Assessing sediment connectivity and its spatial response on land use using two flow direction algorithms in the catchment on the Chinese Loess Plateau  

作　　者：YAN Xi-qin JIAO Ju-ying TANG Bing-zhe LIANG Yue WANG Zhi-jie 

机构地区：[1]State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau,Institute of Soil and Water Conservation,Chinese Academy of Sciences and Ministry of Water Resources,Yangling 712100,China [2]Institute of Soil and Water Conservation,Northwest A&F University,Yangling 712100,China [3]University of Chinese Academy of Sciences,Beijing 100049,China [4]College of Life Sciences,Guizhou University,Guiyang 550025,China

出　　处：《Journal of Mountain Science》2022年第4期1119-1138,共20页山地科学学报（英文）

基　　金：supported by the National Natural Science Foundation of China(42077078,U2243213)。

摘　　要：Severe soil and water loss have led to widespread land degradation on the Loess Plateau in China.Exploring the relationship between land use and sediment connectivity can be beneficial to control soil erosion.In this study,three catchments in the Yanhe River Basin on the Loess Plateau were selected to analyse the relationship between land use and sediment connectivity using grey correlation method.Index of connectivity(IC)was employed to quantify sediment connectivity,including two flow direction algorithms(D8 and D-infinity)and two final targets of sediment transport(outlet and main channel of catchment).Then,11 landscape metrics were used to evaluate the land use spatial patterns of catchments.By comparing the IC value ranges,histograms and classes,and their relationship with remote sensing images of the two flow direction algorithms,we find that the D8 algorithm is more suitable for this study area.The results showed that the three catchments are characterized by high sediment connectivity in the grassland and forest close to the channel.In addition,the roads and bare land close to the channel also have high or medium sediment connectivity.Grey correlation analysis showed that landscape division index(DIVISION),fractal dimension index(FRACMN),aggregation index(AI),total class area,patch cohesion index(COHESION),and largest patch index(LPI)indices were the main factors that affect sediment connectivity at the class scale.At the landscape scale,the landscape shape index(LSI),Shannon’s diversity index(SHDI),and gully density have an essential effect on sediment connectivity.This condition provides a way to control the sediment connectivity in the watershed by transforming land use type or changing its spatial pattern,but specific adjustment measures have to be further explored.

关 键 词：Sediment connectivity Land use Landscape metrics CATCHMENTS Loess Plateau 

分 类 号：P901[天文地球—自然地理学]