By Nickolas J. Themelis

THE NEW YORK VIRTUAL HARBOR

The combined ports of New York and New Jersey are one of the most heavily used transportation arteries in the world, handling nearly 40% of the North Atlantic shipping trade.

The metropolitan New York area has grown around New York Harbor. The watersheds that feed into the Harbor are home to nearly 20 million people. The combined ports of New York and New Jersey are one of the most heavily used transportation arteries in the world, handling nearly 40% of the North Atlantic shipping trade. The Harbor has several problems but one of them has recently approached the dimensions of a crisis. The Hudson-Raritan estuary flow annually brings into the Harbor an estimated one to two million tons of sediments. These are fine particles carried over in the water runoff from the land, from marine sources and bank erosion. When the Hudson reaches New York Harbor, it widens and its flow velocity decreases. Also, an estimated 40% of the bottom surface area in the harbor is continually dredged for navigation purposes, Therefore, the inner harbor acts as a giant settling tank where most of the sediments carried down by the rivers settle to the bottom. From the seaward direction, the tidal flow also carries in large amounts of sand particles that settle in the dredged areas. It has been estimated that the accumulated sediments consist of nearly equal parts of riverine material and sand.

Keeping the channels open is a full time job for the NY/NJ Port Authority and the U.S. Army Corps of Engineers (USACE). In the past, 4-5 million cubic yards were dredged annually and disposed at offshore "mud dumps. However, ocean disposal at the last "Mud Dump Site," located about six miles off the New Jersey coast, was prohibited as of September, 1997, on the grounds that the concentrations of contaminants in the dredged "spoils" exceed ecologically safe limits.

It is interesting to note that this decision was reached at a time when all indications are that the Hudson is gradually recovering from human abuse in the past. There are many reports of fish species being sighted once again. Work by Steven Chillrud of Lamont-Doherty has shown that the concentrations of "heavy" metals (cadmium, lead, mercury, copper, zinc, chromium, and nickel) in the upper layer of sediments have decreased by 56% to 98% from the maximal anthropogenic concentrations reported in 1950-1960. The concentration of PCB's in sediments has also decreased by 90% since the 1970s.

Because of the prohibition to use the ocean dump site, the accumulation of contaminated sediments in New York Harbor has become for the states of New York and New Jersey a major problem that threatens the future of the ports and nearly 170,000 jobs in the shipping industry of this area. In response, the governors of the two states committed in 1996 a total of $130 million, $20 million of which was set aside for research and development of "decontamination technologies" and alternative ways of disposal, such as agglomeration and storage in extinct mines in Pennsylvania.

Over the centuries, the waterfront in this area, as in other urbanized coastal areas, has been developed for the convenience of humans and with relatively little consideration on the effect of this development on the rest of the biosphere and the Earth resources. The present major problem faced by New York Harbor is as clear an indication of the capacity of nature to "bite back" as the hole in the ozone layer and the first manifestations of global warming. This was the subject of an important workshop of the New York Academy of Sciences last September: "Industrial Ecology and Pollution Prevention: Applications to New York Harbor."

To understand and deal effectively with dredging and other problems of the Harbor, it is necessary to develop a reliable quantitative model that describes the mass flows of waters, sediments and contaminants in and out of the Harbor, point and dispersed sources and sinks of contamination, transport and chemical rate phenomena that affect contaminant concentrations, biological effects of contaminants on fresh and sea water ecosystems, and how contaminant flows and distributions have changed with time and are expected to change in the future. Such a comprehensive model, subject to continualtesting and validation, can be used to assess the effect of various measures that may be taken to deal with the current problem of contaminated sediments and with future problems that impact on the welfare of New York Harbor. The knowledge imparted by such a model will also be useful in designing post-industrial waterfronts with full understanding of their broad ecological impacts.

