Allison Lake Dam Reservoir Report

Last Updated: December 5, 2025

Allison Lake Dam, located in Tyler, Texas, was completed in 1965 and stands at a height of 15 feet with a length of 800 feet.


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Summary

This earth dam, primarily used for recreation purposes, has a storage capacity of 120 acre-feet and covers a surface area of 20 acres. Situated on the Sevenmile Branch river, the dam is owned by a private entity and is not regulated by the state. Despite its age, the dam's condition is currently not rated, and its hazard potential is listed as "Not Available."

With a high risk assessment rating of 2, Allison Lake Dam poses potential concerns for water resource and climate enthusiasts. The dam lacks a spillway and has only one outlet gate, raising questions about its ability to handle maximum discharge effectively. The dam's foundation type and structural design are listed as "Unlisted/Unknown" and "Buttress," respectively, indicating potential vulnerabilities that may require further assessment. Given its age and the lack of recent inspection data, there may be a need for increased monitoring and maintenance to ensure the dam's safety and integrity in the face of changing climate conditions.

As a private-owned structure with limited state oversight, Allison Lake Dam highlights the importance of proactive risk management and emergency preparedness in safeguarding water resources and downstream communities. Climate change impacts, such as increased precipitation and extreme weather events, could pose additional challenges for the dam's resilience. Engaging with local stakeholders, enhancing inspection protocols, and implementing risk reduction measures are critical steps to address the potential hazards associated with this dam and ensure the long-term sustainability of water resources in the region.

Year Completed

1965

Dam Length

800

Dam Height

11

River Or Stream

SEVENMILE BRANCH

Primary Dam Type

Earth

Surface Area

20

Hydraulic Height

11

Nid Storage

120

Structural Height

15

Outlet Gates

None - 1

Hazard Potential

Not Available

Foundations

Unlisted/Unknown

Nid Height

15
       
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.