Landslides & debris flows formation from gravelly soil surface erosion and particle losses in Jiangjia Ravine

Abstract. Climate change results in more frequent rainstorms and more rain-induced debris flows in mountainous areas. The prediction of likely hazard zones is important for debris flow risk assessment and management. Existing numerical methods for debris flow analysis often require the input of hydrographs at prescribed initiation locations, ignoring the initiation process and leading to large uncertainties in debris flow initiation locations, times and volumes when applied to regional debris flow analysis. The evolution of the flowing mixture in time and space is hardly addressed either. This paper presents a new integrated numerical model, EDDA 2.0, to simulate the whole process of debris-flow initiation, motion, entrainment, deposition and property changes. Two physical initiation mechanisms are modeled: transformation from slope failures and surface erosion. Three numerical tests and field application to a catastrophic debris flow event are conducted to verify the model components and evaluate the model performance. The results indicate that the integrated model is capable of simulating the initiation and subsequent flowing process of rain-induced debris flows, as well as the physical evolution of the flowing mixture. The integrated model provides a powerful tool for analyzing multi-hazard processes, hazard interactions and regional debris-flow risk assessment in the future.

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Comparison of the implementation of three common types of coupled CFD-DEM model for simulating soil surface erosion

International Journal of Multiphase Flow ◽

10.1016/j.ijmultiphaseflow.2017.01.006 ◽

2017 ◽

Vol 91 ◽

pp. 89-100 ◽

Cited By ~ 17

Author(s):

Yuan Guo ◽

Xiong (Bill) Yu

Keyword(s):

Soil Surface ◽

Surface Erosion ◽

Dem Model

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Estimating a mathematical formula of soil erosion under the effect of rainfall simulation by digital close range photogrammetry technique

Journal of Engineering Research ◽

10.36909/jer.8739 ◽

2021 ◽

Author(s):

Hossam El-Din Fawzy ◽

◽

Ali Basha ◽

Marco N. Botross ◽

◽

...

Keyword(s):

Soil Erosion ◽

Sandy Soil ◽

Soil Surface ◽

Rainfall Simulation ◽

Surface Model ◽

Surface Erosion ◽

Hybrid Technique ◽

Mathematical Formula ◽

Close Range Photogrammetry ◽

Close Range

A new design of soil erosion and rainfall simulator is presented at this study as an attempt to deduce a mathematical formula of soil surface erosion phenomenon to describe the behavior of the sandy soil under the rainfall simulation, soil deformation such as the gullies and surface eroding rills are monitored by the Digital Close Range Photogrammetry (DCRP) technique that includes capturing digital images by a smart cellphone camera, and a Terrestrial Laser Scanner (TLS) to digitalize the soil surface as a point cloud data to produce Digital Elevation Models (DEM) with an accuracy reaches 0.10mm with the watershed, color relief, 3D surface model. The results show that the mentioned methods give a typical digital surface feature express especially of using geometrical adjustment that controls the orientation of the digital surface. The SIFT technology of the digital imaging feature detection achieves accurate results despite its small cost, 12% if compared to the TLS method. As a result of the statistical observations, a simple mathematical formula was generated through the DCRP technique that describes the sandy soil behavior under a hybrid technique of rainfall simulation as a relation between the eroding rate and the duration through the different gradient slopes.

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Debris flows: geologic process and hazard; illustrated by a surge sequence at Jiangjia Ravine, Yunnan, China

Professional Paper ◽

10.3133/pp1671 ◽

2004 ◽

Author(s):

Kevin M. Scott ◽

Wang Yuyi

Keyword(s):

Debris Flows ◽

Jiangjia Ravine

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Post-wildfire moss colonisation and soil functional enhancement in forests of the southwestern USA

International Journal of Wildland Fire ◽

10.1071/wf19106 ◽

2020 ◽

Vol 29 (6) ◽

pp. 530

Author(s):

Henry S. Grover ◽

Matthew A. Bowker ◽

Peter Z. Fulé ◽

Kyle D. Doherty ◽

Carolyn H. Sieg ◽

...

Keyword(s):

Pinus Ponderosa ◽

Vegetation Type ◽

Aggregate Stability ◽

Soil Surface ◽

Water Infiltration ◽

Surface Erosion ◽

High Severity ◽

Moss Cover ◽

Southwestern Usa ◽

In Fire

Fire mosses, including Ceratodon purpureus, Funaria hygrometrica and Bryum argenteum, can achieve high cover within months to years after high-severity fire, but do so heterogeneously across space and time. We conducted a survey of moss cover and erosion-related functions after 10 wildfires in Pinus ponderosa and mixed-conifer forests of the southwestern USA. We sampled 65 plots in high-severity patches, stratifying by elevation and insolation over each fire. Using three landscape-scale predictor variables and one temporal predictor, we explained 37% of the variance in fire moss cover using a random forest model. The predictors in order of importance were: equinox insolation (sunlight/day), pre-fire vegetation type, pre-fire soil organic carbon and time since fire. Within each plot we examined differences between bare and moss-covered soil surface microsites and found moss-covered microsites had a mean increase of 55% water infiltration, 106% shear strength, 162% compressive strength and 195% aggregate stability. We tested a suite of nutrients, finding 35% less manganese in the moss-covered soil. This research demonstrated that post-fire colonisation by moss is predictable and that colonisation improves soil surface erosion resistance and hydrological function, with implications for managing severely burned landscapes.

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Slow regolith degradation without creep determined by cosmogenic nuclide measurements in Arena Valley, Antarctica

Quaternary Research ◽

10.1016/j.yqres.2007.12.004 ◽

2008 ◽

Vol 69 (2) ◽

pp. 242-249 ◽

Cited By ~ 15

Author(s):

Jaakko Putkonen ◽

Greg Balco ◽

Daniel Morgan

Keyword(s):

Indirect Evidence ◽

Soil Surface ◽

Ice Cover ◽

Surface Erosion ◽

Dry Valleys ◽

Cosmogenic Nuclide ◽

Exposure Age ◽

Excellent Preservation ◽

Exposure Ages ◽

Landslide Deposit

Estimates of regolith degradation in the McMurdo Dry Valleys of Antarctica are currently based on indirect evidence and ancient ashes at or near the soil surface that suggest excellent preservation of surfaces. On the other hand, the existing cosmogenic-nuclide surface exposure ages from many parts of the Dry Valleys are younger than the age of surface deposits inferred from stratigraphic relations. This suggests some combination of surface erosion or past ice cover, both of which would reduce the apparent exposure age. This paper quantifies the regolith degradation and/or past ice cover by measuring10Be and26Al from a landslide deposit that contains 11.3 Ma volcanic ash. The surface sample yields an apparent exposure age of only 0.4 Ma. However, measurements of the subsurface nuclide concentrations show that the deposit has not been shielded by ice, and that the age of the ash does not conflict with the apparent exposure age when slow degradation of the deposit (2 m Ma−1) is taken into account. Soil creep, which is a common degradational process in a wide variety of environments, is non-existent at this field site, which likely reflects the persistent lack of bio- and cryoturbation.

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