Prehistoric India to 1000 B.C. c11.13

c11.13

In Sind, even if the rainfall was heavier in prehistoric times, cultivation must have depended to a large extent on irrigation works connected with the Indus. At the present day there is an annual increase in the flow of the river in spring, owing to the melting of the winter snows in the Himalayas, where the river rises. This would have caused an annual inundation in primitive conditions, comparable to but less equable and dependable than that of the Nile and more comparable with the Tigris-Euphrates floods. And under these primitive conditions it is important to remember that there are only two really fixed points in the course of the river in Sind - at Sukkur and at Kotri, where it cuts through hard limestone instead of soft soils. Between these points, where the channel cannot vary its position, the Indus would, under natural conditions, without man-made embankments, tend to alter its course yearly, after every successive inundation. There is indeed abundant evidence from the sites of the Harappā Culture that such alteration of course, with consequent disastrous floods, was not uncommon in ancient times.