hello; I had not heard of this so cannot say anything useful. My first question is where do they get the water to pump back in? The reason ground water is used is because normal natural rainfall is either too sporadic or just not enough inches per season.How helpful is pumping water into the aquifers? I think they began doing that in California.
The only reason to pump water back in I can think of off hand might be to use the aquifers for holding what they can during times of good rainfall or snow pack. That is just a guess.