GIS‐based susceptibility assessment of the occurrence of gully headcuts and pipe collapses in a semi‐arid environment: Golestan Province, NE Iran

Abstract

When the effect of two soil erosion features, in this study, gully headcuts (GHs) and pipe collapses (PCs), is investigated jointly, a new comprehensive concept related to their controlling factors can be found. The objective of this paper to evaluate susceptibility to these two features in the hilly region of the Golestan Province (NE Iran), which may be helpful in land management and the sustainable development of the region. The maps of the controlling factors of GHs and PCs were constructed and the random forest algorithm was used to prioritize the factors controlling the occurrence of these two soil erosion features. The GHs and PCs susceptibility maps were prepared using the random forest model in the R software and validated applying the receiver operating characteristic curves, fourfold plot, and Cohen's kappa index, whereas the susceptibility map of the two soil erosion features was prepared by overlapping these maps. The results of factor importance analysis have indicated that land use, slope, and silt content are the most important factors in the occurrence of PCs, whereas slope gradient, silt content, and distance to streams are the most important in GHs occurrence. This means that steep and uncultivated slopes in the study area are most susceptible to GHs and PCs. The susceptibility models of GHs and PCs have excellent accuracy, that is, the area under the receiver operating characteristic curve values of GHs and PCs models were 0.960 and 0.935, respectively. The susceptibility map of GHs and PCs analysed jointly has shown that 66% of the area is not susceptible to any of these soil erosion features, whereas 15% is susceptible to both of them. The places susceptible to the two types of soil erosion features (GHs and PCs) indicate the areas where there is a high probability of GHs retreat due to the PCs. This study has confirmed that it is feasible to forecast the spatial behaviour of GHs and PCs occurrence and development. This is particularly preferred when the developed methods are applied for the susceptibility evaluation under various mitigation scenarios.

Assessing and mapping multi-hazard risk susceptibility using a machine learning technique

“…There are several advantages that make the RF model suitable for the approach in the present study. First, it is a simple, fast algorithm that makes no statistical assumptions and is characterized by a high prediction performance 54,55 . It produces an internally unbiased evaluation of generalizability with an accurate classifier during the forest building processes 26 and provides better consistency of results and robustness of forecasts 56 .…”

How does land use/cover influence gully head retreat rates? An in‐situ simulation experiment of rainfall and upstream inflow in the gullied loess region, China

“…Rainfall and the drainage area are the two most important impacting factors causing variations in GHR rates at local and global scale (Beer & Johnson, 1963;Rieke-Zapp & Nichols, 2011;Thompson, 1964;Vanmaercke et al, 2016). Furthermore, soil physicochemical properties determine the susceptibility of gully heads to concentrated flow scouring and seepage and subsequent piping and thereby significantly affect GHR rates (Faulkner, 1995;Kariminejad, Hosseinalizadeh, Pourghasemi, Bernatek-Jakiel, & Alinejad, 2019;Oostwoud Wijdenes, Poesen, Vandekerckhove, & Ghesquiere, 2000;Vandekerckhove, Poesen, Oostwoud Wijdenes, & Gyssels, 2001;Vanwalleghem, Poesen, Nachtergaele, & Verstraeten, 2005). Moreover, land use/cover, generally involves various vegetation cover conditions, soil properties, and management policies and may directly affect GHR.…”

Analytical techniques for mapping multi-hazard with geo-environmental modeling approaches and UAV images

“…They are classified according to their movement type and composite materials 7 , 8 . Piping erosion divided into two groups, including closed depressions and sinkholes, is also defined as one hazard that has a complex interaction with gully heads 9 and landslides. Closed depressions initiated when the soil surface steadily lowered above a surface with no break in the vegetation cover 10 ; these can eventually change into sinkholes.…”