FLOOD HYDRAULICS DUE TO EMERGENT VEGETATION ALONG A RIPARIAN ZONE IN MEANDERING CHANNELS

Zulkiflee Ibrahim, Zulhilmi Ismail, Sobri Harun, Koji Shiono, Nazirah Mohd. Zuki, Md. Ridzuan Makhtar, Mazlin Jumain, Mohd. Suhaimi Abd. Rahman, Mohamad Hidayat Jamal

Abstract


Frequent floods around the globe including recent events in several states in Malaysia have damaged the residential properties, infrastructures and crops or even deaths. Clearing vegetations or trees on the floodplain has been pointed out as a contributing factor to the damages. Thus, the influence of floodplain vegetation on the river hydraulics during flooding must be better understood. The hydraulics of flood flows in non-erodible vegetated meandering channel was experimented in the laboratory where two-lined steel rods were installed along a riparian zone to simulate as trees. The stage-discharge relationship, flow resistance, depth-averaged velocity, streamwise vorticity and boundary shear stress patterns during shallow and deep flood inundations were studied. The findings showed that floodplain vegetation had increased the channel flow depth by 32% and its flow resistance. The velocity in vegetated zone was lowered and the shear stress reduced by 86.5% to 91% along the river meander. In addition, the trees also limit flow interaction between main channel and floodplain

Keywords


Physical modeling; laboratory experiment; meandering channel; floodplain vegetation; flood hydraulics

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References


United Nation Office for Disaster Reduction (UNISDR). 2014. Malaysia: Disaster and Risk Profile. www.preventionweb.net/countries/mys/data.

Leopold, L.B. and M.G. Wolman. 1957. River Channel Patterns: Braided, Meandering and Straight. U.S. Geological Survey Professional Paper 282-B. 39-85.

Ibrahim, Z., Z. Ismail, S. Harun, N.M. Kalimuddin, M.R. Makhtar, and T.N.T. Yunus. 2012. Flood Flow Characteristics in Non-Vegetated Meandering Channel: A Flume Simulation. Proc. International Conference on Water Resources (ICWR 2012), Langkawi. 5-6 November 2012. 31-39.

Ibrahim, Z. 2015. Flow Behaviour Due to Floodplain Roughness Along Riparian Zone in Compound Channels. Universiti Teknologi Malaysia. PhD Thesis.

Myers, W.R.C., D.W. Knight, J.F. Lyness, J.B. Cassells, and F. Brown. 1999. Resistance Coefficients for Inbank and Overbank Flows. Proc. Instn. Wat. Marit. & Energy, 136(6): 105-115.

Ismail, Z. and K. Shiono. 2006. The Effect of Vegetation Along Cross-Over Floodplain Edges on Stage-Discharge, Sediment Transport Rates in Compound Meandering Channels. Proc. of 5th WSEAS Int. Conf. on Env. Ecosystem & Development. Venice. 407-412.

Ismail, Z. and K. Shiono. 2007. The Behaviour of Stage-Discharge, Flow Resistance and Sediment Transport Influenced by Floodplain Roughness. 5th Int. Symp. on Environmental Hydraulics, Arizona, USA. CD ROM.

Ismail, Z. 2007. A Study of Overbank Flows in Non-Vegetated and Vegetated Floodplains in Compound Meandering Channels. Ph.D Thesis, Loughborough University, U.K.

Jahra, F., H. Yamamoto, R. Tsubaki, and Y. Kawahara. 2010. Turbulent Flow Structure in Meandering Vegetated Open Channel. River Flow 2010. 153-161.

Sun, X. and K. Shiono. 2009. Flow Resistance of One-Line Emergent Vegetation Along the Floodplain Edge of a Compound Open Channel. Journal in Advances Water Resources. 32(3): 430-438.

Nortek AS. 2004. Vectrino Velocimeter User Guide.

Patel, V.C. 1965. Calibration of Preston Tube and Limitations on Its Use in Pressure Gradients. Journal Fluid Mech. 23: 185-208.

Preston, J.H. 1954. The Determination of Turbulent Skin Friction by Means of Pitot Tubes. Journal of the Royal Aeronautical Society. 14: 109-121.

Sutardi 2003. Preston Tube Measurement: The Simplest Method to Estimate Wall Shear Stress. Jurnal Teknik Mesin. 3(2): 31-38.

Chow, V.T. 1959. Open Channel Hydraulics. Singapore: McGraw-Hill.

Sturm, T.W. 2001. Open Channel Hydraulics. Singapore: McGraw Hill.

Willetts, B.B. and P. Rameshwaran. 1996. Meandering Overbank Flow Structures. In Ashworth, Bennett, Best and McLelland (eds.). Coherent Flow Structures in Open Channel. New York: John Wiley and Sons. 609-629.

Shiono, K., J. Spooner, T. Chan, P. Rameshwaran, and J. H. Chandler. 2008. Flow Characteristics in Meandering Channels with Non-Mobile and Mobile Beds for Overbank Flows. Journal of Hydraulic Research. 46(1): 113-132.

Ismail, Z., Z. Ibrahim, and S. Harun. 2011. Inbank and Overbank Flows Characteristics in a Non-Vegetated Meandering Channel. Proc. Seminar Penyelidikan Kejuruteraan Awam (SEPKA 2011) UTM Johor Bahru. 13-15 September 2011. 114-119.

Tang, X. and D.W. Knight. 2009. Analytical Models for Velocity Distributions in Open Channel Flows. Journal of Hydraulic Research. 47(4): 418-428.

Sanjou, M. and I. Nezu. 2009. Turbulence Structure and Coherent Motion in Meandering Compound Open Channel Flows. Journal of Hydraulic Research. 47(5): 598-610.

Tominaga, A. and I. Nezu. 1991. Turbulent Structure in Compound Open Channels. Journal of Hydraulic Engineering. 117(1): 21-41.

Willetts, B.B. and R.I. Hardwick. 1993. Stage Dependency for Overbank Flow in Meandering Channels. Proc. Instn. Civ. Engrs. Wat. Marit. & Energy. 101(3): 45-54.

Muto, Y. and T. Ishigaki. 1999. Secondary Flow in Compound Sinuous/Meandering Channels. In Rodi, W. and D. Laurence, D. (eds.) Engineering Turbulence Modelling and Experiments –4. Elsevier Science Ltd. 511-520.

Naish, C. and R.H.J. Sellin. 1996. Flow Structure in a Large-Scale Model of a Doubly Meandering Compound River Channel. In Ashworth, Bennett, Best and McLelland (Eds.). Coherent Flow Structures in Open Channel. New York: John Wiley and Sons. 631-654.

Sun, X., K. Shiono, P. Rameshwaren, and J.H. Chandler. 2010. Modelling Vegetation Effects in Irregular Meandering River. Journal of Hydraulic Research. 48(6): 775-783.




DOI: http://dx.doi.org/10.11113/jt.v78.9703

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