, Volume 15, Issue 11, pp 2279–2293 | Cite as

Impacts of small woody debris on slurrying, persistence, and propagation in a low-gradient channel of the Dongyuege debris flow in Nu River, Southwest China

  • Yong-Jun Tang
  • Ze-Min XuEmail author
  • Tai-Qiang Yang
  • Zhen-Hua Zhou
  • Kun Wang
  • Zhe Ren
  • Kui Yang
  • Lin Tian
Original Paper


Debris flows occurring in well-vegetated alpine areas usually contain a range of sizes of woody debris. Large woody debris (LWD), which has a retaining effect on further transportation of debris downstream, is mainly distributed in upstream reaches, and the amount of small woody debris (SWD) deriving from LWD increases dramatically midstream and downstream. The Dongyuege (DYG) bouldery debris flow with a sandy-matrix took place in a wildwood area, causing 96 deaths and its clay-sized fraction does not contain typical clay minerals. However, its total travel distance and runout distance in a low-gradient reach (between 2° and 5°) upstream of the depositional fan apex reached 11 km and 3.3 km, respectively. The abundant SWD in the DYG debris flow might have played a crucial role in slurrying, persistence, and the long runout over the low gradient. To understand why this debris flow extended so far, slurrying experiments, pore water escape experiments, and excess pore pressure experiments were performed. Crude debris (CD) collected from the DYG debris flow deposit was used throughout the experiments, the tested materials of which are separated into CD-containing SWD with a maximum grain size (MGS = 2 mm), purified debris (PD) without SWD with a MGS of 2 mm, and SWD < 2 mm in diameter. In the five slurrying experiments with PD-SWD-water mixtures, as the SWD content was elevated from 0.0 to 2.0 wt%, the current velocity of escaping pore water decreased uniformly from 17.2 to 0.9 mm/s. When the SWD content was 1.0 wt% or greater, the mixtures can be considered as one-phase flows of viscous fluids. The six pairs of pore water escape experiments based on the slurries remolded with CD and PD, respectively showed that the time needed for pore water to escape from the CD slurries was much greater than those from their PD counterparts. Also, measured was the dissipation rate of the relative excess pore pressure of CD and PD slurries of various densities and volumes, which showed that most of the rates of the PD-slurries were always greater than CD-slurries. Overall, the results show that SWD has a strong influence on the slurrying of the DYG debris without typical clay minerals found in other debris flows, and SWD helps to sustain the high excess pore pressure in the interior of the debris flow mass which resulted in the extended travel distance over such a low gradient. SWD favors the formation and stability of one-phase water-debris mixtures because of its large specific surface area and low density, which makes it able to absorb fine particles and able to be suspended in slurry flows over long timescales. In well-vegetated mountainous areas, SWD should be taken into account in the assessment of debris-flow hazards.


Debris flow Vegetation Small woody debris Excess pore pressure Liquefaction Long runout Low-gradient channel 



We are grateful to the editors and the anonymous reviewers for comments that considerably improved the paper.

Funding informationThis work was supported by the National Science Foundation of China-Yunnan Joint Fund (U1502232, U1033601) and the Research Fund for the Doctoral Program of Higher Education of China (20135314110005).


