Normalized Difference Drought Index (NDDI) computation for mapping drought severity in Bojonegoro Regency, East Java, Indonesia

Abstract

Abstract Drought is a natural disaster that causes difficulties meeting household, agriculture, and industrial water needs. Drought often occurs in various regions in Indonesia, one of which is the Bojonegoro Regency. Bojonegoro Regency has the highest number of villages experiencing drought in East Java Province in 2019. This study aims to map the drought severity in the Bojonegoro Regency based on the results of the Normalized Difference Drought Index (NDDI) computation. The method used to obtain NDDI was by subtracting the Normalized Difference Vegetation Index (NDVI) by the Normalized Difference Water Index (NDWI) and then dividing by the NDVI plus the NDWI. The results showed five drought severity classes in Bojonegoro Regency: very low, low, medium, high, and very high. Areas classified as high and very high severity have an area of 1,534.32 (0.66%) and 99.38 ha (0.04%), respectively. These results indicate that many areas have the potential to experience drought in Bojonegoro Regency. The results of this analysis can be an input to the government to carry out mitigation efforts such as building reservoirs and infiltration wells, preserving the karst area, and increasing the vegetation cover against drought disasters in the future.