Seawater Intrusion Research Articles

Climate change has emerged as a significant threat to global development, disproportionately affecting vulnerable populations, particularly in developing countries like Bangladesh. This paper explores the complex relationships between climate change and vulnerability, highlighting how geographical exposure, socioeconomic conditions, and gender disparities increase the susceptibility to climate-induced hazards such as floods, cyclones, and salinity intrusion. Vulnerability is not steadfast in the environmental factors, but it is deeply influenced by poverty, limited access to resources, and systematic inequalities. Discussion emphasizes the gender nature of vulnerability, with women facing additional barriers to adaptation due to traditional roles and social constraints. Institutional policy responses are viewed, underscoring the need for inclusive governance, education, and long-term financial support. The study recommends a holistic and equity-focused approach to climate adaptation that prioritizes empowerment, gender inclusion, and localized solutions. Strengthening institutional capacity, increasing climate finance, and integrating climate into education and policy frameworks are vital to sustainable adaptation.

The hydrosystem composed of Lake Togo, Lagoon of Togoville, and Lagoon of Aného is located in the coastal zone of Togo and receives important and different kinds of mining waste that cause its degradation. This study aims to evaluate the physicochemical and metallic quality of these waters and determine the possible sources of these contaminants using geostatistical, multivariate, and special analysis methods. These waters were very mineralized according to the average conductivity (15.51 mS/cm). Average contents (μg/L) in trace elements varied from 2.46 μg/L for As to 141.63 μg/L for Pb. Average levels of Cd, Pb, Cr, and Ni were significantly higher than the WHO standards. Trace elements and physicochemical parameters showed strong spatial variations with the highest values recorded downstream of the hydrosystem. The main possible source of trace element pollution was the intrusion of seawater loaded with phosphate effluent, followed by atmospheric deposition and soil leaching. This hydrosystem, therefore, deserves special attention for better planning its management.

Durian is one of the most economically important fruit crops in Vietnam, yet its productivity was severely impacted by the 2020 drought caused by saltwater intrusion in the Mekong Delta. This extreme event underscored the urgent need to understand factors influencing both drought resilience and crop yield. Limited research exists on how farm-level practices interact with environmental stressors in durian cultivation, creating a gap in evidence-based adaptation strategies. To address this, a cross-sectional study was conducted in 2022–2023 across 60 durian farms in the Mekong Delta, Vietnam. The study aimed to identify key agronomic and environmental factors affecting durian mortality during the 2020 drought and yield performance during the recovery period. Multiple linear regression and non-linear regression models were employed to identify the predictors of durian mortality during the drought and subsequent yield performance. The regression model revealed a strong correlation between durian mortality rate and its predictors (R² = 0.827). Results indicated that for every 1% increase in the proportion of the Monthong variety, durian mortality under drought conditions increased by 0.36% (95% CI: 0.22–0.49). Furthermore, durian yield following the drought was found to be negatively correlated with irrigation volume. These findings lay the foundation for developing drought coping strategies in durian orchards, highlighting the need for further research on optimising variety selection, irrigation practices, and fertilisation management

Soil salinization, driven by seawater intrusion, significantly challenges agricultural productivity in coastal regions. Horticultural crops, such as shallots, are especially sensitive to salinity stress, which impairs growth, nutrient uptake, and bulb yield. This study explored halotolerant plant growth-promoting bacteria from saline soils in East Nusa Tenggara, Indonesia, to reduce salinity stress in shallots. Seventeen bacterial isolates were screened for halotolerance, and eight of them were capable of growing at 1,250 mM NaCl (OD600 ≥ 0.5). Selected halotolerant isolates also exhibited the ability to produce indole-3-acetic acid (IAA) and exopolysaccharides (EPS), solubilize P, K, and Zn, produce siderophores, and exhibit 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity with varying tolerance at salinity levels up to 1,000 mM NaCl. Inoculation with these isolates significantly improved shallot seedling growth under 90 to 230 mM NaCl, with <em>Enterobacter hormaechei</em> demonstrating the best performance. Bacterial inoculation elevated 47 to 64% proline and 15 to 107% NO<sub>3</sub><sup>−</sup> levels in shallot leaves compared to uninoculated plants, contributing to osmotic adjustment and enhanced nutrient assimilation under salt stress in laboratory trials. Single-strain (<em>E. hormaechei</em>) and a consortium of compatible strains (<em>E. hormaechei </em>strain R11 and M119.1, <em>Klebsiella pneumoniae</em> strain A95, <em>K. variicola</em> strain R198, and <em>Pseudochrobactrum asaccharolyticum </em>strain C167.1) inoculation significantly increased shoot dry weight (100% and 69% each) compared to uninoculated plants under salt stress. These findings advance the current understanding of microbial-assisted salinity mitigation and support broader strategies for climate-resilient, sustainable agriculture in saline-prone coastal regions.

