Dredging Techniques and Technology to Facilitate a Large Dredge Project—Pier 4 Reconfiguration

In order to accommodate two ultra large container vessels simultaneously, the Port of Tacoma determined to reconfigure Pier 4. Consequently, significant dredging was required to realign the shoreline. Dredging included substantial slope cutback, requiring the removal of 465,000 CY (355,518 m³) of sediment. At its furthest point, the top of the slope necessitated relocating up to 330 feet (100.6 m) and re-shaping 2,000 feet (609.6 m) of shoreline. The project also included placing 100,000 tons (90,718.5 metric tons) of slope armoring rock. This paper will describe the process taken by the contractor, the port, and the design engineer to complete the dredging work on time and the methods used for interaction between each party to allow for a successful project amid multiple challenges. Various technologies were used to track the dredging process, including 3D viewing software that tracked the underwater positioning of the bucket. The expedited review methods ensuring dredging occurred per design and providing time-critical approvals will also be discussed.