All cities of Harappan civilization have:
Well developed water supply
Indus Valley civilisation is credited with developing the science of Hydrology. They also made proper drainage and irrigation canals based on river flow and rainfall. It was a new science developed.
Lighthouse was invented by ancient Egyptians to direct their ships. Alexandria was a busy port even then.
Harappan civilization people built “levees” to control floods. It is obvious that Indus river would flood often.
Levees are raised platforms or earthfills.
Stepwell is a type of well in which there are stairs to descend and reach the water. In india, even today they are popular and referred to as “bawdi” .
Stepwells were excavated in harappan civilization cities.