Page last updated at 08:30 GMT, Tuesday, 13 May 2008 09:30 UK

Bridge designed to be swan-proof

Artist's impression of the revised bridge plan (from Surrey County Council)
The new bridge was designed with the help of swan experts

A new bridge spanning the River Thames in Surrey will have special features to stop swans crashing into it.

The new Walton Bridge, which was approved by Environment Secretary Hilary Benn in January, will be ivory in colour to show up against the sky.

In the past, swans have collided with the lamp columns of the old bridge because they failed to see them.

Staff at the Wildfowl and Wetlands Trust in Gloucestershire helped Surrey County Council find the best colour.

Different coloured bridges were tested against different types of sky - ranging from bright blue to dark and stormy - using computer technology.

The trust's experts at Slimbridge selected ivory as the colour most visible to the swans.

Shape of arches

"There has been a huge range of factors to consider in the design of the new bridge," said councillor David Munro.

"By tweaking the design a little we can keep safe the beautiful and elegant birds that are so much a part of the life and attraction of the river."

The shape of the arches was also designed with the swans in mind.

The cross-section of the arches were given a six-sided rather than rounded shape so they would cast shadows that the swans could pick out in flight.

As a temporary measure, when the bridge is first built, it will also have brightly coloured discs on the support rods linking the arches to the road to help the swans become familiar with the new structure.

The new Walton Bridge has been under discussion since the 1980s, but previous plans were rejected after a planning inquiry in 2006.

It is expected to be completed by 2014.


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