上海洪涝灾害发生特征、致灾因子及影响机制研究

Characteristics,cause factors and influence mechanism of flood and water logging in Shanghai

基于上海1949-1991年间洪涝灾害发生频次和程度数据,综合考虑城市化和区域环境变化对洪涝灾害的可能影响,系统探讨了研究时期内上海洪涝灾害发生的基本特征和趋势性。选取汛期降雨量、米市渡和黄浦公园年最高潮位以及逐年河道消失数作为主要致灾因子,分析了它们对上海洪涝灾害发生的影响程度和方式。研究表明,选取时段内上海洪涝灾害发生频率有下降趋势,灾害程度趋于减轻;水利工程对洪涝灾害的发生具有决定性的影响。致灾因子自身变化与城市化进程及其区域环境变化有一定的响应关系,其致使洪涝灾害发生的作用方式呈阶段性变化。降水和潮位的致灾影响基本是即时性的,河道消失的致灾影响则具有滞后性和持续性。多元回归分析表明,采用米市渡年最高潮位、年河道消失数和汛期雨量指标,可以进行洪涝灾害发生的趋势性预测。

Based on the data including flood frequency, flood season rainfall, maximum tidal level and number of disappeared rivers during 1949 - 1991, considered the comprehensive affection of urbanization and regional envi- ronmental change on flood occurrence, this paper approaches the characteristics and change regulations of flood oc- currence and flood-causing factors in Shanghai. The results showed that there have a downward trend of the flood frequency and an alleviatory trend of the flood extent in selected period in Shanghai. Flood control engineering effi- ciently decrease the occurrence and effect of floods. Changes of flood-causing factors well respond to the process of urbanization and regional environmental change. The flood causing way of each factor is different, rainfall and tidal level would affect flood occurrence and extent instantly and the impact of river disappearance on flood would lag 2 - 3 year and last for 4 -5 years. Multiple regression analysis shows that the frequency trend of floods could be predicted by indicators of annual maximum tidal Level in Mishidu Station, the annual number of river disappearance and the flood season rainfall.