A Novel Framework for Parametric Analysis of Coastal Transition Zone Modeling

Abstract

Vulnerability of coastal regions to extreme events motivates an operational coupled inland‐coastal modeling strategy focusing on the coastal transition zone (CTZ), an area between the coast and upland river. To tackle this challenge, we propose a top‐down framework for investigating the contribution of different processes to the hydrodynamics of CTZs with various geometrical shapes, different physical properties, and under several forcing conditions. We further propose a novel method, called tidal vanishing point (TVP), for delineating the extent of CTZs through the upland. We demonstrate the applicability of our framework over the United States East and Gulf coasts. We categorize CTZs in the region into three classes, namely, without estuary (direct river–coast connection), triangular‐, and trapezoidal‐shaped estuary. The results show that although semidiurnal tidal constituents are dominant in most cases, diurnal tidal constituents become more prevalent in the river segment as the discharge increases. Also, decreasing the bed roughness value promotes more significant changes in the results than increasing it by the same value. Additionally, the estuary promotes tidal energy attenuation and consequently decreases the reach of tidal signals through the upland. The proposed framework is generic and extensible to any coastal region.

Simulation of Compound Flooding Using River‐Ocean Two‐Way Coupled E3SM Ensemble on Variable‐Resolution Meshes

“…However, the determination of river‐ocean boundaries in various estuaries must be made locally. Considering the number of rivers globally and the change of geomorphological features over time, it is unrealistic to adjust the boundary for every river in ESMs, which requires the specification of different types of boundary conditions or coupling strategies (Chegini et al., 2022). This marks a crucial demand in our ongoing efforts to advance ESMs for better modeling of coastal processes.…”

Investigating coastal backwater effects and flooding in the coastal zone using a global river transport model on an unstructured mesh

“…Since rivers contribute to a variety of water bodies including deltaic floodplains, estuaries and coastal oceans (Mikhailov and Gorin, 2012), the interactive effects of river discharge and sea level vary substantially. For example, the impact of river discharge on the local sea level is much more intense in a narrow tidal-river estuary than in an open sea (Rayson et al, 2015;Chegini et al, 2022). In a narrow estuary, flood risks are further exacerbated because high discharge increases the local sea level, high sea level induced by storm surge impedes river discharge to the ocean, and the interaction of these two mechanisms intensifies the backwater effects (Eilander et al, 2020).…”

Investigating coastal backwater effects and flooding in the coastal zone using a global river transport model on an unstructured mesh

“…As rivers contribute to a variety of water bodies including deltaic floodplains, estuaries and coastal oceans (Mikhailov & Gorin, 2012), the interactive effects of river discharge and sea level vary substantially. For example, the impact of river discharge on the local sea level is much more intense in a narrow tidal-river estuary than in an open sea (Rayson et al, 2015;Chegini et al, 2022). In a narrow estuary, flood risks are further exacerbated because high discharge increases the local sea level, high sea level induced by storm surge impedes river discharge to the ocean, and the interaction of these two mechanisms intensifies the backwater effects (Eilander et al, 2020).…”