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Wing Water, UK
A new 800mm diameter steel pipe installed alongside the original pipe in the draw-off tunnel feeds the new pumping station. Old and new pumping stations are cross-connected, improving resilience by enabling raw water supply to be maintained in the event of single point failure
Innovation and collaboration have played major roles in delivery of
Anglian Water’s huge Wing abstraction and treatment project.
The UK’s largest recent water project aims to efficiently deliver secure water supplies to the growing towns of the UK’s South Midlands region. Milton Keynes, Bedford, Northampton, Corby, Wellingborough and Kettering were earmarked by the government for intensive development in 2001, but Anglian Water was already anticipating increasing demand for water in the 1990s. In 1999 the company submitted a planning application to increase water treatment at its Wing Water Treatment Works in Rutland by a third, from 270Ml/day to 360Ml/day, also increasing abstraction from the UK’s largest manmade reservoir, Rutland Water.
Anglian Water’s proposals included construction of a second pumping station at the reservoir’s east end and installation of a new pipeline carrying raw water south to a new treatment works, a literal stone’s throw from its existing works at the village of Wing. From Wing, a 34km treated water pipeline connected to existing reservoirs at Hannington in Northamptonshire.
There was concern about the 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 wouldn't impact on birdlife, so needed to put in compensation and mitigation measures.”
Nine lagoons were designed, providing 80ha of shallow water habitat, the level of which would be maintained and controlled even during periods of severe drought. Having satisfied environmental regulators, Anglian Water still needed to convince residents that the lagoons would not detrimentally alter views of Rutland’s landscape and adversely affect local tourism.
A second planning application was made in 2005, followed by two years of intense negotiation and further revision and resequencing of the planned construction programme. Anglian Water appointed us to resolve issues and develop detailed design. The proposals were finally approved in 2007.
The pace of progress through planning and consultation is in stark contrast to the speed of delivery. Civils works – pumping station, treatment works and pipeline and 35ha of lagoons – were completed in spring 2009. Mechanical and electrical installation took eight months, with operation commencing in 2010.
Building on previous experience, Anglian Water incentivised the delivery teams through a jointly developed, integrated pain/gain mechanism. A target cost was agreed for each component of the project. Anglian Water, Mott MacDonald and the three contractors then collaborated across the project to achieve savings through innovation, value engineering, procurement and continual constructive challenge. Gains made on any part of the project were shared across the teams. By turn, contractors shouldered a higher proportion of risk.
The commercial model linked everybody together. All were encouraged to pitch in and share knowledge and resources. Joint procurement meetings were held. Works were programmed so that any materials surplus from one package could be used on another. There was intense focus on recycling and reusing materials across the project. Plant, site compounds, materials stockpiles and resources such as site concrete batching facilities were all shared.
Anglian Water sought to minimise whole life costs by adopting a risk and value based approach to decision making throughout development of the project. Selection of reliability-critical plant and equipment was ultimately made after evaluating the risk of failure.
Higher capital investment was made where this contributed to lower operating costs or carbon footprint, or enhanced reliability and security of supply. Contractors were incentivised to find ways of maximising efficiency through an operational expenditure optimisation process, sharing in opex efficiencies for at least two years. This helped reduce anticipated chemical consumption, future energy bills and operational carbon emissions.
Six lagoons were 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, were created by driving sheet piled walls clad in rock armour.
The lagoons 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 showed a real commitment to working with the community and good relationships were maintained during the construction phase, with swift responses to any concerns raised by residents.
Creation of the lagoons was staggered so that impact on birdlife was minimised. Cut and fill was balanced in a total 220,000cu m muck shift. Clay won during excavation was used to line the lagoons. Environmental work included uprooting and replanting a tree used as a roost by rare pipistrelle bats, using recycled telegraph poles as perches for Rutland’s celebrated osprey colony, collecting and relocating more than 400 newts and working around a badger set. The remains of an early Iron Age dwelling were unearthed and will be rebuilt nearby.