Aims: Focusing on local communities in Con Ho Islet, Tra Vinh Province, this paper demonstrates the transformation in the livelihoods of the local people from traditional agriculture to ecotourism in response to environmental and economic changes, within the context of Vietnam’s commitment to Sustainable Development Goals (SDGs). Method: To be more specific, qualitative methods were conducted with the combination of semi-structured interviews with five local households and participant observations throughout field trips in 2024 and 2025 regarding three visits for ten days. The main frameworks in this paper are Cultural Ecology and Rational Choice Theory. Those frameworks support the reason why the locals choose the adaptive decisions based on climate change pressure and cultural traditions. Results: In our findings, we found that the way response of local communities to ecological stressors such as coastal erosion and salinity intrusion is culturally rational and informed. Conclusions: These local reactions align with some of the SDGs, especially Goals 1, 8, 13, and 14, which could expose the contribution of the locals to the nation and global sustainability target through their adaption to the change of environment.

Advancing Aquifer Monitoring: TDEM’s Application in Seawater Intrusion Detection within Heterogeneous Coastal Aquifers of the Nile Delta

Abstract:- This research paper examines the growing threats posed by climate change to atolls—ring-shaped coral islands found predominantly in tropical ocean regions. These islands, characterized by low elevation and fragile ecosystems, are among the most vulnerable geographical features on Earth in the face of climate change. The study explores how rising sea levels, increasing ocean temperatures, coral bleaching, saltwater intrusion into freshwater sources, and more frequent extreme weather events are disrupting both the natural environment and human settlements on atolls. “These environmental stressors not only degrade coral reefs and coastal landscapes but also threaten the livelihoods, water and food security, and habitability of local Communities.”1 “Focusing on case studies from the Maldives, Kiribati, and the Marshall Islands, this paper highlights how atoll nations are experiencing the front-line impacts of climate change.”2 It also reviews the adaptation strategies being employed, including coastal defence structures, coral restoration efforts, rainwater harvesting systems, and international advocacy for climate justice. The paper concludes that unless global carbon emissions are significantly reduced and adequate technical and financial support is extended to these vulnerable island states, many atolls could become uninhabitable within this century. The displacement of populations due to environmental degradation may lead to the emergence of climate refugees, creating new humanitarian and geopolitical challenges. Thus, this research not only raises environmental concerns but also calls for a shared global responsibility, particularly from high-emission industrialized nations, to support atoll regions through coordinated climate action and international cooperation.

This study investigates the determinants of household-level adaptation strategies to climate variability and saltwater intrusion in the coastal regions of Central Vietnam. Using a Multinomial Logistic Regression (MNL) model, the analysis is based on a cross-sectional survey of 356 farming households, focusing on four primary adaptation measures: vegetable production, shrimp farming, adoption of salt-tolerant rice varieties, and the lotus-fish farming model. The results reveal that socio-economic, demographic, environmental, and institutional factors significantly influence the adoption of specific adaptation strategies. Key determinants include gender, education, age, farming experience, household income, land characteristics, access to information, credit services, membership in civic organizations, and participation in training programs. Male-headed households and those with greater access to climate information and social networks were more likely to adopt diverse and complex adaptation strategies. In contrast, households with limited land resources, lower incomes, or lacking institutional support were less adaptive. The findings highlight the heterogeneity of adaptive behaviors and the need for tailored interventions. From a policy perspective, enhancing institutional capacity-especially through targeted training, increased access to subsidized credit, and support for community-based organizations-can significantly strengthen farmers' adaptive capacities. Moreover, the study contributes to filling key research gaps in the Southeast Asian context by integrating socio-economic and environmental variables into a unified analytical framework. These insights are critical for designing inclusive and effective climate adaptation policies aimed at safeguarding rural livelihoods and promoting sustainable agricultural development in climate-vulnerable regions.

