An investigation has been launched after heavy rain flooded properties in St Ives, Cornwall, just four weeks after a new £10M flood-defence scheme was officially opened.
A freak rainfall event early on 25 April saw 40mm of rain fall in just two hours, sweeping a car down a river at nearby Zennor and drowning three of its occupants.
Around 12 business premises in St Ives were flooded, despite completion of the Environment Agency’s new scheme to prevent overtopping of the Stennack River, which has often caused flooding in the town.
A spokeswoman for Cornwall County Council said the flood defences had been overwhelmed by the volume of water, and referred inquiries to the Environment Agency.
The agency said its scheme had mostly worked well and that, had it not been implemented, around 200 properties would have been flooded. But it has instituted an inquiry involving the council and other agencies to determine what happened.
‘We need to investigate around the surface water-flooding issue,’ said an agency spokesman. ‘There is also an issue around the new pumping station at the bottom of the hill. ‘It ran for six hours and couldn’t cope with the volume of water, so we may have to look at its capacity.’
The new scheme was constructed following work on surface drains in the town centre by the county council in 2005, and involved new flood walls to increase the river capacity, new culverts, reinforced flood walls and new storm sewers.
It also employed an innovative use of cross drains to catch rainfall as it runs down the hill and divert it into culverts.
Fast-growing willow was also planted on the banks upstream of the town’s fire station to slow flood waters and prevent erosion.
The scheme won a CEEQUAL whole project award for its distinctive and exceptional environmental standards.
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