The map is a very broad level one. If we narrow down, we will find taht the majority of Satluj is from the rains in Uttarakhand and Ladakh border. Tibet has almost no rain and hence very little water actually comes from Tibet. Yes, it appears to have long distance in Tibet but water proportion is low. Just think about it - how can Tibet river get water when there is very little rain and has limited melting of snowcaps either. Similarly, Ganga and Brahmaputra also has limited water flow from China.
These maps are not giving full picture. In reality, hundreds of small streams join every big river, not just 10-15 as shown in maps. Maps can't have that much detail for convenience
It's not rainwater I'm discussing here.
You know what , I actually went at pains to find this out i.e. how much meltwater from the
Tibetan glaciers contribute to Indian river systems, and it is very substantial. Thank you to the academics (UK) for showing me this.
Here's one such research paper on the Brahmaputra;
https://tc.copernicus.org/preprints/tc-2019-211/tc-2019-211.pdf
the sustainable supply
of GS melt, which is susceptible to climate change, is the key to the local freshwater security, flood prevention and control, and hydroelectric development
The GS melt serves as an essential water supplier for the Brahmaputra river system
results of Lutz et al. (2014), which showed that GS melt
constitutes 33% of the total discharge in the Brahmaputra and that 50% of the annual melt occurs in the summer
Among all model estimates, Lutz’s model reported one of the largest proportions of GS melt
contribution (33%), but still largely underestimated 310 the amount of summer meltwater, according to our estimate from satellite observations
Regarding the Sultaj, actually meltwater forms a significant part of the water flow, as mentioned first by Indian geologists here;
Satluj river is fed
by the glacier melt, snow melt and rain,
https://meetingorganizer.copernicus.org/EGU2018/EGU2018-434.pdf
Some more evidence on the importance of meltwater to the Sultaj and
NOT RAIN.
A new study finds that 55% of the glaciers in the Satluj basin could disappear by 2050 and 97% by 2090 due to climate change.
The
hydrology of the Sutlej is controlled by spring and summer snowmelt in the Himalayas and by the South Asian monsoon.
More than 50% of the annual flow of Satluj river comes from snow and ice melt!!!
https://www.indiawaterportal.org/articles/glacier-melt-threatens-water-reserves-satluj-basin
I'm sorry this is in direct conflict with what you wrote above. You called it
limited when quite clearly it isn't according to established experts in the field. The figure according to Veen, Feddema,Jeelani, and Stearns is as high as 59%.
The contributions of rain and smaller streams etc are small in comparison.
Here's some more with how vital Tibet's glaciers are to the flow of the Sultaj;
The total glacier stored water for 2026 glaciers in Satluj basin was 69 cubic kilometres. About 56% of the total volume (37 cubic kilometres) was stored in large glaciers (with an area of above 5 sq. km) covering an area of 517 sq km. The largest glacier found in the study area was from the Tibetan region (CHINA), which was found to occupy an area of 66.8 sq. km and contained 6.5 gigatonne (Gt) of ice. Most of the glaciers contained less than 0.1 Gt of ice.
https://www.indiawaterportal.org/articles/glacier-melt-threatens-water-reserves-satluj-basin
The team with the above findings;
The study team included Veena Prasad, Anil V. Kulkarni, S. Pradeep, S. Pratibha, Tejal Shirsat, A. R. Arya and Sayli A. Tawde (Indian Institute of Science); Andrew Orr and Daniel Bannister (British Antarctic Survey).
From the respected Divecha Centre for Climate Change at the Indian Institute of Science, Bangalore.
Here's another article which carried the same ground breaking study on loss of glacial water.
https://www.thehindubusinessline.co...-disappear-by-2050-study/article27185928.ece#
By the way my own experiences of this. My own ancestry hails from mountainous regions and as a young lad visiting Pakistan (AJK) I observed how melt water in the summer provided essential flow to our rivers from the Himalayan glaciers.