Siting a large deep water transshipment port

27 December 2014


The new Panama Canal locks are being built to accommodate ships with a total fresh water draft of 50 feet (15 meters), a beam of 160 feet (49 meters) and a length of 1,200 feet (366 meters). This compares with the current canal limits of about 41 feet (12 meters) of draft, 110 feet (30 meters) of beam and 1,000 feet (305 meters) in length. Once opened, the new canal is expected to have a significant impact on U.S. ports with the primary impact expected to be substantially increased traffic at the US East and Gulf Coast ports and a decrease on the U.S. West Coast ports. This is due to the fact that the new canal will eliminate the cost advantage that West Coast ports currently have in handling large container ships arriving from Asia whose loads are then moved to the East Coast via rail. The much larger ships able to transit through the new canal will shift the cost and time advantage from the West Coast ports to the East Coast ports that are able to handle the larger ships.


Reece Frank Shaw
Manager of Port & Marine Development, Bechtel

According to the U.S. Army Corps of Engineers (USACE) Institute of Water Resources there are likely to be two additional impacts:

  • To take full advantage of the larger vessels coming through the canal, a large deep water transshipment port located either in the Caribbean or along the U.S. coast is likely to be developed. The largest vessels would unload containers at the transshipment port for reloading on smaller feeder vessels for delivery to other U.S. ports with less draft and capacity.
  • On the export side, the ability to employ large deep draft bulk vessels is expected to significantly lower the delivery cost of U.S. agricultural exports to Asia and other foreign markets. This would have a significant impact on the total quantity of U.S. agricultural exports and commodities moving down the Mississippi River for export.

Most existing U.S. East Coast ports are unable to handle the New Panamax ships and have a maximum draft of about -40 feet (-12 meters) or less. However, there are exceptions including the ports at Hampton Roads and Norfolk (-50 feet [-15 meters]) in Virginia, Baltimore (-50 feet [-15 meters]), and New York (-50 feet [-15 meters]). In addition to these, Charleston, with a -45-foot (-14-meter) channel depth and nearly 5 feet (1.5 meters) of tide, can accommodate New Panamax vessels at high tide during a two-hour window and Savannah can do so marginally with –48 feet [-14.6 meters] of dredged depth.i

For Gulf ports, Gulfport, New Orleans, Mobile, and Houston have maximum berth depths of -45 feet (-14 meters) or less. None of these ports are currently funded to be deepened to -50 (-15 meters) feet.

Ports that are hoping to accommodate New Panamax ships must also consider air draft (the distance from the surface of the water to the highest point on a vessel). The New Panamax ships have an air draft of 201 feet (61 meters). The eastern seaboard ports of New York and New Jersey are constrained by the Bayonne Bridge, which has an air draft 151 feet (61 meters). The Port of New Orleans is constrained by both channel depth and air draft. The federal channel in the Mississippi River is maintained to a depth of -45 feet (-14 meters) up to Baton Rouge, and the Crescent City Connection Bridge in New Orleans—the farthest downstream bridge on the Mississippi River—has an air draft of 170 feet (52 meters) at low water and 155 feet (47 meters) at high water.

The ports hoping to take advantage of the shift in cargo flows must also consider the movement of goods from the ports to inland destinations. Therefore, landside capacity and good highway connectivity is essential in being able to handle and move the large quantities of containers and bulk products quickly and efficiently to and from onward locations. This is often one of the most serious problems facing existing ports, many of which have highly congested and inefficient inland connections created by dense existing city development surrounding the port.

An alternative approach: America's marine highways

The federal government has been promoting the rehabilitation and improvement of America's Marine Highways as an alternative to highway congestion on roads and railroads. These navigable waterways have been designated by the Secretary of Transportation and have demonstrated the ability to provide additional capacity to relieve congested landside routes serving freight and passenger movement.

The program is designed to focus on the integration of Marine Highways into the nation's surface transportation system, providing seamless transition across all modes by leveraging marine services to complement landside surface transportation routes.

