A day-long field excursion across the Balcones Fault Zone, from San Antonio's mission-era acequias to the caverns beneath the Edwards Plateau. Led by Woodruff and Abbott — reprising a 1986 GSA trip — this guide examines fault-controlled incision, stream piracy, artesian springs, karst, and the flood hazards that make the Balcones Escarpment the most flood-prone rainfall corridor in the conterminous United States.