Flood risk management

Flooding can come from various sources, from coastal waters, from rivers (also known as fluvial flooding) and surface water flooding. Of all these sources London is most vulnerable to surface water flooding. Heavy rainfall can swiftly overwhelm the drainage network, leading to flooding of low-lying areas.  

During the 2007 floods, more than 1,000 homes, over 80 schools and parts of several hospitals were flooded in London despite London receiving only a third of the rainfall that affected other areas of the country. Climate change is projected to increase the frequency and intensity of heavy rainfall events, whilst London’s growth will mean that more people and assets will be at risk.  

It is estimated that a 1 in 50 year rainfall (or 2% annual chance) event today would flood 1 in 7 buildings in London, with insured damages running to tens of billions of pounds.  

Local authorities' role in flood risk management

Recently adopted legislation in the form of the Flood and Water Management Act 2010 and the Flood Risk Regulations 2009 place new responsibilities on local authorities in their role as Lead Local Flood Authorities (LLFAs), including the drawing up of local risk assessments, and approving sustainable drainage systems (known as SUDS).

In order to enable local authorities to meet these new duties, the government has provided extra funding through the Area Based Grant to each London authority. It is for authorities to identify what flood risks exist in their area, what interventions could help to mitigate those risks and to manage the funding that is available for these interventions.

In the first stage of this process Local Authorities have been required to submit Preliminary Flood Risk Assessments to the Environment Agency in June 2011.

Drain London

London Councils has been involved in the Drain London partnership since its inception, along with London’s 33 boroughs, the Environment Agency, Thames Water, Transport for London and the GLA. The partnership was set up to enable local authorities in the capital to work together to better understand surface water flood risk and build their capacity to manage their flooding risks. You can read more here.

Support for boroughs 

London Councils is working in partnership with the Environment Agency to support local authorities in meeting their new statutory duties as Lead Local Flood Authorities. This includes working with councillors to develop their involvement in flood risk management within each borough and also to support the lead members representing London on the Regional Flood and Coastal Committee (RFCC). You can read more about this support work here.