Search Results (223)

With the increasing exploration and development of deep (>4500 m) hydrocarbon resources, fault-controlled reservoirs have become important sweet-spot targets in deeply buried tight rocks. However, it remains challenging to decipher the coupled relationships among deformation, fluid flow, diagenesis, and reservoir evolution within fault damage zones. In this review, we synthesize recent advances, including contributions to this Special Issue, on deformation, diagenesis, and reservoir development within fault damage zones in sedimentary basins. Fault-zone architecture commonly comprises a narrow fault core and a wider damage zone, with fault cores supported by particles, matrix, or cement, and damage zones characterized by outward-decreasing deformation intensity and fracture network complexity. Although fracture intensity, porosity, and permeability commonly follow a power-law decrease with increasing distance from the fault core, these parameters are highly scattered because they are jointly controlled by complex structural and diagenetic overprinting. Non-Andersonian fault-tip propagation, fault interaction, linkage, and reactivation play key roles in the development of wide and heterogeneous fracture zones. During progressive burial, mechanical compaction and cementation generally reduce primary porosity, whereas dissolution may generate or enhance secondary pore systems. Hydrothermal dissolution can locally improve reservoir quality, whereas mineral precipitation commonly occludes pores and fractures and reduces permeability. Except for the high-energy microfacies, the coupling between fracturing and contemporaneous, burial-related, or supergene dissolution is critical for the formation and preservation of secondary reservoirs. Integrated faulting period analysis and U-Pb dating of carbonate cements within fractures provide an effective approach for reconstructing the timing of fracturing, fluid flow, and diagenetic modification. In sedimentary basins, heterogeneous fractured reservoirs are unevenly distributed along fault damage zones. Their formation is controlled by the complex coupling of lithology, structural deformation, fluid flow, and diagenesis. Therefore, the key scientific challenge is to quantitatively characterize the spatio-temporal evolution and coupling mechanisms of deformation, diagenesis and fluid flow control on reservoir properties within fault damage zones. Ultimately, this review provides a novel, time-resolved framework for predicting deep sweet-spot reservoirs, shifting the paradigm from purely structural description to quantitative structural–diagenetic modeling. Full article

Heap leaching efficiency is constrained by the non-uniform seepage of the leaching solution (such as sulphuric acid), where preferential flow and localized plugging lead to low leaching rates, prolonged cycles, and high acid consumption. Seepage behavior is fundamentally governed by pore structure, which evolves continuously during leaching through chemical dissolution and physical plugging, and in turn feeds back to affect reactive transport by altering seepage pathways. Taking low-grade copper oxide ore (0.58%) as the research object, this study systematically investigates the chemical–physical coupling mechanisms of pore structure evolution and the corresponding regulation strategies through column leaching experiments, shrinking-core kinetics analysis, migration-plugging analysis, and COMSOL multi-physics coupling simulation. The results indicate that copper leaching is jointly controlled by chemical reaction and diffusion, with the apparent rate constant following a power-law relationship with acid concentration (reaction order n = 0.65), demonstrating significantly diminishing marginal gains. Physical plugging is identified as a critical factor in the sharp decline of permeability, with the hydraulic conductivity of the 0.2 mm particle size group decreasing by 86.58%, far exceeding the 37.80% reduction observed in the 0.05 mm group. On this basis, chemical–physical coupling mechanism analysis reveals the competitive control of four mechanisms over pore evolution: dissolution-induced pore enlargement, precipitation-induced pore shrinkage, plugging-induced pore shrinkage, and collapse-induced pore shrinkage. A COMSOL-based multi-physics coupling model integrating seepage, reaction, migration, and mechanics is constructed to predict porosity, permeability, and leaching rate during the leaching process, with model errors below 10%. The temporal contribution rates of the four mechanisms reveal a three-stage evolution pattern: a dissolution-dominated stage in the early period, a multi-mechanism competitive stage in the middle period, and a precipitation-plugging synergistic densification stage (accounting for >90% in total) in the later period. Accordingly, a phased spray regulation strategy is proposed, achieving a leaching rate exceeding 65% under uniform flow velocity conditions. This study provides a theoretical basis and numerical tools for enhancing the leaching efficiency of low-grade copper ores. Full article

