Technical Note: The Chandrabhaga (Chenab) River catchment in Himachal Pradesh covers 7,789 sq km, calculated from SRTM 30 m DEM in QGIS 3.40 and validated with Survey of India and GSI data.
Origin of Chandrabhaga river.
Chandrabhaga also known as Chenab is formed by confluence of two stream Chandra and Bhaga,which originate near Baralacha Pass from Chandratal and Suraj Tal respectively. Like other mid Himalayan rivers Chandrabhaga is also a consequent river. It is a high altitude river which mainly fed by perennial glaciers of Greater Himalaya and Pir Panjal ranges.
Catchment area of Chenab river in Himachal Pradesh
Total catchment area of river in himachal pradesh is 7789 Sq Km,~( the area is calculated with SRTM 30 Mts, CRS 32643, in QGIS 3.40 and vetor data provided by Geological Survey of India). Chandrabhaga river flows through only two districts of Himachal Pradesh i.e 80 % of its catchment area in Himachal Pradesh is in Lahaul Spiti and rest in Chamba. Further it Drained the 45 % area of Lahaul Spiti and 23 % area of Chamba.
Thus although 80 % catchment area of river in Himachal Pradesh fall in Lahaul Spiti , still it is not main river of District Lahaul Spiti.
Gradient of Chandrabhaga in its upper course, in Lahaul Valley
Descent of Bhaga from Suraj Tal to Darcha is very steep it is roughly 31.50 Mt/km. It come out from mountain like raging torrent ,flowing through gorges and narrow valley. Thereafter upto Tandi river flow swiftly. Milang and Baelung are few important tributaries of river.
Descent of Chandra is 12.30 mt/km. It rise from Chandratal near Kunzum La. Unlike River Bhaga, chandra river flow swiftly. Dara,Chattru, Koksar, Gondola and Sissu are few important settlement of the river. Chandrabhaga flow throug in between Greater Himalaya and Pirpanjal mountain range.
Chandrabhaga and Regional Geology and Glacier
Chandrabhaga roughly flow through South Tibetan Detachment Fault. Unlike Beas and Satluj Chandrabhaga does not fomed wide valley in its course in himachal, this is mainly due to regional geology.
Chandrabhaga basin is full of Perennial glacier. River Chandra is fed by Mukkila glacier, Bara shigri glacier, Chhota Shigri glacier,Gora glacier, Sora Umga glacier and Sonapani glacier. Similarly river Bhaga is fed by Gangstang glacier, Baralacha glacier,Lady of Keylong and Geypang glacier. In recent years change in climate change has increased the intensity of GOLF events.
Map of Chandrabhaga River, in Himachal Pradesh.
Chandrabhaga entry in Pangi Valley of Chamba.
Chandra and Bhaga mingled at Tandi in Pattan valley. From Tandi onward joint stream is known as Chandrabhaga, most population of district is located in this part of district. Chandrabhaga leave the Lahaul and enter the Chamba in Bhujind and leave Chamba near Sandari Nala. In Chamba it is joined by Sansari Nala, which originate from Greater Himalaya crest.
The drainage of Lahaul and Spiti provides more than a map of rivers and streams—it reveals the region’s topography, geology, climate, and human geography. In a cold desert where rainfall is scarce and snowmelt sustains life, rivers are the most powerful natural agents shaping landforms, guiding settlements, and determining the rhythms of economy and culture.
Major River Systems
The district’s drainage is dominated by three rivers: Chandra, Bhaga, and Spiti. The Chandra and Bhaga rise from the Baralacha Pass and meet at Tandi to form the Chenab, while the Spiti flows southeast to join the Sutlej. All are glacier-fed, swift, and confined within steep valleys, their tributaries cutting dendritic patterns into the mountain slopes.
Chandra River
- Source: South-eastern base of the Baralacha Pass (4,890 m).
- Course: Flows 48 km southwest, then turns northwest and west for 64 km before meeting the Bhaga at Tandi.
- Features:
- Chandra Tal, a glacial lake, lies on its left bank near Kunzum.
- Fed by large glaciers: Bara Shigri (the largest in Lahaul) on the left, and Samundri and Sonapani on the right.
- Gradient: Average fall of 12.5 m/km.
- Tributaries: Gramphoo and Sissu streams on the right bank.
Bhaga River
- Source: Southwestern slopes of Baralacha Pass (4,800 m).
- Course: Runs 65 km in a northwest then southwest direction before joining the Chandra.
- Tributaries: Barsi, Milang, and Billing nullahs.
- Valley character: Barren and rocky up to Darcha; wider and cultivable further downstream.
- Gradient: Steeper than the Chandra, with an average fall of 28 m/km.
Chenab River
- Formation: Confluence of Chandra and Bhaga at Tandi.
- Course: Flows northwest for about 75 km before exiting into Chamba district.
- Tributaries:
- Right bank: Shansha, Thirot, Chokang, and the Miyar Nullah (largest tributary, 32 km long).
- Left bank: Lingar, Rashil, Naida, Ghor, and Galigorh.
- Gradient: Average fall of 6 m/km from an altitude of 2,800 m.
- Hydrology: Entirely glacier-fed, maintaining perennial discharge.
Spiti River
- Source: Eastern slopes of the Kunzum Range, at the confluence of Kunzum La Togpo, Kabzina, and Pinglung streams.
- Course: Runs southeast for about 130 km through Spiti Valley before joining the Sutlej at Khab in Kinnaur.
- Tributaries:
- Right bank: Chiomo, Gyundi, Rahtang, Pin, Sumra.
- Left bank: Thamar, Hanse, Tagling, Shilla, Kaza, Tabo, Parechu.
- Pin River: The most important tributary, about 50 km long, rising from the Srikhand Range.
- Lingti River: Another major tributary, 40 km long, providing pastures and irrigation.
- Valley character: Broad, flat, and barren, bordered by vertical cliffs. Settlements cluster around springs and irrigated terraces using kuhls (traditional channels).
