Deep well systems are particularly suitable where large volumes of water must be pumped in highly permeable sand and gravel which permit a rapid recharging of ground water from surrounding areas, where the depth of excavation below the water table exceeds the lift capabilities of other dewatering techniques or where above ground apparatus might interfere with construction operations. Normally, individual wells are spaced at distances of as much as 15 meters. But soil conditions and the dewatering plan can cause spacing as close as just a few meters. Deep well pumps can lift water 30 meters or more in a single stage. The design of deep well dewatering systems are more complex than well points.
The deep wells can be installed from the surface around the construction area. They will lower the water table to 30 m or more in one single stage, with spacing from 6 to 30 meters. Depending on the soil condition Deep Wells typically consist of vertical bores, usually in the order of 800 mm to 900 mm diameter placed through the strata requiring dewatering.
