SPATE IRRIGATION IN YEMEN

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SPATE IRRIGATION IN YEMEN
1.3
???? ??????? ?? ?????
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Spate irrigation globally
???? ??????? - ??????
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Was spate irrigation invented in Yemen??? ????
??????? ????? ?? ????? ?
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Marib Dam?? ????

• Construction started 5000 years ago
• Barrage 18 meter high and 700 meter long
• Irrigation off-takes on both sides (60 cubic
  meter/s)
• Command area of 9600 hectares
• Supported population of 30-50,000 people
• Final catastrophic breach 2400 years ago

• ????? ???? ??? 5000 ???
• ???????? 18 ??? ??? 700 ???
• ????? ???? ?? ???????? 60 ??? ???? / ?????
• ??????? ??????? 9600 ?????
• ???? 30 50000 ????
• ????? ???????? ?? 2400 ???

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SPATE IRRIGATION IN YEMEN ???? ???????????? ?? ?
????

• Yemen is the first country in the world where the
  spate irrigation was in practice. .
• ????? ????? ??? ???? ?? ?????? ?? ?????? ????
  ????????
• This unique system witnessed its zenith during
  the Shebean period in the first millennium BC.
• ??? ??? ?????? ??? ?? ??? ???????? ?? ??????
  ?????? ??? ???????
• The development of trade after the Islamic period
  may have promoted the spread of spate irrigation
  from Yemen to other arid and semi-arid regions.
• ????? ??????? ??? ??????? ??? ??? ?????? ????
  ?????? ?? ????? ??? ??????? ?????? ???? ??????
• Yemen's water resources today have become
  unsustainable due to the neglect of traditional
  spate irrigation system and the over exploitation
  of groundwater for its multiple uses.
• ????? ?????? ?? ????? ??? ?????? ?????? ????
  ?????? ??????? ????????? ???? ?? ?????? ???????
  ???????????? ????????
• In Yemen to spate seasons is exist Sief (March
  to Mid-June) and kharief (July to October)
• ???? ????????? ?? ????? ?? ??? ????? (???? ???
  ??? ?????) ???? ?????? (????? ??? ??????)

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and satellite image for recent Marib dam and old
Marib dam ?? ???? ?????? ?? ??????? ???????? ???
???? ?? ???? ??????
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Yemen satellite image map ????? ????? ????????
????????
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Type of spate systems in Yemen (1) large
coastal systems??? ????? ?????? ?? ?????1-
????? ???? ??????? ?? ????? ???????
Tihama systems ????? ?????
South Yemen Systems ??????? ?? ???? ?????
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Yemen map with main wadis ????? ????? ?????
??????? ????????
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Yemen map with main wadis ????? ????? ?????
??????? ????????
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Yemen map with different climatic Zones ?????
????? ????? ??????? ???????? ????????
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Rainfall isohyets ????? ?????? ??????
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Flash flood in wadis in Yemen ????????? ???????
?? ????? ?????
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Run off in arid and semi arid catchments???????
?????? ?? ???????(???????) ?????? ???? ??????

• Wadis catchments usually little vegetation cover
• ????? ?????? ?? ????? ??????? ???? ???? (????)
• Low infiltration capacity because soil crusting
  and raind rop impact
• ???? ???? ?????? ???? ???? (????) ?????? ??????
  ????? ?????
• This generates local run-off
• ??????? ?????? ?????? ???????
• However it is difficult to correlate rainfall
  with flood events
• ??? ?? ??? ?? ????? ??? ????? ?? ??????? ??????

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No strong relation between rainfall and flood
event?????? ????? ???? ??? ????? ????????
Little rainfall Large run-off ??? ???? ????? ????
????

• Depends on
• Condition of wadi (first rain/second rain).
• Presence of reservoir in catchment.
• Location of the rainfall (close/ far).
• ????? ???
• ??? ?????? ??????? (????? ?????? ???? ?? ???????.
• ???? ???? ???? ?? ??????? ???????.
• ???? ???? ????? (???? ?? ????)

High rainfall Small run-off ??? ???? (????) ?????
???? ????
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Flood hydrograph ????????? ???????

• Flows move down as flood wave initially river
  bed is still dry and reservoirs in catchment are
  empty
• ??????? ??? ?????? ??? ???? ??????? ?? ???????
  ??? ????? ??? ????? ?????? ?? ????? ????
• Typical flood hydrograph??? ????????? ???????
  
• Extremely rapid rise ?????? ????? ?????
• Followed by short recession period ??? ????????
  ???? ?????? ?????

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Example Flood Hydrograph (Wadi Rima) ????
?????????? ??????? (???? ????)
First peak steep rise (in 30 minutes to 4
meter)
Second flood
Recession
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Two rivers Different flood patterns different
proportion under small and large floods?????
????? ????? ?????? ????? ????? ??? ?????????
??????? ????????
Wadi Laba Small catchment Most water as spate
Wadi Rima Larger catchment Subsurface and low
flows
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As a result every wadi has different strategy for
diverting water, that relates to flood patterns,
shape and level of command area and groundwater
conditions?????? ??? ???? ?????????? ?????
?????? ?????? ? ???? ????? ???? ??????? ????
?????? ??????? ??????? ?????? ?????? ???????

• Capture the base flow? ?????? ?????? ???????
  
• Divert the small and medium sized floods only or
  also capturing the peak floods?
• ???? ????????? ??????? ????????? ??? ? ?? ??????
  ????????? ??????? ????
• Improve groundwater recharge?
• ???? ????? ?????? ???????

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Results of land use surveys by NESPAK
(1989) ????? ??? ??????? ?????? ???? ???? ??
???? ?????
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. Crop Cycle for Various Crops in Wadi Bana in
Abyan Region (Spate Irrigated Crops) ???? ?????
???????? ?? ???? ???? ????? ???? (?????? ?????
????? ??????
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Wadi Siham Spate irrigation at Tihama costal
???? ????????? ?? ???? ???? ??? ?????
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Spate irrigation fields at gar-Suadan area at
wadi Dowan - Hadramuat ???? ?????? ?? ??? ?????
????? ???? - ??????
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Traditional diversion structure in Yemen ???????
???????? ????????? ?? ?????
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Gabion spillway and traditional intake at
gar-Sudan area (at wadi Dowan) Hadramuat ???? ??
???????? ????? ?????? ?? ??? ????? ???? - ??????
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Traditional dyke at Hadramaut ??????? ???????? ??
???? ??????
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canals ???????
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Type of spate irrigation systems in Yemen(1)
large coastal systems modernization??? ?????
???? ??????? ?? ?????1- ????? ???? ??????? ??
????? ??????? - ?????
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Type of spate irrigation in Yemen(2) smaller
systems Hadramawt??? ????? ???? ??????? ??
?????( 2) ??????? ??????? - ??????
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Type of spate irrigation in Yemen(3) mini
systems mountain systems??? ????? ???? ?????
???????? ?????( 3 ) ??????? ??????- ?????????
??????? (????? ???????)
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