Jeffers #1 Reservoir Report

Last Updated: December 5, 2025

Jeffers #1 is a privately owned earth dam located in Benteen, Big Horn County, Montana.


°F

°F

mph

Wind

%

Humidity

Summary

Built in 1959 by the USDA NRCS, this dam serves multiple purposes including fire protection, stock watering, and as a small fish pond. The dam has a height of 26 feet and a storage capacity of 215 acre-feet, with a normal storage level of 71 acre-feet.

Situated on the TR-Little Big Horn River, Jeffers #1 is regulated by the Montana Department of Natural Resources and Conservation (DNRC) and is subject to state permitting, inspection, and enforcement. The dam has a low hazard potential and a moderate risk assessment rating of 3. With a maximum discharge capacity of 250 cubic feet per second and an uncontrolled spillway width of 20 feet, the dam is designed to safely manage excess water flow during periods of high rainfall or snowmelt.

Water resource and climate enthusiasts will appreciate the strategic design and multi-functional use of Jeffers #1. With its important role in providing water for firefighting, livestock, and fish habitat, this dam represents a vital piece of infrastructure in the region. Its location in the beautiful Montana landscape adds to its significance as a key component of water resource management in the area.

Year Completed

1959

Dam Length

150

Dam Height

26

River Or Stream

TR-LITTLE BIG HORN RIVER

Primary Dam Type

Earth

Hydraulic Height

26

Drainage Area

3.13

Nid Storage

215

Hazard Potential

Low

Nid Height

26
       
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.