Module 2 (part 2)

Improving Diversion Works

John Ratsey [john.ratsey@ntlworld.com]

Initial layout for Al Mossefiyah Intake

Wadi

flow

Gabion wall

Al Mossefiyah canal

Another canal

Curved gabion wall

Gabion wall to restrict intake opening size

Width ~100m

Suggested layout for Al Mossefiyah Intake Possible bed bar

if acceptable to downstream

users

Gravel embankment to

be constructed by farmers

Gabion wall designed as spillway

Intake structure with orifice

Wadi bank

Obar Fareed (Wadi Tuban)

Armoured head of intake

Spillway

Head regulator

Obar Al Sadain – Wadi Tuban

Bed bar

Armoured head of intake

Spillway

Head regulator

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

Sediment in canal

Gravel in canal reduced, but not avoided

The end of module 2

Thank you