TAN15

The aim of TAN15 is to provide technical guidance which supplements the policy set out in Planning Policy Wales, 2002 (PPW).  TAN15 provides guidance on development and associated flood risk. It provides a framework within which risks arising from both river and coastal flooding, and additional rainfall run-off from development, can be assessed. I

In order to gain planning permission, all new development in Wales has to be tested against TAN15 for flood risk. The aim is to direct new development away from high risk areas or to justify development in high risk areas.

Flood zone categories have been identified by the Welsh Assembly and are published on the Development Advice Maps.

In Wales the flood risk zones are A, B, C1 and C2.

Zones C1 and C2 are the "at risk" categories based on the Environment Agency extreme flood outline at 0.1% (1 in 1000) or greater risk, with zone C2 being used when there are no existing flood defences.

Highly vulnerable development (which includes residential) will not generally be permitted in zone C2. Therefore, if development is to proceed in an area currently designated C2 there are only two possibilities: either the Planning Authority must consider the development to be "less vulnerable"; or by way of a Flood Map Challenge it must be demonstrated that the area justifies re-classifying as zone B or C1. To justify development in zone C1 two stages are required:

Stage 1 - Justification on planning grounds

The developer needs to demonstrate that the site's location in Zone C1 is necessary to assist, or be part of, a local regeneration initiative, strategy or employment objective.

Stage 2 - Flood Consequence Assessment report (FCA)

An FCA report is required for developments in zones C1 and C2.  For zone B, site levels need to be checked against the extreme flood outline levels.

The FCA needs to include the technical means of reducing the risk of flood damage to an acceptable level.  This follows on from an investigation of existing information and consideration of the proposed development in the context of the likely flood scenario. The assessment includes the following: