Search Results (298)

This study presents a hybrid approach to hydrological forecasting by integrating the physically based Soil and Water Assessment Tool (SWAT) model with Prophet time-series modeling and machine learning–based multi-output regression. Applied to the Cahaba watershed, the objective is to predict key environmental variables (precipitation, evapotranspiration (ET), potential evapotranspiration (PET), and snowmelt) and their influence on hydrological responses (surface runoff, groundwater flow, soil water, sediment yield, and water yield) under present (2010–2022) and future (2030–2042) climate scenarios. Using SWAT outputs for calibration, the integrated SWAT-Prophet-ML model predicted ET and PET with RMSE values between 10 and 20 mm. Performance was lower for high-variability events such as precipitation (RMSE = 30–50 mm). Under current climate conditions, R² values of 0.75 (water yield) and 0.70 (surface runoff) were achieved. Groundwater and sediment yields were underpredicted, particularly during peak years. The model’s limitations relate to its dependence on historical trends and its limited representation of physical processes, which constrain its performance under future climate scenarios. Suggested improvements include scenario-based training and integration of physical constraints. The approach offers a scalable, data-driven method for enhancing monthly water balance prediction and supports applications in watershed planning. Full article

In recent years, China has experienced growing impacts from extreme weather events, emphasizing the importance of understanding regional atmospheric moisture dynamics, particularly Precipitable Water Vapor (PWV), to support sustainable environmental and urban planning. This study utilizes ten years (2013–2022) of Global Navigation Satellite System (GNSS) observations in typical cities in eastern China and proposes a comprehensive multiscale frequency-domain analysis framework that integrates the Fourier transform, Bayesian spectral estimation, and wavelet decomposition to extract the dominant PWV periodicities. Time-series analysis reveals an overall increasing trend in PWV across most regions, with notably declining trends in Beijing, Wuhan, and southern Taiwan, primarily attributed to groundwater depletion, rapid urban expansion, and ENSO-related anomalies, respectively. Frequency-domain results indicate distinct latitudinal and coastal–inland differences in the PWV periodicities. Inland stations (Beijing, Changchun, and Wuhan) display annual signals alongside weaker semi-annual components, while coastal stations (Shanghai, Kinmen County, Hong Kong, and Taiwan) mainly exhibit annual cycles. High-latitude stations show stronger seasonal and monthly fluctuations, mid-latitude stations present moderate-scale changes, and low-latitude regions display more diverse medium- and short-term fluctuations. In the short-term frequency domain, GNSS stations in most regions demonstrate significant PWV periodic variations over 0.5 days, 1 day, or both timescales, except for Changchun, where weak diurnal patterns are attributed to local topography and reduced solar radiation. Furthermore, ERA5-derived vertical temperature profiles are incorporated to reveal the thermodynamic mechanisms driving these variations, underscoring region-specific controls on surface evaporation and atmospheric moisture capacity. These findings offer novel insights into how human-induced environmental changes modulate the behavior of atmospheric water vapor. Full article

Understanding soil infiltration at the watershed level is crucial to hydrological studies, as it significantly influences surface runoff, groundwater replenishment, and ecosystem sustainability. Research in this area—particularly employing the Soil and Water Assessment Tool (SWAT)—has seen sustained scholarly interest, with an upward trend in related publications. This study analyzed 141 peer-reviewed articles from the Web of Science (WOS) Core Collection. By applying bibliometric techniques through CiteSpace visualization software, it explored the key themes and emerging directions in the use of the SWAT model for soil infiltration studies across watersheds. Findings revealed that this field integrates multiple disciplines. Notably, the Journal of Hydrology and Hydrological Processes emerged as two of the most impactful publication venues. Researchers and institutions from the United States, China, and Ethiopia were the core contributors to this area. “Land use” and “climate change” are currently the hotspots of interest in this field. There are three development trends: (1) The scale of research is continuously expanding. (2) The research subjects are diversified, ranging from initially focusing on agricultural watersheds to surrounding areas such as hillsides, grasslands, and forests. (3) The research content becomes more systematic, emphasizing regional coordination and ecological sustainability. Overall, the research on soil infiltration at the watershed scale using the SWAT model presents a promising and thriving field. This study provides researchers with a framework that objectively presents the research hotspots and trends in this area, serving as a valuable resource for advancing academic inquiry in this domain. Full article

