摘要
以浙江省龙游县灵山港滩地沉积物为研究对象,在现场监测和室内测定的基础上,运用分形方法,分析了山丘区中小河流滩地沉积物空间分布格局及其影响因素。结果表明:滩地沉积物在空间分布上具有明显的分段、分区、分层特征。土壤分形维数从上游至下游呈增大趋势;在河道横断面上,离水0～16 m为土壤分形维数的高变幅区,离水16～49 m为低变幅区,离水49 m到滩地边界为平稳区;垂向上,0—20 cm层土壤分形维数小于20—40 cm层。砾石分形维数从上游至下游逐渐增大;在河道横断面上,砾石主要分布在离水边缘4～33.5 m范围内,在该范围内,砾石分形维数随离水距离增大而增大。沉积物空间分布差异性主要受水流、植被、采砂、滩地地形和周期性洪水等因素的影响。对于采砂严重的滩地,修复中需要考虑沉积物分布的分段、分区、分层特点,配置组成适宜的基质,保证滩地的稳定和功能的有效发挥。
The Lingshan River, in Longyou County, Zhejiang Province, was taken as a typical example of small and medium rivers in hilly area, and the spatial distribution of deposition and its impact factors were studied based on the fractal theory. The deposition has obvious segmented, zoning and layered features. From upstream to downstream, the fractal dimension of the soil increases. In cross section, it is a high-amplitude region of soil fractal dimension in the distance of 0～16 m from the water, and a low-amplitude region in the distance of 10～49 m from the water, and a stable region in the distance of 49 m from water to the boundary of the floodplain. From vertical view, the fractal dimension of soil in 0—20 cm layer is smaller than that in 20—40 cm layer. From upstream to downstream, the fractal dimension of the gravel increases. In cross section, the gravel mainly distributes in the distance of 4～33.5 m from the water, farther the distance from the water is, larger the stone fractal dimension is. The spatial differentiation of deposition is mainly influenced by flow, vegetation, sediment removal, floodplain topography and periodic flooding and so on. In the floodplain with serious sediment removal, with respect to restoration, the segmented, zoning and layered features should be taken into consideration and suitable matrix should be arranged in order to ensure stability and exertion of function of the floodplains.
引文
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