Medina Lk Nr San Antonio Reservoir Report

Last Updated: December 5, 2025

Medina Lake, located near San Antonio, Texas, was created in the early 1900s as a result of the Medina Dam construction on the Medina River.


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Summary

The lake has a surface area of 5,575 acres and a capacity of 254,000 acre-feet. The primary source of water for the lake is the Medina River, with additional inflows from Parker Creek and Black Creek. The lake serves as a source of drinking water and irrigation for surrounding agricultural areas. The lake also provides recreational activities such as fishing, boating, and swimming. The lake's hydrology is affected by the area's frequent droughts and the amount of snowpack in the surrounding regions. During droughts, the lake's water levels can drop significantly, impacting its recreational and agricultural uses.

Reservoir Details

Lake Or Reservoir Water Surface Elevation Above Ngvd 1929, Ft 24hr Change 0.0%
Percent of Normal 97%
Minimum 968.7 ft
2025-05-23
Maximum 1,065.89 ft
2016-06-03
Average 1,020 ft
Dam_Height 165
Hydraulic_Height 165
Drainage_Area 634
Years_Modified 2012 - Structural
Year_Completed 1913
Nid_Storage 327250
Structural_Height 165
River_Or_Stream MEDINA RIVER
Foundations Soil
Surface_Area 5575
Hazard_Potential Not Available
Outlet_Gates Uncontrolled - 1, Vertical Lift - 5
Dam_Length 1550
Primary_Dam_Type Gravity
Nid_Height 165
       
Seasonal Comparison
Precipitation, Total, In Levels
Reservoir Storage, Acre-Ft Levels
Lake Or Reservoir Water Surface Elevation Above Ngvd 1929, Ft Levels

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.