Pub Date : 2026-03-01Epub Date: 2026-02-01DOI: 10.1016/j.advwatres.2026.105232
Adebayo Sadiq , Kuldeep Singh
Riverbed topography exerts a primary control on hyporheic exchange, yet the combined influence of reach-scale slope curvature and pool-riffle morphology on subsurface flow organization remains poorly quantified. Using a high-resolution, idealized two-dimensional numerical model that couples turbulent river hydraulics with groundwater flow and solute transport, we systematically vary regional slope (S), longitudinal slope curvature (δ), and pool-riffle amplitude (a) and wavelength (λ) to isolate their independent and combined effects on hyporheic processes. We demonstrate that increasing reach-scale convexity—representing knickzone morphology common to mountain streams—generates vertically nested hyporheic flow cells that expand exchange zones up to an order of magnitude. Slope curvature amplifies penetration intensity and flow-path diversity until a threshold (δ ≈ 2–4), beyond which pool-riffle geometry becomes the dominant control. Pool-riffle aspect ratio (a/λ) governs exchange fluxes through a universal power-law scaling, while larger λ deepens flow paths and accelerates dilution, and larger a enhance flushing intensity. These multi-scale interactions produce non-Fickian residence time distributions and distinct mixing regimes. By explicitly linking reach-scale convexity to hyporheic exchange, this study provides a predictive framework for understanding how knickzone morphology and pool-riffle geometry jointly regulate solute retention, offering new guidance for river restoration and corridor management.
{"title":"Slope curvature and pool-riffle interactions drive hierarchical hyporheic exchange: A predictive framework for river corridor management","authors":"Adebayo Sadiq , Kuldeep Singh","doi":"10.1016/j.advwatres.2026.105232","DOIUrl":"10.1016/j.advwatres.2026.105232","url":null,"abstract":"<div><div>Riverbed topography exerts a primary control on hyporheic exchange, yet the combined influence of reach-scale slope curvature and pool-riffle morphology on subsurface flow organization remains poorly quantified. Using a high-resolution, idealized two-dimensional numerical model that couples turbulent river hydraulics with groundwater flow and solute transport, we systematically vary regional slope (<em>S</em>), longitudinal slope curvature (δ), and pool-riffle amplitude (<em>a</em>) and wavelength (<em>λ</em>) to isolate their independent and combined effects on hyporheic processes. We demonstrate that increasing reach-scale convexity—representing knickzone morphology common to mountain streams—generates vertically nested hyporheic flow cells that expand exchange zones up to an order of magnitude. Slope curvature amplifies penetration intensity and flow-path diversity until a threshold (δ ≈ 2–4), beyond which pool-riffle geometry becomes the dominant control. Pool-riffle aspect ratio (<em>a</em>/<em>λ</em>) governs exchange fluxes through a universal power-law scaling, while larger <em>λ</em> deepens flow paths and accelerates dilution, and larger <em>a</em> enhance flushing intensity. These multi-scale interactions produce non-Fickian residence time distributions and distinct mixing regimes. By explicitly linking reach-scale convexity to hyporheic exchange, this study provides a predictive framework for understanding how knickzone morphology and pool-riffle geometry jointly regulate solute retention, offering new guidance for river restoration and corridor management.</div></div>","PeriodicalId":7614,"journal":{"name":"Advances in Water Resources","volume":"209 ","pages":"Article 105232"},"PeriodicalIF":4.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146098394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2026-01-27DOI: 10.1016/j.advwatres.2026.105223
S. Annis , M.G. Badas , G. Mascaro
Urban pluvial flooding is a highly impactful natural hazard whose understanding remains limited by the scarcity of observations. Here, we demonstrated that continuous, spatially distributed, street-level flood depth measurements provide critical information to increase the fidelity of pluvial flooding simulations. We applied the LISFLOOD-FP two-dimensional, rain-on-grid hydrodynamic model to two dense urban basins of 10.9 and 0.8 km2, respectively, in New York City (NYC), where eight sensors from the FloodNet network recorded widespread flooding during three intense storms. We first provided insights into the generation of model domain and net precipitation forcings at the hyperlocal resolution of 1 m, required to quantify flood hazards at the pedestrian and vehicle scale and to support decision-making. We then focused on one event in the larger basin and assessed the performance of three modeling scenarios under the common condition of limited information about the underground sewer network. We found that neglecting the sewer or simplifying its effect by reducing the precipitation rates severely overestimated the observed water depths. In contrast, simulations based on runoff removal at the stormwater inlets reproduced the observed hydrographs remarkably well after calibration of a single coefficient in the outflow relationship against the sensor data. This calibrated approach proved robust, maintaining high performance in the smaller basin across all three events. As street-level flood observations become increasingly available, the proposed methods could help identify the most accurate strategies to model pluvial flooding in diverse urban landscapes under varying levels of data availability.
