South Well Detention Dam Reservoir Report
Nearby: Creosote Detention Dam Reservoir Dike
Last Updated: December 5, 2025
South Well Detention Dam, located in Graham, Arizona, along the San Simon River, was completed in 1981 by the Bureau of Land Management as a gravity-type structure for flood risk reduction.
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Summary
With a structural height of 24 feet and a hydraulic height of 19 feet, the dam has a storage capacity of 334.8 acre-feet, serving a drainage area of 1.73 square miles. Despite being classified as having a low hazard potential, the dam has not been rated for its condition assessment, with its last inspection dating back to July 2015.
Owned, funded, designed, constructed, regulated, inspected, and operated by the Bureau of Land Management, South Well Detention Dam plays a crucial role in managing flood risks in the region. With a primary purpose of flood risk reduction, the dam stands at 1,062 feet in length and covers a surface area of 16.72 acres. Although lacking a spillway type and outlet gates, the dam's maximum discharge capacity is 250 cubic feet per second, ensuring effective water management during peak flow events.
Ensuring the safety and functionality of South Well Detention Dam remains a priority, as its emergency action plan and risk assessment measures are currently not documented. With a focus on mitigating potential risks and enhancing operational efficiency, ongoing inspections and maintenance efforts are essential to safeguarding the surrounding communities and water resources supported by this vital infrastructure.
Year Completed |
1981 |
Dam Length |
1062 |
River Or Stream |
SAN SIMON RIVER |
Primary Dam Type |
Gravity |
Surface Area |
16.72 |
Hydraulic Height |
19 |
Drainage Area |
1.73 |
Nid Storage |
334.8 |
Structural Height |
24 |
Hazard Potential |
Low |
Foundations |
Unlisted/Unknown |
Nid Height |
24 |
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.
South Well Detention Dam