Clamhopper #1 Reservoir Report

Last Updated: December 5, 2025

Clamhopper #1, also known as Two Crow #1, is a privately owned earth dam located in Petroleum County, Montana.


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Summary

Built in 1960, this dam has a primary purpose of fire protection, stock, or small fish pond. With a height of 20 feet and a length of 200 feet, Clamhopper #1 has a storage capacity of 51 acre-feet and a normal storage level of 26 acre-feet. Situated on TR-DRAG CREEK, this dam is regulated by the Montana Department of Natural Resources and Conservation (DNRC) and is subject to state permitting, inspection, and enforcement.

Despite its low hazard potential and current "Not Rated" condition assessment, Clamhopper #1's emergency action plan status, risk assessment, and management measures are not available. The dam, managed by a private entity, does not fall under federal agency ownership or funding. Its location in a remote area with no nearby city underscores the importance of proper maintenance and monitoring to ensure its effectiveness in providing fire protection and sustaining water resources for stock or small fish pond purposes. As a crucial component of the local water infrastructure, continued attention to Clamhopper #1 is essential for the community and environment it serves.

Year Completed

1960

Dam Length

200

Dam Height

20

River Or Stream

TR-DRAG CREEK

Primary Dam Type

Earth

Hydraulic Height

20

Nid Storage

51

Hazard Potential

Low

Nid Height

20
       
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.