  Natural disasters are highly complex and unpredictable. However, long-term
planning and preparedness activities can help to mitigate the consequences and
reduce the damage. For example, in cities with a high risk of flooding,
appropriate roadway mitigation can help reduce the impact of floods or high
waters on transportation systems. Such communities could benefit from a
comprehensive assessment of mitigation on road networks and identification of
the best subset of roads to mitigate. In this study, we address a pre-disaster
planning problem that seeks to strengthen a road network against flooding. We
develop a network design problem that maximizes the improvement in
accessibility and travel times between population centers and healthcare
facilities subject to a given budget. We provide techniques for reducing the
problem size to help make the problem tractable. We use cities in the state of
Iowa in our computational experiments.
