R2 AM Contaminated Harbor and River Sediment
Thursday, 17 November 2005: 8:00 AM - 11:40 AM in Ballroom 2

(ACC-1117-827117) Evaluation of sedimentation rates and solids transport in the Lower Passaic River.

Accardi-Dey, A.¹, Garvey, E.², How, C.¹, Desai, M.¹, Zamek, E.¹, Zeiner, C.¹, ¹ Malcolm Pirnie, Inc., White Plains, New York, USA² Malcolm Pirnie, Inc., Fair Lawn, New Jersey, USA

ABSTRACT- The Lower Passaic River has historically been subject to artificial deepening for navigation as well as contaminant-laden industrial and municipal discharges. Understanding the impacts of these activities is of major importance in planning remediation and managing the estuary under CERCLA and WRDA. To this end, a preliminary study of sediment deposition of the Lower Passaic River was performed using bathymetric and sediment core data collected from 1990 to 2004 from river mile (RM) 0 to RM 15. This presentation will focus on the lower six miles of the river due to the greater density of data in that area. In general, this analysis suggests that sedimentation rates (calculated by two independent methods: radioisotopes and bathymetry) are spatially heterogeneous from RM 0 to RM 6, varying from areas characterized as non-depositional/scour to areas with measured deposition rates greater than 5 inches/year. Moreover, differences between bathymetric surfaces (collected in 1995 and 2001) suggest that depositional rates vary significantly with water depth as well as river location, resulting in high sedimentation rates in the channel and low sedimentation rates on the shoals, opposite of that expected in an estuarine setting. Notably, a large depositional zone is located at the mouth of the Passaic River, characterized by a wide area of sedimentation rates greater than 3 inches/year. Integration of sediment accumulation rates show reach-by-reach variation in the net rate of sediment gain or loss. This evidence along with other geochemical data suggests that a net transport of solids is occurring from the Passaic River to Newark Bay. Sediment core evidence confirms the occurrence of high rates of sediment deposition while also providing evidence to characterize the impacts of historical flood events on accumulating sediments. These observations are important initial components of the overall body of evidence approach for the Lower Passaic River Restoration Project.

Key words: Passaic River, sedimentation rates, solids transport, radionuclides