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Flood risk assessment requirements for planning applications

Find out when you need to do a flood risk assessment as part of your planning application, how to complete one and local useful information and relevant documents.

Flood risk assessment advice

Firstly find out if you are at risk of flooding »

Please note the provision of a flood risk assessment does not presume the application will be acceptable particularly if the site lies in the functional floodplain.

Follow the flood risk assessment for planning applications advice provided by government.

Hillingdon have written Flood Risk Assessment Guidance for minor development [123KB] for those undertaking minor development in the floodplain. Please see the attached document for information and submission with any application to demonstrate you are complying with government standing advice. 

Strategic flood risk assessment

The London Borough of Hillingdon, alongside Barnet, Brent, Ealing, Harrow and Hounslow, have produced a West London Strategic Flood Risk Assessment (West London SFRA).

This details the flood risk information available in the borough, providing evidence for ensuring development is steered away from areas identified most at risk from all sources of flood risk, reducing the risk of flooding to residents and buildings. The key differences from previous SFRAs are that it includes:

  • A new definition of the flood zone 3a: Fluvial, tidal and surface water flood risks have been included within the flood zone 3a definition to reflect the significant nature of local flood risks within the heavily urbanised boroughs.

  • An application of the sequential test and exception test: These two approaches include assessment of risk from all sources of flooding (not just fluvial and tidal as previously generally applied). It also provides guidance for windfall developments.

  • Site-specific flood risk assessments: The will be required for all development proposals in flood zones 2, 3a and 3b - noting the definition of flood zone 3b in this SFRA includes surface water flood risk. Please also find specific guidance on FRA.

  • Drainage Strategies: These are required for all major developments not categorised as 'change of use'. All minor developments and developments categorised as 'change of use' or proposed changes to previous approvals which modify existing surface water drainage will also require a drainage strategy.

The West London SFRA is now available online for public viewing.

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Article utilities:  Bookmark and Share Print Print this page Last updated: 13 Mar 2019 at 15:19