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Desert epic

Irrigation Egypt: The new millennium heralds the age of vast water projects. Kvaerner is working on just one such in the Egyptian desert, says Adrian Greeman.

Read this if you are interested in major irrigation projects.

you want to hear about out of the ordinary excavation techniques.

you want to know about working in extreme conditions.

you have an interest in developing economies.IN A BURNING hot moonscape, huge machines and hundreds of men are toiling round the clock to create a vast monument in the desert. This is Egypt, but the structure is not a pyramid, a funeral monument for the Kingdom of the Dead: its aim is to bring life.

In four years the huge new Mubarak pumping station, possibly the world's largest, will pour millions of cubic metres of water into a canal winding across the desert in southern Egypt, creating a vast area of green fields and small towns. Some 7M people will make their homes in the total $1.8bn South Valley Development Project in the Toshka region.

But creating the oasis, a personal dream of Egyptian President Hosni Mubarak, is tough work. The environment is a hostile one, especially in summer when temperatures rise to an almost unbelievable 50degreesC plus. And there is nothing at all yet in this desert zone except for the modern watery relief of the nearby Lake Nasser, the Nile reservoir held back by the giant Aswan High Dam.

'All we have round here are donkeys, pelicans and a few fishermen,' says Eddie McEwan, project director for Norwegian owned British contractor Kvaerner Construction. 'That and the odd crocodile, though I have only seen those in the Abu Simbal reptile zoo. It is the remotest place I have been in my life.'

Kvaerner is lead contractor in a consortium of three firms carrying out the $435M design and build project. It has a 48% stake while local firm Arabian International Construction (AIC) has 27% and Japan's Hitachi 25%. The latter's contribution is the 21 huge pumps themselves, 16.7m 3/sec capacity units which will lift 25M.m 3/day of water from Lake Nasser a height of 50m into the 70km long Sheikh Zayed Canal. AIC is concentrating on the pumping station excavation and concreting while Kvaerner's preoccupation is with the giant intake channel.

Kvaerner has German engineer Lahmeyer on board along with Egyptian firm Hansa. The client, the Egyptian Ministry of Public Works and Water Resources, has appointed French firm Sogreah as checking engineers.

According to McEwan the channel is of unprecedented size and capacity for an inland project. It is nearly 50m deep, trapezoidal in cross section and extends 4.7km out into Lake Nasser.

The first 1.6km length is being built in the dry but the rest must be excavated through the sloping bed of the lake.

'We have built a sheet pile coffer dam at chainage 1600m,' he says, so that some of the work can proceed in the dry.

Unsurprisingly the ground consists mainly of medium to soft sandstone.

There are also layers of siltstone and claystone and bands of very hard ironstone in places.

To get through the longer, underwater section Kvaerner is using two huge Liebherr backhoes mounted on dredgers. The first, a 380t P995 capable of digging to a maximum 27m, has now been working for some time. The second is being assembled after its long journey from Liebherr's Colmar factory in France. This is a 480t P996, one of the largst excavators on the market, and, as McEwan says, 'fundamentally awesome'.

Bringing in the units has been one of the big challenges of the job, says McEwan. 'The supply chain into here is problematical.' There is a specially built project road leading to the site from Abu Simbel, site of the temple of Ramses II, but that is only the last 250km of the long journey from the Red Sea.

Machines, and sections of the split hopper barges being used for spoil transfer, were offloaded at Safaga port after passing through the Suez Canal.

Weighing up to 90t, the loads had to pass down a coast road and traverse a number of villages before embarking on the 230km desert crossing. The high temperatures caused frequent tyre blowouts on the multi axle carriers.

'The elements are not simply heavy but bulky,' says McEwan. Some were as much as 8m across and this created problems when passing through some villages and small communities. McEwan says the priority given to the project by President Mubarak has helped, and communities were highly cooperative, being ready to move lampposts, walls and small huts to get loads through.

Kvaerner built a small by-pass around one village.

The pontoon for the P996 was being fabricated last month at a small shipyard at Aswan. Despite the seemingly remote location near the Sudanese border, McEwan says the workmanship is astonishingly good.

The specially equipped P996 will operate a maximum depth of 38m, which Liebherr claims as a world record. At this depth bucket capacity will be a mere 3m 3rather than the standard 10m 3. Breakout force is still an impressive 450kN. 'We will also do some blasting in the deeper parts of the channel,' says McEwan. A Rohr grab dredger will be used to muck out the deepest part.

Bringing in the plant and equipment has cost Kvaerner more time than it would like and it is a 'notional few months' behind on the wet excavation, says McEwan. He is confident that the time can be made up, especially now the cooler season is here. In the hottest season, midday work is ruled out and night shifts are necessary. The dry work is going well and altogether some 2M.m 3of a 10M.m 3excavation has been completed. There is another three years to run.

Meanwhile AIC has completed the excavation for the pumping station itself and is beginning work on the 200,000m 3of concrete work. Concrete is produced on site in a pair of Elba and Arbau batching plants. The consortium also produces its aggregate supplies which are stockpiled in the shade and sprayed with chilled water before mixing. During next summer's high temperatures the ice-making plant will come on stream to provide cooling for the concrete.

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