William L. Jess Dam Reservoir Report

Last Updated: December 13, 2025

William L.


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Summary

Jess Dam, also known as Lost Creek Lake, is a rockfill dam located on the Rogue River in Oregon. Completed in 1976 by the US Army Corps of Engineers, the dam stands at 345 feet tall and has a storage capacity of 465,000 acre-feet. Its primary purpose is flood risk reduction, but it also serves for hydroelectric power generation, irrigation, and recreation. The dam's risk assessment categorizes it as having a moderate hazard potential, with the main risk being an extreme earthquake causing damage that could lead to significant flooding downstream.

Despite the potential risks, USACE is confident in the dam's construction and maintenance, emphasizing its role in mitigating flood risks for the region. The agency continues to evaluate the dam's seismic performance and has implemented measures to reduce risk, including routine inspections, instrumentation monitoring, and emergency action plans. USACE also conducts dam safety exercises with local authorities and first responders to ensure preparedness in case of emergencies. Additionally, the agency is committed to raising community awareness about flood risks and the importance of the dam in protecting downstream areas.

Year Completed

1976

Dam Length

3600

Dam Height

342

River Or Stream

ROGUE RIVER

Primary Dam Type

Rockfill

Surface Area

3430

Hydraulic Height

332

Drainage Area

674

Nid Storage

500000

Structural Height

345

Hazard Potential

High

Nid Height

345
       
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.