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Flood Risk Assessment


Flood Risk Assessment

What are Flood Risk Assessments?

A Flood Risk Assessment (FRA) takes into account the risk and impact of flooding on the site, and considers how the development may affect flooding in the local area. It also provides recommendations as to how the risk of flooding to the development can be mitigated.

An FRA should demonstrate the site will be safe, both now and in the future, taking into account the effects of climate change and the vulnerability of the type of development proposed.

How does this affect my client?

The National Planning Policy Framework (NPPF) and Planning Practice Guidance (PPG) have been developed to provide specific support for architects, land surveyors and developers. Section 10 of the PPG highlights that ‘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, making it safe without increasing flood risk elsewhere.’

An FRA is an essential part of the site assessment and planning submission process and is usually a key requirement by the Local Planning Authority.

Architects and planning consultants must advise their client on any potential flood risk issues that could affect whether the development project could go ahead based on its location, site drainage conditions and LPA flood risk zone.

Understanding Local Authority Requirements

Planning conditions on Flood Risk Assessment vary across the country and are driven by the LPA’s own Flood Strategy, now produced in conjunction with their Lead Local Flood Authority (LLFA).

Architects and planning consultants must understand these differences, assess the site and are aware of the further investigations that may be necessary. They must assure LPAs that the development will meet strict tests or mitigates future flood risk.

We have developed a unique catalogue of planning authority Flood Risk Assessment requirements.


Get an Expert View on Flood Risk

We have many years experience in assessing flood risk and recommending next steps, as part of master planning and pre-application submissions.
We have a proven track record of delivering successful outcomes through our technical expertise.

Our flood risk assessment reports provide:

  • A professional opinion from expert flood risk consultants
  • Consultation with regulators and EA data analysis
  • Review of LPA Strategic Flood Risk Assessment
  • Review of historic flood levels
  • Clear flood mitigation and management options


Do I need a Flood Risk Assessment?

A Flood Risk Assessment is required for any planning application where the site of the proposed development is located within Flood Zones 2 or 3 as defined by the Environment Agency. Such sites are considered to be at risk of flooding and the Environment Agency and local planning authorities have the power to challenge planning applications that have not taken into account all of the flood risks involved.

A Flood Risk Assessment is also mandatory for sites of 1 hectare or greater in Flood Zone 1, and for smaller sites in an area within Flood Zone 1 which has critical drainage problems, as notified to the local planning authority by the Environment Agency. For further information on the relationship between Flood Zones and Flood Risk Assessments, see our news item Flood Zones Explained.

A Flood Risk Assessment should demonstrate how a proposed development will manage flood risk from all possible water sources to the site in question. Changes in flood risk to off-site locations as a consequence of development should also be considered with recommendations provided to avoid increasing such risk.

What are the Flood Risk Zones?

If you live in England, your site will be located in a Flood Zone as defined by the Environment Agency for planning purposes, but many will be located in Flood Zone 1 with a low probability of flooding. To find out what Flood Zone your site is located in, input your postcode into the Environment Agency Flood Map.

Why might a flood risk assessment be required?

  • Validating planning applications
  • Meeting planning conditions
  • For land and property purchase
  • For the sale or divestment of a site
  • Due diligence
  • Lending, mortgages, pension funds
  • Business risk assessment





How we can help our clients


Some examples of how our flood risk assessments have supported our clients planning submission requirements.

Flood Risk: Mixed Use Development
We were asked to assess the potential significance of flood risk to a mixed use (commercial and residential) development.
Coastal Flood Risk Assessment – Grimsby.
We were instructed to assess the nature and potential significance of coastal flood risk to land upon which a group of residential houses was proposed.
Flood Risk: Development Proposal on Former Farmland – Shropshire
We were asked to assess the potential significance of flood risk to land upon which a two house residential development was being proposed on a site formerly used as a battery hen farm.



We also run a regular series of webinars and can provide in-house seminars to ensure your team is up to speed on the latest requirements and support their CPD needs.