El Llano Tank Dam Reservoir Report

Last Updated: December 5, 2025

El Llano Tank Dam, located in McMullen County, Texas, is a private-owned structure built in 1952 with a primary purpose categorized as "Other." This earth dam, with a height of 17 feet and a length of 1520 feet, serves as a water storage facility on the TR-Guadalupe Creek.


°F

°F

mph

Wind

%

Humidity

Summary

Despite not having a spillway, the dam has a storage capacity of 224 acre-feet and a surface area of 35 acres.

The dam has a high-risk assessment level of 2 due to the lack of available hazard potential and condition assessment ratings. It is not regulated by the state and does not have any associated federal agency oversight. Although the dam does not have a designated Emergency Action Plan (EAP) or updated emergency contacts, its functionality and structural integrity are maintained through regular inspections.

Water resource and climate enthusiasts in the area might find El Llano Tank Dam an intriguing site for further study and exploration. Its unique design, historical significance, and impact on the surrounding ecosystem make it a valuable asset in understanding water management practices in the region.

Year Completed

1952

Dam Length

1520

Dam Height

17

River Or Stream

TR-GUADALUPE CREEK

Primary Dam Type

Earth

Surface Area

35

Hydraulic Height

17

Nid Storage

224

Structural Height

17

Outlet Gates

None - 1

Hazard Potential

Not Available

Foundations

Unlisted/Unknown

Nid Height

17
       
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.