FLOOD RISK ASSESSMENT
Development and Flood Risk

Across England and Wales there are an estimated 5 million people living in 2 million properties in areas at risk of flooding. The devastating events of Easter 1998, Winter 2000 and June 2007 showed the misery, loss and damage that can accompany a flood and the impact of climate change is set to make flooding a more common occurrence. To ensure that people are not unnecessarily placed at risk of flooding, the Government published Planning Policy Statement 25, Development and Flood Risk, (PPS25) so that flood risk is taken into account at all stages of the planning process. PPS25 requires that any proposed new development in an area at risk of flooding must be accompanied by a Flood Risk Assessment (FRA). The FRA must demonstrate that there are no reasonably available alternative locations that could be developed in areas at lower risk of flooding (the Sequential Test) and that both the development and its occupants will be safe, and will not increase the flood risk to others (the Exception Test).

Where a FRA is required, the failure to submit a FRA with the Planning Application can be grounds for refusal in itself. However, it should be noted that a FRA will not necessarily support the development of a site.

"I do not know much about gods; but I think that the river
Is a strong brown god - sullen, untamed and intractable,
Patient to some degree, at first recognised as a frontier;
Useful, untrustworthy, as a conveyor of commerce;
Then only a problem confronting the bulder of bridges.
The problem once solved, the brown god is almost forgotten
By the dwellers in the cities - ever, however, implacable,
Keeping his seasons and rages, destroyer, reminder
Of what men choose to forget. Un-honoured, unpropitiated
By worshippers of the machine, but waiting, watching and waiting".

The opening of "The Dry Salvages" 1941
One of the four Quartets by T.S. Eliot

What is Flood Risk Assessment?

Whilst the Environment Agency publish indicative flood maps on their web site, Click here to view the flood maps, these maps should be treated with caution as they are drawn from a variety of sources and are often based on low resolution topographic data. However, these maps do provide a useful starting point in highlighting flood risk to a potential new development.
Flooding can arise from a variety of sources including from rivers, the sea, the land, groundwater and sewers. Flooding mechanisms are equally varied; the capacity of a watercourse, culvert or sewer can be exceeded by a flood flow or an existing defence breached or overtopped. PPS25 provides guidance on what is considered an acceptable risk for new development based on the vulnerability of its use together with the source and mechanism of flooding. Assessing the flood risk to a particular development, and the impact it may have on the flood risk to others, can therefore be a complex and time consuming task.
Bureau Veritas’ team of qualified Engineers and Hydrologists have extensive experience in assessing flood risk. The assessment can be based on the interpretation of flood data provided by the Environment Agency (where it exists) through to the construction of detailed 1-dimensional (1D) and 2-dimensional (2D) hydraulic models where no data is available. Advice is also given on measures to manage and mitigate flood risk, both to the development and to others who may be affected by the development. For larger scale developments, particular attention has to be paid to addressing the impact of increased runoff through the incorporation of sustainable drainage measures (SuDS) in the surface water system.
Bureau Veritas can support their Clients with pre-application advice on the requirement to provide an FRA, through to providing expert evidence on flooding and drainage issues at Planning Inquiries. We have completed FRA’s for single dwellings through to major urban extensions as well as for large commercial and mixed-use developments.
Bureau Veritas is also routinely retained by Local Authorities to provide advice on existing flooding problems and have been responsible for the delivery of a number of flood alleviation schemes.
Where the scale or nature of development falls within the scope of the Town and Country Planning (Environmental Impact Assessment) (England and Wales) Regulations 1999, the impact on the water environment is often a key issue that must be addressed. The Development and Flood Risk team has considerable experience in completing these assessments and contributing to the preparation of the Environmental Statement.

What are the key benefits?

- Preliminary advice on development potential with respect to flood risk
- Identify, manage and mitigate flood risk
- Maximise development potential of the site
- Support at every stage of the planning process
- A well qualified, experienced team comfortable working within a multi-disciplinary environment