Akhdar is wonderful and is in striking contrast to the barrenness of so much of the coast; water issues in perennial springs from many rocky clefts, and is carefully husbanded by the ingenuity of the people; underground channels, known here as faluj, precisely similar to the kanat or karez of Persia and Afghanistan, are also largely used.
He adopts the karez (or, Persian, kandt) system of underground irrigation, as does the Ghilzai, and brings every drop of water that he can find to the surface; but it cannot be said that he is more successful than the Ghilzai.
Irrigation by "karez" is also largely resorted to.
The karez is a system of underground channelling which usually taps a sub-surface water supply at the foot of some of the many rugged and apparently waterless hills which cover the face of the country.
Certain Ghilzai clans are specially famous for their skill in the construction of the karez or underground water-channel.
Nitre abounds in the soil over all the south-west of Afghanistan, and often affects the water of the karez or subterranean canals.
Open canals are usual in the Kabul valley, and in eastern Afghanistan generally; but over all the western parts of the country much use is made of the karez, which is a subterranean aqueduct uniting the waters of several springs, and conducting their combined volume to the surface at a lower level.
Water comes from karez or underground channels and streams from Varak, fed from the Sikhe Lake, an ancient reservoir which preserves the snow waters on the summit of the mountain.