The choice of high-inertia raw water pumps provides a significant whole life cost saving. They store kinetic energy, resulting in a gradual build-up or loss of flow, meaning no additional surge protection is needed in the pumping system. This enabled conventional surge vessels to be eliminated from the pumping station design.
All 7km of the raw water pipeline and 15km of the treated water pipeline are of 1000mm diameter pipe. The remaining 19km of treated water pipeline is 900mm diameter.
Pipe laying continued seven days a week without delays. Anglian Water deployed a full time land agent to liaise with landowners and occupiers, helping address any concerns that arose about access and the quality of final reinstatement. Highways authorities, Network Rail and the Environment Agency were also consulted: there were 30 road crossings as well as rail and river crossings along the route of the new pipeline.
In line with the environmental impact assessment, archaeological and ecological surveys and mitigation works were carried out along the pipeline easement in advance of topsoil stripping. Pipes were laid on a bed of imported granular material which the supplier deposited at agreed points along the easement – normally material would be offloaded at a single location. This eliminated the need for double-handling and saved significant time. Imports of pipe bedding material and disposal of excavated material were both reduced by using an Allu screening bucket to process excavated material, creating a homogenous backfill.
GTM’s construction contract for the new water treatment works was on a design and build basis. To encourage a consistent approach and capitalise on our experience as client’s designer, we were appointed by GTM to provide civil design. We reviewed the feasibility design and changed the process and layouts to reduce the construction programme, capex and opex costs. The savings were achieved through challenge and close collaboration between Anglian Water, GTM, Mott MacDonald, process designer Earthtech and the wider supply chain.
Major savings were made following a three month review of the concept design which integrated all parts of the treatment works into two buildings and revised the hydraulic gradient, eliminating the need for pumping between the different treatment stages. Ground level under the treatment works inlet was raised by 5.5m, using material was won from a 70,000cu m bund on the site. The treatment works is arranged on a slope, with water gravitating from the inlet through the entire treatment process.
Because ground level was higher, we ended up installing longer piles, but the cost of piling will be more than offset by the reduced whole life operating costs. Piling subcontractor Bachy Soletanche installed 550 bored, cast in situ concrete piles of 600mm diameter, up to 25m in length. Ground conditions were unusual. The treatment works sits on the edge of a glacial depression filled with soft moraine material. Decent bearing capacity was found 15m or so down, when the piles entered underlying clay.
The pile raft supports a heavily reinforced concrete structure, incorporating 2000t of rebar and 17,000cu m of C35 concrete. To minimise construction joints, concrete pours were large. GTM used Kwikastrip prefabricated continuity reinforcement and quick couplings to join rebar, aiding speed and quality. The project team was at pains to avoid hydrocarbon contamination of any of the structures during construction. For example, scissor lifts had plastic wheels that were lubricated with vegetable grease. They were electrically operated, powered by generators sited in a specially contained off-site compound.
Client’s designer: Mott MacDonald
Design and build contractor for water treatment works and pumping station: GTM – Galliford Try/Imtech JV, with design by GTM, Earthtech and Mott MacDonald
Pipeline contractor: JN Bentley
Habitats creation contractor: Carillion
The UK’s largest recent water project aims to efficiently deliver secure water supplies to the growing towns of the UK’s South Midlands region. Milton Keynes, Bedford, Northampton, Corby, Wellingborough and Kettering were earmarked by the government for intensive development in 2001, but Anglian Water was already anticipating increasing demand for water in the 1990s. In 1999 the company submitted a planning application to increase water treatment at its Wing Water Treatment Works in Rutland by a third, from 270Ml/day to 360Ml/day, also increasing abstraction from the UK’s largest manmade reservoir, Rutland Water.
Anglian Water’s proposals included construction of a second pumping station at the reservoir’s east end and installation of a new pipeline carrying raw water south to a new treatment works, a literal stone’s throw from its existing works at the village of Wing. From Wing, a 34km treated water pipeline connected to existing reservoirs at Hannington in Northamptonshire.