Sulfate as a potential pollution source in the water environment of the basin, identifying sulfate sources and migration mechanisms is essential for protecting the water environment and ensuring sustainable water management. Liuyang River is a primary tributary of the Xiangjiang River. It has experienced progressively intensifying anthropogenic influences in recent decades, manifested by sustained sulfate concentration increases. However, the sulfate sources and their contributions were not clear. This study used hydrochemistry and multi-isotopes methods combined with Simmr model to study the hydrochemical characteristics, sulfate sources, and migration–transformation processes of surface water and groundwater. The results showed that the hydrochemical types of surface water were HCO₃-Ca and HCO₃·SO₄-Ca·Mg, and groundwater were HCO₃-Ca, HCO₃-Ca·Mg, and HCO₃·SO₄-Ca. Ions in the water primarily originated from carbonate and silicate rocks dissolution and sulfide oxidation, augmented by mining operations, sewage discharge, and chemical production. The analyses of hydrochemistry, isotopes, and Simmr model revealed that surface water sulfate originated from soil sulfate (35.70%), sulfide oxidation (26.56%), sewage (16.58%), and atmospheric precipitation (12.45%). Groundwater sulfate was derived predominantly from sewage (34.96%), followed by soil sulfate (28.09%), atmospheric precipitation (17.35%), and sulfide oxidation (12.25%). Sulfate migration and transformation were controlled by the natural environment and anthropogenic impacts. When unaffected by human activities, sulfate mainly originated from soil and atmospheric precipitation, relating to topography, geological conditions, agricultural activities, and precipitation intensity. However, in regions with intense human activities, contributions from sewage and sulfide oxidation significantly increased due to the influences of mining and industrial activities. Full article

The latest FAO report indicates that aquaculture accounts for 51% of the global production volume of fish and seafood. However, despite the continuous growth of this activity, there is evidence of the excessive use of groundwater in its production processes, as well as pollution caused by nutrient discharges into surface waters due to the water exchange required to maintain water quality in fishponds. Given this context, the objectives of this study were as follows: (1) to review which emergent and floating plant species are used in constructed wetlands (CWs) for the bioremediation of aquaculture wastewater; (2) to identify the aquaculture species whose wastewater has been treated with CW systems; and (3) to examine the integration of CWs with recirculating aquaculture systems (RASs) for water reuse. A systematic literature review was conducted, selecting 70 scientific articles published between 2003 and 2023. The results show that the most used plant species in CW systems were Phragmites australis, Typha latifolia, Canna indica, Eichhornia crassipes, and Arundo donax, out of a total of 43 identified species. These plants treated wastewater generated by 25 aquaculture species, including Oreochromis niloticus, Litopenaeus vannamei, Ictalurus punctatus, Clarias gariepinus, Tachysurus fulvidraco, and Cyprinus carpio, However, only 40% of the reviewed studies addressed aspects related to the incorporation of RAS elements in their designs. In conclusion, the use of plants for wastewater treatment in CW systems is feasible; however, its application remains largely at the experimental scale. Evidence indicates that there are limited real-scale applications and few studies focused on the reuse of treated water for agricultural purposes. This highlights the need for future research aimed at production systems that integrate circular economy principles in this sector, through RAS–CW systems. Additionally, there is a wide variety of plant species that remain unexplored for these purposes. Full article

This study was carried out to fill the present research gap in the study area by assessing water chemistry, potential heavy metal contamination, and the associated health risk evaluation that goes along with it in surface water bodies and groundwater in the NE of Maramureș County, near the Tisa River. The main methods we applied were Piper, Ficklin–Caboi, and Gibbs diagrams for determining the water typology and chemistry, the Overall Water Quality Index (OWQI) and vegetation cover to determine the water quality, a contamination index for analyzing the contamination degree, and a human health risk assessment through water ingestion after exposure of children and adults. This article’s main findings specify that waters were characterized and classified into the CaMgHCO₃⁻ dominant category of water type, with precipitation, agricultural, and domestic inputs, related to the Cl⁻ (mean ranging between 1.01–5.65 mg/L) and NO₃⁻ (mean ranging between 2.23–5.52 mg/L) content. The OWQI scores indicated excellent quality, below the critical value, ranging between 0.70 and 6.57. The applied risk assessment indicated that the daily intake of toxins is higher in the case of children than in adults, up to four and five times. The hazard quotient scores, ranging between 0.00093 and 0.248 for adults and between 0.0039 and 1.040 for children, indicated that if consumed, the studied waters can pose potential negative effects on children. Full article

