Sunset Reservoir Report

Last Updated: December 25, 2025

Sunset is a vital flood risk reduction structure located in Maricopa, Arizona, specifically in the city of Wickenburg.


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Summary

Built in 1977 by the USDA NRCS, this earth dam stands at a height of 32 feet and has a length of 560 feet, providing essential protection to the surrounding area against potential flooding events from the Sunset Wash. With a maximum discharge capacity of 4100 cubic feet per second and a spillway width of 40 feet, Sunset plays a crucial role in managing water flow and mitigating flood risks in the region.

Managed and regulated by the Arizona Department of Water Resources, Sunset has a high hazard potential but is currently in satisfactory condition, as assessed in April 2018. Despite its age, Sunset continues to serve its primary purpose effectively, storing a maximum of 169 acre-feet of water and covering a surface area of 9 acres. With a moderate risk assessment rating of 3, ongoing inspections and maintenance ensure that this structure remains resilient and ready to respond to any potential emergencies. Sunset stands as a testament to effective water resource management and climate resilience efforts in Arizona.

Year Completed

1977

Dam Length

560

Dam Height

20

River Or Stream

SUNSET WASH

Primary Dam Type

Earth

Surface Area

9

Hydraulic Height

20

Drainage Area

0.6

Nid Storage

169

Structural Height

32

Outlet Gates

Uncontrolled

Hazard Potential

High

Foundations

Rock, Soil

Nid Height

32
       
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.