Journal of Hydrology-Regional Studies最新文献

{"title":"Identification of inflow sources and pathways to a waste rock dump located in a former river channel in a mountainous abandoned mine of Japan: A case study 60 years post-construction","authors":"Shinji Matsumoto ,&nbsp;Sereyroith Tum ,&nbsp;Tagiru Ogino ,&nbsp;Miu Nishikata ,&nbsp;Tetsuo Yasutaka ,&nbsp;Tomoko Oguri ,&nbsp;Tsuyoshi Shintani","doi":"10.1016/j.ejrh.2025.102645","DOIUrl":"10.1016/j.ejrh.2025.102645","url":null,"abstract":"<div><h3>Study region</h3><div>A legacy underground mine located in a mountainous region of Hokkaido, northern Japan.</div></div><div><h3>Study focus</h3><div>The concentrations of dissolved ions and stable water isotopes (δ¹⁸O and δ²H) in surface water from surrounding rivers and groundwater near a waste rock dump (WD) were analyzed. Continuous water quality monitoring was performed using data loggers. Tracer tests using NaCl were also performed in the rivers. Time-series analysis and correlation studies elucidated the origins and pathways of water inflow to the WD.</div></div><div><h3>New hydrological insights for the region</h3><div>Water inflow into the WD predominantly originated from groundwater in the surrounding mountainous terrain and river water, serving as the primary contributors to mining-influenced water (MIW). The inflow volumes and MIW generation increased during precipitation events and snowmelt periods. These processes could have been influenced by the degradation of impermeable structures around the WD, emphasizing the need for continuous water quality monitoring and repair of these structures. This research highlights the necessity of long-term planning for WD management, considering regional climatic and topographic characteristics, to mitigate water pollution risks. It provides new insights into reducing environmental impacts and enhancing the sustainability of mining operations in mountainous regions. Moreover, this study demonstrates that a combination of hydrological approaches—water quality analysis, isotopic studies, and tracer tests—is a valuable tool for gathering critical information on MIW in mountainous mining regions.</div></div>","PeriodicalId":48620,"journal":{"name":"Journal of Hydrology-Regional Studies","volume":"61 ","pages":"Article 102645"},"PeriodicalIF":5.0,"publicationDate":"2025-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144858307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhanced groundwater potential mapping using a GIS based chaotic sparrow search algorithm optimized weighted broad learning system: A case study of the Guozhuang spring region, northern China","authors":"Dekang Zhao ,&nbsp;Fan Miao ,&nbsp;Yongqi Chen ,&nbsp;Qiang Wu ,&nbsp;Guorui Feng ,&nbsp;Bofeng Chang ,&nbsp;He Su ,&nbsp;Peiyuan Ren ,&nbsp;Chenwei Hao ,&nbsp;Zhenghao Li ,&nbsp;Xiang Li ,&nbsp;Jiaying Cai","doi":"10.1016/j.ejrh.2025.102708","DOIUrl":"10.1016/j.ejrh.2025.102708","url":null,"abstract":"<div><h3>Study region</h3><div>Guozhuang spring area, Shanxi, North China.</div></div><div><h3>Study focus</h3><div>This study proposes a Chaotic Sparrow Search Algorithm-enhanced Weighted Broad Learning System (CSSA-WBLS) for groundwater potential assessment. The framework mitigates data imbalance via instance weighting in WBLS and enhances parameter optimization using chaotic operators within CSSA.</div></div><div><h3>New hydrological insights for the region</h3><div>Groundwater is a critical freshwater resource for sustainable water supply management. However, evaluating its potential faces two key challenges: severe data imbalance (fewer spring occurrence samples than non-spring samples) and suboptimal parameter optimization in existing models. Geospatial data were compiled using GIS analysis and field surveys. Eleven predictive factors spanning geology, hydrology, and anthropogenic influences were identified using the frequency ratio, random forest feature importance, and multicollinearity diagnostics. A dataset exhibiting a 1:10 spring/non-spring ratio was split into training (70 %) and testing (30 %) sets. BLS and WBLS models were hybridized with the Sparrow Search Algorithm (SSA) and CSSA to optimize network architecture and node parameters, addressing SVM limitations with imbalanced data. Model performance under imbalance was evaluated using ROC-AUC, accuracy, sensitivity, specificity, balanced accuracy, F1-score, confusion matrices, and Friedman testing. CSSA-WBLS achieved superior performance across over all metrics (AUC = 0.874) and effectively addressed data imbalance. Spatial mapping identified 18.78 % of the area as high-potential groundwater zones. CSSA-WBLS thus provides an efficient framework for groundwater assessment and has significant potential for regional applications.