Geographical Analysis as Determination of Flood Risk Area

Flood map-making that produced by BNPB was delineated by four disaster management components: hazard, vulnerability, capacity, and risk. Flood map making is one of non-structural strategy in prevention/mitigation phase to reduce flood risk. In this study, we took flood prone area as our case study. We analyzed and compared the correlation between flood map and flood data history. However, flood factor has important role in flood process, both natural and human factors. We analyzed a case study based on the geographical condition: terrain and surface runoff. We believed that the often flood hazard area is the riskier area. Risk in disaster management is related to hazard, vulnerability, and capacity of area. It also related to amount of damage and loss, which is in economic matter. In this study, flood risk was not calculated in loss number, but determination flood risk area. Risk area in our concern is area that first flooding attack. The purpose of this study is to determine flood risk area, based on terrain and surface runoff. We analyzed and assessed the correlation of flood map and flood history in the last few years. Then, we used several maps and software as methodological tools. Sketch Up and AutoCAD were used to delineate flood inundation and flood risk area. HEC-HMS is used to calculate runoff volume of each land use. This study found that flooding first attack would impact to farming land use in north part, paddy field in west part, and east part of Napai. We delineated in four level risk areas. Flood inundation in farming area gives loss in economy and livelihood. However, flooding occurs in residential and public facility area give other ‘risk’ to human living. Research expecting result is to contribute giving information to government and stakeholder in flood disaster management strategies. By categorized flood risk area in detail, preparedness and mitigation strategies, damage and loss will be decreasing in the next flooding, also community do not have to evacuate every flooding come.