Determination of Coastal Belt in the Area Prone to Disaster (The Coastal area of Bantul Regency - Yogyakarta Special Province)

The mitigation strategy development is needed for protecting coastal communities and preserving coastal resources from the impact of coastal hazards. Reducing impact from coastal hazards, it is believed that coastal land use planning can be proposed. An inexpensive solution if be compared with hard structure development, the coastal belt boundary development is one of the mitigation approach which is common use in many country. To develop coastal belt boundary, ideally, the use of coastal hazard and process is required to ensure a save and sustainable approach by minimizing the exposure of people, socioeconomic activities and infrastructures to natural disasters. However, the prochedure to calculate the coastal belt boundary was not clearly defined in Indonesia. In this study, a new method for determining coastal belt boundary was developed. The Spatial Multi Criteria Evaluation (SMCE) tool of Ilwis plays as powerful tool for assessing coastal vulnerability in term of multi-hazard events. To calculate the width of the coastal belt boundary, the Ilwis-SMCE outcomes were employed. By applying this method, there were three scenarios of the setbacks wide for both direct and pairwise method to be proposed. Our study was located in the coastal area of Bantul regency, a low lying coastal area and densely populated region, where clustered people live proximity to the sea. Threatened mainly by high waves, coastal erosion accretion as well as tsunami, the coastal vulnerability in term of those hazards was reconstructed. Incorporating multi-level input data, there were two scales of planning employed, namely macro and micro scale. In general, the coastal area of Bantul Regency is dominated by high vulnerable area respectively impacted by multi-hazard events (tsunami, high wave and erosion-accretion), by incorporating some coastal features, such as topography, bio-physics, economic, and socialculture. The results of the analysis are consistent with what was observed in the actual areas. Taken into account for hazard and vulnerability indices, the coastal belt boundary proposed in this area should wider than those already established by existing regulations