Practical tips for groundwater lowering

Groundwater lowering with the Wellpoint system is one of the most widely used civil engineering applications for dewatering construction sites. Despite the popularity of this system, the pumping technology used is often incorrectly sized or the sizing is based on incorrect parameters.

For the success of a wellpoint system, it is important to consider the sufficient number of wellpoints. Each wellpoint can only pump a certain amount of water and this determines how much volume the associated dewatering unit must pump.

Wellpoints with a diameter of 2-inch or 50mm can in practice convey up to 3.0m³/h of water under unstressed water conditions. With 100 filter lances or wellpoints, this results in 300m³/h in theory. In practice, this value decreases when the steady state is reached due to the decreasing water volume and the almost constant air volume. It should therefore be noted that the number of wellpoints must be adapted to the air/water capacity of the lowering unit.