Abstract
Settling velocity is one of the important parameters in sediment transport modeling of estuaries. The methods adopted for its determination vary from theoretical equations to experimental methods. The theoretical equation generally adopted in the 1DV model include assumptions in order to simplify the solution. It is generally assumed that either the condition is steady or the vertical diffusion is negligible. This study evaluated the relative importance of the two assumptions made for the estimation of settling velocity. Two approaches were adopted: unsteady and negligible vertical diffusion (NS-NVD) and steady with vertical diffusion (S-VD) to estimate the settling velocity. The Muthupet Estuary in the Coromandal coast of India was selected for the study. The S-VD approach estimated settling velocity fairly well at the two locations with appreciable vertical diffusion. The NS-NVD approach was observed to be superior for estimating settling velocity at shallow reaches of the estuary having low flow velocity. The calculated settling velocity was further applied in 1DV model to predict the suspended sediment concentration. The S-VD approach predicted suspended sediment concentration at those locations with appreciable vertical diffusion with an R2 value of 0.82 against 0.67 for the NS-NVD approach. At the other shallow reach of the estuary with low flow velocity, the NS-NVD approach gave an R2 value of 0.822 against 0.71 for the S-VD approach. The vertical diffusion was observed to play a secondary role at those locations which are shallow with a water depth of 0.6 m and with a low flow velocity of the order of 0.01 m/s. The study demonstrated that localized hydrodynamic conditions influence the method adopted for the estimation of settling velocity.
Similar content being viewed by others
References
Agrawal YC, Pottsmith HC (2000) Instruments for particle size and settling velocity observations in sediment transport. Mar Geol 168(1–4):89–114
Camp TR, Stein PC (1943) Velocity gradients and internal work in fluid motion. J Boston Soc Civil Eng 30:219–237
Fugate DC, Friedrichs CT (2002) Determining concentration and fall velocity of estuarine particle populations using ADV, OBS and LISST. Cont Shelf Res 22(11–13):1867–1886
Fugate DC, Friedrichs CT (2003) Controls on suspended aggregate size in partially mixed estuaries. Estuar Coast Shelf S 58(2):389–404
Ha HK, Maa JP-Y (2010) Effects of suspended sediment concentration and turbulence on settling velocity of cohesive sediment. Goesci J 14(2):163–171. doi:10.1007/s 12303-010-0016-2
Manning AJ, Bass SJ, Dyer KR (2006) Floc properties in the turbidity maximum of a mesotidal estuary during neap and spring tidal conditions. Mar Geol 235:193–211
Manning AJ, Martens C, De Mulder T, Vanlede J, Winterwerp JC, Ganderton P, Graham GW (2007) Mud floc observations in the turbidity maximum zone of the Scheldt estuary during neap tides. J Coastal Res SI 50:832–836
Maren DSV, Hoekstra P (2004) Seasonal variation of hydrodynamics and sediment dynamics in a shallow subtropical estuary: the Ba Lat River, Vietnam. Estuar Coast Shelf S 60:529–540
Masselink G, Cointre L, Williams J, Gehrels R, Blake W (2009) Tide-driven dune migration and sediment transport on an intertidal shoal in a shallow estuary in Devon, UK. Mar Geol 262:82–95. doi:10.1016/j.margeo.2009.03.009
Nowell ARM (1983) The benthic boundary layer and sediment transport. Rev Geophys 21:1181–1192
Orton PM, Kineke GC (2001) Comparing calculated and observed vertical suspended-sediment distributions from a Hudson River estuary turbidity maximum. Estuar Coast Shelf S 52:401–410
Owen MW (1976) Determination of the settling velocities of cohesive muds. Hydraulic Research Station, Wallingford, Hydraulics Res Rep No. IT 161, 8 p
Priya KL, Haddout S, Adarsh S (2018) Settling velocity of fine suspended sediments in Muthupet estuary, India and Bouregreg estuary, Morocco. In: Abstract of International Conference on Sustainable Technologies on Intelligent Water, Indian Institute of Technology Roorkee, India, 16–19 Feb 2018
Priya KL, Jegathambal P, James EJ (2012) Seasonal behaviour of a shallow estuary of the lower Cauvery basin, India. Environ Re 3(61):6–13
Priya KL, Jegathambal P, James EJ (2014) Trace metal distribution in a shallow estuary. Toxicol Environ Chem 96(4):579–593
Priya KL, Jegathambal P, James EJ (2015a) Seasonal dynamics of turbidity maximum in the Muthupet estuary, India. J Ocean U China 14(5):765–777
Priya KL, Jegathambal P, James EJ (2015b) On the factors affecting the settling velocity of fine suspended sediments in a shallow estuary. J Oceanogr 71(2):163–175
Priya KL, Jegathambal P, James EJ (2016) Salinity and suspended sediment transport in a shallow estuary on the east coast of India. Reg Stud Mar Sci 7:88–99
Rao VP, Shynu R, Kessarkar PM, Sundar D, Michael GS, Narvekar T, Blosson E, Mehra P (2011) Suspended sediment dynamics on a seasonal scale in the Mandovi and Zuari estuaries, central west coast of India. Estuar Coast Shelf S 91(1):78–86
Rouse H (1937) Modern conceptions of the mechanics of fluid turbulence. T Am Soc Civ Eng 102:463–541
Rouse H (1938) Experiments on the mechanics of sediment suspension. In: Proceedings of the Fifth International Congress for Applied Mechanics, John Wiley & Sons, New York, pp 550–554
Schlichting H (1979) Boundary-layer theory. McGraw-Hill, New York, 817 p
Shi JZ (2010) Tidal resuspension and transport processes of fine sediment within the river plume in the partially-mixed Changjiang river estuary, China: a personal perspective. Geomorphology 121:133–151
Shi Z, Zhou HJ (2004) Controls on the effective settling velocities of mud flocs in the Changjiang estuary, China. Hydrol Process 18:2877–2892
Shi Z, Zhou HJ, Eittreim SL, Winterwerp JC (2003) Settling velocities of fine suspended particles in the Changjiang estuary, China. J Asian Earth Sci 22:245–251
Simpson JH, Brown J, Matthews J, Allen G (1990) Tidal straining, density currents and stirring control of estuarine circulation. Estuaries 13(2):125–132
Spearman JR, Roberts W (2002) Comparison of flocculation models for applied sediment transport modeling. In: Winterwerp JC, Kranenburg C (eds) Fine sediment dynamics in the maine environment. Elsevier, Amsterdam, pp 277–293
van Leussen W, Cornelisse J (1992) The role of large aggregates in estuarine fine-grained sediment dynamics. In: Mehtha AJ (ed) Nearshore and estuarine cohesive sediment transport. American Geophysical Union, Washington DC, pp 75–91
van Leussen W (1994) Estuarine macroflocs and their role in fine grained sediment transport. Ph.D. Thesis, University of Utrecht, 488 p
Wolanski E, Gibbs R, Mazda Y, Mehta AJ, King B (1992) The role of buoyancy and turbulence in the settling of mud flocs. J Coastal Res 8(1):35–46
Xia XM, Li Y, Yang H, Wu CY, Sing TH, Pong HK (2004) Observations on the size and settling velocity distribution of suspended sediment in the Pearl river estuary, China. Cont Shelf Res 24(16):1809–1826
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Priya, K.L. Studies on the Application of Steady State Assumption in 1DV Model for the Estimation of Settling Velocity of Suspended Sediments in a Shallow Estuary. Ocean Sci. J. 53, 449–459 (2018). https://doi.org/10.1007/s12601-018-0035-x
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s12601-018-0035-x