Search Results (564)

The Upper Cretaceous and Jurassic karst aquifers of Sierra de Segura (southern Spain) represent an important groundwater resource within Sierras de Cazorla, Segura, and Las Villas Natural Park (the largest protected area in Spain). The two carbonate aquifer systems are separated by the low-permeability Utrillas Formation, composed mainly of sands, sandstones, and clay-rich sediments. Hydraulic connectivity between these aquifers remains poorly constrained in the literature. This study evaluated the hydrochemical and isotopic evidence of connectivity between the Upper Cretaceous and Jurassic aquifers using major ions (Na⁺, K⁺, Ca²⁺, Mg²⁺, Cl⁻, NO₃⁻, SO₄²⁻, and HCO₃⁻) and stable water isotopes (δ¹⁸O and δ²H) from 464 groundwater samples collected from 20 springs between May 2020 and October 2023. The hydrochemical results show a progressive increase in electrical conductivity and temperature from the Upper Cretaceous to the Jurassic aquifer, together with higher Mg²⁺, Na⁺, K⁺, Cl⁻, and SO₄²⁻ concentrations in the Jurassic system, indicating greater hydrochemical evolution. Principal Component Analysis (PCA) identified mineralization as the dominant controller of groundwater variability and revealed a hydrochemical gradient from relatively homogeneous Upper Cretaceous groundwater toward more mineralized Jurassic groundwater, with partial overlap between both groups. The convergence of hydrochemical, isotopic, multivariate, and temporal evidence is consistent with the hydraulic connectivity between the two aquifer systems. We propose the “SHOWER EFFECT” as a conceptual hypothesis involving potential groundwater transfer through the Utrillas Formation. However, alternative explanations cannot be excluded, and further tracer, groundwater age, and numerical modeling studies are required to test the proposed mechanism. Full article

Hydrothermal circulation through oceanic lithosphere is a fundamental control on the chemistry of the oceans, yet the compositions of vent fluids vary widely, and their net effect on global elemental cycles remains enigmatic. As seawater percolates down into young oceanic lithosphere, it undergoes a series of water–rock reactions across a broad thermal range, from low-temperature alteration in the recharge zone to high-temperature exchange in the reaction zone, with resulting vent fluids diverging significantly in composition from the initial seawater. Drawing evidence from direct sampling of hydrothermal fluids and vent deposits, laboratory experiments, and modeling, we highlight that variable vent fluid chemistry arises from differences in host-rock lithologies, the nature of the hydrothermal heat source, and pressure-temperature conditions within the hydrothermal system. Building on this foundation, we then examine how these fluids influence global elemental cycles across timescales: their effect on the biological carbon pump, primarily through Fe and Mn fertilization (short timescales), as well as their influence on secular variation in seawater composition, as recorded by carbonates, evaporites, and fluid inclusion records (geological timescales). Regardless of timescales, the evidence compiled here reinforces hydrothermal circulation as a first-order control on ocean chemistry. However, key questions remain open: the relative importance of axial (high-temperature) and ridge flank (low-temperature) processes in global biogeochemical cycles, and the role of additional controls (such as authigenic clay formation and submarine groundwater discharge) in shaping seawater chemistry through time. Full article

Anchors constructed in water-rich sandy-pebble strata require grout systems that can maintain material continuity and transfer tensile force effectively before groundwater-related disturbance weakens the borehole interface. This study investigated a sulphoaluminate cement-based rapid-setting grout (SAC) for PSB high-strength threaded anchors, using an ordinary Portland cement-based grout (OPC) as a reference material. Laboratory central pull-out tests were first conducted on grout cube specimens with different steel-bar diameters and bonded lengths to evaluate the steel–grout bond response. Full-scale field pull-out tests were then performed to examine the anchor–grout–ground response under water-rich ground conditions. LS-DYNA finite element models were calibrated against the laboratory and field results to interpret the governing load-transfer mechanism and to assess the influence of representative stratum resistance. The laboratory tests showed that the steel–grout bond response depended on both interfacial degradation and mortar splitting, indicating that peak bond strength should be interpreted together with failure mode and slip development. In the field tests, all anchors failed by pull-out, and the steel bar and grout body were pulled out together, showing that the full-scale response was governed mainly by the grout–ground interface rather than by steel–grout debonding. The calibrated numerical models reproduced the main load–displacement trends and supported a scale-dependent transition from steel–grout bond control at material scale to grout–ground interface control at field scale. The results provide a basis for evaluating rapid-setting grouts for high-strength anchors in water-rich sandy-pebble ground. Full article

