Controls on coastal saline groundwater across North America
Groundwater is crucial to sustaining coastal freshwater needs. About 32 million people in the coastal USA rely on groundwater as their primary water source. With rapidly growing coastal communities and increasing demands for fresh groundwater, understanding controls of continental-scale coastal grou...
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| Language: | English |
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IOP Publishing
2025-01-01
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| Series: | Environmental Research Letters |
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| Online Access: | https://doi.org/10.1088/1748-9326/ada973 |
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| author | Daniel V Kretschmer Holly A Michael Nils Moosdorf Gualbert H P Oude Essink Marc F P Bierkens Thorsten Wagener Robert Reinecke |
| author_facet | Daniel V Kretschmer Holly A Michael Nils Moosdorf Gualbert H P Oude Essink Marc F P Bierkens Thorsten Wagener Robert Reinecke |
| author_sort | Daniel V Kretschmer |
| collection | DOAJ |
| description | Groundwater is crucial to sustaining coastal freshwater needs. About 32 million people in the coastal USA rely on groundwater as their primary water source. With rapidly growing coastal communities and increasing demands for fresh groundwater, understanding controls of continental-scale coastal groundwater salinity is critical. To investigate what hydrogeological factors (e.g. topography, hydraulic conductivity) control coastal saline groundwater at continental scales, we have simulated variable-density groundwater flow across North America with the newly developed Global Gradient-based Groundwater Model with variable Densities (G ^3 M-D). The simulation results suggest that under a steady climate and pre-development conditions (i.e. steady 30-year mean groundwater recharge, no withdrawals nor sea level rise) saline groundwater is present in 18.6% of North America’s coastal zone, defined as up to 100 km inland and up to 100 m above mean sea level. We find that the coastal zone is particularly vulnerable to containing saline groundwater at low hydraulic gradients (<10 ^−4 ) and large hydraulic conductivities (>10 ^−2 m d ^−1 ). To analyze model parameter sensitivities, i.e. which parameters control the resulting distribution of saline groundwater, we utilize the inherent spatial model variability. We find that hydraulic gradient, topographic gradient, hydraulic conductivity, and aquifer depth are important controls in different places. However, no factor controls coastal groundwater salinization alone, suggesting that parameter interactions are important. Using G ^3 M-D based on G ^3 M, a model that previous work found to be strongly controlled by topography, we find no controlling influence of recharge variability on the saline groundwater distribution in North America. Despite a likely overestimation of saline interface movement, the model required 492 000 years to reach a near-steady state, indicating that the saline groundwater distribution in North America has likely been evolving since before the end of the last ice age, approximately 20 000 years ago. |
| format | Article |
| id | doaj-art-8d233ee34db644aaa7aae8bbf923b5f5 |
| institution | Kabale University |
| issn | 1748-9326 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
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| series | Environmental Research Letters |
| spelling | doaj-art-8d233ee34db644aaa7aae8bbf923b5f52025-02-07T15:22:41ZengIOP PublishingEnvironmental Research Letters1748-93262025-01-0120202406510.1088/1748-9326/ada973Controls on coastal saline groundwater across North AmericaDaniel V Kretschmer0https://orcid.org/0000-0003-0115-1268Holly A Michael1https://orcid.org/0000-0003-1107-7698Nils Moosdorf2https://orcid.org/0000-0003-2822-8261Gualbert H P Oude Essink3https://orcid.org/0000-0003-0931-6944Marc F P Bierkens4https://orcid.org/0000-0002-7411-6562Thorsten Wagener5https://orcid.org/0000-0003-3881-5849Robert Reinecke6https://orcid.org/0000-0001-5699-8584Institute of Geography, Johannes Gutenberg-University Mainz , Mainz, Germany; Institute of Environmental Science and Geography, University of Potsdam , Potsdam, GermanyDepartment of Earth Sciences, University of Delaware , Newark, DE, United States of AmericaLeibniz Centre for