Quantitative assessment of the influence of terrace and check dam construction on watershed topography

作者：Guowei PANG,Qinke YANG,Chunmei WANG,Rui LI,Lu ZHANG

摘要：Terrace and check dam construction has substantially changed land surface morphology,which in turn affects modern surface processes.Digital elevation models(DEMs)provide an effective way to quantitatively analyze surface morphology and processes.However,existing DEMs lack sufficient ability to express artificial terrain.Based on 1:10000 topographic maps of the Zhifanggou watershed,a series of artificial terrain DEMs for the study site were constructed by both field investigation and remote sensing images from 1938 to 2010.Digital terrain analysis was used to quantitatively assess the influence of terrace and check dam construction on the watershed terrain.The results showed that the artificial terrain DEM could capture the spatial distribution patterns of terraces and dam lands and improved the ability of DEM to express terrain.The construction of terraces and check dams clearly changed the surface elevation.The average elevation change of each terrace mainly ranged between–1.5 and 1.5 m,while the annual average deposition height of the dam lands was 9.16 cm.The average slope,slope length,and slope length and steepness factor of the watershed decreased with the effect of the artificial terrain on the surface,and their averages decreased by 0.65°,6.75 m,and 0.83,respectively,from 1938 to 2010.Although the construction of terraces reduced their surface slope to nearly 0°,the slope of terrace embankments rapidly increased,to more than 45°,which may lead to gravitational erosion and potential terrace damage.Terracing reduced the slope length in both the terrace distribution area and downslope of the terraces.Check dam deposition reduced the slope and slope length of the channel.This study contributes to a better understanding of the topographic change rules after terrace and check dam construction,and aids in elucidating the mechanisms of soil erosion process influenced by artificial topography.

发文机构：Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity Key Laboratory of Ecological Hydrology and Disaster Prevention in Arid Regions Institute of Soil and Water Conservation Key Laboratory of Degraded and Unused Land Consolidation Engineering

关键词：checkdamdigitalelevationmodelLoessPlateauTERRACETOPOGRAPHY

分类号： TN9[电子电信—信息与通信工程]