Flood Risk Assessments

  • Fluvial or River Flooding
  • Tidal or Coastal Flooding
  • Surface Water Flooding
  • Sustainable Drainage Design

We are able to provide site specific ‘Flood Risk Assessments’ (FRAs) to accompany planning applications for both small domestic residential projects and larger commercial developments. In many cases the requirement to produce a flood risk assessment is triggered by the site’s location, possibly within the Environment Agency’s indicative flood plain, while in others this may have been requested as a means of documenting the absence of any additional risk associated with increased surface water run-off. All planning applications involving a site which exceeds 1 hectare must be accompanied by an FRA.

There are three main levels of FRA these are:

  • Level 1 Screening Study – predominantly desk based
  • Level 2 Scoping Study – a more detailed assessment supported by survey data and/or licensed information
  • Level 3 Detailed Study – likely to require site specific modelling

The type of assessment required for any given development will depend on a number of factors, the source of flooding and the severity of risk, the sensitivity of the proposed development and the availability of existing data on which to base the risk assessment.

Our Flood Risk Assessments are undertaken in accordance with the requirements of the new National Planning Policy Framework (March 2012), and the Practice Guide which accompanied the previous guidance ‘Planning Policy Statement 25 (PPS 25) – “Development & Flood Risk”. While this guide has been replaced, the associated Practice Guide remains the most detailed framework for the assessment of both external and internal sources of flood risk.  Flood Risk Standing Advice for England can be found on the Environment Agency website.

When preparing Flood Risk Assessment reports, we consider the following –

  • The potential source of flood risk
  • The most likely routes of such flooding
  • Likelihood of significant flood ‘hazard’
  • The most suitable finished floor levels
  • Safe routes of emergency access and egress
  • Additional areas of impermeable hard standing might result in increased rates of surface water run-off
  • Suitable and sustainable surface water management solutions
  • Adverse impact on any nearby watercourses or existing flood defences