Risk Assessment Of Urban Rainstorm Disaster

Rainstorm disaster occurs frequently in the summer.Waterlogging resulting from heavy rainfall often leads to great loss in urban system.Beijing-Tianjin-Hebei is the crucial part of Huabei region and risk assessment of rainstorm acts the significant role in disaster prevention and mitigation.In this paper,based on daily precipitation from 1960 to 2014,digital elevation model and demographic and economic statistics,spatiotemporal characteristics and probability distribution of extreme precipitation have been studied,and vulnerability curve of indoor property has been constructed.Using an integrated approach with fuzzy theory and Monte Carlo simulation,uncertainty analysis and risk zoning of Beijing-Tianjin-Hebei have also been conducted.Main findings and conclusions are as follows.Precipitation of north-west part of the region is high in amount and intensity and low in frequency,while precipitation of south-east part is low in amount and intensity and high in frequency.Heavy rainfall greater than 50 mm distributed in the similar spatial pattern.Positive anomalies of rainstorm amount and intensity have been enlarged with the process of urbanization.Meanwhile,extreme precipitation sequences conformed to the generalized extreme value distribution.To establish the vulnerability curve,indoor properties of families with different level of income have been classified and valued on the basis of their market prices and penetration rates.A new fitting form has been applied to study the relationship between water depth and loss ratio,after which the vulnerability curve was accordingly plotted.Fuzzy theory and Monte Carlo simulation were employed to build the fuzzy-Monte Carlo model of rainstorm risk assessment.Thus risk zoning maps of Beijing-Tianjin-Hebei have been obtained along with uncertainty analysis.The result of rainstorm risk assessment is of great importance in science and application to emergency management and disaster mitigation.