Linking the river to the estuary: influence of river discharge on tidal damping
The effect of river discharge on tidal damping in estuaries is explored within one consistent theoretical framework where analytical solutions are obtained by solving four implicit equations, i.e. the phase lag, the scaling, the damping and the celerity equation. In this approach the damping equatio...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2014-01-01
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| Series: | Hydrology and Earth System Sciences |
| Online Access: | http://www.hydrol-earth-syst-sci.net/18/287/2014/hess-18-287-2014.pdf |
| Summary: | The effect of river discharge on tidal damping in estuaries is explored
within one consistent theoretical framework where analytical solutions are
obtained by solving four implicit equations, i.e. the phase lag, the
scaling, the damping and the celerity equation. In this approach the damping
equation is obtained by subtracting the envelope curves of high water and low
water occurrence, taking into account that the flow velocity consists of
a tidal and river discharge component. Different approximations of the
friction term are considered in deriving the damping equation, resulting in
as many analytical solutions. In this framework it is possible to show that
river discharge affects tidal damping primarily through the friction term. It
appears that the residual slope, due to nonlinear friction, can have a
substantial influence on tidal wave propagation when including the effect of
river discharge. An iterative analytical method is proposed to include this
effect, which significantly improved model performance in the upper reaches
of an estuary. The application to the Modaomen and Yangtze estuaries
demonstrates that the proposed analytical model is able to describe the main
tidal dynamics with realistic roughness values in the upper part of the
estuary where the ratio of river flow to tidal flow amplitude is substantial,
while a model with negligible river discharge can be made to fit observations
only with unrealistically high roughness values. |
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| ISSN: | 1027-5606 1607-7938 |