Jacobs Reservoir Dam Reservoir Report
Nearby: Mud Lake Calderwood Reservoir
Last Updated: December 13, 2025
Jacobs Reservoir Dam, located in Lake County, Oregon, was completed in 1938 and serves as a vital resource for the Fish and Wildlife Service.
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Summary
This earth dam, standing at a height of 15 feet with a hydraulic height of 11 feet, creates a pond that supports fish and wildlife while also providing water supply benefits. The dam has a storage capacity of 1,661 acre-feet and a surface area of 126 acres, drawing water from Guano Creek to maintain its reservoir.
Despite its low hazard potential, Jacobs Reservoir Dam's condition assessment in 2018 revealed poor structural integrity. The dam has undergone multiple structural modifications in 1967, 1983, and 2007 to ensure its stability. With an inspection frequency of every 5 years, the dam's risk assessment is classified as moderate (3), highlighting the need for continued monitoring and maintenance to mitigate potential risks. The Fish and Wildlife Service remains the primary owner and operator of the dam, emphasizing its importance in supporting local ecosystems and water supply needs in the region.
Years Modified |
1967 - Structural, 1983 - Structural, 2007 - Structural |
Year Completed |
1938 |
Dam Length |
395 |
Dam Height |
15 |
River Or Stream |
GUANO CREEK |
Primary Dam Type |
Earth |
Surface Area |
126 |
Hydraulic Height |
11 |
Drainage Area |
30.5 |
Nid Storage |
1661 |
Structural Height |
15 |
Outlet Gates |
Other Controlled |
Hazard Potential |
Low |
Nid Height |
15 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Dam Data Reference
Condition Assessment
SatisfactoryNo 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
HighDams 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.
Jacobs Reservoir Dam
Guano Creek