Adding resilience
As well as enabling increased water flow, the plan to duplicate pumping stations, pipelines and treatment works improved supply resilience against potential failure in any part of the existing system and enhanced operational flexibility. This helped ensure a continuous flow of water to customers, should problems be encountered on any part of the network.Providing environmental safeguards
But before planning approval could be granted, some major hurdles had to be overcome. The proposed route affected 114 landowners and occupiers who needed reassurance that pipe laying would cause minimum disruption and that their land would be left unscarred. The Wing treatment works itself sits prominently on top of a hill, so the visual impact had to be carefully considered.There was concern about the 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 wouldn't impact on birdlife, so needed to put in compensation and mitigation measures.”
Nine lagoons were designed, providing 80ha of shallow water habitat, the level of which would be maintained and controlled even during periods of severe drought. Having satisfied environmental regulators, Anglian Water still needed to convince residents that the lagoons would not detrimentally alter views of Rutland’s landscape and adversely affect local tourism.
A second planning application was made in 2005, followed by two years of intense negotiation and further revision and resequencing of the planned construction programme. Anglian Water appointed us to resolve issues and develop detailed design. The proposals were finally approved in 2007.
The pace of progress through planning and consultation is in stark contrast to the speed of delivery. Civils works – pumping station, treatment works and pipeline and 35ha of lagoons – were completed in spring 2009. Mechanical and electrical installation took eight months, with operation commencing in 2010.
Maximising benefits through delivery
Anglian Water is one of the construction industry’s most innovative clients. Construction partner selection was based on technical ability and demonstrable collaborative behaviour. We were engaged to support the contractors: GTM, a joint venture between Galliford Try and Imtech Process, secured the contract for construction of the pumping stations and treatment works. JN Bentley was awarded the contract for pipeline installation. Carillion was awarded the habitats creation package. Construction work started on the £117M scheme at the tail end of 2007.Building on previous experience, Anglian Water incentivised the delivery teams through a jointly developed, integrated pain/gain mechanism. A target cost was agreed for each component of the project. Anglian Water, Mott MacDonald and the three contractors then collaborated across the project to achieve savings through innovation, value engineering, procurement and continual constructive challenge. Gains made on any part of the project were shared across the teams. By turn, contractors shouldered a higher proportion of risk.
The commercial model linked everybody together. All were encouraged to pitch in and share knowledge and resources. Joint procurement meetings were held. Works were programmed so that any materials surplus from one package could be used on another. There was intense focus on recycling and reusing materials across the project. Plant, site compounds, materials stockpiles and resources such as site concrete batching facilities were all shared.
Anglian Water sought to minimise whole life costs by adopting a risk and value based approach to decision making throughout development of the project. Selection of reliability-critical plant and equipment was ultimately made after evaluating the risk of failure.
Higher capital investment was made where this contributed to lower operating costs or carbon footprint, or enhanced reliability and security of supply. Contractors were incentivised to find ways of maximising efficiency through an operational expenditure optimisation process, sharing in opex efficiencies for at least two years. This helped reduce anticipated chemical consumption, future energy bills and operational carbon emissions.
Ecological and environmental enhancement
Nine lagoons, totalling 80ha, have been 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 were 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, were created by driving sheet piled walls clad in rock armour.
The lagoons 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 showed a real commitment to working with the community and good relationships were maintained during the construction phase, with swift responses to any concerns raised by residents.
Creation of the lagoons was staggered so that impact on birdlife was minimised. Cut and fill was balanced in a total 220,000cu m muck shift. Clay won during excavation was used to line the lagoons. Environmental work included uprooting and replanting a tree used as a roost by rare pipistrelle bats, using recycled telegraph poles as perches for Rutland’s celebrated osprey colony, collecting and relocating more than 400 newts and working around a badger set. The remains of an early Iron Age dwelling were unearthed and will be rebuilt nearby.
