BOUND SURFACING
Controflow SuDS baskets simplify inlets , outlets and erosion control for SuDS .
MAKING THE MOST OF MANDATORY SUDS
An important government review published in January announced that Sustainable Drainage Systems ( SuDS ) will soon become mandatory on developments in England , with implementation of Schedule 3 of the Flood and Water Management Act .
A public consultation later this year will help to shape the new approach to mandatory SuDS , with implementation expected during 2024 . National SuDS Standards will then be applied throughout England , largely based on experience in Wales where Schedule 3 has been in operation for some years .
New ‘ SuDS Approving Bodies ’ ( SABs ) will be set up within unitary authorities or county councils to approve SuDS schemes before construction of drainage systems on new and redeveloped sites ( except single buildings or permitted development under 100 m2 ) or connection to public sewers . The
SABs may also adopt and maintain approved SuDS that serve more than one property .
Nature Based Solutions SuDS are essential in the fight against flooding and pollution – particularly with overloaded sewers , urbanisation and climate change – but should also offer other benefits , including amenity and biodiversity . To achieve these goals , SABs will be looking for well-designed , multifunctional SuDS on or near the surface with flow controls .
For example , The Welsh Standards say : ‘ The SuDS approach mimics natural drainage , managing surface runoff at or close to the surface and as close to its source as practicable , controlling the flow ( volume and rate of runoff ) and providing a range of additional benefits ’. This approach has been demonstrated to cost less than conventional piped drainage , requiring no dedicated land-take for storage .
The key to successful SuDS design is water storage strategically deployed around a site within SuDS elements , such as green / blue roofs , swales , basins , ponds and permeable paving , forming discrete sub-catchments . Essentially , each sub-catchment should have a small orifice flow control to manage greenfield runoff rates . This concept avoids the extra land-take , pipework and costs of large , heavily engineered control devices and storage structures , such as pipes or tanks .
Essential Economic Flow Controls Developed specifically for SuDS , Controflow flow control chambers provide passive operation solutions to current SuDS requirements on developments . With their low cost and shallow construction – no more than 1.2m deep – Controflow chambers can be used more widely and wherever needed , to optimise flows from each sub-catchment , as well as at the site perimeter , while
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