Holistic and Practical Approach for Assessing Flood Risks of Low Volume Asphalt Roads

Flood-induced damage to roadways is well recognized and documented in local and national media as well as in the literature. However, the damage to pavement structures that remain visually intact after a flood event are far from well understood, nor is there a guideline for selecting an appropriate engineering tool or procedure to evaluate such structural damage, based on flood characteristics and roadway conditions. While low volume roads are the most vulnerable to flood-induced damage, many municipalities, such as smaller cities, towns, or local government districts, are the least prepared to address such risks and hazards to their transportation infrastructure because of the lack of financial or technical resources. A holistic framework for assessing flood damage after a flood event or for future flood scenarios is proposed, which considers destructiveness of hazard (i.e., flood), vulnerability, and consequence of the flood. A quantitative, composite indicator, risk factor ( RF), as a multiplication of hazard destructiveness factor ( HF), vulnerability factor ( VF), and consequence factor ( CF), can readily be approximated with flood characteristics, pavement characteristics, and functional class of pavement and traffic volume. A flooding risk map is then developed, on the basis of the RF in a space of physical damage factor ( PF)–consequence factor ( CF). The map is divided into three different risk zones: high risk zone ( RF>64), medium risk zone (27< RF≤64), and low risk zone ( RF≤27). The proposed holistic, quantitative approach has been applied to six flooded pavement sections in Louisiana to evaluate its feasibility and application potential.