Green Hollow Creek Dam Reservoir Report

Last Updated: December 5, 2025

Green Hollow Creek Dam, located in Gallatin Gateway, Montana, is a private-owned structure designed for recreation purposes along the Green Hollow Creek.


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Summary

Completed in 1990, this earth dam stands at a height of 45 feet with a hydraulic height of 38 feet and a length of 680 feet. With a storage capacity of 300 acre-feet and a surface area of 15 acres, the dam serves as a popular spot for outdoor activities such as fishing and boating.

Managed by the Montana Department of Natural Resources and Conservation (DNRC), Green Hollow Creek Dam is regulated, inspected, and enforced by the state to ensure safety and compliance with standards. Despite being classified as a high hazard potential structure, the dam is assessed to be in satisfactory condition as of June 2018. In case of emergencies, the dam's Emergency Action Plan (EAP) is regularly updated and maintained to meet guidelines for risk management and mitigation.

With its picturesque location and recreational value, Green Hollow Creek Dam offers a tranquil escape for water resource and climate enthusiasts. Boasting a rich history and serving as a vital part of the local ecosystem, this dam stands as a testament to the importance of responsible water management and environmental stewardship in the face of changing climatic conditions.

Year Completed

1990

Dam Length

680

Dam Height

45

River Or Stream

GREEN HOLLOW CREEK

Primary Dam Type

Earth

Surface Area

15

Hydraulic Height

38

Drainage Area

4.4

Nid Storage

300

Hazard Potential

High

Foundations

Soil

Nid Height

45
       
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.