01 colate detritiche_fenomeno_en-2
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1) Debris flows occur when high intensity rainfall generates abundant runoff that entrains large quantities of debris material in channels, forming solid-liquid flows. 2) Debris flows can damage infrastructure and be deadly, as evidenced by photographs of destroyed villages, flooded roads, and debris deposits from past events. 3) Proper modeling of debris flows requires considering the hydrologic, triggering, and hydraulic processes involved - from runoff generation to downstream routing of the solid-liquid mass.
01 colate detritiche_fenomeno_en-2
- 1. Carlo Gregoretti23/5/2017 Mekelle University - Debris Flows Debris Flow: the phenomenon
- 2. Carlo Gregoretti23/5/2017 Mekelle University - Debris Flows Debris flow is a phenomenon occurring when a water stream entrains a large quantity of debris material, so that a solid-liquid current can form and route downstream It is halfway between a landslide and a flood French: Lave torrentielle German: Murgang or Mure Italian: Colata detritica
- 3. Carlo Gregoretti23/5/2017 Mekelle University - Debris Flows Landslide
- 4. Carlo Gregoretti23/5/2017 Mekelle University - Debris Flows Afghanistan, 2007 Debris flow and flood
- 5. Carlo Gregoretti23/5/2017 Mekelle University - Debris Flows Rio Acquabona (Cortina dAmpezzo, km98 SS51, 12 June 1997) Debris flowbasin head area - 1
- 6. Carlo Gregoretti23/5/2017 Mekelle University - Debris Flows Rovina di Cancia (Borca di Cadore, km80 SS51, 23 July 2015) Debris flowbasin head area - 2
- 7. Carlo Gregoretti23/5/2017 Mekelle University - Debris Flows Rovina di Cancia (Borca di Cadore, km80 SS51, 4 August 2015) Debris flowbasin head area - 3
- 8. Carlo Gregoretti23/5/2017 Mekelle University - Debris Flows Debris flowbasin head area - 4 Punta Nera (Cortina dAmpezzo, km97 SS51, 21 July 2016)
- 9. Carlo Gregoretti23/5/2017 Mekelle University - Debris Flows Debris flowbasin head area - 5 Punta Nera (Cortina dAmpezzo, km97 SS51, 5 August 2016)
- 10. Carlo Gregoretti23/5/2017 Mekelle University - Debris Flows Mount Yakedake (Japan, 1994) Debris flowintermediate part of the basin -1
- 11. Carlo Gregoretti23/5/2017 Mekelle University - Debris Flows Illgraben (Svizzera), 28 June 2000 Debris flowintermediate part of the basin - 2
- 12. Carlo Gregoretti23/5/2017 Mekelle University - Debris Flows Monitoring station in the Gadria basin (Prov. of Bolzano), 18 July 2013 Debris flowintermediate part of the basin - 3
- 13. Carlo Gregoretti23/5/2017 Mekelle University - Debris Flows Debris flowintermediate part of the basin - 3 Monitoring station in the Gadria basin (Prov. of Bolzano), 14 July 2014
- 14. Carlo Gregoretti23/5/2017 Mekelle University - Debris Flows https://youtu.be/0ENe7wDKP6I Debris flowintermediate part of the basin - 4 Illgraben 22 July 2016
- 15. Carlo Gregoretti23/5/2017 Mekelle University - Debris Flows Debris flowintermediate part of the basin - 5 Aconguaga (Chile) 26 December 2015
- 16. Carlo Gregoretti23/5/2017 Mekelle University - Debris Flows Debris flowintermediate part of the basin - 6 (Chile) 2017 https://youtu.be/8kdIsQxXUss
- 17. Carlo Gregoretti23/5/2017 Mekelle University - Debris Flows Strengen (Arlberg), 13 July 2010 Debris flow- lower part of the basin - 1
- 18. Carlo Gregoretti23/5/2017 Mekelle University - Debris Flows Debris flow- lower part of the basin - 2 Taibon Agordino (BL) , 11 January 2016
- 19. Carlo Gregoretti23/5/2017 Mekelle University - Debris Flows Debris flow- lower part of the basin - 3 Taibon Agordino (BL) , 11 January 2016
- 20. Carlo Gregoretti23/5/2017 Mekelle University - Debris Flows Ortles, 1 August 2010 (Geosciencie Dept. - Pauda University video) Debris flow glacial till area
- 21. Carlo Gregoretti23/5/2017 Mekelle University - Debris Flows Occurrence of debris flows? Where, how and when they initiate? Runoff descending from channels incised on rocky cliffs entrain debris material laying at their feet, initiating a solid- liquid wave.
- 22. Carlo Gregoretti23/5/2017 Mekelle University - Debris Flows Runoff descending from the channel incised on cliffs impact sediments laying at their feet generating a solid-liquid flow (images of a channel incised on the Mount Cristallo walls).
