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Vietnam Mekong Delta (VMD), the country’s most important food basket, is constantly threatened by drought-infused salinity intrusion (SI). The SI disaster of 2020 is recognized as the worst in recent decades, hence inspiring this perspective article. The authors’ viewpoints on the disaster’s impacts and causes are presented. The arguments presented are mainly drawn from (i) up-to-date publications that report on the recent SI intensification in the VMD and (ii) the power spectral analysis results using water level data. We verified the intensifying SI in the VMD both in its frequency and magnitude and remarked on four of the key SI drivers: (i) upstream hydropower dams, (ii) land subsidence, (iii) the relative sea-level rise, and (iv) riverbed sand mining. Also, a non-exhaustive yet list of recommendable management implications to mitigate the negative effects of the SI is contributed. The mitigation measures must be realized at multiple scales, ranging from pursuing transboundary water diplomacy efforts to managing internal pressures via developing early warnings, restricting illegal sand mining activities, alleviating pressures on groundwater resources, and diversifying agriculture.

Soil salinization and waterlogging are critical environmental issues affecting agricultural productivity and cultural heritage preservation, particularly in arid regions. This study investigated soil degradation processes in the archaeologically and agriculturally significant northeastern Nile Delta of Egypt. The objective was to assess the severity of soil degradation and identify key drivers related to water resources and soil characteristics to aid in the development of management strategies. The research employed a multi-faceted approach, including hydrochemical analyses (of groundwater, irrigation water, and soil), water quality indices calculations, statistical analyses, and satellite data. The results revealed high levels of soil salinization in the northern and central areas, with 64% of soil samples classified as strongly and very strongly saline. Soil chemistry indicated salinization sources linked to sodium chloride dominance. Satellite data from Sentinel-2 images and SRTM digital elevation data showed widespread severe waterlogging in the northern lowlands. The Irrigation Water Quality Index (IWQI) values indicated that 87.5% of irrigation water samples posed severe restrictions due to high salinity and sodium hazards, which were mismatched with the low soil permeability observed in 81% of the collected samples exhibiting clay texture and covering most of the study area. Furthermore, shallow groundwater at depths of 0.5–3 m with high salinity was detected, where total dissolved solids exceeded 20,000 mg/L, and Na-Cl water types prevailed, indicating saltwater intrusion. A strong positive correlation ( r  > 0.83) was found between shallow saline groundwater and soil salinity. The combination of poor irrigation water quality, shallow saline groundwater tables, and low-permeability soils created a synergistic effect that severely compromised soil health and agricultural productivity. It also posed severe risks to the structural integrity of archaeological sites and buried artifacts through accelerated physical and chemical weathering processes. This necessitates an urgent mitigation strategy to combat soil degradation in this critical area.

Irrigation with saline groundwater has become necessary to overcome freshwater scarcity in the agricultural industry in arid areas. However, the effects of long-term saline groundwater irrigation on soil salinity and bacterial diversity have rarely been examined. In this study, a Lycium ruthenicum field was divided into two parts and subjected to flooding irrigation with saline groundwater (pH 7.81, total salinity 0.95 g L −1 ) and surface water (pH 7.76, total salinity 0.36 g L −1 ) for 8 years. After 8 years of irrigation, the soil salinity and salt ion content (i.e., Na + , Mg 2+ , K + , Ca 2+ , Cl − and CO 3 2− ) in the groundwater irrigation group were significantly greater than those in the surface water irrigation group ( p  < 0.001), with notable accumulation in the topsoil (0–5 cm) ( p  < 0.01). The bacterial community structure differed between the surface water and groundwater irrigation groups. Salt-tolerant bacterial groups (e.g., Balneolaceae and Halomonadaceae) and species (e.g., the marine bacterium JK1007, the bacterium YC-LK-LKJ35, and Methylohalomonas lacus ) dominated in the groundwater irrigation environment. Additionally, bacterial communities were associated primarily with soil salt ions (RV = 0.66, p  < 0.001). The characteristic bacterial taxa in long-term groundwater irrigation soils were salt-tolerant species (e.g., the marine bacterium JK1007, the bacterium YC-LK-LKJ35, and Methylohalomonas lacus). These findings suggest that salinity is the key factor driving differences in bacterial community structure between long-term groundwater and surface water irrigation. The long-term use of surface water and groundwater for irrigation has different impacts on soil environments, with groundwater irrigation having a more pronounced negative effect. Highlights. The long-term effects of this practice on soil salt accumulation and bacterial diversity were examined. This study provides potential applications for sustainable land management in similar ecological contexts. Groundwater irrigation is characterized by saline-tolerant keystone species. Salinity filtering was used to determine the pattern of bacterial community construction. Highlights The long-term effects of this practice on soil salt accumulation and bacterial diversity were examined. This study provides potential applications for sustainable land management in similar ecological contexts. Groundwater irrigation is characterized by saline-tolerant keystone species. Salinity filtering was used to determine the pattern of bacterial community construction.

