Lyle Nelson #1 Reservoir Report

Last Updated: December 5, 2025

Lyle Nelson #1 is a private earth dam located in McCone, Montana, along the TR-North Fork Rock Creek.


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Summary

Built in 1969, this dam serves multiple purposes, including fire protection, stock watering, and creating a small fish pond. With a height of 15 feet and a length of 200 feet, it has a storage capacity of 54 acre-feet and a normal storage of 28 acre-feet. The dam is regulated by the Montana Department of Natural Resources and Conservation, ensuring it meets state permitting, inspection, and enforcement requirements.

This low-hazard dam has not been rated for its condition assessment, but it is regularly monitored for any potential risks. Despite its age, there have been no reported modifications or significant incidents associated with Lyle Nelson #1. The dam does not have an Emergency Action Plan in place, but it is reassuring to know that it is equipped to handle emergencies as needed. With its strategic location and purposeful design, Lyle Nelson #1 stands as a testament to effective water resource management in Montana.

As an essential component of the local water infrastructure, Lyle Nelson #1 plays a crucial role in ensuring water availability for firefighting, livestock, and recreational purposes in the area. With its modest storage capacity and low-hazard potential, this dam exemplifies the importance of maintaining and regulating water resources to meet various community needs. For water resource and climate enthusiasts, Lyle Nelson #1 serves as a fascinating case study in sustainable water management practices and the harmonious coexistence of human development and ecological conservation in Montana.

Year Completed

1969

Dam Length

200

Dam Height

15

River Or Stream

TR-NORTH FORK ROCK CREEK

Primary Dam Type

Earth

Hydraulic Height

15

Nid Storage

54

Hazard Potential

Low

Nid Height

15
       
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.