Cambridgeshire

Welney Ouse Washes reservoir flood defence work enters third phase

Ouse Washes Image copyright Environment Agency
Image caption The Ouse Washes flood storage reservoir runs between two drainage channels and stretches for 22 miles in Cambridgeshire and Norfolk

The latest phase of a four-year plan to raise the banks of a 22-mile (33km) flood reservoir will begin within weeks.

The Environment Agency is leading a £27m project to strengthen and protect the man-made banks of the Ouse Washes reservoir in the Cambridgeshire fens.

The work, which began in 2017, is taking place over four summers to avoid disturbing breeding wildlife.

When full, the reservoir holds enough water to fill Wembley Stadium 22 times.

Image copyright WWT
Image caption Birds including the black tailed godwit (left) and wigeon are regular visitors to the Ouse Washes
Image copyright Environment Agency
Image caption The banks are being raised to strengthen and stabilise the flood defences

The reservoir - stretching from Earith near St Ives in Cambridgeshire to Downham Market in Norfolk - was built in 1653 by the Dutch engineer Cornelius Vermuyden, during a programme to reclaim fenland from periodic flooding.

Every year it protects thousands of properties, roads and railways - as well as 67,000 hectares of farmland - on the surrounding lower-lying land from winter flood water.

However, an inspection in 2013 identified problems with the safety and stability of the Middle Level Barrier Bank - (where the Welney Wash road crosses the reservoir. )

Image copyright Environment Agency
Image caption The work is taking place over four summers - with the third stage starting in July

"Our objective is to maintain the high level of flood protection we provide to communities living near the Ouse Washes," said an Environment Agency spokesman.

"Our recent assessment of the bank height shows flood water could overtop the bank at isolated locations in the equivalent of a 1% probability event."

Image copyright Environment Agency
Image caption The Welney Wash road, which crosses the reservoir between the village of Welney and Gold Hill, is regularly shut because of flooding

The Environment Agency is raising the bank between Earith and the Welmore Lake Sluice.

The area, which is rich in wildlife including wintering swans, geese and ducks, has international conservation status and is peppered with wetland nature reserves.

As a result, the work has been taking place between mid-July and October to protect breeding species.

Image copyright Google
Image caption The third stage of work to raise the banks of the Ouse Washes takes place between Mepal and Welney this summer

Construction will start on phase three on 15 July.

Image copyright Environment Agency
Image caption A flood barrier, with "planks" which can be inserted between posts and then removed (similar to the one pictured), will be built on the A1101 next year

A "demountable barrier system" will be built at the flood-risk A1101 Welney Wash road in 2020. It can be used to limit the effect of rising waters and would be put up each time Norfolk County Council closes the road to traffic.

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