Big Sky County Wastewater Pond1 Reservoir Report

Last Updated: December 5, 2025

Big Sky County Wastewater Pond1, located in Gallatin, Montana, is a critical offstream water resource managed by the local government.


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Summary

This Earth dam, completed in 1997, stands at a height of 23.5 feet and has a storage capacity of 184.5 acre-feet. Despite its high hazard potential, the dam is currently rated as "Not Rated" in terms of condition assessment.

The dam's primary purpose is listed as "Other," and it is regulated by the Montana Department of Environmental Quality (DEQ). With state permitting, inspection, and enforcement in place, the dam is subject to regular oversight to ensure public safety. Although the last inspection took place in 2007, the risk assessment for the dam is moderate, indicating the need for continued monitoring and potential risk management measures in the future.

As a key component of the local water infrastructure, Big Sky County Wastewater Pond1 plays a crucial role in wastewater management for the region. With its strategic location and significant storage capacity, the dam serves as a vital resource for water supply and flood control. Continued attention to maintenance and oversight will be essential to ensure the long-term safety and functionality of this important water resource in Big Sky County.

Year Completed

1997

Dam Length

1760

Dam Height

23.5

River Or Stream

OFFSTREAM

Primary Dam Type

Earth

Hydraulic Height

20

Nid Storage

184.5

Structural Height

23.5

Hazard Potential

High

Foundations

Rock, Soil

Nid Height

24
       
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.