Groundwater control at ports and for other marine works has the obvious constraint of close proximity to open water which around the UK may have significant tidal fluctuations. This implies the potential for rapid rises in groundwater levels if pumping is interrupted for any reason. Since discharge may be direct to the marine environment careful attention must be paid to discharge water quality. Also where cofferdams are being drained coordination is required for the removal of fish which may have become trapped in the cofferdam. WJ has dealt with these constraints on a range of projects such as the Thames Gateway Port, the Tyne Barrage, the Cardiff Bay barrage, immersed tube tunnel cofferdams at Conway, Cork (Ireland) and Medway plus many other smaller projects.
WJ has also installed wells into the bed of the Thames to dewater a tunnel below. Divers were required for pump installation with generators and control cabins located on a moored barge above. Experienced drill crews and reliable pumping with full auto-restart backup systems are always an essential requirement for dewatering for port and marine structures.