Establishing the Wildland-Urban interface building risk index (WUIBRI): The case study of Beit-Meri

Dwellers experience a constant threat of wildfires when constructing their residences in woodland settings in or near forests. In these regions, also recognized as Wildland-Urban Interface (WUI), consequences of wildfires can be fatal to humans, animals and vegetation. The establishment of wildfire risk indexes is useful when produced on a community scale; these indexes proved their effectiveness worldwide to identify vulnerabilities to ignition and fire spread, to understand the underlying science and to simulate exposure. In this paper, four main inputs (i.e. wildfire likelihood, defensible space, building envelope, and community infrastructure) are used to produce the WUI Building Risk Index (WUIBRI), representing the wildfire likelihood at the property-level, in a typical WUI area, namely, Beit-Meri - Lebanon. Results show that one fourth of the total buildings have an undesirable WUIBRI value - greater than eight, demanding fast response and effective mitigation techniques. This index illustrates a weak positive spatial autocorrelation in the study area, which measures dependency among sub-regions, and no relationship with the buildings' prices. A Cost-Benefit Analysis (CBA) is conducted and projected over the next five years from the date of the study. Under the conservative scenario, output reveals that implementing simple measures (i.e. pruning and trimming vegetation around the home, creating two-ways roads with two exits, establishing fire sprinklers system) reduces WUIBRI values; accordingly, decreasing the wildfire threat would require only 20% on the first year and 6.15% on the long run (for the next five years) of the total costs when only one wildfire occurs per year. It is recommended that homeowners, municipalities, and decision-makers, join forces to create a fire-adapted community. The approach outlined in this study is achievable in other Mediterranean regions to reduce wildfire suppression costs.