Pierce is an earth dam located in Carbon County, Wyoming, built in 1918. It carries a Significant hazard potential classification and has a fair condition assessment.
Dam profile
NID height · 30 ft30 ft tall and 4,500 ft long, taller than 68% 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 Pierce
The primary purpose of Pierce is irrigation. The dam stores and diverts water for agricultural irrigation, supporting farming operations in the surrounding area. The dam is owned by Pierce Reservoir Incorporated (state). It impounds the Rock Creek Offstream near Como Bluffs Fish Hatchery.
The dam stands 30 feet tall and stretches 4,500 feet across, creates a reservoir covering 199 acres, has a maximum storage capacity of 3,711 acre-feet, and collects water from a drainage area of 19 square miles. Completed in 1918, the structure is over a century old.
This dam has a significant hazard potential classification, meaning that a failure could cause significant economic damage — flooding roads, bridges, or property downstream — but is not expected to result in loss of life. Its condition is rated fair — the dam has minor deficiencies that are being addressed or do not pose an immediate safety threat. An emergency action plan is in place for this dam. The most recent inspection on record was 08/22/2023.
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Location
| State | Wyoming |
| County | Carbon |
| Nearest City | Como Bluffs Fish Hatchery |
| River/Stream | Rock Creek Offstream |
| Coordinates | 41.69083, -106.08694 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 30 ft |
| Dam Height | 30 ft |
| Dam Length | 4,500 ft |
| Year Completed | 1918 (108 years old) |
Storage & Hydraulics
| NID Storage | 3,711 acre-ft |
| Max Storage | 3,711 acre-ft |
| Normal Storage | 3,206 acre-ft |
| Surface Area | 199 acres |
| Drainage Area | 19 sq mi |
| Max Discharge | 1,323 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Irrigation |
| Owner | Pierce Reservoir Incorporated |
| Owner Type | State |
| Hazard Classification | Significant |
| Condition Assessment | Fair |
| Last Inspection | 08/22/2023 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | WY00357 |
| Federal ID | WY00357 |
| More Info | State Dam Safety Program |