Riley Lake Dam Reservoir Report

Last Updated: December 5, 2025

Located in Bexar, Texas, the Riley Lake Dam is a private structure that serves multiple purposes, including recreation and water supply.


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Summary

Completed in 1970, this earth dam stands at a height of 18 feet and has a storage capacity of 94 acre-feet. It is situated on the TR-CALAVERAS CREEK and is regulated by the Texas Commission on Environmental Quality (TCEQ).

Despite its earth construction and buttress core type, the dam is classified as having a high risk potential due to incomplete data on its condition assessment and hazard potential. With no spillway and limited drainage area, the Riley Lake Dam remains a critical structure for water resource management in the region. While it has not been inspected recently and lacks an emergency action plan, the dam continues to provide essential services for the surrounding area.

As a point of interest for water resource and climate enthusiasts, the Riley Lake Dam offers a glimpse into the complexities of managing water infrastructure in Texas. With its recreational and water supply functions, as well as its proximity to the Galveston District, this dam plays a vital role in the local ecosystem. Despite its risk assessment and lack of recent inspections, the Riley Lake Dam remains a key feature in the region's water management strategy.

Year Completed

1970

Dam Length

957

Dam Height

18

River Or Stream

TR-CALAVERAS CREEK

Primary Dam Type

Earth

Surface Area

9

Hydraulic Height

18

Nid Storage

94

Structural Height

18

Outlet Gates

None - 1

Hazard Potential

Not Available

Foundations

Unlisted/Unknown

Nid Height

18
       
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.