Flagstone Reservoir Report
Nearby: Bedstead No. 2 Knife Edge
Last Updated: December 5, 2025
Flagstone is a federal-owned dam located in Washakie, Wyoming, with a primary purpose of providing fire protection, stock, or a small fish pond.
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Summary
Built in 1965 by designer Walter J Pilch, the dam is an earth structure with a core made of stone and a foundation of soil. Standing at a height of 27 feet and spanning 248 feet in length, Flagstone has a storage capacity of 48 acre-feet and a surface area of 4 acres.
Despite being categorized as having a low hazard potential and fair condition assessment, Flagstone is regulated and inspected by the State of Wyoming to ensure its safety and compliance. The dam is equipped with an uncontrolled spillway, with a spillway width of 30 feet. Although the drainage area associated with the dam is listed as 0, the dam serves as a crucial resource for water management and agricultural purposes in the region. As climate change continues to impact water resources, the management and upkeep of dams like Flagstone become increasingly important for sustainable water use and environmental protection.
In the event of an emergency, the dam has protocols in place for risk management and emergency response, with inspections occurring every 5 years to assess its condition and readiness. With its moderate risk assessment and location in an area prone to natural disasters, Flagstone serves as a vital infrastructure for water supply and ecosystem support, highlighting the intersection of water resource management and climate resilience in the face of changing environmental conditions.
Year Completed |
1965 |
Dam Length |
248 |
Dam Height |
27 |
River Or Stream |
FLAGSTONE DRAW |
Primary Dam Type |
Earth |
Surface Area |
4 |
Hydraulic Height |
22 |
Nid Storage |
48 |
Structural Height |
27 |
Outlet Gates |
None |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
27 |
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.
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