Zezas No. 1 Reservoir Report
Nearby: Zezas Zezas Irrigation
Last Updated: December 13, 2025
Zezas No.
°F
°F
mph
Wind
%
Humidity
Summary
1 is a privately owned earth dam located in Johnson, Wyoming, along the Gammon Draw stream. Built in 1968 for fire protection, stock, and small fish pond purposes, this dam stands at 27 feet in height with a length of 611 feet, providing a storage capacity of 67 acre-feet. Despite its low hazard potential, the dam has been rated as having poor structural condition, as assessed in July 2019.
Owned and regulated by the State of Wyoming, Zezas No. 1 is subject to regular inspections, enforcement, and permitting to ensure its safety and compliance with state regulations. The dam features an uncontrolled spillway with a width of 40 feet, serving as a safety feature in case of overflow events. The surrounding area has a surface area of 6 acres and a drainage area of 0, making it a critical water resource for the region.
With its strategic location and multiple purposes, Zezas No. 1 plays a crucial role in providing essential water resources for fire protection, livestock, and recreational activities. Despite its moderate risk rating, efforts are needed to improve the structural condition of the dam to ensure its long-term reliability and safety for the community and the environment.
Year Completed |
1968 |
Dam Length |
611 |
Dam Height |
24 |
River Or Stream |
GAMMON DRAW |
Primary Dam Type |
Earth |
Surface Area |
6 |
Hydraulic Height |
19 |
Nid Storage |
67 |
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.
Zezas No. 1