case: hadramawt improved traditional engineering 6.6

CASE: HADRAMAWT IMPROVED TRADITIONAL ENGINEERING

6.6

Rainfall isohyets

WADI HADRAMAWT

YEMEN

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

MANY LARGE FARMER-BUILT STRUCTURES IN HADRAMAWT

Water MasterIn many systems the traditional structures have been improved through a mix of modern and traditional techniques

Al Powirigat Traditional Dyke

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 dyke at Hadramaut

Traditional diversion dyke – at angle with the flow of the river

TRADITIONAL DYKE: SPILLWAY/ OVERFLOW

AL ROMALYA TRADITIONAL WEIR REINFORCED WITH CONCRETE

SPILLWAY WITHSTEPPED STONES

TRADITIONAL ABUTMENT

BREACH-ABLE EARTHEN BUND TO BREAK IN HIGH FLOODS AND RELEASE FLOOD WATER INTO THE RIVER

FLOOD CHANNEL INTAKE

TRADITIONAL ABUTMENT

LIME MORTAR STRUCTURES

TRADITIONAL INTAKE IN HADRAMUAT

MOZA SIBHAM DYKE REINFORCED WITH TRADITIONAL ABUTTMENTS

MODERN ABUTMENT FOLLOWING TRADITIONAL DESIGN

COMBINED GABION SPILLWAY WITH TRADITIONAL ABUTTMENT

GABION SPILLWAY

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 CHANNELSTO CLOSE SUPPLIES AFTER AREA IS SERVED

FIELD OVERFLOW STRUCTURE

FIELD TO FIELD FLOW STRUCTURES (SPILLWAY)

FIELD OUTLET STRUCTURE

FIELD TO FIELD FLOW STRUCTURE (INLET OR OUTLET

UNDERFLOW STRUCTURE TO CAPTURE VERY SMALL FLOWS

FIELD SYPHON FOR FIELDS HIGH ABUTMENT