"Digging Deeper in New York," Feature Article, November 2003

digging deeper in New York

If the third-largest port in the U.S. is too shallow, then dredge we must, says the Corps of Engineers.

by Gayle Ehrenman,
Associate Editor

A container ship that sails partly empty is a container ship that's not meeting its full earning potential. That's been the problem with the Port of New York and New Jersey: Ships have had to sail in only partly loaded, because the channels aren't deep enough to support the draw of a fully loaded ship.

That's why the Army Corps of Engineers' New York District has undertaken a series of estuary initiatives with the Port Authority of New York and New Jersey, and the states of New York and New Jersey to deepen the channels in the third-largest container port in the nation.

Part of this work involves deepening the Kill Van Kull channel, which connects Upper New York Bay with Newark Bay, and serves as the main route for ships docking at the busy New Jersey harbors of Port Newark and Port Elizabeth.
Currently, the existing 40-foot channel is not deep enough for the larger container ships now in use to come in fully loaded. The natural depth of New York Harbor is 20 feet.

Older container ships, which carry 3,000 containers, draw 45 feet. The newest class of ships, the post-Panamax and super post-Panamax classes of container ships (so named because they're too large to traverse the Panama Canal), can carry 7,000 to 8,000 containers, and draw up to 50 feet, according to Col. John O'Dowd, commander and district engineer for the Army Corps of Engineers' New York District.

The depth of the channels is driven by container traffic. The Port of New York and New Jersey is the largest container port on the East Coast. Three million containers per year pass through their channels, carrying $82 billion in ocean-borne cargo. It is the largest vehicle import/export handling port in the country, and the largest for refined petroleum products and cocoa imports, according to the Port Authority of New York and New Jersey.

In all, there are 240 miles of federal channel in the New York District. The Harbor Estuary Initiative is addressing roughly 10 miles of channel.

The backhoe dredge New York has been outfitted with a 13-cubic-yard bucket for digging through heavy-duty material.

The channel is divided into nine contract areas. To date, the initial phase of work in five of the nine contract areas has been completed. In many of these areas, work is ongoing to reach the 50-foot depth authorized by the Water Resources Development Act of 2000.

The Army Corps of Engineers began deepening the Kill Van Kull and Newark Bay channels to a depth of 40 to 45 feet in 1987, the first phase of the project, which was completed in 1995. Phase II began in 1999 and will continue until the end of 2004, at which time the Kill Van Kull and Newark Bay channels will have been deepened to 50 feet.

The Arthur Kill and Port Jersey have been dredged to their interim depth of 41 feet. Work will begin again next year to take them to the 50-foot depth that is currently authorized.

This dredging project is the second largest ongoing project for the Army Corps of Engineers. The only larger one for the Corps is the restoration of the Florida Everglades.

The cost for the port-deepening project is quite high. The Kill Van Kull and Newark Bay piece of the project was set at $733 million, for the initially budgeted depth of 45 feet. The cost to bring the New York and New Jersey harbors to 50 feet is $1.8 billion. The Arthur Kill and Port Jersey legs tack on roughly another $600 million. The Corps and the Port Authority of New York and New Jersey are sharing costs for the project.

BLAST OFF

Where the harbor composition makes it possible, the Corps is drilling and dredging. In areas such as Bergen Point, where the sediment is largely made up of diabase, a granite-like rock, they're blasting first.

In the Kill Van Kull, they're dredging nine different types of materials, each of which poses its own engineering challenge. What the Corps refers to as clean mud—essentially, mud that isn't contaminated by PCBs, heavy metals, and other toxic sludge—can go straight back out to the ocean, according to Joseph Seebode, who is chief of the New York/New Jersey Harbor Programs Branch for the Army Corps of Engineers.

The unclean mud, which is too contaminated to be safely returned to the ocean, is mixed with cement; the cement binds to the contaminants and keeps them from posing an environmental hazard. This material is being used to cap landfills in Elizabeth, Linden, Bayonne, and the Meadowlands in New Jersey.

The Army Corps of Engineers Harbor Estuary Initiative involves dredging roughly 10 miles of shipping channels between New York and New Jersey to bring them to a depth of 50 feet.

Other materials that the Corps is dredging include glacial till, which was left by the glaciers as they receded; red-brown clay, which Seebode says is hard to dig; and four varieties of rocks—serpentinate, diabase, sandstone, and shale.

Seebode is a civilian employed by the Army Corps, as are most of the engineers on the project, including, for example, project engineer Sherif Guirguis and team leader Sam Di Dato.

In the Kill Van Kull, one of the contractors carrying out the work for the Army Corps, Great Lakes Dredge and Dock Co. of Oak Brook, Ill., is using what it describes as the world's largest backhoe dredge. The backhoe dredge New York is outfitted with a 13-cubic-yard bucket for digging through heavy-duty material. It pulls up more than a garbage truck's worth of material in a single pass, Seebode said.

The dredge can support up to a 25-yard bucket and, depending on the boom in use, can dig to a depth of 80 feet. There are two drill boats, the Apache and MB 301, and four dredges (the backhoe dredges New York, Tauricavor, and Mariacavor, and the clamshell dredge Bean II) currently at work in the Kill Van Kull. An additional clamshell dredge, the Michigan, is at work in Port Jersey at Bayonne.

"Dredging the channels poses an environmental and engineering challenge. There's a lot of blasting, drilling, and dredging to be done, and all that material to be disposed of," said Seebode, an environmental engineer. "There's also a social challenge to the project, since we're working not far from where people live. We try to be sensitive to the concerns of the residents of the area, and be good neighbors."

The backhoe dredge New York has been described as the world's largest of its kind. It is one of four dredges currently at work in the Kill Van Kull.

Toward that end, the Army Corps outfitted the scows that carry off the dredge material with wooden floors, to dampen the sound of rocks being dropped from a height.

The project is using a liquid explosive for the blasting, and trying to do that during the day, so as not to disturb residents. According to Seebode, all of the blasting adheres to or exceeds the guidelines laid down by state and local authorities.

According to O'Dowd, the maximum allowable acceleration for a residential structure is 1 foot per second. So far, he said, blasting to prepare for the dredging operations has not exceeded 0.15 feet per second.

When all the work is done, the New York/New Jersey harbor will once again be deep enough to support fully loaded container ships, maintaining the port's viability.

SIDEBAR: SHAKE, RATTLE AND ROLL