Graham Reservoir Report
Nearby: Ritchey Farm Reservoir Scoggins
Last Updated: December 14, 2025
Graham is a private irrigation dam located in Forest Grove, Oregon, on the banks of Dilley Creek.
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Summary
Built in 1961, this Earth-type dam stands at 33.5 feet tall and stretches 550 feet in length. It serves the primary purpose of irrigation, with a storage capacity of 180 acre-feet and a maximum storage of 220 acre-feet. The dam covers a surface area of 15.25 acres and has a drainage area of 0.57 square miles.
Managed by the Natural Resources Conservation Service, Graham has a low hazard potential and has not been rated for its condition assessment. Despite its age, the dam has undergone inspections every 6 years, with the last one conducted in November 2016. State-regulated and permitted, Graham is subject to regular inspections, enforcement, and oversight by the Oregon Water Resources Department. Situated in Washington County, Oregon, this dam plays a crucial role in supporting local agriculture through its irrigation capabilities.
With a hydraulic height of 28 feet and a NID height of 34 feet, Graham is a vital water resource structure in the region. Its presence helps ensure water availability for agricultural activities and contributes to the overall water management efforts in the area. As a privately owned dam, Graham stands as a testament to the collaboration between private landowners and state agencies in sustaining water resources for the benefit of the community.
Year Completed |
1961 |
Dam Length |
550 |
Dam Height |
32 |
River Or Stream |
DILLEY CREEK |
Primary Dam Type |
Earth |
Surface Area |
15.25 |
Hydraulic Height |
28 |
Drainage Area |
0.57 |
Nid Storage |
220 |
Structural Height |
33.5 |
Hazard Potential |
Low |
Nid Height |
34 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Tualatin River Near Dilley
|
1130cfs |
East Fork Dairy Creek Near Meacham Corner
|
21cfs |
Willamette River At Newberg
|
52600cfs |
Fanno Creek At 56th Ave
|
3cfs |
Fanno Creek At Durham
|
36cfs |
South Yamhill River At Mcminnville
|
8310cfs |
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.
Graham
Tualatin River