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Adapting to flood risk in a changing climate

Is current policy helping to address the expected increase in future flood risk?

Last winter’s storms and floods illustrated the costs of a lack of resilience to extreme weather. Many thousands of people were forced to leave their homes and the country’s transport and energy infrastructure suffered significant disruption. Evidence suggests extreme weather events may become more frequent and severe in the future, along with more gradual changes in average temperature, patterns of rainfall and on-going sea level rise.  There is a clear need for the Government and wider society to be actively considering how to increase the nation’s resilience to the very real risk of increased flooding and more extreme weather in the future.

There are a number of issues that need to be tackled. Firstly, we have concerns with the amount of investment going into flood risk management (see our blog on this). Despite the injection of £270 million to repair the damage done last winter, three-quarters of flood defence structures are not being maintained at an optimal level. Hundreds of new flood protection projects won’t be delivered until 2019 at the earliest and future investment is set to flatline, in real terms, to the end of the decade.  Previous advice from the Environment Agency suggests that will lead to a near doubling in the number of properties in England at significant flood risk, from 490,000 today to more than 800,000 by the mid-2030s.  And that’s before new housebuilding is factored in.

Secondly, we are putting up buildings at a faster rate in areas of flood risk than elsewhere. In Sedgemoor District in the Somerset Levels, for instance, 900 new homes have been built this century in areas with a significant chance of flooding.  Our analysis identified that across England around 40,000 new properties were built in areas of significant risk between 2001 and 2011. Even if these new properties are being designed to be resilient, continuing to develop on the floodplain increases our reliance on flood defences.  As we saw last winter, defences can be overtopped, or fail, in storm conditions, with potentially catastrophic consequences.

Thirdly, greenspaces in our towns and cities continue to be concreted over – we found that the proportion of urban front gardens with impermeable surfaces jumped from 28% in 2001 to 48% in 2011. As a result, rainwater is running-off straight into our sewer system, which is already struggling to cope with 50% of the national network at or beyond capacity.  Ofwat estimate that a combination of climate change and urban infilling will increase sewer flooding by around 30% over the next few decades. There are ways to manage local flood risk: sustainable drainage systems (known as SUDS) can be installed that mimic greenspace and ‘permeable paving’ purposefully allows rainwater to infiltrate.  However, we found low uptake of these adaptation measures to date, for example only 10% of all paving sales were permeable in 2013.

The Government is certainly aware of the need to adapt to a changing climate. A National Adaptation Programme (NAP) was published in 2013 that contains a long list of policy objectives and detailed actions.  Having such a programme in place is to be welcomed.  However, the test will be whether the NAP is actually making a difference to addressing the risks from a changing climate, particularly from increased flooding. The ASC will be reporting to Parliament in the summer of 2015 with our assessment of the NAP and where we think more action is needed.

This blog is an extract from an article written for the RSPB by ASC analyst, Dave Thompson.

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