Laboratory study The effect of rack geometry on the efficiency of debris trapping and backwater

Document Type : Original Article

Authors

1 Department of Water Engineering, Faculty of Agriculture, Shahid Bahonar University of Kerman, Kerman, Iran

2 Department of Water Engineering, Faculty of Agriculture, Shahid Bahonar University of Kerman, Kerman, Iran;

Abstract

Accumulation of Debris in streams behind structures and bridge piers leads to the decrease of flow capacity, disruption of the discharge-scale relationship of control points and a negative impact on the performance and function of water structures. The use of rack structures is a common method of controlling debris. In this research, increasing the efficiency of the rack structure by redesigning this structure and also the amount of backwater behind this structure has been investigated. In these experiments, four types of rack geometry, three group of wood debris were investigated in the conditions of supercritical, critical and subcritical flow. Based on the results, the type of debris and flow conditions were ineffective in the efficiency of the rack and the best performance of the rack was the W-shaped rack with95% efficiency.However,the geometry of the rack and the flow conditions have affected the backwater in upstream, the v-shaped rack has created the lowest backwater with 0.14 %. except the geometry of the structure, the froude number of flow has affected the backwater.

Keywords

References

نوری، الف. 1391 بررسی حرکت جسم شناور در رودخانه با استفاده از روش SPH. پایان نامه کارشناسی ارشد رشته سازه‌های آبی، دانشکده عمران و محیط زیست، دانشگاه تربیت مدرس.
Bezzola, G.R. and Hegg, C. 2007. Ereignisanalyse Hochwasser 2005. Bundesamt für Umwelt, BAFU.
Braudrick, C.A. and Grant, G.E. 2001. Transport and deposition of large woody debris in streams: a flume experiment. Geomorphology. 41(4): 263-83
Brooks, A.P., Gehrke, P.C., Jansen, J.D. and Abbe, T.B. 2004. Experimentalreintroduction of woody debris on the Williams River. NSW, geomorphic and ecologicalresponses. River Research and Applications. 20(5): 513-536.
Bocchiola, D., Rulli, M.C. and Rosso, R. 2005. Flume experiments on wood entrainment in rivers. Advances in Water Resources. 29(8): 1182-1195.
Carey, G.R. 2018. Back-analysis study of selected Norwegian debris flow and debrisavalanche events (Master's thesis).
De Cicco, P.N., Paris, E.N.I.O., and Solari, L.U.C.A. 2015. Flume experiments on bridge clogging by woody debris: the effect of shape of piers. In 36th IAHR World Congress, The Hague, The Netherlands, Conference Proceedings.
Diehl, T.H. 1997. Potential drift accumulation at bridges. US Department of Transportation, Federal Highway Administration, Research and Development, Turner-Fairbank Highway Research Center.
Gippel, C.J. 1995. Environmental hydraulics of large woody debris in streams and rivers. Journal of Environmental Engineering. 121(5): 388-395.
Glade, T. 2005. Linking debris-flow hazard assessments with geomorphology. Geomorphology. Mar1; 66(1-4): 189-213.
Hartlieb, A. 2017. Decisive parameters for backwater effects caused by floating debris jams.
Kaitna, R. and Rickenmann, D. 2007. A new experimental facility for laboratory debris flow investigation. Journal of Hydraulic Research. 45(6): 797-810.
Josiah, N.R., Tissera, H.P.S., and Pathirana, K.P.P.2016. An experimental investigation of head loss through trash racks in conveyance systems. Engineer. 49(1): 1-8.
Liu, X. and Lei, J. 2003. A method for assessing regional debris flow risk. An application in Zhaotong of Yunnan province SW China. Geomorphology. 52(34): 181-191.
Mazzorana, B., Hübl, J., Zischg, A. and Largiader, A. 2011. Modelling woody material transport and deposition in alpine rivers. Natural Hazards. 56(2): 425-449.
Mizuyama, T. 2008. Structural countermeasures for debris flow disasters. International Journal of Erosion Control Engineering. 1(2): 38-43.
Rimböck, A. 2003. Schwemmholzrückhaltinwildbächen. Driftwood retention in mountain torrents. Doctoral dissertation, Ph.D. thesis, Technical University of Munich, Munich, Germany.
Schmocker, L. and Weitbrecht, V. 2013. Driftwood: Risk analysis and engineering measures. Journal of Hydraulic Engineering. 139(7): 683-695‏.
Schmocker, L. and Hager, W.H. 2013. Scale modeling of wooden debris accumulation at a debris rack. Journal of Hydraulic Engineering. 139(8): 827-36
Schalko, I. 2020. Wood retention at inclined racks: Effects on flow and local bedload processes. Earth Surface Processes and Landforms.
Schalko, I., Schmocker, L., Weitbrecht, V. and Boes, R.M. 2020. Laboratory study on wood accumulation probability at bridge piers. Journal of Hydraulic Research. 58(4): 566-581.
Schalko, I. 2018. Modeling hazards related to large wood in rivers (Doctoral dissertation, ETH Zurich).
Steeb, N., Rickenmann, D., Badoux, A., Rickli, C. and Waldner, P. 2017. Large wood recruitment processes and transported volumes in Swiss mountain streams during the extreme flood of August 2005. Geomorphology. 279: 112-127.
Wohl, E. and Jaeger, K. 2009. A conceptual model for the longitudinal distribution of wood in mountain streams. Earth Surface Processes and Landforms, 34(3): 329-344.
Iranian Journal of Irrigation & Drainage
Volume 14, Issue 5 - Serial Number 83
January and February 2021
Pages 1602-1612

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