It is standard practice for surface water flows from new developments to be restricted to match existing flows, or equivalent greenfield runoff flow rates, in order to minimise the impact of development upon downstream watercourses. This practice helps to safeguard areas downstream of the proposed development from flooding as a result of urbanisation of upstream sites.
As a result, water is stored at source, on the site. There are many options for provision of attenuation which include ponds, swales, cellular storage, granular storage or tanks, among others. We prepare designs to suit site characteristics, space, operation and maintenance, with sustainability and cost effectiveness as key factors in our specification.