Although beset by drought, Iran is set to export water to Kuwait.
Alan Sparks explains the paradox.
Near Defzul, in western Iran, the recently constructed Karkheh Dam holds back 5,600M. m 3of water. But while the country is blighted by prolonged drought, the water will be carried 540km south to Kuwait.
The paradox is explained by Gulf Utilities director Brian Hendry: 'The topography of the terrain between the drought affected areas and the Karkheh Dam currently make a pipeline unfeasible. Water provision will be better met by financing other schemes through the royalties earned from exporting water by an easier route.'
So 50M litres of water/day will head south along a ú2.4bn, steel pipeline - equating to 10.5m 3per second. The route takes it 330km overland, before a subsea section crosses the Gulf to deliver the supply to a water transfer terminal in Kuwait.
However Hendry stresses that 'although this is a big scheme it will be merely complementary to desalination. There's no question that Kuwait will ever be dependent on Iran and this pipeline for its water.'
In fact only 0.6% of the Karkheh's flow will be taken to Kuwait. The Dam was principally built to provide 400MW of electricity and regularise water flow to the irrigated farmland downstream. Such large scale projects are not unusual in Iran, explains Gulf Utilities director Colin Clark.
For the overland section the 2.74m diameter, 25mm thick steel pipe follows the route of the main road. A service road will run along the length, providing easy access for maintenance.
'Once the diameter exceeds 1.2m, steel comes into its own, ' says engineer Binnie & Partners (Overseas) director John Grimes. 'It's cheaper, stronger, lighter, easier to repair and when you're dealing with a pressure head of 600m, the welded joints perform far better than any concrete locking system.'
Practically every ground condition will be met along the route, with rock, dunes, clay, sand and an estuary-like area presenting an added corrosion issue.
Although the overland pipeline will be almost entirely buried, four major river crossings will need to be negotiated by pipe bridges.
A 170,000m 3balancing reservoir will be built at the dam to allow greater operational flexibility and before transfer, the water passes through an initial treatment works where circular clarifiers and rapid gravity sand filters will reduce the level of sedimentation and chlorination will disinfect and remove acidity.
The pipeline is protected internally by layers of epoxy coating and externally by bitumastic coating, giving an assumed 60 year design life.
A booster pumping station downstream of the treatment works will increase the transfer capacity of the overland pipe.
Conventional horizontal split casing pumps will be used, as they allow varying flow conditions and have standby provisions for repair and maintenance.
This is augmented by surge control pressure vessels, which are incorporated at an intermediate site 250km down the line and at the coastal station. Further chemical dosing at these lower stations removes biofilm.
At the coastal station flow feeds into another balancing reservoir, then picked up three 1.42m diameter submarine pipes with a horizontal multistage high pressure split casing pump.
A concrete outer lining provides extra protection, primarily increasing the mass of the pipe to anchor it to the seabed.
Trenches will be prepared by a giant Japanese-owned dredger, one of the largest in the world. In shallower waters of around 20m depth the pipes will be buried.
Final destination is a water transfer terminal on the coast of Kuwait. Its chambers contain cleaning devices, isolating valves, measuring equipment and communications systems to the control centre in Iran.
Reservoir storage, additional water treatment and pumping is provided by Kuwait's Ministry of Electricity & Water.
Completion is expected in 2005. 'But already we've faced delays due to government changes and ministerial reorganisations, 'says Clark. 'That's just something you come to expect operating in the region.'
On the ground Kuwaiti and Iranian private finance will each account for 35% of the total cost of the project with the remainder raised internationally.
Project co-ordinator Gulf Utilities is employing Binnie & Partners (Overseas) as its consultant design engineer for this scheme. No contractors have yet been appointed.
Binnie is no stranger to this field of work with experience of large scale pipeline projects in places such as Bahrain, Botswana, Saudi Arabia, Jordan and Algeria.
Theories that the next internal Middle East war will be fought over water supply were rebuffed by Binnie director John Grimes, 'It's far more likely that by adopting such schemes these countries can come much closer together.'
Gulf Utilities' Brian Hendry agrees, citing the positive response and working relationship with the Iranian authorities. 'In recent years Iran seems to be becoming far more open and increasingly keen to work with its neighbours and the international community, ' he says.