The architects working on the development approached UKFB to work together to design a system that could meet these planning stipulations. The amended plans deleted any enclosures separating the rear garden areas and potential blocking flood waters, and included the provision of a void beneath the proposed dwellings with a barrier system allowing the void to flood in the event of any severe flooding.
Undercroft flood storage of 3,500 cubic metres would be installed controlled by a specialist system designed by UKFB that would drop automatically to divert flood water into storage. This would be linked to the Environment Agency’s own telemetry monitoring system.
A Section 106 was agreed which included planning obligations to ensure the future maintenance of this system and to restrict occupiers from using the void for storage. This agreement gave unrestricted access to the Environment Agency for maintenance purposes. The flood mitigation measures ensured that the challenges usually encountered with stilted development were not realised with this site.
TAN15 requires that the risk of flooding at any proposed development is acceptable and appropriate to the scale and nature of the proposed development and that the consequences of flooding for the development are manageable to an acceptable level. As all of these stipulations were met by the design and no flood risk to other areas in the catchment could be evidenced, the development met the requirements of the TAN15 planning policy.
Environment Agency Wales were re-consulted on the amended FCA and plans on 11 August 2009. Their response received on 20 August 2009 stated:
”We have considered the new FCA above produced by MDC Limited, dated August 2009. We recognise and welcome that our previous advice has been taken on board and reflected in the above submissions to us. Based upon the information contained within this report we would raise no objection to this development from a flood risk perspective.”