The Sutlej or Satluj River () is the longest of the five rivers that flow through the historic crossroads region of Punjab in northern India and Pakistan. The Sutlej River is also known as Satadru. It is the easternmost tributary of the Indus River. The Bhakra Dam is built around the river Sutlej to provide irrigation and other facilities to the states of Punjab, Rajasthan and Haryana. The waters of the Sutlej are allocated to India under the Indus Waters Treaty between India and Pakistan, and are mostly diverted to irrigation canals in India like the Sirhind Canal, Bhakra Main Line and the Rajasthan canal. The mean annual flow is 14 million acre feet (MAF) upstream of Ropar barrage, downstream of the Bhakra dam. It has several major hydroelectric points, including the 1,325 MW Bhakra Dam, the 1,000 MW Karcham Wangtoo Hydroelectric Plant, and the 1,500 MW Nathpa Jhakri Dam. The drainage basin in India includes the states and union territories of Himachal Pradesh, Punjab, Ladakh and Haryana. Course The source of the Sutlej is west of the catchment area of Lake Rakshastal in Tibet, as springs in an ephemeral stream. Lake Rakshastal used to be part of the Sutlej river basin long ago and separated from the Sutlej due to tectonic activity. The nascent river flows at first west-northwest for about under the Tibetan name Langqên Zangbo (Elephant River or Elephant Spring) to the Shipki La pass, entering India in Himachal Pradesh state. It then has its main knee heading west-southwest for about to meet the Beas River near Harike, Tarn Taran district, Punjab state. Ropar Wetland in Punjab state is located on the Sutlej river basin. Evidence suggests Indus Valley civilisation also flourished here. Ungti Chu and Pare Chu rivers which drain southeastern part of Ladakh are tributaries of Sutlej river. Continuing west-southwest, the Sutlej enters Pakistan about east of Bhedian Kalan, Kasur District, Punjab province, continuing southwest to water the ancient and historical former Bahawalpur princely state. Few centuries ago, Sutlej river was merging with the Ghaggar river to discharge in to the Arabian sea. In approx. 1797 BC, the course of the Sutlej river moved towards north to join the Beas river. About north of Uch Sharif, the Sutlej unites with the Chenab River, forming the Panjnad River, which finally flows into the Indus river about west of the city of Bahawalpur. The area to the