Pretreatment of raw feed water is an essential step for proper functioning of a reverse osmosis (RO) desalination plant as it minimizes the risk of membrane fouling. Conventional pretreatment methods have drawbacks, such as the potential of biofouling, chemical consumption, and carryover. Non-conventional membrane-based pretreatment technologies have emerged as promising alternatives. The present review focuses on recent advances in MF, UF, and NF membrane pretreatment techniques that have been shown to be effective in preventing fouling as well as having low energy consumption. This review also highlights the advantages and disadvantages of polymeric and ceramic membranes. Hybrid technologies, which combine the benefits of conventional and non-conventional methods or different membranes, are also discussed as a potential solution for effective pretreatment. The literature that has been analyzed reveals the challenges associated with RO pretreatment, including the high cost of conventional pretreatment systems, the difficulty of controlling biofouling, and the production of large volumes of wastewater. To address these challenges, sustainable hybrid strategies for ceramic membrane-based systems in RO pretreatment are proposed. These strategies include a thorough assessment of the source water, removal of a wide range of impurities, and a combination of methods such as adsorption and carbon dioxide with a low amount of antiscalants. Furthermore, the suggestion of incorporating renewable energy sources such as solar or wind power can help reduce the environmental impact of the system. A pilot study is also recommended to overcome the difficulties in scaling ceramic systems from laboratory to industrial scale. The review also emphasizes the importance of conducting an effective assessment to suggest a treatment for the brine if needed before being discharged to the environment. By following this framework, sustainable, energy-efficient, and effective solutions can be recommended for pretreatment in desalination systems, which can have significant implications for water scarcity and environmental sustainability.

Background Currently, using unconventional water sources in agriculture has become necessary to face overpopulation worldwide. Therefore, a pot experiment was carried out to evaluate the effects of irrigation with saline water in the presence of co-applied wood chips biochar (WCB) with chemical fertilizers on physicochemical properties and nutrient availability as well as growth parameters, and yield of red radish ( Raphanus sativus L.) grown in the saline sandy soil. Methods The WCB was added to the saline sandy soil at levels of 0 (control), 2.5, and 5% w/w. Then, this soil was cultivated by red radish plants and irrigated with saline water (5 dS m − 1 ). This experiment was performed in a randomized complete block design with three replicates. Results Compared with the control treatment, WCB treatments increased significantly soil water holding capacity by 34.8% and 73.2% for levels of 2.5 and 5%, respectively. Soil pH decreased significantly in all WCB treatments. The relative increase in the total available nitrogen over the control was 30.1 and 103.5% for 2.5 and 5% wood chips biochar, respectively. Compared to the control, applying WCB at 2.5% led to an increase in the fresh root weight of red radish plants by 142.7%, while 5% caused a decrease in the fresh root weight of red radish plants by 29.4%. Conclusion Recently, WCB represents an interesting approach to the rehabilitation of saline soils and the management of using saline water sources. It is recommended that combined application of WCB at a level of 2.5% with chemical fertilizers in order to improve red radish growth and nutrient retention in the saline sandy soil which preserves the ecosystem as well as increases productivity leading to the reduction of costs. Highlights Wood chips biochar applications into saline soil increased water holding capacity. Incorporated wood chips biochar with chemical fertilizers enhanced the availability of nitrogen and potassium in saline soil. Combining wood chips biochar at 2.5% with chemical fertilizers in saline soil improved yield parameters of red radish under saline water irrigation. Wood chips biochar at 2.5% incorporated with chemical fertilizers represents a promising strategy in saline agriculture.