</div></div>","PeriodicalId":48620,"journal":{"name":"Journal of Hydrology-Regional Studies","volume":"61 ","pages":"Article 102708"},"PeriodicalIF":5.0,"publicationDate":"2025-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144852756","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of slope and upslope inflow rate on black soil ephemeral gully erosion processes in the Northeastern China","authors":"Yazhe Li ,&nbsp;Changjia Li ,&nbsp;Zhongwu Li ,&nbsp;Gaozheng Zhang ,&nbsp;Weihao Hu ,&nbsp;Qianxi Xue ,&nbsp;Chunmei Wang ,&nbsp;Enheng Wang","doi":"10.1016/j.ejrh.2025.102692","DOIUrl":"10.1016/j.ejrh.2025.102692","url":null,"abstract":"<div><h3>Study region</h3><div>Black soil region in the Northeastern China</div></div><div><h3>Study focus</h3><div>Ephemeral gullies serve as major sediment sources in Northeast China which can substantially reduce land productivity. Gully erosion processes, hydraulic mechanisms, and threshold values governing the transformation from ephemeral to permanent gullies in black soil regions under water erosion conditions remain insufficiently explained. To address this, laboratory simulations were conducted using an artificial ephemeral gully constructed from black soil, representing conditions in northeastern China. The design incorporated three slope gradients (3°, 6°, and 9°) and five upslope inflow rates (10, 20, 30, 40, and 50 L/min). Data collection involved measuring runoff and sampling sediment to derive hydraulic parameters. Statistical analyses were performed using Spearman rank correlation, multiple regression, and threshold models.</div></div><div><h3>New hydrological insights for the region</h3><div>Sediment yield increases 4 times more from 6°-9° than from 3°-6°, primarily due to the transition from subcritical to supercritical flow. The sediment yield followed a pattern of initial increase to a peak value, then a gradual decline, while the sediment yield rate demonstrated a stepwise rise with increasing upslope inflow rates. Critical hydraulic thresholds for the transformation from ephemeral to permanent gullies were identified across multiple parameters: mean flow velocity (0.44 m/s), flow shear stress (17.45 N/m²), flow power (8.62 W/m²), and unit flow power (0.05 m/s). This research examines key features and processes of ephemeral gully erosion, establishing a theoretical basis for control strategies in black soil regions.</div></div>","PeriodicalId":48620,"journal":{"name":"Journal of Hydrology-Regional Studies","volume":"61 ","pages":"Article 102692"},"PeriodicalIF":5.0,"publicationDate":"2025-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144842469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Future drought patterns in Southwest China: A CMIP6-based analysis using multiple drought indices","authors":"Yinping Long ,&nbsp;Yunfei Huang ,&nbsp;Qimin Ma ,&nbsp;Wenli Yu ,&nbsp;Chunping Tan","doi":"10.1016/j.ejrh.2025.102702","DOIUrl":"10.1016/j.ejrh.2025.102702","url":null,"abstract":"<div><h3>Study region</h3><div>southwest China</div></div><div><h3>Study focus</h3><div>This study examines future drought patterns in Southwest China—a humid yet drought-prone region—focusing on trends in drought indices, changes in duration, frequency, and intensity, and their impacts on agriculture. Temperature and precipitation from 20 CMIP6 models were downscaled using the high-resolution China Meteorological Forcing Dataset (CMFD), and the multi-model ensemble was used to calculate four drought indices: Standardized Precipitation Index (SPI), China-Z Index (CZI), Standardized Precipitation Evapotranspiration Index (SPEI), and nonstationary SPEI (NSPEI).</div></div><div><h3>New hydrological insights for the region</h3><div>SPI and CZI indicate wetter trends under all SSPs, while SPEI and NSPEI project intensified drought risks, especially under SSP3–7.0 and SSP5–8.5. SPI and CZI show an \"increase-then-decrease\" pattern in frequency and duration, with stable intensity, while SPEI exhibits a \"decrease-then-increase\" trend across metrics. NSPEI reveals higher extremes and sustained increases in frequency and intensity. Over half of the cropland may be exposed to future droughts, particularly single rice (up to 29,446 km²), single maize (26,733 km²), and single wheat (6106 km²). The Sichuan Basin, as a persistent hotspot, may experience drought exposure of up to 17,755 km² for rice and 11,434 km² for maize. The findings highlight critical regional disparities and stress the urgency of drought adaptation strategies.