Groundwater quality in semi-arid regions is influenced by interacting geological, climatic, and human factors. This study integrated hydrochemical analysis, ionic relationships, multivariate statistics, Water Quality Index (WQI), and GIS-based spatial analysis to evaluate groundwater quality in Fars Province, southern Iran. A total of 171 groundwater wells were sampled during each of the 2020 and 2021 monitoring campaigns. Hydrochemical diagrams and ionic relationships indicated the predominance of Na–Cl facies and showed that groundwater chemistry is mainly controlled by carbonate and silicate weathering, evaporite dissolution, cation exchange, water–rock interaction, and evaporation–crystallization. Chloro-alkaline indices indicated a mixed cation-exchange system, with positive CAI values predominating regionally and negative values occurring locally. Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) consistently identified groundwater mineralization as the dominant source of hydrochemical variability, characterized by EC, TDS, major ions, and hardness, while bicarbonate and nitrate represented a secondary source of variability reflecting both carbonate-related processes and localized nutrient inputs. Based on WQI, about 48% and 42.7% of the sampled wells were classified as excellent or good in 2020 and 2021, respectively, whereas 26% and about 30% were unsuitable for drinking. Spatial analysis revealed widespread mineralization and enrichment of Na⁺, Cl⁻, and SO₄²⁻, although interpolation results for EC and TDS should be interpreted cautiously and primarily for exploratory visualization of spatial patterns because of their lower predictive performance. In general, regional groundwater quality is governed primarily by natural hydrogeochemical evolution, while localized anthropogenic influences may contribute to nutrient variability. The results provide a basis for targeted monitoring and sustainable groundwater management in semi-arid aquifers. Full article

Hydrological drought, expressed as anomalously low water availability in rivers, aquifers, and reservoirs, poses a growing threat to water security in densely populated regions such as the Metropolitan Region of Sao Paulo (MRSP), Brazil. Characterizing how drought propagates into large-scale terrestrial water storage (TWS) deficits, and how these deficits translate into measurable surface deformation, remains challenging in complex, human-managed hydrological systems such as the Cantareira Water Supply System. This study conducts an integrated, multi-sensor geodetic assessment of drought-related hydrological dynamics in the Cantareira System, combining vertical/LOS ground displacement derived from continuous GPS observations and Sentinel-1 InSAR time series with terrestrial water storage anomalies (TWSAs) from GRACE/GRACE-FO, groundwater level records, reservoir storage, and meteorological drought indicators. Cross-correlation analysis reveals a strong and statistically significant coupling between GRACE-TWSA and GPS-derived vertical displacement, with correlation coefficients of $r=-0.8$ (Upper Tietê basin) and $r=-0.6$ (PCJ basin), consistent with an elastic crustal response to hydrological loading. Reservoir storage in the PCJ basin is similarly correlated with regional TWSA (up to $r=0.7$ for the Jaguari–Jacareí reservoir), reinforcing GRACE’s sensitivity to the main upstream storage component of the Cantareira System. Empirical Orthogonal Function (EOF) decomposition of the InSAR deformation fields, retaining the first four modes (72% of variance in Upper Tietê, 66% in PCJ), further demonstrates that deformation patterns are strongly influenced by hydrogeological controls, with distinct spatial responses between the PCJ basin, where hydroclimatic forcing is more pronounced, and the more urbanized and anthropogenically influenced Upper Tietê basin. The integrated dataset captures major drought episodes between January 2020 and Dicember 2025, demonstrating the capability of combining GPS, InSAR, and GRACE observations to quantitatively link climatic drought forcing, terrestrial water storage deficits, and surface deformation, thereby providing a robust approach for monitoring water storage changes and supporting water resource management in densely populated regions. Full article

