Mill Creek Storage Dam Reservoir Report
Last Updated: December 23, 2025
Mill Creek Storage Dam, also known as Bennington Lake, was completed in 1942 by the US Army Corps of Engineers in Walla Walla, Washington.
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Summary
This earth dam stands at a structural height of 145 feet and has a hydraulic height of 120 feet, serving primarily for flood risk reduction and recreation purposes. With a storage capacity of 8,300 acre-feet and a drainage area of 80 square miles, the dam plays a crucial role in managing water levels in the Mill Creek offstream.
Despite its high hazard potential, the dam is well-maintained by the US Army Corps of Engineers, with regular inspections and risk management measures in place to address potential flooding risks. The agency works closely with local emergency managers and the public to raise awareness of the dam and ensure preparedness for any dam-related emergencies. Additionally, the dam has an updated emergency action plan and is regularly monitored to maintain its structural integrity and functionality. Overall, Mill Creek Storage Dam serves as an important infrastructure for water resource management in the region, highlighting the critical role of dams in mitigating flood risks and ensuring water security.
Year Completed |
1942 |
Dam Length |
3200 |
River Or Stream |
MILL CREEK OFFSTREAM |
Primary Dam Type |
Earth |
Surface Area |
25 |
Hydraulic Height |
120 |
Drainage Area |
80 |
Nid Storage |
8300 |
Structural Height |
145 |
Hazard Potential |
High |
Nid Height |
145 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Mill Creek At Walla Walla
|
309cfs |
Mill Creek At Five Mile Rd Br Nr Walla Walla
|
634cfs |
Mill Creek Near Walla Walla
|
167cfs |
Walla Walla River Near Touchet
|
1520cfs |
Umatilla River Above Meacham Creek
|
373cfs |
Meacham Creek At Gibbon
|
630cfs |
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.
Mill Creek Storage Dam