| Due to the special conditions of nature,economy and society,and long-term affected by the the Yellow River,the flood disaster in the Huaihe River Basin is serious,the water is complicated,and the management is difficult.After the flood in 1991,the State Council successively established the 19 and 38 major projects of the Huaihe River.However,the current engineering measures of the Huaihe River have not completely eradicated the flood disaster of the Huaihe River,especially in the middle and lower reaches,the problem of closing the flood is still serious.Therefore,the research on the effect of regulation of the main stream of the Huaihe River has important guiding significance for the planning,design and construction of the new round of Huaihe River project.This paper fully combines the river channel regulation and flood disaster background of the Huaihe River,and relies on the national key project of “Watercourse Remediation and Mainstream Flood Evolution” of Huaihe River to study the effects of river remediation and different remediation schemes on floods.The main results are as follows:(1)Based on the measured data,the variation law of flood propagation before and after river improvement projects is analyzed.The research shows that the flood propagation time of each river section is shortened to some extent after the river course is remediated,and the water level-flow rope curve shows a right shift,and the flow increases at the same level,and the water level in the same level of flow has a different degree of reduction.(2)The hydrodynamic mathematical model from Wangjiaba to Xiaoliuxiang section of the Huaihe River main stream was established,and the model was validated and verified.The simulation results agree well with the measured values,providing a calculation platform for the evaluation of the changes of flood propagation law before and after river improvement projects and the influence effect evaluation of flood evolution.Then the model is used to analyze the change law of flood propagation before and after river improvement projects.The results show that the flow at the same water level increases after the river course is remediated,and the water level at the same flow decreases to some extent,which is consistent with the analysis results of the measured data.At the same time,the flow increase and water level decrease in the middle and lower reaches gradually decrease,indicating that the flood channel in the middle and lower reaches has not been fully opened,and further improvement projects is needed.The model is also used to analyze the impact of river improvement projects on the flood evolution process and the risk of dyke collapse.It shows that the existing improvement projects projects can effectively reduce the water level along the river course,shorten the flood propagation time,improve the drainage capacity of the beach trough,and reduce the risk of dike breakout.(3)Selecting the key and difficult river sections of the middle reaches of the Huaihe River,the Zhengyangguan-Wujiadu section,designing different river improvement schemes,using the model to simulate the river flood evolution,and analyzing the water level along the river,water surface ratio,the relationship between water level and flow,flood evolution process and discharge capacity under different improvement schemes,and comprehensively analyze the effects of different improvement schemes on hydrological situation,river stability,water conservancy projects,flood control and rescue and residents along the river.The research shows that the dredging project is the main one,and the scheme supplemented by the flood control area adjusting is the best.The scheme has positive significance for improving the river stability,ensuring flood control safety and promoting economic development along the river. |
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