City Diversion Reservoir Report
Last Updated: December 18, 2025
City Diversion is a gravity dam located in Idaho Falls, Idaho, along the Snake River.
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Summary
Owned by the local government and regulated by the Idaho Department of Water Resources, this dam serves a primary purpose of hydroelectric power generation and also provides recreational opportunities. Completed in 1982, City Diversion has a height of 30 feet and a length of 1970 feet, with a storage capacity of 1200 acre-feet.
Managed by the Federal Energy Regulatory Commission, City Diversion has a low hazard potential and a moderate risk assessment. The dam features an uncontrolled spillway and one other controlled outlet gate. While its condition assessment is not available, inspections are conducted every three years to ensure its safety and functionality. The dam's emergency action plan was last revised in 2019, and it meets established guidelines for response and risk management.
City Diversion plays a vital role in harnessing water resources for energy production while also offering recreational opportunities for the local community. With its strategic location along the Snake River, this dam exemplifies the intersection of water resource management, climate resilience, and sustainable infrastructure development in the state of Idaho.
Year Completed |
1982 |
Dam Length |
1970 |
Dam Height |
30 |
River Or Stream |
Snake River |
Primary Dam Type |
Gravity |
Surface Area |
50 |
Drainage Area |
9800 |
Nid Storage |
1200 |
Outlet Gates |
Other Controlled - 1 |
Hazard Potential |
Low |
Nid Height |
30 |
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.
City Diversion