The decline of Harappan urbanism probably had many contributing factors. The shift to a concentration on kharif cultivation in the outer regions of t… - Jane McIntosh

[The desertion of the Drishadvati and the Sutlej] is typical of the instability of the river courses in the Indus plains—but in the case of the Saraswati, the effect was not localized but devastating on a major scale. Cities, towns, and villages were abandoned, their inhabitants drifting to other regions of the Indus realms and eastward towards the Ganges, pushing back the centuries-old eastern boundaries of Indus culture and venturing into uncharted territory.

The now-dry Hakra River forms part of this river system. Surveys along its dry bed revealed that this was one of the most densely populated areas of the 3rd millennium, the agricultural heartland of the civilization, although it is now virtually desert.

This work revealed an incredibly dense concentration of sites, along the dried-up course of a river that could be identified as the ‘Saraswati’. . . Suddenly it became apparent that the ‘Indus’ Civilization was a misnomer—although the Indus had played a major role in the rise and development of the civilization, the ‘lost Saraswati’ River, judging by the density of settlement along its banks, had contributed an equal or greater part to its prosperity...Many people today refer to this Early state as the ‘Indus-Saraswati Civilization’ and continuing references [in her book] to the ‘Indus Civilization’ should be seen as an abbreviation in which the ‘Saraswati’ is implied.