The Indus, one of the great rivers of the world, rises in southwestern Tibet only about 160 kilometers west of the source of the Sutlej River, which joins the Indus in Punjab, and the Brahmaputra, which runs eastward before turning southwest and flowing through Bangladesh. The catchment area of the Indus is estimated at almost 1 million square kilometers, and all of Pakistan's major rivers--the Kabul, Jhelum, Chenab, Ravi, and Sutlej--flow into it. The Indus River basin is a large, fertile alluvial plain formed by silt from the Indus. This area has been inhabited by agricultural civilizations for at least 5,000 years.

The upper Indus Basin includes Punjab; the lower Indus Basin begins at the Panjnad River (the confluence of the eastern tributaries of the Indus) and extends south to the coast. In Punjab (meaning the "land of five waters") are the Indus, Jhelum, Chenab, Ravi, and Sutlej rivers. The Sutlej, however, is mostly on the Indian side of the border. In the southern part of the province of Punjab, the British attempted to harness the irrigation power of the water over 100 years ago when they established what came to be known as the Canal Colonies. The irrigation project, which facilitated the emergence of intensive cultivation despite arid conditions, resulted in important social and political transformations.

Pakistan has two great river dams: the Tarbela Dam on the Indus, near the early Buddhist site at Taxila, and the Mangla Dam on the Jhelum, where Punjab borders Azad Kashmir. The Warsak Dam on the Kabul River near Peshawar is smaller. These dams, along with a series of headworks and barrages built by the British and expanded since independence, are of vital importance to the national economy and played an important role in calming the raging floodwaters of 1992, which devastated large areas in the northern highlands and the Punjab plains.