Land subsidence significantly threatens vulnerable coastal environments. This study aims to explore how Semarang’s government, local communities, and researchers address land subsidence and its role in exacerbating flood risk, against the backdrop of ongoing efforts within flood risk governance. Employing an integrated mixed-methods approach, the research combined quantitative geospatial analysis (InSAR and land cover change detection) with qualitative socio-political and governance analysis (interviews, FGDs, field observations). Findings show high subsidence rates in Semarang. Line of sight displacement measurements revealed a continuous downward trend from late 2014 to mid-2023, with rates varying from −8.8 to −10.1 cm/year in Karangroto and Sembungharjo. Built-up areas concurrently expanded from 21,512 hectares in 2017 to 23,755 hectares in 2023, largely displacing cropland and tree cover. Groundwater extraction was identified as the dominant driver, alongside urbanization and geological factors. A critical disconnect emerged: community views focused on flooding, often overlooking subsidence’s fundamental role as an exacerbating factor. The study concluded that multi-level collaboration, improved risk communication, and sustainable land management are critical for enhancing urban coastal resilience against dual threats of subsidence and flooding. These insights offer guidance for similar rapidly developing coastal cities.

In Mexico, there has been a great growth in deep wells that extract groundwater at unsustainable levels. It is necessary to document the background and analyze the elements that historically converged for the appearance of failures to control extractions. The objective is to identify historical deviations in the application of current regulations according to the administrative and operational capacity of the water authority that led to the overexploitation of aquifers. The study method is reflective-analytical of a qualitative nature supported based on official data and documentary sources. A weak water authority, with budgetary and technical limitations, and poorly focused policies or programs, led to a lack of control of extractions, coupled with legislation and its limited, although often well-intentioned, regulatory legal framework, which resulted in the absence or poor application of regulatory instruments for transparent and efficient compliance.

Seawater intrusion (SWI) in coastal aquifers in arid areas is a global threat to the groundwater quality. This study aimed to assess SWI in the Sudr coastal aquifer in South Sinai, Egypt, by integration of hydrochemical, isotopic, remote sensing (RS) and machine learning (ML) approaches. The developed ML technique is based on the random vector functional link (RVFL) using the Tactical unit algorithm (TAU) to predict the value of the parameters of the RVFL, which leads to an enhancement in the prediction of seawater intrusion indicators. The hydrogeochemical data of the groundwater wells in the two periods (1996 and 2022) were used as inputs for the ML method. The groundwater chemistry in the study area was in the following order: Na > Ca > Mg > K and Cl > SO4 > HCO3. Ionic ratios highlighted groundwater–seawater mixing and reverse ion exchange processes. Based on the Cl−/Br− ratio and O18& D data, seawater intrusion is the primary source of groundwater salinization. The results show that 83.33% of groundwater has a seawater mixing index (SMI) > 1, indicating that mixing with seawater has a significant impact on groundwater chemistry. Also, the Hydrochemical Facies Evolution Diagram (HFE-D) revealed that 83.33% of the area is affected by SWI. According to monitoring years (1996–2022), vegetation cover represented by the NDVI has increased by 1522.21 ha in the region, consequently, groundwater extraction increased. Groundwater salinity accelerated to 30.41% and 5.59% for highly saline and very saline during this period. The results of the ML technique were compatible with the previous analysis, and we compared the RVFL results based on TAU with other state-of-the-art methods using different performance metrics. The outcomes demonstrated a high applicability of RVFL to enhance the model prediction. Additionally, the applied ML model could effectively predict the seawater intrusion indicators in coastal aquifers such as Cl/HCO3, Cl/Br, TDS and Cl. Therefore, these findings can help policy makers and stakeholders manage water resources sustainably in coastal aquifers.

