Building on the flood plain

Building on the flood plain

In a perfect world no one would want to be building within a fluvial flood plain and tidal flood zone, but with such competition for land, it is something that cannot be avoided all the time. Record breaking rainfall has seen flooding sweep across the UK, and yet according to the Committee on Climate Change (CCC), Great Britain is building ‘faster in the flood plain than anywhere else’.[6]

Towards the end of 2015, the UK faced severe storms. After the extreme winter floods of 2013-2014, many thought we would be better prepared. National media question whether the construction plans on flood plains have weakened Britain’s flood defences and whether they are the main cause of the devastating floods occurred over the last few years.[3], [4], [6], [7]

Local authorities are under growing pressure to find sites for housing, so the need to build new homes – and quickly – is critical.[1]  Flood plain land is some of the cheapest available to developers.[1] A flood plain is an area of flat land near a river, stream, lake or other open waterway that is subject to flooding when there is significant rainfall.[2] A flood zone is a commonly used term in floodplain management. Flood zones are areas identified by the Environment Agency (EA) and refer to the probability of river and sea flooding, ignoring the presence of defences.[8] Flood zones are divided into Flood Zone 1 (Low Probability flooding events), Flood Zone 2 (Medium probability), Flood Zone 3a (High Probability) and Flood Zone 3b (the Functional Floodplain).[8] Everyone lives in a flood zone, it is just a question of whether you live in a very low, low, moderate, or high risk area.

UK building boom- a growing trend of planning permissions being passed

Despite warnings from the Environment Agency and the Committee on Climate Change (CCC) between 2001 and 2011, 200,000 new houses were built on the flood plain[3] whilst at present there are almost 500,000 homes that have been given planning permission and are waiting to be built on the flood plain.[7]

In 2011 the coalition government relaxed planning rules. Since then local planning authorities no longer had to report cases where they ignored EA advice and it has also become easier for them to approve planning applications in high-risk areas.[7] Many homes in at risk-areas are being built with the EA’s approval because they are behind existing flood defences which are considered to provide adequate protection from flooding. Other homes may be being built without the EA’s oversight because they are in small developments of 10 units or fewer.[6]

Some interesting numbers

According to the Financial Times[4], Great Britain is building nearly 10,000 new houses a year on flood plains. Figures obtained by The Telegraph[6] reveal that new houses are being built in England’s highest-risk flood areas at almost twice the rate of housing outside flood plains. Housing stock in areas where flooding is likely at least once every 30 years has grown at a rate of 1.2 % annually since 2011 whereas housing outside of flood plains (in areas with less than a 1-in-1,000-year flood) has increased at a rate of 0.7% per year over the same period.

Current trends suggest that up to 20,000 new houses are scheduled for development this year in areas at risk from flooding, with about 4,500 of these to be medium or high risk areas, where flooding is expected at least once every 100 years.[6]

So is building in a flood plain still possible?

Within the fluvial flood plain and tidal flood zone the risks of flooding should be reduced by the incorporation of appropriate flood protection measures in the design and construction of buildings. Structures are generally required to be elevated above the base flood elevation and an engineering evaluation is required to determine there will be no adverse impact to upstream properties.

A big percentage of council-owned land falls within Flood Zone 2 and 3. Developing and building new homes on flood plains is a necessity and yes, it is possible. The key is to make the quality of planning applications better, in flood risk terms. Developers planning to build in a flood plain should be familiar with the framework and accompanying guidance and they should undertake compliant flood risk assessments to demonstrate building on flood plain is acceptable. These assessments, and any mitigation measures must also be made available to insurers to ensure that householders are able to obtain household insurance. Good planning for developments falling within Flood Zone 2 and 3 is essential to reduce the impacts of flooding. Any future development within areas where flood risk exists will need to be designed to withstand the possibility of flooding, and be able to manage the effects of flooding to ensure that it is safe over the proposed lifetime of the development.[9]

