Your browser is no longer supported

For the best possible experience using our website we recommend you upgrade to a newer version or another browser.

Your browser appears to have cookies disabled. For the best experience of this website, please enable cookies in your browser

We'll assume we have your consent to use cookies, for example so you won't need to log in each time you visit our site.
Learn more

Jon's blog - Flooding: learning the lessons

There were a multitude of issues faced in this summer’s floods but in my opinion the key problems were based around storm water drainage standards, maintenance, flood defence of critical infrastructure, and overall responsibility. Jon Robinson is associate director in Scott Wilson’s Water Group

The independent review led by Sir Michael Pitt will examine both how to reduce the risk and impact of floods, the emergency response conducted and future revisions, and the viewpoints of those affected. These terms of reference used for the review are standard but diverse stipulations, covering flood risk management, vulnerability of critical infrastructure, emergency measures and planning, and issue management.

The widespread flooding of urban centres, in particular as seen in Hull, was likely to be attributable either to a failure of storm water drainage to cope with rainfall intensity or the blockage of drains (often due to poor maintenance), or even both. The storm water drainage standard is still generally based on a 1 in 30 year standard. This was not explicitly revised in the PPS25 and one that should be considered for future development.

Flood risk due to the failure of drainage systems has never been comprehensively mapped, as done so for rivers and tides. Drainage ‘catchment’ scale studies need to be implemented for identified areas through pre-screening. The potential for widespread flooding can consequently be identified via this mechanism.

Maintenance responsibility for drainage systems falls across too many parties, such as local authorities, the Environment Agency, Internal Drainage Boards, county councils and private individuals. Consideration should be given to reclassifying drainage systems and assigning responsibility for their coordination and maintenance to as few parties as possible. Funds need to be made available for the basic function of cleaning out drains and ditches, and this should be organised centrally.

Meanwhile, the importance of defending essential infrastructure was underlined by the events at Walham Power Station in July. PPS25 now defines ‘essential infrastructure’ and advocates location of this outside of flood zone 3. However, for existing essential infrastructure there should be a coordinated review of flood risk with the aim of prioritising locations where additional flood defence is or may be necessary. I call this the ‘critical’ infrastructure review.

Much of the proposed review will also focus on the wider emergency response. Although on the ground emergency services clearly did all they could, there was a suspicion that the coordination of the emergency response was hampered by general misinformation and misunderstanding of who has overall responsibility. For example, flood defence sits with DEFRA, but flood planning with DCLG. The emergency services on the ground were taking advice from the Met Office, the EA and the local authority. I would like to see the development of clear lines of responsibility in the event of a flood. This would also aid the planning of future development – many site-specific FRA’s currently second-guess the likely emergency response locally.

Have your say

You must sign in to make a comment

Please remember that the submission of any material is governed by our Terms and Conditions and by submitting material you confirm your agreement to these Terms and Conditions. Please note comments made online may also be published in the print edition of New Civil Engineer. Links may be included in your comments but HTML is not permitted.