Before Cyclone Senyar made landfall on Sumatra in November 2025, it drew moisture from across the South China Sea, the Gulf of Thailand, and the Indian Ocean. The substantial damage its heavy rainfall caused on the NE and W coasts of Sumatra urges us to rethink the relationships between climate, forests, hydrology, land use, human presence, and vulnerability. Cyclones will recur, but flood damage does not have to be repeated. The simple narrative that “deforestation causes floods” is not adequate for guiding a “building back better” strategy. To account for the space-time pattern of Senyar effects with its multiple landfalls, we reviewed key concepts and framing of the links between ocean temperature, atmospheric moisture transport, rainfall extremes, saturation of existing buffers (“sponges”), river flow, and flooding. We hypothesize how atmospheric roughness slowing down rivers in the sky can induce congestion and precipitation. Surface infiltration and water retention in the soil profile matter. Mid- and downstream flow delays due to sponge effects depend on land cover beyond what a simple forest–non-forest terminology can represent. Rather than indiscriminate tree planting, adaptation efforts to avoid future disasters should balance reductions in human exposure (effective land use planning) and efforts to reduce hazards by restoring and managing vegetation and drainage systems. Full article

This study aims to characterize the seasonal variability and optical properties of aerosols and to investigate their potential sources, transport pathways, and radiative impacts over a rural site in Southeast India. Ground–based MICROTOPS–II Sunphotometer observations during April 2021–December 2023 were integrated with trajectory–based source analysis and OPAC–SBDART radiative–transfer simulations to examine the links between aerosol characteristics, meteorological conditions, source regions, and radiative effects. The annual mean aerosol optical depth at 500 nm (AOD₅₀₀) was found to be 0.56 ± 0.22, peaking during pre–monsoon (0.66 ± 0.19) and winter (0.64 ± 0.23), and lowering during the rainy monsoon (0.49 ± 0.21). Enhanced aerosol loading during the dry seasons was associated with local emissions and long–range continental transport, whereas monsoon conditions favored marine influence, atmospheric ventilation and wet scavenging, as supported by trajectory analyses using potential source contribution function (PSCF) and concentration weighted trajectory (CWT) models. Higher Ångström exponent (AE) values during winter and pre–monsoon (1.30 ± 0.24) indicated dominance of fine–mode continental aerosols, while the lower monsoon values (0.83 ± 0.37) reflected increased contribution of coarse particles. Negative values of spectral curvature further confirmed fine–mode dominance during dry seasons. The estimated precipitable water vapor increased markedly from winter (2.00 ± 0.37 cm) to monsoon (4.35 ± 0.35 cm), likely influencing aerosol optical properties through hygroscopic growth. Meteorological parameters significantly modulated aerosol loading and size distribution across seasons. AOD–AE relationships revealed predominance of fine anthropogenic aerosols in all seasons except monsoon, while aerosol classification indicated substantial fine–mode contributions under turbid atmospheric conditions. OPAC–SBDART simulations estimated significant aerosol–induced surface cooling (−41 to −42 W m⁻²) and atmospheric warming (38–41 W m⁻²) under high aerosol loading conditions, leading to atmospheric heating rates of 1.1–1.2 K day⁻¹. However, lower aerosol loading in monsoon reduced heating rates to 0.3–0.4 K day⁻¹. Current findings highlight the critical role of monsoon flow and meteorological dynamics in regulating aerosol characteristics and regional radiative forcing over Southeast India. 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

