Study On The Relationship Between Hongze Lake And Huaihe River And Its Storage Capacity

Flood control in the middle and lower reaches of the Huaihe River is one of the key points of flood control in the Huaihe River Basin,and flood control in the Hongze Lake area has always been a difficult point in flood control in the middle and lower reaches of the Huaihe River.The relationship between rivers and lakes is the key factor affecting flood control in the middle and lower reaches of the Huaihe River.Correct understanding of the relationship between rivers and lakes and handling the relationship between rivers and lakes is the key to flood control in the Huaihe River Basin.Based on this,this paper compares the characteristics of river-lake relationship between Huaihe River and Hongze Lake with other similar rivers and lakes,systematically expounds the connotation of river-lake relationship between Huaihe River and Hongze Lake,and studies the driving factors of relationship between rivers and lakes,the interannual variation trend of water and sediment discharge into and out of Hongze lake,and the regulation capacity of Hongze Lake.The main contents and results of this paper are as follows:(1)The relationship between the rivers and lakes of the Huaihe River and Hongze Lake is systematically studied.It is proposed that the river-lake relationship between the Huaihe River and Hongze Lake is driven by water and sand exchange,serving the flood control in the middle and lower reaches of the Huaihe River,in the form of the evolution of rivers,lakes and deltas,the change of the storage capacity of Hongze Lake and the evolution and discharge capacity of the outlet of the lake.At the same time,summarizes the historical research and evolution process of the relationship between rivers and lakes,and analyzes the current situation of the relationship between rivers and lakes.On this basis,the research trend of river-lake relationship is further forecasted.It is believed that the study of river-lake relationship needs to establish more theoretical and technical conditions.(2)Based on the measured annual runoff and annual sediment transport data from 1975 to 2015 of the hydrological stations on behalf of the tributaries of Hongze Lake,the water distribution and sediment distribution characteristics of the Hongze Lake were analyzed.Mann-Kendall(M-K)rank correlation test and Pettitt mutation point identification method are used to study the interannual variation trend of water and sediment volume in and out of the lake and the possible year of mutation.On this basis,the main influencing factors of water and sediment change in Hongze Lake are analyzed from three aspects:rainfall,water resources development and utilization,and sediment detention in upstream reservoirs.The results show that the interannual variation trend of water inflow and outflow from Hongze Lake is the same,and there is no obvious decreasing trend and no significant mutation point.The sediment inflow tends to decrease slightly,and the M-K statistic value of sediment outflow exceeds 95%significant level,which shows a significant decreasing trend.The year of abrupt change of sediment volume in and out of lakes is 1991.Through the analysis of the influencing factors,it is concluded that the change of rainfall is an important influencing factor of the change of water inflow into the lake.The water inflow into the lake shows no obvious decreasing trend after 1993,which is related to the obvious increase of water consumption in the basin and the improvement of water resources development and utilization.The change of sediment volume in Hongze Lake is mainly affected by sediment detention in upstream reservoirs.Because of the continuous siltation of sediment in Hongze Lake,the trend of sediment discharge from the lake is relatively obvious.(3)The flood control situation and current flood control capacity in the middle and lower reaches of the Huaihe River are analyzed.The flood regulation process of Hongze Lake is sorted out.The flood regulation function of Hongze Lake is divided into storage function and regulation function.Based on the data of rainstorm and flood in 1991,2003 and 2007,the storage capacity of Hongze Lake is analyzed.Hongze Lake's primary flood regulation and storage volume has little change,which is about 3 billion m~3,showing an increasing trend.Based on the fact that the storage capacity of Hongze Lake can not fully express the storage function of the lake,a parameter,the regulation coefficient,which can more accurately express the storage function of the lake to the flood is proposed.The flood regulation coefficient of Hongze Lake increased from 0.19 to 0.21 to 0.38,indicating that the flood storage effect of Hongze Lake was gradually enhanced.The regulation effect of Hongze Lake on high-lean and low-fat floods is obviously different,and the regulation effect of Hongze Lake on low-lean floods is stronger.It is pointed out that the discharge capacity of outflow channel is also a part of the storage capacity of Hongze Lake,and the application of artificial channel plays an important role in flood control.Sediment deposition and artificial reclamation are the decisive factors affecting the change of storage capacity of Hongze Lake.The results provide theoretical guidance and technical support for the analysis of the storage capacity of Hongze Lake.