Traffic on both the Upper Mississippi River and the Illinois Waterway (UMR-IWW) steadily increased after the completion of the lock and dam navigation system.

Traffic usage and tonnage increased rapidly through the 1970s. Although tonnage increased substantially on the UMR-IWW from the 1940s when the 9-foot channel became operational through the 1970s, growth rates flattened between the 1980s and the mid 2000s. Since then, tonnage has trended downward.

Traffic increased by a factor of 8 between 1950 and 1980. Between 1965 and 2002, commercial traffic increased by an annual average growth rate of 2.2 percent for the Upper Mississippi River reach, and 1.2 percent for the Illinois Waterway reach. Traffic is greatest at the downstream end of the navigation system as different regions add or consume commodities in the downstream or upstream direction, respectively.

The flattening and downward trend of tonnage on the UMR-IWW has paralleled a number of other occurrences that may have had some influence – congestion on the system increased with usage; railways became much more efficient following deregulation in 1980 and competed aggressively for freight; agricultural export decreased for some of the period; high ocean shipping rates made shipping by rail to the West Coast competitive with river shipping to the Gulf; and numerous floods since 1993 have caused the locks to close for extended periods of time during the shipping season. In addition, corn is being used for the production of ethanol, decreasing the amount available for export.

There are indications that traffic on the UMR-IWW will resume upward growth in the future, provided investment in Inland Waterways makes it a desirable option. At present there are more than 580 manufacturing facilities, terminals, grain elevators, and docks on the Upper Mississippi River and Illinois Waterway that ship and receive numerous commodities, including grain, chemicals, petroleum products, coal, cement, non-metallic minerals, metallic and paper products, and scrap.

Increasing freight demand will impact all modes, including waterways. This will lead to additional delays on the Navigation System adversely impacting the national economy. Rails’ easy gains in productivity following deregulation have largely played out; West (and East Coast) ports and vicinities are growing more and more congested with the increase in population and international trade; and Panama is moving ahead with expansion of the Panama Canal, which may lead to more freight moving through Gulf ports and more direct transit to Asian markets from the Gulf. In addition, roadway congestion may lead to more high-valued freight moving to rail, which may have a secondary shift of lower valued freight to waterways. However, forecasting and transportation models do not allow for a multimodal analysis of these possibilities.

With the present high rate of lock use, increased traffic on the current navigation system is expected to create excessive congestion and delays, safety problems, and possible adverse environmental affects.