The backwater effect as a tool to assess formative long-term flood regimes

Castelltort, F. Xavier; Castellet, Ernest Bladé i; Balasch, Josep Carles; Ribé, Martí

doi:10.1016/j.quaint.2020.01.012

Cited by 9 publications

(5 citation statements)

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“…9). In addition, the channel constriction in the Delaware River might also facilitate the formation of backwaters (Castelltort et al, 2020).…”

Section: Discharge Twl and Topologymentioning

confidence: 99%

“…The latter is more critical in low-lying mega-delta regions that reside over 0.5 billion people globally (Syvitski and Saito, 2007). Streamflow in the backwater zones is affected by river topology, upstream discharge, sea level variations and their interactive effects (Castelltort et al, 2020;Hellmers and Fröhle, 2022). Specifically, river topology is characterized by the river channel geometry, riverbed elevation and the river's receiving water body.…”

Section: Introductionmentioning

confidence: 99%

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

Feng

Tan

Engwirda

et al. 2022

Hydrol. Earth Syst. Sci.

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Abstract. Coastal backwater effects are caused by the downstream water level increase as a result of elevated sea level, high river discharge and their compounding influence. Such effects have crucial impacts on floods in densely populated regions but have not been well represented in large-scale river models used in Earth system models (ESMs), partly due to model mesh deficiency and oversimplifications of river hydrodynamics. Using two mid-Atlantic river basins as a testbed, we perform the first attempt to simulate the backwater effects comprehensively over a coastal region using the MOSART river transport model under an ESM framework, i.e., Energy Exascale Earth System Model (E3SM) configured on a regionally refined unstructured mesh, with a focus on understanding the backwater drivers and their long-term variations. By including sea level variations at the river downstream boundary, the model performance in capturing backwaters is greatly improved. We also propose a new flood event selection scheme to facilitate the decomposition of backwater drivers into different components. Our results show that while storm surge is a key driver, the influence of extreme discharge cannot be neglected, particularly when the river drains to a narrow river-like estuary. Compound flooding, while not necessarily increasing the flood peaks, exacerbates the flood risk by extending the duration of multiple coastal and fluvial processes. Furthermore, our simulations and analysis highlight the increasing strength of backwater effects due to sea level rise and more frequent storm surge during 1990–2019. Thus, backwaters need to be properly represented in ESMs to improve the predictive understanding of coastal flooding.

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“…9). In addition, the channel constriction in the Delaware River might also facilitate the formation of backwaters (Castelltort et al, 2020).…”

Section: Discharge Twl and Topologymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Feng

Tan

Engwirda

et al. 2022

Hydrol. Earth Syst. Sci.

View full text Add to dashboard Cite

show abstract

“…9). In addition, the channel constriction in Delaware River might also facilitate the formation of backwaters (Castelltort et al, 2020).…”

Section: Discharge Twl and Topologymentioning

confidence: 99%

“…However, the interactions among the backwater drivers and their respective contributions through fluvial processes, storm and climate are not well understood (Dykstra & Dzwonkowski, 2021). Streamflow in the backwater zones is affected by river topology, upstream discharge, sea level variations and their interactive effects (Castelltort et al, 2020;Hellmers & Fröhle, 2022). Specifically, river topology is characterized by the river channel geometry, riverbed elevation and river's receiving water body.…”

Section: Introductionmentioning

confidence: 99%

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

Feng

Tan

Engwirda

et al. 2022

Preprint

View full text Add to dashboard Cite

Abstract. Coastal backwater effects are caused by the downstream water level increase as the result of elevated sea level, high river discharge and their compounding influence. Such effects have crucial impacts on floods in densely populated regions but have not been well represented in large-scale river models used in Earth System Models (ESMs), partly due to model mesh deficiency and oversimplifications of river hydrodynamics. Using two mid-Atlantic river basins as a testbed, we perform the first attempt to simulate the backwater effects comprehensively over a coastal region using the MOSART river transport model under an Earth system model framework i.e., Energy Exascale Earth System Model (E3SM) configured on a regionally-refined unstructured mesh, with a focus on understanding the backwater drivers and their long-term variations. By including sea level variations at the river downstream boundary, the model performance in capturing backwaters is greatly improved. We also propose a new flood event selection scheme to facilitate the decomposition of backwater drivers into different components. Our results show that while storm surge is a key driver, the influence of extreme discharge cannot be neglected, particularly when the river drains to a narrow river-like estuary. Compound flooding, while not necessarily increasing the flood peaks, exacerbates the flood risk by extending the duration of multiple coastal and fluvial processes. Furthermore, our simulations and analysis highlight the increasing strength of backwater effects due to sea level rise and more frequent storm surge during 1990–2019. Thus, backwaters need to be properly represented in ESMs for improving predictive understanding of coastal flooding.

show abstract

“…Numerical simulation is one of the tools used by Elleder et al ( 2020) for characterizing a single and well defined extreme event, while in the paper by Castelltort et al (2020) the hydraulic modeling is a core topic that was developed for investigating the long-term evolution of a fluvial channel. They studied a tract of the Tar River in the region of Catalonia (Iberian Peninsula), where the main stream receives the contribution from the Gurri River, immediately before a bedrock constriction.…”

mentioning

confidence: 99%