赣江尾闾河网地形变化对洪季水动力的影响北大核心CSCD

为探明在新水沙条件和人类活动的影响下赣江尾闾河网地形变化与洪季水动力特征变化的关系,以1998—2020年为研究时段,基于1998、2013、2020年河道地形,分别建立一维河网数学模型,复演赣江98特大洪水,研究不同时期地形变化对洪季水动力特征的影响。结果表明:赣江尾闾河网的整体下切使水位流量关系右移,洪期各支洪峰流量整体增加,相同水位下,外洲站来流增幅超过50%。1998—2020年期间,南支地形下切幅度大于其他各支,地形不均匀下切导致尾闾河网节点分流比改变,整体上主支与南支分流增多、中支与北支分流减少。各支流速变化剧烈,主支下游流速增幅超过1 m/s。本研究可为河道整治规划、堤坝防护和灾害预防提供一些技术参考。

Effects of topographic changes in terminal river network of Ganjiang River on its hydrodynamics in flood season

This paper is to explore the relationship between the topographic changes of Ganjiang River network and the changes in its hydrodynamics in flood season under the influence of new water and sediment conditions and human activities. We developed one-dimensional river network mathematical models during 1998-2020 based on the river topographic changes in 1998, 2013 and 2020 respectively to simulate the 1998 flood in this river. The influence of topographic changes in different periods on hydrodynamic characteristics in flood season is studied. The results show that in this river network, the overall downcutting has caused the water level-discharge relationship to shift to the right, and the flood peak discharges in each branch increases, with an inflow increase of more than 50% under the same water level. During 1998-2020, the southern branch had a topographic downcutting depth greater than the other branches, and its uneven topographic downcutting resulted in a change in the distributary ratios at the river network nodes. On the whole, the distributary flow increased in the main branch and the southern branch, while it decreased in the middle and northern branches. Flow velocity in each branch changed dramatically, with an increase of more than 1 m/s in the downstream section of the main branch. This study is useful for river regulation planning, dam protection, and disaster prevention.