Virtual Only | Track 2 | Session 1. Water & disaster risks

River basin is the linking corridor between many cities in China, and basin ecological infrastructure supports ecological foundation of urban development. The holistic and systematic concept of the basin protection has been widely accepted in China. In research, qualitative research becomes the method most people use in basin ecological holistic analysis. For example, most researchers and planners directly choose nature reserves, large parks and water areas as ecological infrastructure. It is qualitative and empirical, with lacking of process analysis. The qualitative approach easily obtains coarse-grained ecological patterns, and has good practical effect on large scales. However, the basin contains a variety of ecological factors, such as water, mountain, forest, field and so on, and its ecological service function are different at different scales. At the mesoscale and microscale, qualitative method tends to ignore important small-scale ecological land use. Therefore, an analysis framework for evaluating the ecological importance of land use is needed to holistically analyze basin ecological infrastructure at the mesoscale and microscale. This paper establishes a quantitative analysis framework based on multi-ecological factors process analysis. Quantitative analysis provides intuitive results of data, which can judge the ecological importance of land use in basin more accurately and objectively. Ecological infrastructure is the dominating ecological pattern for regional ecological function. The theory of “patch - corridor - matrix” provides a fundamental theory for this paper. The theory is to study ecological structure of different land use types, which is related to contents of importance of ecological land in this paper. Ecological land supplies ecological products for human, and its ecosystem service value (ESV) is a quantifiable indicator of analyzing ecological importance. The Millennium Ecosystem Assessment report, released by the United Nations in 2005, puts forward the concept of ecosystem service (ES). ES is recognized internationally, and some scholars further quantify ecosystem services value (ESV) by using eco-economic methods. A series of quantitative studies are carried out based on ESV. For example, based on ESV, some Chinese scholars conducted quantitative research on ecological spatial pattern evolution, which verify the feasibility of quantitative research based on ESV. Therefore, based on the quantitative analysis of ESV, this paper builds a quantitative analysis framework of basin ecological infrastructure, and applies this framework to a case study of Taihu county basin. The research data can be easily obtained from government statistics and the geospatial data set of the Chinese Academy of Sciences. Firstly, this paper builds a quantitative analysis framework including the land and water. The value equivalent method is used to respectively evaluate geospatial differences of basin ESV for the land and water. Based on the evaluation, the circuit theory is used to analyze the ecological source and corridor of the land, and SCS model is used to analyze the ecological pattern of the water. The quantitative results of the land and water are superimposed to form differences in importance of basin ecological infrastructure. Finally, using the quantitative analysis framework, Taihu county is taken as a case study to analyze holistic pattern and optimization strategies of basin ecological infrastructure. The results show that the quantitative analysis framework proposed in this paper has a better effect on holistic identification of basin ecological infrastructure, and the quantitative results can be conveniently used for planning. In the case study, according to the framework, this paper classifies three types of basin ecological infrastructure with different importance, and puts forward specific optimization strategies for the three types.

In the context of "healthy ageing" and "healthy China" strategy, the role of outdoor public space in promoting the physical, mental and social interaction of the elderly has been increasingly emphasized. This paper investigates the characteristics of individual attributes, social interaction activities and the perception of the waterfront space environment of the elderly interviewed in cold urban waterfront spaces through questionnaire interviews and behavioural scenario analysis, and discusses the relationship between the social interaction activities of the elderly and the waterfront space environment in cold urban cities. The study finds that there is a strong correlation between the social interaction activities of the elderly and the spatial environment in cold urban waterfront spaces, in which environmental characteristics such as accessibility, facility integrity, environmental aesthetics and site comfort have different degrees of influence on the social interaction of the elderly. This paper proposes suggestions for optimising the design of waterfront spaces in cold cities from the perspective of promoting social interaction

