What is a Flood Risk Assessment?

A flood risk assessment (FRA) explores the risk of flooding from all sources of flooding, identifies

flood mitigation measures and provides advice and guidance on necessary actions which should be taken before and during a flood.

Why is a Flood Risk Assessment needed?

If you are applying for planning permission, you may need to carry out a flood risk assessment for your proposed development.

For instance, under the National Planning Policy Framework (NPPF) a Flood Risk Assessment (FRA) is required in support of a planning application where:

• the site comprises 1ha or above and is located within in Flood Zone 1
• the site is located in Flood Zone 2 or Flood Zone 3
• the site is located in a designated critical drainage area (as notified to the local planning authority by the Environment Agency

The flood zone classifications are based on the maps provided by the Environment Agency and are based on flood outlines associated with fluvial, tidal and coastal risk.

The FRA must consider the risk of flooding from these sources and all other sources (including ground water, surface water, canals, reservoirs and sewers), and demonstrate how any risk to the site and surrounding areas can be appropriately managed.

Local and national planning policies encourage development in areas at low risk of flooding but it is not mandatory. Where development is permitted in areas at medium or high risk of flooding, appropriate mitigation measures should be incorporated into the design.

The scale and level of detail included in the FSA is dependent on the flood risk and the vulnerability classification of the proposed development. In some cases, a simple FSA would be sufficient, and in others more detailed 1d or 1d/2d hydraulic modelling of watercourses may be required.

Particular consideration must be given to the sustainable management of surface water runoff, with the FSA demonstrating how there will be no increase in peak rates of surface water runoff from the redeveloped site (when compared with the existing situation) through the use of Sustainable Drainage Systems (SuDS).

Your Flood Risk Assessment during planning

Your planning application may be refused by your local planning authority if you haven’t included a FRA or if it isn’t satisfactory.

Base Energy has experienced assessors who undertake Flood Risk Assessments (England) and Flood Consequence Assessments (Wales) for sites in all flood zones.

Our Flood Risk Assessments are carried out in accordance with the National Planning Policy Framework and our Flood Consequence Assessments (FCA) comply with Technical Advice Note 15 – Development and Flood Risk. These assessments also comply with local planning policy as required.

Do you want to discuss a Flood Risk Assessment with one of our specialist assessors? Please call us on 020 3286 2016 or email us info@baseenergy.co.uk and we will get back to you within the same working day.

Useful links

• https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/6000/2115548.pdf
• https://www.gov.uk/guidance/flood-risk-assessment-for-planning-applications
• https://flood-map-for-planning.service.gov.uk/