Flood Risk Assessment (FRA),
Residential development site
Morton-Roberts produced a Flood Risk Assessment for a 3ha greenfield site close to the River Frome in Somerset which the Client wanted to develop for
residential purposes. The study examined the risk of flooding from various sources including fluvial (river), surface water, ground water, sewers as well
as due to infrastructure failure.
Preliminary assessment of on-site surface water drainage (SUDS)
The study also investigated the possible SUDS techniques which would be appropriate at the site although the choice was restricted due to the predominant
soil type, mudstone, which was unlikely to be suitable for infiltration methods. The report suggested that rainwater harvesting systems should
be considered to attenuate the flow from individual roofs with permeable pavements (non-infiltrating type) to attenuate the run-off from drives, etc. The
study also suggested an attenuation pond as a site control measure to limit the post development surface water run-off to the greenfield value. The total
volume of storage required was estimated at 1070m3.
Flood zone 1
The study concluded that the site was unlikely to flood due to river flooding for a 1 in 1,000 year return period flood and so was located within flood
zone 1. The study also identified a low possibility of surface water flooding and recommended that this be considered again at the detail design stage.
Further details of Flood Risk Assessments
For further details of our services in the area of Flood Risk Assessments and Flood Consequence Assessments please see the following pages:
Flood Risk Assessments (for use in England).
Flood Consequence Assessments
(for use in Wales).