Jacobs Reservoir Report

Last Updated: December 5, 2025

Jacobs is a privately owned dam located in Island Park Reservoir, Idaho.


°F

°F

mph

Wind

%

Humidity

Summary

Built in 1935, this earth dam stands at a height of 19 feet and has a hydraulic height of 13.8 feet. It spans 570 feet in length and has a storage capacity of 75 acre-feet. The dam is situated on Blue Lake Sheep Creek and serves a variety of purposes, with a primary purpose categorized as 'Other'.

Despite being labeled as low hazard potential with fair condition assessment, Jacobs poses a very high risk according to the risk assessment, signaling the need for proper risk management measures. The dam has been regulated, permitted, inspected, and enforced by the Idaho Department of Water Resources, ensuring compliance with state regulations. The surrounding area has a drainage area of 12 square miles and a maximum discharge of 333 cubic feet per second, making it vital for water resource and climate enthusiasts to monitor its condition and potential impact on the local ecosystem.

Year Completed

1935

Dam Length

570

Dam Height

19

River Or Stream

BLUE LAKE SHEEP CREEK

Surface Area

20

Hydraulic Height

13.8

Drainage Area

12

Nid Storage

75

Outlet Gates

None

Hazard Potential

Low

Foundations

Rock, Soil

Nid Height

19
       
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.