Experimental Investigation of The Effect of Bed’s Coarse Gravel on the Deposition and Entrapment of Suspended Cohesive Sediment Process

Document Type : Research Article


1 Water Engineering Department, Ferdowsi University of Mashhad

2 Water Engineering Department, Ferdowsi University of Mashhad, Iran

3 Water Engineering Department , Shahrekord University, Iran


Bed material is one of the factors affecting the deposition and entrapping of cohesive sediments. In this work, entrapment of cohesive sediment in gravel bed (D50= 2.4 and 9.4 mm) and smooth bed was investigated using circular flume. For this purpose, the effect of gravel bed sediments on the entrapping and deposition of suspended sediments in different concentrations and different flow turbulence has been tested. The experiments were carried out in two modes of smooth and rough beds for initial concentrations of 5, 10 and 20 g/l and flow velocity 0.14, 0.24 and 0.34 m/s. The results showed that, in two modes of bed, the concentration of suspended sediments decreases with time, but the bed contains coarse sediment increases the amount of deposition rate and the time of reaching to an equilibrium concentration. The results also showed that the entrapping coefficient in bed containing sand and gravel beds was about 5.7 and 3.5 times more than that of smooth bed, respectively. Increasing the entrapping coefficient in larger shear stresses can be explained by the effect of coarse-grained bed sediments on reducing the flow velocity and generating bursting - sweep phenomena due to flow turbulence.


Amelia V.C.M., Teixeira, C.F.J., Senhorinha. Teixeira, F.C.F.S. (2010). “Physical characterization of estuarine sediments in the northern coast of Portugal”. Journal of Coastal Research, 26.2: 301-311.
Detert, M., Nikora, V., Jirka, G., (2010). “Synoptic velocity and pressure fields at the water-sediment interface of streambeds”. J. Fluid Mech. 660, 55–86.
Dwivedi, A., Melville, B., Shamseldin, A., Guha, T., (2011). “Flow structures and hydro- dynamic force during sediment entrainment”. Water Resour. Res. 47, W01509 . Finnigan, J. 20 0 0. Turbulence in plant canopies. Ann. Rev. Fluid Mech. 32 (1), 519–571
Giardino, A., Ibrahim, E., Adam, S., Toorman, E.A., Monbaliu, J. (2009). “Hydrodynamics and Cohesive sediment transport in the Ijzer Estuary, Belgium: Case Steady”. Journal of Waterway, Port, Coastal and Ocean Engineering (ACSE), 135:176-184.
Gonzalez. F.N. (2016). “Infiltration of fine sediment mixtures through poorly sorted immobile coarse beds”. Journal of Advances in Water Resources, AGU Puplication. 52, 9306–9324.
Heppell, C. , Wharton, G. , Cotton, J. , Bass, J., Roberts, S., (2009). “Sediment storage in the shallow hyporheic of lowland vegetated river reaches”. Hydrol. Processes 23, 2239–2251.
Huang, J., Hilldate, R.C., Greiman, B.P. (2006). “Erosion and sedimentation manual”. U.S. Department of the interior. United States Bureau of Reclamation.
Khastar Boroujeni, M., Esmaili, k., Samadi, H., Ziaei, A.N. (2018). “Wastewater effect on the deposition of cohesive sediment”. Journal of Environmental Engineering, ASCE, ISSN 0733-9372. 144(1): 04017083
Krishnappan, B.G. & Engel, P. (2006). Entrapment of fines in coarse sediment beds. River Flow 2006. Ferreira, Alves, Leal and Cardoso (eds). Taylor and Francis Group, London, 817–824.
Krone, R.B. (1962). "Flume Studies of the Transport of Sediment in Estuarial Shoaling Processes," Technical Report, Hydraulic Engineering Laboratory, University of California, Berkeley California.
Maa, J.P., Kwon, J., Hwang, K., Kyung Ha, H. 2008. Critical bed shear stress for cohesive sediment deposition under steady flows. Journal of Hydraulic Enigineering (ASCE), 134: 1767-1771.
Mehta, A.J., and E. Partheniades (1973). "Depositional Behavior of Cohesive Sediments," Tech Report No. 16, Univ. of Florida, Gainesville, Florida.
Mohajeri, S. H., Righetti , M., Wharton. G., Romano. G. P. (2016). “On the structure of turbulent gravel b e d flow: Implications for sediment transport”. Journal of Advances in Water Resources (Elsevier). 92 , 90–104.
Packman, A.I., and MacKay, J.S. (2003). “Interplay of stream-subsurface exchange, clayparticle deposition, and streambed evolution”. Water Resources Research. 39(4): 1-7.
Partheniades, E., and Kennedy, J. G. (1966). “Deposition behavior of fine sediment in a turbulent fluid motion”. Proc., 10th Int. Conf. on Coastal Engineering, Tokyo, 707–724.
Partheniades, E., Cross, R.H., Ayora, A., (1968). “Further research on the deposition of cohesive sediments”. Proceedings of the 11th Conference on Coastal Engineering, pp. 723–772.
Partheniades, E., J.F. Kennedy, R.J. Etter, and R.P. Hoyer (1966). “Investigations of the Depositional Behavior of Fine Cohesive Sediments in an Annular Rotating Channel.”, Hydrodynamics Lab Report No. 96, MIT, Cambridge Massachusetts.
Radice, A., Nikora, V., Campagnol, J., Ballio, F., (2013). “Active interactions between tur- bulence and bed load: Conceptual picture and experimental evidence”. Water Resour. Res. 49 (1), 90–99 .
Rehg, K.J., Packman, A.I., Ren, J. (2005). “Effects of suspended sediment characteristics andbed sediment transport on streambed clogging”. Hydrological Processes, 19: 413-427.
Winterwerp, J.C. (2007). On the sedimentation rate of cohisive sediment. Estuarine and Coastal Fine Sediments Dynamics, 209-225.