{"title":"Increasing the fidelity of hyperlocal simulations of urban pluvial flooding through street flooding observations","authors":"S. Annis , M.G. Badas , G. Mascaro","doi":"10.1016/j.advwatres.2026.105223","DOIUrl":"10.1016/j.advwatres.2026.105223","url":null,"abstract":"<div><div>Urban pluvial flooding is a highly impactful natural hazard whose understanding remains limited by the scarcity of observations. Here, we demonstrated that continuous, spatially distributed, street-level flood depth measurements provide critical information to increase the fidelity of pluvial flooding simulations. We applied the LISFLOOD-FP two-dimensional, rain-on-grid hydrodynamic model to two dense urban basins of 10.9 and 0.8 km<sup>2</sup>, respectively, in New York City (NYC), where eight sensors from the FloodNet network recorded widespread flooding during three intense storms. We first provided insights into the generation of model domain and net precipitation forcings at the hyperlocal resolution of 1 m, required to quantify flood hazards at the pedestrian and vehicle scale and to support decision-making. We then focused on one event in the larger basin and assessed the performance of three modeling scenarios under the common condition of limited information about the underground sewer network. We found that neglecting the sewer or simplifying its effect by reducing the precipitation rates severely overestimated the observed water depths. In contrast, simulations based on runoff removal at the stormwater inlets reproduced the observed hydrographs remarkably well after calibration of a single coefficient in the outflow relationship against the sensor data. This calibrated approach proved robust, maintaining high performance in the smaller basin across all three events. As street-level flood observations become increasingly available, the proposed methods could help identify the most accurate strategies to model pluvial flooding in diverse urban landscapes under varying levels of data availability.</div></div>","PeriodicalId":7614,"journal":{"name":"Advances in Water Resources","volume":"209 ","pages":"Article 105223"},"PeriodicalIF":4.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146072682","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2026-01-21DOI: 10.1016/j.advwatres.2026.105217
Hamed Aghaei , Luca Colombera , Na Yan , Nigel P. Mountney , Odd Andersen , Andrea Di Giulio
This study investigates the influence of modeling choices related to the scale of reservoir heterogeneity on the predicted performance of geothermal doublets in fluvial low-enthalpy geothermal reservoirs. Fourteen geocellular grids were created to systematically analyze the impacts of numerical grid resolution, permeability upscaling methodology, and modeled scales of sedimentary architecture, using MODFLOW-2005 and MT3D-USGS to simulate groundwater flow and heat transport for well-doublet operation over a 35-year period. The results reveal complex relationships between these choices and simulated reservoir behavior: the considered factors have significant influence on injection pressures but only a modest effect on production temperatures (with variations within 2 °C after 35 years across all models), likely due, at least in part, to a relative dominance by thermal diffusion over heat advection in the considered scenarios. Simplification of geological architecture through omission of fine-scale features may augment the hydraulic impact of larger flow barriers, such as abandoned-channel mud plugs. The highest injection pressures were simulated on grids that embody sedimentary architectural elements but lack internal facies heterogeneity. The permeability upscaling method also has an effect: simulations on grids upscaled using harmonic averaging consistently yield the highest near-injector pressures, followed by those based on geometric averaging and arithmetic averaging. The dynamic behavior of grids upscaled via flow-based upscaling closely approximates that of grids upscaled using arithmetic averaging, suggesting that bulk hydraulic behavior is dominated by the connectivity of high-permeability units. The performance gap between grids following different upscaling methods decreases significantly for higher grid resolution. Simulations of geological models that incorporate increasingly detailed geological features predict cold-water plumes with slightly more complex shapes and tortuous fronts, as documented by values of plume surface-to-volume ratio. The complexity of the cold-water plume shape, as measured by the surface-to-volume ratio, is slightly higher for well doublets oriented at a high angle to the channel-belt axis, but does not increase systematically with the resolution at which fine-scale features are represented.