Tropical Marine Research (ZMT) , Bremen, Germany; Institute of Geosciences, University of Kiel , Kiel, GermanyUnit Subsurface and Groundwater Systems , Deltares, Utrecht, The Netherlands; Department of Physical Geography, Utrecht University , Utrecht, The NetherlandsUnit Subsurface and Groundwater Systems , Deltares, Utrecht, The Netherlands; Department of Physical Geography, Utrecht University , Utrecht, The NetherlandsInstitute of Environmental Science and Geography, University of Potsdam , Potsdam, GermanyInstitute of Geography, Johannes Gutenberg-University Mainz , Mainz, Germany; Institute of Environmental Science and Geography, University of Potsdam , Potsdam, GermanyGroundwater is crucial to sustaining coastal freshwater needs. About 32 million people in the coastal USA rely on groundwater as their primary water source. With rapidly growing coastal communities and increasing demands for fresh groundwater, understanding controls of continental-scale coastal groundwater salinity is critical. To investigate what hydrogeological factors (e.g. topography, hydraulic conductivity) control coastal saline groundwater at continental scales, we have simulated variable-density groundwater flow across North America with the newly developed Global Gradient-based Groundwater Model with variable Densities (G ^3 M-D). The simulation results suggest that under a steady climate and pre-development conditions (i.e. steady 30-year mean groundwater recharge, no withdrawals nor sea level rise) saline groundwater is present in 18.6% of North America’s coastal zone, defined as up to 100 km inland and up to 100 m above mean sea level. We find that the coastal zone is particularly vulnerable to containing saline groundwater at low hydraulic gradients (<10 ^−4 ) and large hydraulic conductivities (>10 ^−2 m d ^−1 ). To analyze model parameter sensitivities, i.e. which parameters control the resulting distribution of saline groundwater, we utilize the inherent spatial model variability. We find that hydraulic gradient, topographic gradient, hydraulic conductivity, and aquifer depth are important controls in different places. However, no factor controls coastal groundwater salinization alone, suggesting that parameter interactions are important. Using G ^3 M-D based on G ^3 M, a model that previous work found to be strongly controlled by topography, we find no controlling influence of recharge variability on the saline groundwater distribution in North America. Despite a likely overestimation of saline interface movement, the model required 492 000 years to reach a near-steady state, indicating that the saline groundwater distribution in North America has likely been evolving since before the end of the last ice age, approximately 20 000 years ago.https://doi.org/10.1088/1748-9326/ada973groundwater salinitycontinental groundwater modelvariable densitiesgroundwater modelcoastal zone |
| spellingShingle | Daniel V Kretschmer Holly A Michael Nils Moosdorf Gualbert H P Oude Essink Marc F P Bierkens Thorsten Wagener Robert Reinecke Controls on coastal saline groundwater across North America Environmental Research Letters groundwater salinity continental groundwater model variable densities groundwater model coastal zone |
| title | Controls on coastal saline groundwater across North America |
| title_full | Controls on coastal saline groundwater across North America |
| title_fullStr | Controls on coastal saline groundwater across North America |
| title_full_unstemmed | Controls on coastal saline groundwater across North America |
| title_short | Controls on coastal saline groundwater across North America |
| title_sort | controls on coastal saline groundwater across north america |
| topic | groundwater salinity continental groundwater model variable densities groundwater model coastal zone |
| url | https://doi.org/10.1088/1748-9326/ada973 |
| work_keys_str_mv | AT danielvkretschmer controlsoncoastalsalinegroundwateracrossnorthamerica AT hollyamichael controlsoncoastalsalinegroundwateracrossnorthamerica AT nilsmoosdorf controlsoncoastalsalinegroundwateracrossnorthamerica AT gualberthpoudeessink controlsoncoastalsalinegroundwateracrossnorthamerica AT marcfpbierkens controlsoncoastalsalinegroundwateracrossnorthamerica AT thorstenwagener controlsoncoastalsalinegroundwateracrossnorthamerica AT robertreinecke controlsoncoastalsalinegroundwateracrossnorthamerica |