Water pattern changes of Tongxiang City based on multi-source remote sensing data
[Objective]Tongxiang City of Zhejiang Province is a typical"canal town in south of the Yangtze".Its water system has been greatly disturbed by human activities.Assessing the changes of the water system in Tongxiang is of vital importance to optimize the water pattern and enhance the sustainable development.[Method]Based on six multi-source remote sensing images and land use survey data from 1975,1998,2005,2012,2016 and 2019,the water system data were obtained by visual interpretation method.The quantitative changes in the number,structure,shape,function,and spatial distribution of rivers and ponds in Tongxiang since 1975,were studied using river network water system indicators,landscape pattern indices,and spatial overlay analysis.[Result](1)The length and area of rivers in Tongxiang increased before 2005,declined sharply during the period of rapid urbanization,and recovered rapidly after 2016.The length and area of Class-I rivers increased in all phases,but the tributaries changed significantly.(2)The river network density,tributary development coefficient,and fractal dimension increased first,then declined,and finally increased rapidly throughout the process.The river water surface rate continued to grow but the growth rate stagnated significantly during the period of rapid urbanization.The ring degree of river network and the actual integration degree fluctuated continuously and reached its peak in 2016.(3)The variation of river network density in suburban and exurbs was much larger than that of urban areas.Before 2005,the changes of water surface rate were larger in urban area than that in exurbs and suburbs.But during the rapid urbanization period,the changes of water surface rate were larger in urban area than that of suburbs and exurbs.The changes of tributary development index was not significant in exurbs.(4)The areas of pond experienced the same process as that of the river.It first increased,then decreased and finally increased rapidly.And the structure of the pond was constantly changing.The proliferation of farming ponds was the main factor in the change of pond area.The shape of the pond became regular during the development,and its distribution gathered,then dispersed,and finally reconnected.Large-scale aggregation of the pond occurred in in the western of exurbs.[Conclusion]The changes in the water system of Tongxiang in different periods have been greatly influenced by urban development policies,mainly including urbanization development,agricultural structure adjustment,ecological governance,and restoration,and showed obvious periodicity.The characteristics of changes in plain water network cities of the same type are similar and different.[Ch,3 fig.8 tab.36 ref.]
multi-source remote sensingwater system patternspatial and temporal evolutionTongxiang City
国家科技期刊平台
NSTL
万方数据
