Satluj River in Himachal :
Satluj rises from beyond Indian borders in the Southern slopes of the Kailash mountain near Mansarover lake from Rakas lake, as Longcchen Khabab river ( in Tibet ). It is the largest among the five rivers of Himachal Pradesh. It enters Himachal at Shipki ( altitude = 6,608 metres ) and flows in the South-Westerly direction through Kinnaur, Shimla, Kullu, Solan, Mandi and Bilaspur districts. Its corse in Himachal Pradesh is 320 km. from Rakastal, with famous tributaries viz. the Spiti, the Ropa, the Taiti, the Kashang, the Mulgaon, the Yula, the Wanger, the Throng and the Rupi as right bank tributaries, whereas the Tirung, the Gayathing, the Baspa, the Duling and the Soldang are left bank tributaries. It leaves Himachal Pradesh to enter the plains of Punjab at Bhakhra, where the world's highest gravity dam has been constructed on this river. Its toatl catchment area in Himachal Pradesh is 20,000 sq. km. Its vedic name is Satudri and Sanskrit name Shatadru. The Satluj finally drains into the Indus in Pakistan. The catchment area of about 50,140 km. of Satluj river is located above the permanent snow-line at an altitude of 4,500 metres. The upper tracts of the Satluj valley are under a permanent snow cover. The prominent human settlements that have come on the banks of the Satluj river are Namgia, Kalpa, Rampur, Tattapani, Suni and Bilaspur. Its total length is 1,448 km.
Important Tributaries of river Satluj :
Baspa River :
Baspa is an important tributary of the river Satluj in its upper courses. The Baspa is joined by many smaller channels draining snow melt waters. The Baspa river has cut across the main Himalayan range. Thereafter it empties itself into the river Satluj in district Kinnaur. Baspa originates from the Baspa hills, joins it from the left bank near Karcham ( Kalpa ). Satluj river leaves Kinnaur district in the West near Chauhra and enters Shimla district.
Spiti River :
The Spiti river originates from Kunzum range and Tegpo and Kabzian streams are its tributaries. Water draining the famous Pin valley area are also a part of the Spiti river system. Its position across the main Himalayan range deprives it from the benefit of the South-West monsoons that causes widespread rain in most parts of India from June to September. The river attains peak discharge in late summers due to glacier melting. After flowing through Spiti valley, the Spiti river meets Satluj at Namgia in Kinnaur district traversing a length of about 150 km. from the North-West beyong that it flows in South-West direction in the Pradesh. Huge mountain rise to very high elevations on either sides of the Spiti river and its numerous tributaries. The mountains are barren and largely devoid of a vegetative cover. The main settlements along the Spiti river and its tributaries are Hansi and Dhankar Gompa.
The Nogli Khad :
It joins Satluj just below Rampur Bushahar. It touches Kullu district in Nirmand tehsil opposite to Rampur tehsil of Shimla district. The river Satluj enters Mandi district near Firnu village in the Chawasigarh and passes through the areas of Mahunm, Bagra, Batwara, Derahat and Dehar. Practically, the whole of the ancient Suket state except Jaidevi and Balh circles drains into Satluj. The main tributaries of the Satluj in district Mandi are Siun, Bahlu, Kotlu, Behna, Siman, Bantrehr, Khadel and Bhagmati.
Soan River :
The Soan river rises from the Southern slopes of the Shivalik range also known as Solasinghi range in the tract to the East of the Beas gap across the Southern periphery of the Kangra valley. It joins the boundary of Himachal Pradesh and Punjab. Its gradient is not very steep and the slopes of the Soan catchment vary from gentle to steep. In the summer the discharge dropes drastically, while during monsoon it is in spate.