Standardized Precipitation Index (SPI)-Based Flood and Drought Hotspot Mapping in Niger, West Africa

Abstract

Niger is a Sahelian territory in West Africa, with a surface area of 1,267,000 km². Most of it is desert, sparsely populated, or uninhabitable, with a low population density of around 18 inhabitants per km². The adverse effects of climate change and the frequency and intensity of natural disasters are increasing, while the country is evolving in a context characterised by a lack of and/or limited access to detailed, reliable, and up-to-date data, useful for better risk and disaster management. The methodological approach was based on the use of the agroecological map of Niger offering four main zones (Sudanian, agropastoral, pastoral and desert), the calculation and projection on this map of the Standardized Precipitation Index (SPI) of 3935 localities based on the rainfall proxy data series (1979-2035), and then the identification of zones impacted by extreme climatic events. The populations impacted in these identified areas are estimated by projecting onto these areas the updated population of more than 36,000 georeferenced localities in ReNaLoc. The result of this approach shows that it is possible to opportunely identify zones and collect key data for use in the disaster risk management process in the context of a country where data is difficult to acquire. Keyword: Floods, Droughts, SPI, Extreme event, Risk Management Parameter, Characterisation, Impact, Niger.