Construction And Application Of Blue-Green Spatial Fusion Degree Evaluation System

As the main object of urban ecological network construction,blue-green space is the key to building a sustainable,resilient and strong adaptive urban ecosystem.Its construction quality directly affects the urban ecological livable environment and ecological construction,and many studies have shown that blue-green space has good ecological,economic and social benefits.However,in urban planning and reconstruction,the phenomenon of separate construction of water banks often occurs,resulting in many problems such as blue-green fractures,water bank segmentation,etc.,which seriously destroys the connectivity of urban water green corridors,greatly affects the local biodiversity and the integrity of the ecosystem,inhibits the construction of urban blue-green integration,and seriously restricts the construction and quality of urban ecological livable environment.Many studies have shown that the blue-green space has good ecological,economic and social benefits,but the current research is to evaluate the water body and green space,without considering the planning coordination and the integration of the urban ecosystem,lacking reliable and comprehensive indicators as the basic basis,and unable to evaluate the spatial structure and ecological function of the blue-green integration with the appropriate indicator system.Shanghai is located at the estuary of the lower reaches of the Yangtze River,with typical water system distribution characteristics.It has the basis and characteristics of the core development of blue-green integration construction.Based on this,this study selected the typical river and lake water systems in Nanhui New City and Fengxian New City for investigation,built an index evaluation system suitable for evaluating urban bluegreen space by analyzing the current situation of blue-green integration in the study area,and put forward reasonable suggestions through the analysis of the evaluation results,providing basis for subsequent blue-green space construction,as well as for ecosystem restoration and urban ecological construction,It provides reference for the construction of blue-green integration in the Yangtze River Delta.(1)Based on the construction of blue-green space of typical river and lake systems in Shanghai,six first-level indicators of water quality,biological diversity,landscape diversity,hydrological morphological characteristics,riverbank stability and ecological security are selected from three aspects of water body,biology and landscape ecology,and 12 second-level indexes are set as the criterion layer to build the indicator evaluation system,calculate the weight and determine the evaluation criteria,Analytical hierarchy process was used to evaluate the blue-green fusion of the sample points.The evaluation results show that the average score of the blue-green spatial integration degree of the river system in the selected survey area is 70.575,and that of the lake area is 65.774.Among the 8 selected river sample points and 8 lake sample points,the number of sample points reaching the high fusion level is 4 and 6respectively.The river system is healthier than the blue-green space around the lake area,the ecosystem is more complete,and the ecological service function is more perfect.The degree of blue-green spatial integration of river system is mainly affected by hydrological morphological characteristics and riparian conditions,and the lake area is mainly affected by water quality and hydrological morphological characteristics.The difference of the blue-green spatial integration degree of the selected river and lake systems is mainly reflected in the two indicators of revetment ecology and green accessibility.According to the evaluation results,the construction of blue-green space is seriously affected by human interference,and the river bank is highly hardened.In the subsequent urban planning,appropriate development should be carried out on the basis of protecting the original natural form,while increasing supervision,improving relevant laws and regulations,and promoting the construction of blue-green integration.(2)Starting from the ecological service function and combining with the structural characteristics of the blue-green space,this paper classifies the blue-green space ecological service function into three types: public activity type,life service type and ecological conservation type for index screening,uses AHP and EWM to calculate the comprehensive weight and optimize the blue-green space index evaluation system,and evaluates the blue-green space construction quality of the selected artificial lakes and rivers.The results show that there are significant difference in time and space in the comprehensive evaluation results of blue-green space in the study area.From the perspective of space,the quality of ecological service in the blue-green space of the artificial lake area in winter and spring is better than that of the river area,and that in summer and autumn is better than that of the artificial lake area.In terms of time,the score of river area in summer and autumn is slightly lower than that in winter and spring,and the score of artificial lake area is the same..The sample points with the best ecological service quality of the blue-green space in the artificial lake area throughout the year are L6,and the sample points with the best ecological service quality of the blue-green space in the river area throughout the year are R4.In summary,the construction quality of blue-green space of Shanghai river and lake system in summer and autumn is better than that in winter and spring,the ecological service function is gradually getting better,the ecosystem structure is more complete,and the function is more perfect.