The project involves the proposed redevelopment of Dorset Green Technology Centre in Purbeck together with adjacent agricultural land. Mixed use plans for the combined 75ha site include new offices, a primary school, student accommodation and a hotel within the Technology Centre, as well as new housing and the creation of a country park on the undeveloped land to the south east.
Waterman was commissioned to undertake a Flood Risk Assessment to support an outline planning application.
The Environment Agency Flood Zone map indicated that there were two flood flow paths through the central area of the Site, which were constraining the potential for redevelopment.
Waterman undertook a detailed flood modelling study which demonstrated that the Environment Agency’s modelled flood flows in the River Win were over precautionary and confirmed that the majority of the area proposed for redevelopment was actually at a low risk of flooding.
The Flood Risk Assessment and hydraulic model outputs have been approved by the Environment Agency, who amended their Flood Zone Maps to reflect Waterman’s flood mapping.
This removed the abnormal flood management costs associated with land raising and the provision of compensatory flood storage, while freeing up previously sterile land for development.
A sustainable drainage (SuDS) strategy was also developed to capture runoff at source through living roofs and permeable paving and convey it through swales to balancing ponds. This reduced peak flows and improved water quality discharged to the River Win, as well as providing biodiversity and amenity benefits.