Upper Stillwater is an earth dam located in Garfield County, Colorado, built in 1965. It carries a Low hazard potential classification and has a satisfactory condition assessment.
Dam profile
NID height · 40 ft40 ft tall and 275 ft long, taller than 86% of U.S. dams with a recorded height. Height is drawn to scale against a two-story house, about 25 ft; the profile is a generic embankment section and the water level is illustrative.
About Upper Stillwater
The primary purpose of Upper Stillwater is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Colorado Parks and Wildlife (state). It impounds the Bear River near Yampa.
The dam stands 40 feet tall and stretches 275 feet across, creates a reservoir covering 53 acres, has a maximum storage capacity of 1,096 acre-feet, and collects water from a drainage area of 22 square miles. Completed in 1965, the structure is well into its service life at over 50 years old.
This dam has a low hazard potential classification, meaning that failure would cause minimal damage, limited primarily to the dam owner's property, with no expected loss of life. Its condition is rated satisfactory, indicating no existing or potential dam safety deficiencies are recognized. The most recent inspection on record was 08/22/2019.
At 40 feet, this dam is taller than 86% of dams nationwide.
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Location
| State | Colorado |
| County | Garfield |
| Nearest City | Yampa |
| River/Stream | Bear River |
| Coordinates | 40.04420, -107.07250 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 40 ft |
| Dam Height | 28 ft |
| Dam Length | 275 ft |
| Year Completed | 1965 (61 years old) |
Storage & Hydraulics
| NID Storage | 1,096 acre-ft |
| Max Storage | 1,096 acre-ft |
| Normal Storage | 620 acre-ft |
| Surface Area | 53 acres |
| Drainage Area | 22 sq mi |
| Max Discharge | 2,150 cfs |
| Spillway Type | None |
Ownership & Safety
| Purpose | Recreation |
| Owner | Colorado Parks and Wildlife |
| Owner Type | State |
| Hazard Classification | Low |
| Condition Assessment | Satisfactory |
| Last Inspection | 08/22/2019 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | CO01031 |
| Federal ID | CO01031 |
| More Info | State Dam Safety Program |