Big Cliff Dam Reservoir Report

Last Updated: December 23, 2025

Big Cliff Dam, located on the North Santiam River in Oregon, was completed in 1954 and serves as a key hydroelectric facility managed by the US Army Corps of Engineers.


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Summary

Standing at 172 feet tall with a gravity design, the dam provides essential water storage for the region, with a maximum storage capacity of 5,930 acre-feet. Despite being labeled as a high hazard potential structure, a recent risk assessment conducted by USACE in 2012 categorized the dam's risk level as low.

The risk assessment highlighted potential challenges posed by extreme earthquake events that could damage the spillway gates, leading to uncontrolled releases and downstream flooding. However, USACE has implemented various risk management measures, including routine inspections, instrumentation for monitoring dam performance, and an Emergency Action Plan (EAP) to guide response in emergency situations. The agency also collaborates with local authorities and community members to increase awareness of flood risks and ensure preparedness for any potential events.

While the Willamette Valley dams, including Big Cliff Dam, play a crucial role in reducing flood risks in the region, they cannot completely eliminate the possibility of flooding during extreme weather events. USACE continues to prioritize dam safety and invest in infrastructure maintenance to mitigate risks and safeguard downstream communities from potential flooding impacts.

Year Completed

1954

Dam Length

280

Dam Height

131

River Or Stream

NORTH SANTIAM RIVER

Primary Dam Type

Gravity

Surface Area

141

Hydraulic Height

101

Drainage Area

452

Nid Storage

5930

Structural Height

172

Hazard Potential

High

Foundations

Rock

Nid Height

172
       
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.