Marx Reservoir #1 Reservoir Report
Last Updated: December 13, 2025
Marx Reservoir #1 in Oregon is a privately owned earth dam structure primarily used for irrigation purposes, with a capacity to store up to 85 acre-feet of water.
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Summary
Completed in 1964, this reservoir has a structural height of 30 feet and a length of 500 feet, serving the Mud Slough-McMahon Branch water source in Polk County. Managed by the Natural Resources Conservation Service, the dam features a needle outlet gate and an uncontrolled spillway.
Despite being classified as low hazard potential, Marx Reservoir #1 is subject to regular state regulation, inspection, and enforcement to ensure its safety and functionality. With a moderate risk assessment rating of 3, the reservoir's condition remains unrated, indicating a need for ongoing monitoring and maintenance. The last inspection in May 2018 revealed no immediate concerns, but a regular inspection frequency of every 6 years is upheld to address any potential risks or issues that may arise.
Located in proximity to Salem, Oregon, Marx Reservoir #1 stands as a vital resource for local irrigation needs, playing a crucial role in water management and agricultural activities in the region. Enthusiasts of water resources and climate initiatives can appreciate the reservoir's contribution to sustainable water usage and its continued adherence to regulatory standards for safe operation and risk management.
Year Completed |
1964 |
Dam Length |
500 |
Dam Height |
27 |
River Or Stream |
MUD SLOUGH-MCMAHON BRANCH |
Primary Dam Type |
Earth |
Surface Area |
8.48 |
Hydraulic Height |
28 |
Drainage Area |
0.17 |
Nid Storage |
85 |
Structural Height |
30 |
Outlet Gates |
Needle |
Hazard Potential |
Low |
Nid Height |
30 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Willamette River At Salem
|
35800cfs |
South Yamhill River At Mcminnville
|
8310cfs |
Luckiamute River Near Suver
|
3790cfs |
Zollner Creek Near Mt Angel
|
320cfs |
Silver Creek At Silverton
|
52cfs |
Abiqua Creek At Silverton
|
74cfs |
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.
Marx Reservoir #1
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