Loading...
3 results
Search Results
Now showing 1 - 3 of 3
- Assessing wildfire exposure and social vulnerability at the local scale using a GIS-based approachPublication . Gonçalves, Ana; Oliveira, Sandra; Zêzere, JoséExposure and vulnerability analysis are valuable tools for wildfire management, especially important for local communities that suffer from very destructive events and that require mitigation approaches adjusted to their abilities and needs. We present a methodological procedure to analyze wildfire exposure levels, social vulnerability conditions and coping capacity at the local scale, for villages or small human settlements. The procedure was developed using GIS (Geographic Information Systems) and programming tools in R and Python, which can be adapted and updated depending on the data available. The development of accessible procedures and easily replicable methodologies facilitates knowledge transfer and supports the application of mitigation and adaptation strategies, tailored to the conditions of the exposed areas. • A step-by-step procedure for the assessment of Exposure, Vulnerability, and Coping Capacity, using Python and R programming language. • Automated processes, easily replicable and adjustable to other areas. • Indications for adapting the methodology using European/international databases.
- Defining priorities for wildfire mitigation actions at the local scale: insights from a novel risk analysis method applied in PortugalPublication . Benali, Akli; Aparício, Bruno A.; Gonçalves, Ana; Oliveira, SandraIntroduction: In Portugal, the 2017 fire season was particularly extreme, leading to an unprecedented large number of fatalities, injured people, destruction of houses and infrastructures. These dramatic outcomes have contributed to raise awareness regarding the importance of ensuring the safety of people and assets from high intensity uncontrollable wildfires. It is crucial to identify the settlements at higher risk and the most suitable mitigation actions that can maximize the protection of people and assets. Methods: We developed a simple methodology that combines exposure and vulnerability to estimate wildfire risk at the local level. Exposure was estimated using a fire spread simulation approach that was used to determine the probability of (i) a wildfire generating firebrands that could affect a settlement and (ii) a high intensity wildfire occurring adjacent to a settlement. Exposure was estimated using two fuel scenarios created to represent the current year of 2023 (short-term scenario) and 2030, assuming that no fuel management nor large fires occur in the meantime (medium-term worst-case scenario). Vulnerability was determined by the (i) Index of Total Dependence (IDT), and (ii) evacuation difficulty. Exposure and vulnerability metrics were normalized in percentiles, distributed into quadrants and combined to provide six levels of wildfire risk. For each vulnerability\exposure combination, we proposed a set of priority mitigation actions. The methodology was applied to three areas in Portugal where the risk estimates were analyzed and compared with the implementation rate of two risk mitigation programs already in place. Results: Results showed that 8.7% of the settlements had “very high” wildfire risk and about 19.5% had “high” wildfire risk, potentially affecting 8,403 and 34,762 inhabitants, respectively. The spatial distribution of settlements at higher risk was very heterogeneous across the study areas and the total fraction ranged between 14% in Coimbra to 36% in Barlavento Algarvio. The overall implementation of mitigation programs in the study areas is very low, with only around 1% of the settlements in “very high” risk having any of the mitigation programs implemented. Conversely, our results also suggest that the implementation rate in settlements classified in lower risk classes is disproportionately high. Discussion: The application of this risk analysis methodology can be used to assess the implementation status of mitigation actions, and contribute to tailor the actions that maximize the protection of people and assets according to the specific conditions found in each targeted area.
- Assessing risk and prioritizing safety interventions in human settlements affected by large wildfiresPublication . Oliveira, Sandra; Gonçalves, Ana; Benali, Akli; Sá, Ana; Zêzere, José; Pereira, José MiguelThe large wildfires of June 2017 disturbed many communities in central Portugal. The civil parish of Alvares was severely affected, with about 60% of its area burnt. Assessing the risk of large wildfires affecting local communities is becoming increasingly important, to reduce potential losses in the future. In this study, we assessed wildfire risk for the 36 villages of Alvares parish, by combining hazard, exposure and vulnerability analysis at the settlement scale. Hazard was obtained from fire spread simulations, which integrated exposure together with population and building density within each village. Vulnerability was based on the sociodemographic characteristics of the population, ranked with a hierarchical cluster analysis. Coping capacity was also integrated, considering the distance of each village to the fire station and the time needed for residents to reach a shelter. We simulated 12 different land management scenarios, regarding the implementation of a fuel-break network and the level of forest management activities. The potential effects of each scenario in the exposure and risk levels of the settlements were evaluated. The results show that, for a business-as-usual scenario, 36% of the villages are at high or very high risk of wildfires. Examining each risk component, 28% of the villages are highly exposed, 44% are highly vulnerable, and 22% do not have a potential shelter on-site, calling for different intervention strategies in each specific risk dimension. All the land management scenarios, even if designed for other purposes than the protection of settlements, could decrease the proportion of highly exposed villages at different levels, up to a maximum of 61%. These findings can contribute to adjust prevention and mitigation strategies to the risk levels and the characteristics of the population and the territory, and to prioritize the protection and emergency actions at the local scale.