Geothermal energy is a critical low-carbon resource in the global carbon neutrality transition, but expanding exploitation has raised growing concerns over geothermal fluid quality degradation and fluoride-related public health risks in the tectonically active coastal region of Guangdong, South China. However, the hydrochemical mechanisms governing fluoride enrichment remain poorly constrained, and conventional qualitative analytical approaches cannot quantitatively disentangle the superimposed effects of multiple subsurface geochemical processes. Based on 20 geothermal groundwater samples, this study integrates hydrochemical characterization, stable hydrogen and oxygen isotope tracing, and positive matrix factorization (PMF) modeling to quantitatively identify dominant hydrochemical processes and decipher the genetic mechanism of fluoride enrichment. The results demonstrate that the geothermal groundwaters belong to Cl–Na hydrochemical facies, with temperatures ranging from 60 °C to 96 °C and total dissolved solids (TDSs) varying from 560 mg/L to 9862 mg/L. Water–rock interaction dominates hydrochemical evolution: congruent dissolution of halite and other evaporite minerals serves as the primary source of bulk salinity, while bidirectional cation exchange on clay mineral surfaces substantially modifies the ionic assemblage. Stable isotope compositions (δD: −47.2‰ to −39.0‰; δ¹⁸O: −7.3‰ to −5.2‰) confirm a dominant meteoric recharge origin, with notable positive ¹⁸O shifts in multiple samples reflecting prolonged deep water–rock interaction with silicate host rocks. Recharge elevations are estimated at 239~682 m, delineating the northwestern medium–low mountain zone as the primary recharge area. Fluoride concentrations (2~13 mg/L) universally exceed the drinking water standard, and their enrichment is governed by a coupled geochemical feedback mechanism: hydrolytic weathering of fluor-bearing silicates releases structural fluoride, while widespread calcite precipitation scavenges aqueous Ca²⁺, weakens the common-ion effect, and promotes fluorite dissolution. The PMF model quantitatively resolves three geochemically meaningful controlling factors with clear process implications. These findings advance the mechanistic understanding of fluoride geochemistry in coastal granitic geothermal systems within the western Pacific tectonic belt, and provide a robust scientific basis for sustainable geothermal resource development and public health risk management. Full article

Nitrate contamination threatens surface water and groundwater quality in karst regions, posing risks to drinking water safety and aquatic ecosystems. Strong surface water–groundwater connectivity in karst recharge areas can accelerate contaminant transport through fractures and conduits. In this study, 166 samples, comprising 100 groundwater samples and 66 surface-water samples, were collected under wet-season, normal-flow, and dry-season conditions from a typical karst recharge area in Fengshan Township, Dafang County, Guizhou Province, China. Hydrochemical analyses, dual nitrate isotope analysis, and isotope-based mixing models were integrated to evaluate potential nitrate source contributions and examine the hydrochemical factors associated with nitrate variability. Groundwater was dominated by Ca–HCO₃ and mixed hydrochemical facies and exhibited relatively stable ionic compositions, whereas surface water showed more diverse facies and greater variability in total dissolved solids, SO₄²⁻, Na⁺, K⁺, and Cl⁻, reflecting a stronger response to external inputs and short-term hydrological processes. NO₃⁻ concentrations ranged from 0.02 to 16.24 mg/L in groundwater and from 0.00 to 41.20 mg/L in surface water, with mean concentrations of 3.07 and 4.38 mg/L, respectively. Mixing-model estimates identified manure and sewage (47%) and soil nitrogen (30%) as the leading potential contributors to groundwater nitrate, whereas manure and sewage had the largest estimated contribution to surface-water nitrate (68%). Given the overlap among the isotopic signatures of potential sources, these percentages represent probable source combinations rather than exact apportionments. The absence of consistent covariation between NO₃⁻ and Cl⁻ indicated that nitrate transport was not controlled solely by conservative mixing but was jointly regulated by source-input intensity, rapid surface-runoff responses, conduit transport, subsurface mixing, dilution, and water–rock interactions. Statistical modeling further showed that groundwater NO₃⁻ variability was associated with the major-ion composition, whereas surface-water NO₃⁻ variability was partly explained by a multiple regression model incorporating SO₄²⁻ and Cl⁻. Together, these findings support a conceptual source-to-transport framework involving external inputs, rapid surface-water responses, karst conduit transport, subsurface mixing, and water–rock interaction. This study provides insight into contrasting potential nitrate sources and transport processes in connected karst surface water-groundwater systems and supports pollution-source tracing, recharge-area management, and drinking-water source protection. Full article