</div></div>","PeriodicalId":48620,"journal":{"name":"Journal of Hydrology-Regional Studies","volume":"61 ","pages":"Article 102702"},"PeriodicalIF":5.0,"publicationDate":"2025-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144827829","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Suspended material retention in riverine reservoirs: Role of hydropeaking, density currents, and settling velocity","authors":"Siyoon Kwon ,&nbsp;Il Won Seo ,&nbsp;Inhwan Park ,&nbsp;Jun Song Kim","doi":"10.1016/j.ejrh.2025.102706","DOIUrl":"10.1016/j.ejrh.2025.102706","url":null,"abstract":"<div><h3>Study Region</h3><div>Paldang Lake (PL), a riverine reservoir in South Korea, located at the confluence of three major rivers.</div></div><div><h3>Study Focus</h3><div>This study evaluates the retention and transport mechanisms of suspended materials within PL. We employed calibrated hydrodynamic and temperature models integrated with a Lagrangian particle tracking framework to simulate the behavior of fine and coarse particles under three distinct flow regimes: hydropeaking, non-hydropeaking, and flood events. The analysis highlights the role of hydropeaking operation, density currents, and particle settling in modulating particle pathways and residence times.</div></div><div><h3>New Hydrological Insights for the Region</h3><div>Our simulations reveal that hydropeaking flows significantly enhance lateral mixing and extend the residence times of fine particles, while coarse particles remain less mobile due to interactions with bed roughness. Stratified flow at confluences inhibits mixing between tributary inflows, leading to bimodal residence time distributions that highlight the importance of weak-flow zones as retention hotspots. During flood events, strong advective forces dominate, resulting in uniform particle transport regardless of settling velocity. These findings provide a deeper understanding of how hydrodynamic forces, stratification, and particle properties influence suspended material retention in PL, offering practical insights for optimizing dam operations and reservoir management to improve water quality and ensure long-term sustainability.</div></div>","PeriodicalId":48620,"journal":{"name":"Journal of Hydrology-Regional Studies","volume":"61 ","pages":"Article 102706"},"PeriodicalIF":5.0,"publicationDate":"2025-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144827825","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A multi-model study of the subsurface and surface hydrodynamics of a 700 km2 watershed in western Canada (Fox Creek area, Alberta)","authors":"Bárbara Meneses-Vega ,&nbsp;Claudio Paniconi ,&nbsp;Christine Rivard ,&nbsp;Laura Guarin-Martinez","doi":"10.1016/j.ejrh.2025.102637","DOIUrl":"10.1016/j.ejrh.2025.102637","url":null,"abstract":"<div><h3>Study region</h3><div>A 700 km² watershed near the town of Fox Creek (west-central Alberta, Canada), a region that has seen intensive oil and gas production since the 1950s, is investigated.</div></div><div><h3>Study focus</h3><div>The overall objective is to improve our understanding of the hydrodynamics of this watershed. The hierarchical multi-model approach uses physically based numerical models and follows a stepwise progression, transitioning from saturated and variably saturated groundwater to integrated surface water–groundwater (SW-GW) models. This progression encompasses 2D and 3D configurations from a deep (∼1 km) hydrogeological multi-layer aquifer system to a shallow (45 m) coupled flow system. This differs from other multi-model studies where the focus is on comparing simple to complex models for a fixed domain.</div></div><div><h3>New hydrological insights for the region</h3><div>The hierarchical modeling approach has led to better insights and estimates of processes including vertical recharge and lateral groundwater contributions. Moreover, it allowed us to corroborate hydraulic conductivity values and groundwater recharge despite the limited dataset. The hydraulic connections between the four non-marine bedrock units were shown to be negligible, allowing us to focus on the Paskapoo Formation. The unsaturated zone was shown to play a significant role in the model response, and accounting for land surface–subsurface dynamics was demonstrated to be critical to properly estimating hydraulic head profiles and land surface saturation patterns.</div></div>","PeriodicalId":48620,"journal":{"name":"Journal of Hydrology-Regional Studies","volume":"61 ","pages":"Article 102637"},"PeriodicalIF":5.0,"publicationDate":"2025-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144828568","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessing the impact of hydro-climatic factors on surface water quality: A global review and synthesis","authors":"Apoorva Bamal ,&nbsp;Md Galal Uddin ,&nbsp;Agnieszka I. Olbert","doi":"10.1016/j.ejrh.2025.102677","DOIUrl":"10.1016/j.ejrh.2025.102677","url":null,"abstract":"<div><h3>Study region</h3><div>Global, with emphasis on diverse climatic and geographic regions impacted by hydro-climatic variability.