Prokap & Mcwilliams Reservoir Report

Last Updated: December 18, 2025

Prokap & Mcwilliams is a privately owned dam located in Graham, Oklahoma, on the North Canadian River.


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Summary

Built in 1960 for recreational purposes, this earth dam stands at a height of 40 feet and has a length of 590 feet. With a storage capacity of 60 acre-feet and a spillway width of 1 foot, the dam has a low hazard potential and is classified as very high risk due to its condition assessment not being rated.

Despite being privately owned, Prokap & Mcwilliams is regulated by the Oklahoma Water Resources Board (OWRB) and undergoes regular inspections, with the last one conducted in May 2011. The dam has one outlet gate and is equipped with a valve. In case of emergencies, the dam does not have an Emergency Action Plan (EAP) prepared, and its risk management measures are currently unspecified. While the dam's risk potential is deemed very high, its hazard potential remains low, making it a critical area for water resource and climate enthusiasts to monitor and assess for potential future developments and improvements.

Year Completed

1960

Dam Length

590

Dam Height

40

River Or Stream

NORTH CANADIAN RIV

Primary Dam Type

Earth

Hydraulic Height

40

Nid Storage

60

Structural Height

40

Outlet Gates

Valve - 1

Hazard Potential

Low

Foundations

Soil

Nid Height

40
       
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.