In our July 2008 Inform we discussed the new Practice Guide to PPS25 issued to offer guidance on how to implement the PPS25 development and flood risk policies. This new consultation document on amendments to the PPS25 has been issued to propose clarification to some of these existing development and flood risk policies.
The amendments are in Annex D to the PPS25 in relation to the definition of Flood Zone 3b – "the Functional Floodplain" and Flood Risk Vulnerability Classification.
The Functional Floodplain is defined as comprising land where water has to flow or be stored in times of flood and strategic flood risk assessments should identify this Flood Zone (land which would flood with an annual probability of 1 in 20 (5%) or greater in any year or is designed to flood in an extreme (0.1%) flood, or at another probability to be agreed between the local planning authority and the environment agency). Although this definition provided flexibility, the Government believes that it needs clarification to avoid too much weight being placed on the 1 in 20 flooding probability as defining the boundaries of floodplains. It is therefore proposed that the 1 in 20 flooding probability should take into account local circumstances such as where land which is not intended to allow floodwater to flow, floods and where areas which would naturally flood but are prevented from doing so by existing infrastructure or solid buildings. The 1 in 20 categorisation is therefore proposed as a consideration and discussion starting point.
In relation to the Vulnerability Classification, there are currently five different categories of flood risk for types of land and developments. Used in conjunction with the Flood Zones in Table D.1, the Vulnerability Classifications determine where it may or may not be appropriate to locate development. Four amendments to the Classifications are proposed;-
- water treatment and sewage treatment plants are to move to the "essential infrastructure" category;
- police, ambulance and fire stations which are not required to be operational during flooding are to be treated as "less vulnerable";
- where there is a need to locate facilities requiring hazardous substances consents with port or other waterside facilities or in coastal or high flood risk areas, these should be classified as "essential infrastructure"; and
- wind turbines for generating renewable energy should be classified as "essential infrastructure".
The consultation document can be viewed by clicking here.
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