</div></div><div><h3>Study focus</h3><div>This review investigates the influence of hydro-climatic parameters—such as precipitation, temperature, runoff, and streamflow—on surface water quality (WQ), incorporating both natural climatic variability and anthropogenic climate change. It synthesizes findings from 71 peer-reviewed studies using PRISMA guidelines, focusing on methodological approaches and key hydro-climatic drivers affecting WQ.</div></div><div><h3>New hydrological insights for the region</h3><div>Findings reveal that hydro-climatic factors significantly impact individual WQ parameters and overall WQ status. While precipitation and temperature are widely studied, variables like windspeed and relative humidity remain underexplored, potentially limiting the understanding of climate–WQ interactions. Most studies rely on statistical or hydrological models, which often fail to capture complex, nonlinear relationships. The integration of advanced machine learning (ML) and artificial intelligence (AI) methods shows promise in improving predictive accuracy and uncovering hidden patterns. However, few studies assess the cumulative or synergistic effects of multiple hydro-climatic variables. Future research should adopt multidisciplinary, integrated modeling frameworks to better represent dynamic interactions under climate change scenarios. Long-term environmental monitoring and adaptive management strategies are essential for enhancing WQ resilience. To the best of the authors’ knowledge, this review is among the first to comprehensively assess the interplay of multiple hydro-climatic drivers on surface WQ, offering critical insights for more informed water resource management and climate adaptation policy.</div></div>","PeriodicalId":48620,"journal":{"name":"Journal of Hydrology-Regional Studies","volume":"61 ","pages":"Article 102677"},"PeriodicalIF":5.0,"publicationDate":"2025-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144827826","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rainfall and groundwater isotopes to investigate aquifer recharge mechanisms and seasonality in the Mediterranean region. Implications for long-term groundwater sustainability in the climate change context","authors":"B. Nlend ,&nbsp;F. Huneau ,&nbsp;E. Garel ,&nbsp;S. Santoni ,&nbsp;T. Leydier","doi":"10.1016/j.ejrh.2025.102671","DOIUrl":"10.1016/j.ejrh.2025.102671","url":null,"abstract":"<div><h3>Study region</h3><div>The Western Mediterranean Region with a focus on Corsica Island.</div></div><div><h3>Study focus</h3><div>Groundwater recharge, a complex component of the water cycle, highly sensitive to climate change and controlled by other several factors. Based on long-term records of precipitation stable isotopes and groundwater through different sites, this paper aims to analyze the groundwater response to rainfall input and thus to define the different recharge mechanisms in various geomorphological and geological settings.</div></div><div><h3>New hydrological insights for the region</h3><div>Results show various patterns of groundwater recharge in alluvium, limestone and basement with greatest variability in rainwater infiltration in alluvial systems. Groundwater recharge ratios in coastal areas are similar in winter and summer periods while in inland areas the summer recharge is negligible. An assessment of the rainwater signal damping was conducted and revealed a limited influence of plants while the direct control of climatic regime through snowpack, precipitation intensity and evaporation is highlighted. The evaporation mechanism in groundwater, investigated using deuterium-excess and line-conditioned excess, is mainly related to a connection between rivers and aquifers. This work provides a clear understanding of aquifer response to meteorological conditions in the Mediterranean region. Groundwater is not just a weighted mean of rainfall events but rather reflects a complex eco-hydro-meteorological system. These results are beneficial for the development of sustainable water management practices according to the climate scenarios.</div></div>","PeriodicalId":48620,"journal":{"name":"Journal of Hydrology-Regional Studies","volume":"61 ","pages":"Article 102671"},"PeriodicalIF":5.0,"publicationDate":"2025-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144828570","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Causes of baseflow variation in an inland river watershed of Northwest China","authors":"Mengwei Song ,&nbsp;Hailong Liu ,&nbsp;Quanlong Wu ,&nbsp;Aminjon Gulakhmadov ,&nbsp;Firdavs Shaimuradov","doi":"10.1016/j.ejrh.2025.102698","DOIUrl":"10.1016/j.ejrh.2025.102698","url":null,"abstract":"<div><h3>Study area</h3><div>The study area is the inland river watershed of northwest China, the upper Manas River basin.