12.5 Conclusions
205
12.5 Conclusions
PSDSS showed a great difference before and after mass failures. As the gravity erosion occurred, the proportion of sand-sized particles was decreased from 71 to 51%,
whereas the proportions of clay and silt were increased remarkably from 1 to 7%
and 28 to 42%, respectively. Besides, the PSDSS had a significant difference among
different gravitational erosion types. The d 50 , H and D were significantly correlated
with gravity erosion. As a result of gravity erosion, d 50 was decreased from 0.084 to
0.051 mm, H was increased from 5.6 to 26.8, and D was increased from 2.60 to 2.78.
The results imply that gravity erosion made the PSDSS more non-uniform and irregular. Suspended sediment tended to enrich in the silt and clay fractions and dilute in the
sand fractions during mass movement, with R ed s of 13.9, 1.4 and 0.7 for clay, silt, and
sand, respectively. The changes of PSDSS after mass failures reflected a combined
complex effect of soil sources, erosion types, selective detachment and deposition
processes. Mass failures led to the drastic increase of sediment concentration and the
enrichment of fine particles, which developed hyperconcentrated flows.
References
Abarca M, Guerra P, Arce G, et al. 2016. Response of suspended sediment particle size distributions
to changes in water chemistry at an Andean mountain stream confluence receiving arsenic rich
acid drainage. Hydrological Processes, 31(2): 296–307.
Abrahamson J. 1975. Collision rates of small particles in a vigorously turbulent fluid. Chemical
Engineering Science, 30(11): 1371–1379.
Acharya G, Cochrane T, Davies T, et al. 2011. Quantifying and modeling post-failure sediment
yields from laboratory-scale soil erosion and shallow landslide experiments with silty loess.
Geomorphology, 129(1–2): 49–58.
Alberts E E, Moldenhauer W C, Foster G R. 1980. Soil aggregates and primary particles transported
in rill and interrill flow. Soil Science Society of America Journal, 44(3): 590–595.
Asadi H, Moussavi A, Ghadiri H, et al. 2011. Flow-driven soil erosion processes and the size
selectivity of sediment. Journal of Hydrology, 406(1–2): 73–81.
Beuselinck L, Govers G, Hairsine P B, et al. 2002. The influence of rainfall on sediment transport
by overland flow over areas of net deposition. Journal of Hydrology, 257(1–4): 145–163.
Chorley R J. 1964. Geography and analogue theory. Annals of the Association of American
Geographers 54(1), 127–137.
Cochrane T A, Acharya G. 2011. Changes in sediment delivery from hillslopes affected by shallow
landslides and soil armouring. Journal of Hydrology, 50(1): 5–18.
Collins A L, Walling D E, Leeks G J L. 1997. Source type ascription for fluvial suspended sediment
based on a quantitative composite fingerprinting technique. Catena, 29(1): 1–27.
Crosta G B, Frattini P, Fusi N. 2007. Fragmentation in the Val Pola rock avalanche, Italian Alps.
Journal of Geophysical Research Earth Surface, 112:F01006.
Davies T R, McSaveney M J. 2009. The role of rock fragmentation in the motion of large landslides.
Engineering Geology, 109(1–2): 67–79.
Gao G L, Ding G D, Wu B, et al. 2014. Fractal scaling of particle size distribution and relationships
with topsoil properties affected by biological soil crusts. Plos One, 9(2): e88559.
Govers G. 1985. Selectivity and transport capacity of thin flows in relation to rill erosion. Catena,
12(1): 35–49.
205
12.5 Conclusions
PSDSS showed a great difference before and after mass failures. As the gravity erosion occurred, the proportion of sand-sized particles was decreased from 71 to 51%,
whereas the proportions of clay and silt were increased remarkably from 1 to 7%
and 28 to 42%, respectively. Besides, the PSDSS had a significant difference among
different gravitational erosion types. The d 50 , H and D were significantly correlated
with gravity erosion. As a result of gravity erosion, d 50 was decreased from 0.084 to
0.051 mm, H was increased from 5.6 to 26.8, and D was increased from 2.60 to 2.78.
The results imply that gravity erosion made the PSDSS more non-uniform and irregular. Suspended sediment tended to enrich in the silt and clay fractions and dilute in the
sand fractions during mass movement, with R ed s of 13.9, 1.4 and 0.7 for clay, silt, and
sand, respectively. The changes of PSDSS after mass failures reflected a combined
complex effect of soil sources, erosion types, selective detachment and deposition
processes. Mass failures led to the drastic increase of sediment concentration and the
enrichment of fine particles, which developed hyperconcentrated flows.
References
Abarca M, Guerra P, Arce G, et al. 2016. Response of suspended sediment particle size distributions
to changes in water chemistry at an Andean mountain stream confluence receiving arsenic rich
acid drainage. Hydrological Processes, 31(2): 296–307.
Abrahamson J. 1975. Collision rates of small particles in a vigorously turbulent fluid. Chemical
Engineering Science, 30(11): 1371–1379.
Acharya G, Cochrane T, Davies T, et al. 2011. Quantifying and modeling post-failure sediment
yields from laboratory-scale soil erosion and shallow landslide experiments with silty loess.
Geomorphology, 129(1–2): 49–58.
Alberts E E, Moldenhauer W C, Foster G R. 1980. Soil aggregates and primary particles transported
in rill and interrill flow. Soil Science Society of America Journal, 44(3): 590–595.
Asadi H, Moussavi A, Ghadiri H, et al. 2011. Flow-driven soil erosion processes and the size
selectivity of sediment. Journal of Hydrology, 406(1–2): 73–81.
Beuselinck L, Govers G, Hairsine P B, et al. 2002. The influence of rainfall on sediment transport
by overland flow over areas of net deposition. Journal of Hydrology, 257(1–4): 145–163.
Chorley R J. 1964. Geography and analogue theory. Annals of the Association of American
Geographers 54(1), 127–137.
Cochrane T A, Acharya G. 2011. Changes in sediment delivery from hillslopes affected by shallow
landslides and soil armouring. Journal of Hydrology, 50(1): 5–18.
Collins A L, Walling D E, Leeks G J L. 1997. Source type ascription for fluvial suspended sediment
based on a quantitative composite fingerprinting technique. Catena, 29(1): 1–27.
Crosta G B, Frattini P, Fusi N. 2007. Fragmentation in the Val Pola rock avalanche, Italian Alps.
Journal of Geophysical Research Earth Surface, 112:F01006.
Davies T R, McSaveney M J. 2009. The role of rock fragmentation in the motion of large landslides.
Engineering Geology, 109(1–2): 67–79.
Gao G L, Ding G D, Wu B, et al. 2014. Fractal scaling of particle size distribution and relationships
with topsoil properties affected by biological soil crusts. Plos One, 9(2): e88559.
Govers G. 1985. Selectivity and transport capacity of thin flows in relation to rill erosion. Catena,
12(1): 35–49.