From the thesis abstract: "This thesis develops an Operator's Model that mimics the real-world behavior of coal transport in the Port of Pittsburgh and allows for systematic investigation of 'what if' disruption scenarios. We model the multi-modal flow of coal using a network of nodes and arcs representing river transport, with support from a surrounding system of rail lines and roads. Each mode of shipment has finite capacities with varying costs. Our model routes flows in order to satisfy contracted supplies and demands at minimum transportation cost. We use 2009 coal shipment data provided by the United States Army Corps of Engineers to drive delivery patterns. We focus our attention on the Monongahela River, which carries a significant amount of coal through our system. We employ Defender-Attacker-Defender techniques to assess critical infrastructure in the context of an intelligent adversary, such as a terrorist, who seeks to damage the system so as to maximally increase its operating cost. This allows us to assess the relative importance of critical system components in order to help the United Stated Coast Guard identify where to focus their attention."