If you have explored the possibilities for using infiltration as your main surface water drainage strategy and found that it is not possible to drain your site in this manner, then you will need to provide an attenuation system which drains to, by preference, a water course or, if not available, a mains surface water sewer or, as a last resort, a combined sewer system.
Extract from DEFRA National Standards for Sustainable Drainage
|SuDS Surface runoff not collected for use must be discharged to one or more of the following listed in order of priority:
The Skeletank range of products and design techniques has been developed to attenuate (store temporarily) rainwater using source control, a cornerstone of the sustainable drainage ethos. Controlling rainwater runoff at source using Skeletank products and design techniques reduces excavation, minimises the size and scope of pipework and associated manholes around the site and allows developers the opportunity to manage their cash flow more efficiently by reducing, or eliminating completely, costly upfront drainage works. The shallow nature of our systems also reduces the risk that connections to watercourses or mains sewers will need to be pumped.
Our systems can be used in conjunction with both pervious and impervious surfaces and are also ideal for use in landscaped areas.
A variety of techniques can be used to form underground attenuation tanks, from cost-effective ‘leaky tanks’ (where, dependent upon site conditions, structures may be encapsulated by inexpensive geotextiles) to fully sealed, geomembrane encapsulated systems or pre-formed modular units.
The use of Skeletank Controflow flow control chambers to manage the pass-forward flows from each plot addresses any concerns developers may have with meeting the adoption requirements of The Flood and Water Management Act 2010. Only pipework downstream of the flow controls will be subject to adoption by the relevant authorities.
Skeletank Solutions for Attenuation (choose one of the links below)