Deer Flat Middle Reservoir Report
Nearby: Deer Flat Middle Dike Deer Flat Lower
Last Updated: December 15, 2025
Deer Flat Middle, also known as Lake Lowell Orchard Road Dam, is a federal-owned structure located in Canyon, Idaho.
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Summary
This earth dam, primarily designed for purposes other than flood control or irrigation, stands at a height of 14 feet and spans a length of 750 feet. Completed in 1911, it is situated near the Boise River and Snake River, with a drainage area of 75 square miles and a storage capacity of 63,000 acre-feet.
The dam's hazard potential is classified as high, with a fair condition assessment as of September 2019. While there is currently no spillway in place, the structure has been inspected regularly, with the last assessment conducted in September 2019. Despite its age, Deer Flat Middle remains a critical component of water resource management in the region, providing essential storage for agricultural and environmental needs.
As a key feature in the Walla Walla District, Deer Flat Middle plays a crucial role in water management and flood protection efforts in Idaho. With its location in a high-risk area and a significant storage capacity, continuous monitoring and maintenance are essential to ensure the safety and effectiveness of this vital infrastructure. For water resource and climate enthusiasts, Deer Flat Middle serves as a noteworthy example of the ongoing challenges and importance of dam infrastructure in the face of changing environmental conditions.
Year Completed |
1911 |
Dam Length |
750 |
Dam Height |
14 |
River Or Stream |
BOISE RIVER SNAKE RIVER |
Surface Area |
9800 |
Hydraulic Height |
11.5 |
Drainage Area |
75 |
Nid Storage |
63000 |
Structural Height |
16 |
Outlet Gates |
None |
Hazard Potential |
High |
Foundations |
Rock, Soil |
Nid Height |
16 |
Seasonal Comparison
Weather Forecast
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.
Deer Flat Middle