If you’re thinking about installing geocellular crates there are two options available for how the system can work. A soakaway, as the name suggests soaks water back into the soil and attenuation, which holds and redirects the water to another place.
In soakaway schemes the system. In wrapped with a permeable membrane. Water is collected and slowly soaks back into the ground through and infiltrations process in line with the natural rate to avoid flooding and water-logged ground.
For more information on soakaway schemes check out these articles:
In an attenuation scheme water is stored within the system and with flow controls, is slowly released back into a watercourse or sewer system. Legislation has seen more and more pressure on local planning authorities and specifiers to implement systems to prevent flooding. The objective is to design a system to deal with the flow at the source rather than transferring the problem further down the watercourse.
Basically, attenuation means to temporarily store storm water for a period of time, to then release back into a watercourse or sewer network. The storm water is collected and routed into the sewer the normal way but with the use of flow controls, this allows a controlled volume to flow through into the main system. During a heavy rainfall, the rest of the excess water, which would be backing up at this point, is fed into the crate system where it is held until its ready to re-join the main system. When this happens, it will return back into the water system and exit through the flow control at a regular, predevelopment rate; preventing flooding downstream.