Big Donaldson Reservoir Report
Nearby: Fowler Green Cabin
Last Updated: December 5, 2025
Big Donaldson is a privately owned earth dam located in Johnson County, Wyoming, near the city of Clearmont.
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Summary
Completed in 1973, this dam serves multiple purposes, including fire protection, stock, and small fish pond management. With a height of 22 feet and a length of 475 feet, Big Donaldson has a storage capacity of 92 acre-feet and covers a surface area of 10 acres. The dam is regulated by the State of Wyoming and is inspected regularly to ensure its structural integrity.
Despite being classified as a low hazard potential structure with a fair condition assessment, Big Donaldson poses a moderate risk according to a recent assessment. The dam is equipped with an uncontrolled spillway with a width of 90 feet, and there are no outlet gates associated with the structure. The last inspection of Big Donaldson took place in July 2018, and it is scheduled for inspection every 5 years to evaluate its safety and maintenance needs. The dam is located on the Double Crossing Draw river or stream and is situated within the jurisdiction of the State of Wyoming.
Overall, Big Donaldson is an essential infrastructure for water resource management in the region, providing valuable services for fire protection, livestock, and recreational activities. As climate change continues to impact water resources, it is crucial to monitor and maintain structures like Big Donaldson to ensure the safety and sustainability of water supplies in the area. With its strategic location and functional design, Big Donaldson plays a critical role in water management efforts in Johnson County, Wyoming.
Year Completed |
1973 |
Dam Length |
475 |
Dam Height |
22 |
River Or Stream |
DOUBLE CROSSING DRAW |
Primary Dam Type |
Earth |
Surface Area |
10 |
Hydraulic Height |
17 |
Nid Storage |
92 |
Structural Height |
22 |
Outlet Gates |
None |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
22 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Powder River At Arvada
|
156cfs |
Piney Creek At Kearny
|
113cfs |
Wild Horse Creek Near Arvada
|
0cfs |
Clear Creek Near Buffalo
|
12cfs |
Rock Creek Near Buffalo
|
70cfs |
Clear Creek Near Arvada
|
256cfs |
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.
Big Donaldson