Mercer No 5 Reservoir Report

Last Updated: January 10, 2026

Mercer No 5 is a privately owned dam located in Lenora, Oklahoma, within Dewey County.


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Summary

Constructed in 1977 by the USDA NRCS, this earth dam stands at a height of 25 feet and has a hydraulic height of 22 feet. With a storage capacity of 110 acre-feet and a maximum discharge of 710 cubic feet per second, Mercer No 5 serves as a vital structure along the TR Canadian River, providing essential water resource management for the surrounding area.

Managed and regulated by the Oklahoma Water Resources Board (OWRB), Mercer No 5 is classified as a low hazard potential dam with a very high risk assessment rating. Despite not being currently rated for its condition, this dam has undergone regular inspections since its last assessment in 2005. Equipped with a controlled spillway and a single valve outlet gate, Mercer No 5 plays a crucial role in flood control and water supply management within the region.

With its primary purpose defined as 'Other' and a focus on resource conservation and management, Mercer No 5 exemplifies the intersection of water infrastructure and environmental stewardship. As climate change continues to impact water resources, dams like Mercer No 5 serve as essential tools for mitigating risks and ensuring sustainable water management practices for future generations.

Year Completed

1977

Dam Length

228

Dam Height

25

River Or Stream

TR CANADIAN R

Primary Dam Type

Earth

Hydraulic Height

22

Nid Storage

110

Structural Height

25

Outlet Gates

Valve - 1

Hazard Potential

Low

Foundations

Soil

Nid Height

25
       
Seasonal Comparison

Weather Forecast

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.