Dey Street Tunnel: The challenges of a design build project in a congested urban setting

The excavations for the project were approximately 40 to 45 feet (12 to 14 m) below the ground surface which places them in the stratified silt and silty fine sand stratum.

The local groundwater elevationwas approximately 104 feet, which put the Cortlandt Street Station concourse below the water table, and the Fulton Street Station concourse above the water table.