Researchers in crosswell seismic tomography attempt to image interwell velocity fields by using traveltimes of transmitted waves generated by a downhole source and recorded by downhole receivers. These traveltimes are governed by subsurface velocities along their travel paths, which in turn provide the basis for adjusting an initial-velocity model such that the traveltimes predicted by ray tracing best-match observed traveltimes.

Between 1951 and 1996, groundwater pumpage from the Carrizo-Wilcox aquifer, one of Texas' major aquifer systems, increased in the area between the Colorado and Brazos Rivers from approximately 10,600 to 37,900 acre-ft/yr, primarily as a result of mining needs. Continued (and possibly greatly accelerated) growth in groundwater demand for a variety of uses is expected through the year 2050.