Attenuation means to temporarily store stormwater for a period of time, normally until the worst of the storm has passed. The water is then released to the sewer network.
Conder's extensive range of single and connected attenuation tanks form part of a SUDS scheme to provide such attenuation volume. The stormwater is collected by normal road gullies and routed to the sewer in the normal way. A controlled volume of this peak/high flow goes through to the mains.
During periods of high rainfall and run-off the manhole backs up and this excess flow is fed into the attenuation storage system. Over a period of time this stored water in the attenuation tank exits the system either by gravity or by pumped release at a regular rate, thus preventing flooding downstream.