Hesperus Wash (No. 36) Reservoir Report

Last Updated: December 5, 2025

Hesperus Wash (No.


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Summary

36) is a key flood risk reduction infrastructure located in Maricopa, Arizona, specifically in the city of Fountain Hills. Completed in 1973, this earth dam stands at a height of 36 feet and stretches over a length of 1060 feet, serving the primary purpose of flood risk reduction along the Verde River - TR. With a high hazard potential and a satisfactory condition assessment as of January 2018, this structure plays a crucial role in managing water resources and safeguarding the surrounding area from potential inundation.

Managed by the Arizona Department of Water Resources, Hesperus Wash (No. 36) is equipped with an uncontrolled spillway and offers a maximum storage capacity of 482 acre-feet. Its strategic location and design make it an essential component of the local water management system, ensuring the safety and well-being of residents in the event of extreme weather conditions. With regular inspections and enforcement measures in place, this dam remains a reliable asset in mitigating flood risks and maintaining the overall resilience of the region's water infrastructure.

As a focal point for water resource and climate enthusiasts, Hesperus Wash (No. 36) exemplifies the importance of proactive flood risk reduction strategies and effective water management practices. Its critical role in the local ecosystem, coupled with its significant impact on the surrounding community, underscores the need for continued monitoring, maintenance, and investment in sustainable water infrastructure to address the challenges posed by a changing climate and growing population.

Year Completed

1973

Dam Length

1060

Dam Height

36

River Or Stream

VERDE RIVER - TR

Primary Dam Type

Earth

Surface Area

28

Hydraulic Height

36.5

Drainage Area

2.8

Nid Storage

482

Structural Height

49

Hazard Potential

High

Foundations

Soil

Nid Height

49
       
Seasonal Comparison

Weather Forecast

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.