A catchment is defined as an area of land that sits as a depression from the surrounding landscape and collects flowing water, usually from rain that flows down stream. A catchment can be an area of land that is either man-made or naturally occurring. In the context of trenchless technology, sewage wastewater networks are divided into catchments where sewage from various sources is collected. In places where there exists a sewer network, and rehabilitation has to be undertaken, the network is divided into mini catchments. This makes it easier to determine extent of infiltration of storm water, ground water or industrial effluents into the sewer system.
Trenchlesspedia Explains Catchment
To conduct sewer network rehabilitation, like pipe relining and structural renewal of sewer mains, sewer catchments are segregated based on population, inflow of sewer and ground water infiltration rates. Drawdown tests are carried out to determine the flow and pump rates in sewage pumping stations. The catchments are also individually inspected for infiltration and ex-filtration. Once the rehabilitation needs of the different catchments are assessed, pipe relining work and other necessary rehabilitation and maintenance processes can be carried out in a cost effective and time saving manner. Catchments that do not need rehabilitation can be used as control catchments while the other catchments undergo relining or maintenance work.