Marine highway centered on the Mississippi River

The Mississippi inland waterway system is an inland waterway system that connects more than a dozen Midwestern states with the Gulf of Mexico. The corridor includes the Mississippi and Illinois Rivers from New Orleans via St. Louis to Chicago and on through Louisiana, Mississippi, Arkansas, Tennessee, Missouri, and Illinois. It includes connecting commercial navigation channels, ports, and harbors.ii

At 2,348 miles (3,779 kilometers) in length, the Mississippi River is the second longest river in the United States and 92 percent of the nation’s agricultural exports are produced in its basin. Sixty percent of all U.S. grain exports move on the Mississippi River and the largest port in the United States (by tonnage) is the Port of South Louisiana which is located on the Mississippi at LaPlace, Louisiana. The Port of New Orleans handled 476,413 containers (TEUs) in 2011, most of which also move inland on truck and rail.iii

It is extensive but limited to depths of less than -15 feet (-4.6 meters) for the most part. As noted above, the port at New Orleans has a maximum berth depth of less than -45 feet (-14 meters), limiting the containership capacity to less than 5,000 TEUs. Under such circumstances, ports along the Mississippi are primarily handling barges loaded with agricultural commodities, which implies a highly seasonal traffic (end of the summer and fall).iv

The Lower Mississippi ports are dominated by dry bulk trades like coal, grains and ores, along with a wide variety of other commodities. When viewed from the perspective of the ability of inland waterways to support enhanced export opportunities that a global fleet of larger ocean going vessels represent, those inland waterways that serve a hinterland with desirable export commodities are of particular interest. Logistics/transportation entities at New Orleans have developed new methods of loading commodities to containers that previously only moved in bulk.v

Deep-water Gulf Coast transshipment hub options

There are basically three Gulf transshipment hub options that would support the U.S.-bound vessels transiting the New Panama Canal:
  • Existing Gulf Coast ports. We have already seen that the Gulf Coast ports of Gulfport, New Orleans, Mobile and Houston have maximum berth depths of -45 feet (-14 meters) or less and are unlikely to be deepened to -50 feet (-15 meters). Hence, this option does not address the potential of the large vessel Transshipment Hub.
  • Competing hubs within the Caribbean. Several transshipment hubs exist and have been proposed both in the Caribbean and along the Gulf Coast. Of the major competing hubs within the Caribbean, only Freeport in the Bahamas (dredged depth of -51 feet [-15.5 meters]), the in-process container ports in Colon Panama (dredged depth of -52 feet [-15.8 meters]), and Moín Costa Rica (approach channel dredged to -62 feet [-18.9 meters]) can accommodate the New Panamax vessels. While these ports can function as oceanic transshipment hubs, they cannot serve the needs of U.S. river cabotage which is dominated by non-oceangoing river barges. Also, they will be subject to the Jones Act restriction on foreign flagged vessels engaging in domestic cabotage.
  • Deep water Gulf Coast ports. A floating offshore trans-shipment port complex located about 20 nautical miles (37 kilometers) off the U.S. coasts has been proposed by Lawrence Livermore National Laboratory, in its security research project called If such a complex were to be situated along the approach to the Mississippi River, it could serve as both an oceanic transhipment hub as well as a hub serving large river barges. This terminal would have no draft restrictions but would be orders of magnitude more expensive than a conventional landside port.

An alternative concept

A fourth option has been recently proposed at the mouth of the Mississippi River, called the Louisiana International Gulf Transfer Terminal (LIGTT). As conceived, the LIGTT will be the premier U.S. Gulf Coast cargo gateway to and from America. The LIGTT will effectively address existing and emerging U.S. logistics challenges resulting from fundamental changes in the global shipping industry.

The terminal will specifically address the need for a regional state-of-the-art intermodal container and bulk commodity transfer facility which will be required when the current improvements to the Panama Canal are completed. The LIGTT will not only attract New-Panamax vessels that will be transiting the expanded Panama Canal, it will also accommodate deeper drafting ships that are transiting the Suez Canal as well as those from Latin America and Europe. The terminal will be capable of handling cargo arriving into the United States as well as exporting cargo from the United States to other ports in the world.

The proposed sites

Several sites are proposed for the LIGTT. The near shore site is to be located on more than a thousand acres (more than 400 hectares) of state-owned blue and green field property in the vicinity of River Mile 0 of the Southwest Pass of the Mississippi River directly proximal to the U.S. Gulf Coast shipping lanes. The site is about 20 miles (37 kilometers) south of Venice, Louisiana which is the terminus of Louisiana Highway 23 (LA 23). Located at the lower end of the east bank of Southwest Pass in Plaquemines Parish, the site provides relatively near access to existing water depths of up to -75 feet (-23 meters) and deeper.

