山丘区中小河流滩地时空演化与扰动因子分析

Temporal and Spatial Evolution of Floodplain and Its Disturbance Factors of Small and Medium Rivers in Hilly Area

滩地是维护河流健康的重要屏障。以浙江省龙游县灵山港滩地为研究对象,利用不同年份的图件资料获取河道滩地几何参数、位置信息等,应用景观格局理论,计算滩地破碎度指数、扰动度等,分析灵山港滩地景观格局时空演化特征,并应用灰色关联方法分析不同年份不同扰动因子对滩地演化扰动度的贡献度。结果表明:(1)从1982-2013年,灵山港滩地格局变化明显,且在2003-2010年变化更显著,从上游到下游,滩地呈现窄长变化趋势,滩地分布均匀性减弱,破碎程度呈增大趋势;(2)扰动度DI<1.35时,自然扰动因子对河流滩地演化具有较大贡献度;扰动度DI≥1.35时,人为扰动因子对河流滩地演化具有较大贡献度。

To explore the floodplain pattern evolution and disturbance factor of small and medium river floodplain in hilly areas,the author selected floodplains of Lingshan River in Longyou County of Zhejiang Province as the research objects,the geometric features parameters,the position relationship between the floodplains and the basic parameters of the riverbed where the floodplains located were obtained through Google Earth and AutoCAD.Based on the landscape lattice,we can analyze the landscape evolution of floodplains.By introducing the land use degree model to the floodplains disturbance index,and combining with the grey incidence analysis method,the evolution of the floodplains during 1982-2013 periods and the degree of disturbance factor contribution to the disturbance index are analyzed.The results show that: ① from 1982 to 2013,there were obvious changes in the patterns of Lingshan River floodplains.The distribution of floodplains was more and more uneven in space,the degree of fragmentation of floodplains increased gradually,and the floodplains showed a narrow development trend,and the performance was more remarkable from 2003 to 2010.② when the disturbance index is less than 1.35,the natural disturbance factors play a major role in the evolution of floodplains; when the disturbance index is more than or equal to 1.35,the human disturbance factor has a greater contribution to the evolution of the floodplains.