Technical description

Planning Policy Guidance note 25 was issued in July 2001, following the severe flooding of autumn 2000.

The aim of this document was to improve the understanding and awareness of those proposing developments within flood plains, with regard to flooding.

As part of the planning process, for sites within the flood plains, the Environment Agency (EA) will normally require developers to have a Flood Risk Assessment (FRA) undertaken.

This addresses the issues of how flooding could affect the development and how the development could affect flooding elsewhere. The assessment needs to be completed at an early stage, as the outcome will have a major impact on whether planning permission is granted.

Halcrow has been commissioned by various private developers to undertake FRAs, which have included both residential and commercial developments.

The first element of an FRA is the discussion with the Agency, to confirm the particular requirements to be addressed. Once these are known, information relating to the proposed development and the affected flood plain can be assembled.

River modelling may be required, depending on the scale of the development, to analyse the associated watercourses and flood plain. This information allows an understanding of how the level of flood risk will change due to the development.

An assessment report is prepared, which presents a recommended approach to achieving the required development with a minimum level of flood risk impact. When required, flood mitigation measures will be recommended.

Halcrow has the experience and expertise to develop these recommendations into a fully detailed flood alleviation scheme. During all stages of the assessment the consultation process with the Agency continues to ensure all their concerns are addressed.

Completed FRAs have included:

	Petrol station and retail outlet, East Peckham , Kent .
	Residential development at Furneux Pelham, Herts
	Re-development of a redundant public house in Caversham, Reading.
	Re-development of the Rose Revived Inn , Newbridge, Oxfordshire.
	Re-development of a residential home, Burnt Oak, London .
	Extension to a Warehouse, Wembley, London

Planning Guidance Note 25