Landscape Adaptability Evaluation And Proactive Planning Strategies For Coping With Floods And Droughts In River-island

The rapid change of climate makes it normal for flood and drought disasters to occur alternately in the middle and lower reaches of the Yangtze River.Therefore,the Great protection strategy of the Yangtze River emphasizes climate adaptability in urban and rural spatial planning to improve disaster prevention ability.The islands in the river are subjected to more intense hydrological disturbance,and the early planning and development and hard protection have been difficult to cope with the changes,resulting in heavy losses due to disasters and disorderly and slow development of most of them.The current research and practice of copying urban planning and implementing static protection are no longer applicable,and it is urgent to optimize the landscape pattern,reshape the protection system,and improve the disaster adaptability of river-island.This paper selects the middle and lower reaches of the Yangtze River with frequent flood-drought interchanges as the regional background.Firstly,based on the relevant research basis,it proves that the guiding idea of flood-drought planning is to actively adapt to disasters.Based on the in-depth analysis of the connotation of adaptability and the mechanism of flood and drought disaster in river-island,the applicability of the adaptive cycle theory is demonstrated,and the basic intrinsic relationship of dynamic adaptation to flood and drought is clarified.Secondly,the three-dimensional attributes of potentialconnection-resilience and the weighted comprehensive fitness were used as the framework to evaluate the flood and drought adaptability of river-island,and the index system and evaluation method were constructed.Then,Tianxing Island of Wuhan was taken as the research object to obtain data,and its three-dimensional attributes and fitness index were evaluated and analyzed by Arc GIS,ENVI,Fragstats,Geo Da and other software.On the one hand,spatial autocorrelation analysis and obstacle degree analysis were used to study and judge the external representation of comprehensive adaptability.On the other hand,the intrinsic relationship is revealed through the differential combination effect among the three-dimensional attributes.Finally,this paper puts forward the disaster adaptable landscape planning strategy for river-island to cope with flood and drought.The research shows that:(1)The overall adaptability of island landscape to flood and drought presents a pattern of "high in the middle and low in the surrounding areas",with significant aggregation.From2006 to 2016,the adaptability decreases from a high level to a low level,and gradually recovers to a medium level in 2021.In addition to the interference of objective hydrological environment factors,the impact of landscape spatial pattern,especially the degree of connectivity,is the most important;(2)The different combinations of the three-dimensional attribute index reveal the stage characteristics of the system evolution.Based on the adaptive cycle model,it is preliminarily determined that there are four dynamic stages of adaptation to flood and drought in river-island,namely,disturbance-mitigation-restoration-protection;(3)The 3-dimensional index has significant differentiation characteristics in space,and the potential-connectivity index is a summary of the static characteristics of the system.The different combinations of the two in space reflect the main types of landscape in a certain region,and then identify the four functional areas of the disaster-resistant landscape of river-island: fall protection,dynamic buffering,transition drainage and natural penetration.Based on spatial autocorrelation clustering and the main factors affecting adaptability,as well as the evolution process of adaptability and the zonal effect of landscape adaptability to disaster,this paper proposes a landscape active planning strategy for coping with flood and drought disasters in river-island.It is believed that planning optimization can be carried out from four dimensions: regulation potential patches,sound connectivity pattern,comprehensive zoning measures,and graded regulation of resilience.Based on this,the preliminary planning of flood and drought adaptability of Tianxing Island was carried out,in order to provide some ideas for river-island to better adapt to climate change through the research process from evaluation and analysis to spatial location and planning optimization.