Summary
Completed in 1955, the dam serves primarily for hydroelectric power generation and recreation purposes. With a structural height of 230 feet and a hydraulic height of 205 feet, the dam has a storage capacity of 593,000 acre-feet and a maximum discharge of 1,200,000 cubic feet per second. Despite its solid construction and maintenance by the US Army Corps of Engineers (USACE), the dam poses a high hazard potential due to potential flooding risks in downstream communities like Bridgeport, Brewster, and Pateros.
USACE has implemented various risk management measures to mitigate threats to life safety and property, including enhanced monitoring, regular inspections, and maintenance of the dam structure. The agency closely monitors rainfall and snowpack forecasts to anticipate high river flow events and takes necessary flood operation actions to prevent overtopping and failure of the dam. Moreover, USACE collaborates with local emergency managers to update the Emergency Action Plan annually, conduct emergency exercises, and engage in stakeholder meetings to ensure a coordinated response in times of crisis. Despite the potential risks, Chief Joseph Dam remains a critical infrastructure for water resource management and energy production in the region.
Year Completed |
1955 |
Dam Length |
4300 |
River Or Stream |
COLUMBIA RIVER |
Primary Dam Type |
Gravity |
Surface Area |
8400 |
Hydraulic Height |
205 |
Drainage Area |
75400 |
Nid Storage |
593000 |
Structural Height |
230 |
Outlet Gates |
Tainter (radial) - 0 |
Hazard Potential |
High |
Nid Height |
230 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Methow River Near Pateros
|
1380cfs |
Okanogan River At Malott
|
2240cfs |
Chelan River At Chelan
|
1100cfs |
Omak Creek Near Omak
|
9cfs |
Methow River At Twisp
|
1130cfs |
Twisp River Near Twisp
|
316cfs |
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.
Chief Joseph Dam