Cadillac Desert posits this about most of the American West, it was sparsely populated prior to the widespread usage of pumps for water and dam program (to generate electricity to pump reservoir water) of Bureau of Reclamation and Army Corps of Engineers. Those power plants and population growths might have fueled American productivity in WW2 but it also was a subsidized consolidation of farms under large corporations and rich individuals when it was meant to help smaller farmers. It's an older book with a 2017 update.