Spatial patterns of exposure to sediment-laden flows on an experimental alluvial fan
DOI:
https://doi.org/10.17735/cyg.v37i1-2.95210Keywords:
alluvial fan, fluvial hazards, exposure, modellingAbstract
Sediment-laden flows with significant amounts of large wood can impact alluvial fans and seriously damage infrastructure and property which makes a profound knowledge of exposure an essential requisite for risk mitigation. To investigate its spatial variability, we executed experiments on a simplified physical model and assessed the observed spatial process and exposure patterns by quantifying synthetic indexes and geostatistically analysing spatial probabilities. We systematically varied the loading conditions, i.e. total flow volume, solid fraction and the tank opening controlling water release, and repeated each experimental configuration eight times. Two alluvial fan layouts were considered, one equipped with a guiding channel and a bridge and one with a guiding channel only. First, we tested the hypothesis, that water released though the fully opened tank outflow valve induces a sediment-laden flow which is associated with higher exposure and lower spatial uncertainty of exposure if compared to flows generated by a half-opened tank outflow valve. Second, we tested whether a higher flow volume is associated with higher exposure on the alluvial fan and with lower spatial uncertainty. It turned out that neither of the aforementioned hypotheses is verified for the whole set of tested flow conditions. The first hypothesis is rejected in the majority of the considered conditions. The second hypothesis is prevailingly corroborated when the exposed areas due to both sediment and water were considered. Instead, when only the areas of sediment deposition are considered, this hypothesis is prevailingly corroborated on the alluvial fan featuring the presence of the bridge. We provided exposure probability maps for all experimental conditions and presented the variability of exposure by standard deviation ellipses. Although solely indicative for the adopted alluvial fan layouts, a variation of the loading parameters led to remarkable changes in the patterns of exposure probability and the parameters of the standard deviation ellipses. Our results urge decision makers to fully acknowledge the potential variability of geomorphic responses on alluvial fans in their risk management practices as to avoid underestimating the impacts for the built environment.
References
Alexander, D. (2000). Confronting Catastrophe. Dunedin Academic Press Ltd, Edinburgh UK, 288 pp.
Bachi, R. (1963). Standard distance measures and related methods for spatial analysis. Papers of the Regional Science Association, 10(1), 83–132. https://doi.org/10.1111/j.1435-5597.1962.tb00872.x
Blair, T.C., McPherson, J.G. (1994). Alluvial Fans and their Natural Distinction from Rivers Based on Morphology, Hydraulic Processes, Sedimentary Processes, and Facies Assemblages. Journal of Sediment Research, 64(3a), 450–489. https://doi.org/10.1306/D4267DDE-2B26-11D7-8648000102C1865D
Blair, T.C., McPherson, J.G. (2009). Processes and Forms of Alluvial Fans. In Parsons, A.J., Abrahams, A.D. (editors). Geomorphology of Desert Environments, (pp. 413–467). Springer Netherlands. https://doi.org/10.1007/978-1-4020-5719-9_14
Bowman, D. (2019). Principles of Alluvial Fan Morphology. Springer, Netherlands, 151 pp. https://doi.org/10.1007/978-94-024-1558-2
Bryant, M., Falk, P., Paola, C. (1995). Experimental study of avulsion frequency and rate of deposition. Geology, 23(4), 365–368. https://doi.org/10.1130/0091-7613(1995)023<0365:ESOAFA>2.3.CO;2
Bubeck, P., Aerts, J.C.J.H., De Moel, H., Kreibich, H. (2016). Preface: Flood-risk analysis and integrated management. Natural Hazards and Earth System Sciences, 16(4), 1005-1010. https://doi.org/10.5194/nhess-16-1005-2016
Bull, W.B. (1977). The alluvial-fan environment. Progress in Physical Geography, 1(2), 222–270. https://doi.org/10.1177/030913337700100202
Clarke, L.E. (2015). Experimental alluvial fans: Advances in understanding of fan dynamics and processes. Geomorphology, 244, 135–145. https://doi.org/10.1016/j.geomorph.2015.04.013
Clarke, L.E., Quine, T.A., Nicholas, A. (2010). An experimental investigation of autogenic behaviour during alluvial fan evolution. Geomorphology, 115(3–4), 278–285. doi: 10.1016/j.geomorph.2009.06.033
