Approximating Delays at Interdependent Locks

As with much of the nation's infrastructure, the inland waterway system is in critical need of expansion and repair. Many of the inland waterway lock and dam facilities have become major constraints to navigation due to increased traffic and facility deterioration, leading to costly delays. Because funds for lock and dam improvements are severely limited, comprehensive analysis methods are necessary to ensure efficient allocation of resources among the many proposed improvement projects. Unfortunately, locks and dams are often treated as independent facilities with regard to operations when in fact there are likely to be significant interdependencies among many of them. An analysis technique is needed that accounts for interdependencies between locks when considering lock improvements. In this paper, a method is developed whereby the delays of a set of interdependent locks may be calculated. By incorporating interdependencies into benefit calculations of lock-improvement projects, a more comprehensive assessment of improvement priorities can be established.