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Flood vulnerability assessment of the 2010 event, using participatory mapping tools and modeling in Yingxiu Town, China

Ramos, Beatriz Lao (2012) Flood vulnerability assessment of the 2010 event, using participatory mapping tools and modeling in Yingxiu Town, China.

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Abstract:Flooding has been recognized as one of the most important disasters worldwide by the number of persons killed, the number of victims and economic damages. In China, millions of victims associated to this phenomenon in 1998 places this country as the top of countries affected mostly (Guha Sapir et al., 2011). Also, in 2010 it was the combination of floods and landslides associated to heavy monsoon rains that caused millions of victims in southern China (Guha Sapir, et al., 2011). Yingxiu, a town located in this region was affected as well. However, detailed studies on flooding in this area were not developed. In order to minimize the impacts of future flood, an effective flood risk assessment is required. In this approach, community knowledge is combined with research methods for the assessment of the 2010 flood event, the damage and vulnerability assessment, and the risk reduction option as a stage of flood risk management. The 2010 flooding is reconstructed using local knowledge and modeling methods. Participatory mapping tools such as participatory GIS, sketch mapping, focus group discussion, and transect mapping were used to capture experiences, perception and coping mechanisms related to this event. Characteristics of the 2010 flood event: extension, water depth on measurements points, and duration were obtained applying this method. Ground height values were obtained through fieldwork measurements and the DEM was improved. Values of water depth for all buildings were calculated. Another characteristic such as velocity was obtained during modeling process applying SOBEK 2D software. Results were combined during the assessment of the 2010 flood event. Community knowledge and fieldwork observation were used in the identification of elements at risk, as well as in the determination of direct and indirect damage. Economic losses values were given on macro scale level. On the other hand, physical and social vulnerability assessments were developed as well. Vulnerability matrices that reflect the flood-vulnerability relationship between water depth, velocity and damage scale (DS) for structural buildings were built based on methods proposed by Kelman (2002). Social vulnerability was based on the integration of social indicators applying Spatial Multi Criteria Evaluation (SMCE). Finally, community perception and coping mechanisms related to the 2010 flood event were analyzed and measures to contribute to the minimization of flood risks are proposed. The study concluded that the flooded area is located along the right bank of the Minjiang River, occupying an area that around 76.0 km2. Maximum values of water depth (>5.0 m) and velocity (>4.0 m/s) were located in the northern part of the town. The most damaged buildings were building structural type_1 and type_2 located in this area, subjected to high values of water depth and velocity during four flooding days. These buildings correspond to the highest value of physical vulnerability. On the other hand, in the households with high values of the social vulnerability were found children and elderly people, population with low and very low income and two or more persons with the primary educational level. In general, the contribution of this event to the annual risk exceeded 10 million of Yuan (1.3 million of Euros). Keywords: Flood Event Assessment, Damage Assessment, Vulnerability Assessment, Risk Reduction Option, Participatory Mapping Tools, Yingxiu Town.
Item Type:Essay (Master)
Faculty:ITC: Faculty of Geo-information Science and Earth Observation
Programme:Geoinformation Science and Earth Observation MSc (75014)
Link to this item:https://purl.utwente.nl/essays/93412
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