Most Harappan sites were located in semideserts. Since the land was dry, there was a need for water for agriculture. For irrigation, the people made canals. At the Harappan site of Shortugai in Afghanistan, there are remains of the canals. But in Punjab or Sindh, such remains are not seen. The ancient canals might have disappeared by the accumulation of silt over long periods.
Well, water was also used for irrigation. There were also huge clay jars for storing water for agricultural purposes. (E.g. Dholaveera)
