Floodways are accepted as economic and environment-friendly alternative road infrastructure to bridges and culverts in rural road networks with low traffic volumes. They play a vital role to the economy of a country by connecting regional communities, farm lands and agricultural areas to city centres. However, floodways are subjected to a certain degree of submergence from their design aspects and hence differ from other road infrastructures. Nevertheless, natural hazards can cause damage to floodways as evident from the 2011 and 2013 Queensland flood events. Fifty-eight per cent of floodway structures in the Lockyer Valley Regional Council area in Queensland were damaged during the 2013 Queensland flood event leading to operational failures in rural road networks and the isolation of regional communities.

Damage assessment during the post-disaster event is a difficult but important step to enhance the resilience of regional communities. A lack of proper methodology to estimate the extent of damage can cause huge delays to repair/reconstruction activities and also can lead to errors in making correct decisions and prioritising the repair/reconstruction works. Such delays can be detrimental to the resilience of the regional communities. This paper develops a quantitative method to estimate the extent of the damage using a damage index method. Failures in upstream, downstream and road way zones and their extent of damage are examined and evaluated across a number of floodways in the Lockyer Valley Regional Council area to develop a generalised method. The analysis is performed based on the cost estimations at elementary level for the floodways damaged in the 2013 flood event. This method will quickly and accurately estimate the extent of the damage to enable correct decisions to be made and prioritised regarding repair/reconstruction works. This approach, therefore, enhances the resilience of regional communities who are served by floodways.