福建省山洪灾害风险识别与定量分析

受极端天气、复杂下垫面和人类活动多重因素影响,山洪灾害在我国频发高发,且预测预报难度较大。本文基于全国山洪灾害调查评价成果,着眼于15-20 km~2的小流域,从降雨、下垫面、社会经济、现状防洪能力、涉水工程及监测预警设施配置率6个方面,提取了54个备选指标,运用主成分分析法进行降维处理,筛选了10个核心且独立的指标,构建了风险评估指标体系,建立了风险立方体模型,并运用福建省2306场历史山洪场次数据进行了模型验证。结果表明,基于小流域的山洪灾害风险识别可有效反映灾害对降雨和下垫面的响应关系;沿海台风暴雨高发区和内陆山区短时强降雨高值区是山洪灾害高风险区,涉及小流域1151个,面积近2万km~2,人口608万。

Flash flood risk identification and quantitative analysis: a case study in Fujian province

Under the influence of extreme weather, complex underlying surface and human activities, flash flood disasters occur frequently in China and are very difficult to predict. Based on national flash flood disaster investigation and assessment results, this article focused on 15-20 km² watershed level, from the aspects of rainfall,underlying surface,social and economic situation,flood control capacity,wading engineering and monitoring early warning facilities, first extracted 54 alternative indicators, using principal component analysis (PCA), and then, obtained 10 independent indexes to build flash flood risk index system, and finally, established risk cube model with 2306 historical flash disaster events in Fujian province for model validation. The results showed that flash flood risk identification based on small watershed can effectively reflect the response relationship between rainfall and underlying surface caused by disasters, and in Fujian Province, coastal typhoon and storm flooding areas and short duration heavy rainfall inland hilly areas are flash flood disaster high-risk areas, involving 1151 small basins, with an area of 20,000 km² and a population of 6.08 million. The results provided sufficient data support and played an important role in improving the accuracy of flash flood forecasting and early warning in Fujian province.