  1. Abe K, Konagai K (2016) Numerical simulation for runout process of debris flow using depth-averaged material point method. Soils Found 56(5):869–888. CrossRefGoogle Scholar
  2. Bardou E, Boivin P, Pfeifer HR (2007) Properties of debris flow deposits and source materials compared: implications for debris flow characterization. Sedimentology 54(2):469–480. CrossRefGoogle Scholar
  3. Berg N, Carlson A, Azuma D (1998) Function and dynamics of woody debris in stream reaches in the central. Can J Fish Aquat Sci 55(8):1807–1820. CrossRefGoogle Scholar
  4. Bilby RE (1981) Role of organic debris dams in regulating the export of dissolved and particulate matter from a forested watershed. Ecology 62(5):1234–1243. CrossRefGoogle Scholar
  5. Bocchiola D, Rulli MC, Rosso R (2006) Transport of large woody debris in the presence of obstacles. Geomorphology 76(1–2):166–178. CrossRefGoogle Scholar
  6. Boivin P, Bardou E, Pfeiffer H (2004) Role and behaviour of clay minerals in alpine debris flows. American Geophysical Union, Fall Meeting 2004, abstract id. H43G-03Google Scholar
  7. Braudrick CA, Grant GE (2001) Transport and deposition of large woody debris in streams: a flume experiment. Geomorphology 41(4):263–283. CrossRefGoogle Scholar
  8. Brayshaw D, Hassan MA (2009) Debris flow initiation and sediment recharge in gullies. Geomorphology 109(3–4):122–131. CrossRefGoogle Scholar
  9. Buffington JM, Lisle TE, Woodsmith RD, Hilton S (2002) Controls on the size and occurrence of pools in coarse-grained forest rivers. River Res Appl 18(6):507–531. CrossRefGoogle Scholar
  10. Burrows RM, Magierowski RH, Fellman JB, Barmuta LA (2012) Woody debris input and function in old-growth and clear-felled headwater streams. For Ecol Manag 286(1):73–80. CrossRefGoogle Scholar
  11. Comiti F, Andreoli A, Lenzi MA, Mao L (2006) Spatial density and characteristics of woody debris in five mountain rivers of the dolomites (Italian Alps). Geomorphology 78(1):44–63. CrossRefGoogle Scholar
  12. Coussot P, Meunier M (1996) Recognition, classification and mechanical description of debris flows. Earth Sci Rev 40(3–4):209–227. CrossRefGoogle Scholar
  13. D’Agostino V, Cesca M, Marchi L (2010) Field and laboratory investigations of runout distances of debris flows in the dolomites (Eastern Italian Alps). Geomorphology 115(3–4):294–304. CrossRefGoogle Scholar
  14. De Blasio FV, Breien H, Elverhi A (2011) Modelling a cohesive-frictional debris flow: an experimental, theoretical, and field-based study. Earth Surf Process Landf 36(6):753–766. CrossRefGoogle Scholar
  15. Faustini JM, Jones JA (2003) Influence of large woody debris on channel morphology and dynamics in steep, boulder-rich mountain streams, western cascades, Oregon. Geomorphology 51(1–3):187–205. CrossRefGoogle Scholar
  16. Fetherston KL, Naiman RJ, Bilby RE (1995) Large woody debris, physical process, and riparian forest development in montane river networks of the Pacific Northwest. Geomorphology 13(1–4):133–144. CrossRefGoogle Scholar
  17. Gomi T, Sidle RC, Bryant MD, Woodsmith RD (2001) The characteristics of woody debris and sediment distribution in headwater streams, southeastern Alaska. Can J For Res 31(8):1386–1399. CrossRefGoogle Scholar
  18. Haga H, Kumagai T, Otsuki K, Ogawa S (2002) Transport and retention of coarse woody debris in mountain streams: an in situ field experiment of log transport and a field survey of coarse woody debris distribution. Water Resour Res 38(8):1-1–1-16. CrossRefGoogle Scholar
  19. Hampton MA (1979) Buoyancy in debris flows. J Sediment Res 49(3):753–758. CrossRefGoogle Scholar
  20. Iroumé A, Mao L, Andreoli A, Ulloa H, Ardiles MP (2015) Large wood mobility processes in low-order Chilean river channels. Geomorphology 228:681–693. CrossRefGoogle Scholar
  21. Iverson RM, Matthew L, Lahusen RG, Matteo B (2010) The perfect debris flow? Aggregated results from 28 large-scale experiments. J Geophys Res Earth Surf 115(3):438–454. CrossRefGoogle Scholar
  22. Jackson CR, Sturm CA (2002) Woody debris and channel morphology in first- and second-order forested channels in Washington’s coast ranges. Water Resour Res 38(9):16-1–16-14. CrossRefGoogle Scholar
