Hydrological Processes最新文献

{"title":"Soil Genetic Horizons Regulate Water Uptake by Picea schrenkiana in Arid Mountain Forests","authors":"Tian Shengchuan,&nbsp;Zhang Bin,&nbsp;Du Lan,&nbsp;Zhao Nan,&nbsp;Zheng Xinjun,&nbsp;Tang Lisong,&nbsp;Wang Yugang,&nbsp;Li Yan","doi":"10.1002/hyp.70678","DOIUrl":"https://doi.org/10.1002/hyp.70678","url":null,"abstract":"<div>\u0000 \u0000 <p>Mountain forests in arid regions are under long-term water limitation, and different soil genetic horizons have distinct differences in water storage and root accessibility. Therefore, investigating the relationship between plant water uptake patterns and soil genetic horizons in arid mountain forests can help distinguish the hydrological functions of different soil horizons. In this study, we investigated <i>Picea schrenkiana</i> forests in the Tianshan Mountains at three elevations: 2200, 1800 and 1450 m. During the growing seasons over two consecutive years, soil water from the humus, eluvial and illuvial horizons, together with plant xylem water, was collected and the MixSIAR model was used to quantify the contributions of different soil genetic horizons to water uptake by <i>P. schrenkiana</i>. The results showed that during a wetter year and the early growing season, trees mainly used water from the humus horizon, whereas during a drier year or the late growing season, they increased their uptake of water from the eluvial and illuvial horizons. Along the elevational gradient, <i>P. schrenkiana</i> at 2200 and 1800 m mainly used water from the humus horizon. However, at 1450 m, influenced by root distribution and hydraulic connectivity, <i>P. schrenkiana</i> mainly used water from the eluvial horizon even when the humus horizon had relatively high soil water content. This study indicates that the humus horizon is an important water source for <i>P. schrenkiana</i>, and its role in maintaining forest hydrological health may exceed that of the eluvial and illuvial horizons. Higher soil water content does not necessarily indicate a higher contribution to plant water uptake, as plant water uptake is also related to root distribution, water availability and atmospheric drought stress. This study clarifies the important ecohydrological role of the humus horizon in arid mountain forests and helps improve our understanding of the mechanisms underlying tree water uptake in these ecosystems.</p>\u0000 </div>","PeriodicalId":13189,"journal":{"name":"Hydrological Processes","volume":"40 9","pages":""},"PeriodicalIF":3.1,"publicationDate":"2026-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148942284","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Drought Propagates Asynchronously Across Hydrological Compartments: Stage Differences in Propagation Time and Implications for Drought Monitoring","authors":"Hu Tao,&nbsp;Yibo Wang,&nbsp;Zhongyang Zhang,&nbsp;Zeyong Gao","doi":"10.1002/hyp.70683","DOIUrl":"https://doi.org/10.1002/hyp.70683","url":null,"abstract":"<div>\u0000 \u0000 <p>Drought propagation across hydrological compartments is not a synchronous process, yet stage-specific differences between the Stage 1 (meteorological-to-soil link) and the Stage 2 (soil-to-groundwater link) remain insufficiently understood. Using China as a hydroclimatically diverse test domain, this study established a two-stage drought propagation framework linking SPI, SSI and GWSA-DSI and combined propagation-time analysis with AC1 (first-order autocorrelation) and partial-correlation diagnostics. Results showed that drought propagated rapidly from meteorological to soil conditions, with lag times of 1.2–4.1 months, whereas propagation from soil drought to groundwater drought was consistently slower, with lag times of 2.6–5.9 months. The slower Stage 2 was characterized by generally lower short-term temporal persistence and weaker conditional associations with concurrent hydroclimatic forcing. Antecedent soil moisture showed a strong and spatially consistent association with current SSI, whereas its relationship with GWSA-DSI was substantially weaker and regionally heterogeneous. These findings show that drought propagation is stage-dependent across hydrological compartments, with deeper storage responding more slowly. This process-based asymmetry implies that rapid changes in near-surface indicators do not necessarily indicate equally rapid development or recovery of deeper hydrological drought.