Middle No. 1 Reservoir Report
Nearby: Ketelsen #9-219-2 Dull
Last Updated: December 17, 2025
Middle No.
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Summary
1, located in Converse, Wyoming, is a privately owned Earth dam built in 1962 for irrigation purposes on Middle Cow Creek. Standing at a height of 17 feet with a hydraulic height of 12 feet, this dam has a storage capacity of 246 acre-feet and a surface area of 20 acres. Despite its low hazard potential, the dam's condition assessment in 2019 was deemed unsatisfactory, indicating a need for maintenance and improvements to ensure its safety and functionality.
With a spillway width of 105 feet and an uncontrolled spillway type, Middle No. 1 has one slide gate for outlet control. Although it has a moderate risk assessment rating of 3, the dam has not undergone any modifications or updates in recent years. It is important for water resource and climate enthusiasts to monitor the condition of Middle No. 1 and advocate for necessary repairs and risk management measures to prevent any potential hazards or failures in the future. The dam is under the jurisdiction and regulation of the State Engineer's Office, highlighting the importance of state oversight in ensuring the safety and integrity of water infrastructure in Wyoming.
Year Completed |
1962 |
Dam Length |
1180 |
Dam Height |
17 |
River Or Stream |
MIDDLE COW CREEK |
Primary Dam Type |
Earth |
Surface Area |
20 |
Hydraulic Height |
12 |
Nid Storage |
246 |
Structural Height |
17 |
Outlet Gates |
Slide (sluice gate) - 1 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
17 |
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.
Middle No. 1