Chapter 12 - The Indus Delta—Catchment, River, Coast, and People

Abstract

The River Indus is one of the oldest documented rivers, formed by the collision of the Indian and Eurasian Plates more than 45million years ago. The river runs 2900km through four countries (Pakistan, India, Afghanistan, and China). It runs the entire length of Pakistan, and the River Indus basin forms 65% of the total country, with smaller rivers joining the course. The riverbanks have altered over geological times, and the delta has shifted westward. Before 1870, the river flowed with 17 branches into the Arabian Sea, which were blocked during the colonial times for the construction of irrigation canals and flood levees. Today there is only one functional channel (Khobar Creek). The freshwater and sediment flows have been reduced with the construction of large dams and man-made structures, and water is consumed to support agriculture production in the catchment area, nevertheless, the water use efficiency is very low. The scarcity of fresh water during the dry season results in the sea moving upstream, reaching several kilometers up the river, thus affecting the position of the estuary and the riverine, deltaic ecosystem.