Nelson Irrigation (Wheatland) Reservoir Report

Last Updated: December 5, 2025

Nelson Irrigation (Wheatland) is a privately owned irrigation structure located in Wheatland, Montana, along Hopley Creek.


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Summary

Built in 1956 by the USDA NRCS, this earth dam stands at a height of 25 feet and has a storage capacity of 117 acre-feet, with a maximum discharge of 300 cubic feet per second. The dam serves the primary purpose of irrigation, supporting agricultural activities in the region.

Managed by the Montana Department of Natural Resources and Conservation (DNRC), Nelson Irrigation (Wheatland) is regulated, permitted, inspected, and enforced by state authorities, ensuring its safe and efficient operation. With a low hazard potential and a condition assessment of "Not Rated", the dam poses minimal risk to the surrounding area. Although lacking in certain emergency preparedness measures such as an Emergency Action Plan (EAP), the structure meets regulatory guidelines and contributes to water resource management in the region.

Situated in Congressional District 00 of Montana, Nelson Irrigation (Wheatland) plays a vital role in sustaining agricultural productivity and water availability in the area. With a rich history dating back to its construction in the mid-20th century, this irrigation infrastructure continues to support local farmers and contribute to the overall water resource management efforts in the state.

Year Completed

1956

Dam Length

500

Dam Height

25

River Or Stream

HOPLEY CREEK

Primary Dam Type

Earth

Hydraulic Height

25

Drainage Area

46.88

Nid Storage

117

Hazard Potential

Low

Nid Height

25
       
Seasonal Comparison

Weather Forecast

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.