Deep wells are generally used for groundwater control in excavations which extend beyond the suction lift of surface mounted pumps. A drilling rig is used to install a series of wells around the excavation and the wells can be constructed to dewater multiple aquifers simultaneously or, by using carefully placed seals a lower aquifer can be dewatered whilst maintaining the piezometric head in the upper levels. This can be useful in protecting nearby structures.
Wells are best suited to homogeneous granular aquifers which extend well below the depth of the excavation. By careful selection of the right filter material and correct development of the well, the pumps will produce only clear water with no suspended fines which makes disposal of the water much easier.
The pumps are powered by three phase electricity and we are able to provide and install the generators, cabling and distribution system for each pump. We have also developed a level control system for borehole pumps which will prevent the pump from failure due to overheating and allow accurate control of the water level across the site where the permeability is low by stopping and starting the pumps as required.