GIS AND REMOTE SENSING BASED FLOOD RISK MAPPING AND VULNERABILITY ASSESSMENT: A CASE STUDY OF T/A PEMBA IN SALIMA

Floods are among the most destructive natural hazards in Malawi, and rural areas like Traditional Authority (T/A) Pemba in Salima District are particularly susceptible due to low elevation, high rainfall, and settlements situated near river networks. Despite the frequency of these events, disaster risk management often relies on broad-scale data, creating a need for detailed, community-level spatial assessments. This study assessed flood risk and community socio-economic vulnerability in T/A Pemba using Geographic Information Systems (GIS) and remote sensing. A mixed-methods research design was employed to integrate spatial analysis with socio-economic data. Physical flood risk was modeled using environmental variables, including elevation, slope, rainfall intensity, land use and land cover (LULC), flow accumulation, and distance to rivers. Socio-economic vulnerability was assessed through household surveys, evaluating indicators such as income level, education, livelihood type, household size, housing condition, and access to services. The Analytic Hierarchy Process (AHP) was utilized to determine the relative weights of these parameters. The integration of these components, weighted at 75.0% for physical risk and 25.0% for socio-economic vulnerability, reveals a highly uneven spatial distribution of susceptibility. The results indicate that 77.1% of T/A Pemba falls within high or moderate susceptibility zones, primarily driven by proximity to river networks and widespread socio-economic constraints. Furthermore, 14.5% of the area is classified as very high susceptibility, representing critical spatial intersections where extreme socio-economic vulnerability overlaps with high physical flood exposure. In contrast, low susceptibility zones cover only 8.4% of the area. These findings demonstrate that while physical exposure dictates the spatial extent of flood hazards, community resilience is heavily constrained by socio economic factors. The localized flood risk and vulnerability maps generated in this study provide actionable spatial data to support targeted mitigation measures, early warning systems, and resource allocation, directly aligning with Malawi Vision 2063, the Disaster Risk Management Bill (2023), and the Sendai Framework for Disaster Risk Reduction.

Floods are among the most destructive natural hazards in Malawi, and rural areas like Traditional Authority (T/A) Pemba in Salima District are particularly susceptible due to low elevation, high rainfall, and settlements situated near river networks. Physical flood risk was modeled using environmental variables, including elevation, slope, rainfall intensity, land use and land cover (LULC), flow accumulation, and distance to rivers. The results indicate that 77.1% of T/A Pemba falls within high or moderate susceptibility zones, primarily driven by proximity to river networks and widespread socio-economic constraints. The localized flood risk and vulnerability maps generated in this study provide actionable spatial data to support targeted mitigation measures, early warning systems, and resource allocation, directly aligning with Malawi Vision 2063, the Disaster Risk Management Bill (2023), and the Sendai Framework for Disaster Risk Reduction.

The study was conducted in Traditional Authority Pemba located in Salima District in the central region of Malawi as shown in Figure 2. The area lies within the lakeshore zone and is characterized by relatively low-lying terrain and the presence of seasonal rivers that drain into Lake Malawi. These geographical characteristics increase the susceptibility of the area to flooding, particularly during periods of intense rainfall. Flood events in the area frequently result in damage to infrastructure, destruction of agricultural land, and disruption of socio-economic activities within local communities. The majority of households in TA Pemba depend on subsistence agriculture and fishing as their primary sources of livelihood. These livelihood activities are highly sensitive to climate variability and hydrological hazards such as floods. Settlements located near river channels and low lying areas are particularly exposed to flood hazards. Due to the frequency of flood events and the vulnerability of local communities, TA Pemba provides an appropriate setting for assessing flood risk and vulnerability using Geographic Information Systems (GIS) and remote sensing techniques.

Traditional authority: TA Pemba

District: Salima

Coordinates: -13.863, 34.5222