Rattlesnake #2 Reservoir Report
Nearby: J Witkowski #1 Virgil Larson
Last Updated: December 6, 2025
Rattlesnake #2 is a privately owned earth dam located in Wibaux, Montana, along TR-Beaver Creek.
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Summary
Built in 1965 by the USDA NRCS, this dam serves multiple purposes including fire protection, stock watering, and small fish pond creation. With a height of 15 feet and a length of 300 feet, the dam has a storage capacity of 137 acre-feet and a drainage area of 2.63 square miles. The spillway type is uncontrolled with a width of 20 feet, and the maximum discharge capacity is 200 cubic feet per second.
Despite being classified as having a low hazard potential, Rattlesnake #2 is considered to have a moderate risk level (3) based on a risk assessment. The condition assessment is currently listed as "Not Rated," and there is no information available regarding the last inspection date or inspection frequency. While the emergency action plan (EAP) status is unknown, it is noted that the dam does not meet USACE guidelines and has not had inundation maps prepared. Overall, Rattlesnake #2 presents an intriguing case study for water resource and climate enthusiasts, as it showcases the unique challenges and complexities associated with managing and maintaining dams in rural Montana.
Year Completed |
1965 |
Dam Length |
300 |
Dam Height |
15 |
River Or Stream |
TR-BEAVER CREEK |
Primary Dam Type |
Earth |
Hydraulic Height |
15 |
Drainage Area |
2.63 |
Nid Storage |
137 |
Hazard Potential |
Low |
Nid Height |
15 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Yellowstone River At Glendive Mt
|
6000cfs |
Beaver Creek Nr Trotters
|
0cfs |
Little Missouri River At Marmarth
|
12cfs |
Deep Creek Nr Amidon
|
0cfs |
Little Missouri River At Medora
|
64cfs |
Powder River Near Locate Mt
|
231cfs |
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.
Rattlesnake #2