Policy information sourced from Lambeth Local Plan 2020-2035

EN5: Flood risk

The council will seek to minimise the impact of flooding in the borough through:

  • applying a sequential, risk-based approach to the location of development to avoid, where possible, flood risk to people and property and manage any residual risk, taking account of the impacts of climate change over the lifetime of the development;
  • steering development towards areas of lowest flood risk, both across Lambeth and within the development site boundary, through the application of the Sequential Test in accordance with the NPPF, taking the vulnerability of the proposed uses into account, as set out in the Lambeth Strategic Flood Risk Assessment (SFRA); 
  • ensuring development does not increase flood risk and where possible reduces flood risk from all sources of flooding;
  • permitting appropriate development in Flood Zones 1, 2, 3a and 3b subject to meeting the criteria set out in Annex 4; and
  • taking account of the flood risk management measures identified by the Thames Estuary 2100 Plan.

All development in Flood Zones 2, 3a and 3b defined in the SFRA, or identified as at risk of flooding from other sources, should contribute positively to actively reducing flood risk through avoidance, reduction, management and mitigation.

A Flood Risk Assessment (FRA) will be required for major development proposals within Flood Zone 1, all development within Flood Zones 2, 3a and 3b, or where the development may be subject to other sources of flooding. The FRA should be proportionate with the degree of flood risk posed to and by the proposed development; consider the impact of climate change on flood risk to and from the development using the latest government guidance; and take account of the advice and recommendations set out in the SFRA, Surface Water Management Plan (SWMP) and Local Flood Risk Management Strategy (LFRMS).

FRAs must consider the risks of both on and off-site flooding to and from the development for all sources of flooding including fluvial, tidal, surface water run-off, groundwater, ordinary watercourse, sewer (separate or combined) and reservoir.

For all developments, it must be demonstrated that the development will be safe (for its lifetime), and where required, it will reduce fluvial, tidal, surface water run-off and groundwater flood risk and manage residual risks through appropriate flood risk measures, including the use of sustainable drainage systems (SuDS) in accordance with Local Plan policy EN6. Measures to mitigate flooding from sewers should be discussed with Thames Water Utilities Ltd. and be included in development proposals for which this is a risk.

The use of basement space for bedrooms and non-residential uses where flooding could threaten the safety of people will not be permitted in areas susceptible to flooding (including but not limited to areas within current modelled breach flood extent and surface water modelling). The use of basement space for all other residential and non-residential uses must adopt resilient design techniques and be flood resilient. Basement proposals should not increase flood risk elsewhere. See also Local Plan policy Q27.

For developments adjacent to the River Thames and River Graveney, maintenance, remediation and improvements to the flood defence walls will be required where necessary. Developments adjacent to defences and culverts should demonstrate that their development will not undermine the structural integrity or detrimentally impact upon its intended operation and future maintenance.

For more information please see the Local Plan