Granite Reef Diversion Reservoir Report

Last Updated: December 5, 2025

Granite Reef Diversion, located on the Salt River in Arizona, is a federal-owned structure managed by the Bureau of Reclamation.


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Summary

Built in 1907, this concrete dam stands at a height of 29 feet and serves primarily for irrigation purposes, with a storage capacity of 700 acre-feet. The dam has a low hazard potential and a moderate risk assessment, making it a crucial infrastructure for water resource management in the region.

Despite being an older structure, Granite Reef Diversion continues to play a vital role in regulating water flow and providing irrigation water to the surrounding areas. With a maximum discharge capacity of 165,000 cubic feet per second, the dam ensures the efficient distribution of water for agricultural activities. The moderate risk assessment indicates the importance of regular inspections and maintenance to ensure the safety and functionality of the dam for years to come.

Managed by the Bureau of Reclamation, Granite Reef Diversion operates with a low hazard potential and has not been significantly modified since its completion. While the condition assessment is not available, the dam's historical significance and continued operation highlight its essential role in water management and climate resilience efforts in the region. As water resource and climate enthusiasts, understanding the importance of structures like Granite Reef Diversion is crucial for sustainable water management practices and preserving our natural resources.

Year Completed

1907

Dam Length

1128

Dam Height

29

River Or Stream

SALT RIVER

Primary Dam Type

Concrete

Hydraulic Height

23

Drainage Area

13000

Nid Storage

700

Structural Height

29

Hazard Potential

Low

Foundations

Rock

Nid Height

29
       
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.