Morrison Dam Reservoir Report
Nearby: Lockett Reservoir Bully Creek
Last Updated: December 13, 2025
Morrison Dam, also known as Morrison Reservoir, is a historic gravity dam located in Malheur, Oregon, built in 1911 by the Bureau of Land Management for water supply purposes.
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Summary
With a height of 38 feet and a length of 425 feet, the dam holds a maximum storage capacity of 115 acre-feet and covers a surface area of 15.5 acres. It is situated on the South Fork of Little Willow Creek, contributing to the irrigation of the surrounding farm and ranch lands.
Despite its low hazard potential, Morrison Dam is in a poor condition according to the latest assessment in 2020, indicating a need for maintenance and repairs to ensure its continued functionality. The dam has not been modified in recent years and lacks certain emergency preparedness measures such as an Emergency Action Plan (EAP) and updated inundation maps. However, with a regular inspection frequency of 5 years, the Bureau of Land Management is actively monitoring the dam's integrity and safety to mitigate any potential risks.
As an integral water resource infrastructure in the region, Morrison Dam serves as a critical component of the local water supply system. With its historical significance and continued operational importance, efforts to maintain and enhance the dam's condition are essential for ensuring sustainable water management and climate resilience in the area.
Year Completed |
1911 |
Dam Length |
425 |
Dam Height |
38 |
River Or Stream |
S. FK. L WILLOW CREEK |
Primary Dam Type |
Gravity |
Surface Area |
15.5 |
Hydraulic Height |
34 |
Drainage Area |
3.3 |
Nid Storage |
115 |
Structural Height |
33 |
Outlet Gates |
None |
Hazard Potential |
Low |
Foundations |
Unlisted/Unknown |
Nid Height |
38 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Malheur River Below Nevada Dam Near Vale Or
|
109cfs |
Snake River At Weiser Id
|
10700cfs |
Payette River Nr Payette Id
|
1970cfs |
Snake River At Nyssa Or
|
7810cfs |
Sand Run Gulch Nr Parma Id
|
36cfs |
Owyhee River Below Owyhee Dam Or
|
30cfs |
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.
Morrison Dam