The Risk Of Flooding

A spate of major floods across the UK, warnings that global warming will lead to more frequent heavy rainfall events and increased risks of flooding have put the topic back at the top of the pile for planners.

A report from the Committee on Climate Change (CCC) in June 2015 (see reference box on p21) warned that not enough progress is being made in managing vulnerability to flooding, noting that new houses are currently being built in England's high-risk flood areas at almost twice the rate of areas at low or no risk of flooding. In its report, the CCC notes that the rate of residential development in areas with a 'high likelihood of flooding' (1 in 30 years or greater) has been on the increase for the period from 2011 to 2014, averaging 1.2% a year. In contrast, housing in Flood Zone 1 areas (see box on p19) averaged only 0.7% a year over the same period. Lord Krebs, head of the CCC's adaptation sub-committee, recently warned that if these trends continue, 'we are storing up problems for the future because flooding is going to get more frequent' (The Telegraph, 29 December 2015).

Recent floods such as those caused by Storms Desmond and Eva in December 2015 have hammered home (quite literally) how disruptive and costly flooding can be. There is increasing political recognition of the need for robust flood defences, with the Chancellor announcing an increase in flood defence and resilience funding of £700m by 2020-21 (funded by a 0.5% increase in the standard rate of insurance premium tax) in the 2016 Spring Budget, as well as an additional £130m to help repair the damage caused by the December 2015 floods.

As well as flood protection and mitigation measures, planning policy also has an important role to play in preventing development in unsuitable areas, and ensuring that developments are designed to robustly protect against future flood risks.

National policy

National planning policy aims to prevent inappropriate development in areas of flood risk, and is primarily set out in the National Planning Policy Framework (NPPF), supported by the Technical Guidance to the National Planning Policy Framework (Technical Guidance) and the National Planning Policy Guidance (NPPG).

Local planning authorities (LPAs) are required to adopt 'proactive strategies to mitigate and adapt to climate change', including taking full account of flood risk (NPPF para 94). Inappropriate development in areas at risk of flooding should be avoided by directing development away from areas at highest risk, but where development is necessary, it should be made safe without increasing flood risk elsewhere (Department of Communities and Local Government, see reference box on p21).

'Areas at risk of flooding' are defined in the Technical Guidance as:

land within Flood Zones 2 and 3 (see box on p19); or land within Flood Zone 1 which has critical drainage problems and which has been notified to the local planning authority by the Environment Agency. To assist LPAs in identifying and preventing inappropriate development, the NPPF requires that local plans are supported by a strategic flood risk assessment, and should contain policies to manage flood risk from all sources. Such policies should be developed in consultation with relevant flood risk management bodies, primarily the Environment Agency (para 100, NPPF).

Strategic flood risk assessments assess the risk to an area from flooding from all sources, now and in the future, taking account of the impacts of climate change. They also assess the impact that land use changes and development in the area will have on flood risk. LPAs should apply a sequential, risk-based approach to the location of development, both in allocating land within their local plans and when considering individual planning applications...