Dongting Lake is an important regulation and storage lake in the Yangtze River basin and a necessary ecological security barrier in China. Yueyang Hualin Port wharf is close to the intersection of Dongting Lake and the Yangtze River, which has undertaken diversified ecological, social and economic functions since ancient times. However, due to industrial invasion and shoreline solidification, there were a series of problems with its ecology. For example, the natural shoreline which had natural rocky-bay shape was destroyed, flooded constantly and the and the decline of the surrounding city, environment and industry . In this paper, the historical images, satellite images, and the data of current terrain, water system, vegetation were obtained by literature review, field survey, GIS analysis and other methods. On this basis, first of all, analyzing the historical evolution characteristics, cultural characteristics of Yueyang Hualin Port shoreline and the cause of ecological fragility. Then, to explore the driving mechanism of natural shoreline morphology and plant community structure in Dongting Lake. What is more, finding the resilience elements of natural shoreline. Finally, four major shoreline spatial resilience strategies are proposed in this paper, which are 1) Reshaping the site topography to restore the natural rocky-bay shoreline and reproduce the ancient natural geographical characteristics of shoreline. 2) Building hidden dike for resisting flood disaster and improving the landscape. 3) Selecting proper plants in the water-level fluctuation zone to create elastic space. 4) Updating the service function of the site and designing the cultural landscape to provide a public space for the surrounding communities. This strategy aims to maintain physical and mental health and prevent disasters for residents. Only by doing these, can the harmonious coexistence of man and nature and sustainable development in the future achieve.

Under the influence of global climate change and urbanization, sea-level rise and frequent extreme weather caused by climate warming are gradually threatening the safety of coastal cities. The empirical area, the Yangtze River Delta, is located in the eastern coastal area of China, facing the compound risk of rainstorm and sea-level rise. However, there are few studies on regional flood risk simulation and adaptive planning to deal with the impact of global change. Moreover, the potential composite flood risk mechanism caused by rainstorm and sea-level rise is still unknown. This study mainly introduces the scenario matrix simulation method according to RCPs-SSPs(CMIP6) into simulating the compound flood risk scenario based on the coupling scenarios of different typical concentration paths and shared socio-economic paths. In response to the simulation results, a set of regional flood complex adaptive system is constructed to provide a framework for the realization of the goal of climate resilience in the Yangtze River Delta. Finally, this empirical study provides creative research ideas and strategic references for the adaptation and mitigation of climate change in the coastal delta region.

In the macro context of global climate change in recent years, the possibility of extreme climate rhythms continues to increase. For cities in the less developed areas of Southeast Asia, on the one hand, due to the low level of economic development, the design and construction of urban flood control facilities are backward, making it difficult to cope with the increasing flooding and inundation during the rainy season each year; on the other hand, rapid urbanization has led to the encroachment of more and more informal settlements into the waterfront areas of the cities, increasing the possibility of flooding and posing a serious threat to the safety of these communities. The ancient city of Mrauk-U, Myanmar, located in Rakhine State in southwestern Myanmar, is one of the least economically developed regions in Myanmar and has been one of the most severely affected by floods in recent years, but historically has rarely suffered from floods due to the city's outstanding flood control and drainage hydraulic system. Taking Mrauk-U as an example, this paper introduces historic urban landscape (HUL) approach and attempts to explore a localized, low-cost and sustainable path for the conservation and management of the hydraulic system as heritage by analyzing the wisdom of construction of the historical flood control hydraulic system in Mrauk-U, and the vulnerability of the hydraulic system in the face of current socio-economic pressures and climate change impacts, taking into account the development framework of the city, so as to enhance the resilience of the city.

The problem of urban waterlogging has consistently affected areas of Henan province in China by 2020, and has generated widespread concerns among the public and professionals. In this research, the urban areas of Zhengzhou and Xinxiang, which suffered the most severe waterlogging disaster in July 2020, were selected as the research area. On this basis, the site remote sensing map data on July 20, 2020 were obtained by GF-3 satellite, which was used to interpret the distribution of rainwater inundated areas after waterlogging disaster. At the same time, eCognition 9.0 and BigeMAP platform were used to obtain high-precision land cover data in the research area, and combined with FRAGSTATS, the landscape pattern index of each region was calculated. Finally, the correlation between urban waterlogging and land landscape pattern index was analyzed by a series of Moran's I index. Several key results were obtained. (1) Among land cover types, construction land and cultivated land have the greatest impact on waterlogging disaster, and their ability to aggravate regional waterlogging disaster is stronger than that of forest land, grassland and other ecological space. (2) In the landscape pattern index, building COHESION, forestland DIVISION, grassland DIVISION and COHESION, square LPI showed a more significant correlation with waterlogging disaster. This study demonstrated that landscape pattern had significant effect on waterlogging and could provide reference for control of waterlogging and planning management of landscape pattern.