{"title":"Capturing scales of heterogeneity in models of fluvial geothermal reservoirs: Grid resolution, upscaling strategies, and hierarchies of sedimentary architecture","authors":"Hamed Aghaei , Luca Colombera , Na Yan , Nigel P. Mountney , Odd Andersen , Andrea Di Giulio","doi":"10.1016/j.advwatres.2026.105217","DOIUrl":"10.1016/j.advwatres.2026.105217","url":null,"abstract":"<div><div>This study investigates the influence of modeling choices related to the scale of reservoir heterogeneity on the predicted performance of geothermal doublets in fluvial low-enthalpy geothermal reservoirs. Fourteen geocellular grids were created to systematically analyze the impacts of numerical grid resolution, permeability upscaling methodology, and modeled scales of sedimentary architecture, using MODFLOW-2005 and MT3D-USGS to simulate groundwater flow and heat transport for well-doublet operation over a 35-year period. The results reveal complex relationships between these choices and simulated reservoir behavior: the considered factors have significant influence on injection pressures but only a modest effect on production temperatures (with variations within 2 °C after 35 years across all models), likely due, at least in part, to a relative dominance by thermal diffusion over heat advection in the considered scenarios. Simplification of geological architecture through omission of fine-scale features may augment the hydraulic impact of larger flow barriers, such as abandoned-channel mud plugs. The highest injection pressures were simulated on grids that embody sedimentary architectural elements but lack internal facies heterogeneity. The permeability upscaling method also has an effect: simulations on grids upscaled using harmonic averaging consistently yield the highest near-injector pressures, followed by those based on geometric averaging and arithmetic averaging. The dynamic behavior of grids upscaled via flow-based upscaling closely approximates that of grids upscaled using arithmetic averaging, suggesting that bulk hydraulic behavior is dominated by the connectivity of high-permeability units. The performance gap between grids following different upscaling methods decreases significantly for higher grid resolution. Simulations of geological models that incorporate increasingly detailed geological features predict cold-water plumes with slightly more complex shapes and tortuous fronts, as documented by values of plume surface-to-volume ratio. The complexity of the cold-water plume shape, as measured by the surface-to-volume ratio, is slightly higher for well doublets oriented at a high angle to the channel-belt axis, but does not increase systematically with the resolution at which fine-scale features are represented.</div></div>","PeriodicalId":7614,"journal":{"name":"Advances in Water Resources","volume":"209 ","pages":"Article 105217"},"PeriodicalIF":4.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146033588","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2026-01-22DOI: 10.1016/j.advwatres.2026.105221
Haokai Zhao , Rohan Bhosale , Haruko M. Wainwright
Soil moisture monitoring and forecasting are critical in hydrological modeling, agriculture, and urban stormwater management applications. In this study, an Ensemble Kalman Filter (EnKF)-based algorithm is integrated with a real-world environmental sensing network and is demonstrated for real-time estimation and near-future forecasting of soil moisture. Reference evapotranspiration (ETo) is first estimated as prior information using the FAO-56 Penman-Monteith Equation, with meteorological data measured from the sensing network, followed by the hydrological model calibration through Monte Carlo simulations. The algorithm then assimilates physics-based hydrological simulations with real-time sensor data streams. For real-time estimation, the EnKF algorithm significantly improved accuracy over the calibrated hydrological model, achieving R² values of 0.98–0.99. For near-future forecasting, it outperformed a data-driven LSTM benchmark, particularly in predicting the timing of soil moisture responses to rainfall, with R2 values ranging from 0.78 to 0.82 for 7-day predictions. In addition, by incorporating a physics-based hydrological model, the algorithm provides soil moisture estimations and forecasts across the entire vertical soil column, rather than being limited to discrete sensor depths. By bridging the gap between sensor technologies and algorithmic modeling, this study establishes a scalable, real-time soil moisture monitoring and forecasting framework that supports more efficient water use and enhances early warning capabilities for drought and flood events, contributing to climate resilience.
