干旱区生态环境知识资源中心(Arid): Impact of Hydrostratigraphic Continuity on Brine-to-Freshwater Interface Dynamics: Implications From a Two-Dimensional Parametric Study in an Arid and Endorheic Basin

Arid

DOI	10.1029/2020WR028302
	Impact of Hydrostratigraphic Continuity on Brine-to-Freshwater Interface Dynamics: Implications From a Two-Dimensional Parametric Study in an Arid and Endorheic Basin
	McKnight, S. V.; Boutt, D. F.; Munk, L. A.
通讯作者	McKnight, SV (corresponding author), Univ Massachusetts Amherst, Dept Geosci, Amherst, MA 01003 USA.
来源期刊	WATER RESOURCES RESEARCH
ISSN	0043-1397
EISSN	1944-7973
出版年	2021
卷号	57 期号:4
英文摘要	Despite the prevalence of density-dependent flow systems in the brine-rich aquifers of arid climates and coastal aquifers, the impact of realistic geologic conditions on interface geometry and density-dependent time-sensitive dynamics remains poorly constrained. Salar de Atacama provides an analog for exploring interface dynamics in arid regions. A site-specific two-dimensional hydrostratigraphic interpretation is used to examine the dynamics of the brine-to-freshwater interface. With the same simulation framework and core data, a separate parametric series of hydraulic conductivity distributions with varying horizontal continuity provides a mechanistic explanation for observed dynamics. Comparing modeled interfaces and their sensitivity to perturbations in recharge in each realization yields insight into interface dynamics coupled with horizontal continuity in subsurface heterogeneity. Recharge fluctuation is introduced to each distribution following the interface reaching a dynamic steady state. Metrics for results evaluation include interface slope geometry, interface width, migration length, and response rate. Analyses suggest that the average slope of the modeled interface shallows by 0.01 and 0.05 m . m(-1) for an increase in continuity of highly permeable pathways by a factor of two and three, respectively. Increasing continuity also increases the overall response times and the variability in response. Results indicate that accurate representations of transient dynamics in modeling density-dependent brine-to-freshwater interface dynamics requires the consideration of heterogeneity, as saline intrusion in the highest continuity group extends over twice as far on average and the modeled interface takes over 43% more time on average to reach a new dynamic steady state when compared to their homogeneous counterparts. Plain Language Summary Differences in the density of groundwater from dissolved salt causes groundwater flow to behave differently under different subsurface conditions. This paper focuses on how spatial differences in porosity affects flow behavior and changes the risk of saline groundwater intrusion. Core and groundwater data from the southeastern edge of the salt flat in Salar de Atacama provides information on subsurface physical characteristics and groundwater chemistry. This data is used to create an interpretation of how flow properties vary in time and space. This provides a means for assessing the impact of spatially variable geology on the geometry and the sensitivity of the brine-tofreshwater interface to changes in recharge to an aquifer. We use distributions of the area's geology to test different amounts of geologic variability in the horizontal versus the vertical direction. Results indicate that more horizontal continuity shallows the geometry and increases the time required for a brine-tofreshwater interface to reach a new position following a change in recharge. These model results suggest that it is important to consider how differences in the flow properties of different geologic units impact the response time and the extent of saline intrusion in deserts as well as any other areas that might have salty groundwater.
英文关键词	arid basins density-dependent flow geologic heterogeneity geostatistics groundwater modeling saline intrusion
类型	Article
语种	英语
收录类别	SCI-E
WOS记录号	WOS:000644063800018
WOS关键词	SEA-LEVEL RISE ; COASTAL AQUIFERS ; SEAWATER INTRUSION ; ATACAMA BASIN ; GROUND-WATER ; SALAR ; FLOW ; CLIMATE ; RECHARGE ; FLUXES
WOS类目	Environmental Sciences ; Limnology ; Water Resources
WOS研究方向	Environmental Sciences & Ecology ; Marine & Freshwater Biology ; Water Resources
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/351988
作者单位	[McKnight, S. V.; Boutt, D. F.] Univ Massachusetts Amherst, Dept Geosci, Amherst, MA 01003 USA; [Munk, L. A.] Univ Alaska Anchorage, Dept Geol Sci, Anchorage, AK USA
推荐引用方式 GB/T 7714	McKnight, S. V.,Boutt, D. F.,Munk, L. A.. Impact of Hydrostratigraphic Continuity on Brine-to-Freshwater Interface Dynamics: Implications From a Two-Dimensional Parametric Study in an Arid and Endorheic Basin[J],2021,57(4).
APA	McKnight, S. V.,Boutt, D. F.,&Munk, L. A..(2021).Impact of Hydrostratigraphic Continuity on Brine-to-Freshwater Interface Dynamics: Implications From a Two-Dimensional Parametric Study in an Arid and Endorheic Basin.WATER RESOURCES RESEARCH,57(4).
MLA	McKnight, S. V.,et al."Impact of Hydrostratigraphic Continuity on Brine-to-Freshwater Interface Dynamics: Implications From a Two-Dimensional Parametric Study in an Arid and Endorheic Basin".WATER RESOURCES RESEARCH 57.4(2021).