FRA for Sites over 1 ha

Under PPS25, developments greater than 1 hectare (10,000m² / 2.47acres) in England require a Flood Risk Assessment (FRA), even if they are predicted to be at low risk from fluvial / tidal flooding (Flood Zone 1).

Flood Zone 1 is an area at low risk of flooding (less than 1 in 1000 chance in any one year) from rivers and the sea. Concerns relating to flood risk for large sites (greater than 1 hectare) are therefore in respect of surface water drainage.

The Pitt Review, which followed the summer 2007 floods, concluded that surface water was one of the primary causes of flooding – highlighting the importance of managing surface water runoff from new developments. Larger scale sites have the potential to generate large volumes of surface water runoff.

For existing Greenfield sites, the addition of hard surfaces and resulting decrease in permeability, will increase the risk of overland flow/flooding elsewhere unless properly managed. Indeed, even development on existing Brownfield sites, where the hard surfaces may actually decrease, the Environment Agency is becoming more stringent on allowable discharge rates – sometimes requiring restriction ‘Greenfield’ discharge rates.

Waterco’s understanding of flood risk and drainage issues means that we can fully address the requirements for FRA’s for sites greater than 1 ha.

For more information on what is included in this type of FRA, including our prices, see FRA Schedule Zone 1 greater than 1 ha

View Environment Agency Guidance on Development > 1 Hectare

Feel free to contact our team for an informal discussion.

Tel: 01824 702 220
Email: enquiries@waterco.co.uk

For information on flood risk and PPS25 can be found in Flood Risk Guidance