Last Updated: December 8, 2017

Definition - What does Dewatering mean?

Dewatering is the process of draining an excavated area that is flooded with rain water or ground water before construction can start. It is carried out where there is an accumulation of ground water at the site where water or sewer lines have to be laid, or excavation for foundations and basements has to be carried out. Dewatering pumps with high air-handling capacity are used to remove the water. Using trenchless technology, it is possible to carry out dewatering with limited breaking of surface strata and minimum disruption to traffic.

Trenchlesspedia explains Dewatering

In many places where there is a short time frame and high cost of traditional dewatering, horizontal directional drilling is carried out to place perforated pipes below the water table. This method was undertaken in Melbourne, Australia, to install a dewatering system for the AU$6 billion Level Crossing Removal Project. This helped to create a comfortable environment to carry out bulk excavation work below the train lines without disruption of services. This method of dewatering using HDD is cost effective and time saving.

Another method of dewatering using trenchless technology is the well point system, where well points at specific depths are placed around the excavation site. The pump produces a vacuum that lifts the groundwater out through the wellpoints. The water is then safely discharged away from the site.

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