Chesley-Wamslee Reservoir Report

Last Updated: December 5, 2025

Chesley-Wamslee, located in Arizona, is a private dam primarily used for flood risk reduction along Chesley Wash.


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Summary

Built in 1975, this earth dam stands at 41.7 feet in height and spans 1760 feet in length. With a storage capacity of 2160 acre-feet and a surface area of 73 acres, Chesley-Wamslee plays a crucial role in managing water resources in the region.

Managed by the Arizona Department of Water Resources, Chesley-Wamslee is subject to state regulation, permitting, inspection, and enforcement to ensure its structural integrity and safety. Despite being classified as a high hazard potential dam, recent assessments have deemed its condition as satisfactory. The dam's spillway type is uncontrolled, with a width of 500 feet, serving as a critical feature for managing water flow during periods of high discharge.

Overall, Chesley-Wamslee serves as a vital infrastructure for flood risk reduction in Graham County, Arizona. Its strategic location, design, and operational oversight by state authorities highlight the importance of this dam in protecting nearby communities and managing water resources effectively. For water resource and climate enthusiasts, Chesley-Wamslee represents a significant example of the intersection between infrastructure development and environmental stewardship in the face of changing climate conditions.

Year Completed

1975

Dam Length

1760

Dam Height

41.7

River Or Stream

CHESLEY WASH

Primary Dam Type

Earth

Surface Area

73

Drainage Area

8.4

Nid Storage

2160

Structural Height

65.3

Hazard Potential

High

Foundations

Soil

Nid Height

65
       
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.