Laboratory-scale study of mixed barriers in stratified layers with an inclined ocean aquifer boundary

IF 3.5 3区环境科学与生态学 Q2 ENVIRONMENTAL SCIENCES

Journal of contaminant hydrology Pub Date : 2024-09-25 DOI:10.1016/j.jconhyd.2024.104438

Vikas Sharma, Sumedha Chakma

{"title":"Laboratory-scale study of mixed barriers in stratified layers with an inclined ocean aquifer boundary","authors":"Vikas Sharma, Sumedha Chakma","doi":"10.1016/j.jconhyd.2024.104438","DOIUrl":null,"url":null,"abstract":"<div><div>The over-pumping of freshwater makes shoreline aquifers susceptible to seawater intrusion. Most studies on aquifer homogeneity that are used to form management guidelines focus on salinization sensitivity. However, under certain extraction conditions, the geographic structure can be quite diverse, with low-permeability obstacles and preferred flow routes that affect circulation and saline transport mechanisms. Here, we used a laboratory-scale glass box apparatus of dimension 100 × 50 × 10 cm<sup>3</sup> to study intrusion in stratified layers under the influence of an inclined ocean-aquifer boundary with a mixed barrier as a remediation technique. The T<sub>L</sub>\\H ratio ranged from 0.2 to 12.84 for all stratification conditions and remediation installed. There was a 40–48 % decrease in the extent of toe length after installation. With a mixed barrier installed, the height of the intrusion was reduced, resulting in an increase in the T<sub>L</sub>\\H and a decrease in the potential for toe length. The intrusion was delayed by 86.67 % in parallel stratification and 28.22 % in perpendicular stratification after comparing the time frame for base case and the mixed barrier installed condition. A parabolic profile of intrusion was observed in the low-permeability layer, while a convex-outward profile was observed in the higher-permeability layers. Similar results are obtained after conducting the sensitivity analysis. The intrusion follows an increasing pattern of ratio with increasing interaction gap opening in parallel stratification, while for perpendicular stratification, with gap opening from 10 cm to 30 cm, there was a decreasing trend followed by an increasing trend, indicating an increase in magnitude with a similar pattern of intrusion. The results of this investigation shed light on the mixed barrier's suitability for use in realistically diverse coastal aquifers. Future research could explore the utilization of different combinations of new barriers, such as under-surface barriers, which work well for stratified layers, and already established barrier systems, to further improve the efficiency of mixed barriers.</div></div>","PeriodicalId":15530,"journal":{"name":"Journal of contaminant hydrology","volume":"267 ","pages":"Article 104438"},"PeriodicalIF":3.5000,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of contaminant hydrology","FirstCategoryId":"93","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0169772224001426","RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENVIRONMENTAL SCIENCES","Score":null,"Total":0}

引用次数: 0

Abstract

The over-pumping of freshwater makes shoreline aquifers susceptible to seawater intrusion. Most studies on aquifer homogeneity that are used to form management guidelines focus on salinization sensitivity. However, under certain extraction conditions, the geographic structure can be quite diverse, with low-permeability obstacles and preferred flow routes that affect circulation and saline transport mechanisms. Here, we used a laboratory-scale glass box apparatus of dimension 100 × 50 × 10 cm³ to study intrusion in stratified layers under the influence of an inclined ocean-aquifer boundary with a mixed barrier as a remediation technique. The T_L\H ratio ranged from 0.2 to 12.84 for all stratification conditions and remediation installed. There was a 40–48 % decrease in the extent of toe length after installation. With a mixed barrier installed, the height of the intrusion was reduced, resulting in an increase in the T_L\H and a decrease in the potential for toe length. The intrusion was delayed by 86.67 % in parallel stratification and 28.22 % in perpendicular stratification after comparing the time frame for base case and the mixed barrier installed condition. A parabolic profile of intrusion was observed in the low-permeability layer, while a convex-outward profile was observed in the higher-permeability layers. Similar results are obtained after conducting the sensitivity analysis. The intrusion follows an increasing pattern of ratio with increasing interaction gap opening in parallel stratification, while for perpendicular stratification, with gap opening from 10 cm to 30 cm, there was a decreasing trend followed by an increasing trend, indicating an increase in magnitude with a similar pattern of intrusion. The results of this investigation shed light on the mixed barrier's suitability for use in realistically diverse coastal aquifers. Future research could explore the utilization of different combinations of new barriers, such as under-surface barriers, which work well for stratified layers, and already established barrier systems, to further improve the efficiency of mixed barriers.