The 7075-T6 aluminum alloy exhibits excellent specific strength due to the presence of precipitated η′ phase, but its surface mechanical performance under demanding conditions is often limited. In this study, a horizontal cylindrical magnetron sputtering system was used to deposit TiN coatings on the surface of 7075-T6 aluminum alloy to enhance its surface mechanical properties and structural performance. The effects of deposition temperature, substrate bias voltage, and N₂/Ar flow ratio on the microstructure, surface morphology, phase composition, hardness, and residual stress of the coatings were systematically investigated. The results showed that at 80 °C, enhanced lateral atomic diffusion promoted the transformation of the coating growth mode from coarse columnar crystals to dense quasi-layered structures. The surface roughness decreased from 0.193 μm at room temperature to 0.077 μm, the (111) preferred orientation significantly increased, the hardness reached 383 HV, and the compressive stress was −2.8 GPa. However, when the temperature was raised to 120 °C, grain coarsening and TiN/7075Al interface thermal mismatch stress dominated, and the hardness decreased by approximately 19.3%. At −80 V bias, the atomic impact effect produced by ion bombardment made the coating densified optimally, with the lowest surface roughness of 0.068 μm, a hardness of 377 HV, and a compressive stress of −3.1 GPa; at −150 V, excessive bombardment led to severe re-sputtering and lattice distortion, resulting in a compressive stress of −6.8 GPa and a hardness of 351 HV. When N₂/Ar = 10/25, the reaction sputtering kinetics and chemical thermodynamic conditions reached the optimal balance, achieving the highest diffraction peak signal-to-noise ratio and the narrowest full width at half maximum. These results reveal the temperature-dependent competitive relationship between thermally activated coating densification and thermal mismatch-induced structural degradation, providing insights into the optimization of TiN coating deposition parameters on aluminum alloys. Full article

Streamflow estimation at ungauged sections is essential for flood warning, reservoir operation, water allocation, and basin management. Conventional regionalization approaches typically require the construction, calibration, and parameter transfer of conceptual or process-based hydrological models, resulting in high application costs when data are scarce, gauge networks are frequently adjusted, or management sections do not coincide with existing gauging stations. In recent years, regional Long Short-Term Memory (LSTM) networks have provided a data-driven alternative for ungauged streamflow estimation. However, existing studies have focused mainly on spatial generalization across independent catchments, with limited attention to hydrological information transfer among sections with different upstream and downstream relationships within the same nested basin. This study used five nested hydrological stations in the Fujiang River Basin to develop a Hydrological-Efficiency-Guided Long Short-Term Memory framework (HEG-LSTM) and compared it with a baseline LSTM. The model incorporated local meteorological forcing, antecedent precipitation, static basin attributes, and scenario-permitted donor-station discharge as inputs, and leave-one-station-out validation was adopted to assess cross-section applicability. To investigate the effects of different upstream and downstream relationships on streamflow estimation, three gauge-network scenarios were designed: S1 estimated downstream streamflow using upstream stations; S2 was downstream-to-upstream synchronous estimation; and S3 jointly estimated streamflow at an intermediate ungauged section using upstream and downstream stations. HEG-LSTM achieved a mean Nash–Sutcliffe efficiency (NSE) of 0.703, exceeding the 0.603 obtained by the baseline LSTM. The mean NSE values of HEG-LSTM under S1, S2, and S3 were 0.692, 0.695, and 0.730, respectively, with the best performance obtained under S3. Compared with the baseline LSTM, HEG-LSTM increased the coefficient of determination for high flow from 0.617 to 0.737 and that for annual peak flow from 0.731 to 0.770, whereas improvement in low flow correlation remained limited. Shapley Additive Explanations (SHAP) showed that donor-station discharge, drainage area, elevation, slope, and antecedent precipitation jointly influenced cross-section transferability. The proposed HEG-LSTM framework provides a methodological reference for streamflow estimation, historical streamflow estimation, and gauge-network optimization at ungauged sections in nested basins. Full article