This research examines the potential for sustainable tourism development in Rogbeh Village, a socio-economically marginalized settlement situated along the ecologically fragile Shadegan Lagoon in southwestern Iran. Confronting intersecting challenges of environmental degradation (e.g., pollution, habitat loss) and socio-economic vulnerability (e.g., youth outmigration, infrastructure deficits), this study proposes a participatory tourism framework that synergistically integrates Indigenous cultural heritage—including Arabic-speaking Bahrani traditions, vernacular stilt architecture, and artisanal houri canoe craftsmanship—with regenerative infrastructure design. Employing a robust mixed methodology, the research synthesizes: comprehensive SWOT analysis to identify strengths (e.g., lagoon-centric livelihoods, biodiversity hotspots), weaknesses (e.g., absent wastewater treatment, limited tourist accommodations), opportunities(e.g., Ramsar Convention recognition), and threats (e.g., saltwater intrusion); semi-structured interviews with 45 key stakeholders (30 villagers, 10 local officials, 5 NGO representatives), revealing community priorities and ecological concerns; quantitative datasets on water quality, demographic trends, and livelihood dependency ratios. Findings demonstrate Rogbeh’s unique cultural-ecological landscape as a high-potential ecotourism destination. However, critical barriers—notably institutional fragmentation, sanitation deficiencies, and seasonal eco-nomic instability require systematic intervention. The study advocates a three-pillar solution: eco-sensitive infrastructure: reed-built lodges using solar energy, grey-water recycling, and elevated walkways to minimize wetland disruption; community led governance: tourism coopera-tives allocating 30% of revenues to local healthcare/education, with microgrants for women-led enterprises; this model positions Rogbeh as a replicable prototype where cultural resilience, ecological stewardship, and equitable benefit-shar-ing catalyze holistic sustainability in marginalized wetland communities offering transformative insights for global South contexts facing similar climate-poverty nexuses.

The increase in population and economic activities at Federal Polytechnic Damaturu has resulted in significant strain on the existing water resources within the institution and surrounding areas. To address the water demand for domestic and other associated activities in the institution and its vicinity, this study was conducted to evaluate the groundwater potential in the area. The aquifer parameters in the study area were examined using the electrical resistivity technique. Two aquifer zones were identified in the study area. The first aquifer was shallow and semi-confined, while the second aquifer was confined and found at a considerable depth. The thickness of the aquifer ranged from 46 to 90 meters. The hydraulic conductivity of the aquifer was between 1. 7 and 4. 2 meters per day, with an average of 2. 7 meters per day. The transmissivity of the aquifer in the study area varied from 87 to 241 square meters per day, with a mean of 160 square meters per day. The porosity of the aquifer was between 27. 9 and 32%, yielding an average of 29. 7%. The values of the aquifer parameters in the study area are moderately elevated, indicating that the area possesses good groundwater potential. According to the findings of this research, groundwater extraction in the study area should focus on the second aquifer for high-quality and sustainable water supply. A comparison of the outcomes of this study with the work of previous researchers in Damaturu, revealed that the depth to the second aquifer in Damaturu varied across the region due to site-specific differences in deposition within the Chad Basin. The southeastern section of the study area shows considerable potential for groundwater extraction and it is recommended for borehole location.

The coastal zone presents complex hydrodynamic interactions among inland groundwater, reservoir water, and intruding seawater, with important implications for ecosystem functioning and water quality. However, the relative roles of hydraulic connectivity and seawater-driven salinity gradients in shaping microbial communities at the aquifer-reservoir interface remain unclear. Here, we integrated hydrochemical analyses with high-throughput 16S rRNA gene sequencing to investigate bacterial community composition, assembly processes, and co-occurrence network patterns across groundwater_in (entering the reservoir), groundwater_out (exiting the reservoir), and reservoir water in a coastal system. Our findings reveal that seawater intrusion exerts a stronger influence on groundwater_out, leading to distinct chemical profiles and salinity-driven environmental filtering, whereas hydraulic connectivity promotes greater microbial similarity between groundwater_in and reservoir water. Groundwater samples exhibited higher alpha and beta diversity compared to the reservoir, with dominant taxa such as Comamonadaceae, Flavobacteriaceae, and Rhodobacteraceae serving as indicators of seawater intrusion. Community assembly analyses showed that homogeneous selection predominated, especially under strong salinity gradients, while dispersal limitation and spatial distance also contributed in areas of reduced connectivity. Key chemical factors, including TDS, Na+, Cl-, Mg2+, and K+, strongly shaped groundwater communities. Additionally, groundwater bacterial networks were more complex and robust than those in reservoir water, suggesting enhanced resilience to salinity stress. Collectively, this study demonstrates that salinity gradients can override the effects of hydraulic connectivity in structuring bacterial communities and their networks at coastal interfaces. Our findings provide novel microbial insights relevant for understanding biogeochemical processes and support the use of microbial indicators for more sensitive monitoring and management of coastal groundwater resources.

