Gully morphological characteristics in the loess hilly‐gully region based on 3D laser scanning technique

Abstract

Gully morphology characteristics can be used effectively to describe the status of gully development. The Chabagou watershed, located in the hilly‐gully region of the Loess Plateau in China, was selected to investigate gully morphological characteristics using a 3D laser scanning technique (LIDAR). Thirty‐one representative gullies located at different watershed locations and gully orders were chosen to quantitatively describe gully morphology and establish empirical equations for estimating gully volume based on gully length and gully surface area. Images and point cloud data for the 31 gullies were collected, and digital elevation models (DEMs) with 10‐cm resolution were generated. ArcGIS 10.1 was then used to extract fundamental gully morphological parameters covering gully length (L), gully width (WT) and gully depth (D), and some derivative morphological parameters, including gully head curvature (C), gully width–depth ratio (w/d), gully bottom‐to‐top width ratio (WB/WT), gully surface area (Ag) and gully volume (Vg). The results indicated that gullies in the upper watershed and the second order were more developed based on their high values of gully head curvature. The potential for gully development increased from the second order to the fourth order. Within the same gully orders, gullies in the lower watershed were more active with more development potential. A method for differentiating between gully head and gully sidewalls based on the gully head curvature value was proposed with a mean relative error of 8.77%. U‐shaped cross‐sections were widely distributed in the upper watershed and upper positions of a gully, while V‐shaped cross‐sections were widely distributed in the lower watershed and lower positions of a gully. V–L and V–Ag empirical equations with acceptable accuracy were established and can be used to estimate gully erosion in the Loess hilly‐gully region. Copyright © 2017 John Wiley & Sons, Ltd.

Assessment of crusting effects on interrill erosion by laser scanning

“…Other recently developed imaging techniques, such as Structure from Motion (SfM), have also been applied to detect small soil surface variations (Vinci et al, 2017;Krenz & Kuhn, 2018) or to point out the spatial distribution of erosion and deposition hotspots at plot scale (Remke et al, 2016;Krenz & Kuhn, 2018). Terrestrial or airborne laser scanning have also been widely used to investigate slope-scale rill erosion or catchment-scale gully morphology (Vinci et al, 2015;Wu et al, 2018). However, all these studies and methods lack the millimeter-scale resolution required for the assessment of crust formation and its effects on flow hydraulics and soil resistance to erosion (Eltner et al, 2015).…”

Accuracy Assessment of Semi-Automatic Measuring Techniques Applied to Displacement Control in Self-Balanced Pile Capacity Testing Appliance

“…Typical applications of airborne laser scanning in the geological investigation (extraction of surface land collapses, landslides, and fault structures) have been compiled in Reference [ 36 ]. Using laser scanning for morphological characteristics of gullies and for monitoring gully changes was given in References [ 37 , 38 ]. Typical applications of laser scanning in civil engineering include, among others, detailed inventory of concrete industrial heritage [ 39 ], precise 3D building modeling [ 40 ], extraction and classification of power lines [ 41 ], and monitoring tunnel deformation [ 42 ].…”

Identification of Active Gully Erosion Sites in the Loess Plateau of China Using MF-DFA

“…Taking the river basin outlet as the starting point, the section data of gully shoulder lines were sampled at 5-m intervals in the direction of the gully shoulder lines ( Figure 1). The number of sample points on the profiles of gully shoulder lines in the six study sites was Shenmu (11,398), Suide (15,825), Yanchuan (16,132), Ganquan (10,767), Yijun (10,643), and Chunhua (7162).…”

“…However, if the analysis scale is too small, the sample is not large enough to calculate the local RMS, leading to errors during the calculation. Thus, an analysis scale range of [7,9,11,13,15,17] was used in this study, which provides a stable local RMS calculation for the shoulder line profile (Figure 11a-f).…”

“…Previous research on loess gully erosion has made important advances with respect to erosion types [14], gully erosion asymmetry [15], the extraction and regional differences of gully erosion [16], gully erosion processes [17], the morphology and transformation of active erosion periods [2], gully erosion evaluation and zoning [18], and the dynamic monitoring of gully erosion development [19]. However, further research is required to determine the horizontal/lateral stability of gully erosion in small watersheds in different types of loess landform and to develop an effective evaluation method for gully erosion activity at different scales that can successfully combine global measurements with local analysis.…”