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6.6. CASE: HADRAMAWT IMPROVED TRADITIONAL ENGINEERING. YEMEN. WADI HADRAMAWT. Rainfall isohyets. Hadramawt: special characteristics. Extremely low rainfall (50 mm/year) Very irregular and often heavy floods
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6.6 CASE: HADRAMAWT IMPROVED TRADITIONAL ENGINEERING
YEMEN WADI HADRAMAWT Rainfall isohyets
Hadramawt: special characteristics • Extremely low rainfall (50 mm/year) • Very irregular and often heavy floods • Special efforts to avoid that large floods destroy command area and residential area) much attention for spillways( • Groundwater and hence recharge is important
Al Powirigat Traditional Dyke Water Master In many systems the traditionalstructures have been improvedthrough a mix of modern and traditional techniques
Special structures Diversion structures • Bunds and dykes • Traditional abutments • Spillways • Recharge bunds Command area structures • Water distribution structures • Field to field overflow structures • Low flow field intakes
DIVERSION STRUCTURES • Bunds and dykes • Traditional abutments • Spillways • Recharge bunds
Traditional diversion dyke – at angle with the flow of the river
SPILLWAYWITH STEPPEDSTONES AL ROMALYATRADITIONALWEIRREINFORCEDWITH CONCRETE
FLOOD CHANNEL INTAKE TRADITIONAL ABUTMENT BREACH-ABLE EARTHENBUND TO BREAK IN HIGHFLOODS AND RELEASE FLOOD WATER INTO THERIVER
MOZA SIBHAM DYKE REINFORCED WITH TRADITIONAL ABUTTMENTS
Gabion spillway and traditional intake at gar-Sudan area (at wadi Dowan)Hadramawt
TRADITIONAL LOW RECHARGE WEIR TO SLOW DOWN AND SPREAD FLOODS
COMMAND AREA STRUCTURES • Water distribution structures • Field to field flow structures • Low flow field intakes
WATER DISTRIBUTION: WATER IS DIVIDED PROPORTIONALLY IN SMALL CHANNELS
WATER DISTRIBUTION: GATES USED ON SOME OF THE SMALL CHANNELS TO CLOSE SUPPLIES AFTER AREA IS SERVED
FIELD TO FIELD FLOW STRUCTURE (INLET OR OUTLET
UNDERFLOW STRUCTURE TO CAPTURE VERY SMALL FLOWS