{"title":"A physics-guided sensor-to-model framework for real-time estimation and near-future forecasting of soil moisture","authors":"Haokai Zhao , Rohan Bhosale , Haruko M. Wainwright","doi":"10.1016/j.advwatres.2026.105221","DOIUrl":"10.1016/j.advwatres.2026.105221","url":null,"abstract":"<div><div>Soil moisture monitoring and forecasting are critical in hydrological modeling, agriculture, and urban stormwater management applications. In this study, an Ensemble Kalman Filter (EnKF)-based algorithm is integrated with a real-world environmental sensing network and is demonstrated for real-time estimation and near-future forecasting of soil moisture. Reference evapotranspiration (ETo) is first estimated as prior information using the FAO-56 Penman-Monteith Equation, with meteorological data measured from the sensing network, followed by the hydrological model calibration through Monte Carlo simulations. The algorithm then assimilates physics-based hydrological simulations with real-time sensor data streams. For real-time estimation, the EnKF algorithm significantly improved accuracy over the calibrated hydrological model, achieving R² values of 0.98–0.99. For near-future forecasting, it outperformed a data-driven LSTM benchmark, particularly in predicting the timing of soil moisture responses to rainfall, with R<sup>2</sup> values ranging from 0.78 to 0.82 for 7-day predictions. In addition, by incorporating a physics-based hydrological model, the algorithm provides soil moisture estimations and forecasts across the entire vertical soil column, rather than being limited to discrete sensor depths. By bridging the gap between sensor technologies and algorithmic modeling, this study establishes a scalable, real-time soil moisture monitoring and forecasting framework that supports more efficient water use and enhances early warning capabilities for drought and flood events, contributing to climate resilience.</div></div>","PeriodicalId":7614,"journal":{"name":"Advances in Water Resources","volume":"209 ","pages":"Article 105221"},"PeriodicalIF":4.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146033589","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2026-02-06DOI: 10.1016/j.advwatres.2026.105235
Sree Rama Teja Tripuraneni , Daniel M. Tartakovsky, Hamdi A. Tchelepi
Modeling subsurface flow and transport is notoriously challenging due to an inadequate understanding of site characteristics. Especially when the fluid in our model is compressible, we should have a reliable estimate of spatiotemporal changes not only in the pressure in a specific scenario but also in the probability of the pressure evolution, as the hydraulic conductivity is an uncertain parameter. As a result, samples of the conductivity maps are generated on the basis of field scale studies and Monte Carlo simulations are often utilized to characterize the probability distribution of pressure. In this work, we develop method of distributions (CDF equation) for a transient problem as an alternative uncertainty quantification procedure. The CDF equation derived here is not in closed form, so we also formulate a strategy to solve the Moment equations, obtain mean and variance of pressure field and then use them as closure. We observe that the CDF result from the method of distributions yields an accurate estimate with a deviation less than 5% from a convergent MCS estimate when we apply to both statistically homogeneous and heterogeneous hydraulic conductivity in our examples. In addition, it is about 10 to 20 times faster than the MCS counterpart, depending on the type of grid we use to solve the moment equations.
{"title":"Method of distributions for transient flow in porous media with uncertain properties","authors":"Sree Rama Teja Tripuraneni , Daniel M. Tartakovsky, Hamdi A. Tchelepi","doi":"10.1016/j.advwatres.2026.105235","DOIUrl":"10.1016/j.advwatres.2026.105235","url":null,"abstract":"<div><div>Modeling subsurface flow and transport is notoriously challenging due to an inadequate understanding of site characteristics. Especially when the fluid in our model is compressible, we should have a reliable estimate of spatiotemporal changes not only in the pressure in a specific scenario but also in the probability of the pressure evolution, as the hydraulic conductivity is an uncertain parameter. As a result, samples of the conductivity maps are generated on the basis of field scale studies and Monte Carlo simulations are often utilized to characterize the probability distribution of pressure. In this work, we develop method of distributions (CDF equation) for a transient problem as an alternative uncertainty quantification procedure. The CDF equation derived here is not in closed form, so we also formulate a strategy to solve the Moment equations, obtain mean and variance of pressure field and then use them as closure. We observe that the CDF result from the method of distributions yields an accurate estimate with a deviation less than 5% from a convergent MCS estimate when we apply to both statistically homogeneous and heterogeneous hydraulic conductivity in our examples. In addition, it is about 10 to 20 times faster than the MCS counterpart, depending on the type of grid we use to solve the moment equations.</div></div>","PeriodicalId":7614,"journal":{"name":"Advances in Water Resources","volume":"209 ","pages":"Article 105235"},"PeriodicalIF":4.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146134972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2026-01-19DOI: 10.1016/j.advwatres.2026.105220
Zhao Guo, FuTian Ren, DanBing Mei, Fan Liu, ZengHui Li, XiaoWei Lu, Lei Huang
Accurate inversion of spatially distributed hydraulic conductivity (K) under sparse observations and unstructured meshes is essential for realistic groundwater simulation and effective resource management. This study presents a physics-informed deep learning framework that integrates a Multi-Resolution Radial Basis Network (MRRBN) and a Topology-Adaptive Graph Attention Network (TAGAT) to jointly reconstruct domain-wide head fields and invert the K field. The MRRBN employs multi-resolution spatial interpolation and data-driven weighting to recover continuous head fields from limited measurements. The TAGAT incorporates graph topology and physics-informed flow characteristics derived from Darcy’s law, including instantaneous fluxes and local source-sink dynamics, to capture short- and long-range dependencies across unstructured meshes. Evaluated on synthetic aquifer scenarios featuring heterogeneous conductivity, variable boundary conditions, and stochastic rainfall, the proposed model achieved the following metrics (training, validation): R2 (0.89, 0.83), RMSE (0.683, 0.844), MAE (0.530, 0.642), and maintained robust accuracy under realistic levels of measurement noise. Residuals concentrate along conductivity-transition bands and mid-gradient zones where the sensitivity of head to K is low. We benchmark against graph-network baselines, treating multi-order topology and physics-informed features as independent factors, and we control model size by matching parameter counts under fixed data and training protocols. Results indicate a physically consistent, mesh-native solution for conductivity inversion with practical implications for site-scale groundwater analysis.
