Comprehensive groundwater control measures were required to dig the excavation pit for Zurich's Prime Tower and the neighboring Plattform building.

When work commenced on the Prime Tower, 15 dewatering wells were drilled for groundwater control, approx. 3,000 m of DN600 pipelines were laid to the outfall into the River Limmat (900 m of which was suspended from the SBB viaduct), and a CO2 neutralization system and return seepage system with automatic regulation in the apron of Zurich's central railway station. From commissioning to the end of the groundwater control measures for Prime Tower / Plattform, the systems pumped a total of 8,000,000 m3 of water, reaching peak volumes of 220 m3/h.