地理学与自然灾害杂志
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Application of Flood Frequency Analysis to Examine Spatiotemporal Households Flood Vulnerability in Karonga District and Lilongwe City, Malawi

Isaac Kadono Mwalwimba1*, Mtafu Manda2, Cosmo Ngongondo3

Flood Frequency Analysis (FFA) is an important component of flood risk mitigation and preparedness. It shows where floods might happen, and provides vulnerability data needed for response and preparedness. However, in developing countries like Malawi, there are limited studies that integrate FFA to understand the spatiotemporal characteristics in flood risk analysis. This informed the need to undertake this study in rural areas of Traditional Authority (T/A) Kilupula in Karonga District (KD) and Mtandire Ward in Lilongwe City (LC). The study utilized hydrological streamflow, Geographical Information System (GIS), and disaster profile data for the Lufilya and Lingadzi catchments in KD and LC respectively. Baseline data was collected from the Departments of Water Resources and Disaster Management Affairs in the Ministries of Water and Sanitation and Natural Resources and Climate Change respectively. Statistical methods and ArcGIS 10.8 were used to analyze data. The results found a higher expected flood for Lingadzi compared to Lufilya catchments in LC and KD respectively at different return periods. Spatiotemporal characteristics such as increased volume of water in the channels due to short lag time resulting from sealing of land surface and loss of agricultural land due to changes in river channels, human occupancy along the river channels and poor catchment management contribute to high household flood vulnerability. This study provides a basis for integrating FFA into FVA (Flood Vulnerable Areas) in any region in the world because all the input data is globally available.