Remote Sensing and GIS Based Agricultural Drought Risk Assessment in East Shewa Zone, Central Rift Valley Region of Ethiopia

摘要

Drought is one of the most complex naturally occurring disasters that results in serious human life, environmental, social and economic costs around the world. In order to monitor agricultural drought risk, GIS and remote sensing have a significant role. This research was conducted in East Shewa Zone of Oromia Region of Ethiopia with the objective of mapping agricultural drought risk using GIS and remote sensing. Ten years decadal SPOT NDVI datasets were downloaded from VITO website. In order to compute the Standardized Precipitation Index (SPI), rainfall data was obtained from meteorological stations of the study area. The result of drought severity index indicated that 2005 and 2009 were years of drought while 2013 identified as wet year. On the other hand based the result of SPI, 2005 and 2009 were years of droughts while 2012 wet year. The result also showed that there is good correlation (r = 0.7) between long term NDVI and seasonal rainfalls. The results were supported by the interviews and focus group discussions. Based on the result drought risk map, 5.1% of the zone are under extreme drought risk, 31.9% severe drought, 27.1% moderate drought and 32.5% are under mild drought. Thus, it is only the remaining 3% of the East Shewa Zone that are not vulnerable to drought. Our findings showed that we can use GIS and remote sensing for drought assessment in regions where there are scarce ground observation data. Future research may focus on camparson of ground observation data and sattellite derived data.