Tarzan Reservoir Report

Last Updated: December 5, 2025

Tarzan is a privately owned earth dam located in Blaine, Montana, along the Bullwhacker Creek.


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Summary

Completed in 1973, this dam serves multiple purposes including fire protection, stock, and small fish pond. With a height of 38 feet and a storage capacity of 78 acre-feet, Tarzan plays a crucial role in water resource management in the area.

Managed by the Montana Department of Natural Resources and Conservation (DNRC), Tarzan is regulated by the state and undergoes regular inspections to ensure its structural integrity and safety. Despite its low hazard potential, the dam has not been rated for its condition assessment, indicating the need for further evaluation and potentially the development of an Emergency Action Plan (EAP) to address any unforeseen risks.

Situated in a remote location and surrounded by natural beauty, Tarzan offers a glimpse into the delicate balance between water resources and climate in Montana. As water resource and climate enthusiasts, exploring the role of dams like Tarzan in the region provides valuable insights into the challenges and opportunities for sustainable water management in a changing climate.

Year Completed

1973

Dam Length

240

Dam Height

38

River Or Stream

TR-BULLWHACKER CREEK

Primary Dam Type

Earth

Hydraulic Height

38

Nid Storage

78

Hazard Potential

Low

Nid Height

38
       
Seasonal Comparison

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Dam Data Reference

Condition Assessment

Satisfactory
No 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

High
Dams 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.