Title

Compound Flooding in Convergent Estuaries: Insights from an Analytical Model

Document Type

Article

Publication Date

8-2022

DOI

10.5194/os-18-1203-2022

Publication Title

Ocean Science Discussions

Volume

18

Issue

4

Pages

1203-1220

Abstract

We investigate here the effects of geometric properties (channel depth and cross-sectional convergence length), storm surge characteristics, friction, and river flow on the spatial and temporal variability of compound flooding along an idealized, meso-tidal coastal-plain estuary. An analytical model is developed that includes exponentially convergent geometry, tidal forcing, constant river flow, and a representation of storm surge as a combination of two sinusoidal waves. Nonlinear bed friction is treated using Chebyshev polynomials and trigonometric functions, and a multi-segment approach is used to increase accuracy. Model results show that river discharge increases the damping of surge amplitudes in an estuary, while increasing channel depth has the opposite effect. Sensitivity studies indicate that the impact of river flow on peak water level decreases as channel depth increases, while the influence of tide and surge increases in the landward portion of an estuary. Moreover, model results show less surge damping in deeper configurations and even amplification in some cases, while increased convergence length scale increases damping of surge waves with periods of 12–72 h. For every modeled scenario, there is a point where river discharge effects on water level outweigh tide/surge effects. As a channel is deepened, this cross-over point moves progressively upstream. Thus, channel deepening may alter flood risk spatially along an estuary and reduce the length of a river estuary, within which fluvial flooding is dominant.

Comments

This work is distributed under the Creative Commons Attribution 4.0 License.

© Author(s) 2022.

ORCID

0000-0003-3374-7891 ( Familkhalili)

Original Publication Citation

Familkhalili, R., Talke, S. A., & Jay, D. A. (2022). Compound flooding in convergent estuaries: insights from an analytical model. Ocean Science, 18(4), 1203-1220. https://doi.org/10.5194/os-18-1203-2022

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