Flood Proofing Cities

San Antonio: Solution
Experts consider San Antonio's anti-flood approach among the most innovative solutions to flooding in any metropolitan area. Between 1987 and 1996, federal and local governments funded the construction of a 16,200-foot concrete flood-diversion tunnel beneath the city. It siphons rainfall out of populated areas and carries it to the San Antonio River. Fully 24 feet in diameter, the tunnel was dug with a massive tunnel-boring machine, seen here in action beneath San Antonio.