Evolution Characteristics Of River Network Of The Three Estuaries Of Southern Jing River And Their Impacts On Storage Capacity

The construction of various water conservancy projects and the acceleration of urbanization process in the three estuaries of southern Jing river.A large number of rivers have been invaded and the river network structure has deviated from its natural development rules under the strong intervention of humans.The variation between the evolution of the river network and the storage capacity in the three estuaries of southern Jing river are urgently needed to be analyzed.The results of its analysis are of great significance for the enhancement of the storage capacity and the realization of sustainable economic and social development.The main research contents and results are as follows:1.Using-the five times river network maps of the three estuaries of southern:Jing river(1955,1978,1990,2008,and 2016),the river network density,surface water rate,river network complexity,tributary development coefficient,and fractal dimension Change characteristics are quantitative analyzed.The results showed that the river length,number,river network density,and surface rate of the three estuaries of southern Jing river were all decreasing.The water surface and river network density in Huarong River decreased the most,the water surface rate decreased by 4.21%,and the river network density decreased by 0.25km/km2.The developmental coefficient of the tributaries and the complexity of the river network decreased significantly;the fractal dimension of the river network also showed a downward trend,of which the Huarong River had the largest decrease from 1.646 to 1.421.2.From the aspects of hydrological connectivity change,connectivity morphology change,and connectivity morphology,the changes of the river network connectivity in the study area were analyzed.The results show that the hydrological connectivity of the region shows a downward trend,but the change is not significant.In 2016,compared with 1955,the degree of connectivity a,node connection ratio ?,and river network connectivity y decreased by 45.45%,10.8%,and 8.46%,respectively,and the node connection ratio ?decreased most significantly.The two water system connectivity assessment methods based on the river network connectivity(E)of the natural social function of the river network and based on the flow resistance and the hydrological process(F),the changes of the river network connectivity in the three estuaries of southern Jing river were analyzed.Two results showed that the river network connectivity in the study area was declining from 0.2367 and 0.3434 to 0.1588 and 0.2517.3.The paper selected three representative water level stations in the study area(Xinjiangkou,Mituo Temple,and Guanjiapu Station),using river network storage capacity(C),variable storage capacity(AC),unit area storage capacity(SR),and units area adjustable storage capacity(ASR)is the four indicators that characterize the river network capacity.The results show that:In the past 61 years,the river network capacity of the study area has been continuously declining,C has decreased by 26.17%,AC has decreased by 47.59%,'and there has been a difference in the storage capacity of different hierarchical rivers.The reduction of 4th and 5th level rivers Relatively weak,the storage capacity of the lth,2th,and 3th level rivers decreased most obviously;the C,AC,SR,and ASR of each river network zone in the study area showed a declining trend.Among them,the Ouchi River river network area had the largest reduction extent.It decreased by 23.73%,34.6%,28.72%and 41.15%.The data of river network structure,connectivity,storage capacity,and adjustable storage capacity for the five periods of Songzi River,Hudu River and Dianchi River were selected for Pearson correlation analysis.The results showed that the capacity of the river network regulation,hydrological connectivity,and surface water rate,Fractal dimension,river network connectivity degree(a),river network connectivity(y),river network connectivity E,and river network connectivity F were significantly positively correlated at 0.01 level.Therefore,on the one hand,lakes and river system connectivity projects will be implemented to optimize the structure of the river network.On the other hand,the existing watercourses will be protected,rectifying the rivers,ensuring the water surface rate,dredging and widening the river channels,and improving the storage ability of the river network.