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Jewel in the crown

Isle of Man Crystal Project - The Isle of Man is replacing its entire water supply system in the £71M Crystal Project. Diarmaid Fleming reports on a landmark Manx project.

In the Laxey Wheel, the Isle of Man may have the world's largest working water-wheel, but it is another water engineering project that is preoccupying the island's water engineers.

The island, which is independent and self-governing, is not part of the UK or the EU and is therefore not legally bound by their standards.

'We don't have to follow EU standards, but we follow them as best practice. Our water infrastructure was probably lagging about 10 years behind the UK, but in the mid-1990s it became apparent that we had old, ageing, assets and treatment works, ' says Isle of Man Water Authority director of operations and chief executivedesignate John Smith.

While Brussels may have a different name for it, the legal standard governing Manx water quality is jargon-free: 'We have to demonstrate that we produce 'wholesome' water, ' explains Smith.

Water sources in the Isle of Man come from upland catchments, for example, the Sulby reservoir, set in wild bog moorland scenery as beautiful as anywhere in the British Isles.

High organic load from the catchment has warranted high levels of chlorination and its byproduct trihalomethanes (THMs), which are carcinogenic and strictly controlled.

'The rinking Water Inspectorate does not recommend reducing disinfection to reduce THMs, but we have come close to breaching certain levels, ' says Smith.

'We needed to replace the treatment works within ve years. The works we had were all single-stage treatment works and we were trying to deal with all sorts of things.

'We have a problem with manganese in the water, which is treated with chlorides and tends to precipitate out and is deposited. But if there is any disturbance in the water supply, you get blackened water - and thousands of complaints.' Polarite introduced into the old lters has helped reduced the manganese, but soon such problems will be a thing of the past.

The authority as given approval by the island's parliament in 1999 to get to work and funding of £71M provided.

In six years, £24M has been spent on work, including a new treatment works at Sulby as well as repairs and remedial works to reservoirs, pumping stations and pipelaying.

Currently under way is the £32M 'Crystal Project' covering four separate schemes: a new 7.6km raw water pipeline to feed a new 37Mld treatment works in Douglas; a new 2.5km treated water pipeline from these works; and an overow connection capable of taking a maximum instantaneous ow of 40Mld, but with balancing chambers limiting ow to 12Mld into the River Glass, which flows into the sea at Douglas.

However, it has not been all plain sailing. Planning permission was sought for both Sulby and Douglas together in 2000/1. In scenic Sulby, locals were hugely supportive and it sailed through.

In residential Douglas, however, it failed.

It had been intended that both the Sulby and Douglas works would be let together.

Sulby proceeded alone, with contractor Earth Tech awarded the contract in April 2003 with its civil/building subcontractor Charles Brand (IoM) - part of the Belfast-based Lagan Group - and engineers MWH.

But at Douglas ve objections, which grew to 12, mired the project in delays. First refusal in 2002 was reconrmed in 2003.

'The objections were mainly about noise during the operation.

Noise became a major headache for us, ' says Smith. Approval was granted only on condition that 32dB would not be exceeded.

The problems posed by the planning refusal brought unintentional 'early contractor involvement', says Smith, with the Sulby team involved. 'We had to come up with some ideas pretty quickly.' Consultant Atkins, working with Lagan in Belfast, helped develop alternative designs enabling resubmission in early 2004 before planning permission and contract award could follow in 2005.

'Sink it and shrink it became our by-words, ' says Smith.

Nimby was to become Bumby - 'not in my back yard' becoming 'build under my back yard'.

The works were sunk 7m underground and redesigned from one building to three separate subterranean structures connected by a corridor, with a structure the size of an average domestic house being the only thing visible above ground.

A mining licence was required from the Isle of Man government - as applies to all building work on the island more than 2m below ground - with 30,000t of rock shale to be removed.

'We used a pecker to excavate. Once you get a cut into the inclined beds you could get into it easily, ' says Isle of Man Water Authority assistant project sponsor Steve Babb.

The excellent quality of the rock arisings posed an unusual problem. 'The amount of material excavated was about six months' of the island's supply of Type 1 material.

'The mining licence set a minimum price for what we could sell it for, so the local market would not be ooded with cheap material, ' he says.

The aggregates tax does not apply on the island, but different market forces were applied.

'In the end we were able to barter our material with some local suppliers, so it brought benets to both, ' says Babb.

'Quite a lot of the original team who went to work on the Sulby project remained involved right through to this one, ' says Earth Tech Engineering project director Adam Bateman.

With the team working together on the planning resubmission and alternative designs, a partnership was forged in adversity.

For the rst time ever, the Authority adopted the New Engineering Contract Option C Target Cost form.

Building work is proceeding well since the contract was signed in May 2005, with a target completion date of 28 February next year.

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