Aspects of this topic are discussed in the following places at Britannica.
...permanent streams of Andean origin (the Colorado, Negro, Chubut, Senguerr, Chico, and Santa Cruz rivers). Most of the valleys either have intermittent streams—such as the Shehuen, Coig, and Gallegos rivers, which have their sources east of the Andes—or contain streams like the Deseado River, which completely dry up along all or part of their courses and are so altered by the...
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