Context: Recently, the Scientists and students from Wadia Institute of Himalayan Geology (WIHG) have revealed about 35 thousand-year history of river erosion in Ladakh Himalayas.

Key Points of the Study

• The study brings out a 35 thousand-year history of river erosion and identified hotspots of erosion and wide valleys that act as buffer zones.
• The study shows how rivers in drier Ladakh Himalaya operated on longer time scales and how they responded to varying climates.
• The scientists have traced where the rivers draining Himalaya and its foreland erode the most and identify the zones that receive these eroded sediments and fill up.
• The Zanskar catchment was explored by WIHG team to understand the landform evolution in transitional climatic zone, using morpho stratigraphy and provenance study of landforms like valley fill terraces, alluvial fans (triangle-shaped deposit of gravel, sand, and even smaller pieces of sediment, such as silt).
• Their research suggested that the wide valley of Padam, with an area of 48 square km, in the upper Zanskar, has stored a vast amount of sediments in these landforms making it a hotspot of sediment buffering in the Zanskar.
• The dominant factors responsible for sediment erosion were deglaciation and Indian Summer Monsoon derived precipitation in the headwaters despite the presence of a geomorphic barrier (the deep, narrow gorge) between the upper and lower catchments of the river, and it remained connected throughout its aggradation history.

Significance

• The study will help to understand river-borne erosion and sedimentation, which are the main drivers that make large riverine plains, terraces and deltas that eventually become the evolving grounds for civilizations.
• The study brought forwards the 35 thousand-year history of river erosion and identified hotspots of erosion and wide valleys that act as buffer zones.
• It showed how rivers in drier Ladakh Himalaya operated on longer time scales and how they responded to varying climates.
• The Ladakh Himalaya forms a high altitude desert between Greater Himalayan ranges and Karakoram Ranges and the Indus and its tributaries are major rivers flowing through the terrain.
• Understanding of water and sediment routing becomes crucial while developing infrastructure and for other development works in the river catchment area.

About Ladakh Himalayas

• The Ladakh Himalaya forms a high altitude desert between Greater Himalayan ranges and Karakoram Ranges where the Indus and its tributaries are major rivers flowing through the terrain.
• The Zanskar River is one of the largest tributaries of the upper Indus catchment, draining orthogonally through highly deformed Zanskar ranges.
• The two prominent tributaries of Zanskar River are the Doda and TsrapLingti Chu, which confluence at Padam village in the upper valley to form the Zanskar River.