Karst piedmont fault overflow springs are widely developed in structurally controlled, basin-margin settings, where basin-bounding faults obstruct regional groundwater flow. However, the coupled fault blocking, fault conduction, and caprock sealing mechanisms governing their genesis remain insufficiently quantified. This study investigates the Shentou Spring system in Shanxi Province, North China—a typical piedmont fault overflow spring—to develop a three-dimensional genetic model characterised by coupled blocking, conduction, and overflow processes. Integrating borehole datasets, multi-year groundwater level monitoring records, hydrochemical and isotopic measurements, and detailed structural mapping, this study identifies three key controlling mechanisms. First, spatial variations in the throw of the Mayi Fault control fault blocking efficiency, partitioning the fault zone into complete barrier and semi-permeable segments, which underpins the incomplete drainage behaviour of the spring system. Second, the Gengzhuang Fault intersects the high-permeability Qilihe and Yuanzihe groundwater flow zones, acting as the primary conduit that transports groundwater from distant recharge areas to the discharge zone. Third, the Quaternary caprock in the discharge area features a critical thickness threshold of approximately 30 m; confined karst groundwater breaches the overlying caprock and forms spring outlets where caprock thickness falls below this threshold. The proposed tripartite coupled model provides a semi-quantitative framework for interpreting the genesis of piedmont fault overflow springs. In practical terms, it supports the delineation of fault-conduit protection zones and the design of long-term water-quality monitoring networks along fault-controlled flow paths. Full article

Karst groundwater systems are characterized by highly heterogeneous flow networks, resulting in complex responses of groundwater levels to precipitation variability. The Jinan Spring Basin, one of the most representative karst spring systems in northern China, has experienced substantial changes in spring discharge due to variations in precipitation, groundwater exploitation, and hydrogeological conditions. However, the temporal scales at which precipitation signals control groundwater-level fluctuations and the mechanisms governing their transmission within the karst aquifer remain poorly understood. In this study, daily precipitation data from 30 meteorological stations and groundwater-level records at Baotu Spring during 2016–2018 were analyzed using global wavelet spectrum (GWS) and wavelet transform coherence (WTC) approaches. The dominant precipitation cycles, scale-dependent precipitation–groundwater relationships, and phase-derived groundwater response lags were quantified to reveal the hydrological response characteristics of the Jinan karst system. Three prominent precipitation periods were identified at 17.37, 29.22, and 330.57 days. Groundwater responses presented clear temporal-scale dependence, with short-period signals showing rapid but localized responses, while intermediate and long-period signals demonstrated stronger and more persistent coherence. The percentage of significant coherence area (PASC) increased from 23.50% at the 0–17.37 day scale to 64.28% at the 29.22–330.57 day scale, indicating that accumulated precipitation rather than individual rainfall events exerts the dominant control on groundwater-level variations. The spatial distribution of response lags revealed that rapid responses (17.37 days) mainly occurred in the southern recharge areas, reflecting preferential recharge through well-developed karst conduits. Intermediate responses (29.22 days) showed a progressive increase in lag time from south to north, indicating the influence of regional groundwater flow and aquifer storage. Long-period responses (330.57 days) were locally enhanced near major faults, suggesting structural controls on deeper groundwater circulation. This study reveals that precipitation signals in the Jinan Spring Basin are transmitted through multiple groundwater circulation pathways with distinct temporal characteristics. The identified multi-scale response patterns provide new insights into the internal structure and hydrological functioning of karst aquifers and offer scientific support for sustainable management of spring water resources. Full article

This study proposes a new method for the topological synthesis of principal component projections and hydrogeochemical stoichiometric equality lines on self-organizing map (SOM) component planes to assess groundwater chemistry forming factors and quality in the Pleistocene unconfined aquifer of the Southern Bug and Sinyukha interfluve area, Ukraine. The hydrogeochemical characteristics clustered by the SOM were further examined using the graphical cross-validation method. The groundwater dataset used in the analysis consisted of 10 parameters (i.e., pH, total dissolved solids, $\mathrm{C}{\mathrm{a}}^{2+}$, $\mathrm{M}{\mathrm{g}}^{2+}$, $\mathrm{N}{\mathrm{a}}^{+}$, ${\mathrm{K}}^{+}$, $\mathrm{H}\mathrm{C}{\mathrm{O}}_3^{-}$, $\mathrm{C}{\mathrm{l}}^{-}$, $\mathrm{S}{\mathrm{O}}_4^{2-}$, and $\mathrm{N}{\mathrm{O}}_3^{-}$) from 91 samples collected during the dry season. Subsequently, for SOM construction, we utilized six log-ratio relationships of milliequivalent ion concentrations. Based on the results, the hydrogeochemical groundwater data were classified into three clusters, which revealed three water types and processes controlling their chemistry: salinity driven by sulfate inputs (Cluster 1), highly salinity driven by nitrate-chloride and sulfate pollution (Cluster 2), and relatively fresh water governed by natural carbonate dissolution and silicate weathering (Cluster 3). The salinity types were identifiable in the northern part of the study area, characterized as the primary zone of initial intense pollution. High salinity types were identified in the eastern and southeastern parts of the territory (with delayed water exchange), whereas relatively fresh types were identified in the central part (with active water exchange) as well as in the western and southwestern parts. Modeling confirmed that extensive sulfate, nitrate, and chloride contamination led to anthropogenic degradation of the aquifer system. Full article

