For people thinking like robots on this, and not seeing the social impacts, i suggest reading city of quartz. Or if you don't like to read books, watch Chinatown.

Both will show you how the Water & Power's corrupt officials used aqueducts being artificially shut down, and then magically repaired at their convenient timing, to control price of land for their personal riches.

Also, that cost is paid by city, yes, because this initial work is what enable news cities to eventually came into existence, offloading the first city superpopulation problems. It is not done out of altruism, like limited mind people like to boast when defending such short sighted measures.