High levels of pesticide use are associated with intensive crop production. Pesticides are increasingly prevalent in surface and groundwater, which is a major environmental concern. Various methods have been proposed to improve the retention and/or degradation of pesticides in soils. These methods are mainly based on soil adaptation with organic wastes to mitigate soil and water pollution. In addition, there has recently been increased interest in assessing the influence of organic waste additions on pesticide movement in soils with low contents of organic matter. Agriculture and related industries generate large amounts of waste each year. Because of their components, they have the great ability to produce high-value products for environmental restoration. This study reports on the influence of four different agro-industrial wastes (orange peel, beer bagasse, grape pomace, and gazpacho waste) used as organic amendments on the leaching of metobromuron and chlorbromuron (phenylurea herbicides) on a silty clay loam soil (gypsic–calcaric regosol) with low organic matter contents from a semiarid area (southeastern Spain). The adsorption, leaching, and dissipation processes of these herbicides were evaluated on a laboratory scale in amended and unamended soils. In addition, the main leaching indices (GUS, LIX, LEACH, M LEACH, LIN, GLI, HI, and ELI) commonly used to assess groundwater protection against pesticide pollution were evaluated. The sorption coefficients (K_OC) increased in the amended soils. Metobromuron was found in leachates in all cases, although a marked reduction was observed in amended soils, while chlorbromuron was mainly retained in soils, especially in the top layer. The disappearance time (DT₅₀) for metobromuron and chlorbromuron in soil ranged from 11 to 56 d and 18 to 95 d, respectively. All indices except GLI categorize metobromuron as mobile or very mobile in unamended soil. For chlorbromuron, GUS, LIX, LEACH, MLEACH, and Hornsby classify this compound as a medium-to-high leache, while GLI and ELI classify it as having low mobility. In amended soils, most indices classify metobromuron as transitioning to mobile, while most indices catalog chlorbromuron as immobile/transition. Full article

The Kundulun River Basin is the most prominent branch of the Yellow River system within the jurisdiction of Baotou City. As an important water source and ecological barrier, its ecological quality is directly related to the ecological security and sustainable development of the surrounding areas. This study selected the Kundulun River Basin in Baotou City as the research area. On the basis of collecting relevant information, a field investigation was conducted on the ecological and geological conditions of the atmospheric surface subsurface Earth system, using the watershed as the survey scope and water as the carrier for the transfer and conversion of materials and energy in the watershed. This study selected the main factors that affect the ecological geological quality of the watershed and established an evaluation model using the analytic hierarchy process, the coefficient of variation method, and the comprehensive analysis method. We have established an ecological geological quality evaluation index system for the Kundulun River Basin. We conducted quantitative evaluation and comprehensive analysis of regional ecological and geological environment quality. The results indicate that ecological environment indicators contribute the most to the ecological quality of the study area, while the impact of human activities on ecological quality is relatively small. From the perspective of evaluation indicators, grassland has the highest weight, followed by precipitation, groundwater depth, forest land, and cultivated land. Approximately 30.26% of the land in the research area is in a state of high or relatively high ecological and geological–environmental quality risk. It can be seen that the overall quality of the ecological geological environment is not optimistic and needs further protection. Full article

