Policy information sourced from the Bexley Local Plan

DP32: Flood risk management

Planning for flood risk

  1. In areas at risk of flooding, as identified in the Bexley Strategic Flood Risk Assessment (SFRA), development proposals must:
    • be within a Sustainable Development Location, designated industrial location or the Thamesmead and Abbey Wood Opportunity Area if the site is within Flood Zones 2 and 3a, except for householder development above defined flood levels, and the development type is acceptable within the flood zone, as only these locations have passed the Local Plan sequential test;
    • apply the exception test, where required, to sites within Flood Zones 2 and 3a that have met the requirements of part 1a;
    • comply with the guidance and recommendations set out in the Bexley SFRA Level 1 and Level 2;
    • apply the sequential approach advocated in the NPPF to all sources of flooding, not just tidal and fluvial;
    • be used as an opportunity to reduce the causes and impact of flooding;
    • make as much use as possible of natural flood management techniques as part of an integrated approach to flood risk management); and,
    • provide floodplain storage capacity as close to the development as possible, where the proposed development will reduce this capacity.

Tidal and fluvial flooding

  1. Habitable rooms in residential development within the fluvial flood zones, should be set 300mm above the predicted 1 in 100 year plus climate change peak flood water level, and within the tidal flood zones, should be set at the predicted 1 in 200 year annual probability.
  2. Development in areas designated as Functional Floodplain (as identified in the SFRA Level 1 and the Policies Map) will not be permitted outside of water-compatible development, as defined in the NPPF.
  3. All proposals for development in Flood Zones 2 and 3, and all proposals on sites of 0.25 hectares or larger regardless of what flood zone the site is in, must include a site-specific flood risk assessment (FRA), including a drainage impact assessment.
  4. New developments in riverside locations are required to help reduce flood risk now and into the future.
  5. Development proposals located within 100 metres of the Thames tidal flood defences should demonstrate consideration of and act on the recommendations of the TE2100 Plan and be designed in such a way as to easily facilitate the raising and re-engineering of the tidal flood defences.
  6. Basements will not be permitted in Flood Zones 2 or 3 

Surface water, groundwater and sewer flooding

  1. Development must not increase flood risk on-site or off-site, and exceedance flows must be considered and appropriately managed.
  2. All basement developments should include, within their proposal, protection to the property by installing, for example, a non-return valve or other suitable device to avoid the risk of backflow at a later date, on the assumption that the sewerage network may surcharge to ground level during storm conditions

Safe refuge, access and egress in, to and from development

  1. New developments below the predicted flood water level should include a detailed evacuation plan that clearly outlines how people can easily leave to safety or move upwards from the lower floors to safety.
  2. Site design in floodplains must facilitate safe escape, access and egress. Only in exceptional circumstances where this cannot be demonstrated should the emergency plan be to reside in situ and escape upwards in a building.
  3. All development that is intended to be occupied below the predicted flood water level must provide internal safe refuge above the design flood level

For more information please see the Bexley Local Plan