Antelope Dam Reservoir Report
Nearby: Bridge Dam Donlin Detention Dam
Last Updated: December 13, 2025
Antelope Dam, located in Natrona, Wyoming, was completed in 1956 and is owned and regulated by the Bureau of Land Management.
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Summary
The primary purpose of this gravity dam is debris control, specifically on the Antelope Draw river or stream. With a hydraulic height of 20 feet and a structural height of 25 feet, the dam has a normal storage capacity of 42 acre-feet and a maximum storage capacity of 96.9 acre-feet. The dam spans 482 feet in length and covers a surface area of 7.6 acres, serving as a vital resource for water management in the region.
Managed by the Bureau of Land Management, Antelope Dam has a low hazard potential and is assessed to be in fair condition as of the last inspection in July 2017. The dam features an uncontrolled spillway with a width of 2 feet and a maximum discharge capacity of 300 cubic feet per second. While the dam has not been modified in recent years and does not have outlet gates, it plays a crucial role in mitigating flood risks and ensuring water security in the area. Despite its moderate risk assessment rating, Antelope Dam continues to be a key component of water resource management efforts in Wyoming.
With Liz Cheney representing the district, Antelope Dam stands as a testament to the Bureau of Land Management's commitment to safe and effective dam operations. The dam's sturdy buttress and stone core construction, along with its regulated state jurisdiction and inspection protocols, highlight the importance of proactive infrastructure management in the face of changing climate patterns. As a gravity dam designed to withstand the forces of nature, Antelope Dam remains a cornerstone of water conservation and climate resilience initiatives in the region, safeguarding communities and ecosystems for generations to come.
Year Completed |
1956 |
Dam Length |
482 |
River Or Stream |
ANTELOPE DRAW |
Primary Dam Type |
Gravity |
Surface Area |
7.6 |
Hydraulic Height |
20 |
Drainage Area |
3.5 |
Nid Storage |
96.9 |
Structural Height |
25 |
Outlet Gates |
None |
Hazard Potential |
Low |
Foundations |
Unlisted/Unknown |
Nid Height |
25 |
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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