Explanation:

The drainage system of Punjab comprises five perennial riverine, numerous seasonal streams and hundreds of gullies. The Ghaggar is a truncated seasonal stream at present, but a victim of river capture and river diversion resulting from the tectonic events that occurred in this region in the past. The discharge of the perennial rivers is subject to wide fluctuations ranging from a flush in August to a low current in April. The Satluj and other perennial streams are not dependent on monsoon rainfall alone for their water supply, but have also supply from the melting of the Himalayan snows. This is more valuable as it comes in the spring and early summer – March, April and May.

Among the five rivers of the core region, the Satluj is indeed the major stream. It has its source in one of the westerly Mansarovar lake in Tibet located at 30°20’N and 81°25’E at an elevation of 4633 metres above sea level. Satluj is an antecedent stream. It existed before the emergence of the Himalayan ranges, which it cuts across during its journey to the plains. In terms of length of its course, the Satluj is second only to the Indus river.