Longhorn Lake Dam Reservoir Report

Last Updated: March 11, 2026

Longhorn Lake Dam, located in Gillespie County, Texas, stands as a testament to engineering excellence and environmental stewardship.


Summary

Completed in 1967, this earth dam on Palo Alto Creek serves primarily for recreational purposes, offering a picturesque spot for water enthusiasts and nature lovers alike. The dam boasts a height of 36.7 feet and a length of 445 feet, with a storage capacity of 260 acre-feet and a maximum discharge of 5400 cubic feet per second.

Despite its age, Longhorn Lake Dam remains a vital structure in the region, providing essential water resource management and flood control. The dam's uncontrolled spillway and two outlet gates ensure efficient water release when needed, maintaining safety and stability for surrounding communities. While not state-regulated, the dam undergoes regular inspections to ensure its integrity and functionality, with a moderate risk assessment rating of 3.

With its serene surroundings and functional design, Longhorn Lake Dam represents a harmonious blend of human ingenuity and natural beauty. As water resource and climate enthusiasts explore this iconic structure, they can appreciate the careful planning and maintenance that have made it a lasting and valuable asset in the Texas landscape.



°F

°F

mph

Wind

%

Humidity


15-Day Weather Outlook


Year Completed

1967

Dam Length

445

Dam Height

36.7

River Or Stream

PALO ALTO CREEK

Primary Dam Type

Earth

Surface Area

13

Hydraulic Height

36.7

Drainage Area

1.8

Nid Storage

260

Structural Height

36.7

Outlet Gates

Uncontrolled - 2

Hazard Potential

Not Available

Foundations

Unlisted/Unknown

Nid Height

37
       
Seasonal Comparison

5-Day Hourly Forecast Detail

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.