Improving Diversion Works Module 2 (part 2) Improving Diversion Works John Ratsey [john.ratsey@ntlworld.com]

Initial layout for Al Mossefiyah Intake Another canal Curved gabion wall Width ~100m Gabion wall Wadi flow Gabion wall to restrict intake opening size Al Mossefiyah canal

Suggested layout for Al Mossefiyah Intake Possible bed bar if acceptable to downstream users Gabion wall designed as spillway Intake structure with orifice Gravel embankment to be constructed by farmers Wadi bank

Obar Fareed (Wadi Tuban) Spillway Head regulator Armoured head of intake

Obar Al Sadain – Wadi Tuban Head regulator Spillway Bed bar Armoured head of intake

Economics Building flood resistant structures can be expensive The benefits, from reduced maintenance work and improved crops, may be moderate Functional requirements may be changed after 25 or 50 years (higher command levels, even fewer floods)

Improvements to modern intakes Works to improve sediment removal Eg. skimming weir in front of intake Removal of divide wall Works to improve hydraulic performance and flow division Weir crest raising to restore command Works to help flow management

Waqar weir The trash floating down the wadi cannot turn over the weir and goes straight to the intake. Difficult to fix, but note for future designs

Skimming weir Skimming weir constructed in front of head regulator. However, water is needed for flushing

Gravel in canal reduced, but not avoided Sediment in canal Gravel in canal reduced, but not avoided

The end of module 2 Thank you