</p>\u0000 </div>","PeriodicalId":13189,"journal":{"name":"Hydrological Processes","volume":"40 9","pages":""},"PeriodicalIF":3.1,"publicationDate":"2026-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148942058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Declining Runoff Efficiency and Storage Reorganisation in the Source Region of the Yellow River Under Climate Warming, 1974–2025","authors":"Yong Luo,&nbsp;Yang Si,&nbsp;Linrui Ma,&nbsp;Shenglong Gu,&nbsp;Haichao Yang","doi":"10.1002/hyp.70674","DOIUrl":"https://doi.org/10.1002/hyp.70674","url":null,"abstract":"<div>\u0000 \u0000 <p>The source region of the Yellow River (SRYR) has become warmer and wetter, but annual runoff has not increased proportionally, suggesting that a comparatively stable water yield may conceal a reorganisation of runoff generation. A 52-year hydroclimatic record (1974–2025) was analysed by integrating change-point diagnostics, cumulative precipitation-runoff analysis, water-resource accounting, satellite-era storage and cryospheric indicators, seasonal runoff coefficients and Eckhardt baseflow separation. The slope of the cumulative precipitation-runoff relation decreased by 13.3% around 1989. The runoff coefficient shifted in 1997, preceding the dominant runoff-volume shift in 1999. Relative to 1974–1989, precipitation during 2013–2025 increased by 20.0%, whereas runoff increased by only 2.3% and the runoff coefficient decreased by 14.9%. The accounting-based groundwater-resource ratio increased by 36.5%. Summer and autumn runoff coefficients decreased by 21.6% and 21.1%, respectively, whereas the winter coefficient increased by 29.9% and the baseflow index rose from 0.614 to 0.694. Concurrent increases in terrestrial water-storage anomaly, soil moisture, model-derived active-layer thickness and evapotranspiration, together with fewer cold-season snow-cover days, were consistent with greater warm-season retention and consumption and enhanced delayed release. The temporal sequence and convergence of these diagnostics indicate that recent wetting restored runoff volume without restoring the earlier high-efficiency runoff regime. Annual runoff alone therefore underrepresents changes in storage dependence, seasonal water availability and climate sensitivity in warming alpine headwaters.</p>\u0000 </div>","PeriodicalId":13189,"journal":{"name":"Hydrological Processes","volume":"40 9","pages":""},"PeriodicalIF":3.1,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148860110","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Differences in Water-Holding Capacity Across Litter Strata and Composition in Pinus massoniana Conifer-Broadleaf Mixed Forest Stands in Subtropical Mountains","authors":"Ye-Tong Wang,&nbsp;Ming Xu,&nbsp;Cheng Chen,&nbsp;Jian Zhang","doi":"10.1002/hyp.70677","DOIUrl":"https://doi.org/10.1002/hyp.70677","url":null,"abstract":"<div>\u0000 \u0000 <p>Litter layers are crucial for forest eco-hydrology, yet the contribution of different sublayers to litter water-holding capacity (LWHC) and the underlying mechanisms are poorly understood, especially for the semi-decomposed sublayer. This study investigated this issue in three <i>Pinus massoniana</i> stand types in southwestern China: <i>P. massoniana-Liquidambar formosana</i> mixed forest (Pm + Lf, conifer-deciduous broadleaf), <i>P. massoniana-Castanopsis eyrei</i> mixed forest (Pm + Ce, conifer-evergreen broadleaf), and pure <i>P. massoniana</i> plantation (Pm). Litter was collected based on a refined stratification: undecomposed (A), slightly decomposed (B1) and broken decomposed (B2) sublayers. We measured litter mass, leaf morphological characteristics, humification indices and LWHC via immersion experiments under both natural and artificially mixed conditions. Results showed that while total litter mass did not differ significantly among stand types, the mass of coniferous and broadleaf components differed significantly between pure and mixed forests (<i>p</i> &lt; 0.05). Humification degree consistently increased from the A to the B2 sublayer across all stands (<i>p</i> &lt; 0.05). LWHC