The UK’s largest current water project is a scheme to expand Rutland Water and its Wing treatment works without upsetting the delicate ecological balance. NCE reports.
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The Wing abstraction and treatment project is not only the UK’s largest current water project. It is also Anglian Water’s biggest ever scheme. Collaborative working, incentives, integrated risk and opportunity management are just some of the tools being used alongside a lot of intelligent engineering to deliver the £117M project.
The scheme will provide secure water supplies to meet the growing demands from the expanding towns of Milton Keynes, Bedford, Northampton, Wellingborough, Kettering and Corby.
Anticipating this intensive growth, Anglian Water submitted its initial planning application in 1999 to increase water treatment at its Wing Water Treatment Works in Rutland from 270Ml/day to 360Ml/day. This needed increased abstraction from the UK’s largest manmade reservoir, Rutland Water, and the laying of 41km of raw and treated water pipeline.
As well as enabling increased water flow, the plan to duplicate pumping stations, pipelines and treatment works will improve supply resilience against potential failure and enhance operational flexibility.
A site of environmental importance
Inevitably concerns were raised about the potential environmental impact of increased abstraction from Rutland Water which, since its completion in 1976, has become a site of significant environmental importance. Anglian Water programme manager Steve Swan explains: “It supports lots of wildlife − particularly birdlife − and is now a Special Protection Area, Site of Special Scientific Interest and a Ramsar Site. If we took more water from the reservoir its level would fall further during drought events. We had to demonstrate that increased abstraction would not impact on birdlife, so needed to put in compensation and mitigation measures.”
Anglian Water, working with Halcrow, designed nine lagoons, providing 80ha of shallow water habitat, the level of which would be maintained and controlled even during periods of severe drought, acting as a secure habitat for wildlife.
“We had to demonstrate that increased abstraction would not impact on birdlife, so needed to put in compensation and mitigation measures.”
Steve Swan, Anglian Water
When the second planning application went in in 2005 Anglian Water appointed Mott MacDonald to develop the delivery approach, help resolve issues, provide programme management and environmental services and develop detailed design during two years of intense negotiation and resequencing of the programme. The planning application was finally approved in 2007 and the project officially launched by Sir David Attenborough in February 2008 (NCE 16 April 2008).
The pace of progress through planning and consultation is in stark contrast to the speed of delivery. By April 2009, 39km of pipeline, 35ha of lagoons and all the treatment work’s structures have been completed. Mechanical and electrical installation is underway, and water into supply is planned for Spring 2010.
GTM, a joint venture between Galliford Try and Imtech Process, won the contract for detailed design and construction of the pumping stations and treatment works; JN Bentley was awarded the contract for pipeline installation; and Carillon was awarded the habitats creation package.
Sharing knowledge and resources
Anglian Water incentivised the delivery teams through a jointly developed, integrated pain/gain mechanism. Gains made on any part of the project will be shared across the teams. By turn, contractors have shouldered a higher proportion of risk.
“The commercial model links everybody together,” comments Swan. “Everybody is encouraged to pitch in and share knowledge, resources and best practice.”
Joint procurement meetings are held and works have been programmed so that any materials surplus from one package can be used on another. There has been intense focus on recycling and reusing materials across the project. Plant, site compounds, materials stockpiles and resources such as site concrete batching facilities are all shared.
Anglian Water has sought to minimise whole life costs. The business is happy to consider higher capital investment where this will contribute to lower operating costs, carbon footprint, or enhanced reliability and security of supply. Contractors are incentivised to find ways of maximising efficiency sharing in operational expenditure efficiencies for a minimum of two years.
Nine lagoons, totalling 80ha, are being created on Rutland Water’s western shore. The seasonal level in each lagoon, varied by a tilting weir arrangement, will attract different migratory birds.
Six lagoons are being built on land, involving construction of earth bunds up to 5m tall, which provide containment for the water and screen birds from prevailing weather and disturbance by traffic on local roads. Three ‘marine’ lagoons, impounding areas of the reservoir itself, are being created by driving sheet piled walls, which will subsequently be clad in rock armour. Piles have been driven from floating pontoons.
“Mitigating the environmental impact of the lagoons hasn’t been easy,” says Mott MacDonald project manager Quentin Rea: They will frame the view from the village of Egleton across the reservoir and have been designed with input from Natural England, the Royal Society for the Protection of Birds, the Leicestershire & Rutland Wildlife Trust and the residents of Egleton, via their Parish Council. “We optimised the shape of the lagoons to minimise the visual impact and size of the bunds. Anglian Water has shown a real commitment to working with the community and good relationships have been maintained during the construction phase, with swift responses to any concerns raised by residents.” Rea says.
“Mitigating the environmental impact of the lagoons hasn’t been easy. We optimised the shape of the lagoons to minimise the visual impact.”
Quentin Rea, Mott MacDonald
Creation of the lagoons is being staggered so that impact on birdlife is minimised, with the final lagoon scheduled for completion in 2010. Carillion is balancing cut and fill in a total 220,000m³ muck shift. Clay won during excavation is being used to line the lagoons.
Work is being carried out using a fleet of dozers, dump trucks and excavators. The dozers are fitted with GPS systems which are used to control the line, levels and profiles of the bunds and islands. “This means we don’t need engineers on site setting out and taking measurements, which greatly improves site safety,” says Carillion contracts manager Dave Hutchinson. “When you’ve got more than a dozen pieces of plant operating at once you don’t want to mix men and machines.”