Adopting climate-smart agriculture in the coastal area of Bangladesh faces challenges, as well as farmers' vulnerability to frequent natural disasters and salinity intrusion. The main aims of this study were to assess the extent of CSA technologies adopted by the farmers and to explore the contributions of the selected characteristics of the coastal farmers to the adoption of CSA. An interview schedule was used to collect data from 354 coastal farmers of three districts, namely Satkhira, Khulna, and Bagerhat, through a ‘Multistage random sampling method’ in 2022. Both inferential and descriptive statistics were used. A complete model multiple regression analysis was used to investigate how the predictor variables affected the outcome variables. Results indicate that about 57.91% of the coastal farmers had medium adoption, followed by 22.88% high and 19.21% poor adoption of CSA. Out of the 19 identified CSA technologies, “the use of thread pipe/plastic pipe for irrigation” ranked first and indicated the highest extent of adoption by the coastal farmers. Farmers’ annual agricultural income, extension contact, training exposure, knowledge of CSA, and attitude towards CSA significantly positively contributes to their adoption of CSA. Extension services, community-based training, and awareness campaigns can play a vital role in escalating farmers' adoption of CSA. Therefore, addressing climate change and building climate resilience in agriculture requires practical support to enable farmers to adopt and sustain CSA. Int. J. Agril. Res. Innov. Tech. 15(1): 39-47, June 2025

Given the lack of rainfall during the dry season in Greece and other countries, groundwater is important in meeting water needs for all uses. Reliable simulation of groundwater flow and predictions of groundwater levels under different management scenarios, in light of water crisis, are essential tools for the sustainable management of aquifers. In this paper, the MODFLOW code for simulating groundwater flow was applied to the Greek section of the transboundary Serres river basin in a complex aquifer system developed in alluvial deposits. The groundwater of the basin is critical for the fulfillment of both the irrigation requirements of an extensive local agricultural activity and the domestic needs of a significant population. Data necessary for model construction and simulation was provided by the relevant authorities and literature. The model calibration is considered successful as the simulated values show a statistically acceptable fit to the measured data. Sensitivity analysis shows that the aquifer’s storage coefficient change has the greatest impact on the groundwater level. In a management scenario where groundwater extraction is reduced by 5% over a ten-year period, the groundwater level is projected to rise by approximately 0.17 m. In contrast, in the worst-case scenario, where groundwater extraction increases by 6.5% reaching at a critical point regarding the sustainability of the groundwater resources in the area, the average groundwater level is expected to drop by 0.72 m, resulting in the reduction of aquifer reserves. The model serves as a valuable tool for mitigating and adapting to the impacts of the climate crisis, as well as for formulating policies that promote the sustainable management and rational use of the aquifer.

Problem definition: Most of the world’s population relies on coastal aquifers for freshwater supplies. Groundwater is experiencing substantial overdrafts and facing ever-mounting freshwater demand. Existing groundwater management strategies are myopic and fail to coordinate production and the operation of protection approaches, including seawater intrusion barriers (SWIBs) and managed aquifer recharge (MAR). Motivated by the urgency of sustainable groundwater management, we investigate how to optimize the joint operations of groundwater production, protection (by injecting fresh water through SWIBs), and replenishment (via MAR). Methodology/results: We model a central planner’s decision on groundwater production, freshwater injection quantities, and artificial replenishment using stochastic dynamic models and identify that the optimal groundwater management policies follow a threshold-type structure. We find that SWIBs and MAR are strategic complements, except in cases with very high groundwater levels, when they turn into strategic substitutes. When the penalty for low groundwater levels decreases, the planner should use SWIBs more aggressively if groundwater levels are low and more conservatively if they are high. A similar pattern holds when natural recharge becomes more abundant, assuming that the natural recharge quantity has no impact on the purchasing cost of imported water. Moreover, we calibrate our model using real data sets in Orange County, California and find that the joint operations of SWIBs and MAR expand groundwater operational flexibility. In contrast, employing SWIBs alone comes at the expense of a lower groundwater level. Managerial implications: Our analysis offers strategic guidance on when to use SWIBs and MAR as complements or substitutes based on groundwater levels. It highlights the value of their joint operation in stabilizing groundwater, especially amid worsening droughts. Funding: This work was partially supported by the National Natural Science Foundation of China [Grants 72242106, 72242107, and 72188101]. Supplemental Material: The online appendix is available at https://doi.org/10.1287/msom.2022.0441 .

