>you have to ask how we ended up with these canal systems, what the tradeoffs are in a landscape setup this way rather than one where water infiltrates the ground and stays hydrated

Good questions I guess but what more specifically are you saying would happen if we delete the canals? What does "the water infiltrates the ground and stays hydrated" mean?

Presumably deleting the canals means water will still be relatively scarce and the distribution will simply by different and not controlled by the state.