With an increasingly more urbanised global population, surface water and groundwater resources are being/have become outpaced by growing demand. The oceans could address this pertinent scarcity issue, once their high-salinity content is removed. Water desalination could thus be a crucial pathway towards addressing global water scarcity. However, conventional desalination is known to be highly energy-intensive, with limited scalability and potentially significant negative environmental impacts. Multi-criteria Decision Making (MCDM) presents a novel approach towards sustainable water desalination based on sustainability-related criteria. The Fuzzy Analytical Hierarchy Process (FAHP) was implemented to determine the most optimal small-scale, modularised, and remote reverse osmosis (RO) desalination plant configurations. Twelve configurations were assessed, based on four plant capacities (50, 100, 150, and 200 m³/day) and three diesel-to-solar photovoltaic energy configurations (100–0%, 75–25%, and 60–40%). The hybridised diesel-to-solar configurations were generally ranked higher, particularly when less reliant on diesel, and at small(er) capacities, in terms of the criteria: sustainability, overall efficiency, and standalone potential while maintaining competitive costs. This can likely be attributed to their relatively lower fuel and energy consumption and associated costs. Further research should aim to consider additional criteria, such as battery cost, as well as life cycle assessments that include transportation-related costs/emissions. Full article

Elucidating the microbial–hydrochemical interactions in distinct functional zones of coal mines holds significant implications for groundwater pollution mitigation strategies in mining regions. Taking Xinji No. 2 Coal Mine as an example, 15 water samples (including surface water, goaf water, sump water, working face drainage, rock roadway water, and coal roadway water) were collected from six surface and underground areas for hydrochemical and microbial detection analysis. The results show that bacterial genera such as Exiguobacterium and Mycobacterium cannot adapt to high-salinity environments with elevated K⁺ + Na⁺ concentrations, showing negative correlation with TDS. Microbial communities related to sulfate serve as important indicators for microbial technology-based pollution control in coal mine groundwater, where sulfate-reducing bacteria (e.g., norank_f__Desulfuromonadaceae) can reduce SO₄²⁻ concentrations and improve mine water quality. Low dissolved oxygen (DO) concentrations lead to decreased abundance of aerobic microorganisms, hindering the formation of stable microbial communities in mines. Affected by mine water quality, the confluence of mine drainage into rivers results in HCO₃⁻ and SO₄²⁻ concentrations at the confluence being higher than upstream, which gradually return to upstream concentrations after entering the downstream. However, due to the influx of nitrogen cycle-related bacteria and organic matter from mine water into surface water, increased microbial physiological activities and carbon sources cause NO₃⁻ concentrations to increase more than tenfold. The formation stages of mine water quality exhibit regional characteristics, with goaf areas showing distinct hydrochemical components and microbial communities compared to other zones. Based on this research, new microbial approaches for groundwater pollution control in coal mining areas are proposed: (1) selecting and cultivating functional microorganisms (such as SRB and organic matter-degrading bacteria) to develop biological materials for mine water remediation; (2) regulating the transformation of elements by adjusting carbon sources and oxygen supply according to indigenous microbial requirements, thereby reducing pollutant concentrations in water bodies. Full article

Groundwater depth has a significant impact on salinization in irrigated areas. In this study, different groundwater depths were controlled via pit tests and we conducted pit tests with different groundwater depths (DGWs) to investigate the relationship between irrigation water volume and salt migration during the crop growth period, as well as the influence of DGW on maize growth and yield. The aim of this study was to determine an appropriate DGW for maize growth in the Hetao Irrigation District, the largest irrigation area of Asia, under the dual goals of water conservation and salt control. The results showed that the upward replenishment of groundwater was 179.60 mm, 139.17 mm, 119.98 mm, 68.62 mm, and 48.38 mm for each respective DGW, i.e., negatively correlated with DGW during the maize growth period. Soil electrical conductivity (EC) was exponentially related to DGW. For DGWs > 1.75 m, surface soil EC decreased significantly and soil EC exhibited less variation with DGW. Moreover, the desalination rate and depth after irrigation were improved at DGW values of 2.00 m and 2.25 m. Shallow DGW values resulted in increased evapotranspiration and intensified crop stress, which reduced water use efficiency. To reduce resource waste and salt stress on crops, we suggest that a DGW of 2.00~2.25 m is more suitable for maize growth and development. These results provide a reference for determining appropriate DGWs for maize growth in salinized irrigation areas. Full article

