Risk Assessment of Flood-Prone Roads Using Digital Models

Abstract

Climate change and extreme weather events constitute a major threat to the integrity and the operability of every transportation system. Storm surges, wildfires, floods and hurricanes may produce unforeseeable damage to passengers, vehicles, goods and roads Among these climate hazards, floods are the most damaging and hard to confront. With respect to traffic and the road infrastructure, devastating floods are observed every year all over the globe, inundating roadways, ruining bridges and causing fatalities. At international level, the concern about flood risk has gradually been amplified and respective action plans have been elaborated and implemented in Europe and elsewhere. It seems, however, that these action plans are hardly sufficient to prevent road flooding.On a scale of a region or a town, it is very important to identify proactively the safest road corridors, as well as those of uncertain operability under flood conditions. By contrast to the general methods proposed by most research institutions and associations, what is really needed is the assessment of the submersion risk for the road/street network by segment and of the effectiveness of some proactive measures, either of current practice or totally innovative. In this regard, low-cost engineering operations over unsafe road corridors, such as profile uplift, drilled wells, lateral protection boards or additional drainage systems, may prove beneficial, once these low-level segments are identified. The dual digital concept may prove very effective in the fight against roadway inundation and traffic blockage. The concept consists of two digital models, the digital testing model and the digital twin model and is meant for Road Operators willing to safeguard the infrastructure and to protect travelers. It consists of a digital flood-testing model and a digital twin model. The digital flood-testing model makes possible a virtual inundation of the road corridor and the surroundings by rainfall water over a return period of >250 years. Every proactive measure or set of measures against flooding, to be potentially taken, can thus be tested proactively using this model and the respective outcome, in terms of flood impact alleviation, can be assessed. The digital twin model is an interactive tool providing real-time information, in case of flood. It observes constantly and evaluates the rate of the water level rise and forecasts eventual emergency situation by means of these digital tools, Road Operators can identify the most vulnerable and the safest Road Corridors, as well as to spot low-lying and flood-prone road segments along Critical Corridors. Accordingly, they will be able to plan actions to upgrade and reinforce the deficient infrastructure but also to elaborate suitable emergency plans in order to effectively face aggressive events of extreme severity. The paper presents the layout of this dual digital concept and some measures to upgrade low-lying road segments by conventional as well as by innovative techniques.