The town awaits the results of its latest attempt to keep things dry and PCB-free. Good luck with that.
Construction of the orchestra pit for the new auditorium being built at Greenwich High School could start next week, if a newly reinforced dam prevents major leakage into the site.
Site contractor AMEC has .. bolstered the excavated area’s cofferdam with extra sheet piling. As a result, the dug-out section is ready for another pumping, scheduled for Thursday, of the approximately 9 feet of water sitting in it.
The dewatering process is complicated by the widespread ground contamination that exists at the high school site. The initial leakage into the pit caused the water table to tilt, and polychlorinated biphenyls [PCBs] in the ground to migrate.
A stronger cofferdam is expected to prevent major groundwater leakage into the pit and the extent of water-table disruption that precipitated the PCB migration. If the reinforcements do not work, the cofferdam will require more bulwarking before pit construction can begin.
“The problem was it was affecting the pressure in the level of the water in the field and causing flow and some migration of some contaminants in the field,” [BET member Bob Brady] said. “It was a manageable level from an engineering and technical standpoint, and the pump could have kept it [the pit] dry for construction, but it was causing problems with the PCBs. That seems to be the critical variable.”
Indeed it does.