This study examines runoff variations and their drivers in the Buha and Shaliu Rivers of the Qinghai Lake Basin (1960–2016), a key ecological area in China. Abrupt changes were detected using the Mann–Kendall and cumulative anomaly methods, while the Budyko framework attributed runoff variations to dominant factors. Correlation and grey relational analyses assessed multicollinearity, and a lake water balance model with climate elasticity theory quantified the effects of climate and land surface changes on runoff components and lake levels. Results indicate that the Buha River experienced an abrupt runoff change in 2004, while the Shaliu River exhibited a change beginning in 2003. Based on the trends and abrupt change points of each factor, the study period was divided into four segments: 1960–1993, 1994–2016, 1960–2003, and 2004–2016. The correlation coefficients are significantly different in different periods. The climate elasticity coefficients were as follows: P (precipitation), 1.98; ET₀ (potential evapotranspiration), −0.98; Rn (net radiation), 0.66; T (average temperature), 0.02; U₂ (wind speed at 2 m height), 0.16; RHU (relative umidity), −0.56. The elasticity coefficient of runoff with respect to precipitation is significantly higher than that for other climate variables. Net radiation and relative humidity contribute equally to runoff, while wind speed and temperature have relatively smaller effects. In the Qinghai Lake Basin, runoff is sensitive to precipitation (0.38), potential evapotranspiration (−0.07), and the underlying surface parameter ω (−98.32). Specifically, a 1 mm increase in precipitation raises runoff by 0.38 mm, while a 1 mm rise in potential evapotranspiration reduces it by 0.07 mm. A one-unit increase in ω leads to a significant runoff decrease of 98.32 mm. According to the lake water balance model, climate contributes 88.43% to groundwater runoff, while land surface changes contribute −11.57%. Climate change and land surface changes contribute 93.02% and 6.98%, respectively, to lake water levels. This study quantitatively evaluates the impacts of climate and land surface changes on runoff, providing insights for sustainable hydrological and ecological management in the Qinghai Lake Basin. Full article

Unsustainable groundwater extraction for domestic and agricultural purposes, particularly crop irrigation, is leading to dramatic reductions in the quantity and quality of groundwater in many developing countries, including Ethiopia. Assessing and predicting groundwater responses to hydraulic stress caused by overexploitation related to anthropogenic activities and climate change are crucial for informing water management decisions. The aim of this study is to develop a three-dimensional steady-state groundwater flow model for the Golina River Sub-Basin to understand the relationship between groundwater recharge and groundwater pumping and their impacts under steady-state conditions from the perspective of groundwater management. The model was created using MODFLOW 6 and discretized into 345 rows and 444 columns with a grid resolution of 100 m by 100 m. The subsurface was modeled as two layers: a clastic alluvial layer overlying a weathered and fractured bedrock. The surface-water divide of the Golina River Sub-Basin was treated as a no-flow boundary. The initial values of horizontal hydraulic conductivity ranged from 0.001 m/day for rhyolite to 27.26 m/day for alluvial deposits. The aquifer recharge rates from the WetSpass model ranged from 1.08 × 10⁻³ to 2.25 × 10⁻⁴ m/day, and the discharge rates from the springs, hand-dug wells, and boreholes were 2.79 × 10⁴ m³/day, known flux boundaries. Sensitivity analysis revealed that the model is very sensitive to hydraulic conductivity, moderately sensitive to aquifer recharge, and less sensitive to groundwater pumping. Calibration was performed to match observed and simulated hydraulic heads of selected wells and achieved a correlation coefficient of 0.998. The calibrated hydraulic conductivity ranged from 1.2 × 10⁻⁴ m/day for rhyolite to 20 m/day for gravel-dominated alluvial deposits. The groundwater flow direction is toward the southeast, and the water balance indicates a negligible difference between the total recharge (207,775.8297 m³/day, which is the water entering the aquifer system) and the total pumped volume (207,775.9373 m³/day, which is the water leaving the aquifer system). The scenario analysis showed that an increase in the pumping rate of 25%, 50%, and 75% would result in a decrease in the hydraulic head by 4.64 m, 10.18 m, and 17.38 m, respectively. A decrease in recharge of 25%, 50%, and 75% would instead result in hydraulic-head declines of 6 m, 15.29 m, and 46.97 m, respectively. Consequently, the findings of this study suggest that decision-makers should prioritize enhancing integrated groundwater management strategies to improve recharge rates within the aquifer system of the study area. Full article

