Stillhouse Hollow Dam Reservoir Report

Last Updated: December 5, 2025

Stillhouse Hollow Dam, located on the Lampasas River in Bell County, Texas, was completed in 1968 by the US Army Corps of Engineers for the primary purpose of flood risk reduction.


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Summary

The dam, an earth structure with stone core, stands at a height of 195 feet and has a maximum storage capacity of 1,013,800 acre-feet. Despite reducing the risk of flooding for downstream communities, the dam is still classified as having a high hazard potential with risks of concentrated leak erosion and overtopping. In the event of a breach, areas such as Belton, Little River-Academy, and Cameron could see flood wave arrival times within 1.5-3 hours, with downstream areas facing high flood depths and potential devastation.

To mitigate risks associated with the dam, regular inspections, monitoring, and maintenance are conducted by USACE Fort Worth District. Surveillance is increased as lake elevation rises, and new measures such as seepage collection weirs and automated data collection systems have been implemented based on past performance and recommendations from risk assessments. Emergency supply materials are stockpiled, and collaboration with local emergency managers includes annual updates to the Emergency Action Plan, evacuation drills, and communication of risks to stakeholders. Despite ongoing risk management efforts, the potential for significant loss of life and economic damages in the event of a breach underscores the importance of continued vigilance and preparedness.

Year Completed

1968

Dam Length

9720

Dam Height

195

River Or Stream

LAMPASAS RIVER

Primary Dam Type

Earth

Surface Area

6430

Hydraulic Height

195

Drainage Area

1319

Nid Storage

1013800

Structural Height

200

Outlet Gates

Uncontrolled - 0

Hazard Potential

High

Foundations

Soil

Nid Height

200
       
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.