A Flood Risk Assessment is normally required for any planning application in which the location of the development falls in Flood Zones 2 or 3 as defined by the Environment Agency. We often get asked by our clients what the reason is behind why Flood Zone 1 is required by the Local Council/Environment Agency.
Flood Zone 1 is an area with a lower than 0.1 percent chance of flooding. Flood Zone 1 sites with at least 1 hectare are required to undergo an Flood Risk Assessment. There are also sites which have less than one hectare in Flood Zone 1 which need an Flood Risk Assessment, including sites which have significant drainage issues and have been reported to the local authority for planning by the Environment Agency. CDAs are the areas within Flood Zone 1 that have been recognized by the Environment Agency as susceptible to flooding. This can lead to the runoff of water from downstream. Flood Risk Assessments aren’t the only place where flooding problems may occur.
You might also have to complete an Flood Risk Assessment in Flood Zone 1 If your building is susceptible to other sources of flooding (for instance, surface water drains or reservoirs) or even a shift in use in development type to a more vulnerable class like commercial or residential, could also result in a Flood Risk Assessment being required.
What happens if my site is completely or in part within a Flood Zone 2 or 3?
A Flood Risk Assessment that is tailored to sites within Flood Zone 1 won’t be suitable for sites that are in Flood Zone 2 or 3. Flood model data from the Environment Agency and Council will be requested when the Site is situated in an area that is more hazardous to flood. Even if a small portion of the Site redline boundary is in Flood Zone 2 or 3, or if the proposed development is in the lower flood zone (Flood Zone 1), this will apply.
How can I determine which Flood Zone my Site is in?
If your Site is located in England, it will be situated in a Flood Zone 1-3 as defined by the Environment Agency’s Flood map for planning. Find out which Flood Zone your site is located inby entering your postcode on the Environment Agency Flood Map to discover.
Natural Resources Wales (NRW), has its own Flood Zones if your Site is located in Wales. The maps display three development advisory zones (A-B C, A and C) that could be linked to various plans. Zones B and A are areas of generally low risk. Zone C is the extreme floodline and can be further subdivided into C1 as well as C2.
Zone C1: defined as “areas of the floodplain which are developed and served by significant infrastructure, including flood defences.
Zone C2 is defined as an “area of floodplains that do not have significant infrastructure for flood defence.”
In essence, if the Site is located in the Flood Zone C1 or C2 it is the equivalent to the EA’s Flood Zone 3.
The Scottish Environmental Protection Agency (SEPA) is situated in Scotland assesses flood risk in relation to the risk of flooding caused by surface water, rivers, as well as coastal flooding. These zones are divided as high, medium, and low-risk zones.
Where can I purchase an Flood Risk Assessment?
This Flood Risk Assessment is available for all sites in the Flood Zone 1. The assessment covers flooding from all sources in a detailed assessment of any flood hazards that may be in the area.
