(8) The tributary valleys of the Oxus, viz., Maimana, Balkh, Khulm, Kunduz and Kokcha rivers.
The general elevation of the country is considerable. Starting from the Koh-i-Baba it slopes outwards and attains in the table-land of Ghazni and the upper valleys of the Hari Rud, Helmund and Kabul rivers its highest points. Sloping downwards towards its boundaries the waters of its rivers become absorbed by irrigation or lost by evaporation. Except in its north-east corner, it grows more desert-like in character and is bounded in all other directions, if not by a desert, at least by a belt of “bad lands,” in which the work of cultivation and the march of habitation is everywhere arrested by a want of water.
As opposed to the mountain system of Afghanistan there is very little plain. Except between the foot of the northern slopes of the Hindu Kush and the Oxus, at the foot of their south-western slopes along the lower courses of the Hari Rud, the Farah and the Helmund, and the desert to the south of Kandahar, there is none. Certain of the valleys have wide stretches of level, which, although they may not be described as plains, are of such an open, undulating nature that they afford ample space for cultivation. The water question is the great difficulty; although the number of rivers in Afghanistan is considerable only the Helmund is of any magnitude. Generally speaking, they are fordable everywhere during the greater part of the year. Their volume, too, is greatly diminished by the irrigating channels, by which a stream of some promise at its source rapidly dwindles away. The supplies that they yield to cultivation make them of importance.
The following are the chief hydrographic divisions:
(1) The Kabul river and its tributaries.
(2) The Indus affluents.
(3) The basin of the Oxus.
(4) The basin of the Helmund.
(5) The basin of the Hari Rud.