Pierce Reservoir Report
Nearby: Little Pierce Lace
Last Updated: December 5, 2025
Pierce is a historic earth dam located in Carbon County, Wyoming, with a primary purpose of irrigation.
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Summary
Built in 1918, it stands at a height of 30 feet and has a hydraulic height of 25 feet. This dam holds a storage capacity of 3,711 acre-feet, with a normal storage level of 3,206 acre-feet, serving the Rock Creek Offstream in the Como Bluffs Fish Hatchery area. With a surface area of 199 acres and a drainage area of 19.5 square miles, Pierce plays a crucial role in water resource management in the region.
Despite its age, Pierce is in fair condition according to the latest assessment in August 2018. It has a high hazard potential due to its location and purpose, but the risk assessment deems it as moderate (3). The dam has an uncontrolled spillway with a width of 6 feet and two other controlled outlet gates. While it is state-regulated and inspected regularly, there are no associated structures and the dam is owned by the state of Wyoming. With Liz Cheney as the Congressional representative overseeing this area, Pierce remains an essential component of the local irrigation infrastructure.
Water resource and climate enthusiasts will find Pierce to be a fascinating example of early 20th-century engineering, serving as a testament to the importance of water management in the arid landscapes of Wyoming. The dam's location in the Sacramento District underlines its significance in maintaining water supply for agricultural activities in the region. As discussions around climate change and water scarcity intensify, understanding the role of structures like Pierce in ensuring sustainable water use becomes increasingly relevant. The dam's history, design, and operational details offer valuable insights into the intersection of water resources, infrastructure, and environmental conservation.
Year Completed |
1918 |
Dam Length |
4500 |
Dam Height |
30 |
River Or Stream |
ROCK CREEK OFFSTREAM |
Primary Dam Type |
Earth |
Surface Area |
199 |
Hydraulic Height |
25 |
Drainage Area |
19.5 |
Nid Storage |
3711 |
Structural Height |
30 |
Outlet Gates |
Other Controlled - 2 |
Hazard Potential |
High |
Foundations |
Soil |
Nid Height |
30 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Dam Data Reference
Condition Assessment
SatisfactoryNo existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable state or federal regulatory criteria or tolerable risk guidelines.
Fair
No existing dam safety deficiencies are recognized for normal operating conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action. Note: Rare or extreme event is defined by the regulatory agency based on their minimum
Poor A dam safety deficiency is recognized for normal operating conditions which may realistically occur. Remedial action is necessary. POOR may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency. Investigations and studies are necessary.
Unsatisfactory
A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
Not Rated
The dam has not been inspected, is not under state or federal jurisdiction, or has been inspected but, for whatever reason, has not been rated.
Not Available
Dams for which the condition assessment is restricted to approved government users.
Hazard Potential Classification
HighDams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.
Significant
Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environment damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be in areas with population and significant infrastructure.
Low
Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner's property.
Undetermined
Dams for which a downstream hazard potential has not been designated or is not provided.
Not Available
Dams for which the downstream hazard potential is restricted to approved government users.
Pierce