The earth bank for the dam comes from 5 million cubic metres of soil quarried from around the area. About 60,000 cubic metres of concrete is going into the reservoir and various structures in the dam. The treatment works need another 55,000 cubic metres of concrete. About 70,000 tonnes of steel piping

from France is to be laid over 100 kilometres. There will be a further 45 kilometres of ductile iron piping from the UK.

The treatment works lie southeast of Izmit. The source of water is the natural Kirazdere springs which rise in the mountains nearby. The earth- filled dam at Yuvacik, with a clay core, is a design used many times in Turkey. It will be 100 metres high, 400 metres long and will be able to store 60 million cubic metres of water, delivering about 140 million cubic metres a year into the supply system. The spillway will be controlled by four radial gates discharging into the basin.

The water will be carried five kilometres down from the dam to the treatment works via a 2.2-metre-diameter steel pipe. The plant will be capable of processing 4.5 cubic metres of water a second into drinking water. In turn, this will be distributed around an area extending as far as 80 kilometres from the treatment works down a main steel spine pipeline starting off at 2.2 metres in diameter, reducing to 1.2 metres at its furthest point.

Ductile iron pipes ranging from 800 millimetres in diameter down to 250 millimetres will feed reservoirs along the length of the route. The water pressure will be boosted by four pumping stations.

The dam will be able to hold more water than specified in the original contract and the treatment works will be capable of treating at least 25 per cent more than the specified volume.