PPS 15: Planning and Flood Risk
FLD 1: Defended Areas
8.4 The development of previously developed land protected by existing flood defences will generally be acceptable where the defences provide an appropriate standard of protection from flooding. However, even previously developed land within defended areas may be unsuitable for certain types of development. This is because flood defences, whilst reducing the probability of flooding, cannot eliminate it entirely and because flooding can have particularly serious consequences for the vulnerable in our society - children, older people and those with disabilities and others whose mobility is impaired.
8.5 Flood defences protect land against a specific height of floodwater (often referred to as 'the design flood') and a flood greater than this may overwhelm the defence and flood the defended area. Additionally, should a floodwall or embankment be breached, land, buildings and their occupants can be very vulnerable to the rapid inundation that can result.
8.6 Because of this, essential civil infrastructure such as hospitals, fire stations, emergency depots and ground based telecommunications equipment will be unacceptable in locations where access and uninterrupted operation in time of emergency cannot be guaranteed.
8.7 In addition planning permission will only be granted exceptionally for the development of schools and nurseries, care homes, sheltered housing or accommodation/facilities for other vulnerable groups in defended areas and a presumption against the extension of such facilities will operate in these areas.
8.8 Facilities such as storage sites for hazardous substances, fuel storage depots and sewage treatment works are a potential source of pollution if located within an area at risk from flooding. While it may be possible to permit their location in defended areas where it is demonstrated that an alternative lower risk location is not available, their approval will be conditional on the provision of pollution containment measures designed to prevent a pollution incident in the event of flooding.
8.9 Even when afforded a level of protection from flood defences, the development of green field sites and areas of open space 7 within a flood plain can increase flood risk. This is because adding to or intensifying the use of the developed area at risk increases the potential consequences of a flood event. The Department will therefore operate a presumption against the grant of planning permission in such circumstances to ensure that ad hoc proposals do not increase flood risk and/or lead to a need for new hard flood defences. Decisions on the future development of such sites will normally only be taken through the development plan process.
7 PPS 8 ‘Open Space, Sport and Outdoor Recreation’ advises that open space of public value does not fall within the definition of ‘brownfield / previously developed sites’.