Drought vulnerability assessment using geospatial technologies: A case of Borana zone, Oromiya National Regional State, Ethiopia

Abstract

Drought is the dryness due to an acute shortage of water, which lasts for several months or years. The present study aims at analyzing drought vulnerability using Geospatial technologies in case of Borena Zone, Oromiya National Regional State, Ethiopia. Time series satellite data of MODIS vegetation and ten years, CHRIPS rainfall data (2010 to 2020) was used to assess drought vulnerability in the study area. Drought vulnerability assessment were analyzed using drought indices like normalized difference vegetation index (NDVI), vegetation condition index (VCI), drought severity index (DSI), and meteorological indices like standardized precipitation-evapotranspiration index (SPEI), standardized precipitation index (SPI), precipitation concentration index (PCI). In the present study, 16 meteorological stations rainfall and temperature data were used for validation purpose. The correlation between observed rainfall and vegetation indices reveals that there is a positive relationship between the rainfall and NDVI (R2= 0.4996), VCI and rainfall (R² = 0.409) and SPI and rainfall (R² = 0.917). The final vulnerability map of the study area reveals that the area as mild vulnerable, moderate vulnerable, severe and extremely vulnerable. Accordingly, most part of south eastern and northern, some parts of the western and central areas are extremely vulnerable. At district level, Arero, Miyo, Moyale, Dehas, Yabello, Melka soda, Bulehora, and Gelana are severely vulnerable to drought. Teltele, Dire, and Abaya are moderately vulnerable, with some portions of the Abaya district categorized as extremely vulnerable. Small parts of Dillo and Teltele districts were among the regions that were mildly susceptible. In general, about 450 hectares is extremely vulnerable 31086 hectare is severely vulnerable and 6933 hectares moderately vulnerable and 1100 hectares are mild vulnerable. For further understanding of drought condition of the study area; increasing the availability of data for all meteorological stations with the required temporal coverage and precision is crucial, some type of data like evapotranspiration at national level is highly needed. Federal disaster prevention and preparedness commission have to be prepared for upcoming drought disaster for the area’s delineated as extreme and severely vulnerable to drought. The reason why this study conducted in this study area is that; this area was suffering from extreme events.