Flood Risk Policy in Royal Borough of Kensington and Chelsea
RBKC's 2024 Local Plan splits flood risk into two policies, extends FRA requirements to all basement development, and bans sleeping accommodation below ground in Flood Zone 3.
In July 2024, the Royal Borough of Kensington and Chelsea (RBKC) adopted a new Local Plan which has superseded the previous Local Plan (2019).
Within the 2019 Local Plan, Policy CE2 Flooding was the sole policy that focused on reducing the impacts of flood risk, and the implementation of SuDS across the Borough. Now, within the 2024 Local Plan, the flood risk and SuDS requirements have been split across two policies, into Policy GB11: Flood Risk, and Policy GB12: Sustainable Drainage.
When is a Flood Risk Assessment Required?
Previously under Policy CE2, a site-specific Flood Risk Assessment was required for all development in Flood Zones 2 and 3, for sites in Critical Drainage Areas, and for all sites greater than one hectare. Policy GB12 of the 2024 Local Plan reiterates this but extends the requirement, and now “all basement development should submit a Flood Risk Assessment.”
Sleeping Accommodation
Previously, Policy CE2 stated that the Council will resist “vulnerable development”, including self-contained basement dwellings, in Flood Risk Zone 3 and Critical Drainage Areas. Policy GB11 of the 2024 Local Plan states that in addition to the above, “no sleeping accommodation will be permitted below ground floor level in Flood Zone 3.”
Development Within Proximity of the River Thames
The 16-meter setback from flood defences is now formalised in the 2024 Local Plan with GB11 stating “New development adjacent to the River Thames and Chelsea Creek must be set back by 16m from the Thames flood defence, including tie rods and support structures, to enable the sustainable and cost-effective upgrade of flood defences in line with the requirements of the Thames Estuary 2100 Plan.”
Sustainable Drainage Systems (SuDS)
Within GB12, the 50% reduction requirement for minor development has been relaxed, with the policy now stating “Householder applications must reduce the rate of runoff from the site in a way that is proportionate to the scale of development and reflects the site constraints.” This removes the need to provide 50% reduction in runoff rates for the whole site.
However, the 2024 Local Plan still reiterates that “All development, regardless of size, should ensure that there is a net reduction in flows to the combined sewer network.”