Lake Thunderbird Dam Reservoir Report

Last Updated: December 6, 2025

Lake Thunderbird Dam, located in Polk, Texas, is a privately owned structure that serves multiple purposes including recreation and water supply.


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Summary

The dam, designed by Municipal Engineering Co, is an earth-type dam with a buttress core and stands at a height of 18 feet, with a hydraulic height of 18 feet and a structural height of 20 feet. The dam has a storage capacity of 93 acre-feet, with a normal storage level of 55 acre-feet, making it a vital resource for the surrounding area.

Despite being regulated and inspected by the Texas Commission on Environmental Quality (TCEQ), the dam's condition assessment is not rated, and its hazard potential is listed as not available. The risk assessment for Lake Thunderbird Dam is considered high, with a DSAC risk level of 2. The dam does not have a spillway and is equipped with one outlet gate. The last inspection of the dam was conducted in August 1987, and there is no information available on the frequency of inspections or the preparation of an Emergency Action Plan (EAP).

Overall, Lake Thunderbird Dam plays a crucial role in providing recreational opportunities and water supply in the region. However, with its high risk assessment and lack of recent assessment data, there is a need for continued monitoring and maintenance to ensure the safety and functionality of this important water resource infrastructure.

Dam Length

1610

Dam Height

18

River Or Stream

DRY BRANCH

Primary Dam Type

Earth

Hydraulic Height

18

Nid Storage

93

Structural Height

20

Outlet Gates

None - 1

Hazard Potential

Not Available

Foundations

Unlisted/Unknown

Nid Height

20
       
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.