Geomorphological characteristics of debris flow gullies on the edge of the Qinghai-Tibet Plateau

Xinyue LIANG; Mengzhen XU; Liqun LYU; Yifei CUI; Fengbao ZHANG

doi:10.11821/dlxb202007004

Journals >Acta Geographica Sinica >Volume 75 >Issue 7 >Page 1373 > Article

Acta Geographica Sinica
Vol. 75, Issue 7, 1373 (2020)

Geomorphological characteristics of debris flow gullies on the edge of the Qinghai-Tibet Plateau

Xinyue LIANG^1,2,5,*, Mengzhen XU², Liqun LYU^2,3, Yifei CUI², and Fengbao ZHANG^1,4

Author Affiliations

¹State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation , CAS and Ministry of Water Resources, Yangling 712100, Shaanxi, China

²State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing 100084, China

³Beijing Engineering Research Center of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China

⁴Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, Shaanxi, China

⁵University of Chinese Academy of Sciences, Beijing 100049, China

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DOI: 10.11821/dlxb202007004 Cite this Article

Xinyue LIANG, Mengzhen XU, Liqun LYU, Yifei CUI, Fengbao ZHANG. Geomorphological characteristics of debris flow gullies on the edge of the Qinghai-Tibet Plateau[J]. Acta Geographica Sinica, 2020, 75(7): 1373 Copy Citation Text

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Fig. 1. Spatial distribution of debris flow disasters and earthquakes on the Qinghai-Tibet Plateau

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Fig. 2. Spatial distribution of debris flow gullies in the catchments and along the longitudinal profiles of the main streams

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Fig. 3. Clusters of debris flow gullies in the two-dimensional space obtained by NMDS

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Fig. 4. Variation in morphologies among the three types of debris flow gullies

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Fig. 5. Characteristics of the three types of debris flow fans

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Fig. 6. Hack profiles and SL/K indices of nine rivers

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Fig. 7. Hydrodynamic characteristics of the three types of debris flow gullies (a. Relation between TWI and slope; b. Relation between SPI and slope)

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地貌参数	公式	公式释意
面积(A)	通过ArcGIS水文分析模块提取	面积是泥石流物源条件的反映,面积较大的沟谷有更多滑坡、崩塌为泥石流发生提供松散物质。
坡度(S)	$S = ta n^{- 1} (\frac{H_{h}}{L_{h}})$	H_h为岩体垂直高度;L_h为水平长度。坡度反映松散物补给方式和汇流速度,坡度越陡,松散物越容易启动。
主沟长度(L)	通过ArcGIS水文分析模块提取	主沟越长,越利于增加水量,接纳和搬运的松散碎屑物越多。
比降(G)	$G = \frac{∆ H}{∆ L}$	$∆ H$ 为海拔变化; $∆ L$ 为长度变化。比降反映沟道演化状况,表征泥石流沟水动力条件和物质输送能力,在一定范围内,比降越大越易爆发泥石流。
高差(RA)	$RA = h_{\max} - h_{\min}$	h_max和h_min分别是流域内的最高和最低海拔;RA表示切口深度和地表剥蚀程度,反映流域构造活动强度和能量条件。高差越大,越易发生泥石流。
沟谷形状指数(R_f)	$R_{f} = \frac{A}{L^{2}}$	R_f反映沟谷的汇水和水动力条件。R_f大,沟道中洪峰流量越大,越有利松散物质的起动。
面积—高程积分值(HI)	$HI = \frac{h_{mean} - h_{\min}}{h_{\max} - h_{\min}}$	h_mean表示是流域内的平均海拔。HI反映流域受侵蚀程度,HI越大,表明流域演化阶段越年轻,可蚀性越大。
纵剖面形态指数(N)	$h = H {(\frac{l}{L})}^{N}$	h及l：纵剖面上某点与河口的高差及距离;H及L：河源与河口之间的高差及水平距离;N反映泥石流发育地貌条件,可将泥石流分为幼年期、壮年期和老年期。
沟壑密度(GD)	$GD = L_{总} / A$	L_总为沟谷河流的总长;GD反映流域发育的完善程度。沟壑密度越大的地区,不稳定面越多,边坡稳定性越弱,发生泥石流的可能性也越大
植被覆盖度(FVC)	$FVC = \frac{(NDVI - NDV I_{soil})}{(NDV I_{veg} - NDV I_{soil})}$	NDVI_soil是裸土或者无植被覆盖区域的NDVI;NDVI_veg是完全被植被覆盖的NDVI。通常植被覆盖度越高,坡面越稳定。

Table 1. Main factors affecting the occurrence of debris flows

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