Recent innovations using flow controls with concrete block permeable paving help meet regulatory requirements for sustainable drainage systems (SuDS).
SuDS and techniques such as concrete block permeable paving are essential tools in the fight against flooding and pollution. By its very nature, concrete block permeable paving is uniquely placed to help meet the multifunctional requirements for SuDS on developments. Of course, hard surfaces are necessary anyway – whether for traffic, parking, cycling, walking or play. But permeable paving also provides an inherent drainage system, addressing both flooding and pollution issues by attenuating and cleaning water runoff at source.
After more than two decades of use, concrete block permeable paving has proved to be a predictable, reliable and low-cost SuDS technique. Its capability to attenuate water flow during rainfall for gradual discharge is well known. But this principle is transformed by considering distinct storage ‘sub-catchments’ of permeable paving using straightforward devices with an orifice – accessible for observation and adjustment if needed – controlling outlet flows.
This enables water storage to be strategically deployed around a site, with the flow controls demonstrating straightforward compliance to local authorities as part of the SuDS design approval process. Dedicated water storage on valuable land and associated excavation and construction costs are avoided, and this technique can help satisfy SuDS requirements on high-density urban schemes without expensive storage structures. It is also useful for controlling flows within the pavement construction, maximising storage on sloping sites and increasing treatment times to optimise removal of pollutants.