Thalweg
Topic: Drainage System of India: Rivers, Basins and Patterns · NCERT: Class 11, Ch 3 "Drainage System"
Meaning
The thalweg is the line that joins the deepest points along a river channel. You can think of it as the path a boat would follow to stay in the deepest water. Class 11 NCERT notes that as towns and farms spread towards the thalweg, river channels get narrower. That increases flood risk and reduces the water that can be used. The thalweg is also used to fix boundaries along rivers, because it marks the main flowing channel.
Example
In the Sir Creek dispute between India and Pakistan, a tidal channel in the Rann of Kachchh between Gujarat and Sindh, India argues that the boundary should follow the thalweg (mid-channel) of the creek.
Don't confuse with
- Watershed: the high line that divides two river basins. The thalweg is the lowest, deepest line inside one river channel.
Related concepts
- Usability of river water
- Ganga-Kaveri link canal
- Interlinking of rivers
- Parbati-Kalisindh-Chambal-ERCP link
- Godavari-Cauvery link
- Inter-State River Water Disputes Act 1956
- Krishna water dispute
- Satluj-Yamuna Link canal