Olmos Dam


Olmos Dam was originally constructed in 1925-1927 as part of the City of San Antonio’s early efforts to effectuate a flood control plan for San Antonio at a cost of $1.5 million.

In 1973-1974 the city hired Hensley-Schmidt, Inc., Consulting Engineers, to investigate the structural integrity, stability and carrying capacity of the dam. The findings indicated th at the reservoir would contain a 200-year frequency flood but had stability and erosion problems if tested under certain storm conditions. Modifications to the structure were therefore recommended.

In 1976, the City of San Antonio secured federal participation from the Economic Development Administration (EDA), and the mayor appointed an Olmos Dam task force to provide citizen and organization input to help define the criteria to incorporate into the project.

On completion of the Task Force recommendations and engineering plans, the San Antonio River Authority, as project participant and construction coordinator, bid and awarded the construction contract to Clearwater Constructors, Inc., in March 1979. The project included strengthening and anchoring the dam, modifying the gate operations, providing an emergency spillway, relocating Olmos Drive, providing a pedestrian walkway, and improving Devine Road for a total cost of approximately $10 million.

A subsequent contract was awarded to Hogan Mechanical, Inc., in January 1989. The contract consisted of replacing the original gate hoist operators with new Limitorque operators and controls and installing monitoring instrumentation and controls for these gate operators at the Nueva Street Control Center at a total cost of $335,000.

The gates of Olmos Dam can now be monitored and/or controlled from the Nueva St. Dam Control Room.

FLOOD CAPACITY: 200 year at crest elevation 728 feet, Mean Sea Level (MSL)
CREST HEIGHT: 54 feet above Olmos Creek bottom.
SPILLWAY LENGTH: 1,152 feet.
FLOOD GATES: Six, with standby generator.
COMPONENT COSTS: Dam Modifications $7.0 million;
  Olmos Drive Relocation and Modifications $1.5 million;
  Engineering and Administration $1.5 million.
FUNDING: San Antonio River Authority (through Bexar County Contract), $3.835 million;
  City of San Antonio, $.875 million;
  Economic Development Administration $5.625 million.
Olmos Dam
Olmos Dam
Olmos Dam
Olmos Dam
1929 Olmos Dam