The availability of water is a crucial element in the choice of campsite or permanent dwelling. Well-dig-ging technology and brick-lined shafts were first found in Harappa, an ancient Indus Valley civilization. An archeological dig at Dholavira in Gujarat, India, disclosed a huge reservoir supplying a city dating to 3000 BCE. The complex water management system held 325,000 cubic yards of rainwater to fill Harappan home cisterns for bathing, cooking, and drinking. A series of brick culverts and drainage lines channeled waste water from the city. The success of hydraulic engineers contributed to the vigor of the community, a mercantile center that traded with Mesopotamia, Persia, and southern Arabia.