{"title":"Topology-Adaptive Graph Attention Networks coupled with radial basis functions: A novel framework for hydraulic conductivity inversion in unstructured meshes","authors":"Zhao Guo, FuTian Ren, DanBing Mei, Fan Liu, ZengHui Li, XiaoWei Lu, Lei Huang","doi":"10.1016/j.advwatres.2026.105220","DOIUrl":"10.1016/j.advwatres.2026.105220","url":null,"abstract":"<div><div>Accurate inversion of spatially distributed hydraulic conductivity (K) under sparse observations and unstructured meshes is essential for realistic groundwater simulation and effective resource management. This study presents a physics-informed deep learning framework that integrates a Multi-Resolution Radial Basis Network (MRRBN) and a Topology-Adaptive Graph Attention Network (TAGAT) to jointly reconstruct domain-wide head fields and invert the K field. The MRRBN employs multi-resolution spatial interpolation and data-driven weighting to recover continuous head fields from limited measurements. The TAGAT incorporates graph topology and physics-informed flow characteristics derived from Darcy’s law, including instantaneous fluxes and local source-sink dynamics, to capture short- and long-range dependencies across unstructured meshes. Evaluated on synthetic aquifer scenarios featuring heterogeneous conductivity, variable boundary conditions, and stochastic rainfall, the proposed model achieved the following metrics (training, validation): R<sup>2</sup> (0.89, 0.83), RMSE (0.683, 0.844), MAE (0.530, 0.642), and maintained robust accuracy under realistic levels of measurement noise. Residuals concentrate along conductivity-transition bands and mid-gradient zones where the sensitivity of head to K is low. We benchmark against graph-network baselines, treating multi-order topology and physics-informed features as independent factors, and we control model size by matching parameter counts under fixed data and training protocols. Results indicate a physically consistent, mesh-native solution for conductivity inversion with practical implications for site-scale groundwater analysis.</div></div>","PeriodicalId":7614,"journal":{"name":"Advances in Water Resources","volume":"209 ","pages":"Article 105220"},"PeriodicalIF":4.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146001384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2026-01-28DOI: 10.1016/j.advwatres.2026.105224
Yunhui Wang , Peng Wu , Dan Li , Haiyuan Yao , Lei Huang , Yanghui Li
Accurate permeability prediction in hydrate-bearing sediments (HBS) is crucial for efficient hydrate exploitation and production control. However, hydrate dissociation processes exhibit significant heterogeneity and discontinuity. Traditional methods, which phenomenologically study seepage behavior by only considering saturation and effective pore changes, often fail to effectively describe the coupled influence of complex pore structure evolution and permeability under hydrate phase transition and in-situ stress. This study utilized an X-ray computed tomography triaxial system to conduct micro-visualization tests of HBS depressurization and thermal stimulation dissociation under constant axial load and identical supercooling conditions. We found that thermal stimulation significantly accelerated the dissociation rate by approximately 75% compared to depressurization. Quantitative digital volume correlation analysis revealed thermal stimulation led to more intense, randomly distributed pore-scale damage, with the maximum vertical displacement increment being 20% higher than depressurization. The complex pore structure change profoundly impacts fluid transport and production potential. Therefore, from the perspective of pore fractal structure evolution, we proposed a permeability model based on fractal parameter and established an upscaling framework for accurately predicting heterogeneous core permeability. This framework achieved a 33.93% improvement in root mean square error compared to homogeneous assumptions. Leveraging its enhanced accuracy, this study provides critical guidance for optimizing oil and gas exploitation, improving recovery efficiency, and reducing risks in complex geological environments.
