Quantitative assessment of disaster loss caused by rainstorms and floods in Guangdong

Rainstorms in Guangdong have the characteristics of high intensity, wide range and long season, causing severe flood disasters and great impacts. In order to make rational and quantitative assessment on the intensity and loss caused by rainstorms and floods in Guangdong, a comprehensive intensity assessment model and disaster index model were constructed and proposed in this study, based on analysis of the rainstorm events and their corresponding loss data in Guangdong from 1994 to 2018. By using the 60^th, 80^th, 90^th and 95^th percentiles as critical thresholds, the rainstorm events were classified into five categories, namely, Ⅰ (week), Ⅱ (relatively week), Ⅲ (medium), Ⅳ (relatively strong), and Ⅴ (strong) according to their intensity. They were also categorized as micro disaster, small disaster, medium disaster, major disaster, and catastrophe according to their severity in terms of disaster loss. The possible losses of population, crops, houses and economy caused by rainstorm events of different categories were then analyzed. The results indicated that: (1) During 1994-2018, the rainstorm events with different categories in Guangdong mainly occurred in the flood season, i.e. from April to September, especially from May to July. (2) The intensity of the rainstorm events had a significant positive correlation with the disaster index of various hazard-bearing bodies. With increasing intensity of the rainstorm events, the number of collapsed houses increased exponentially, while the number of people affected, the number of deaths, affected areas of crops and direct economic losses all increased linearly. (3) When the intensity of the rainstorm events reached up to category Ⅴ (strong), the averaged values of the number of people affected, the number of deaths, affected areas of crops, the number of collapsed houses and direct economic losses are 1 871 900 people, 22 people, 105 200 hectares, 112 thousand rooms and 1.307 billion Yuan, respectively.