Geospatial approach to local multi-hazard assessment in Malawi: Chikwawa and Nsanje Districts

Abstract

Malawi has experienced a significant increase in the frequency and intensity of disasters in recent years, yet comprehensive risk assessments remain scarce, hindering the development and implementation of evidence-based disaster risk reduction (DRR) and resilience-building policies. This gap persists despite global and regional frameworks underscoring the critical role of risk assessments in informing policy formulation and implementation. The resource-intensive nature and technical complexities of risk assessments have limited their adoption, not only in Malawi but across many developing countries. Chikwawa and Nsanje districts, identified as Malawi’s most disaster-prone and economically vulnerable regions, have been the focus of numerous DRR, humanitarian and resilience-building initiatives by governmental and non-governmental organisations (NGOs). However, the absence of comprehensive risk assessments has resulted in ad hoc program designs and implementations, lacking a robust evidence base to guide their effectiveness. This study employs a geospatial approach, integrating deterministic indicator-based risk assessment methodologies, to systematically assess, quantify and evaluate the implications of multi-hazards in Chikwawa and Nsanje districts. The research aims to enhance disaster risk knowledge, thereby contributing to the formulation and implementation of effective DRR and resilience-building strategies in Malawi. Utilizing the Sustainable Livelihoods Approach (SLA) and the Local Disaster Index (LDI), the study formulates multisectoral socioeconomic indicators to evaluate hazard probabilities, exposure, vulnerability and capacities. The traditional disaster risk notation (R=H*V/C) guides the participatory deterministic risk assessment, while geospatial techniques are employed to analyse the spatial characteristics of these risk factors. Statistical methods are applied to relate hazards and their implications to underlying geophysical factors, enabling the spatial evaluation of hazard probabilities, exposure, and vulnerability across the districts. The study identifies floods, crop pest outbreaks, prolonged dry spells, human disease outbreaksand strong winds or hailstorms as the most prevalent hazards during the rainy season in Chikwawa and Nsanje. The implications of these hazards, both individually and collectively, are assessed, quantified, and spatially mapped. The research reveals that specific geophysical factors significantly influence the spatial distribution of hazard probabilities, exposure and vulnerability, highlighting a disproportionality in capacities across the districts. This disproportionality is attributed to limited evidence-based understanding of the interplay between geophysical factors and disaster risk components. The findings from this study demonstrate that areas characterised by high hazard probabilities, high exposure, high vulnerability and low capacities correspond to elevated disaster risk levels, while areas with low hazard probabilities, low exposure, low vulnerability and high capacities exhibit reduced disaster risk. These patterns are consistent for both single and multiple hazards, with aggregated disaster risk levels calculated using combined probabilities, exposure, vulnerability and capacities. Furthermore, the study highlights the direct impact of floods, crop pest outbreaks, prolonged dry spells and strong winds or hailstorms on land-based livelihoods. By calculating land-risk ratios - derived from aggregated disaster risk levels relative to the proportions of land used for livelihoods - the study identifies areas where high disaster risk coincides with limited livelihood resources, and vice versa. The findings from this study demonstrate that areas characterised by high hazard probabilities, high exposure, high vulnerability and low capacities correspond to elevated disaster risk levels, while areas with low hazard probabilities, low exposure, low vulnerability and high capacities exhibit reduced disaster risk. These patterns are consistent for both single and multiple hazards, with aggregated disaster risk levels calculated using combined probabilities, exposure, vulnerability and capacities. Furthermore, the study highlights the direct impact of floods, crop pest outbreaks, prolonged dry spells and strong winds or hailstorms on land-based livelihoods. By calculating land-risk ratios - derived from aggregated disaster risk levels relative to the proportions of land used for livelihoods - the study identifies areas where high disaster risk coincides with limited livelihood resources, and vice versa.