Numerical experiments to investigate the effects of quadratic friction on the propagation of tides in a channel

Godin, Gabriel; Martínez, Ana Cristina Lahuerta

doi:10.1016/0278-4343(94)90070-1

Cited by 54 publications

(56 citation statements)

References 20 publications

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“…That junction connects a very deep and short sea-connected southern branch to a much smaller northern branch, which bifurcates once more in two equally long branches. The large tidal impact observed may relate to water level setup caused by river-tide interaction in the (Godin and Martinez 1994;Buschman et al 2009). The southern channel conveys a larger share of the river discharge, resulting in a tendency to generate a subtidal water level setup, as shown in Fig.…”

Section: Tidal Impact On Discharge Divisionmentioning

confidence: 93%

Tidal impact on the division of river discharge over distributary channels in the Mahakam Delta

et al. 2011

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Bifurcations in tidally influenced deltas distribute river discharge over downstream channels, asserting a strong control over terrestrial runoff to the coastal ocean. Whereas the mechanics of river bifurcations is well-understood, junctions in tidal channels have received comparatively little attention in the literature. This paper aims to quantify the tidal impact on subtidal discharge distribution at the bifurcations in the Mahakam Delta, East Kalimantan, Indonesia. The Mahakam Delta is a regular fan-shaped delta, composed of a quasi-symmetric network of rectilinear distributaries and sinuous tidal channels. A depth-averaged version of the unstructured-mesh, finite-element model second-generation Louvain-la-Neuve Ice-ocean Model has been used to simulate the hydrodynamics driven by river discharge and tides in the delta channel network. The model was forced with tides at open sea boundaries and with measured and modeled river discharge at upstream locations. Calibration was performed with water level time series and flow measurements, both spanning a simulation period. Validation was performed by comparing the model results with discharge measurements at the two principal bifurcations in the delta. Results indicate that within 10 to 15 km from the delta apex, the tides alter the river discharge division by about 10% in all bifurcations. The tidal impact increases seaward, with a maximum value of the order of 30%. In general, the effect of tides is to hamper the discharge division that would occur in the case without tides.

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Section: Tidal Impact On Discharge Divisionmentioning

confidence: 93%

Tidal impact on the division of river discharge over distributary channels in the Mahakam Delta

et al. 2011

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“…In the non-linear terms appear the products of two unknowns, u (velocity) and/or z (level): Godin and Martinez 1994), u| u | being more significant, since in general z H \1: 2. Advective term:u @u @x ¼ @ @x u 2 2 ;…”

Section: And M Sf Generation: Theoretical Analysismentioning

confidence: 99%

“…The product u| u | is considered as a sum of two odd terms of u,u u j j % 0:35u þ 0:71u 3 À Á according to Godin and Martinez (1994); Godin (1999); Gallo (2004). Replacing Eqs.…”

Section: And M Sf Generation: Theoretical Analysismentioning

confidence: 99%

Generation of overtides and compound tides in Amazon estuary

2005

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Tidal propagation in estuaries is affected by friction and fresh water discharge, besides changes in the depth and morphology of the channel. Main distortions imply variations in the mean water level and asymmetry. Tidal asymmetry can be important as a mechanism for sediment accumulation and turbidity maximum formation in estuaries, while mean water level changes can affect navigation depths. Data from several gauges stations from the Amazon estuary and the adjacent coast were analyzed and a 2DH hydrodynamic model was configured in a domain covering the continental shelf up to the last section of the river where the tidal signature is observed. Based on data, theoretical and numerical results, the various influences in the generation of estuarine harmonics are presented, including that of fresh water discharge. It is shown that the main overtide, M 4 , derived from the most important astronomic component in the Amazon estuary, M 2 , is responsible for the tidal wave asymmetry. This harmonic has its maximum amplitude at the mouth, where minimum depths are found, and then decreases while tide propagates inside the estuary. Also, the numerical results show that the discharge does not affect water level asymmetry; however, the Amazon river discharge plays an important role in the behavior of the horizontal tide. The main compound tide in Amazon estuary, Msf, generated from the combination of the M 2 and S 2 , can be strong enough to provoke neap low waters lower than spring ones. The results show this component increasing while going upstream in the estuary, reaching a maximum and then slightly decaying.

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“…LeBlond, 1979;Godin and Martinez, 1994;Buschman et al, 2009;Sassi and Hoitink, 2013) and the density gradient (e.g. Savenije, 2005Savenije, , 2012.…”

Section: Introductionmentioning

confidence: 99%

Analytical approach for determining the mean water level profile in an estuary with substantial fresh water discharge

Cai

Savenije

Jiang

et al. 2016

Hydrol. Earth Syst. Sci.

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Abstract.The mean water level in estuaries rises in the landward direction due to a combination of the density gradient, the tidal asymmetry, and the backwater effect. This phenomenon is more prominent under an increase of the fresh water discharge, which strongly intensifies both the tidal asymmetry and the backwater effect. However, the interactions between tide and river flow and their individual contributions to the rise of the mean water level along the estuary are not yet completely understood. In this study, we adopt an analytical approach to describe the tidal wave propagation under the influence of substantial fresh water discharge, where the analytical solutions are obtained by solving a set of four implicit equations for the tidal damping, the velocity amplitude, the wave celerity, and the phase lag. The analytical model is used to quantify the contributions made by tide, river, and tide-river interaction to the water level slope along the estuary, which sheds new light on the generation of backwater due to tide-river interaction. Subsequently, the method is applied to the Yangtze estuary under a wide range of river discharge conditions where the influence of both tidal amplitude and fresh water discharge on the longitudinal variation of the mean tidal water level is explored. Analytical model results show that in the tide-dominated region the mean water level is mainly controlled by the tide-river interaction, while it is primarily determined by the river flow in the river-dominated region, which is in agreement with previous studies. Interestingly, we demonstrate that the effect of the tide alone is most important in the transitional zone, where the ratio of velocity amplitude to river flow velocity approaches unity. This has to do with the fact that the contribution of tidal flow, river flow, and tide-river interaction to the residual water level slope are all proportional to the square of the velocity scale. Finally, we show that, in combination with extreme-value theory (e.g. generalized extremevalue theory), the method may be used to obtain a first-order estimation of the frequency of extreme water levels relevant for water management and flood control. By presenting these analytical relations, we provide direct insight into the interaction between tide and river flow, which will be useful for the study of other estuaries that experience substantial river discharge in a tidal region.

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Numerical experiments to investigate the effects of quadratic friction on the propagation of tides in a channel

Cited by 54 publications

References 20 publications

Tidal impact on the division of river discharge over distributary channels in the Mahakam Delta

Tidal impact on the division of river discharge over distributary channels in the Mahakam Delta

Generation of overtides and compound tides in Amazon estuary

Analytical approach for determining the mean water level profile in an estuary with substantial fresh water discharge

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