Wiley Reservoir Report
Nearby: Sage Creek C. Thomsen
Last Updated: March 14, 2026
Wiley is a privately owned irrigation dam located in Park County, Wyoming, near the city of Byron.
Summary
Built in 1971 by designer Lee Graham, this earth dam on Sage Creek stands at a height of 31 feet and has a storage capacity of 1365 acre-feet. Despite its low hazard potential, the dam is currently in poor condition, as per the last inspection in June 2019.
With a surface area of 331 acres and a drainage area of zero, Wiley serves primarily for irrigation purposes. Its spillway type is uncontrolled, with a width of 6 feet. Although the dam has not been modified in recent years, it is subject to regular state regulation, inspection, and enforcement. Its location in a congressional district represented by Liz Cheney underscores its importance in the water resource management of the region.
While Wiley may have a moderate risk assessment, its role in supporting agriculture and water supply in the area cannot be overlooked. As a key structure on Sage Creek, it highlights the intersection of water resource management and climate resilience. With its historical significance and ongoing regulatory oversight, Wiley continues to be a focal point for water resource and climate enthusiasts interested in sustainable infrastructure development.
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15-Day Weather Outlook
Year Completed |
1971 |
Dam Length |
1006 |
Dam Height |
31 |
River Or Stream |
SAGE CREEK |
Primary Dam Type |
Earth |
Surface Area |
331 |
Hydraulic Height |
26 |
Nid Storage |
1365 |
Structural Height |
31 |
Outlet Gates |
None |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
31 |
Seasonal Comparison
5-Day Hourly Forecast Detail
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.
Wiley