At the beginning of human history, surface water, especially from rivers and springs, was the most frequent water supply source. Groundwater was used in arid and semi-arid regions, e.g., eastern Crete (Greece). As the population increased, periodic water shortages occurred, which led to the development of sophisticated hydraulic structures for water transfer and for the collection and storage of rainwater, as seen, for example, in Early Minoan times (ca 3200–2100 BC). Water supply and urban planning had always been essentially related: the urban water supply systems that existed in Greece since the Bronze Age (ca 3200–1100 BC) were notably advanced, well organized, and operable. Water supply systems evolved considerably during the Classical and Hellenistic periods (ca 480–31 BC) and during the Roman period (ca 31 BC–480 AD). Also, early Indian society was an amazing vanguard of technology, planning, and vision, which significantly impacted India’s architectural and cultural heritage, thus laying the foundation for sustainable urban living and water resource management. In ancient Egypt, the main source of freshwater was the Nile River; Nile water was conveyed by open and closed canals to supply water to cities, temples, and fields. Underground stone-built aqueducts supplied Nile water to so-called Nile chambers in temples. The evolution of water supply and urban planning approaches from ancient simple systems to complex modern networks demonstrates the ingenuity and resilience of human communities. Many lessons can be learned from studying traditional water supply systems, which could be re-considered for today’s urban sustainable development. By digging into history, measures for overcoming modern problems can be found. Rainwater harvesting, establishing settlements in proximity of water sources to facilitate access to water, planning, and adequate drainage facilities were the characteristics of ancient civilizations since the ancient Egyptian, Minoan, Mohenjo-Daro, Mesopotamian, and Roman eras, which can still be adopted for sustainability. This paper presents significant lessons on water supply around the world from ancient times to the present. This diachronic survey attempts to provide hydro-technology governance for the present and future. Full article

The Luhai uranium deposit is a large-scale uranium deposit newly discovered in recent years through comprehensive prospecting methods. It is located in the Basaiqi Paleochannel Uranium metallogenic belt of the Erlian Basin and is characterized by its shallow burial and large scale. This paper provides new data on the genetic processes of sandstone-type uranium mineralization through sedimentological and geochemical environmental indicators (such as Fe³⁺/Fe²⁺, organic carbon, total sulfur, etc.), analysis of C-O isotopes of carbonate cements and H-O isotopes of groundwater, and geochemical and mineralogical studies of uranium minerals, iron–titanium oxides (involving backscatter analysis, micro-area chemical composition determination, and elemental surface scanning), and organic matter. Sedimentological analysis shows that the ore- bearing layer in the upper member of the Saihan Formation developed a braided channel within floodplain subfacies, which control the distribution of uranium ore bodies. Uranium mineralogical observations, geochemical environmental indicators, and organic geochemical data indicate that the main reducing agents related to mineralization are pyrite, terrestrial plants, and deep-sourced oil and gas. The δD values of groundwater in the ore-bearing layer range from −95.34‰ to −90.68‰, and the δ¹⁸O values range from −12.24‰ to −11.87‰. For calcite cements, the δ¹⁸O_V-PDB values range from −24‰ to −11.5‰, and the δ¹⁸_OV-SMOW values range from 6.2‰ to 19‰. It was determined that the ore-forming fluid is mainly surface fresh water that entered the strata during the tectonic uplift stage, with local mixing of deep-sourced brine. Based on these data, the main modes of uranium mineralization in the paleochannel were obtained as follows: (1) Redox mineralization occurs due to the reducing medium within the sand body itself and the reduction caused by deep- sourced oil and gas generated from the Tengge’er and Arshan Formations. (2) Mineralization is achieved through the mixing of fluids from different sources. Furthermore, a genetic model related to uranium mineralization in the paleochannels of the Luhai area has been established: favorable uranium reservoirs were formed during the sedimentary period, and during the post-sedimentary stage, reverse structures promoted redox reactions and fluid-mixing-induced mineralization. The research findings can provide guidance for the exploration of paleochannel sandstone-type uranium deposits in other areas of the Erlian Basin. Full article