Advice on dewatering
Dewatering is often carried out for the purpose of performing earthworks under dry conditions. However, lowering the groundwater table can be risky, since it can damage the surrounding area through dehydration, settling, salinisation or the displacement of contaminants. A thorough preliminary investigation can provide advance assessments of potential risks, thereby enabling timely measures to be taken.
Our Sweco experts carry out risk assessments and try to find feasible and sustainable solutions in collaboration with the client. Together with the client, we examine at the dewatering concept, taking into account the geohydrological parameters in the area, the desired drainage depth and the structure of the construction pit (or trench). We determine the influence of the drainage on the surroundings using analytical or numerical calculations, always in conformity with the “Guidelines on drainage for environmental protection” (Flemish Environment Agency, 2021). We present the results in the form of maps showing the groundwater levels and reductions at various points during the dewatering, supplemented by graphs or tables showing the drainage flow during the dewatering period.