importance of water:

Earlier people used to live wherever there was a forest and there was availability of water so that they could get water because in earlier times there was no practice of motors and pumps etc. to draw water from the bottom if the water was sweet in a place. It was very difficult to build a well there, so people liked to live near the water, where there were forests and rivers, then the cities settled in such places, so the big cities of the world are still inhabited by the rivers.