Mcnary Lock And Dam - Pasco Levee 12-1 Reservoir Report
Last Updated: December 13, 2025
Mcnary Lock and Dam - Pasco Levee 12-1, also known as the Tri-Cities Levees, is a federal structure located in Pasco, Oregon along the Columbia River.
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Summary
Completed in 1952 by the US Army Corps of Engineers, this Earth-type dam stands at a height of 30 feet and serves the primary purpose of flood risk reduction. With 12 associated structures, including other levees and locks, this dam plays a vital role in managing water levels and protecting the surrounding areas from potential flooding.
Managed and funded by the US Army Corps of Engineers, Mcnary Lock and Dam is subject to regular inspections and risk assessments to ensure its structural integrity and effectiveness in flood risk management. With a high hazard potential, the dam is equipped with emergency action plans, inundation maps, and risk management measures to address any potential threats or emergencies. The Corps works closely with local emergency managers and the community to raise awareness about the dam and to prepare and respond effectively in the event of a dam-related emergency, demonstrating a commitment to safety and proactive risk management.
In the face of unpredictable weather events and varying water levels, the US Army Corps of Engineers remains vigilant in monitoring and maintaining Mcnary Lock and Dam to minimize flood risks and protect the surrounding areas. By prioritizing activities that reduce risks, engaging with stakeholders, and regularly updating emergency plans, the Corps ensures the ongoing safety and functionality of this critical water resource infrastructure.
Year Completed |
1952 |
Dam Height |
30 |
River Or Stream |
Columbia |
Primary Dam Type |
Earth |
Hazard Potential |
High |
Nid Height |
30 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Yakima River At Kiona
|
20700cfs |
Walla Walla River Near Touchet
|
1700cfs |
Umatilla River Near Umatilla
|
1540cfs |
Mill Creek At Walla Walla
|
392cfs |
Yakima River At Mabton
|
26200cfs |
Umatilla R At W Reservation Bndy Nr Pendleton
|
764cfs |
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.
Area Campgrounds
| Location | Reservations | Toilets |
|---|---|---|
Columbia Park
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Hood Park
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Ice Harbor Ramp - Lake Sacajawea
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Mcnary Lock And Dam - Pasco Levee 12-1
Columbia Park Trail 1106, Richland