Flood warning

Poor drainage and a big rise in basement extensions threaten two top boroughs reports Mira Bar-Hillel

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More than 400 homes, 13 schools and public buildings were flooded during the July storms in Kensington & Chelsea alone. A council report out this week tells of the failure of drainage and sewerage systems to cope with the flash flooding.

Kensington & Chelsea and Hammersmith & Fulham were the boroughs worst affected by this summer’s deluge.

Thames Water and watchdog Ofwat have come under fire for not providing households with the equipment to prevent extensive damage, even though previous severe floods in 2004 and 2005 had thrown up weaknesses in the infrastructure.

After the severe floods in September 2005 Thames Water fitted a non-return valve on the main sewer. As a result, homes were still flooded in July, but only with rain water. The council is now recommending that Thames Water and Ofwat install back-flow valves in all the borough’s households.

The growing number of basement extensions is adding to the flood risk. Kensington & Chelsea has commissioned an engineering report on the capacity of these extensions to handle heavy downpours.

In Hammersmith & Fulham, where even worse flooding was reported, all home-owners who apply for planning permission for basement extensions are already required by the Environment Agency to produce flood-risk assessments. More than 250 applications are currently being delayed for up to three weeks each by the Environment Agency while it makes its decisions.

The council’s cabinet member for environment, Nicholas Botterill, is critical of the process. He says: “The Environment Agency simply doesn’t have the capacity to process all the applications it will be receiving. Its guidance on what a flood-risk assessment should be is over-complex and unhelpful to home-owners.”

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