varied significantly with both stand type and sublayer (<i>p</i> &lt; 0.05). For a given sublayer, the order was Pm + Lf &gt; Pm + Ce &gt; Pm; among sublayers, it was B2 &gt; B1 &gt; A. Artificially mixed treatments confirmed that LWHC increased significantly with the proportion of broadleaf litter and decomposed litter (B1, B2) (<i>p</i> &lt; 0.01). The contribution per unit mass to LWHC ranked as B2 (45.48%–48.30%) &gt; B1 (27.81%–31.07%) &gt; A (23.45%–23.89%), while the contribution per unit area was B2 (50.86%–61.24%) &gt; A (21.83%–26.14%) &gt; B1 (16.93%–23.00%). LWHC was significantly correlated with litter composition, humification degree and leaf morphological characteristics (<i>p</i> &lt; 0.05). This refined stratification of litter sublayers provides a novel understanding of the mechanisms driving the eco-hydrological functions of forest litter.</p>\u0000 </div>","PeriodicalId":13189,"journal":{"name":"Hydrological Processes","volume":"40 9","pages":""},"PeriodicalIF":3.1,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148942238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Decoupling of Dissolved and Colloidal Export Across the Hydrograph of an Early Pedogenic Stage Critical Zone Observatory","authors":"M. Gelin,&nbsp;J. Bouchez,&nbsp;M. Tharaud,&nbsp;C. J. Cunningham,&nbsp;J. Chorover,&nbsp;M. F. Benedetti","doi":"10.1002/hyp.70675","DOIUrl":"https://doi.org/10.1002/hyp.70675","url":null,"abstract":"<p>This study investigates colloid transport under early weathering conditions using the Landscape Evolution Observatory (LEO), a set of three replicated mesoscale basaltic hillslopes located in Tucson, Arizona. The hillslopes were subjected to a controlled irrigation regime designed to mimic natural wetting–drying cycles, potentially enhancing the in situ formation of colloids. After only 12 years of weathering, the hillslopes remain in an early pedogenic stage and have not yet developed vertical horizon differentiation. This structural homogeneity and textural isotropy make LEO an ideal experimental platform for investigating the mechanisms governing the mobilisation of weathering-derived colloids. During a one-month infiltration experiment, dissolved elements (Na, Mg, Al, Si, K, Ca, Fe) and their colloidal counterparts (Al, Fe) were monitored daily, the latter being analysed using high-resolution inductively coupled plasma mass spectrometry in single particle mode (spHR-ICP-MS). This analytical approach allowed us to examine the concentration variations and mass distribution of colloids in response to changes in hydrologic discharge rate across the hydrograph. Results show that export is dominated by the dissolved fraction even for nominally insoluble phases (e.g., Al, Fe) and that the maximum instantaneous colloidal flux occurs during the recession of infiltration events. No significant relationship is observed between discharge and concentration, neither for dissolved nor colloidal forms of Fe and Al. However, for any given element, the dissolved and colloidal fractions do not follow the same dynamics in response to the discharge surge, suggesting distinct geochemical and hydrological controls. This study provides evidence of the role played by the development of the upper soil horizon in the export of colloids from soils and hillslopes by rivers during high-flow periods, using an experimental hillslope with weak vertical contrasts (mineralogy, hydraulic conductivity) as an end-member system.</p>","PeriodicalId":13189,"journal":{"name":"Hydrological Processes","volume":"40 9","pages":""},"PeriodicalIF":3.1,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hyp.70675","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148860111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Using In Situ Monitoring to Assess How Flood Intensity Can Be Inferred From Lake Sedimentary Archives (Kamech, Tunisia)","authors":"Sabatier Pierre,&nbsp;Raclot Damien,&nbsp;Hamdi Radhouane,&nbsp;Dellinger Mathieu,&nbsp;Molard Alice,&nbsp;Franc Emmanuelle,&nbsp;Gatoussi Fatma,&nbsp;Ben Slimane Abir,&nbsp;Gasmi Mohamed,&nbsp;Braud Isabelle,&nbsp;Gaillardet Jérôme","doi":"10.1002/hyp.70682","DOIUrl":"https://doi.org/10.1002/hyp.70682","url":null,"abstract":"<div>\u0000 \u0000 <p>Understanding the