During the service life of karst tunnels, groundwater containing Ca²⁺ and CO₃²⁻ can migrate along the shotcrete–surrounding rock interface and induce calcite deposition, thereby changing the interfacial material composition and load transfer path. To clarify the effect of this process on interfacial bonding performance, this study used molecular dynamics simulations to construct CSH–SiO₂, SiO₂–calcite, CSH–calcite, and CSH–calcite–SiO₂ interface models. The interfacial density distribution, radial distribution function, number of hydrogen bonds, interaction energy, and normal tensile failure behavior were analyzed. The results show that all four models reached stable energy plateaus after relaxation, and clear atomic density overlap and short-range RDF peaks appeared in the interfacial regions. These descriptors indicate short-range contact and possible Ca–O electrostatic attraction, hydroxyl-related hydrogen bonding, and carbonate-associated interactions between calcite and both SiO₂ and CSH surfaces. Approximately 80 hydrogen bonds were formed at the SiO₂–calcite interface, approximately 32 at the CSH–calcite interface, and approximately 59 in total for the two hydrogen bond subtypes at the SiO₂–CSH interface, indicating that the hydroxyl state of different substrate surfaces controls the interfacial hydrogen bond network. Interaction energy analysis shows that the single CSH–calcite interface has the strongest interaction (−51,753.6 kcal/mol), approximately 1.90 times that of the SiO₂–CSH interface and 16.43 times that of the SiO₂–calcite interface. However, in the three-layer composite model, the interaction energy on the CSH–calcite side is only approximately 28.0% of that on the SiO₂–calcite side, suggesting that a continuous calcite interlayer introduces asymmetric interfacial constraints. Tensile simulations further show that the SiO₂–calcite model has the highest peak stress (approximately 3.23 GPa) and exhibits brittle failure, whereas failure in CSH-containing systems is more likely to transfer into the CSH layer or weakly connected regions. These results indicate that calcite deposition does not simply strengthen or weaken the interface. Instead, within the two idealized endpoint configurations tested here, its effect depends on deposition continuity, the surface chemistry of the two substrates, and the weak links within the serial interface. This study provides a nanoscale theoretical basis for evaluating relative trends in the long-term service performance of shotcrete–surrounding rock interfaces, and for guiding future multiscale validations of drainage and waterproofing measures in karst tunnels. Full article

As the largest inland river basin in China’s extremely arid region, the stability of the groundwater–vegetatifon system in the Tarim River Basin is crucial for the consolidation of the ecological security barrier in the northwest. To reveal the evolution law of groundwater storage in the watershed from 2003 to 2024 and its response mechanism to vegetation dynamics, this study is based on GRACE gravity satellite, GLDAS land surface assimilation and MODIS remote sensing data. The Theil Sen trend analysis, Hurst index, spatiotemporal Granger causality test, and standardized multiple linear regression model are integrated to systematically analyze the spatiotemporal heterogeneity, future evolution trend, and multi-driving factor contribution pattern of groundwater storage (GWSA) in the watershed. The results showed that: (1) During the study period, the GWSA of the watershed showed a significant downward trend, with a rate of −3.5 mm/a, and experienced a spatial redistribution process of “comprehensive loss local recovery southern compensation northern loss”. The northern and peripheral regions faced new depletion risks. (2) The vegetation condition continues to improve, and the VCI gradually rises from the low to medium range, but the spatial heterogeneity increases synchronously; there is a significant spatial positive correlation between VCI and GWSA, with only a strong lag driving effect in the southwestern region (F > 40). The explanatory power of vegetation factors for groundwater in other regions is limited. (3) Future trend predictions show that over 70% of the region will continue in the direction of historical changes, and the continuous loss trend in the north is difficult to reverse. (4) There is significant spatial differentiation in the contribution rate of driving factors: vegetation conditions (VCI) are the dominant factor, controlling 57.53% of the watershed edge and eastern region; precipitation and temperature dominate the central region (24.94%) and southwestern desert areas (17.53%), respectively. The research results can provide scientific basis for differentiated ecological water delivery and refined management of water resources in the Tarim River Basin. Full article

