Chesley-wamslee
Chesley-wamslee is an earth dam located in Graham County, Arizona, built in 1975. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Chesley-wamslee
The primary purpose of Chesley-wamslee is flood risk reduction. The dam is designed to control downstream flooding by temporarily storing excess water during storms and releasing it at a controlled rate. The dam is owned by Arizona State Land Department;graham Canal Co. (private). It impounds the Chesley Wash near Pima.
The dam stands 65 feet tall and stretches 1,760 feet across, creates a reservoir covering 73 acres, has a maximum storage capacity of 2,160 acre-feet, and collects water from a drainage area of 8 square miles. Completed in 1975, the structure is well into its service life at over 50 years old.
This dam carries a high hazard potential classification, which means that a failure or uncontrolled release of water would likely cause loss of human life. This classification reflects the consequences of failure, not the likelihood — it indicates that people live or work in the area downstream. Its condition is rated satisfactory, indicating no existing or potential dam safety deficiencies are recognized. An emergency action plan is in place for this dam. The most recent inspection on record was 03/20/2024.
At 65 feet, this dam is taller than 96% of all dams in the United States.
Living Downstream
If you live or work downstream of this dam, consider taking these steps: learn your local evacuation routes, check whether your county emergency management office has a dam failure inundation map, and sign up for local emergency alerts. The Arizona dam safety program can provide more specific information about emergency planning for this structure.
Search for dams near your address to see all dams in your area with hazard classifications and safety data.
Location
| State | Arizona |
| County | Graham |
| Nearest City | Pima |
| River/Stream | Chesley Wash |
| Coordinates | 32.91222, -109.78833 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 65 ft |
| Dam Height | 42 ft |
| Dam Length | 1,760 ft |
| Year Completed | 1975 (51 years old) |
Storage & Hydraulics
| NID Storage | 2,160 acre-ft |
| Max Storage | 2,160 acre-ft |
| Surface Area | 73 acres |
| Drainage Area | 8 sq mi |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | ARIZONA STATE LAND DEPARTMENT;GRAHAM CANAL CO. |
| Owner Type | Private |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 03/20/2024 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | AZ00161 |
| Federal ID | AZ00161 |
| More Info | State Dam Safety Program |