Aquaflow SuDS attenuation system
The Aquaflow Attenuation system consists of a permeable paving surface on top of a graded stone laying course. An upper layer of Inbitex Geotextile is used for separation, filtration and pollution control. Next is a graded sub-base stone that allows storage of collected storm water. This is sealed by an impervious membrane creating a tank within the excavation. The collected storm water is then released at a controlled rate to the watercourse or can be reused in conjunction with rain water harvesting systems. This system can be used on domestic and commercial projects.
Note: Formpave specifications shown for the Aquaflow SuDS Attenuation system are for guidance purposes only. For a detailed specification relative to your individual project please contact us on
01594 836999 or click here for Aquaflow SuDS design service.
Aquaflow System Components
Subgrade: the strength of the ground measured by carrying out a California bearing ratio (CBR) test. The results will influence the structural design of the system. Where contamination or a high water table is present then a fully welded SC Membrane will be required.
The patented Aquaflow system requires less excavation than other systems, providing cost and labour savings.
Kerb: provides a fixed edge for the system, ensuring that all components remain in place.
*Inbitex®: acts like a sieve, filtering harmful pollutants and hydrocarbons from the collected storm water. Inbitex layers improve the water quality and remove the requirement for additional water treatment or filtration.
*SC Intergrid®: SC Intergrid is a ground stabilisation layer which reduces construction depths and in turn lowers construction costs.
*SC Fin Drain: placed to the side of the excavation at the lowest point of the sub-grade allowing the system to drain. High resistance to crushing so can be used in all applications. Wrapped in Inbitex Geotextile providing another layer of water treatment.
*Top Hat Seal: pre-formed watertight sealing to secure the membrane to the outlet pipe.
*SC Membrane – forms tank to retain sub-base and water. Joints can be taped or welded depending on application. Where welding is required a high grade membrane is required, SC GT Membrane.
*SC GT Membrane – used for 100% watertight welded tank and specialist applications
Lower Sub-base: 10-63 clean crushed angular stone graded to work in conjunction with the SC Intergrid and to provide 30% voids. Storage for the storm water is accommodated with the voids in the sub-base.
Upper Sub-base: 5-20mm clean crushed stone which provides 30% voids to create storage. Smaller grading allows for ease of construction creating a more even surface for the upper Inbitex layer and laying course.
*Formpave distribution tanks: used for connecting rainwater downpipes and other impermeable areas for drainage to the Aquaflow system. Can be used in trafficked areas. Available in three different sizes depending on catchment area - click here for more information
*Inbitex®: upper layer of this geotextile provides initial filtering and cleansing of run-off, and prevents smaller aggregate filtering down and clogging lower layers.
Laying Course: 2-6mm clean stone which provides a flat, even surface for the blocks, without impeding permeability.
Permeable Paving Blocks: This is the visual layer, with Formpave’s uniquely shaped blocks being available in a wide variety of shapes, colours and finishes.
Grit: 2-4mm grit is brushed between the blocks to prevent movement, whilst still allowing permeability.
All of the above components are part of the patented Aquaflow system. All components must meet the specific requirements and be installed correctly for the warranty to be applied – click here for design services.
*These product are supplied by:
TCS Geotechnics - Tel: 01942 218597