Publication Name

Climate trends in the Indus river basin

The Indus river basin

Source: Lake Ngangla Rinco, Tibetan plateau, China

Mouth: Arabian Sea

Length: 3,180 km

Area: 1,120,000 km 2 82

Countries: Pakistan (47%), India (39%), China (8%) and Afghanistan (6%) 83

Main tributaries: Kabul, Panjnad

The Indus is the 12th largest river in the world and has its source at Lake Ngangla Rinco on the Tibetan plateau. The river basin contains seven of the world’s highest peaks in addition to Everest, including K2 (8,600 m) and Nanga Parbat (8,100 m). The basin stretches from the Himalayan mountains to the north to the dry, alluvial plains of Sindh province in Pakistan and flows out into the Arabian Sea. The upper Indus river basin lies in a high mountain region resting in the Hindu Kush, Karakoram and Himalayan ranges. The high mountains limit the intrusion of the monsoon. Precipitation patterns in the Hindu Kush and Karakoram ranges are characterized by westerly and south-westerly flows, and most of the precipitation falls in winter and spring from the west. Outside of the polar regions, this basin contains the greatest area of perennial (multi-year) glacial ice in the world (20,000 km 2 ). 84

Pakistan, India and China. River flow is significantly dependent on meltwater from glaciers, which accounts for approximately 41% of total runoff. 85 Glacial melt is crucial for upstream reservoirs to store and release water to downstream areas when most needed. The glaciers serve as natural storage reservoirs, providing year-round supplies to the Indus and some of its tributaries. Adequate discharge of water from the upper Indus basin into the storage lake behind Tarbela Dam is considered crucial. This dam provides water for a substantial proportion of Pakistan’s agricultural production. It also provides 49% of Pakistan’s total hydroelectric power capacity and approximately 13% of total power output. Approximately 80% of the total discharge in the Indus River basin occurs between May and September. The Karakoram range, which lies partly within the Indus basin, has received international attention due to the observation that the glaciers within this range have remained stable or even increased in

mass, whilst other glaciers worldwide and within other Himalayan mountain ranges have receded (the Karakoram anomaly). The ice is thought to be sustained by a unique and localized seasonal pattern that keeps the mountain range relatively cold and dry during the summer. The Indus basin is the 2nd most water stressed basin in the world. 86 At the same time, it ranks among the most important in the world in terms of human dependence, supporting about 215 million people, both directly and indirectly. It is the main source of water for agriculture, energy production, industrial use and human consumption for the people living in the basin. The Indus basin occupies 65% of the territory in Pakistan, which is considered one of the world’s most water stressed countries in the world, with an average rainfall of less than 240 mm per year. About 90% of Pakistan’s agriculture depends on this river. Pakistan has the world’s largest irrigation system, with much of the water from the Indus diverted for irrigation.

Water in the basin is sourced from glacier melt, snow melt and rainfall in the mountains of

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