Church, M., Dudill, A., Venditti, J.G., Frey, P. (2020). Are results in geomorphology reproducible? Journal of Geophysical Research: Earth Surface, 125(8), e2020JF005553. https://doi.org/10.1029/2020JF005553
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. https://doi.org/10.1016/j.geomorph.2009.06.032
Davies, T.R.H., McSaveney, M.J., Clarkson, P.J. (2003). Anthropic aggradation of the Waiho River, Westland, New Zealand: microscale modelling. Earth Surface Processes Landforms, 28(2), 209–218. https://doi.org/10.1002/esp.449
De Haas, T., Densmore, A.L., Stoffel, M., Suwa, H., Imaizumi, F., Ballesteros-Cánovas, J.A., Wasklewicz, T. (2018). Avulsions and the spatio-temporal evolution of debris-flow fans. Earth-Science Reviews, 177, 53-75. https://doi.org/10.1016/j.earscirev.2017.11.007
Diaz, H., Mazzorana, B., Gems, B., Rojas, I., Santibañez, N., Iribarren, P., Pino, M., Iroumé, A. (2022). What do biphasic flow experiments reveal on the variability of exposure on alluvial fans and which implications for risk assessment result from this? Natural Hazards, 111, 3099–3120. https://doi.org/10.1007/s11069-021-05169-8
Florin, R. (2022). Explorando el alcance de la independencia de escala en la modelación física de la dinámica distributiva en un abanico aluvial. Diploma Thesis, School of Geology, UACh. 92 pp.
Fuchs, S. (2009). Susceptibility versus resilience to mountain hazards in Austria - Paradigms of vulnerability revisited. Natural Hazards and Earth System Sciences, 9(2), 337–352. https://doi.org/10.5194/nhess-9-337-2009
Furlan, P., Pfister, M., Matos, J., Amado, C., Schleiss, A.J. (2019). Experimental repetitions and blockage of large stems at ogee crested spillways with piers. Journal of Hydraulic Research, 57(2), 250-262. https://doi.org/10.1080/00221686.2018.1478897
Galloway, W.E., Hobday, D.K. (1996). Terrigenous Clastic Depositional Systems. Springer, Berlin Heidelberg Germany, 423 pp. https://doi.org/10.1007/978-3-642-61018-9
Gschnitzer, T., Gems, B., Mazzorana, B., Aufleger, M. (2017). Towards a robust assessment of bridge clogging processes in flood risk management. Geomorphology, 279, 128–140. https://doi.org/10.1016/j.geomorph.2016.11.002
Guerit, L., Métivier, F., Devauchelle, O., Lajeunesse, E., Barrier, L. (2014). Laboratory alluvial fans in one dimension. Physical Review E, 90, 022203. https://doi.org/10.1103/PhysRevE.90.022203
Hartmann, K., Krois, J., Waske, B. (2018). E- Learning Project SOGA: Statistics and Geospatial Data Analysis. Department of Earth Sciences, Freie Universität Berlin. https://www.geo.fu-berlin.de/en/v/soga/index.html
Hooke, R.L. (1968). Model Geology: Prototype and Laboratory Streams: Discussion. Geological Society of America Bulletin, 79(3), 391–394. https://doi.org/10.1130/0016-7606(1968)79[391:MGPALS]2.0.CO;2
Kienholz, H., Krummenacher, B., Kipfer, A., Perret, S. (2004). Aspects of integral risk management in practice: Considerations with respect to mountain hazards in Switzerland. Österreichische Wasser- und Abfallwirtschaft, 56(3), 43–50.
Lefever, D.W. (1926). Measuring Geographic Concentration by means of the Standard Deviational Ellipse. American Journal of Sociology, 32(1), 88–94. https://doi.org/10.1086/214027
Mazzorana, B., Simoni, S., Scherer, C., Gems, B., Fuchs, S., Keiler, M. (2014). A physical approach on flood risk vulnerability of buildings. Hydrology and Earth System Sciences, 18(9), 3817–3836. https://doi.org/10.5194/hess-18-3817-2014
Mazzorana, B., Ruiz-Villanueva, V., Marchi, L., Cavalli, M., Gems, B., Gschnitzer, T., Mao, L., Iroumé, A., Valdebenito, G. (2018). Assessing and mitigating large wood-related hazards in mountain streams: recent approaches. Journal of Flood Risk Management, 11(2), 207–222. https://doi.org/10.1111/jfr3.12316
Mazzorana, B., Ghiandoni, E., Picco, L. (2020). How do stream processes affect hazard exposure on alluvial fans? Insights from an experimental study. Journal of Mountain Science, 17(4), 753–772. https://doi.org/10.1007/s11629-019-5788-x
Moser, M. (2018). Physikalische Modellversuche zur Frage der Reproduzierbarkeit von Geschiebetransportprozessen am Schwemmkegel eines Wildbaches. Mater thesis. Unit of Hydraulic Engineering, University of Innsbruck, 185 pp.
