Flood Control > San Antonio Channel Improvements Project (SACIP) > San Pedro Creek Tunnel

San Pedro Creek Tunnel

The San Pedro Creek flood diversion tunnel is approximately 6,000 feet long with a finished inside diameter of 24 feet, 4 inches lined with precast concrete segments. It commences near the Interstate 35-Interstate 10 interchange, between N. Santa Rosa Street on the west and Camaron Street on the east, where an intake approach channel is constructed (See Figure 2 for route). The tunnel inlet shaft is constructed downstream of the approach channel and is 24 feet, 4 inches in diameter dropping approximately 119 feet to the tunnel invert. The tunnel outlet shaft is 35 feet in diameter and contains embedded piping for dewatering facilities. One (1) 18 foot diameter maintenance shaft, two (2) 4 foot diameter ventilation shafts and two (2) 12 inch diameter hydraulic instrumentation shafts are provided at intervals along the tunnel length.

The tunnel alignment between Interstate 35 and Guadalupe Street follows the alignment of San Pedro Creek adjacent to an area of small industrial/commercial buildings.

An 18 foot diameter maintenance shaft is located approximately 220 feet north of West Houston Street at San Pedro Creek. Two (2) 4 foot diameter ventilation shafts are located approximately 100 feet south of Salinas Street at San Pedro Creek and approximately 100 feet north of East Durango Boulevard at San Pedro Creek, respectively.

The tunnel outlet shaft is located north of Guadalupe Street on the west side of San Pedro Creek. Adjacent to the site are S.X. Callahan, Inc., an automotive hardware outlet store and Richter Bakeries, Inc. On the east side of San Pedro Creek is a railroad yard. San Pedro Creek is located in a concrete channel with vertical walls at this location. A portion of the existing channel wall on the west side is removed to accommodate the ramp structure.

The tunnel inlet, outlet and maintenance shafts were constructed by conventional methods. The tunnel was constructed using a tunnel boring machine (TBM). The TBM was lowered through the outlet shaft in sections and assembled underground. The TBM bored the tunnel going upstream and in August 1989, the TBM was removed in sections through the tunnel inlet shaft. Excavated materials were removed through the tunnel outlet structure and transported to a disposal site. The tunnel became operational in June 1991.

A subsequent San Antonio River Authority contract added additional pumping capacity for tunnel recirculation. Construction of this phase was completed in June 1997.

ATTACHMENT NO. 1

PROJECT DESCRIPTION SUMMARY
SAN PEDRO CREEK TUNNEL
San Antonio Channel Improvement Project

TUNNEL STATISTICS