Flood Re

‘Flood re-insurance scheme’-known as Flood Re-is a new way to help people who live in flood risk areas get affordable home insurance. The scheme is a collaboration between the insurance industry and the Government and will launch on April 4th 2016.[10], [11]

Flood Re will be in place for 25 years and is designed to: 1) enable high flood risk households to obtain affordable flood insurance; 2) promote the availability and choice of insurers and insurance brokers for clients; and 3) allow time for the Government, local authorities and insurers to become better prepared for the possibility of a flood.[12] Flood Re will take the flood risk element of home insurance from an insurer in return for a premium based on the property’s council tax band. It is estimated that, over time, around 350,000 homes could benefit from Flood Re.[12] Properties built after 2009 will remain exempt in order to discourage the development of properties on flood plains.[11]

How can Groundsure help?

A flood report is essential before deciding to go-ahead with any type of property transaction or development site purchase.

For residential transactions a Groundsure Flood report should be purchased. This report identifies the flood risks at the property from river, coastal, surface water and groundwater as well as giving an insurability rating and a statement on the possibility of the property being ceded into Flood Re.

For commercial property transactions or development sites a Groundsure Floodview Report would be the most suitable. This is a preliminary flood risk assessment report that can help buyers and developers understand the risks and opportunities before purchasing a property or making an application to build on a floodplain.

The Groundsure Floodview contains high quality data on different types of flooding with a fully interpreted risk assessment and includes an opinion on the likely availability of insurance for a flood-risk property. In addition, the report identifies whether there are any EA Zone 2 or Zone 3 flood plains within a 250m search radius and highlights the presence of any flood defences within this radius. It also identifies the need for a NPPF Flood Risk Assessment (FRA) to be carried out for developments within Flood Zones. A FRA enables the developer to identify the measures (if any) that are necessary to make the development safer and ensure it will not increase the risk elsewhere, to satisfy the Exception Test.

If we are going to build on flood plains, we must ensure houses are adequately protected. A developer is advised to undertake a flood risk assessment and consult the Environment Agency, the local authority or both on any proposed developments at a higher risk from flooding before making a decision.


[1] Thomas, S., 2015. If We’re going to build on Floodplains, we must ensure homes are adequately protected. The Huffington Post, [online] Available at: [Accessed 14 February 2016]. [2] CCEO, n.d. Construction in the Floodplain. [online] Available at: [Accessed 14 February 2016].

[3] Wills, T., 2014. The scandal of 200,000 homes built on flood plains. ampp3d from Mirror, [online] Available at: [Accessed 14 February 2016].

[4] Allen K. and Bounds A., 2015. UK building 10,000 homes a year on floodplains. Financial Times, [online] Available at: [Accessed 14 February 2016].

[5] Heighton, L., 2015. £200 million flagship scheme could see new homes built on floodplains. The Telegraph, [online] Available at: [Accessed 14 February 2016].

[6] Gosden E., 2015. Housebuilding rates higher on flood plains as UK ‘stores up problems for future’. The Telegraph, [online] Available at: [Accessed 14 February 2016].

[7] Brickhunter, 2016. Floods vs Construction. Is the UK building boom responsible for the flooding in 2015? Brickhunter, [online] Available at: [Accessed 17 February 2016].–BLOG

[8] Department for Communities & Local Government, 2014. Flood Zone and Flood Risk Tables, [online]. Available at: [Accessed 18 February 2016].

[9] Southampton City Council, n.d. Development and flood risk, [online]. Available at: [Accessed 18 February 2016].

[10] ABI, 2014. Flood Re – a customer guide. [online]. Available at: [Accessed 8 March 2016].

[11] Cristie, S., 2015. Flood Re: Government insurance scheme launch confirmed for 2016. The Telegraph, [online] Available at: [Accessed 8 March 2016].

[12] Flood Re, n.d. [online] Available at: [Accessed 8 March 2016].

This article was submitted to be published by Groundsure as part of their advertising agreement with Today’s Conveyancer. The views expressed in this article are those of the submitter and not those of Today’s Conveyancer.

Clelia Chelmi, Groundsure

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