{"title":"Pore morphology and permeability evolution of hydrate-bearing sediments during dissociation process","authors":"Yunhui Wang , Peng Wu , Dan Li , Haiyuan Yao , Lei Huang , Yanghui Li","doi":"10.1016/j.advwatres.2026.105224","DOIUrl":"10.1016/j.advwatres.2026.105224","url":null,"abstract":"<div><div>Accurate permeability prediction in hydrate-bearing sediments (HBS) is crucial for efficient hydrate exploitation and production control. However, hydrate dissociation processes exhibit significant heterogeneity and discontinuity. Traditional methods, which phenomenologically study seepage behavior by only considering saturation and effective pore changes, often fail to effectively describe the coupled influence of complex pore structure evolution and permeability under hydrate phase transition and in-situ stress. This study utilized an X-ray computed tomography triaxial system to conduct micro-visualization tests of HBS depressurization and thermal stimulation dissociation under constant axial load and identical supercooling conditions. We found that thermal stimulation significantly accelerated the dissociation rate by approximately 75% compared to depressurization. Quantitative digital volume correlation analysis revealed thermal stimulation led to more intense, randomly distributed pore-scale damage, with the maximum vertical displacement increment being 20% higher than depressurization. The complex pore structure change profoundly impacts fluid transport and production potential. Therefore, from the perspective of pore fractal structure evolution, we proposed a permeability model based on fractal parameter and established an upscaling framework for accurately predicting heterogeneous core permeability. This framework achieved a 33.93% improvement in root mean square error compared to homogeneous assumptions. Leveraging its enhanced accuracy, this study provides critical guidance for optimizing oil and gas exploitation, improving recovery efficiency, and reducing risks in complex geological environments.</div></div>","PeriodicalId":7614,"journal":{"name":"Advances in Water Resources","volume":"209 ","pages":"Article 105224"},"PeriodicalIF":4.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146072683","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-01Epub Date: 2026-01-21DOI: 10.1016/j.advwatres.2026.105216
Pierre Ailliot , Carlo Gaetan , Philippe Naveau
Modeling the probability distribution of rainfall intensities at different aggregation scales, say from sub-hourly to weekly, has always played a key role in most hydrological risk analysis, in particular in the computation of Intensity-Duration-Frequency (IDF) curves. Since any aggregation procedure involves accumulating rainfall over a prescribed time window, it naturally induces simple mathematical constraints related to summation. In particular, return levels inferred from a statistical model should be ordered across time scales, reflecting for example the fact that observed daily accumulations necessarily exceed those at sub-daily scales. From a statistical modeling perspective, each aggregation step combines information from shorter time scales without introducing additional data. Consequently, the number of model parameters should remain limited. Still, parsimonious aggregation models that describe the full distribution of rainfall intensities are sparse in the hydrological literature. In particular, most studies focus on extremes, e.g. by taking seasonal block maxima at different aggregation scales.
In this study, we propose a statistical framework that allows to model all rainfall intensities (low, medium and large) at different aggregation scales, while being parsimonious. To reach this goal, we use the extended generalized Pareto distribution (EGPD), which complies with extreme value theory for both low and high extremes and is flexible enough to capture the bulk of the distribution. We show a general result that explains how EGPD random variables behave under different types of aggregation procedures. Direct likelihood inference is difficult in our setting. However, by linking the EGPD class to Poisson compound sums, we can use the Panjer algorithm to quickly and efficiently evaluate the composite likelihood of our proposed model. As a result, return levels can be obtained for any return period, particularly those below the annual and seasonal scales. In addition, our approach insures that return levels do not cross with aggregation.
To demonstrate the applicability of our method, we analyze sub-hourly time series from six gauging stations in France that have different climatological features. For each station, we only need a total of eight parameters to capture aggregation scales from six minutes to three days. IDF curves above and below the annual scale are provided.
