no it does not need large amounts of water to survive
Yes.
After searching many websites on the Great Basin, I can confer that such a large area must be natural.
The great salt lake
Nevada
The Great Basin is a large and Beautiful, arid region of the western United StatesThe Great Basin is a large region of the western US. It is most known as the contiguous watershed, between the Wasatch Mountains in Utah and the Sierra Nevada. The Great Basin is a 200,000 square mile intermontane plateau that covers most of Nevada and more than half of Utah, as well as a couple parts of California, Idaho, Oregon & Wyoming. The Great Basin is a series of contiguous watersheds.
nevada
john cena
Nevada
Most of Nevada is covered by the Great Basin Desert butalso has a small portion of the Mojave Desert. The Great Basin also covers a large part of Utah and a small part of California.
The Great Artesian Basin in Australia is estimated to contain 64,900 cubic kilometres (15,600 cu mi) of groundwater.
The Great Basin is a large and Beautiful, arid region of the western United StatesThe Great Basin is a large region of the western US. It is most known as the contiguous watershed, between the Wasatch Mountains in Utah and the Sierra Nevada. The Great Basin is a 200,000 square mile intermontane plateau that covers most of Nevada and more than half of Utah, as well as a couple parts of California, Idaho, Oregon & Wyoming. The Great Basin is a series of contiguous watersheds.
Another name for the Great Basin is the Great Basin Desert. It is a large, arid region in the western United States, characterized by its unique geography and climate, which includes salt flats, mountain ranges, and desert landscapes. The term "Great Basin" often refers specifically to the area defined by its internal drainage, where water does not flow out to the ocean.