The SuDS Manual C753
About this book
The CIRIA SuDS Manual (C753), published in 2015 by CIRIA (the Construction Industry Research and Information Association), is the definitive UK technical reference for the design, construction, and maintenance of Sustainable Drainage Systems (SuDS). It replaced the earlier CIRIA publications C522 and C697 and represents the most comprehensive and up-to-date guidance on SuDS available in the UK, reflecting significant advances in understanding of both the science and practice of sustainable urban drainage. SuDS are drainage approaches that manage surface water runoff in a way that more closely mimics natural hydrological processes, in contrast to the conventional approach of rapid conveyance through pipes and culverts to receiving watercourses.
The SuDS approach emerged from recognition that conventional drainage systems contribute to flooding (by increasing peak flows in watercourses), water pollution (by carrying diffuse pollutants to waterways), reduced groundwater recharge (by preventing infiltration), and degradation of aquatic ecology. The manual introduces the "SuDS triangle" framework, which presents SuDS design as simultaneously addressing three objectives: water quantity management (controlling runoff volumes and peak flows), water quality improvement (reducing pollutant loads), and amenity and biodiversity benefits (creating attractive, ecologically valuable urban landscapes). Successful SuDS should deliver all three objectives, and the manual argues strongly against single-function drainage structures that achieve hydraulic performance without environmental co-benefits.
The technical guidance covers the full range of SuDS components: permeable paving, which allows infiltration through the surface and can manage both quantity and quality; green roofs, which attenuate stormwater and provide amenity and biodiversity benefits; filter strips, which are gently sloping vegetated areas that remove sediment and pollutants through filtration and sedimentation; swales, which are shallow vegetated channels that convey and filter runoff; filter drains, which are linear structures filled with permeable material; infiltration basins, which allow surface water to soak into the ground; detention basins, which hold water temporarily after storms; retention ponds, which permanently retain a water body providing water quality treatment and ecological habitat; and wetlands, which provide the highest level of ecological and amenity value. The manual addresses the design of SuDS "treatment trains" — sequences of multiple components that progressively treat runoff as it flows from source to receiving water. This approach recognises that different SuDS components have different strengths (some better for quantity management, others for quality or amenity) and that combining them achieves better overall outcomes than any single component.
Specific guidance is provided for the application of SuDS in different contexts including new developments, urban retrofits, highways, and contaminated land. The national and local policy framework for SuDS in the UK is reviewed, and practical guidance is provided on achieving planning approval, maintaining systems over time, and demonstrating performance. Sources: CIRIA (ciria.org); CIRIA Report C753 official publication; UK Environment Agency drainage guidance.