Pensacola Reservoir Report

Last Updated: December 7, 2025

Pensacola, also known as Grand Lake, is a captivating hydroelectric dam located in Mayes County, Oklahoma.


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Summary

Built in 1940, this multi-arch dam stands at an impressive height of 155 feet and spans a length of 6565 feet. With a maximum storage capacity of 2,197,000 acre-feet and a normal storage level of 1,630,000 acre-feet, Pensacola plays a crucial role in flood risk reduction and hydroelectric power generation in the region.

The dam's controlled spillway, with a width of 1,512 feet, ensures effective water management during times of high discharge. The associated structures include 21 Tainter (radial) outlet gates, enhancing the dam's operational efficiency. Despite its high hazard potential and very high risk assessment rating, Pensacola's condition assessment is currently not available, highlighting the need for ongoing monitoring and maintenance efforts to ensure the safety and stability of this vital water resource infrastructure.

Managed by the Federal Energy Regulatory Commission, Pensacola serves as a key landmark in the Tulsa District, contributing to the overall water resource management and climate resilience efforts in the area. As water resource and climate enthusiasts, understanding the importance of dams like Pensacola in supporting sustainable development and environmental conservation is essential for fostering a resilient and secure future for our communities.

Year Completed

1940

Dam Length

6565

Dam Height

155

River Or Stream

Neosho

Primary Dam Type

Multi-Arch

Surface Area

46500

Hydraulic Height

143

Drainage Area

10192

Nid Storage

2197000

Structural Height

151

Outlet Gates

Tainter (radial) - 21

Hazard Potential

High

Foundations

Rock

Nid Height

155
       
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.