长江荆江分蓄洪区历史演变、前景和风险管理

Historic evolution perspective and flood risk management of the Jingjiang Flood Diversion District in the Yangtze River Basin

依据社会经济统计数据、水文资料、遥感影像信息和实地调查资料,分析了荆江分蓄洪区在历史演变过程中形成的分洪与发展的矛盾及其在未来长江流域防洪体系中的重要作用,指出其风险管理的必要性。运用基于G IS栅格数据的二维水动力洪水动态演进模型,对荆江分蓄洪区1954年的分洪过程进行了模拟和验证,模拟了不同分洪规划方案下的洪水淹没范围,水深和水位,并结合现阶段社会经济发展情况,定量估算了农户和农业的分洪可能损失。在分洪损失评估基础上提出了荆江分蓄洪区引导人口合理发展、促进土地有效利用、开展防洪教育、实施洪水保险和确保安全运用预案等减轻洪水损失提高运用机率的洪水风险管理初步方案。

Applying the social and economic statistical materials, hydrological data, remote sensing images and field investigation information, evolution of the Jingjiang flood diversion district is discussed to show the contradictory status quo of the flood diversion district and its irrevocable position in the future flood protection system of the Yangtze River. Furthermore, necessity of flood risk management is emphasized. Two dimensional GIS raster based dynamic flood risk estimation model is introduced and used for the present study to simulate the flooding process of Jingjiang flood diversion district during the floods of year 1954. Based on different simulation results of three hydrographs representing low, medium and high inflow rate, the potential losses of inundation are estimated. Accordingly, some flood risks management strategies are put forward with the purpose of flood losses mitigation and utilization probability increment, including population policy, regulation of land use pattern, strengthening of public awareness, development of flood insurance, and planning of scientific flood diversion schemes etc.