Policy information sourced from the Kensington and Chelsea Local Plan

CE2 Flooding

The Council will require development to address and reduce flood risk and its impacts.

To deliver this the Council will:

Flood Risk

  • resist vulnerable development, including self-contained basement dwellings, in Flood Risk Zone 3 and Critical Drainage Areas as defined in the Strategic Flood Risk Assessment and the Surface Water Management Plan;
  • require a site-specific Flood Risk Assessment, including an ‘Exception Test’ for all development in Flood Risk Zone 2 and 3 as defined in the Strategic Flood Risk Assessment, for sites in Critical Drainage Areas and for all sites greater than one hectare;
  • where required undertake the ‘Sequential Test’ for planning applications within Flood Risk Zones 2 and 3, and for sites in Critical Drainage Areas;
  • require development at risk from flooding in Flood Risk Zones 2 and 3, in Critical Drainage Areas, or sites greater than 1ha to incorporate suitable flood risk measures to account for site conditions in accordance with Building Regulations, existing guidance and the recommendations of the site-specific Flood Risk Assessment, the Strategic Flood Risk Assessment and the Local Flood Risk Management Strategy. These measures should:
    • address all flood depths for the 1 in 100 year storm event plus climate change to ensure the development will remain safe during a flood event throughout its lifetime;
    • take into account access, egress and emergency exit routes;
    • ensure buildings remain safe for occupants in case of flooding, and are protected from sewer flooding through the installation of a suitable pumped device when the new development includes floors below the level of the sewer;
    • apply where required the measures and actions included in the Local Flood Risk Management Strategy Action Plan;
  • require that flood risk measures and flood risk assets are protected and maintained to remain operational and provide adequate protection for the lifetime of development;
  • require development adjacent to the Thames to be set back from the Thames flood defence to enable the sustainable and cost effective upgrade of flood defences and to implement any other recommendations of the Thames Estuary 2100 plan (TE2100).

Surface Water Run-off and Sustainable Drainage Systems (SuDS)

  • require major development to achieve greenfield run-off rates and minor development to achieve a reduction of 50% of existing rates, ensuring that surface water run-off is managed as close to its source as possible, through:
    • the increase of permeable surfaces;
    • recognising opportunities for SuDS to provide other environmental benefits;
    • factoring all flows into the sewer system (including swimming pools discharges, groundwater or other flows) in the calculations of greenfield run-off rates;
  • require SuDS to have regard to DEFRA non-statutory SuDS standards and local guidance to ensure SuDS are adequately designed, built and maintained for the lifetime of development;
  • resist impermeable surfaces in gardens and landscaped areas;
  • encourage the retrofitting of SuDS in buildings even if the development will not have drainage implications.

Water Infrastructure Projects

  • support the Thames Tideway Tunnel in principle;
  • support the provision of water and sewage infrastructure which will lead to a substantial and long-term reduction of local flooding, providing the need outweighs any adverse effects during construction and operation and appropriate mitigation measures are in place.

For more information please see the Kensington and Chelsea Local Plan