Why do many rivers in the Qaidam Basin flow into salt lakes and saline swamps?

The Qaidam Basin in Qinghai province is characterized as an area of interior drainage, which is the primary reason its rivers flow into salt lakes and saline swamps rather than reaching an ocean.1

Because the basin is geographically enclosed and experiences an extremely arid climate—with annual precipitation totaling less than 4 inches (100 mm)—water that flows into the basin's central lowlands cannot drain outward. Instead, the water evaporates in the high-temperature-variation environment, leaving behind concentrated mineral deposits and creating extensive salt lakes, saline swamps, and features like the Qarhan Salt Marsh.1