Combined Effect of Tides and Varying Inland Groundwater Input on Flow and Salinity Distribution in Unconfined Coastal Aquifers

Tides and seasonally varying inland freshwater input, with different fluctuation periods, are important factors affecting flow and salt transport in coastal unconfined aquifers. These processes affect submarine groundwater discharge (SGD) and associated chemical transport to the sea. While the indiv...

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Published in:Water Resources Research
Main Author: Kuan W.K.; Xin P.; Jin G.; Robinson C.E.; Gibbes B.; Li L.
Format: Article
Language:English
Published: Blackwell Publishing Ltd 2019
Online Access:https://www.scopus.com/inward/record.uri?eid=2-s2.0-85075153380&doi=10.1029%2f2018WR024492&partnerID=40&md5=0c1af0e3dac43a8db5ca473df3202f7a
id 2-s2.0-85075153380
spelling 2-s2.0-85075153380
Kuan W.K.; Xin P.; Jin G.; Robinson C.E.; Gibbes B.; Li L.
Combined Effect of Tides and Varying Inland Groundwater Input on Flow and Salinity Distribution in Unconfined Coastal Aquifers
2019
Water Resources Research
55
11
10.1029/2018WR024492
https://www.scopus.com/inward/record.uri?eid=2-s2.0-85075153380&doi=10.1029%2f2018WR024492&partnerID=40&md5=0c1af0e3dac43a8db5ca473df3202f7a
Tides and seasonally varying inland freshwater input, with different fluctuation periods, are important factors affecting flow and salt transport in coastal unconfined aquifers. These processes affect submarine groundwater discharge (SGD) and associated chemical transport to the sea. While the individual effects of these forcings have previously been studied, here we conducted physical experiments and numerical simulations to evaluate the interactions between varying inland freshwater input and tidal oscillations. Varying inland freshwater input was shown to induce significant water exchange across the aquifer-sea interface as the saltwater wedge shifted landward and seaward over the fluctuation cycle. Tidal oscillations led to seawater circulations through the intertidal zone that also enhanced the density-driven circulation, resulting in a significant increase in the total SGD. The combination of the tide and varying inland freshwater input, however, decreased the SGD components driven by the separate forcings (e.g., tides and density). Tides restricted the landward and seaward movement of the saltwater wedge in response to the varying inland freshwater input in addition to reducing the time delay between the varying freshwater input signal and landward-seaward movement in the saltwater wedge interface. This study revealed the nonlinear interaction between tidal fluctuations and varying inland freshwater input will help to improve our understanding of SGD, seawater intrusion, and chemical transport in coastal unconfined aquifers. ©2019. American Geophysical Union. All Rights Reserved.
Blackwell Publishing Ltd
431397
English
Article

author Kuan W.K.; Xin P.; Jin G.; Robinson C.E.; Gibbes B.; Li L.
spellingShingle Kuan W.K.; Xin P.; Jin G.; Robinson C.E.; Gibbes B.; Li L.
Combined Effect of Tides and Varying Inland Groundwater Input on Flow and Salinity Distribution in Unconfined Coastal Aquifers
author_facet Kuan W.K.; Xin P.; Jin G.; Robinson C.E.; Gibbes B.; Li L.
author_sort Kuan W.K.; Xin P.; Jin G.; Robinson C.E.; Gibbes B.; Li L.
title Combined Effect of Tides and Varying Inland Groundwater Input on Flow and Salinity Distribution in Unconfined Coastal Aquifers
title_short Combined Effect of Tides and Varying Inland Groundwater Input on Flow and Salinity Distribution in Unconfined Coastal Aquifers
title_full Combined Effect of Tides and Varying Inland Groundwater Input on Flow and Salinity Distribution in Unconfined Coastal Aquifers
title_fullStr Combined Effect of Tides and Varying Inland Groundwater Input on Flow and Salinity Distribution in Unconfined Coastal Aquifers
title_full_unstemmed Combined Effect of Tides and Varying Inland Groundwater Input on Flow and Salinity Distribution in Unconfined Coastal Aquifers
title_sort Combined Effect of Tides and Varying Inland Groundwater Input on Flow and Salinity Distribution in Unconfined Coastal Aquifers
publishDate 2019
container_title Water Resources Research
container_volume 55
container_issue 11
doi_str_mv 10.1029/2018WR024492
url https://www.scopus.com/inward/record.uri?eid=2-s2.0-85075153380&doi=10.1029%2f2018WR024492&partnerID=40&md5=0c1af0e3dac43a8db5ca473df3202f7a
description Tides and seasonally varying inland freshwater input, with different fluctuation periods, are important factors affecting flow and salt transport in coastal unconfined aquifers. These processes affect submarine groundwater discharge (SGD) and associated chemical transport to the sea. While the individual effects of these forcings have previously been studied, here we conducted physical experiments and numerical simulations to evaluate the interactions between varying inland freshwater input and tidal oscillations. Varying inland freshwater input was shown to induce significant water exchange across the aquifer-sea interface as the saltwater wedge shifted landward and seaward over the fluctuation cycle. Tidal oscillations led to seawater circulations through the intertidal zone that also enhanced the density-driven circulation, resulting in a significant increase in the total SGD. The combination of the tide and varying inland freshwater input, however, decreased the SGD components driven by the separate forcings (e.g., tides and density). Tides restricted the landward and seaward movement of the saltwater wedge in response to the varying inland freshwater input in addition to reducing the time delay between the varying freshwater input signal and landward-seaward movement in the saltwater wedge interface. This study revealed the nonlinear interaction between tidal fluctuations and varying inland freshwater input will help to improve our understanding of SGD, seawater intrusion, and chemical transport in coastal unconfined aquifers. ©2019. American Geophysical Union. All Rights Reserved.
publisher Blackwell Publishing Ltd
issn 431397
language English
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