Mallory Tank Reservoir Report
Nearby: Colter Boynton Lake Dam
Last Updated: December 5, 2025
Mallory Tank, located in Apache County, Arizona, is a vital water resource managed by the Arizona Department of Water Resources.
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Summary
Built in 1918, this earth dam stands at a height of 12.5 feet and serves multiple purposes including fire protection, stock watering, and as a small fish pond. With a storage capacity of 113 acre-feet and a surface area of 27.1 acres, Mallory Tank plays a crucial role in providing water for both agricultural and wildlife needs in the region.
Despite being rated as having low hazard potential, Mallory Tank is identified as having a high risk level due to its age and lack of recent condition assessments. The dam has not been inspected since October 2009, highlighting the need for regular monitoring and maintenance to ensure its structural integrity and safety. While the dam currently does not have spillway infrastructure, it remains under state regulation and oversight to mitigate any potential risks associated with its operation.
As an essential component of the water infrastructure in the area, Mallory Tank serves as a reminder of the importance of proactive management and maintenance of water resources in the face of changing climate conditions. Its role in providing water for firefighting, livestock, and wildlife highlights the interconnectedness of water resources and the need for sustainable practices to ensure their long-term viability in the region.
Year Completed |
1918 |
Dam Length |
296 |
Dam Height |
12.5 |
River Or Stream |
MALLORY DRAW |
Primary Dam Type |
Earth |
Surface Area |
27.1 |
Hydraulic Height |
12.5 |
Nid Storage |
113 |
Hazard Potential |
Low |
Foundations |
Unlisted/Unknown |
Nid Height |
13 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Dam Data Reference
Condition Assessment
SatisfactoryNo 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
HighDams 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.
Mallory Tank