North Mountain Flood Detention #3 Reservoir Report

Last Updated: December 5, 2025

North Mountain Flood Detention #3, located in Maricopa County, Arizona, is a key infrastructure designed for flood risk reduction along the Cave Creek-Tr river.


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Summary

Completed in 1975, this earth dam stands at a height of 25.7 feet with a structural height of 32 feet and a length of 1040 feet. With a storage capacity of 136 acre-feet, this dam plays a critical role in mitigating flood hazards in the region.

Managed by the local government and regulated by the Arizona Department of Water Resources, North Mountain Flood Detention #3 has a high hazard potential but is currently assessed to be in satisfactory condition. The dam's spillway, with a width of 100 feet, helps control water discharge during extreme events, with a maximum discharge capacity of 4120 cubic feet per second. Despite its moderate risk level, the dam's risk management measures and emergency preparedness protocols are essential for ensuring public safety and effective flood control in the area.

As a vital component of flood risk reduction infrastructure in Phoenix, North Mountain Flood Detention #3 serves as a crucial safeguard against potential inundation and provides valuable storage and control capabilities during periods of high water flow. With regular inspections and adherence to state regulations, this earth dam continues to play a pivotal role in protecting the community from the impacts of flooding and ensuring the resilience of water resources in the region.

Year Completed

1975

Dam Length

1040

Dam Height

25.7

River Or Stream

CAVE CREEK - TR

Primary Dam Type

Earth

Surface Area

7.4

Hydraulic Height

25.7

Drainage Area

0.54

Nid Storage

136

Structural Height

32

Hazard Potential

High

Foundations

Rock, Soil

Nid Height

32
       
Seasonal Comparison

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Dam Data Reference

Condition Assessment

Satisfactory
No 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

High
Dams 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.