wellpoint

A wellpoint is a dewatering system used in civil engineering to lower the groundwater level around an excavation or structure. It consists of multiple small-diameter wells, known as wellpoints, connected to a common suction header. A pump draws water from the wellpoints, creating a locally lowered water table so that foundations, basements, trenches, or other works can be carried out dry.

Installation typically involves driving driving points into the ground, each containing a screened intake, and tying them to a header pipe that runs to a vacuum or centrifugal pump. Water collected by the wellpoints is pumped to a discharge point, such as a sump, ditch, or storm sewer. The arrangement allows groundwater to be removed from around the excavation region even as surrounding soil remains in place.

Wellpoint systems are most effective in permeable soils, such as sands and gravels, where groundwater can be drawn through the screens and pipes. Their effectiveness decreases in clay or silt and at greater depths, where drawdown is slower and may require more points or alternative dewatering methods. Design considerations include point spacing, screen size, pump capacity, discharge capacity, and the expected duration of dewatering. Environmental and safety concerns include preventing adverse effects on nearby wells or surface water, controlling the disposal of pumped water, and ensuring proper permits and professional design.

In other uses, the term WellPoint has also been associated with a health insurance brand formerly used by a company later branding itself as Anthem.