Newark Bay Study - Passaic River Public Digital Library

1.4.2.1 A Macro-Scale Solids Balance for Newark Bay
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It is informative to discuss sediment transport in Newark Bay in the context of several earlier
investigations of this water body. Perhaps the most important study in this regard was the work of
Suszkowski (1978). This study, which focused on sediment transport dynamics in the Bay, included
detailed analyses of both fluid and sediment transport. Specifically, Suszkowski implemented a
monitoring program that was approximately one year in duration (April 1976 – April 1977), during
which time he made approximately monthly measurements of conductivity (converted to salinity),
temperature, dissolved oxygen (DO), pH and total suspended solids (TSS). Stations were located
slightly to the north of Newark Bay in both the Passaic and Hackensack Rivers, at the mouth of
each of these rivers at Newark Bay, at 3 locations along the central axis of Newark Bay, at the
approach to and near the entrance of each of the Kills, and at the point where the Kill van Kull
enters NY Harbor. Each station was sampled at 3 depths, surface, mid-depth and near the bottom.
He also analyzed surface samples for TSS in both the Passaic and Hackensack Rivers on a daily
basis, though the dataset for the Hackensack River was not complete. Numerous surface sediment
samples were also collected. While somewhat dated, their consistency with more recently available
information (e.g., Pence, 2004) indicate that these data and related analyses provide a useful
characterization of more contemporary conditions in Newark Bay, over both time and space. As
such, they are judged to be of use for current planning purposes.
The TSS profiles also provide a useful characterization of the suspended solids distribution
in the system. For example, the TSS concentration typically averaged between 1 and 3 mg/L across
all stations, and it was as high as about 5 mg/L during the spring high flow months. Further, the
average bottom sample TSS concentrations (averaged across all stations) were consistently higher
than the surface samples over time, and they had a slightly lower volatile solids content as well. This
was attributed to a combination of factors, including increased productivity in the surface waters,
decomposition of organic content during settling from the water column, and differential settling
rates for organically rich versus inorganic particles.
The data reported by Suszkowski (1978) showed that the suspended solids levels in Newark
Bay exhibited a spring maximum, possibly a result of elevated spring runoff from upland areas.
Elevated TSS levels were also observed in association with a turbidity maximum in the vicinity of
mid-Newark Bay, and in the vicinity of localized dredging activities. Evidence of a significant but
short-lived turbidity maximum was also reported for one of the surveys where sampling was
conducted near the time of “ebb strength”. This latter increase in TSS levels was attributed to
resuspension of bottom sediments by tidal currents, since low upstream flow conditions prevailed at
the time of sampling. This phenomenon will require the use of an intra-tidal model if it is to be
explicitly represented.