Louisa Creek Reservoir Report

Last Updated: December 19, 2025

Louisa Creek is a privately owned water resource located in Owyhee, Idaho, with a dam completed in 1931 for purposes other than irrigation or drinking water supply.


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Summary

The dam is a concrete structure with a multi-arch core type and stands at a height of 41 feet, with a hydraulic height of 38 feet. The reservoir has a storage capacity of 175 acre-feet and covers a surface area of 9 acres, serving a drainage area of 8.2 square miles.

Despite its low hazard potential, Louisa Creek's dam is currently in poor condition, with a risk assessment rating of moderate. The last inspection in June 2019 highlighted the need for improvement, with an inspection frequency of 4 years. The dam features an uncontrolled spillway with a width of 3 feet and a maximum discharge of 30 cubic feet per second. While the risk management measures and emergency action plan status are unknown, the dam's location and structural specifications make it a valuable resource for water resource and climate enthusiasts interested in Idaho's hydrological infrastructure.

Overall, Louisa Creek represents a historic and functional water resource in Idaho, standing as a testament to early 20th-century engineering and serving as a vital component of the local watershed. With its unique design and operational characteristics, the dam provides a fascinating glimpse into the intersection of human intervention and natural water systems, making it a point of interest for those interested in water resource management and climate resilience in the region.

Year Completed

1931

Dam Length

40

Dam Height

41

River Or Stream

LOUISA CREEK ROCK CREEK

Surface Area

9

Hydraulic Height

38

Drainage Area

8.2

Nid Storage

175

Hazard Potential

Low

Foundations

Rock, Soil

Nid Height

41
       
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.