Experimental investigations of the evolution of step-pools in rills with heterogeneous soils in Yuanmou Dry-Hot Valley, SW China

Deng, Qi; Liu, Hui; Cheng, Wei; Yang, Haiqing; Liu, Gangcai; Luo, Jun; Qin, Fanglu; Yang, Dan; Zhang, Bin

doi:10.1016/j.catena.2020.104690

Cited by 9 publications

(11 citation statements)

References 58 publications

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“…From Equation it follows that the horizontal length l increases with the power 0.74 of z (i.e. a pool becomes longer with increases in the fall height z ), which is in agreement with the result obtained by Deng et al (2020) using field measurements of step–pool units in rills. Moreover, from Equation the following equation is obtained:

R_{cl} = \frac{l s}{2 s^{2}} = 2.21 {(\frac{s}{z})}^{- 0.74}

where the ls /2 s 2 ratio is a dimensionless group R cl , named the longitudinal circularity ratio , representing the ratio of the area of a half ellipse, having two axes equal to l and 2 s , and that of a half circle, having a radius equal to s .…”

Section: Discussionsupporting

confidence: 90%

“…Step–pool units were also detected in rills (Deng et al, 2020; Di Stefano, Nicosia, Palmeri, et al, 2019; Giménez & Govers, 2001; Giménez et al, 2004, 2019), which are erosive channels characterized by a smaller spatial scale than that of streams. If the formation processes of step–pool units in rills were similar to those occurring in streams, then the applicability of Equation for rills would be expected.…”

Section: Introductionmentioning

confidence: 99%

“…In the recent study conducted by Deng et al (2020) in SW China, step–pool units were observed at locations where herb roots, gravel or hard soil clods were distributed through the experimental plots. These materials can improve the soil anti‐scourability of local sites which, in conjunction with the scour of adjoining sites by the erosive flow, advances the development of step–pools.…”

Section: Introductionmentioning

confidence: 99%

“…Research examining step–pool structures in rills is still limited and mainly deals with the relationship between flow pattern and rill topography (Giménez & Govers, 2001; Giménez et al, 2004), the automatic identification of steps and pools (Giménez et al, 2019), the study of flow resistance (Di Stefano, Nicosia, Palmeri, et al, 2019) and the dynamics of the morphological parameters (Deng et al, 2020). These studies are based on both field and laboratory observations.…”

Section: Introductionmentioning

confidence: 99%

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Analysis of rill step–pool morphology and its comparison with stream case

Pampalone

Stefano

Nicosia

et al. 2021

Earth Surf Processes Landf

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In this paper, the morphology of step–pool features is analysed using rill measurements and literature data for streams. Close‐range photogrammetry was used to carry out ground measurements on rills with step–pool units, shaped on a plot having slope equal to 14, 15, 22, 24 and 26%. Data were used to compare the relationships between H/L, in which H is the step height and L is the step length, and the mean gradient of the step–pool sequence, Sm, for streams or the slope of the step–pool unit, S, for rills. The relationship of H/L against Sm is widely used to test the occurrence of the maximum flow resistance condition in streams, which is associated with the range 1 ≤ (H/L)/Sm ≤ 2. Further analyses were carried out to compare both the formation process and the profile of the pool in rills with those related to streams. Moreover, for a single rill channel, an analysis of flow characteristics expressed in terms of Darcy–Weisbach friction factor and Froude number was developed. The results allowed us to state: (i) the relationships of H/L versus Sm and S are quite similar and the steepness ratio for streams, (H/L)/Sm, and for rills, (H/L)/S, generally ranges from 1 to 2; (ii) the formation process and the profile of the pool in rills are not consistent with those occurring in streams; (iii) in the rills, the longitudinal size of the pool is dominant with respect to the maximum scour depth; (iv) the presence of a sequence of step–pool units within a rill segment noticeably increases flow resistance compared to segments with a flat bed; (v) the Froude number of the flow over the sequence of step–pool units in rills is slightly below the range of 0.8–1 corresponding to the maximum flow resistance in step–pool units.

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R_{cl} = \frac{l s}{2 s^{2}} = 2.21 {(\frac{s}{z})}^{- 0.74}

Section: Discussionsupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Analysis of rill step–pool morphology and its comparison with stream case

Pampalone

Stefano

Nicosia

et al. 2021

Earth Surf Processes Landf

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“…Gully density in the Loess Plateau is greatest in Suide, Liulin, Wubao, and Linxian areas (the gully density is greater than 10.0 km/km 2 ) ( Tian et al, 2013 ), while the Yuanmou Basin has the greatest concentration of gullies in the Jinsha River (dry-hot) Valley ( Chai, Fan & Liu, 2001 ; Xu et al, 2018 ). This spatial differentiation is affected by multiple factors, such as rainfall, vegetation coverage, topography, soils, land use, and human activities ( Deng et al, 2020 ; Gurbanov & Ganieva, 2017 ; Karydas & Panagos, 2020 ; Luffman & Nandi, 2020 ). The dominant factors affecting the distribution of gullies may differ among regions.…”

Section: Introductionmentioning

confidence: 99%

Spatial differentiation of gully clusters based on the regional scale: an example from northeastern China

Zhao

Zhang

Qin

et al. 2020

PeerJ

Self Cite

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Gully erosion represents a serious environmental threat around the world, but their spatial distribution law are unclear at the regional scale. To quantitatively characterize the spatial distribution model of gullies and determine the regularity of regional differentiation, this paper used spatial analyst and statistics method to study the spatial distribution of gullies in 34 sample areas of northeastern China based on interpretations of high-resolution remote sensing images. The results showed that the kernel density could quantitatively describe the continuous spatial clustering of gullies. Gullies in northeastern China had the characteristics of a spatially unbalanced distribution at the scale of the sample area. The average kernel density of the 34 sample areas (Moran’s I was 0.43, P¡0.01P < 0.01) also indicated clustering distribution at the regional scale. The horizontal clustering characteristics of gullies exhibited an azonal distribution of being low values in the middle plain and high values on the three mountainous areas. The average kernel density in the southeastern part of the study area was highest (maximum value of 2.38). In the vertical direction, gullies were relatively undeveloped in low- and high-altitude areas, while middle-altitude areas were beneficial to the development of gullies. The effect of height differences on gully development was more significant than altitude. As the height difference increased, gullies tended to be more clustered, which can be expressed by a power function. The results of this study will not only help to understand the regional differentiation characteristics of gullies but will also provide a scientific reference for the study of spatial distribution of gullies in future.

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