[1]CHAO Zengzu,LIANG Geng,LIU Shisheng,et al.Effects of Rainfall and Land Use on Slope Erosion in Typical Debris Flow Small Watershed[J].Research of Soil and Water Conservation,2023,30(03):19-26.[doi:10.13869/j.cnki.rswc.2023.03.004]
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Research of Soil and Water Conservation[ISSN 1005-3409/CN 61-1272/P] Volume:
30
Number of periods:
2023 03
Page number:
19-26
Column:
Public date:
2023-04-10
- Title:
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Effects of Rainfall and Land Use on Slope Erosion in Typical Debris Flow Small Watershed
- Author(s):
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CHAO Zengzu1, LIANG Geng1, LIU Shisheng2, DANG Guangshan2, ZHOU Yanyan1, YUE Dongxia1
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(1.College of Earth and Environmental Sciences, Lanzhou University, Lanzhou, Gansu 730000, China; 2.Longnan Water and Soil Conservation Ecological Environment Monitoring Sub Station, Longnan, Gansu 746000, China)
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- Keywords:
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slope erosion; rainfall regime; land use; debris flow small watershed
- CLC:
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S157.1
- DOI:
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10.13869/j.cnki.rswc.2023.03.004
- Abstract:
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[Objective]The influence and effect of rainfall and land use on the slope erosion in the debris flow small watershed was revealed to provide scientific basis for ecological control of debris flow. [Methods] The first-level tributary of the Bailong River Basin—the debris flow small watershed of Ganjiagou was taken as the research area, and based on five consecutive years of observation data of the five runoff plots(bare land, sloping farmland, grassland, ridge terraces, economic forest land)that have been built in this watershed, K-means clustering method was used to divided the 46 erosive rainfall events in the basin into three rainfall regimes(type I, type Ⅱ, type Ⅲ)by selecting three rainfall indicators, such as rainfall(P), rainfall duration(D)and maximum 30 min rainfall intensity(I30). The influence and effect of rainfall regimes and land use types on slope runoff and sediment production were quantitatively analyzed based on selecting the average runoff coefficient and average soil loss as the main indicators. [Results]There were differences in the response of runoff and soil loss to rainfall, the average runoff coefficient is the highest for type I rainfall, followed by type Ⅲ and type Ⅱ rainfall. The soil loss decreased in the order: type Ⅱ rainfall>type I rainfall>type Ⅲ rainfall. The maximum 30 min rainfall intensity had the highest positive correlation with the runoff coefficient and soil losses of the five land use types, followed by rainfall and rainfall duration. The average runoff coefficients of the five land use types decreased in the order: bare land>economic forest land>sloping farmland>grassland>ridge terraces, and the soil loss decreased in the order: bare land>sloping farmland>economic forest land>grassland>ridge terraces. Under the interaction of rainfall and land use, there were differences in runoff and soil loss due to different rainfall regimes and land use methods, and it was believed that large-scale planting of olive oil should be avoided in terms of controlling soil erosion and reducing the source of debris flow on slopes. [Conclusion] The maximum 30 min rainfall intensity is the key rainfall index affecting the rainfall erosivity in the basin, the slope erosion can be better controlled by the terraced soil, and the effect of reducing the runoff and sediment of the grassland is remarkable. This research results can provide a scientific basis for the prevention and control of soil erosion and debris flow on slopes.