The North American Waterway System

Port locations and sites are preliminary constrained by the quality of maritime access they can provide. A core component of this access is related to the depth of the waterway system and of access channels in particular. The North American continent, unlike its European counterpart, is not very prone to inland waterway distribution and is composed of three major subsystems:

• The Eastern Seaboard, with the exception of the St. Lawrence / Great Lakes system, offers no significant navigable river system as the Appalachian Mountains are just a few hundred kilometers from the coast. The upper Great Lakes (Erie, Huron, Michigan and Superior) offer good navigation depths, but navigation is limited by the waterways between the lakes and by ice in winter. Further, access to the Atlantic is limited to the depth and lock size of the St. Lawrence Seaway, which is closed for a few months during the winter. The St. Lawrence enables to go deep inland, but maritime vessels can go up to Montreal, which is essentially at the same longitude than New York. The Eastern Seaboard however has a complex but underused coastal transport system. The Intracoastal Waterway services most of the Eastern Seaboard and consists of a series of bays, inlets, sounds and artificial canals.
• For the Gulf of Mexico, the Mississippi inland waterway system is extensive but limited to depths of less than 20 feet. Under such circumstances, ports along the Mississippi are dominantly handling barges loaded with agricultural commodities, which implies a highly seasonal traffic. Additionally, the Mississippi system has a north-south orientation while most of the goods flows are east-west, implying a limited potential to service intermodal freight movements. Like the Eastern Seaboard, there is an Intracoastal Waterway ranging from Texas to Florida.
• The Western Seaboard has four major deep water gateways, Seattle, Portland, San Francisco and Los Angeles but poor waterway access to the interior because of the Sierra Nevada and Rockies. The only exception is the Columbia River basin which is accessible to deep-sea ships up to Portland which is about 160 km inland.