Chapman Upper Reservoir Report
Nearby: Beer S Reservoir Easterday Reservoir
Last Updated: December 13, 2025
Chapman Upper, located in Malheur, Oregon, is a privately owned irrigation dam completed in 1948 on Granite Creek, a tributary to the Malheur River.
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Summary
This earth dam stands at a height of 15 feet and has a maximum storage capacity of 500 acre-feet, with a normal storage level of 223 acre-feet over its 8.17-acre surface area. The dam serves the primary purpose of irrigation in the region and is regulated by the Oregon Water Resources Department.
With a low hazard potential and a condition assessment that is currently not rated, Chapman Upper is a vital water resource infrastructure in the area. The dam's inspection frequency is every 6 years, with the last inspection conducted in May 2016. In case of emergencies, the dam is equipped with a slide (sluice gate) outlet gate for controlled water release. Although there are no associated structures with the dam, its presence plays a crucial role in supporting agricultural activities and water management in the Riverside region.
As a significant component of the water supply system in Malheur County, Chapman Upper showcases the importance of sustainable water resource management for irrigation purposes. With its historical completion in 1948 and ongoing regulatory oversight by the Oregon Water Resources Department, this dam stands as a testament to the intersection of water resource development, climate resilience, and agricultural sustainability in the region. The infrastructure's role in supporting the local economy and ecosystem highlights the interconnectedness of water resources and climate considerations for a thriving community like Riverside.
Year Completed |
1948 |
Dam Length |
850 |
Dam Height |
15 |
River Or Stream |
GRANITE CREEK, TRIB TO |
Primary Dam Type |
Earth |
Surface Area |
8.17 |
Hydraulic Height |
13 |
Drainage Area |
2.5 |
Nid Storage |
500 |
Structural Height |
15 |
Outlet Gates |
Slide (sluice gate) |
Hazard Potential |
Low |
Nid Height |
15 |
Seasonal Comparison
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Nearby Streamflow Levels
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.
Chapman Upper
Cottonwood Cr - M1