Lower Lake Mary
Lower Lake Mary is an earth dam located in Coconino County, Arizona, built in 1907. It carries a High hazard potential classification.
About Lower Lake Mary
The primary purpose of Lower Lake Mary is water supply. The dam stores water for municipal, industrial, or agricultural use, helping ensure a reliable supply for the surrounding area. The dam is owned by Usda Fs (federal). It impounds the Walnut Canyon near Walnut Can. Nat. Mon..
The dam stands 33 feet tall and stretches 650 feet across, creates a reservoir covering 910 acres, has a maximum storage capacity of 22,400 acre-feet, and collects water from a drainage area of 27 square miles. Completed in 1907, the structure is over a century 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. An emergency action plan is in place for this dam. The most recent inspection on record was 09/10/2020.
At 33 feet, this dam is taller than 78% of dams nationwide.
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 | Coconino |
| Nearest City | Walnut Can. Nat. Mon. |
| River/Stream | Walnut Canyon |
| Coordinates | 35.11145, -111.58110 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 33 ft |
| Dam Height | 33 ft |
| Dam Length | 650 ft |
| Year Completed | 1907 (119 years old) |
Storage & Hydraulics
| NID Storage | 22,400 acre-ft |
| Max Storage | 22,400 acre-ft |
| Normal Storage | 11,029 acre-ft |
| Surface Area | 910 acres |
| Drainage Area | 27 sq mi |
| Max Discharge | 3,298 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Water Supply |
| Owner | USDA FS |
| Owner Type | Federal |
| Hazard Classification | High |
| Condition Assessment | Not Rated |
| Last Inspection | 09/10/2020 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | AZ00015 |
| Federal ID | AZ00015 |
| More Info | State Dam Safety Program |