Why Asia Has Vast Inland Drainage Basins

Asia's extensive endorheic (inland drainage) regions result from a combination of factors:

1. Mountain Barriers: The Himalayas, Karakoram, and Kunlun Mountains block moisture and runoff from reaching the ocean.
2. Arid Climate: Low precipitation limits surface runoff; evaporation dominates.
3. Permafrost: Permanently frozen ground impedes drainage, creating wetlands and closed lakes.
4. Tectonic Activity: Colliding plates form basins that trap water (e.g., Tarim Basin).
5. Human Engineering: Dams and canals (e.g., Three Gorges Dam) create artificial inland reservoirs.

Major inland drainage areas include the Tarim, Junggar, Qaidam Basins, and the Tibetan Plateau.