The hydrology of Texas is amazingly complex. Here's the major aquifers:
There's a map of minor aquifers too. They can't easily show them on the same map because of overlaps.
Better version of this map and others are available for the clicking from TWDB
The only thing we can be sure of about the future is that it will be absolutely fantastic. So if what I say now seems to you to be very reasonable, then I have failed completely. Only if what I tell you appears absolutely unbelievable, have we any chance of visualizing the future as it really will happen.
- Arthur C. Clarke (h/t Brin)