Chapter 8 Groundwater control

Groundwater control techniques can be used to avoid or mitigate groundwater problems that can affect below-ground construction works, both in the temporary case during construction, and under permanent or long-term conditions. There are two main categories of groundwater control techniques: pumping methods (also known as construction dewatering), whereby groundwater levels are lowered by pumping from an array of wells or sumps; and exclusion methods where low-permeability barriers (cut-off walls or zones of ground treatment) are installed around an excavation or structure to prevent or reduce groundwater inflows. Often a combination of these two approaches is appropriate. This chapter describes the characteristics and application of groundwater control methods.