Many prosperous cities in the world were built around some steady source of water. Either they are close to sea or they were built in river banks or lake shores. This is not coincidental. These places needed steady source of water because water is an essential resource for sustaining life. These places also flourished more than the others, because water brought more trade, industry and more prosperity.
But humans are smart. Probably a little too much for their own good. We polluted these sources of water, sometimes beyond recovery. We changed the course of these rivers, filled up the lakes to get more land. We didn't realize that by doing so, we are destroying the priceless resource that made us thrive in the first place. The steady source of water was sufficient for the human settlements long back. But with the ever growing human population and shrinking water bodies, we practically invited our days of struggle.
No wonder now many of these cities are facing serious water shortage!!