Effect of changes in sediment and contaminant loads in Newark Bay on future disposal of dredged sediments

The Port of New York and New Jersey handled almost {dollar}133 billion in cargoes in 2005. Most of the Port's commercial facilities are located in Newark Bay. A heavy sediment load is discharged into it from upstream and downstream sources. Since the late 1880s, dredging has been needed in the Bay to provide navigable waterways for commercial shipping. The continuation of dredging is threatened by the lack of a sediment management strategy that provides long-term disposal planning. This thesis developed a disposal plan for the Bay during the period from 2005 to 2025.; A comparison of the sediment inputs and outputs suggests dynamic equilibrium is being maintained with the average annual accumulation (∼ 165,000 MT/y) being approximately equal to the mass routinely removed by dredging (∼ 157,000 MT/y). A mathematical model demonstrated that the critical shear stress for incipient sediment motion (estimated at 1 dyne/cm2) is frequently exceeded on the tidal flats and in the dredged channels. Simulations indicated that water-borne sediments in the upper portion of Newark Bay do not leave the Bay during ebb tide. Approximately 15 percent of the re-suspended sediments in the lower portion of the Bay were predicted to exit the system.; Newark Bay's sediment quality has been degraded influencing the acceptability of disposal practices. To assess the feasibility of ocean placement prior to 2025, a regression analysis of contaminant trends was performed. Target acceptability levels for mercury (0.4 ppm) and dioxin (10 pptr) were set based on current ocean placement site criteria. Mercury levels were predicted to be acceptable in the year 2049 and dioxin in the year 2040. Based on these results, further consideration of ocean placement of Bay maintenance material (forecasted at 240,000 m3/y) was consideration infeasible. Unacceptable new construction material generated during deepening projects was estimated at 150,000 m3/y from 2005 until 2014. Beyond 2014, the requirement returned to 240,000 m3. Combining requirements yields 6.2 million m3, plus 4.6 million m3 of ocean suitable material and 0.5 million m3 of rock. The total required disposal capacity was projected at 11.3 million m3 but may fluctuate significantly given natural variability of the Newark Bay sediment system.