查看原文本刊更多论文

对具有倾斜海洋含水层边界的分层中的混合障碍物进行实验室规模的研究。

过度抽取淡水使海岸线含水层容易受到海水入侵的影响。大多数用于制定管理准则的含水层均匀性研究都侧重于盐碱化敏感性。然而，在某些开采条件下，含水层的地理结构可能相当多样化，存在低渗透性障碍和优先流动路线，从而影响循环和盐分迁移机制。在此，我们使用实验室规模的玻璃箱仪器（尺寸为 100 × 50 × 10 cm3），研究了在具有混合障碍物的倾斜海洋-含水层边界影响下，作为一种修复技术的分层侵入情况。在所有分层条件下和安装补救措施时，TL\H 比率在 0.2 至 12.84 之间。安装后，趾长范围减少了 40-48%。安装了混合屏障后，入侵高度降低，导致 TL\H 增加，趾长的可能性降低。在平行分层和垂直分层条件下，入侵时间分别延迟了 86.67% 和 28.22%。低渗透率层的入侵呈抛物线型，而高渗透率层的入侵呈凸出型。进行敏感性分析后也得到了类似的结果。在平行分层中，随着相互作用间隙开度的增大，入侵比例呈上升趋势；而在垂直分层中，间隙开度从 10 厘米到 30 厘米，入侵比例呈先下降后上升的趋势，表明入侵量增加，入侵模式相似。这项研究的结果说明，混合隔水层适用于现实中多种多样的沿海含水层。今后的研究可以探索如何将新的隔水层（如对分层效果很好的地表下隔水层）和已建立的隔水层系统进行不同的组合，以进一步提高混合隔水层的效率。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

求助全文

约1分钟内获得全文求助全文

来源期刊

Journal of contaminant hydrology 环境科学-地球科学综合

CiteScore

6.80

自引率

2.80%

发文量

129

审稿时长

68 days

期刊介绍： The Journal of Contaminant Hydrology is an international journal publishing scientific articles pertaining to the contamination of subsurface water resources. Emphasis is placed on investigations of the physical, chemical, and biological processes influencing the behavior and fate of organic and inorganic contaminants in the unsaturated (vadose) and saturated (groundwater) zones, as well as at groundwater-surface water interfaces. The ecological impacts of contaminants transported both from and to aquifers are of interest. Articles on contamination of surface water only, without a link to groundwater, are out of the scope. Broad latitude is allowed in identifying contaminants of interest, and include legacy and emerging pollutants, nutrients, nanoparticles, pathogenic microorganisms (e.g., bacteria, viruses, protozoa), microplastics, and various constituents associated with energy production (e.g., methane, carbon dioxide, hydrogen sulfide). The journal''s scope embraces a wide range of topics including: experimental investigations of contaminant sorption, diffusion, transformation, volatilization and transport in the surface and subsurface; characterization of soil and aquifer properties only as they influence contaminant behavior; development and testing of mathematical models of contaminant behaviour; innovative techniques for restoration of contaminated sites; development of new tools or techniques for monitoring the extent of soil and groundwater contamination; transformation of contaminants in the hyporheic zone; effects of contaminants traversing the hyporheic zone on surface water and groundwater ecosystems; subsurface carbon sequestration and/or turnover; and migration of fluids associated with energy production into groundwater.