The Sutlej has its source near the holiest of lakes - the Mansarovar in Tibet. It is the fastest of the Himalayan Rivers and the only one that takes on the Himalayas head on.

From the source the Sutlej flows northwest parallel to the Himalayan range looking for a gap to penetrate through. After a run of 300-km, it finds one at Shipkila, just short of Leo Pargial mountain. Like maneuvering army, it then makes a full ninety-degree sweep and cuts through the Zanskar range, and offshoot of the Greater Himalayan. As it emerges out of the Zanskar range it is joined by the Spiti River.

Now, reinforced by the Spiti and other small and big glacial streams, the Sutlej makes a diagonal thrust through the Great Himalayan Range, cutting a deep gorge with the sacred Kinner Kailash massif on its left and the Mainrang range to its right. Battle muddied through 60-km of gorge, at Karcham, it is welcomed by the crystal clear blue waters of the Baspa River. The Baspa drains the Sangla valley, considered to be the most beautiful valley in the Himalayas. It is from Karcham for about 25-km that the Sutlej is in its most ferocious and challenging moods-boulders, rocks and rubble are tossed around in mighty foaming rapids, the loose strata of the ranges on the flanks further adding to the debris. It is in this form, 4-km down river from Wangtu, that it meets the "Pick-Up Dam" for the tunnel of the famous Nathpa Jhakri Hydel Project.

After this, the Sutlej makes a 200-km dash till finally it loses its momentum and mingles with the backwaters of the Bhakra Dam. Prior to construction of the Bhakra Dam the Sutlej was most feared for the tremendous damage and misery it caused when in flood. The fast flow with just the right amount of water makes the Sutlej and its tributaries the "Power House of the Himalayas". The Hindustan-Tibet Road running along the banks of the river gives accessibility. The hydel potential of the river is being harnessed by construction of storage dams in its lower sections and through Run of the River projects in its faster sections.

The 'Run of the river" schemes involve erection of a weir/ dams with desalting tanks for storing sufficient water to ensure continuous supply through a tunnel/ open channel to a point above the power house site and then given a drop to operate the turbines. The bigger the drop, more the force and with it power. At places like the 'Baspa stage I" water is again channelised through a tunnel to operate another power station thus avoiding the cost of constructing another weir / dam and desalting chambers.

In the final operating stages of the hydel projects, the protection of existing forests and plantation of new one will be critical. The total hydel power potential in Himachal Pradesh is assessed to be 20,000 mw of which about 50% is from the Sutlej basin. In the absence of green covering in the catchment area, the Sutlej will remain the "Untamed Himalayan power house".