EIDW

Deep Well Dewatering System

Deep well systems are used in 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. Deep well systems consist of one or more individual wells, each of which has its own submersible pump at the bottom of the well shaft. Such systems are particularly suitable where large volumes of water in highly permeable sand and gravel areas permitting rapid recharging of ground water from surrounding areas exist. 

                    

Normally, individual wells are spaced at an approximate distance of 50 feet apart. However, depending upon soil conditions and the dewatering plan the spacing may need to be just a few feet apart. Individual well capacities are from 21 to 3 000 gallons per minute and with total systems the capacities can be as high as 60 000 gallons per minute have been successful.
Deep well pumps can lift water 100 feet or more in a single stage and the variation of the typical deep well system is a pressure within an aquifer. Deep well pumps require no pump as the water is forced to the surface by its own pressure. To boost the water flow a vacuum pump is frequently used.

Deep wells are often sealed to prevent intake of air or water from higher aquifers. Although deep wells are often more expensive to install and maintain, in many applications they can be the most economical choice.

EIDW dewatering engineers will design the most appropriate system for the conditions and submit a competitive price for the job at hand. A typical deep well consists of a drilled hole within which is a lower screened casing which admits water to the pump; an upper casing which prevents soil from reaching the pump and, within the casing, the pump and its discharge pipe.

The discharge pip supports the pump to which it is attached. Electrical wiring for the pump motor runs between the discharge pipe and the casing. The space between the drilled hole and the casing is normally packed with filter material (for example, coarse sand and/or gravel) to minimize the pumping of solid material from the soil surrounding the well.