The aquifer's recharge zone, where surface water enters the aquifer, follows the Balcones Fault line, from Brackettville (roughly along U.S. Highway 90), through San Antonio, and north to Austin along but a few miles west of Interstate 35.he Aquifer has a recharge zone of 1,250 square miles (3,200 km 2). Most of the water (75%-80%) that is in the Aquifer originated from some of the creeks and rivers flowing in the area. Two creeks that flow into the Aquifer are the Cibolo and Helotes Creeks.