ANALYSIS OF FLOOD-AFFECTED AREAS DUE TO EXTREME WEATHER IN PACITAN, INDONESIA

Abstract

Extreme weather events such as tropical cyclones trigger floods in parts of Indonesia and result
in massive damage. Tropical Cyclone Cempaka in 2017 is an example of such an event, which caused high
levels of loss of life and property in Pacitan Regency. This area is located in the southern part of Java Island,
an area prone to tropical cyclones. This paper aims to identify the specific area of Pacitan, Indonesia, that is
affected to flood hazards triggered by extreme weather. The flood event during Cyclone Cempaka in 2017 is
used as a case study, and the identification of flood-affected areas due to extreme weather was carried out by
an analysis of Landsat 8 satellite imagery. Normalized Differentiation Vegetation Index (NDVI) was used to
identify the inundated areas at that time, corrected by Normalized Difference Water Index (NDWI), slope, and
landform. The flood-affected area included 11 villages with a total area of 412.684 hectares. Those villages are
located in areas of landform resulting from fluvial processes with slope 0-2 and 2-7% which are prone to
flooding. The results of the identification are appropriate for preparing mitigation strategies for the area.