The Hab river, which forms the boundary west of Karachi; the Purali (the ancient Arabus), which drains the low-lying flats of Las Bela; the Hingol (the ancient Tomerus) and the Dasht, which drain Makran, are all considerable streams, draining into the Arabian Sea and forming important arteries in the network of internal communication.
Directly south are the beginnings of the meridional arteries, the Hab, the Purali and the Hingol, which end in the Arabian Sea, leaving a space of mountainous seaboard (Makran) south of the Panjgur and west of the Hingol, which is watered (so far as it is watered at all) by the long lateral Kej river and several smaller mountain streams. Thus southern Baluchistan comprises four hydrographical sections.
From the sea near Karachi the Hab river is the boundary of Sind, and here, across the enclosing desolation of outcropping ridges and intervening sand, a road may be found into Makran.
But from the point where the boundary leaves the Hab to follow the Kirthar range not a break occurs (save one) in 150 m.