Patterson Reservoir Report
Nearby: Boynton Lake Dam Little Ortega Dam
Last Updated: December 5, 2025
Patterson, a privately owned dam in Woodruff, Arizona, serves multiple purposes including fire protection and providing water for stock or small fish ponds.
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Summary
Completed in 1944, this earth dam stands at a height of 16.5 feet and has a storage capacity of 533.8 acre-feet. Located on the Mail Station Draw river, Patterson plays a crucial role in the local water resource management by regulating water flow and storing essential supplies for various needs.
Managed by the Arizona Department of Water Resources, Patterson is subject to state regulations, inspections, and enforcement to ensure its safety and functionality. With a low hazard potential and a moderate risk assessment rating of 3, the dam has not been rated for its condition but is deemed to be in a satisfactory state. While it lacks certain emergency preparedness features like an Emergency Action Plan (EAP) and inundation maps, the dam's risk management measures are currently unspecified.
Despite its age, Patterson continues to be a vital asset for water resource management in Apache County, Arizona. With a focus on safety and compliance, state regulators oversee the dam's operations and maintenance to ensure its continued functionality and resilience in the face of potential risks and emergencies. For water resource and climate enthusiasts, Patterson serves as a fascinating example of how infrastructure can adapt and evolve to meet the changing needs of a growing community while maintaining a commitment to sustainability and safety.
Year Completed |
1944 |
Dam Length |
2170 |
Dam Height |
16.5 |
River Or Stream |
MAIL STATION DRAW |
Primary Dam Type |
Earth |
Surface Area |
97.05 |
Hydraulic Height |
16.5 |
Nid Storage |
533.8 |
Hazard Potential |
Low |
Foundations |
Unlisted/Unknown |
Nid Height |
17 |
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.
Area Campgrounds
| Location | Reservations | Toilets |
|---|---|---|
Brown Creek Campground
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Los Burros Campground
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Los Burros
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Shush Be Tou
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Shush Bezahze
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Patterson