Natural Hazards and Earth System Science www.nat-hazards-earth-syst-sci.net 1561-8633 1684-9981 10 8 2010 10.5194/nhess-10-1689-2010 http://www.nat-hazards-earth-syst-sci.net/10/1689/2010/ http://www.nat-hazards-earth-syst-sci.net/10/1689/2010/nhess-10-1689-2010.html http://www.nat-hazards-earth-syst-sci.net/10/1689/2010/nhess-10-1689-2010.pdf 1689 1695 2010-08-18 On the application of kinematic models to simulate the diffusive processes of debris flows M. Arattano massimo.arattano@irpi.to.cnr.it L. Franzi Research National Council, Torino, Italy Public works, soil defence department, Regione Piemonte, Torino, Italy Debris flows generally propagate along steep mountain torrents with dynamics primarily governed by gravitational and frictional forces. Thus, debris flows modelling can be successfully performed through the application of kinematic models, which consider only the effects of slope and friction and neglect the remaining terms of the momentum equation. However, the diffusion processes that can be observed in the field, such as the spreading of the debris flow wave as it flows downstream, can not be theoretically predicted by kinematic models, since diffusion is a second-order process neglected in the kinematic approximation. In this paper, this issue is discussed and an application for both a generalized diffusion wave model and a kinematic model is proposed of a debris flow which occurred in an Italian instrumented torrent to identify, in a real case scenario, the effective value of the neglected terms in the kinematic approximation. Abbott, M. B. and Cunge, J. A.: Engineering Application of Computational Hydraulics, Pitman Books Limited, 1982. Arattano, M., Franzi, L., and Marchi, L.: Influence of rheology on debris-flow simulation, Nat. Hazards Earth Syst. Sci., 6, 519–528, doi:10.5194/nhess-6-519-2006, 2006. Arattano, M., Deganutti, A. M., and Marchi, L.: Debris flow monitoring activities in an instrumented watershed on the Italian alps, in: Proceedings of the First International ASCE Conference on Debris-Flow Hazard Mitigation: Mechanics, Prediction and Assessment, San Francisco, Ca, 506–515, 7–9~August 1997 Arattano, M. and Marchi, L.: Systems and sensors for debris-flow monitoring and warning, Sensors, 8, 2436–2452, 2008. Arattano, M. and Savage, W. Z.: Modelling debris flows as kinematic waves, Bull. Int. Assoc. Eng. Geol., 49, 95–105, 1994. Chow, V. T.: Open channel hydraulics, McGraw-Hill, Tokyo, 1959. Genevois, R., Tecca, P. R., Berti, M., and Simoni, A.: Debris flows in the dolomites: experimental data from a monitoring system, in: Proceedings of the 2nd International conference on debris flows hazard mitigation: mechanics, prediction and assessment, Taipei, Taiwan, 283–29, 16–18 August 2000. Hürlimann, M., Rickenmann, D., and Graf, C.: Field and monitoring data of debris-flow events in the Swiss Alps, Can. Geotech. J., 40(1), 161–175, 2003. Iverson, R. M.: The Physics of Debris Flows, Rev. Geophys., 35(3), 245–296, 1997. Johnson, A. M.: Physical processes in Geology, Freeman, Cooper and Co, 1970. Lanzoni, S. and Tubino, M.: Rheometric experiments on mature debris flows, in: Proceeding of the 25th I.A.H.R. congress, Tokyo, Japan, 47–54, 30~August–3~September 1993. Lighthill, M. J. and Whitham, G. B.: On kinematic waves, in: Flood movement in long rivers, P. R. Soc. Lond A, Piccadilly, London, 281–316, 10~May 1955. Pierson, T. C.: Flow behaviour of channelized debris flows, Mount S Helens, Washington, in: Hillslope processes, edited by: Abraham, A. D., Allen & Unwin, Boston, 269–296, 1986. Pierson, T. C., Janda, R. J., Thouret, J. C., and Borrero, C. A.: Perturbation and Melting of Snow and Ice by the 13 November 1985 Eruption of Nevado del Ruiz, Colombia, and Consequent Mobilization, Flow and Deposition of Lahars, J. Vulcanol. Geoth. Res., 41, 17–66, 1990. Ponce, V. M.: Kinematic Wave Modelling Where Do We Go From Here?, in: Proceedings of the International Symposium on Hydrology of mountainous areas, Shimla, India, 485–495, 28–30~May 1992. Ponce, V. M.: The kinematic wave controversy, J. Hydraul. Eng.-ASCE, 117(4), 511–525, 1991. Pudasaini, S. P., Wang, Y., and Hutter, K.: Modelling debris flows down general channels, Nat. Hazards Earth Syst. Sci., 5, 799–819, doi:10.5194/nhess-5-799-2005, 2005. Takahashi, T.: Debris flows, Balkema, Rotterdam, 1991. Todini, E.: A mass conservative and water storage consistent variable parameter Muskingum-Cunge approach, Hydrol. Earth Syst. Sci., 11, 1645–1659, doi:10.5194/hess-11-1645-2007, 2007.