High performance pumping station
Water is abstracted from Rutland Water via a draw-off tower and tunnel, then transferred via a new pumping station to the new treatment works. A new 800mm diameter steel pipe installed alongside the original pipe in the draw-off tunnel feeds the new pumping station. Old and new pumping stations are cross-connected, improving resilience by enabling raw water supply to be maintained in the event of single point failure.The choice of high-inertia raw water pumps provides a significant whole life cost saving. They store kinetic energy, resulting in a gradual build-up or loss of flow, meaning no additional surge protection is needed in the pumping system. This enabled conventional surge vessels to be eliminated from the pumping station design.
Pipeline
After detailed investigation in advance of awarding the pipeline installation contract, the project team determined that ductile iron pipe was 20% more economical to supply and lay than alternatives. Contractor JN Bentley worked with pipe supplier Saint Gobain on the logistics of importing 6000 pipes from France.All 7km of the raw water pipeline and 15km of the treated water pipeline are of 1000mm diameter pipe. The remaining 19km of treated water pipeline is 900mm diameter.
Pipe laying continued seven days a week without delays. Anglian Water deployed a full time land agent to liaise with landowners and occupiers, helping address any concerns that arose about access and the quality of final reinstatement. Highways authorities, Network Rail and the Environment Agency were also consulted: there were 30 road crossings as well as rail and river crossings along the route of the new pipeline.
In line with the environmental impact assessment, archaeological and ecological surveys and mitigation works were carried out along the pipeline easement in advance of topsoil stripping. Pipes were laid on a bed of imported granular material which the supplier deposited at agreed points along the easement – normally material would be offloaded at a single location. This eliminated the need for double-handling and saved significant time. Imports of pipe bedding material and disposal of excavated material were both reduced by using an Allu screening bucket to process excavated material, creating a homogenous backfill.
Reliable and robust treatment works
Robust treatment processes are crucial to Anglian Water. They desired innovation but needed assurance against risk nonetheless.GTM’s construction contract for the new water treatment works was on a design and build basis. To encourage a consistent approach and capitalise on our experience as client’s designer, we were appointed by GTM to provide civil design. We reviewed the feasibility design and changed the process and layouts to reduce the construction programme, capex and opex costs. The savings were achieved through challenge and close collaboration between Anglian Water, GTM, Mott MacDonald, process designer Earthtech and the wider supply chain.
Major savings were made following a three month review of the concept design which integrated all parts of the treatment works into two buildings and revised the hydraulic gradient, eliminating the need for pumping between the different treatment stages. Ground level under the treatment works inlet was raised by 5.5m, using material was won from a 70,000cu m bund on the site. The treatment works is arranged on a slope, with water gravitating from the inlet through the entire treatment process.
Because ground level was higher, we ended up installing longer piles, but the cost of piling will be more than offset by the reduced whole life operating costs. Piling subcontractor Bachy Soletanche installed 550 bored, cast in situ concrete piles of 600mm diameter, up to 25m in length. Ground conditions were unusual. The treatment works sits on the edge of a glacial depression filled with soft moraine material. Decent bearing capacity was found 15m or so down, when the piles entered underlying clay.
The pile raft supports a heavily reinforced concrete structure, incorporating 2000t of rebar and 17,000cu m of C35 concrete. To minimise construction joints, concrete pours were large. GTM used Kwikastrip prefabricated continuity reinforcement and quick couplings to join rebar, aiding speed and quality. The project team was at pains to avoid hydrocarbon contamination of any of the structures during construction. For example, scissor lifts had plastic wheels that were lubricated with vegetable grease. They were electrically operated, powered by generators sited in a specially contained off-site compound.
Safety
Health and safety was underpinned by a charter, the guiding principle of which was: Nothing is so important that we can’t take time to do it safely. There was close attention to the reporting of near misses. Individual contractors backed the project charter with their own health and safety procedures and initiatives. A cross-project safety forum, with representatives from each of the delivery partners, ensured that best practice was adopted across the Wing programme and provided a focus for continuous improvement.Who’s who
Client: Anglian WaterClient’s designer: Mott MacDonald
Design and build contractor for water treatment works and pumping station: GTM – Galliford Try/Imtech JV, with design by GTM, Earthtech and Mott MacDonald
Pipeline contractor: JN Bentley
Habitats creation contractor: Carillion