SURFACEWATER MANAGEMENT
The SEL Source Control System comprises a series of treatment phases which have been specifically developed to provide the ideal source control solution to meet the requirements of all current guidelines and legislation relating to SUDS, whilst incorporating traditional impermeable surfacings such as macadam, asphalt, concrete and standard block paving.
The main design principle of the System is Source Control, a cornerstone of good Sustainable Design. The System provides either infiltration or attenuation, incorporating multiple stages of water treatment and flow control within the constructed layers of car parks and other hardstandings, directly beneath the finished surface. The requirements for rainwater harvesting can easily be integrated in the SEL Source Control System.
What are SUDS? (Sustainable Drainage Systems)
SUDS are techniques for the management of stormwater which seek to replicate natural undeveloped catchment. SUDS are required to give a sustainable solution to deal with rainwater runoff from roofs and impermeable hard landscaped areas such as car parks, service yards and access roads.
Government policy through PPS25 (Planning Policy Statement) states that it is essential for the “integration of sustainable drainage systems into the overall site concept and layout”. Furthermore, “the planning system can further the use of sustainable drainage systems by persuading developers to adopt sustainable drainage systems wherever practicable, as part of all future development, if necessary through the use of appropriate planning conditions”.
Why Source Control?
Source Control is the treatment and controlled release of storm water runoff at or very near its source. Source Control is the preferred technique for the implementation of SUDS according to the Interim Code of Practice for Sustainable Drainage Systems, PPS25 and PPG3.
One of the main benefits of using the SEL Source Control System is that water is treated and subsequently attenuated or infiltrated as close to the surface as possible.
Employing the SEL Source Control System in this manner can lead to a dramatic reduction in the amount of earthworks required on site, and is particularly beneficial where specific problems exist, such as high water tables, contamination, or poor ground conditions (i.e. low CBR). The SEL Permavoid® unit is the only product of its type which is designed to create a structural void within the sub-base layer, substituting expensive imported aggregates.
Encapsulation for attenuation systems
The SEL Source Control System recognises the importance of ensuring the integrity of attenuation systems where it is essential that fluids are to be kept within the drainage system (e.g. where there is a potential of contaminants leaching into a protected acquifer). SELflex 1.0PP Geomembrane is a 1mm thick robust polypropylene sheet which requires joints to be fusion welded and subsequently air-tested. This in turn is protected by SELtex 300R, a 300g/mm2 Geotextile with exceptional dimensional stability consisting of a woven polyester core reinforced with needle-punched outer layers. This arrangement must be used where the engineer insists on a watertight system. If permeability rates are too low for full infiltration, but it is not essential to provide a watertight arrangement, then SELSudstex Permafilter Geotextile should be used.
Encapsulation for infiltration systems
sudstex
Health & Safety
The SEL Source Control System satisfies the designers’ statutory obligations as required by the Construction Design and Management (CDM) regulations.
- The risks inherent with traditional drainage systems are:
- Operatives working in deep excavations where there is risk of collapse
- Heavy lifting operations
- Operatives working within confined spaces
- Operatives exposure to contaminated sub-strata
- The SEL Source Control System avoids these foreseeable risks because it is shallow (generally less than 500mm deep), lightweight, installed above formation levels and contaminated zones.
Technical Services
To support architects, engineers and contractors in designing and installing the SEL Source Control System, our Design Services Department offers computer aided scheme design, hydraulic performance calculations and advice on installation. Supply and install packages are available for elements of the system – information available on request.
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