{"title":"A parsimonious tail compliant multiscale statistical model for aggregated rainfall","authors":"Pierre Ailliot , Carlo Gaetan , Philippe Naveau","doi":"10.1016/j.advwatres.2026.105216","DOIUrl":"10.1016/j.advwatres.2026.105216","url":null,"abstract":"<div><div>Modeling the probability distribution of rainfall intensities at different aggregation scales, say from sub-hourly to weekly, has always played a key role in most hydrological risk analysis, in particular in the computation of Intensity-Duration-Frequency (IDF) curves. Since any aggregation procedure involves accumulating rainfall over a prescribed time window, it naturally induces simple mathematical constraints related to summation. In particular, return levels inferred from a statistical model should be ordered across time scales, reflecting for example the fact that observed daily accumulations necessarily exceed those at sub-daily scales. From a statistical modeling perspective, each aggregation step combines information from shorter time scales without introducing additional data. Consequently, the number of model parameters should remain limited. Still, parsimonious aggregation models that describe the full distribution of rainfall intensities are sparse in the hydrological literature. In particular, most studies focus on extremes, e.g. by taking seasonal block maxima at different aggregation scales.</div><div>In this study, we propose a statistical framework that allows to model all rainfall intensities (low, medium and large) at different aggregation scales, while being parsimonious. To reach this goal, we use the extended generalized Pareto distribution (EGPD), which complies with extreme value theory for both low and high extremes and is flexible enough to capture the bulk of the distribution. We show a general result that explains how EGPD random variables behave under different types of aggregation procedures. Direct likelihood inference is difficult in our setting. However, by linking the EGPD class to Poisson compound sums, we can use the Panjer algorithm to quickly and efficiently evaluate the composite likelihood of our proposed model. As a result, return levels can be obtained for any return period, particularly those below the annual and seasonal scales. In addition, our approach insures that return levels do not cross with aggregation.</div><div>To demonstrate the applicability of our method, we analyze sub-hourly time series from six gauging stations in France that have different climatological features. For each station, we only need a total of eight parameters to capture aggregation scales from six minutes to three days. IDF curves above and below the annual scale are provided.</div></div>","PeriodicalId":7614,"journal":{"name":"Advances in Water Resources","volume":"208 ","pages":"Article 105216"},"PeriodicalIF":4.2,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146014996","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-01Epub Date: 2026-01-16DOI: 10.1016/j.advwatres.2026.105218
Yihang Xiao , Zhenjiang You , Yongming He , Shuangshuang Sun , Lei Wang
Boundary conditions play a critical role in regulating the mechanical factors and flow patterns during spontaneous imbibition. While numerous studies have examined effects of boundary conditions using cylindrical cores, the anisotropic flow behaviors induced by geometric asymmetry and the limited boundary condition types in such geometries pose challenges for quantitative analysis. Moreover, prior research has primarily focused on static boundary conditions, neglecting the impact of time-varying scenarios. To address these gaps, this study employed four cubic rock samples to investigate imbibition process of gas-water systems under 12 static and 4 time-varying boundary conditions. The work systematically explores imbibition characteristics, gas drainage mechanisms, and the combined effects of boundary conditions and permeability. The results show that imbibition process under static boundary conditions exhibits distinct initial, transition, and late stages, whereas only the initial stage is observed under time-varying conditions. However, in low-permeability rock samples, a high water injection rate results in decreasing imbibition velocity during the end-stage imbibition, due to pronounced counter-current flow. Under static boundary conditions, gas is rapidly displaced from the core despite capillary back pressure. In contrast, under time-varying conditions, gas drainage remains unaffected by capillary back pressure, because gas expulsion occurs primarily through rock surfaces exposed to air. In addition, the number of open boundaries influences imbibition recovery and velocity, following different nonlinear trends. The transition stage contributes most significantly to the total imbibition recovery, yet the relative contributions of different imbibition stages remain independent of the number of open boundaries. Furthermore, increasing water injection rate enhances imbibition velocity under time-varying boundary conditions, but this effect becomes less pronounced once the injection rate exceeds a critical threshold. Interestingly, imbibition recoveries remain consistent across all time-varying and static boundary conditions, owing to strong hydrophilic interactions and efficient gas displacement. Additionally, imbibition capacity is significantly improved when more open boundaries or higher water injection rates are coupled with greater permeability. These observations provide new insights into the distinct imbibition mechanisms under complex boundary conditions.
