气候变化领域集成服务门户(CCPortal): Saltwater Intrusion Into a Confined Island Aquifer Driven by Erosion, Changing Recharge, Sea-Level Rise, and Coastal Flooding

CCPortal

DOI	10.1029/2023WR036394
	Saltwater Intrusion Into a Confined Island Aquifer Driven by Erosion, Changing Recharge, Sea-Level Rise, and Coastal Flooding
	Stanic, S.; LeRoux, N. K.; Paldor, A.; Mohammed, A. A.; Michael, H. A.; Kurylyk, B. L.
发表日期	2024
ISSN	0043-1397
EISSN	1944-7973
起始页码	60
结束页码	1
卷号	60 期号:1
英文摘要	Aquifers on small islands are at risk of salinization due to low elevations and limited adaptive capacity, and present risks will be exacerbated by climate change. Most studies addressing small-island saltwater intrusion (SWI) have focused on homogeneous sandy islands and one or two hydraulic disturbances. We herein investigate SWI dynamics in a layered, confined island aquifer in response to multiple environmental perturbations related to climate change, with two considered in tandem. Our field and modeling work is based on an island aquifer that provides the drinking water supply for an Indigenous community in Atlantic Canada. Observation well data and electrical resistivity profiles were used to calibrate a numerical model (HydroGeoSphere) of coupled groundwater flow and salt transport. The calibrated model was used to simulate the impacts of climate change including sea-level rise (SLR), storm surge overtopping, changing aquifer recharge, and erosion. Simulated aquifer conditions were resilient to surges because the confining layer prevented deeper saltwater leaching. However, reduced recharge and erosion resulted in saltwater wedge migration of 170 and 110 m, respectively when considered individually, and up to 295 m (i.e., into the wellfield) when considered together. Despite the confining conditions, SLR resulted in wedge migration up to 55 m as the confining pressures were not sufficient to resist wedge movement. This is the first study to harness an integrated, surface-subsurface hydrologic model to assess effects of coastal erosion and other hydroclimatic stressors on island aquifers, highlighting that climate change can drive extensive salinization of critical groundwater resources. Due to their limited resources and adaptive capacity, small islands are highly vulnerable to climate change impacts, including saltwater intrusion. Freshwater needs on small islands are often sourced from small aquifers that are in delicate balance between conditions in the ocean, atmosphere, and land. In this study, we investigate the movement of saltwater into the freshwater aquifer of a small island that provides drinking water resources for an Indigenous First Nation. We consider climatic changes in the ocean (sea-level rise (SLR), storm surges, and related coastal erosion) and atmosphere (changes to net precipitation) and associated impacts to the island's fresh groundwater resources. We use field data paired with a mathematical model and demonstrate that the pressurized conditions of the layered island aquifer make it more resilient to SLR than unconfined aquifers in sandy islands are. However, the aquifer's freshwater volume is susceptible to coastal erosion and reduced precipitation, particularly when these happen at the same time. Results point to coastal erosion as a potential widespread driver of freshwater loss along eroding portions of the global coastline. A surface-subsurface numerical model is used to investigate climate change impacts on island groundwater resources used for water supplyThe confined aquifer is resilient to storm surges which only salinize the unpumped surficial aquifer before being flushedCoastal erosion and recharge reductions result in the most saltwater intrusion and can work in tandem to threaten future water supply
英文关键词	saltwater intrusion; layered aquifer; coastal flooding; morphodynamics; climate change
语种	英语
WOS研究方向	Environmental Sciences & Ecology ; Marine & Freshwater Biology ; Water Resources
WOS类目	Environmental Sciences ; Limnology ; Water Resources
WOS记录号	WOS:001142101900001
来源期刊	WATER RESOURCES RESEARCH
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/307581
作者单位	Dalhousie University; Dalhousie University; University of Delaware; Syracuse University; Syracuse University; University of Delaware
推荐引用方式 GB/T 7714	Stanic, S.,LeRoux, N. K.,Paldor, A.,et al. Saltwater Intrusion Into a Confined Island Aquifer Driven by Erosion, Changing Recharge, Sea-Level Rise, and Coastal Flooding[J],2024,60(1).
APA	Stanic, S.,LeRoux, N. K.,Paldor, A.,Mohammed, A. A.,Michael, H. A.,&Kurylyk, B. L..(2024).Saltwater Intrusion Into a Confined Island Aquifer Driven by Erosion, Changing Recharge, Sea-Level Rise, and Coastal Flooding.WATER RESOURCES RESEARCH,60(1).
MLA	Stanic, S.,et al."Saltwater Intrusion Into a Confined Island Aquifer Driven by Erosion, Changing Recharge, Sea-Level Rise, and Coastal Flooding".WATER RESOURCES RESEARCH 60.1(2024).