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Tidal power lagoon could protect Somerset Levels

A power firm is drawing up plans for a tidal lagoon that could also work as a flood management scheme for the Somerset Levels.

Tidal Lagoon Power, which last month handed over a planning application for the UK’s first tidal power scheme in Swansea Bay, is considering a similar project in the Severn Estuary.

Although it would be built primarily for power generation, the firm has indicated it would seek to maximise the Bridgwater lagoon’s ability to reduce flooding on the Somerset Levels.

Construction of such a barrage forms part of Somerset County Council’s 20 year action plan (see box, below).

This deluged area of the West Country has been under the media spotlight for weeks, with expensive pumping and dredging operations sanctioned by the government.

“During incidence of flooding, it may be possible to manage the operating cycle of a tidal lagoon so that the structure holds back the sea on peak spring tides, creating a short-term temporary reservoir to help with drainage of low-lying areas, as well as creating a steeper gradient to encourage run-off from the land and rivers in the area behind the lagoon,”said Tidal Lagoon Power.

Critics of the government- sanctioned plan to dredge the rivers Parrett and Tone to alleviate the flood risk to the Levels have backed construction of a lagoon.

Cardiff University professor of water management Roger Falconer has questioned the need for dredging.

“All and sundry seem to think dredging will solve the problems on the Somerset Levels. But any civil engineering student would question that,” he said.

“If there is no gradient there will be no flow. You have virtually a horizontal river so dredging would have little or no effect. You need to increase the water surface slope.”

This required raising the land or, more practically, lowering the sea level, said Falconer.

“We should divert our enthusiasm to support the companies that want to develop the Bridgwater Bay Lagoon,” he said.

“Where renewable energy schemes have additional benefits for flood defence we should look sympathetically at them. We should do everything we can to get them through planning.”

Government-commissioned research led by consultant Parsons Brinckerhoff concluded in 2010 that building a lagoon in Bridgwater Bay would cost about £12bn.

But a Tidal Power Lagoon spokesman said: “We have found ways to significantly reduce the construction cost.”

Bridgwater Bay is one of 11 sites the firm is examining, with a view to developing five of them over the next decade.

Extra roads cash kicks off 20 year flood action plan for Somerset

Somerset County Council has revealed how it intends to use a £10M grant from the Department for Transport for tackling floods on roads.

The funding for the roads could see a series of projects get underway including work to repair bridges and other structures, the rebuilding and resurfacing the roads using more flood resistant surfacing where required and the installation of flood gates and diversionary signage to manage future flood events.

The funding will also help Somerset County Council carry out a number of transport studies to improve the resilience of the A361 across the Somerset Levels.

The roads funding was announced alongside a 20 year Flood Action Plan for the region. Environment secretary Owen Paterson announced the Plan to the House of Commons on Thursday. The Plan sets out targets and aims to prevent the same level of flooding hitting Somerset’s levels and moors that has been suffered over recent months.

It contains a number of commitments such as dredging around 8km of the River Parrett, and repairing damaged riverbanks.

The plan also contains a number of ambitions that would require significant further funding, including possible construction of a flood and tidal barrage.

 

 

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