W.D. Mayo Lock And Dam Reservoir Report

Last Updated: December 5, 2025

W.D.


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Summary

Mayo Lock and Dam, located in Sequoyah, Oklahoma, along the Arkansas River, was completed in 1970 by the US Army Corps of Engineers for the primary purpose of navigation. This gravity dam stands at a height of 71 feet and has a length of 7400 feet, with a storage capacity of 15,800 acre-feet. The dam is equipped with a controlled spillway and a single lock that is 600 feet long and 110 feet wide, facilitating the passage of vessels through the waterway.

Despite being classified as having a significant hazard potential, the risk assessment conducted in 2015 by the USACE identified potential failure scenarios related to lock structures and gates. To manage and reduce these risks, the USACE has implemented various measures, including the design and construction of a new system for maintenance dewatering and repairs. Additionally, emergency exercises, routine updates to the Emergency Action Plan, detailed inspections, and close coordination with the navigation industry are part of the ongoing risk management efforts. Instrumentation and monitoring systems are also in place to assess changing conditions and ensure the dam's integrity.

In the event of a failure, while downstream flooding is not expected due to the dam's design for navigation purposes, the economic impacts and disruption to navigation traffic would be significant. The proactive risk management approach undertaken by the USACE aims to mitigate these potential consequences and ensure the continued safe operation of W.D. Mayo Lock and Dam for both water resource management and climate resilience.

Year Completed

1970

Dam Length

7400

Dam Height

71

River Or Stream

ARKANSAS RIVER

Primary Dam Type

Gravity

Surface Area

1595

Length Of Locks

600

Hydraulic Height

68

Drainage Area

148084

Nid Storage

15800

Structural Height

71

Hazard Potential

Significant

Foundations

Rock, Soil

Nid Height

71
       
Seasonal Comparison

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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.