Royal opening for 'natural' Jubilee River
JUBILEE RIVER, the award-winning £90M Maidenhead, Windsor & Eton Flood Alleviation Scheme, was officially opened by HRH Prince Andrew this week.
At an opening ceremony attended by over 200 invited guests and members of the public, the Prince was quick to praise the engineers who had made the scheme happen.
'I add my congratulations to those involved at the start who had the concept, and those who had the drive to push the project through, ' he said.
The Duke of York was joined on the dais by ICE stalwart Jean Venables who, as chairman of the Thames Regional Flood Defence Committee, has led the scheme virtually from day one, through almost 20 years of planning, design, public inquiry and construction.
The scheme, the Environment Agency's biggest ever inland flood defence project, is a new 11.6km man made channel.
Together with 5km of flood banks, the channel is designed to protect up to 12,000 people from flooding by augmenting the capacity of the Thames in the area by 222m 3/s.
On average, flooding from the Thames occurs in Maidenhead every five to seven years. The last major flood happened in 1947, when over 2,000 homes were affected.
Statistically a flood on this scale has a one in 56 chance of happening in any one year, and should it happen today 5,500 homes would be affected.
Jubilee River has been designed to cope with just this event.
The new channel begins in the Maidenhead area, then runs east of the Thames through Taplow, rejoining the river downstream of Eton. The route is crossed by three railways and several roads, including the M4.
The channel is intended to look and act like a natural river, using a base flow of 10m 3/s taken from the Thames. It has been specifically designed to replace habitats and breeding areas previously lost.
The route has also been designed for recreational use, with the National Cycle Network route number 61 running alongside.
The project was first proposed in 1983, with planning, design and a public inquiry lasting 14 years.
Six years ago, the ICE recognised the design, making it the first winner of the Edmund Hambly Award for 'creative design of an engineering project that makes a substantial contribution to sustainable development.
Construction began in 1997.
The biggest and most expensive challenge was passing the river beneath the four-track Paddington to Reading main line without disrupting services or causing the embankment to subside.
The solution was to freeze a section of the embankment to -30infinityC, before the new bridge was pushed forward by 36 jacks mounted in six jacking trenches in the base slab.
If the bridge had ever stopped moving there was a risk of the embankment settling onto it, so jacking had to continue 24 hours a day for six weeks until the bridge was in position.
Passing beneath the M4 was equally challenging. All six lanes were diverted to allow a bridge to be built and the motorway restored on top.
Contaminated land was a major issue, with the route passing through a 19th and 20th century industrial waste disposal ground and a disposal site for sewage sludge from the nearby Slough sewage treatment works.
With a significant danger of heavy metals entering the Thames, the Environment Agency decided to construct a secure, 5.6ha containment cell above the groundwater table.
The cell houses 135,000m 3 of contaminated material, topped by 2m of soil to allow grass and trees to grow.
Despite delays caused by the wet winter of 2000/01 the scheme was substantially completed by late summer 2001, allowing Venables to perform the ceremonial opening of Taplow Weir in September.
It was used for the first time for flood defence this February, when one of three weir gates was opened to prevent the Thames overtopping its banks and flooding an estimated five properties.
'To design a scheme that looks so natural - even in its infancy - is innovative. I am very proud of this project as not only does it reduce flood risk but also provides leisure and recreational facilities and reintroduces habitats, ' said Venables.
'It is very hard to get the headlines for schemes that are successful, because people have expectations of us, ' continued Venables. 'So I hope that the only headlines we see here are the return of the water vole or the otter to Windsor and Maidenhead.'
Source document: http://www.nce.co.uk/royal-opening-for-natural-jubilee-river/803051.article - no longer supported