Jemima K Reservoir Report

Last Updated: December 18, 2025

Jemima K is a privately-owned irrigation dam located in Payette River, Idaho.


°F

°F

mph

Wind

%

Humidity

Summary

Built in 1974, this earth dam stands at 71.2 feet high, with a hydraulic height of 66.3 feet and a length of 2600 feet. With a storage capacity of 2650 acre-feet, it serves the primary purpose of irrigation for the surrounding area, covering a drainage area of 3.5 square miles.

Despite being in fair condition according to a 2017 assessment, Jemima K poses a significant hazard potential due to its uncontrolled spillway type and the risk of moderate flooding. The dam has experienced regular inspections every four years, with the last one conducted in May 2017. This dam is regulated by the Idaho Department of Water Resources and has state permits for operation, inspection, and enforcement.

Located in Valley County, Idaho, Jemima K plays a crucial role in water resource management for the region, ensuring a stable water supply for agricultural activities. Its design, construction, and operation are all in compliance with state regulations, highlighting the importance of proper infrastructure maintenance and risk management in the face of changing climate conditions.

Year Completed

1974

Dam Length

2600

Dam Height

71.2

River Or Stream

WEST FORK BEAVER CREEK BEAVER CREEK

Surface Area

115

Hydraulic Height

66.3

Drainage Area

3.5

Nid Storage

2650

Outlet Gates

Slide (sluice gate)

Hazard Potential

Significant

Foundations

Rock, Soil

Nid Height

71
       
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.