The identification of flood susceptibility and its contributing factors in Sampang Regency

Abstract

Sampang Regency is susceptible to flood which caused by river overflow due to rainfall peak period and rising seawater. Kamoning watershed is one of an area that got annual overflow flood. While the coastal area of Sampang Regency faces rising-seawater flood/high-tide flooding. This research aimed to map the flood susceptibility class in Sampang Regency using a morphological approach. Remote sensing and GIS analysis was used to classify the area into three flood susceptibility classes: high, moderate, and low. After that, the map is verified using hydrostratigraphy analysis using the geoelectric Schlumberger method. Based on the identification, 6 villages in 9 subdistricts located alongside the Kamoning River have a high flood susceptibility owing to river overflow. On the other hand, rising seawater is causing floods in Sreseh Sub-District, Jrengik Sub-District, Pangarengan Sub-District, Sampang Sub-District and Camplong Sub-District in the southern part of Sampang Regency, whereas Banyuates Sub-District, Ketapang Sub-District and Sokobanah Sub-District in the northern part. Consequently, those areas are also classified as high flood susceptibility areas. The hydrostratigraphy analysis showed that the surface of Sampang Regency is mainly composed of clay. With low permeability level (0.0002 m/day), water pools and surface runoff could easily be generated when rain falls.