Monkey Cowboy Reservoir Report
Nearby: Anna Total Station
Last Updated: December 13, 2025
Monkey Cowboy is a private earth dam located in Johnson, Wyoming, along the Vishnu Draw river.
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Summary
Built in 2007 by designer Hugh Lowham, this dam serves multiple purposes, including fire protection, stock watering, and small fish pond management. With a height of 33 feet and a length of 720 feet, Monkey Cowboy has a storage capacity of 84 acre-feet and a surface area of 6 acres.
Despite its low hazard potential and fair condition assessment, Monkey Cowboy is regulated by the Wyoming State Engineer's Office, which ensures that the dam meets all state permitting, inspection, and enforcement requirements. The dam's spillway type is uncontrolled, with a width of 65 feet, and it has a valve outlet gate for water release. The risk assessment for Monkey Cowboy is moderate, with a designated emergency action plan in place and a regular inspection frequency of 5 years to maintain its safety and functionality.
Located on a local road in Johnson County, Monkey Cowboy is a vital water resource for the surrounding area, providing essential services for both agricultural and environmental purposes. Its strategic design and efficient operation make it a key player in water management and conservation efforts in Wyoming, showcasing the importance of sustainable infrastructure in the face of changing climate conditions.
Year Completed |
2007 |
Dam Length |
720 |
Dam Height |
33 |
River Or Stream |
VISHNU DRAW |
Primary Dam Type |
Earth |
Surface Area |
6 |
Hydraulic Height |
28 |
Drainage Area |
0.14 |
Nid Storage |
84 |
Structural Height |
36 |
Outlet Gates |
Valve - 1 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
36 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Clear Creek Near Buffalo
|
18cfs |
Powder River At Sussex
|
144cfs |
Powder River At Arvada
|
180cfs |
Wild Horse Creek Near Arvada
|
0cfs |
Nf Powder River Below Pass Creek
|
50cfs |
Rock Creek Near Buffalo
|
70cfs |
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.
Monkey Cowboy