A good portion of the Hill Country, including western Hays County, draws its water from the Trinity Aquifer. An
aquifer is a vast underground limestone-encased cavern of stored water. With ever-increasing pumping from this
underground source of water due to economic development and increased water use, the Trinity has been dropping
steadily. Th is aquifer mining, in turn, is sapping area streams and springs. Jacob’s Well (shown in Figure 1) is a spring
that forms the headwaters for Cypress Creek, a source of fl ow for Wimberley’s legendary Blue Hole. Water from
Jacob’s Well fl ows into Cypress Creek, which runs through downtown Wimberley and provides infl ows to the Blanco
River several miles downstream