长江上游洪涝灾害分析及防灾减灾措施

分析了长江上游洪水和渍涝灾害的发生频率、危害程度和演变趋势。在季风环流和山区地形抬升作用下，形成长江上游４个年雨量大于２０００ｍｍ的暴雨中心，使盆周和乌江上游成为雨洪多发区，各大江河汇合口普遍存在洪泛之害。夏季山洪、秋季雨涝、沿江洪水淹没和山区泥石流等水害频繁，且灾害的发生频率和造成的损失有继续增大的趋势，通过对历史灾情的分析，提出了洪涝频率和面积分布。洪涝灾害的危害程度既受天气异常的影响，又与人类活动密切相关。长江上游的防洪抗灾应采取因地制宜、综合治理的方针，即结合大型水库控制、水土保持、农田水利、灾害预警和社会保险等措施消减灾害，其中尤以长江上游防护林和大江河干流水库枢纽作用巨大，可起到削蓄洪水、涵养水源、减少侵蚀和改善生态环境条件的综合功效，是带根本性的流域治理措施。

THE ANALYSIS OF FLOOD AND WATER LOGGING DISASTERS AT THE UPPER BASIN OF THE CHANGJIANG RIVER AND THEIR MEASURES

This paper analyses the flood and waterlogging disasters, their occurrence, damages and changing tendencies for the upper basin of Changjiang River. Under the effects of monsoon and orographic blocking, there are four storm centers in the area with annual precipitation more than 2000 mm. Heavy storms happened frequently in upper Wujiang River and around Sichuan Basin. there is also the risk of flood inundation along river banks. The common types of disasters are flashing flood in summer, water logging in autumn, flood inundation on flood plains and debrisflow in mountainous areas. The losses of disaster depend not only on the extent of weather change, but also on the human activity. In order to reduce the disasters of flood and waterlogging, multi measures should be taken for different area and different situation, that is, combining the approaches of reservoir storage, water soil conservation, farmland irrigation, flood warning and social insurance systems. Among them the large scale reservoirs on the main rivers and the protective forest systems in upper basin of Changjiang River will take the key parts. They can store runoff, reduce flood risk, conserve water resources, increase lowflow and improve the quality of eco environment, and constitute the fundamental measures for watershed harnessing.