</div></div><div><h3>Study focus</h3><div>Baseflow serves as a critical component for water resource management during dry seasons in arid regions. The formation mechanisms of baseflow are governed by multiple factors including watershed characteristics (area and topography) and runoff generation processes (rainfall versus snowmelt dominance). To investigate the drivers of baseflow dynamics in northwest China's Manas River watershed, we employed multi-source remote sensing data to identify the optimal baseflow separation method. Furthermore, the impacts of hydroclimatic variables and vegetation conditions on baseflow were quantitatively evaluated through explainable machine learning approaches, specifically Categorical Boosting (CatBoost) coupled with SHapley Additive exPlanations (SHAP) analysis.</div></div><div><h3>New hydrological insights for the region</h3><div>The results demonstrate that the Eckhardt filtering method provides optimal performance for comparative evaluation of baseflow separation in the watershed. Our analysis reveals significant influences of multiple hydroclimatic variables on baseflow dynamics: Normalized Difference Vegetation Index (NDVI), snow depth (SD), precipitation (Prec), surface air temperature (Temp), solar radiation (SR), profile soil moisture (PSM), and snow cover area (SCA). Among these, NDVI exhibits particularly pronounced effects.These factors collectively induce an approximate two-week delay in baseflow formation processes. Quantitative analysis shows SD has the shortest lag period (12.45 ± 8.50 days), while SR (14.16 ± 6.67 days) and Temp (14.89 ± 7.58 days) demonstrate comparable delay durations. Notably, all observed lag times fall within a 22-day window without statistically significant differences. Furthermore, spectral analysis identified 3-month to semi-annual oscillations between hydroclimatic variations and baseflow responses, potentially explaining observed seasonal patterns in baseflow dynamics. This study provides valuable insights into baseflow generation mechanisms in inland river basins, with particular relevance for water resource management in arid regions.</div></div>","PeriodicalId":48620,"journal":{"name":"Journal of Hydrology-Regional Studies","volume":"61 ","pages":"Article 102698"},"PeriodicalIF":5.0,"publicationDate":"2025-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144827827","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydrological responses to land use changes and precipitation variability in Southern Brazil","authors":"Aydoğan Avcıoğlu ,&nbsp;Rosalie Vandromme ,&nbsp;Thomas Grangeon ,&nbsp;Jean Paolo Gomes Minella ,&nbsp;Olivier Evrard ,&nbsp;Marcos Tassano ,&nbsp;Néverton Scariot ,&nbsp;Olivier Cerdan","doi":"10.1016/j.ejrh.2025.102705","DOIUrl":"10.1016/j.ejrh.2025.102705","url":null,"abstract":"<div><h3>Study region</h3><div>Meridional plateau, Uruguay River Basin, Southern Brazil</div></div><div><h3>Study focus</h3><div>This study investigates the relative impacts of rainfall and LULC changes on streamflow variations over the Meridional plateau in the region comprising the Uruguay River basin in Southern Brazil. We used MapBiomas annual LULC data set and the CAMELS-BR data set by aggregating daily observations from gauging stations (rainfall and streamflow) to annual indices from 1985 to 2018. We employed time series and trend analysis across three identified clusters with 78 gauging stations through an unsupervised machine learning algorithm.</div></div><div><h3>New hydrological insights for the regions</h3><div>We found an extensive and statistically significant agricultural expansion for soybean croplands following a transition from other temporary crops (i.e., maize, wheat, oats, etc.), which was accompanied by statistically significant runoff coefficient decrease (i.e., 34 %), while the results for rainfall and flow were statistically insignificant. Furthermore, we observed a 27 % rise in water demand linked to the expansion of soybean croplands, a phenomenon corroborated by existing research. The growth in the number and capacity of dams further may reinforce these findings across the analyzed periods. The identified remarkable decrease in runoff coefficient may, therefore, be primarily attributed to LULC changes. Our findings might provide insights for improved water resource management for future land use planning to develop more resilient catchments against changing environmental and climatic conditions.</div></div>","PeriodicalId":48620,"journal":{"name":"Journal of Hydrology-Regional Studies","volume":"61 ","pages":"Article 102705"},"PeriodicalIF":5.0,"publicationDate":"2025-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144827828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}