Dewatering construction sites

Dewatering refers to the removal of groundwater and/or surface water from a site before construction work commences. This may be necessary on sites where there are trenches and excavations in which water can accumulate, in places where there is an inadequate slope for water run-off, or where there is a high water table.

Dewatering techniques typically include pumping and evaporation and may include the use of:

• Centrifuges.
• Vacuum filters.
• Filter presses.
• Drying beds.
• Sludge lagoons.

For more information, see Dewatering equipment.

Care should be taken when pumping to ensure water is being discharged somewhere suitable, otherwise erosion and other problems can occur. Best management practices must be followed when pumping water to lakes, wetlands or directly into storm sewers.

NB The SuDS Manual published by CIRIA in 2015 defines de-watering as: ‘The lowering of groundwater/surface water levels or the removal of water from a substance.’

Culvert, screen and outfall manual, (CIRIA C786) published by CIRIA in 2019, defines dewatering as: ‘The process of handling and/or reducing significant flows of water (especially groundwater) into an area where construction work is being undertaken.’

Short Guide, Lime Mortars in Traditional Buildings, published on 1 March 2013 by Historic Scotland, defines dewatering as: ‘The rapid loss of water that occurs when a mortar is applied to a porous substrate on which suction has not been controlled by dampening down.’

[edit] Related articles on Designing Buildings

• Freezing method.
• Geotechnical engineering.
• Ground conditions.
• Ground investigation.
• Groundwater control.
• Groundwater control in urban areas.
• Hydrogeological Impact Appraisal HIA.
• Passive dewatering.
• Pumps and dewatering equipment.
• Raising awareness of dewatering regulation.
• Sinkholes.
• Sludge.
• Soakaway.
• Sustainable urban drainage systems SUDS.
• Water abstraction licence.
• Water engineering.