Lockie #6 Reservoir Report

Last Updated: December 6, 2025

Lockie #6 is a privately owned earth dam located in Miles City, Montana, along the West Fork Moon Creek.


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Summary

Completed in 1975 by the USDA NRCS, this dam serves multiple purposes including fire protection, stock watering, and creating a small fish pond. With a height of 21 feet and a length of 420 feet, Lockie #6 has a storage capacity of 146 acre-feet and a drainage area of 2.19 square miles. The dam has a low hazard potential and is currently rated as being in a moderate risk category.

Despite being uncontrolled, Lockie #6 has a spillway width of 50 feet to manage maximum discharges of up to 330 cubic feet per second. The dam is under the regulatory jurisdiction of the DNRC and is subject to state permitting, inspection, and enforcement. While the condition assessment of Lockie #6 is currently listed as "Not Rated," the risk assessment categorizes it as having a moderate risk level. With its strategic location and multi-purpose design, Lockie #6 plays a crucial role in water resource management and climate resilience efforts in the region.

Year Completed

1975

Dam Length

420

Dam Height

21

River Or Stream

WEST FORK MOON CREEK

Primary Dam Type

Earth

Hydraulic Height

21

Drainage Area

2.19

Nid Storage

146

Hazard Potential

Low

Nid Height

21
       
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.