Salt contamination of water supplies in tidal rivers is a global problem, but it has received little attention beyond site-specific studies. Drought, sea-level rise, navigation channel dredging, and watershed land-use change increase the risk of salinization and threaten drinking water supplies, agricultural irrigation, and infrastructure (via corrosion). The emerging issue of salt contamination of water supplies in tidal rivers and its diverse impacts highlight the critical need for interdisciplinary research that must integrate knowledge from oceanography, hydrology, and water resource management. Here we elucidate oceanic and hydrological processes regulating saltwater intrusion into estuaries and tidal rivers as well as watershed processes driving enhanced chemical weathering and export of watershed salts into rivers. By synthesizing studies around the world, we discuss how sea-level rise, prolonged drought, and increasingly extreme weather events in a changing climate are driving more frequent saltwater intrusion events that threaten water security globally. We propose a convergent research agenda toward the development of a decision support tool for salinity management. Specifically we recommend making ion-specific measurements and developing hydrological-hydrodynamic models to simulate the transport of major salt ions. These models can then be combined with artificial intelligence algorithms and enhanced monitoring to explore management strategies with stakeholders.

This study investigates the salinization processes affecting the coastal aquifer within the Torre Guaceto State Nature Reserve, a Mediterranean coastal area characterized by a unique ecological value of a brackish wetland threatened by water-intensive agricultural activities. Groundwater salinization threatens biodiversity, agriculture, and water resource sustainability. This work integrates hydrogeological monitoring, geochemical and isotopic analyses, and geophysical surveys to understand salinity dynamics and identify key drivers, such as seawater intrusion, irrigation practices, and climate change. Data collected during monitoring campaigns from 2022 to 2024 reveal significant seasonal and spatial variations in groundwater salinity influenced by natural and human-induced factors. The results indicate that salt recycling from irrigation and marine spray deposition are important local contributors to groundwater salinity, in addition to seawater intrusion. These findings highlight the urgent need for integrated groundwater management approaches considering the combined effects of agricultural practices, irrigation water quality, and climate variability tailored to Mediterranean coastal ecosystems.

Seawater intrusion threatens groundwater resources in coastal regions, including southern Baldwin County, Alabama, where the freshwater-saltwater interface dynamics remain poorly understood. To address this gap, this study uses combined physics-based and machine-learning models to quantify seawater intrusion caused by natural (storm surges) and anthropogenic (human activities) perturbations. The long short-term memory network and wavelet analysis were used to assess vertical aquifer vulnerabilities, revealing that the shallow part of the Coastal lowlands aquifer system (CL1) in the southern Baldwin County region is more susceptible to sea level rise and groundwater extraction than deeper aquifers. Based on these findings, a cross-sectional numerical model (physics approach) for the CL1 aquifer was developed to evaluate tidal and storm surge effects, using Tropical Storm Claudette (June 2021) as a case study. Results showed that tidal fluctuations had a minimal impact on the saltwater-freshwater interface location, whereas storm surges caused substantial inland movement, with effects lasting for nine months. The steady-state version of the three-dimensional (3D) physical model predicted seawater intrusion across the entire area, and convolutional neural network-based modeling further validated the model results. The 3D physical model was also applied to a smaller area to assess human impact on the saltwater interface due to two groundwater pumping scenarios (± 50% of the baseline pumping rate). Results revealed that a 50% increase in groundwater withdrawals caused seawater to advance ~ 320 m inland, whereas a 50% reduction led to a ~ 270-meter retreat. This study highlights the vulnerability of Alabama’s shallow coastal aquifers to seawater intrusion due to storm surges and human activities, and demonstrates that combining physics-based models with machine learning approaches can improve groundwater predictions, though its accuracy depends on the availability of site-specific data.