Short-term multivariate forecasting of hydrological variables remains challenging because river systems exhibit nonlinear and time-dependent dynamics, complex relationships among water level, flow, and precipitation, and uncertainty arising from measurement errors and external disturbances. Although neural network models can learn nonlinear relationships among hydrological variables, their predictive performance often deteriorates in the presence of noise. Moreover, existing approaches rarely integrate the learning of long-term temporal dependencies and cross-variable relationships with a data assimilation mechanism capable of recursively updating state estimates and reducing forecast uncertainty. This limitation reveals the need for a robust forecasting framework that combines both capabilities. Therefore, this study aimed to develop and evaluate a hybrid Long Short-Term Memory–Ensemble Kalman Filter (LSTM–EnKF) model for short-term multivariate water-level forecasting under noisy conditions. The proposed framework extends a previously developed NARX–EnKF approach by replacing the NARX network with an LSTM architecture capable of learning nonlinear temporal patterns and relationships among water level, flow, and precipitation. The model was implemented using data from two hydrological stations located along the Atrato River in Colombia and configured to generate water-level forecasts with a two-day prediction horizon. The LSTM network generated the initial forecasts, whereas the EnKF assimilated the available observations to recursively update the estimated states and reduce forecast uncertainty. Model robustness was examined by introducing Gaussian white noise with variance levels of 0.001, 0.05, 0.10, and 0.20 to represent measurement uncertainty and external disturbances. Performance was evaluated using the root mean square error (RMSE), mean absolute error (MAE), and Nash–Sutcliffe efficiency (NSE). Across all evaluated noise levels, the LSTM–EnKF model outperformed the standalone LSTM model. Its total RMSE ranged from 0.1009 to 0.1929 m, compared with 0.1740 to 0.2356 m for the standalone LSTM, representing reductions of approximately 18.1–42%. The hybrid model achieved NSE values ranging from 0.9760 to 0.9992, whereas the standalone LSTM produced values between 0.9200 and 0.9776. Furthermore, the LSTM–EnKF reduced the MAE by approximately 51.9–56.2% across both outputs. These results indicate that integrating LSTM-based temporal learning with EnKF-based data assimilation improves short-term forecasting accuracy and robustness under noisy conditions. The developed framework provides a promising tool for supporting flood early-warning systems, flood-risk management, and the protection of riverine communities. Full article

Supercritical CO₂ injection can mitigate depletion-induced deterioration of shale oil, but the relationship between laboratory-scale fluid-property changes and field-scale recovery remains insufficiently understood. This study integrates time-lapse produced-oil characterization, high-pressure PVT experiments, whole-hydrocarbon gas chromatography, and compositional reservoir simulation for the Mabei shale oil reservoir. From October 2023 to October 2025, the viscosity of dehydrated and degassed produced oil at 80 °C increased from 20.93 to 56.8 mPa·s, accompanied by depletion of light hydrocarbons and enrichment of heavy components, indicating progressive compositional deterioration during depletion. At 106.75 °C and 65.07 MPa, increasing the added CO₂/oil molar ratio from 0 to 80% reduced live-oil viscosity from 9.7841 to 3.8470 mPa·s and density from 0.8326 to 0.7897 g/cm³. Most viscosity, density, and oil-phase compositional changes occurred within the first 6 h in the closed, continuously stirred PVT cell. CO₂ contact preferentially transferred C3–C7 hydrocarbons out of the analyzed oil-rich phase, resulting in relative enrichment of C15–C37 components in the residual oil. The history-matched compositional model showed that CO₂ improved reservoir pressure maintenance and expanded low-viscosity regions primarily along fracture-connected flow paths, although the incremental response became limited between the 20 and 25% cases. Regional compositional analysis further demonstrated that strongly CO₂-contacted residual oil became heavier, whereas the produced oil was enriched in mobilized light and intermediate hydrocarbons. These results establish a consistent laboratory-to-field interpretation of CO₂-induced compositional redistribution and provide a basis for optimizing CO₂-assisted development in deeply buried shale oil reservoirs. CO₂-induced asphaltene precipitation/deposition and the associated permeability impairment were not measured or represented in the numerical model. Therefore, the reported recovery response reflects CO₂–oil property and transport effects in the absence of solid-phase formation damage. Full article

