Assessment Of The Effectiveness Of Water System Connectivity In The Comprehensive Urban Water System Management Project

The rapid development of urbanization leads to an increase in the impermeability of land substrate and cuts the natural river network water pattern,resulting in insufficient flood control capacity of the original rivers and frequent deterioration of the water environment,which becomes the first resistance to restrict the healthy and sustainable development of society.Comprehensive urban water environment management project can enhance the connectivity of regional rivers,lakes and water systems,improve the regional water environment and water ecological conditions to a certain extent,enhance the water disaster prevention capacity,and help realize the harmony between people and water.The scientific evaluation of the water system connectivity effect of the comprehensive urban water system management project and the analysis of the impact of the comprehensive water system management project on the morphological characteristics,hydrological characteristics,ecological environment improvement and social service benefits of the water system can provide a theoretical basis for further water system connectivity effect enhancement and the development of the management plan.Based on PSR("Pressure-Problem-Response")theory,the thesis analyzes the improvement situation of water system connectivity projects in the study area,and combines relevant research results at home and abroad to build an index system for evaluating the effectiveness of water system connectivity of regional urban water system comprehensive management projects based on the criteria of structural connectivity,hydraulic connectivity,ecological and environmental benefits and socioeconomic benefits.Based on ArcGIS digital elevation and remote sensing image data extraction,the SWMM urban flooding simulation process and river hydrodynamic simulation model were established;the coupled model was used to simulate the flow rate,flow velocity,point source pollution attenuation and flooding distribution under different working conditions of the comprehensive urban water system management project in Runan County,and the evaluation system of water system connectivity effect for the constructed comprehensive urban water system management project was developed.The results of the evaluation showed that: the urban water system comprehensive management project is a good example.The evaluation results show that the implementation of the comprehensive urban water system management project has improved the water system connectivity effect to excellent;68.98% of the rivers in the region are revitalized compared with the pre-water system connectivity,the number of regional river frequency increased by 93.33% from 0.15/km2 to 0.29/km2,plus the overall increase of 58.11% in the urban water surface rate of newly excavated lakes,the total water area increased by 57.51%,the density of the river network increased by4.55%;the improved connectivity between the river network increased the water exchange capacity by 37.5% and the flow speed by 30%;the decay rate of point source pollution increased by 40.61%,the river water quality basically reached the V standard,and the green area coverage increased to 32.29%.The flood control benefits reduced by the water system connectivity project at P=50a amounted to 65.87%,the landscape benefits were calculated to be 14.8698 million yuan,the water supply benefit enhancement effect was 1.1%,and the net tourism benefit enhancement was 5.23%.