Traditional Aflaj Irrigation System
of aflaj depends on whither they utilize shallow or deep groundwater.
Two types of aflaj are common in Oman, which are called Daudi (Qanat/Iddy)
and Ghaily. A third type which can be found in few places and originate
from groundwater springs, is the Ainy falaj.
Daudi Falaj (qanat):
consists of a long underground tunnel of tens of km long at depth reaching
tens of meters at the source of water (mother well). These aflaj constitute
about 45% of the total number of aflaj existing in Oman. Daudi aflaj are
usually perennial in nature in which flow is available throughout the
system consists of surface channels reaching a depth of 3 to 4 meters
and collect water from wadi channels after periods of continues rainfall.
The discharge of such aflaj increases instantly after rainfall events
and decreases rapidly and dry during drought periods. The lengths of these
aflaj varies between 500 to 2000 meters. The width of aflaj channel depends
on the quantity of water which could be collected from the wadi. Aflaj
of Ghaily type constitute about 55% of the total aflaj in Oman. The ghail
or surface flow is highly localized and somewhat empheral, but in the
lower reaches tens of kilometers along wadis. Typical ghaily falaj is
more common in rainy areas such as Lahj in Yemen. Maktari described this
type as water which runs together from springs and flows into the bed
of wadi as referred by Lahjis. The water of this falaj is divided on time
periods to all farms and normally at no charge. The qanat is open and
whoever use the falaj must clean his own water path, so the channel are
cleaned from the upstream until it reaches the lower parts of the village.
In many of these the water is occasional depending on the rainfall and
cultivated lands. The water is not used for domestic purposes since it
is normally open and may be unsuitable for drinking. One person is in
charge of the falaj for distribution and maintenance of irrigation water.
type of aflaj originates from groundwater springs, such as Falaj Al Kasafah
in Rustaq. Some of the springs are thermal, i.e. having warm water. Length
of falaj channels extend from 200 meters to 100 meters. The number of
such aflaj is very limited to less than 1% of the total aflaj in Oman.