Saltwater intrusion is the leading edge of sea-level rise, preceding tidal inundation, but leaving its salty signature far inland. With climate change, saltwater is shifting landward into regions that previously have not experienced or adapted to salinity, leading to novel transitions in biogeochemistry, ecology, and human land uses. We explore these changes and their implications for climate adaptation in coastal ecosystems. Biogeochemical changes, including increases in ionic strength, sulfidation, and alkalinization, have cascading ecological consequences such as upland forest retreat, conversion of freshwater wetlands, nutrient mobilization, and declines in agricultural productivity. We explore the trade-offs among land management decisions in response to these changes and how public policy should shape socioecological transitions in the coastal zone. Understanding transitions resulting from saltwater intrusion—and how to manage them—is vital for promoting coastal resilience.

INTRODUCTION TO DESALINATION Explore the principles, methods, and applications of modern desalination processes Introduction to Desalination: Principles, Processes, and Calculations delivers a comprehensive and robust exploration of desalination highlighted with numerous illustrative examples and calculations.

Projected sea-level rise will raise coastal water tables, resulting in groundwater hazards that threaten shallow infrastructure and coastal ecosystem resilience. Here we model a range of sea-level rise scenarios to assess the responses of water tables across the diverse topography and climates of the California coast. With 1 m of sea-level rise, areas flooded from below are predicted to expand ~50–130 m inland, and low-lying coastal communities such as those around San Francisco Bay are most at risk. Coastal topography is a controlling factor; long-term rising water tables will intercept low-elevation drainage features, allowing for groundwater discharge that damps the extent of shoaling in ~70% (68.9–82.2%) of California’s coastal water tables. Ignoring these topography-limited responses increases flooded-area forecasts by ~20% and substantially underestimates saltwater intrusion. All scenarios estimate that areas with shallow coastal water tables will shrink as they are inundated by overland flooding or are topographically limited from rising inland.Sea-level rise raises water tables, causing flooding from below and saltwater intrusion. A modelling study predicts that coastal California groundwater flooding will expand 50–130 m inland with 1 m of sea-level rise, with areal flooding extent strongly dependent on topography and drainage capacity.

The Mekong delta is Vietnam’s premier rice growing region, forming the livelihood basis for millions of farmers. At the same time, the region is facing various challenges, ranging from extreme weather events, saline water intrusion, and other anthropogenic pressures. This study examines how saline water intrusion and drought have affected rice yield in the Vietnamese Mekong Delta (VMD). Applying the Standardized Precipitation Index (SPI) and the maximum and minimum values of annual average salinity, we spatially examine the effects of drought and saline water intrusion on rice yields over a 40-year period (1980–2019). Our results highlight that 42% of the natural land area of the VMD has experienced increased drought occurrence during the winter-spring (WS) rice cropping season, while certain inland regions have additionally experienced increased drought occurrence during the summer-autumn (SA) rice cropping season. The Tri Ton Station, which has a significant Sen’s slope of −0.025 and a p-value of 0.05, represents an upstream semi-mountainous part of the delta, indicative of a rising severity of reoccurring drought. It should be noted that the yield decreases during the summer-autumn season as the positive SPI_SA increases. Salinity, on the other hand, is associated with SPI_WS during the winter-spring season. Our results highlight the need for improved evidence-based planning and investments in priority adaptation for both sustainable water infrastructure and to improve system resilience.

Saltwater intrusion is a prevalent global environmental issue that detrimentally impacts coastal groundwater aquifers. This problem is exacerbated by climate change and increased groundwater abstraction. Employing physical barriers proves effective in mitigating saline water intrusion. In this study, a validated numerical simulation model is utilized to assess the impact of aquifer stratification on the effectiveness of mixed physical barriers (MPBs) and their response to structural variations. Additionally, the performance of MPBs was compared with that of single physical barriers in a laboratory-scale aquifer. Three different configurations were replicated, comprising two stratified aquifers (HLH and LHL) and a homogenous reference aquifer (H). The results demonstrate that MPBs are efficient in decreasing the saltwater penetration length in the investigated cases. The reductions in penetration length were up to 65% in all cases. The removal efficacy of residual saline water for MPBs exceeded that of the subsurface dam by 2.1–3.3 times for H, 2.1–3.6 times for HLH, and 8.3 times for LHL conditions, while outperforming the cutoff wall by 38–100% for H, 39–44% for HLH, and 2.7–75% for LHL. These findings are of importance for decision-makers in choosing the most appropriate technique for mitigating saline water intrusion in heterogeneous coastal aquifers.