3D-numerical modelling of cohesive suspended sediment in the Western Scheldt estuary (The Netherlands)

Abstract

A cohesive sediment transport model considering the effects of flocculation, deposition and erosion is used in an attempt to simulate the suspended sediment distribution in a mesotidal estuary. The numerical model solves the three-dimensional (30) advection-diffusion equation using a two-time level scheme, and a semi-implicit finite difference approach. The transport model is coupled to a 3D-barotropic hydrodynamic model for the simulation of the major tidal components reproducing the non-linear effects. An application of these models in the Western Scheldt estuary is described. The results of the different tests show that the adopted approach provides a useful basis for a good understanding of the physical processes involved in sediment transport and for the study of practical problems. The sensitivity of the model to key parameters controlling the simulation of bed sediment/water exchanges, shows the importance of a good definition of bottom sediment characteristics and the importance of further development of a consolidation algorithm.

Spatial heterogeneity in estuarine mud dynamics

“…Suspended particulate matter (SPM) settles when turbulent kinetic energy decreases. Depending on the concentration of SPM, particles may either deposit on the bed or-caused by hindered settling-may form mobile high concentration suspensions near the bed, which eventually become static and continue to settle until they consolidate and form a stable settled mud (Cancino and Neves 1994).…”

“…Such models can also support estuarine management, for example to predict the effects of dredging and dumping of sediment, harbour and fairway extensions, and creation or removal of intertidal areas. However, the models have been typically applied over a spring-neap cycle (e.g., Teisson 1991;Cancino and Neves 1994;Le Normant 2000;Widdows et al 2004;Waeles et al 2007), rather than a scale of months or years (Lumborg and Windelin 2003). Simulation of at least 1 year with high temporal and spatial resolution would capture the (semi-) diurnal, fortnightly and seasonal cycles that combine to determine the mud exchange within an estuary.…”

Variational inverse parameter estimation in a cohesive sediment transport model: An adjoint approach

“…Sheng [1986] presented a comprehensive sediment dispersion model coupled with a boundary layer. Cancino and Neves [1994] used a three‐dimensional cohesive sediment transport model to simulate the suspended sediment distribution in a mesotidal estuary. Their model included the effects of flocculation, deposition, and erosion processes.…”

Avaliação da correlação entre parâmetros de qualidade da água e socioeconômicos no Complexo Estuarino de Santos - São Vicente, através de modelagem numérica ambiental

“…Desde a década de 90, o rápido desenvolvimento da capacidade de cálculo computacional vem permitindo a resolução mais rigorosa de um número cada vez maior de problemas que envolvem o transporte de sedimentos (Cancino & Neves, 1994;Portela & Neves, 1994), a qualidade da água e a ecologia (Portela & Neves, 1995 Neves (1985) como um modelo hidrodinâmico bidimensional. Neves (2007) descreveu a evolução deste modelo para um sistema de modelos integrados de fluxo de marés em estuários, ondas (Silva, 1991), qualidade da água (Portela, 1996), escoamentos tridimensionais (Santos, 1995), para novos métodos numéricos (Martins et al, 2000), com diferentes condições de contorno aberto (Leitão, 2003), até finalmente ser reorganizado em uma perspectiva integrada, a fim de acomodar também módulos alternativos para diferentes processos (Braunschweig et al, 2004), como os módulos que simulam processos biogeoquímicos e processos de qualidade da água (Trancoso et al, 2005;Saraiva et al, 2006;Mateus, 2006), fluxos de água em meios em meios porosos (Galvão et al, 2004), fluxos de água em bacias hidrográficas (Braunschweig & Neves, 2006) e a circulação oceânica (Leitão et al, 2006).…”