Are you talking about the Ogallala Aquifer? Do note that the farmers have pretty much switched out to a new kind of pivot that is much more efficient than the ones that were probably mentioned on the history channel, but even before it was better than gravity irrigation.
Your corporate farms have to have something to water their thousands of acres and this is currently the best solution (that I know of), unless you want to move to dry land crops (and if you think grain prices were high before...!)