{"title":"Impacts of complex boundary conditions on spontaneous imbibition in gas-water systems","authors":"Yihang Xiao , Zhenjiang You , Yongming He , Shuangshuang Sun , Lei Wang","doi":"10.1016/j.advwatres.2026.105218","DOIUrl":"10.1016/j.advwatres.2026.105218","url":null,"abstract":"<div><div>Boundary conditions play a critical role in regulating the mechanical factors and flow patterns during spontaneous imbibition. While numerous studies have examined effects of boundary conditions using cylindrical cores, the anisotropic flow behaviors induced by geometric asymmetry and the limited boundary condition types in such geometries pose challenges for quantitative analysis. Moreover, prior research has primarily focused on static boundary conditions, neglecting the impact of time-varying scenarios. To address these gaps, this study employed four cubic rock samples to investigate imbibition process of gas-water systems under 12 static and 4 time-varying boundary conditions. The work systematically explores imbibition characteristics, gas drainage mechanisms, and the combined effects of boundary conditions and permeability. The results show that imbibition process under static boundary conditions exhibits distinct initial, transition, and late stages, whereas only the initial stage is observed under time-varying conditions. However, in low-permeability rock samples, a high water injection rate results in decreasing imbibition velocity during the end-stage imbibition, due to pronounced counter-current flow. Under static boundary conditions, gas is rapidly displaced from the core despite capillary back pressure. In contrast, under time-varying conditions, gas drainage remains unaffected by capillary back pressure, because gas expulsion occurs primarily through rock surfaces exposed to air. In addition, the number of open boundaries influences imbibition recovery and velocity, following different nonlinear trends. The transition stage contributes most significantly to the total imbibition recovery, yet the relative contributions of different imbibition stages remain independent of the number of open boundaries. Furthermore, increasing water injection rate enhances imbibition velocity under time-varying boundary conditions, but this effect becomes less pronounced once the injection rate exceeds a critical threshold. Interestingly, imbibition recoveries remain consistent across all time-varying and static boundary conditions, owing to strong hydrophilic interactions and efficient gas displacement. Additionally, imbibition capacity is significantly improved when more open boundaries or higher water injection rates are coupled with greater permeability. These observations provide new insights into the distinct imbibition mechanisms under complex boundary conditions.</div></div>","PeriodicalId":7614,"journal":{"name":"Advances in Water Resources","volume":"208 ","pages":"Article 105218"},"PeriodicalIF":4.2,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145995706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-01Epub Date: 2026-01-17DOI: 10.1016/j.advwatres.2026.105219
Yi-Peng Zhang , Barret L. Kurylyk , Anner Paldor
Coastal aquifers provide a vital connection between land and ocean, where the dynamics of groundwater flow and solute transport are influenced by confounding effects from hydrogeologic, morphologic, climatic, and oceanic forcings. Most previous studies of coastal and subsea aquifers have focused on aquifers with continuous structures, with few addressing submarine faults that can disrupt this continuity and play a controlling role in groundwater flow, salinity and age distributions. We investigate the understudied influence of submarine faults by simulating a generalized coastal aquifer-aquitard system with a fault cutting through the system, with simulations accounting for realistic sea-level rise over paleohydrogeologic timescales. Results show that faults reduce the extent of offshore freshened groundwater (OFG) regardless of their location. Faults proximal to the coastline serve as pathways for freshwater discharge, accounting for up to 18.1% of total submarine groundwater discharge (SGD), and transport groundwater that is 7 times older than the surrounding SGD. Conversely, faults located farther offshore act as conduits for downward seawater infiltration, rejuvenating deep aquifers by a negative peak of 2000 years with saline water. The two contrasting processes may regulate the chemical loads of groundwater through the seafloor. The dip of the aquitard has little impact on OFG extent but enhances the flux of groundwater discharge through the fault to the sea. The control of faults over groundwater flow peaks when the fault is oriented vertically. The findings suggest that special attention should be paid to submarine faults, which can strongly influence fresh groundwater resources and biogeochemical reactions in coastal/marine areas.
{"title":"Submarine faults strongly impact age and salinity distributions in offshore freshened groundwater systems","authors":"Yi-Peng Zhang , Barret L. Kurylyk , Anner Paldor","doi":"10.1016/j.advwatres.2026.105219","DOIUrl":"10.1016/j.advwatres.2026.105219","url":null,"abstract":"<div><div>Coastal aquifers provide a vital connection between land and ocean, where the dynamics of groundwater flow and solute transport are influenced by confounding effects from hydrogeologic, morphologic, climatic, and oceanic forcings. Most previous studies of coastal and subsea aquifers have focused on aquifers with continuous structures, with few addressing submarine faults that can disrupt this continuity and play a controlling role in groundwater flow, salinity and age distributions. We investigate the understudied influence of submarine faults by simulating a generalized coastal aquifer-aquitard system with a fault cutting through the system, with simulations accounting for realistic sea-level rise over paleohydrogeologic timescales. Results show that faults reduce the extent of offshore freshened groundwater (OFG) regardless of their location. Faults proximal to the coastline serve as pathways for freshwater discharge, accounting for up to 18.1% of total submarine groundwater discharge (SGD), and transport groundwater that is 7 times older than the surrounding SGD. Conversely, faults located farther offshore act as conduits for downward seawater infiltration, rejuvenating deep aquifers by a negative peak of 2000 years with saline water. The two contrasting processes may regulate the chemical loads of groundwater through the seafloor. The dip of the aquitard has little impact on OFG extent but enhances the flux of groundwater discharge through the fault to the sea. The control of faults over groundwater flow peaks when the fault is oriented vertically. The findings suggest that special attention should be paid to submarine faults, which can strongly influence fresh groundwater resources and biogeochemical reactions in coastal/marine areas.</div></div>","PeriodicalId":7614,"journal":{"name":"Advances in Water Resources","volume":"208 ","pages":"Article 105219"},"PeriodicalIF":4.2,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145995707","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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