A global assessment of estuarine tidal response to sea level rise

Danial Khojasteh; Stefan Felder; Valentin Heimhuber; William Glamore

doi:10.1016/j.scitotenv.2023.165011

A global assessment of estuarine tidal response to sea level rise

Sci Total Environ. 2023 Oct 10:894:165011. doi: 10.1016/j.scitotenv.2023.165011. Epub 2023 Jun 21.

Authors

Danial Khojasteh¹, Stefan Felder², Valentin Heimhuber³, William Glamore⁴

Affiliations

¹ Water Research Laboratory, School of Civil and Environmental Engineering, UNSW Sydney, NSW, Australia. Electronic address: danial.khojasteh@unsw.edu.au.
² Water Research Laboratory, School of Civil and Environmental Engineering, UNSW Sydney, NSW, Australia. Electronic address: s.felder@unsw.edu.au.
³ Water Research Laboratory, School of Civil and Environmental Engineering, UNSW Sydney, NSW, Australia. Electronic address: v.heimhuber@unsw.edu.au.
⁴ Water Research Laboratory, School of Civil and Environmental Engineering, UNSW Sydney, NSW, Australia. Electronic address: w.glamore@wrl.unsw.edu.au.

PMID: 37353027
DOI: 10.1016/j.scitotenv.2023.165011

Abstract

Climate change induced sea level rise (SLR) is one of the greatest challenges threatening the sustainable management of estuaries worldwide. Current knowledge regarding SLR and estuarine hydrodynamics is primarily focused on individual case studies, which provides limited guidance on how different estuary typologies will respond to SLR. To expand the current knowledge, this research used an idealised hydrodynamic approach to analyse the tidal range dynamics of 25 real-world estuaries with diverse shapes and boundary conditions, providing insights into estuarine response to SLR-induced tidal variations. Under present-day conditions, short length estuaries with wide entrances, deep waters, strong convergence, macro-tidal conditions, low values of roughness, and low upland river inflows are likely to experience amplified tidal range patterns; whereas lengthy estuaries with narrow entrances, shallow water depths, micro/meso-tidal conditions, high values of roughness, and high upland river inflows often exhibit a mix of dampened-amplified or fully dampened tidal range patterns. Under the effects of SLR, estuarine tidal range dynamics change depending on their present-day tidal range patterns. Where the present-day tidal range pattern is either dampening, a mix of dampening/amplification, or amplification, SLR increases (up to 61 %), moderately increases (up to 26 %), and slightly decreases/increases (up to 5 %) the tidal range of estuaries, respectively. Considering the relationship between an estuary's present-day tidal range pattern and its response to SLR, the presented approach may be useful in providing an initial assessment of SLR effects in estuaries worldwide. This approach may also help to identify sites most impacted by future SLR, and to direct decision-making towards evidence-based management approaches.

Keywords: Climate change; Estuary; Flooding; Hydrodynamic modelling; Tidal inundation; Tide.