The Earth Engineering Center, the engineering component of Columbia's Earth Institute, has proposed to develop such a model that will draw on two intellectual resources:

First, an enormous amount of scientific work has already been carried out on the physical, biological and anthropogenic phenomena in the Hudson estuary and New York Harbor. The Hudson River Foundation (HRF) alone has compiled a list of nearly 500 studies and technical papers resulting from work on the Hudson estuary supported by the foundation. EPA, USACE, USGS and other agencies have also sponsored or carried out many scientific and engineering studies on the Harbor. The results of all such studies will be incorporated in the proposed model so that the need for collecting new data will be limited to filling existing gaps and monitoring changes in the future.

Second, the compilation and manipulation of such a diversified data base is now possible by means of computers and the software of Geographic Information Systems (GIS) technology that provides for multidimensional visualization and interactive analysis of data.

The platform of this model will be a comprehensive GIS-based representation of the waters, land and human activity that have an effect on New York Harbor. The model will superimpose on geographic and bathymetric information data bases on mass flows of water, sediments, contaminants and sands into the harbor, concentration profiles of contaminants, phytoplankton growth and decay, and other hydrodynamic, water quality and biological parameters. The geographic area to be modeled will include the lower Hudson, Passaic, Raritan, Hackensack, Harlem and East Rivers, New York Harbor and the ocean shipping approaches. The model will be comprised of several data layers linked together to allow for interactive analysis.

We have called this model the New York Virtual Harbor because it will provide a visual representation of the harbor and its surroundings in several "dimensions," allow the analysis of technological alternatives for maintaining and improving the Harbor, and project the effects of pollution prevention and remediation measures.

The use of GIS technology is not new to mining and civil engineers who have had to deal with the design of mammoth undertakings, such as mines and bridges, that spread over large areas of land. What is new in this effort will be engineers linking arms with Earth and biological scientists, with government agencies, and with the many environmental non-profit organizations who are concerned with the well being of the Harbor, to develop a reliable and credible tool for assessing various technological and policy measures. Columbia University is well located to be the cradle of this multidisciplinary activity, multi-institutional activity.

Preliminary work has included setting up a computer facility using the GIS model of the Harbor provided by USACE (Nickolas Themelis and Fletcher Griffis), an analysis of remote sensing and surface data on phytoplankton growth related to anthropogenic emissions (Karl Szekielda, EEC), and a flow model of Hudson, tributary, and tidal flows (Ross Bagtzoglou, Civil Eng.; see www.ldeo.columbia.edu/estuary). An offshoot of this work has been a proposal for beneficial use of dredged sediments (Pelham Bay Wetland; Griffis, Lex van Geen, Lamont-Doherty, and Paul Mankiewicz, Gaia Institute).

Close liaison with the NY/NJ Harbor Estuary Program and the Comprehensive Conservation and Management Plan (CCMP) will be provided by Tom Wakeman who is Dredging Program Manager at Port Authority and also a member of Columbia's Earth Engineering Center. A recent publication by Tom Wakeman, Dennis Suskowski (HRF) and Peter Dunlop of Port Authority describes in detail the dredging problem and the strategy to be followed. It states that an important next step is to create a conceptual model that depicts all sources and sinks that contribute to the flux of sediments and contaminants into the Harbor. We hope that the New York Virtual Harbor will become a significant academic contribution to this model.

The project has been much encouraged by the recent offer of the NJ/NY Clean Ocean and Shore Trust (COAST) to assist in the creation of a full-time post doctoral position at the Earth Engineering Center dedicated to the goals of the New York Virtual Harbor. Columbia engineers have in the past contributed much to the technological development of New York. Lamont Doherty scientists have carried out important studies on the quality of waters in the Hudson estuary (James Simpson, Peter Schlosser, and Steven Chillrud amongst others). The New York Virtual Harbor offers the opportunity for Columbia University to become an intellectual force in the future of a national resource and transmit the lessons learnt to other coastal urban centers.

Nickolas J. Themelis is Stanley-Thompson Professor of Chemical Metallurgy and Director of Columbia's Earth Engineering Center. Currently he is acting Chairman of the Department of Earth and Environmental Engineering (Henry Krumb School of Mines) of the School of Engineering and Applied Science.
He can be contacted at:
1047 Mudd, Columbia University, New York, NY 10027.
Phone 212 854 2138;
Fax 212 854 5213.
email: njt1@columbia.edu