Percy Harry Reservoir Report

Last Updated: December 5, 2025

Percy Harry is a private earth dam located in Dewey, Oklahoma, with a height of 34 feet and a storage capacity of 56 acre-feet.


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Summary

Completed in 1980, this dam serves multiple purposes and is regulated by the Oklahoma Water Resources Board. Situated on TR-ONE HORSE CR, it plays a crucial role in water resource management in the region, with a drainage area of 320 square miles and a surface area of 2 acres.

Despite being rated as "Not Rated" in terms of condition assessment, Percy Harry is classified as having a very high risk potential, highlighting the importance of regular inspections and maintenance. The dam features a controlled spillway and is equipped with a valve outlet gate for water control. Although the hazard potential is currently undetermined, the dam's risk management measures and emergency action plans are essential for ensuring the safety of the surrounding community in the event of a flood or other emergency.

With its strategic location and significant storage capacity, Percy Harry is a key component of the water infrastructure in Dewey, Oklahoma. As a privately-owned structure, it is subject to state regulations and inspections to maintain its integrity and functionality. Climate and water resource enthusiasts can appreciate the vital role this dam plays in managing water resources and mitigating flood risks in the region.

Year Completed

1980

Dam Height

34

River Or Stream

TR-ONE HORSE CR

Primary Dam Type

Earth

Surface Area

2

Hydraulic Height

34

Drainage Area

320

Nid Storage

56

Structural Height

34

Outlet Gates

Valve - 1

Hazard Potential

Undetermined

Foundations

Soil

Nid Height

34
       
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.