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

San Antonio River Tunnel

The San Antonio River flood diversion tunnel is approximately 16,200 feet long with precast concrete segmented liners of 24 feet, 4 inches inside diameter. The tunnel starts near Josephine Street where the tunnel inlet shaft is constructed adjacent to the existing channel (See Figure 2 for the tunnel's route). The inlet shaft is 24 feet, 4 inches in diameter dropping approximately 118 feet to the tunnel invert. The tunnel outlet shaft near Lone Star Boulevard is 35 feet in diameter and contains embedded piping for dewatering facilities. Two (2) 18 foot diameter maintenance shafts, three (3) 4 foot diameter ventilation shafts and two (2) 12 inch diameter hydraulic instrumentation shafts are provided at intervals along the tunnel length.

The tunnel intake shaft is located between West Josephine Street and Highway 281 North (See Figure 3 for profile of the San Antonio River Tunnel). Borden's Dairy is on the west side of the river and a small manufacturing plant is located on the east side of the river.

The tunnel generally follows the San Antonio River alignment between Josephine Street and 13th Street. The tunnel alignment between 13th Street and Brooklyn Avenue is west of the river.

A 4 foot diameter ventilation shaft is located near the Camden Street bridge on the north bank of the river. An 18 foot diameter maintenance shaft is located at Brooklyn Avenue and the river.

The tunnel, between Brooklyn Avenue and the junction of North and South Alamo Streets, passes under several 2 to 3 stories high commercial/industrial type structures. The largest structure in this reach is the 15 story Valero Energy Building at Avenue B and 6th Avenue. The tunnel passes under the parking lot of this building.

A 4 foot diameter ventilation shaft is located at the edge of the Broadway Avenue pavement between Third and Fourth Streets.

The tunnel, between North Alamo Street and South St. Mary's Street, follows the alignment of South Alamo Street. Alamo State Park and the Alamo, Hemisfair Plaza, LaVillita, Paseo del Rio, the Convention Center and Beethoven Hall are located along this reach of the tunnel. The larger structures along this reach are the 8 story Gibbs Building, the 20 story Hilton Hotel and the 7 story Four Seasons Hotel.

An 18 foot diameter maintenance shaft is located approximately 400 foot south of Durango Boulevard adjacent to the fire station on Water Street.

The tunnel alignment, from the junction of South Alamo Street and Camargo Street, continues in a southerly direction to South St. Mary's Street then continues along South St. Mary's Street to the Eagleland Street intersection. From Eagleland Street, the tunnel alignment follows a southwesterly direction to the San Antonio River under the Southern Pacific Railroad viaduct.

The tunnel alignment along this reach is under small commercial/industrial/residential buildings of 1 or 2 stories. A 4 foot diameter ventilation shaft is located north of Pereida Street and 20 feet east of South St. Mary's Street.

The tunnel outlet structure is located south of the Southern Pacific Railroad, north of Lone Star Boulevard and west of the river.

Construction for the San Antonio River Tunnel Inlet Structure started in September 1993. The contractor, BRH Garver, constructed a water feature, park facilities, betterments, channelization, and tunnel recirculation for the flood control tunnel. A pumphouse was also constructed, mostly below ground level to operate pumps to recirculate tunnel water to supplement river flow during the summer months. This project is a coordinated effort between the U.S. Army Corps of Engineers and the San Antonio River Authority. The Corps bid the project on behalf of the River Authority. Total construction cost was $16.9 million.

Notice to proceed for the San Antonio River Tunnel Outlet Structure was given to Martin K. Eby Construction Company, Inc. on May 5, 1995 and the project was completed in December 1997 at a total cost of $10.1 million. This project includes a water feature, a galvanized steel trellis over a pedestrian plaza, park facilities, betterments, channelization and a gatehouse for tunnel water recirculation. The project was jointly administered by the U.S. Army Corps of Engineers and the San Antonio River Authority.

PROJECT DESCRIPTION SUMMARY
SAN ANTONIO RIVER TUNNEL
San Antonio Channel Improvement Project

TUNNEL STATISTICS