Identification of element at risk due to tidal flood hazard in Genuk Sub-District coastal area

Abstract

The coastal area is a meeting point and a transition zone between land and sea. The morphology of the coastal areas, which is relatively flat and rich in the quality and quantity of natural resources makes the coastal area become centre of population growth. Population growth in coastal areas occurs rapidly and accompanied by potential coastal hazards alongside. Population growth is one factor that many elements at risk will be affected. The Semarang-Demak coastal area, especially at the downstream of Babon River, Genuk Sub-District, experienced the potential of tidal flood. The purposes of this study are to examine the distribution of element at risk due to tidal flood hazards. This research employed satellite image data processing and field surveys methods. First, the research analyzed tidal flood hazard using ArcGIS software and map algebra with a raster calculation tool. Second, it elaborated several elements at risk in the research area. The result of the study showed that the flood hazard index resulted in the distribution of areas affected by tidal floods covering the areas of Terboyo Kulon, Terboyo Wetan, Trimulyo, Banjardowo and Muktiharjo Lor. The largest area which affected by the tidal floods is in the Trimulyo Village (176.820 Ha with the number of hazard index 0.2; 185,364 Ha at the hazard index 0.4; 195,931 Ha at the hazard index 0.6; 205,393 Ha at the hazard index 0.8; and 210,361 Ha on the hazard index 1). While the smallest area which affected by the tidal floods is in Banjardowo and Muktiharjo Lor Sub-Districts. Then the research area the most exposed element at risk are population and its built-up environment, while active productive agriculture land also prominent.