Muto, T., Steel, R.J., Swenson, J.B. (2007). Autostratigraphy: A framework norm for genetic stratigraphy. Journal of Sedimentary Research, 77(1–2), 2–12. https://doi.org/10.2110/jsr.2007.005
National Research Council (1996). Alluvial Fan Flooding. The National Academies Press, Washington, DC United States of America, 1-182. https://doi.org/10.17226/5364.
Nguyen, N.T., He, W., Zhu, Y., Lü, H. (2020). Influence of Calibration Parameter Selection on Flash Flood Simulation for Small to Medium Catchments with MISDc-2L Model. Water, 12(11), 3255. https://doi.org/10.3390/w12113255
Paola, C., Straub, K., Mohrig, D., Reinhardt, L. (2009). The “unreasonable effectiveness” of stratigraphic and geomorphic experiments. Earth-Science Reviews, 97, 1-43. https://doi.org/10.1016/j.earscirev.2009.05.003
Reitz, M.D., Jerolmack, D.J. (2012). Experimental alluvial fan evolution: Channel dynamics, slope controls, and shoreline growth. Journal of Geophysical Research - Earth Surface, 117, F02021, https://doi.org/10.1029/2011JF002261.
Röthlisberger, V., Zischg, A.P., Keiler, M. (2017). Identifying spatial clusters of flood exposure to support decision making in risk management. Science of the Total Environment, 598, 593–603. https://doi.org/10.1016/j.scitotenv.2017.03.216
Santibañez, N., Mazzorana, B., Iribarren, P., Rojas, I., Mao, L. (2021). Dinámica distributiva de flujos bifásicos con carga de madera en un abanico aluvial experimental. Ingenieria del Agua, 25(2), 145-168. https://doi.org/10.4995/ia.2021.14703
Schalko, I. (2017). Large wood accumulation probability at a single bridge pier. In Ghani (Editor), Proceedings of the 37th IAHR world congress. Kuala Lumpur, Malaysia: IAHR and Usains Holding SDN BHD, 1704-1713.
Sturm, M., Gems, B., Keller, F., Mazzorana, B., Fuchs, S., Papathoma-Köhle, M., Aufleger, M. (2018a). Experimental analyses of impact forces on buildings exposed to fluvial hazards. Journal of Hydrology, 565, 1–13. https://doi.org/10.1016/j.jhydrol.2018.07.070
Sturm, M., Gems, B., Keller, F., Mazzorana, B., Fuchs, S., Papathoma-Köhle, M., Aufleger, M. (2018b). Understanding impact dynamics on buildings caused by fluviatile sediment transport. Geomorphology, 321, 45–59. https://doi.org/10.1016/j.geomorph.2018.08.016
Van Dijk, M., Postma, G., Kleinhans, M.G. (2009). Autocyclic behaviour of fan deltas: an analogue experimental study. Sedimentology, 56(5), 1569–1589. https://doi.org/10.1111/j.1365-3091.2008.01047.x
Van Dijk, M., Postma, G., Kleinhans, M.G., Kraal, E. (2012). Contrasting morphodynamics in alluvial fans and fan deltas: effect of the downstream boundary. Sedimentology, 59(7), 2125–2145. https://doi.org/10.1111/j.1365-3091.2012.01337.x
Wagenaar, D.J., De Bruijn, K.M., Bouwer, L.M., De Moel, H. (2016). Uncertainty in flood damage estimates and its potential effect on investment decisions. Natural Hazards and Earth System Sciences, 16(1), 1–14. https://doi.org/10.5194/nhess-16-1-2016
Whipple, K.X., Parker, G., Paola, C., Mohrig, D. (1998). Channel dynamics, sediment transport, and the slope of alluvial fans: Experimental study. Journal of Geology, 106(6), 677–693. https://doi.org/10.1086/516053
Yuill, R.S. (1971). The Standard Deviational Ellipse; An Updated Tool for Spatial Description. Geografiska Annaler: Series B, Human Geography, 53(1), 28–39. https://doi.org/10.1080/04353684.1971.11879353