Artificial intelligence (AI) is increasingly used in water research. However, many AI models, particularly complex machine learning models, often generate outcomes that are difficult for humans to interpret. Explainable artificial intelligence (XAI) has been developed to address these challenges by providing transparent and human-interpretable explanations of model behavior and predictions. We conducted a structured narrative review using predefined searches of Web of Science Core Collection and Scopus to synthesize empirical XAI applications across six water-research domains: hydrological processes, water quality and pollution, groundwater systems, urban water systems, climate–water interactions, and water and wastewater treatment. The review covers feature-importance methods, SHapley Additive exPlanations (SHAP), Local Interpretable Model-agnostic Explanations (LIME), partial dependence plots (PDPs), individual conditional expectation (ICE) plots, accumulated local effects (ALE) plots, counterfactual explanations, and deep-learning attribution methods. Building on previous reviews and perspectives focused on particular water domains or methodological priorities, we provide a cross-domain synthesis of XAI spanning natural and engineered water systems, with emphasis on method selection, model and data compatibility, explanation reliability, and operational implementation. These capabilities, however, must be interpreted with appropriate caution because XAI explanations remain conditional on the data, fitted model, and explanation method, and therefore should not be treated as evidence of causal mechanisms or environmental controls. Recognizing these limitations, we provide practical guidance for selecting and evaluating XAI methods and outline priorities for developing reliable, scalable, and operationally useful AI systems for water research and management. Full article

This article presents a scoping review of the literature on digital twins (DTs) for sustainable groundwater resources management, which constitutes a very recent and rapidly expanding research field, with literature moving quickly from conceptual frameworks to application-oriented systems. The literature, selected through the PRISMA 2020 methodology, is organized into seven sub-topics: AI and ML foundations, digital twin architectures and frameworks, aquifer-scale DT applications, agricultural and water–energy–food (WEF) nexus DTs, basin and urban water DTs, sensing, monitoring and IoT infrastructures, and governance, resilience and socio-hydrology. This structure shows how the field is shifting from monitoring and prediction toward integrated decision support, where process-based models, machine learning surrogates, real-time sensing and optimization are combined to support drought mitigation, saltwater intrusion control, irrigation management, climate adaptation and basin-scale planning. Across the reviewed studies, the most recurrent contributions are the construction of hybrid model architectures, the use of DTs to close the loop between observation and control, and the growing recognition that groundwater management must incorporate governance, stakeholder decision-making and socio-hydrological feedbacks. At the same time, the literature still faces key limitations, especially uncertainty quantification, interoperability between models and data streams, transferability to data-scarce settings and limited validation under real operational conditions. Future research should therefore focus on physics-informed and explainable AI, federated and scalable DT architectures, stronger coupling with socio-hydrological and governance frameworks, and more field-tested implementations that can demonstrate robust performance across diverse hydrogeological and institutional contexts. Full article

Draining peatlands for agricultural purposes accelerates land subsidence, greenhouse gas emissions, and the degradation of surrounding wetlands. To achieve sustainable peatland agriculture, land management must consider not only crop productivity but also the global environment. Peatlands account for approximately 1% of Japan’s land area, with about 61% of that 1% located in Hokkaido. This review summarizes the history of agricultural land use on peatlands in Japan and efforts to address land subsidence, greenhouse gas emissions, and the degradation of wetlands surrounding farmland, focusing primarily on case studies from Hokkaido. To allow peatlands to be used for agriculture, drainage, and mineral soil dressing have been carried out. The drying, shrinkage, consolidation, and decomposition of peat resulting from drainage cause land subsidence. Paddy rice cultivation and cyclic irrigation are land management methods that balance the mitigation of land subsidence with food production. Drainage from farmland degrades the vegetation of any surrounding wetlands. On forage-harvesting farmland, buffer zones are established between the farmland and any surrounding wetlands to mitigate the degradation of these wetlands. Lowering the groundwater level increases CO₂ and N₂O emissions, while raising it increases CH₄ emissions. A global meta-analysis has reported that maintaining the groundwater level between −20 cm and −40 cm results in the lowest total greenhouse gas emissions. However, data on greenhouse gas emissions from peatlands used for agricultural purposes with mineral soil coverage in Japan and the reduction in such emissions are limited. In Hokkaido, the introduction of groundwater level control systems has recently been progressing; the challenge of verifying the effectiveness of subsidence control and peat decomposition control through subsurface irrigation on fields other than paddy fields remains. Full article