Policy information sourced from the Harrow and Wealdstone Area Action Plan

AAP9: Flood Risk and Sustainable Drainage

Major development proposals on nonallocated sites in identified flood risk areas will be required to undergo sequential and, where relevant, exception testing. With regard to the sequential test, the area of search will be confined to the Heart of Harrow area where the proposal involves the creation of more than 50 jobs, more than 50 net new homes, or contributes significantly to the regeneration of Wealdstone. With regard to the application of the exception test, a high priority will be accorded to the delivery of physical and social regeneration within Wealdstone district centre.

Proposals on allocated and non-allocated sites requiring a Flood Risk Assessment must demonstrate that the development is designed and laid out to be resistant, resilient and safe from all sources of flooding and there is a net flood risk reduction. Finished floor levels must be designed to be at least 300mm above the 1 in 100 flood level, including an allowance for climate change, and be fitted with flood resilience measures to 0.5m above finished floor level. Development that involves the formation of new basements, or the change of use of existing basements, must have regard to flood risk and ensure that this is specifically addressed through the Flood Risk Assessment. The installation of resilience measures to basements will be required. Proposals for the formation of new dwellings or additional habitable accommodation within basements will be refused.

Major development, and proposals for promoting a comprehensive change of use, will be required to:

  • Reduce the surface water run-off rate of the site to Greenfield run-off rates wherever feasible;
  • Utilise sustainable urban drainage systems (SUDS) unless there are practical reasons for not doing so;
  • Ensure adequate arrangements are in place to secure the long-term responsibility for the management and maintenance of on-site infrastructure;
  • Use appropriate measures to prevent water pollution; and
  • Where appropriate, demonstrate that the proposal would be resistant and resilient to flooding from all sources.

In selecting the sustainable measures to be used, preference should be given to those that reduce demand for mains water and which contribute to biodiversity and improving water quality.

Proposals that fail to reduce surface water run-off, and/or fail to make appropriate provision for flood risk mitigation or that would increase the risk of flooding or water pollution, will be refused.

In the event of feasibility being proven for the provision of source control measures within Kenton Recreation Ground, the Council will use funds raised through its Community Infrastructure Levy and other sources to implement the scheme.

For more information please see the Area Action Plan