- 23. Carlo Gregoretti23/5/2017 Mekelle University - Debris Flows Debris flow occurred the 12th of June 1997 at Acquabona Two examples of runoff descending along rocky cliffs filmed at Acquabona (left) and Dimai (right) in the area of Cortina dAmpezzo that initiated debris flows. Debris flow occurred the 18th of August 2011 at Dimai Runoff descending along rocky cliffs - 1
- 24. Carlo Gregoretti23/5/2017 Mekelle University - Debris Flows On the fan at the base of channels incised on the rocky cliffs, runoff action dig channel. On the bottom of these channel, debris deposits due to previous erosive events (rock falls, bank failures, sediment transport) are entrained by runoff corresponding to high intensity rainfalls 9 mm in 15 minutes (7/11/2015) No debris flow occurrence 18 mm in 10 minutes (8/18/2011) Debris flow occurrence Fiames (Cortina dAmpezzo) at the base of Dimai peak Runoff at the base of rocky cliffs - 1
- 25. Carlo Gregoretti23/5/2017 Mekelle University - Debris Flows Debris flow initiation Entrainment en masse of sediments of the deposits laying on the channel bottom into a water stream
- 26. Carlo Gregoretti23/5/2017 Mekelle University - Debris Flows Schematic 2D view of a debris flow event occurrence and development Deposition Debris flows commonly occur in channels draining small steep rock basins located in the upper part of the slopes where high intensity, short duration rainfalls, rapidly generate high runoff discharges , that are able to entrain large debris material laying at the bottom of channel, forming a solid-liquid wave RUNOFF Firehose effect debris flow triggering Formation of an immature debris flow Debris flow increases its velocity and erodes sediment s laying on the bed Formation of a mature debris flow with sediment sorting along the profile Debris flow slows and sediment deposition starts Rock cliffs Scree sediment
- 27. Carlo Gregoretti23/5/2017 Mekelle University - Debris Flows Schematic 3D view of a debris flow event occurrence and development Initiation area Transport area deposition area Debris material availability Very high slopes Abundant runoff
- 28. Carlo Gregoretti23/5/2017 Mekelle University - Debris Flows In brief, a debris flow results from three different physical processes 1. Abundant runoff production after high intensity precipitation 2. Entrainment of debris material laying on the bottom of channels with formation of a solid-liquid wave 3. Downstream routing of the solid-liquid wave We need three different models for debris flow simulations: 1. Hydrologic model (Rainfall-Runoff) for rocky headwater basins 2. Triggering model for determining the solid-liquid hydrograph 3. Hydraulic model for downstream routing Physical processes associated to debris flow
- 29. Carlo Gregoretti23/5/2017 Mekelle University - Debris Flows The effect of a debris flow - 1 Val Pola
- 30. Carlo Gregoretti23/5/2017 Mekelle University - Debris Flows Chieppena torrent (Trentino) November 1966 Venzo e Largaiolli (1968) The effect of a debris flow - 2
- 31. Carlo Gregoretti23/5/2017 Mekelle University - Debris Flows The village of Chiapuzza (San Vito di Cadore, BL) after the debris flow of the 4th of November 1966 The effect of a debris flow - 3
- 32. Carlo Gregoretti23/5/2017 Mekelle University - Debris Flows The effect of a debris flow - 4 Debris flow deposits after the event of 7 August 1996 in Borca di Cadore (Cancia debris flow)
- 33. Carlo Gregoretti23/5/2017 Mekelle University - Debris Flows The effect of a debris flow - 5 Val Pola Nusdorf Debant, Drava Valley, Lienz, Austria - After the debris flow occurred on August 1997 (Fuchs et al., 2007)
- 34. Carlo Gregoretti23/5/2017 Mekelle University - Debris Flows The effect of a debris flow - 6 Val Pola Results from the spilling of mud water from the retaining basin upstream Borca di Cadore (BL) the 18th of July 2009 Retaining wall
- 35. Carlo Gregoretti23/5/2017 Mekelle University - Debris Flows The effect of a debris flow - 7 Val Pola Hamlet of Campolongo di Baselga di Pin竪 (TN) after the debris flow occurred the 15th of August 2010
- 36. Carlo Gregoretti23/5/2017 Mekelle University - Debris Flows The effect of a debris flow - 8 Val Pola The National Road SS. 51 (km 97.500) between Cortina dAmpezzo and San Vito di Cadore (BL) flooded by the debris flow occurred the 8th of August 2015.
- 37. Carlo Gregoretti23/5/2017 Mekelle University - Debris Flows The effect of a debris flow - 7 Val PolaBayi watershed (Longxi river), Wenchuan , China; after the big earthquake of 2008 intese rainfall triggered several debris flows the 13-14th of August 2010
- 38. Carlo Gregoretti23/5/2017 Mekelle University - Debris Flows The effect of a debris flow - 8 Val Pola Bayi watershed (Longxi river), Wenchuan , China; after the big earthquake of 2008 intese rainfall triggered severa debris flows the 13-14th of August 2010
- 39. Carlo Gregoretti23/5/2017 Mekelle University - Debris Flows Reference Fuchs, S., Heiss, K., Huebl J., 2007. Towards an empirical vulnerability function for use in debris flow risk assessment. Nat. Hazards Earth Syst. Sci. 7, 495-506.
- 40. Carlo Gregoretti23/5/2017 Mekelle University - Debris Flows The effect of a debris flow - 9 Val Pola Bayi watershed (Longxi river), Wenchuan , China; after the big earthquake of 2008 intese rainfall triggered several debris flows the 13-14th of August 2010