Water & Wastewater Treatment Magazine
Issue link: https://fhpublishing.uberflip.com/i/1223154
www.wwtonline.co.uk | WWT | APRIL 2020 | 43 New standards clear up SuDS uncertainty Dr David Smoker, chair of the BPF Pipes Group's SuDS and Surface Water Working Group and technical director at ACO Technologies, looks at the latest legislation in this area. W ith increas- ing weather extremes, such as autumn's excessive rainfall, surface water manage- ment and SuDS (sustainable drainage systems) in particu- lar, have become even more important and higher profile. For each planning applica- tion, even for smaller develop- ments, a plan for surface water management now has to be submitted. However, even though there are more and more SuDS schemes in place it could be argued that the acceptability of a design is largely at the discretion of a particular engineer, planner or lead local flood authority. Achievable SuDS In order to support the plan- ning application CIRIA'S SuDS Manual (C753: 2015) provides excellent guidance on the design of SuDS to achieve the 'four pillars' – quantity, quality, amenity, biodiversity – but achieving all four may not be feasible on a specific site. However, in the current climate (no pun intended) a plan to achieve the control of volume, flow rate and quality of water being discharged from a site may be the primary concern for the planner. Equally, infiltration of surface water may not be pos- sible for reasons of geology or ground contamination, leading to attenuation. C753 recognis- es this and includes under- ground attenuation systems, also known as geocellular systems, as legitimate SuDS components. The other issue with SuDS has been who takes responsibility for the ongo- ing maintenance. In England, local authorities have really only considered adoption of those in public open spaces. Whilst commercial develop- ments have o'en been quite happy to retain the ownership and maintenance of their own SuDS, this has le' a large number of mainly residential developments in a sort of limbo – does the developer retain ownership, contract a third party maintenance com- pany or transfer the ownership to a residents' management group? With the publication of Ofwat's 'Sector Guidance in The Knowledge: pipes & drainage