The
Traditional Aflaj Irrigation System
INTRODUCTION
Aflaj (sing.
falaj) are the main source of irrigation water in Oman beside wells. They
are utilized in agriculture as well as for domestic use since ancient
times. Similar systems are present in neighboring Arabian countries and
in Persia where it is considered by literature the origin of falaj or
Qanat irrigation system. The Falaj is a system of tapping underground
water which is led by man-made subterranean channels to villages where
it is used for irrigation and domestic purposes .
The water
flow of Aflaj is relatively constant all year round and varies according
to the amount of annual rainfall and drought periods. The main structure
of the falaj consists of: the mother well that may reach a depth of 65
to 200 feet, the main channel, and the access shafts that are built every
50 to 60 m along the channel. The average water flow of the falaj is about
9 gal/sec which is adequate to irrigate a large number of hectares permanently.
Water distribution is fairly complicated but rather efficient to ensure
fair and adequate water supply for all farming lands. The irrigation timing
in the past was based on sun-clock in the day time and the stars in the
night. Water is mainly distributed to the contributors ( owners ) and
their share is inherited, while others may buy a share from the owners
or through rental from regular auctions according to the farmers need
of the water.
According to the Ministry of Water Resources (MWR), the number of aflaj
in Oman is estimated to be 11,000, among which 4,000 are major ones that
are constantly flowing. Maintenance is frequently carried out to maintain
maximum water flow rate of the falaj, since it is the main source of water
for domestic and agricultural purposes.
There are to types of aflaj in Oman; Ghaily falaj , which are dug close
to the ground surface and normally open channels. The water of this kind
of Aflaj comes from Wadi (valley) bottom which accumulates after rainfall
or through higher water table that leak to lower ground levels of Wadis.
This Type, which represent 55% of the total number of aflaj, are around
4 meters deep and two kilometers long. Ghail Aflaj dry out after long
periods of drought with low rainfall since it depends on shallow underground
water table.
The other type of Aflaj is Iddi or Daudi, which is underground canals
and connected to the mother well where the underground water flows and
runs through covered channels to the irrigated lands. There are openings
along this type of falaj used as entrance for maintenance and cleaning
of falaj. The depth of these canals is around 50 m and may reach a length
of 12 kilometers. It consists 45% of the total aflaj and is the main and
permanent source of water in many Omani regions.
The objective of this paper is to present the traditional aflaj systems,
water distribution and management and their physical structure. In addition,
it describes the impact of the falaj system on the organization and community
development of the early settlers of the arid regions in south-east Arabia.
Aflaj
Irrigation System:
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