Deer Flat Lower Reservoir Report
Last Updated: January 11, 2026
Deer Flat Lower, also known as Lake Lowell Lower Dam, is a Federal-owned structure located in Canyon, Idaho.
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Summary
Completed in 1907, this dam plays a crucial role in water resource management and climate resilience in the area. With a dam height of 50 feet and a storage capacity of 173,200 acre-feet, it helps regulate water flow from the Boise River and Snake River, covering a surface area of 9,800 acres and serving a drainage area of 75 square miles.
The dam is primarily made of earth and stone materials, with a rock and soil foundation. It features an outlet gate system for water release, and although it has no spillway, its hazard potential is considered high due to its age and condition. The dam is inspected every two years, with the latest assessment in 2019 rating its condition as fair. Despite the risks associated with its high hazard potential, Deer Flat Lower plays a vital role in water storage and management for the region, highlighting the importance of ongoing maintenance and monitoring to ensure its continued safety and functionality.
Managed by the Walla Walla District of the US Army Corps of Engineers, Deer Flat Lower serves as a key infrastructure for flood control, irrigation, and water supply in the region. Its location in Wilder, Idaho, and proximity to the Boise and Snake Rivers make it a critical component of the local ecosystem and economy. As water resource and climate enthusiasts, understanding the significance of structures like Deer Flat Lower is essential for advocating for sustainable water management practices and climate resilience strategies in the face of changing environmental conditions.
Year Completed |
1907 |
Dam Length |
7200 |
Dam Height |
50 |
River Or Stream |
BOISE RIVER SNAKE RIVER |
Surface Area |
9800 |
Hydraulic Height |
42 |
Drainage Area |
75 |
Nid Storage |
173200 |
Outlet Gates |
Slide (sluice gate) |
Hazard Potential |
High |
Foundations |
Rock, Soil |
Nid Height |
50 |
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 Lower
Jump Creek