In a state which is largely arid and experiences hot weather for long periods, it is only natural for the inhabitants to innovate and find solutions to an overall lack of water. With a monsoon-window that stays open for barely three months of the year, the only way to ensure adequate water supply through the year — since historical times — has been via a series of tanks, ponds, artificial lakes and significantly, stepwells.
As observed previously in Dholavira and Lothal, it was channelling water into tanks that helped create and manage medium to large cities in the Harappan age. That enabled the community to have a reservoir of water for bathing, drinking and irrigation. In later, smaller settlements, stepwells — or vavs, as they are popularly called in our state — played pretty much the same role, especially for domestic usage. Today, Rani ki Vav in Gujarat has been recognized as a Unesco World Heritage site.
Read more from source: Early days of vav: Stepwells hold legends as well as lessons for our time – Times of India