Nondrainage Regions

regions with an arid climate which, as a result of this fact, have no drainage of surface waters into either an interior sea or one of the world’s oceans. Only very powerful rivers, fed in more moist regions, intersect nondrainage regions and find an outlet to the sea (transit rivers, such as the Nile). But within the nondrainage regions even these rivers decrease their watercarrying capacity and do not have stable tributaries. Less powerful transit rivers either empty into salt lakes that have no effluent (such as Balkhash and Tengiz) or they terminate and dry up as a result of evaporation and loss of water through infiltration and form dry deltas and alluvial cones in the lower reaches of the river (for example, the Tedzhen, Murgab, and Zeravshan rivers in Middle Asia). The most extensive nondrainage regions are found in Africa and Asia (for instance, the Aral-Caspian region).