The water table is extremely high here as it is just one block to the Hudson River. They could only excavate about 6 feet or so before hitting water. Very few Downtown or Waterfront projects in Jersey City have basements for that exact reason, hence the massive garage podiums on every building. 70-90 Columbus, the Trump Plaza towers, Urby Harborside, and a few others simply had a lot of piles drilled into the ground and a slab poured on top of them.