | 6,111 acre-ft |
| Normal Storage | 5,060 acre-ft |
| Surface Area | 320 acres |
| Drainage Area | 2 sq mi |
| Max Discharge | 542 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Irrigation |
| Owner | SILT WATER CONSERVANCY DISTRICT |
| Owner Type | Public Utility |
| Hazard Classification | High |
| Condition Assessment | Unsatisfactory |
| Last Inspection | 04/06/2022 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CO00693 |
| Federal ID | CO00693 |
| More Info | State Dam Safety Program |