In order to clarify the effects of the volcanic activity on hydrological, thermal and chemical features of a crater lake, Lake Katanuma, Japan, temperature and electrical conductivity at 25 °C (EC25) of lake water were monitored at two maximum-depth points in 2023−2025. Under closed condition of the lake without river outflow, the lake is characterized by a high acidity of pH = 2 on average and the existence of the surrounding geothermal area. A seasonal variation in the thermal and chemical features of the lake was shown by sporadic vertical profiling (0.1 m pitch) of temperature, EC25 and dissolved oxygen (DO) at the two points. The groundwater flow system around the lake was specified by quantifying the groundwater inflow G_in and groundwater outflow G_out in the lake from the estimate of hydrological and chemical budgets under no precipitation. During the pycnal stratification of May–September, the lake exhibited a four-layer structure with different temperature and EC25 values, probably due to the lower intrusion of groundwater passing through three different pathways. The four-layer structure disappeared due to vertical mixing in October–December and March–April and inverse stratification in January–February. The G_out and G_in values were estimated for three budget periods in the mixing season. Utilizing Darcy’s law for the G_out values as a confined groundwater flow, it is found out that G_out has a linear relationship with lake volume. The relatively high G_in and G_out values estimated are probably caused by the high permeability of lacustrine sand and gravel deposited as bedrock, which furnishes the high adjustability to lake level, i.e., its small variation at ca. 0.5 m in amplitude. Full article

Meteorological, soil, and hydrological droughts are among the most important phenomena affecting the natural environment and water management. Prolonged precipitation deficits often result in low river flows, reducing water resources and degrading aquatic ecosystems. This study evaluates the potential of meteorological drought indices as predictors of observed low flows. Long-term meteorological and hydrological data, including precipitation and river discharge records, were analyzed for the Biała Lądecka River catchment in Lower Silesia, southwestern Poland. Meteorological drought was characterized using the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI) calculated for 1-, 3-, and 6-month timescales, together with corresponding one- and two-week indices. Relationships between drought index values and observed low flows were analyzed while accounting for the time lag of the catchment response. The predictive performance of individual indices was evaluated to determine their suitability for water resource monitoring and management. The results show that meteorological drought indices can effectively indicate the occurrence of low flows, although the strength of the relationships depends on the adopted timescale. Both classical and short-term indices proved useful for analyzing the development of hydrological drought and have potential applications in low-flow monitoring and early warning systems. Full article

Recovering nitrogen from wastewater is vital for a circular economy, yet conventional air stripping is limited by aerodynamic backpressure and CO₂-induced pH drops. This study evaluates a novel pilot-scale engineering approach for municipal reject water, integrating chemical phosphorus precipitation with a fundamentally redesigned ammonia stripping column. Upstream calcium hydroxide dosing achieved >99.9% phosphorus recovery and spontaneously alkalized the effluent (pH > 12.1), eliminating supplementary caustic addition. The downstream stripping column utilized negative-pressure (vacuum) operation and high-pressure liquid atomization to maximize mass transfer while preventing flooding and alkalinity neutralization. Comprehensive on-site testing established a clear mathematical relationship between aerodynamics and efficiency. Results demonstrate that high-efficiency recovery requires gas-to-liquid (G/L) ratios exceeding 70:1, a threshold uniquely unlocked by this negative-pressure design. Under optimal conditions, the continuous-flow system achieved 87.6% ammonia removal. A low-resistance acid scrubber captured ~100% of the volatilized ammonia (exhaust 0–1 ppm), producing a concentrated ammonium sulfate bio-fertilizer. This integrated technology provides a scalable, applied engineering blueprint for advancing sustainable Water Resource Recovery Facilities. Full article

