Blanco Tank Dam Reservoir Report

Last Updated: December 5, 2025

Blanco Tank Dam, located in McMullen, Texas, was completed in 1969 for the primary purpose of water supply.


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Summary

This private dam stands at a height of 15 feet and has a length of 875 feet, with a storage capacity of 110 acre-feet. The dam is classified as an earth dam with a buttress core type, serving the surrounding area with a normal storage capacity of 44 acre-feet.

Despite being non-federally regulated, Blanco Tank Dam plays a crucial role in water resource management for the region, particularly for the TR-Guadalupe Creek. With no spillway and a hazard potential that is not available, the dam's risk assessment is considered high. While the condition assessment is not rated, regular state inspections and permitting ensure its operational safety and efficiency for the local community.

For water resource and climate enthusiasts, Blanco Tank Dam serves as a vital infrastructure for water supply in the region. Its construction and design details, along with its location and purpose, contribute to the understanding of how dams play a crucial role in managing water resources and ensuring the sustainability of water supply for communities in Texas. The dam's risk assessment and lack of federal oversight highlight the importance of state-level regulations and inspections in maintaining the safety and functionality of such critical infrastructure.

Year Completed

1969

Dam Length

875

Dam Height

15

River Or Stream

TR-GUADALUPE CREEK

Primary Dam Type

Earth

Surface Area

10

Hydraulic Height

15

Nid Storage

110

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.