Study On Water System Connectivity Evaluation Based On Graph Theory Research In Jiaodong Area

As the development of Chinese economy and society, lake water network connectivitypatterns have taken place great changes in the process of natural evolution and humandevelopment and lake water systems connectivity problem have caused wide spread concernin the community in recent years. This study based on the theory of edge connectivity ofgraph theory, through analyzing the characteristics of the river water systems construction andassociating water transfer engineering and river ecological restoration and rivers drainageconnected in the modern water network at home and abroad, put forward a set of quantitativeevaluation method of the application of graph theory that is proposed for watershed scalesof lake water system connections.So as to improve the regional water environment and waterecology and risk analysis of water supply and water resources optimal allocation andscheduling provides basic theoretical foundation.This dissertation analyzes the quantitative oflacustrine water network connectivity and on the risk of water supply under different waterdiversion project, take Jiaodong for instance.To sum up, the research mainly includes thefollowing aspects:(1)Through analyzing the basic situation of Jiaodong region river system, provide databasis with the evaluation of the connection of lake water systems for Jiaodong area,mainlyWeihai and Yantai.Including geography, hydrology and meteorology, social economy andwater resources and current situation of the development and utilization of rivers.(2)This section mainly introduces the concepts of connectivity of graph theory and itsapplication.At the same time,using graph adjacency matrix of the graph obtains theconnectivity discriminant criterion.According to the analysis of different figure connecteddegree, draw a graph edge connectivityλ (G)which means that nontrivial graph into adisconnected graph must remove the minimum number of edges.As a result, we can make useof edge connectivity to measure a nontrivial graph of connected degree and make aquantitative analysis of the degree of connected graph.(3)Using the close cooperation relations of GIS and graph theory in computing theshortest path problem, analyze the water network connectivity with quantitative evaluationmethod and construct the connectedness of lake water system flow chart of evaluation method.In data preparation stage, through getting the river system in the study area map (based on the vector topographic maps of the Rushan river as an example)to understand different regionrivers water drainage in the connected degree.The process of source file using ArcGISplatform to generate digital elevation model DEM, then load the DEM and extract thedistribution of drainage basin.According to the theory of graph connectivity,micro-geomorphic units such as the drainage system of lakes, lake water channel and gate dam aregeneralized with graph. Then constructing adjacency matrix and using MATLAB to calculateprogram, draw water system flow chart of connectivity analysis method of lakes.(4)According to the water network connectivity evaluation method, make an effectanalysis of the modern water network connectivity as a research case of Jiaodong area.Themodern water network of the evaluation index system, this section choose flood control anddrought relief, water and water environment to establish evaluation index system of a waternetwork.According to the overall planning principles of Shandong water networks, analyzewater network connectivity respectively under original state, Yellow River Jiqing andJiaodong water diversion project, then generalize graph model and calculate itsconnectivity.Take Weihai, Yantai and Pingdu for instance, using the single index of watershortage carry out risk analysis of water supply under different connectivity in Jiaodong area.(5)Integration of water transfer project and water deficit, make an analysis ofcomprehensive risk of water supply and obtain the risk analysis of water table in Jiaodongregion.It can be found that engineering design often been obtained using the probability isvery low under the present situation of connectivity recent years, while water diversion worksusing probability increase gradually with the increase of two-year extension and waterdemand, need diversion project to increase its connectivity to reduce their risk of water supplythrough comprehensive analysis.It does not mean that the more diversion project, the larger ofthe connectivity and the smaller of the risk of water supply, it also need to consider thebenefits of water supply.Therefore, it is with the index of water, water ecological index, floodcontrol and drought index to format a modern water index system under the effect ofconnectivity evaluation, to provide the reasonable allocation and optimize the scheduling ofwater resources with theory analysis.