Climate change is altering global temperature and precipitation patterns, with particularly strong effects expected in Mediterranean regions, where reduced groundwater recharge and increased evapotranspiration may affect groundwater-dependent ecosystems. This study provides a preliminary, indicator-based assessment of the potential sensitivity of the Cabecera del Bornova Groundwater Body (Guadalajara, Spain), which sustains the Somolinos karst wetland, under natural conditions and protected as a Natural Groundwater Reserve and Natural Lacustrine Reserve. Empirical correlations were established between accumulated deviations of historical precipitation and observed piezometric levels in two monitoring piezometers using second-degree polynomial functions. The most informative relationships were obtained for piezometer ZE01, particularly at the daily scale, whereas the second piezometer showed weaker relationships. These functions were applied to regionalized climate projections generated with the FICLIMA methodology from ten CMIP6 models under SSP1-2.6, SSP2-4.5, SSP3-7.0 and SSP5-8.5 scenarios from the IPCC Sixth Assessment Report. The results indicate a general decreasing tendency in empirical piezometric-level indicators throughout the 21st century, although the magnitude of the response is highly sensitive to the selected rainfall station, temporal resolution, climate model and scenario. Extreme projected declines are interpreted as extrapolation-sensitive outputs rather than deterministic predictions of aquifer drawdown or groundwater-reserve depletion. Direct impacts on lagoon level, spring discharge or wetland extent cannot be quantified with the dataset. The results highlight the need to expand piezometric monitoring, instrument the Manadero del Bornova spring, monitor lagoon water levels and develop physically based recharge and groundwater-flow models. Full article

Assessing nitrate sensitivity to hydroclimatic variability is important for evaluating water-quality vulnerability under hydroclimatic variations in coupled surface-water and groundwater systems. This study applies a hybrid, scenario-based projection framework combining a Long Short-Term Memory (LSTM) model and Weighted Regression on Time, Discharge, and Season with Projections (WRTDS-P) to examine nitrate plus nitrite responses under idealized wet and dry conditions across seven U.S. river basins and three associated groundwater wells. LSTM projections evaluate conditional sensitivity to altered precipitation forcing, while WRTDS-P projections assess discharge-conditioned responses based on empirically derived concentration–discharge relationships. Results show strong basin-scale heterogeneity in nitrate sensitivity. Agriculturally dominated Midwestern and central U.S. basins generally exhibit higher nitrate concentrations under the idealized wet scenarios, whereas basins influenced by groundwater buffering, flow regulation, or managed hydrology show weak or slightly negative wet–dry responses. For the three evaluated wells, groundwater projections show site-specific damped or delayed responses relative to nearby surface-water systems, reflecting aquifer storage and legacy nitrogen effects, although the Illinois well shows a larger projected wet–dry amplitude than the associated river. Cross-framework comparison reveals moderate agreement in response direction but notable differences in magnitude, highlighting sensitivity to model structure and forcing assumptions. These findings emphasize the value of hybrid projection frameworks for cross-framework sensitivity analysis and for interpreting nitrate vulnerability under hydroclimatic variation while accounting for uncertainty across surface-water and groundwater systems. Full article

This study investigated the relationship between precipitation indicators and water availability in the Muriaé River Basin (MRB), Southeast Brazil, using rainfall and streamflow series from 1961 to 2020. Monthly mean precipitation (MMP), the total annual precipitation (PRCPTOT), the Rainfall Anomaly Index (RAI), and the Q95 low flow parameter were analyzed to evaluate hydrological variability and drought conditions. Trend analyses were performed using the Mann–Kendall test and Sen’s slope estimator, and Pearson correlation analysis was applied to assess the relationship between precipitation and low flow availability. The results showed marked temporal variability in precipitation and hydrological conditions throughout the basin. Although statistically significant increasing trends in annual precipitation were identified at Carangola and Patrocínio do Muriaé, no generalized long-term reduction in precipitation was observed in the MRB. In contrast, Q95 exhibited reductions at all monitored stations, with decadal decreases ranging from approximately 31% at Carangola to 56% at Itaperuna. The RAI analysis indicated predominance of very dry and extremely dry events during the most recent decade, coinciding with reduced low flow availability. The results indicate that changes in water availability are linked to the temporal distribution and persistence of dry anomalies. These findings can influence decisions in hydrological monitoring and water resource management strategies in the basin. Full article