Underdal #2 Reservoir Report
Nearby: Underdal #1 Gouchenour
Last Updated: December 6, 2025
Underdal #2 is a privately owned dam located in Loma, Montana, along the Timber Coulee river.
°F
°F
mph
Wind
%
Humidity
Summary
Completed in 1938, this earth dam stands at a height of 25 feet and has a storage capacity of 90 acre-feet, primarily for recreational purposes. The dam is under state jurisdiction and regulation by the Department of Natural Resources and Conservation (DNRC), with state permitting, inspection, and enforcement in place.
With a low hazard potential and no current condition assessment rating, Underdal #2 provides a picturesque setting for outdoor activities in Toole County. While the dam has not been rated for its condition, it remains a key feature in the local landscape and an important site for water resource and climate enthusiasts to explore. As a part of the Omaha District, the dam contributes to the recreational opportunities in the area and is a significant landmark in the region.
Although the dam does not fall under the purview of the US Army Corps of Engineers, its presence along the Timber Coulee river adds to the scenic beauty and recreational offerings in the vicinity. With its historical significance dating back to the late 1930s, Underdal #2 stands as a testament to the engineering feats of the past and continues to be a valuable resource for the community and visitors alike.
Year Completed |
1938 |
Dam Length |
300 |
Dam Height |
25 |
River Or Stream |
TIMBER COULEE |
Primary Dam Type |
Earth |
Hydraulic Height |
25 |
Nid Storage |
90 |
Hazard Potential |
Low |
Nid Height |
25 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Marias River Near Chester Mt
|
249cfs |
Teton River Near Dutton Mt
|
83cfs |
Marias River Near Shelby Mt
|
305cfs |
Lake Creek Near Power Mt
|
30cfs |
Marias River Near Loma Mt
|
335cfs |
Missouri River At Fort Benton Mt
|
4720cfs |
Dam Data Reference
Condition Assessment
SatisfactoryNo 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
HighDams 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.
North Bootlegger - Lake Elwell - USBR
Island Area - Lake Elwell - USBR
Sanford Park - Tiber Reservoir (Lake Elwell)
Sanford Park - Lake Elwell - USBR
Underdal #2