Bradshaw Detention Dam #3 Reservoir Report

Last Updated: December 5, 2025

Located in Custer, Idaho, the Bradshaw Detention Dam #3 is a Federal-owned structure designed to mitigate flood risks along the Bradshaw Gulch.


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Summary

Managed by the Bureau of Land Management, this gravity dam stands at a structural height of 33 feet and has a hydraulic height of 30 feet. With a storage capacity of 20 acre-feet, the dam serves the primary purpose of flood risk reduction, safeguarding the surrounding rural ranch area.

The dam features an uncontrolled spillway with a width of 2 feet and a maximum discharge of 271 cubic feet per second. Despite its low hazard potential, the dam has a moderate risk assessment rating of 3, highlighting the importance of regular inspections and risk management measures. While the last inspection took place in July 2012, the dam is scheduled for inspections every 5 years to ensure its safety and functionality as a vital water resource infrastructure in the region.

Water resource and climate enthusiasts will appreciate the strategic location of the Bradshaw Detention Dam #3 and its contribution to maintaining water security in the area. With a focus on flood risk reduction and a history of Federal ownership and oversight, this dam exemplifies the careful planning and management essential for sustainable water resource infrastructure in the face of changing climate patterns.

Dam Length

374

River Or Stream

BRADSHAW GULCH

Primary Dam Type

Gravity

Surface Area

3

Hydraulic Height

30

Drainage Area

1.5

Nid Storage

20

Structural Height

33

Hazard Potential

Low

Foundations

Unlisted/Unknown

Nid Height

33
       
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.