Community-based Waterlogging Disaster Risk Analysis And Management

Flood disaster is one of the major natural disasters in our country, the main flood disaster in Shanghai is rainstorm waterlogging disaster. Community as a basic unit of disaster management, is the direct subject to response disaster risk. Therefore, understanding the community disaster risk, and studying on the community rainstorm waterlogging disaster loss assessment is an important subject. It not only have a great theoretical significance, but also improve the community disaster prevention and mitigation ability, and reduce the casualties and economic loss of disaster.In this paper, the author discusses the urbanization process of the Jiangqiao town, and reveals the land use quantity, structure and degree, whicih influence the exposure and hazard background environment of waterlogging disaster in the the research area 1989 – 2013. Through the investigation of the research area, and the collection of the historical waterlogging disaster data since 1949 of the Jiangqiao Town.Combined with the data of the 2013 "Feite" typhoon, the author analyzes the disaster hazard, exposure, inundation losses and the disaster influence of the study area. Finally, the author refines the waterlogging disaster responding measures of the Jiangqiao community and the future research direction form the results of the disaster analysis and the conclusions of participatory risk assessment.The main conclusions are as following:(1) In 1989-2013, the industrial land, traffic land and residential land of Jiangqiao Town increased to some extent from 1989 to 2013(increase 1683 hectares totally). It is mainly from the reduction of farmland area(reduce 1799 hectares totally, and the total ratio decreased from 67% to 24%). The land use composite index of the Jiangqiao town steadily increased from 316 in 1989 to 357 in 2013, the land utilization rate is high, and belongs to the rapid development stage.(2) Compared to the historical maximum daily rainfall typhoon in 1977, the numbers of the inundated roads, the water flooded residents, the inundation retails and the disaster losses were greatly increased, but the flooded farmland area decreased about 30% in the “Feite” typhoon. The reason is the urbanization process of Jiangqiao town led the agricultural land changes to the traffic land, residential land and commercial land. Thus, the disaster exposure and the disaster background environment change, and led to the frequency and damage loss of the waterlogging disaster increasing.(3) During the “Feite” typhoon, the maximum daily rainfall of the Jiangqiao town is 215.2mm, the annual exceedence probability is 3%. Combined with the precipitation, the surface runoff is 197.98 mm.The author established 3 operation status of the drainage pipe network system to calculate the total volume of stagnant water in the research area during the “Feite” typhoon. When the drainage pipe network system works well, the total volume of stagnant water in the research area is 4697m3; when it works general, the total volume of stagnant water is 5219m3; when it failure, the total volume of stagnant water is 5741m3.On the basis of the digitally generated submerged depth distribution map of the research area, the author calculated the waterlogging loss of the “Feite” typhoon is about 20.85 million, and 92% roads of the research area have 10-56 mm water.(4) In order to deal with the rainstorm waterlogging disaster in research area, the author proposed 6 engineering measures and 7 non-engineering measures. The 6 engineering measures include: the embankment construction and river dredging, underground space transformation, flood control measures of the low-lying residential area, set up the warning signs to easy water points, establishment of the community shelters, and implementation and promotion of the ecological water system. The 7 nonengineering measures are the establishment of community integrated disaster risk management mechanism, strengthen the construction of legal system, improve the risk management of natural disasters disaster insurance system, implementation of community participation in risk management, establishment of community emergency response and disaster risk map, improve the community disaster prevention and mitigation of volunteer team building, training and community disaster disaster drills.