Indus River System: Origin, Tributaries and Key Facts

The Indus River originates from the Tibetan Plateau near Lake Mansarovar (also spelled Manasarovar) at an altitude of about 5,182 metres above sea level. It initially flows in a north-westerly direction through Tibet and then enters the Ladakh region of India (Jammu and Kashmir). The river cuts through the Himalayas by forming deep gorges, including one near Nanga Parbat. After flowing through Ladakh and Gilgit-Baltistan, it enters Pakistan and flows through the Punjab plains and Sindh province before finally draining into the Arabian Sea near Karachi. The total length of the Indus is about 3,180 km, of which only about 1,114 km lies within India.

The Indus River has five major eastern tributaries that together form the drainage basin of Punjab. The word 'Punjab' comes from Persian: Panj (five) + Ab (water) = land of five rivers. The five rivers are: (1) Jhelum — originates from Verinag spring in Kashmir; flows through the Kashmir Valley and joins the Chenab; (2) Chenab — the largest tributary of the Indus; originates from the Himalayas in Himachal Pradesh; (3) Ravi — originates near the Rohtang Pass in Himachal Pradesh; flows through Chamba valley; (4) Beas — originates near the Rohtang Pass; flows through Kullu valley (Himachal Pradesh) and enters Punjab; (5) Sutlej — originates from Lake Rakshastal in Tibet, near Lake Mansarovar; enters India through the Shipki La Pass. All five rivers eventually merge and the combined water flows into the Indus in Pakistan.

The Indus River system is one of the most historically significant in the world. The Indus Valley Civilisation (also called the Harappan Civilisation), one of the world's earliest urban civilisations, developed along the banks of the Indus and its tributaries around 3300–1300 BCE. Major Harappan cities like Mohenjo-daro, Harappa, Kalibangan, and Lothal were located in this region. Today, the Indus river system is the lifeline of Pakistan's agriculture, irrigating vast areas in Punjab and Sindh. In India, the Sutlej, Beas, and Ravi rivers are crucial for irrigation in Punjab and Haryana through a network of canals.

The Indus Waters Treaty was signed in 1960 between India and Pakistan, mediated by the World Bank. Under this treaty, the waters of the six rivers of the Indus system were divided between the two countries. The three western rivers — Indus, Jhelum, and Chenab — were allocated to Pakistan, while the three eastern rivers — Ravi, Beas, and Sutlej — were allocated to India. This treaty is one of the world's most successful international water-sharing agreements and has largely survived through decades of conflict between the two nations.

The Indus River basin covers a total area of about 11,65,000 sq km, of which about 3,21,289 sq km lies in India. The river drains parts of Ladakh, Himachal Pradesh, Punjab, and Haryana in India. The Indus plain is one of the most fertile agricultural regions in the world. The river carries a large amount of sediment from the Himalayas, depositing rich alluvial soil in the plains. Major dams on the Indus system in India include the Bhakra Nangal Dam on the Sutlej River (one of India's largest) and the Pong Dam on the Beas River.