The proposed offshore LIGTT site is to be located on several thousand acres of blue field property in the vicinity of River Mile 0 of the Southwest Pass near the three nautical limit line of the state of Louisiana. The water depth will be in excess of -60 feet (-18 meters).

Local and environmental impacts and design considerations

Incorporated into the design, measures must be taken to treat the environment and local communities with respect and to minimize impact to onshore, near shore and offshore environment and local livelihoods such as fishing. In order for the design to target the lowest practical wastes and emissions to air, water and adverse impact to the environment and surrounding communities, measures need to be taken to avoid disruption of environmentally sensitive areas to the extent possible.

The near shore site presents a number of environmental challenges. While it is adjacent to deep water, the amount of dredging required to accommodate the deep drafting vessel is in the millions of cubic yards. Also, the green field portion of the site is tidal and is the habitat of numerous species of flora, fauna and marine organisms.

The site is alongside the federal shipping channel. While this would appear to be a decided advantage, it presents complications. The USACE maintains jetties that jut out into the river from the property’s shore. These jetties are designed to increase the current flow by restricting the channel thus inducing scour which helps to maintain the dredged depth. Siting berths and access structures in this area will alter the river’s hydrodynamic characteristics which have been deemed to be problematic.

Geotechnical challenges also exist. Nearby borings have revealed several hundred feet of soft gray clays interspersed with silt lenses and layers and pockets that include traces of organic matter.

The offshore site alleviates some of these complications. The site selection is based on water depths that will not require dredging. As the site is away from the shore, the issues associated with the tidal wetlands are also avoided. Staying clear of the federal channel eliminates the USACE’s concerns of disruption to the river’s hydrodynamics. However, the site offers a similar geological profile as does the near shore site.

The deeper water invites its own set of challenges. As the water depth increases so does the cost of pile and gravity founded structures. As noted above, floating structures of sufficient magnitude to allow for transshipment are very costly. Furthermore, the float technology envisaged is unproven.

Both sites suffer from annual hurricanes that periodically are classified as Category 4 hurricanes. (When it slammed ashore on the Gulf Coast, Hurricane Katrina was a strong Category 3.) Hurricane Isaac delivered 10 to 12 feet (3 to 3.7 meters) of flood waters in Plaquemines Parish. The storm was very large and slowed down to a crawl once it came ashore. This meant that in addition to the hurricane force winds, the heavy rains off to the east of the storm didn’t let up for days.

The center of the Category 4 Hurricane Ivan, with winds raging up to 150 miles per hour (241 kilometers per hour), passed right over six of the Naval Research Laboratory (NRL) at Stennis Space Center Naval Research Laboratory's wave-tide gauges, churning up waves more than 90 feet (27 meters) high. Bill Teague of the NRL noted that, “There isn't much need to worry about these extreme hurricane waves reaching the shore though. They break up and dissipate when they start feeling the bottom. They don't last that long. They don't travel that far, but they can bust up everything [in their path]."vii

Suffice to say, the terminal design at either site must take into account the forces associated with hurricane induce wind and waves including storm surge in the 20- to 30- foot (6- to 9-meter)range.


Clearly a New Panamax container and commodity transhipment logistics hub port focused on serving the U.S. Gulf Coast and providing major port transhipment gateway services to North America is needed. Intermodal bound containers and bulk cargo shipped through such a hub would be received from various sized international transshipment vessels afloat after passage via the new expanded Panama Canal, from ports across the Atlantic Ocean, or from ports throughout the Western Hemisphere. The LIGTT appears to be a viable option. The challenge is to design a terminal and cargo logistics interface that addresses the issues outline herein while meeting the goals and vision of the developers.


U.S. Port and Inland Waterways Modernization Preparing for Post-Panamax Vessels, U.S. Army Corps of Engineers Institute for Water Resources, June of 2012
ii M-55 Marine Highway Corridor,
iii M-55 Marine Highway Corridor, 
iv The Geography of Transport Systems, Maximum Berth Depth at Major North American Container Ports, Dr. Jean-Paul Rodrigue, Dept. of Global Studies & Geography, Hofstra University,
U.S. Port and Inland Waterways Modernization Preparing for Post-Panamax Vessels, U.S. Army Corps of Engineers Institute for Water Resources, June of 2012
vi Commerce Security from Offshore Port Design, Pacific Maritime Magazine, April 1, 2013
vii Hurricane's Waves Soared to Nearly 100 Feet, Live Science, Bjorn Carey, August 03, 2005