  23. Jakob M (2005) A size classification for debris flows. Eng Geol 79(3–4):151–161. CrossRefGoogle Scholar
  24. Johnson AM, Rodine JR (1984) Debris flow. In: Brunsden D, Prior DB (eds) Slope instability. Wiley, Chichester, pp 257–361Google Scholar
  25. Kaitna R, Palucis MC, Yohannes B, Hill KM, Dietrich WE (2016) Effects of coarse grain size distribution and fine particle content on pore pressure and shear behavior in experimental debris flows. J Geophys Res Earth Surf 121(2):415–441. CrossRefGoogle Scholar
  26. Lancaster ST, Grant GE (2006) Debris dams and the relief of headwater streams. Geomorphology 82(1–2):84–97. CrossRefGoogle Scholar
  27. Lancaster ST, Hayes SK, Grant GE (2003) Effects of wood on debris flow runout in small mountain watersheds. Water Resour Res 39(39):1168. CrossRefGoogle Scholar
  28. Macfarlane WA, Wohl E (2003) Influence of step composition on step geometry and flow resistance in step-pool streams of the Washington cascades. Water Resour Res 39(2):237–245. CrossRefGoogle Scholar
  29. Marcus WA, Marston RA, Jr CRC, Gray RD (2002) Mapping the spatial and temporal distributions of woody debris in streams of the Greater Yellowstone Ecosystem, USA. Geomorphology 44(3):323–335. CrossRefGoogle Scholar
  30. May CL (2002) Spatial and temporal dynamics of sediment and wood in headwater streams in the central Oregon Coast Range. PhD dissertation, Oregon State UniversityGoogle Scholar
  31. May CL, Gresswell RE (2003) Processes and rates of sediment and wood accumulation in headwater streams of the Oregon Coast Range, USA. Earth Surf Process Landf 28(4):409–424. CrossRefGoogle Scholar
  32. Montgomery DR, Abbe TB, Buffington JM, Peterson NP, Schmidt KM, Stock JD (1996) Distribution of bedrock and alluvial channels in forested mountain drainage basins. Nature 381(6583):587–589. CrossRefGoogle Scholar
  33. Morton DM, Alvarez RM, Ruppert KR, Goforth B (2008) Contrasting rainfall generated debris flows from adjacent watersheds at forest falls, southern California, USA. Geomorphology 96(3–4):322–338. CrossRefGoogle Scholar
  34. Mosley MP (1981) The influence of organic debris on channel morphology and bedload transport in a New Zealand forest stream. Earth Surf Process Landf 6(6):571–579. CrossRefGoogle Scholar
  35. Osei NA, Harvey GL, Gurnell AM (2015) The early impact of large wood introduction on the morphology and sediment characteristics of a lowland river. Limnologica 54:33–43. CrossRefGoogle Scholar
  36. Pierson TC (1981) Dominant particle support mechanisms in debris flows at Mt Thomas, New Zealand, and implications for flow mobility. Sedimentology 28(1):49–60. CrossRefGoogle Scholar
  37. Slaymaker O (1988) The distinctive attributes of debris torrents. Hydrol Sci J 33:567–573. CrossRefGoogle Scholar
  38. Steeb N, Rickenmann D, Badoux A, Rickli C, Waldner P (2016) Large wood recruitment processes and transported volumes in Swiss mountain streams during the extreme flood of August 2005. Geomorphology 279:112–127. CrossRefGoogle Scholar
  39. Swanson FJ, Lienkaemper GW, Sedell JR (1976) History, physical effects, and management implications of large organic debris in Western Oregon streams. USDA Forest Service General Technical Report PNW-56. 15 ppGoogle Scholar
  40. Thompson DM (1995) The effects of large organic debris on sediment processes and stream morphology in Vermont. Geomorphology 11(3):235–244. CrossRefGoogle Scholar
  41. Trevora J, Lorid D (2008) Dynamics of large woody debris in small streams disturbed by the 2001 Dogrib fire in the Alberta foothills. For Ecol Manag 256(10):1751–1759. CrossRefGoogle Scholar
  42. Zhou ZH, Ren Z, Wang K, Yang K, Tang YJ, Tian L, Xu ZM (2018) Effect of excess pore pressure on the long runout of debris flows over low gradient channels: a case study of the Dongyuege debris flow in Nu River, China. Geomorphology 308:40–53. CrossRefGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Faculty of Civil Engineering and MechanicsKunming University of Science and TechnologyKunmingChina
  2. 2.Faculty of Land Resource EngineeringKunming University of Science and TechnologyKunmingChina

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