Twin Buttes Reservoir Report

Last Updated: December 5, 2025

Twin Buttes is a federal water resource in San Angelo, Texas, managed by the Bureau of Reclamation and primarily used for flood risk reduction.


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Summary

Completed in 1962, this earth dam stands at a height of 134 feet and has a storage capacity of over 1 million acre-feet. The reservoir covers a surface area of 23,508 acres and serves multiple purposes including irrigation and recreation, making it a vital water source for the region.

Despite its high hazard potential, Twin Buttes has a moderate risk assessment due to its regular inspections and emergency action plans. The dam features an uncontrolled spillway and outlet gates for controlled water release. With a drainage area of 2,472 square miles, the reservoir plays a crucial role in managing water flow from the Mid & So Concho Rivers and Spring Creek. Its strategic location and design make it a key asset for water resource and climate enthusiasts interested in sustainable water management practices in Texas.

Years Modified

1999 - Hydraulic, 1999 - Other, 1999 - Structural

Year Completed

1962

Dam Length

42460

Dam Height

134

River Or Stream

MID & SO CONCHO RIV, SPRING CR

Primary Dam Type

Earth

Surface Area

23508

Hydraulic Height

122

Drainage Area

2472

Nid Storage

1087530

Structural Height

134

Outlet Gates

Other Controlled - 6, Uncontrolled

Hazard Potential

High

Foundations

Rock

Nid Height

134
       
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.