In addition to any requirement for a Flood Risk Assessment (FRA), the following information with regard to surface water drainage must be submitted:

Outline Planning Application

Any outline application for a development falling within the definition of ‘major’ shall be accompanied by a drainage strategy. Information to include:

• indicative sustainable drainage principles for the development
• topographical survey showing how water naturally flows on the site together with
• groundwater and land drainage flows
• proposed destination for surface water post-development
• ground investigation results for infiltration (if appropriate)
• existing and/or proposed watercourses
• existing and/or proposed surface water sewers and/or pumping stations
• surface water flows onto the site, flows from the site and flood risk to and from the site
• offsite works which may be required to provide surface water drainage or mitigate
• against flood risk
• sensitive receptors
• general maintenance principles

Full Planning Applications

In addition to details required for an Outline application (listed above) the following shall be provided:

• details of compliance with Defra non-statutory technical standards
• off-site works
• consents required
• flow paths through the development
• surface water storage volumes and locations
• sub-catchment areas
• treatment train components
• proposed landscaping and/or vegetative systems
• design calculations for:
  -greenfield run-off
  -brownfield run-off if appropriate (including reductions)
  -peak flow rates
  -surface water volumes
  -storage requirements
  -drain down times
  -multi-use areas
  -exceedance routes
  -temporary drainage during construction
  -climate change allowances
  -future development allowances
  -details of how the sustainable drainage system is to be maintained, and by whom, for the lifetime of the development