INDUS RIVER

The upper Indus River, between Skardu and the confluence with the Gilgit River, northern great trans-Himalayan river of South Asia and one of the world's longest rivers, with a length of 1,800 miles (2,900 km). The Indus rises in southwestern Tibet at an elevation of about 18,000 feet (5,500 m) and flows in a northwesterly direction along the slopes of the Himalayas, crossing into Jammu and Kashmir from the southeast. The Zaskar, Shyok, Shigar, Gilgit, Astor, and other streams carry snow and glacial meltwaters to the Indus from the main Himalayan range, the Karakoram Range, the Nanga Parbat massif, and the Kohistan highlands. The river crosses the western Kashmir border and then turns south and southwest to enter Pakistan. In Pakistan it emerges from the highlands and flows as a rapid stream between the Swat and Hazara regions and across the Salt Range to enter the semiarid Punjab Plain. The Indus receives its most notable tributaries from the Punjab (Land of Five Rivers) to the east, including the Jhelum, Chenab, Ravi, Beas, and Sutlej rivers. After receiving the waters of the Punjab rivers, the Indus becomes much wider and flows at a slow speed, depositing large quantities of silt along its course. Embankments have been built to prevent flooding, but occasionally these give way and large areas are damaged by overflow. Near Thatta (Tatta) the Indus begins its deltaic stage and breaks into distributaries that reach the Arabian Sea at various points southeast of Karachi. The Indus drains an area of 450,000 square miles (1,165,500 square km), and its annual flow is twice that of the Nile. Because the principal rivers of the Indus drainage network are snow-fed, their flow varies greatly at different times of the year. While the discharge is at a minimum during the winter months, there is a rise of water in spring and summer, and floods occur in the rainy monsoon season from July to September. Their flow is at a maximum where they emerge from the foothills, and little surface water is added in the plains, where much water is lost by evaporation and seepage. The Indus is moderately rich in fish. The best-known and most important edible variety is called the palla. Thatta, Kotri, and Sukkur, all in the Pakistani province of Sindh, are the leading fishing centres. Irrigation from the Indus waters has provided the basis for successful agriculture on the semiarid plains of Pakistan since early times. One of the great modern canal irrigation systems in the world was created by the British administration after 1850. Experience has proved, however, that unless it is carefully controlled, canal irrigation can cause much damage to cultivated land through waterlogging and salinity. Until about 1880 the Indus network carried some navigation, but the advent of the railways and expansion of irrigation works eliminated all but small craft on the lower Indus. The Indus River basin and its drainage network. great trans-Himalayan river of South Asia and one of the longest rivers in the world, having a length of 1,800 miles (2,900 kilometres). It has a total drainage area of about 450,000 square miles (1,165,500 square kilometres), of which 175,000 square miles lie in the Himalayan mountains and foothills and the rest in the semiarid plains of Pakistan. The river's annual flow is about 272 billion cubic yards (207 billion cubic metres)twice that of the Nile and three times that of the Tigris and Euphrates combined. The river's name comes from the Sanskrit word sindhu (river or stream). It is mentioned in the Rigveda, the earliest (c. 1500 BC) chronicles and hymns of the Aryan peoples of ancient India, and is the source of the country's name. Additional reading Descriptions of the Indus are found in surveys of the corresponding regions, such as H.T. Lambrick, Sind: A General Introduction, 2nd ed. (1975); Richard F. Nyrop (ed.), Pakistan: A Country Study, 5th ed. (1984); and Kazi S. Ahmad, A Geography of Pakistan, 3rd ed., rev. by K.U. Kureshy (1972). Works on the Indus itself include Jean Fairley, The Lion River: The Indus (1975), a history of civilization in the Indus valley and of its discovery and exploration; Aloys Arthur Michel, The Indus Rivers: A Study of the Effects of Partition (1967), a discussion of the problem of water resources in the Indus valley; Nazir Ahmad and Ghulam Rasul Chaudhry, Irrigated Agriculture of Pakistan (1988); A.H. Siddiqi, Society and Economy of the Tribal Belt in Pakistan, Geoforum, 18(1):6579 (1987); and Geoffrey Moorhouse, To the Frontier (1984), a descriptive work. Deryck O. Lodrick