Corps Needs More Locks Study

March 6, 2001

The U.S. Army Corps of Engineers should explore other options for managing barge traffic before it considers extending the length of several locks on the Upper Mississippi River-Illinois Waterway system, says a new report from the National Academies' National Research Council. Lock extensions could cost about $1 billion, would disrupt waterway traffic during years of construction, and may damage the surrounding environment. Instead, the report urges that other, nonstructural alternatives be considered carefully before moving forward.

The report examines a feasibility study that the Corps began in 1989 to determine the economic viability and environmental implications of extending locks. To date, the study has cost more than $50 million. When controversies arose early in 2000 over the economic analyses being used by the Corps, the U.S. Army asked the National Academies to convene an expert committee to review the study. The committee's findings and recommendations are based on draft documents prepared as part of the feasibility study. The Corps announced in September that its final report would not be ready in the immediate future.

"Although the Corps has made important improvements in its analysis, it apparently considered lock extensions as the only means to reduce congestion, ignoring a range of less expensive options that wouldn't require rebuilding locks and dams," said committee chair Lester Lave, the Harry B. and James H. Higgins Professor of Economics, and University Professor, Carnegie Mellon University, Pittsburgh. "We're recommending not going down that track until nonstructural alternatives have been examined closely. We hope our advice will help the Corps strengthen and improve its analysis of a difficult problem as it works to complete the feasibility study."

By nonstructural alternatives, the committee is referring to relatively inexpensive options such as improved scheduling of traffic passing through the locks and better equipment for hooking barges together faster. One way of improving scheduling would be to issue permits to pass through locks at specified times, with the added flexibility of allowing the permits to be traded among towboat captains.

More than 120 million tons of cargo destined for international markets -- much of it corn and soybeans -- are shipped each year along the river through a system of 29 locks and dams that span hundreds of miles. Many of the locks are at least 60 years old and were originally designed for "tows" of barges of up to 600 feet in length. But as commerce has grown over time, the length of a typical tow has doubled and congestion has increased. If barge traffic were distributed more evenly, congestion would decrease and shipping costs would fall.

The Corps made a major improvement in its cost-benefit analyses by adopting a theoretical model that considers alternative modes of transportation and destinations for products shipped on inland waterways, the committee said. However, in applying the model to grain shipments, the Corps simplified it so that, in fact, it did not consider destinations other than the port of New Orleans or other uses for the grain. Since grain may be exported via other ports, or could be used in domestic food products or animal feed, the Corps would be overestimating demand for use of the waterway by focusing solely on barges carrying grain to New Orleans.

Model forecasts of grain shipments 50 years into the future also were flawed. For example, they predicted increases in grain exports between 1995 and 2000, when in fact, export levels remained steady or dropped slightly during this time. Further inaccuracies resulted from the Corps relying on assumptions rather than actual data for key components of the models. And the price data that were used to estimate demand for barge services were inappropriate.

To determine whether the costly waterway project is in the public interest, the Corps should obtain accurate data on crop shipments by barge and other modes of transportation that includes information on the quantity being shipped, where it originated, and its destination, the committee said. Supply and demand should be analyzed using current crop prices and actual prices for all modes of transport. The cost of gathering data is small relative to other study costs, especially compared to the economic and environmental costs of making an incorrect decision to extend, or not extend, the locks.

The Corps also should recognize the inherent uncertainty of predicting barge shipments years into the future, the committee added. Instead of setting precise values for future demand for barge movements, the Corps' feasibility study should comment on a range of values and conditions under which the benefits of lock extensions would exceed the costs.

Once they are more accurate, the Corps' economic analyses should be integrated with the environmental aspects of the feasibility study to offer a more comprehensive assessment of the effects of proposed options, the committee said. As the Corps study stands now, efforts at integrating economic and environmental components are inadequate. For example, the study fails to describe how environmental changes would affect the multibillion-dollar tourist and recreational economies that depend on an ecologically healthy river. And although the Corps has conducted dozens of environmental investigations, it is unclear how findings from this research are incorporated into the decision-making process regarding proposed lock extensions.

To further integrate environmental assessments into its study, the Corps should adopt the principles of adaptive management, the committee said. This approach is gaining currency within the natural-resources management community because it enables managers to adapt decisions to changing situations -- such as varying water levels -- and to make ongoing adjustments. Adaptive management also places environmental and social considerations on par with economic ones. The Corps' draft documents describe an adaptive mitigation strategy that the committee deemed insufficient. Since the environmental effects of additional barge traffic and lock construction are not precisely known, the extent to which these effects might be mitigated also is not known.

Despite the numerous environmental assessments carried out by the Corps, several gaps remain in the scientific understanding of how dams, locks, towboats, and barges have affected the river, in addition to how future changes may affect it. The committee therefore recommended that Congress provide funding for other federal and state agencies to join the Corps in studies of the navigation system's current environmental effects on the waterway. Congress also should require the Corps to have its environmental and lock-extension studies reviewed by an interdisciplinary group of outside experts, the committee said.