‘Grey infrastructure’ SuDS attenuation solutions typically collect rainfall from impervious surfaces, such as roadways, hardstandings and rooftops, and then store and discharge it below ground via a series of crates or pipes into the ground through infiltration, or into a local water body via a sewer or surface channel at a controlled flow rate.
‘Green Infrastructure’ (GI) is a complementary, alternative stormwater solution that mimics natural hydrology and seeks to improve water quality and reduce water quantity by capturing runoff as close to the source as possible and infiltrating, filtering, and storing it for reuse. SuDS practitioners often regard GI using vegetative, surface-based solutions as Best Practice.
StormTech chambers can be an integral part of a GI project providing additional scope for the designer to enhance performance and resolve technical issues. One example is where the infiltration capacity of the ground is poor and a downstream connection to a sewer or water body is not practicable. The additional storage provided by StormTech chambers installed below the surface-based SuDS feature can be used to retain a larger volume of storm water and enable infiltration at a slower rate.
StormTech can be used in a variety of GI applications. Pervious pavements, for example, allow the movement of water through the paving material and the StormTech system can be installed below the pavement. StormTech can also be used in combination with vegetative SuDS installations such as swales, infiltration systems, filter strips, rain gardens and bioretention systems. They can enhance the water storage capacity and pollutant removal performance. Downpipes directing stormwater from the roof of a building can also form an integral part of a GI/StormTech system, helping to replenish groundwater in a controlled manner, whilst filtering out sediments and nutrients from the water to decrease pollutant loads. StormTech can also be used as part of a sealed tank system providing rainwater harvesting.