frequency and magnitude of extreme hydrological events is crucial for assessing flood risk. However, long-term monitoring data are lacking to better capture flood variability with past and present climate changes; thus, sedimentary archives are needed to extend such data back in time. In this study, we use lacustrine sediment archives from the Kamech reservoir (Cap Bon, Tunisia), located at the outlet of a semiarid rural catchment characterised by intermittent streamflow and severe erosion. The catchment has been instrumentally monitored since the dam reservoir was built in 1994 at its outlet. Monitoring includes high-resolution measurements of rainfall and stream flow since 1994, and of sediment flux since 2006. Here, the main objective is to compare sedimentary records with in situ hydro-erosive measurements to assess how well sedimentary deposits can be used to estimate the streamflow and erosive intensity of past floods. In 2022, sediment cores up to 3 m deep were collected from the reservoir, capturing the full post-construction infill history since 1994. The sediment sequence is varved allowing for annual to sub-annual resolution. Using a combination of sedimentological (grain size, hyperspectral imaging) and geochemical (XRF core scanning) analyses, along with short-lived radionuclide dating, we identified 35 distinct flood layers corresponding to major events over the past 24 years. We demonstrate that the thickness of flood layers is closely correlated with the sediment flux measured in the catchment. Furthermore, we show that the maximum grain size (<i>D</i>₉₀) in flood layers is strongly correlated with the maximum 30 min flood discharge (<i>Q</i>_30max) and daily precipitation amounts. Our results highlight the potential of lake sediments to quantitatively reconstruct flood intensity chronicles, complementing modern monitoring in the critical zone and helping to assess the long-term impact of climate variability on flood and erosion regimes.</p>\u0000 </div>","PeriodicalId":13189,"journal":{"name":"Hydrological Processes","volume":"40 9","pages":""},"PeriodicalIF":3.1,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148942266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 Controls on Nitrate Release at the Meltwater-Frozen Soil Interface in Seasonally Frozen Croplands","authors":"Jifeng Zhang,&nbsp;Jingwei Wu,&nbsp;Jieying Liu,&nbsp;Qiang Zhao","doi":"10.1002/hyp.70671","DOIUrl":"https://doi.org/10.1002/hyp.70671","url":null,"abstract":"<div>\u0000 \u0000 <p>The presence of low-permeability frozen soil layer forces meltwater to flow primarily laterally within an extremely thin saturated zone at the soil surface. However, the dynamics of solute release at this interface and the underlying driving mechanisms remain poorly understood. In this study, controlled laboratory experiments were conducted using a self-designed, unidirectional freezing apparatus to investigate nitrate transport within the thin saturated layer at the meltwater-frozen soil interface during early spring thaw. Results indicate that nitrogen extraction efficiency at this interface is not constant but is significantly governed by inflow conditions; specifically, it exhibits a significant positive correlation with the ionic concentration of the meltwater inflow and a negative correlation with flow rate. To account for the observed concentration effects, the Electric Double Layer theory was introduced into the analysis. Analysis reveals that high NO₃⁻-N concentration compresses the electrical double layer thickness on soil colloid surfaces, generating an electrostatic shielding effect that microscopically accelerates nitrogen desorption from the soil surface. Incorporating these key driving factors, a CSTR model coupled with reversible first-order kinetics was developed. This model effectively integrates the effects of unsteady flow and NO₃⁻-N concentration and successfully reproduces the non-equilibrium solute transport processes at the meltwater-frozen soil interface with high simulation accuracy (<i>R</i>² &gt; 0.85). This study improves the understanding of the dominant factors and adsorption–desorption mechanisms governing solute release in the thin saturated layer at the meltwater-frozen soil interface, and provides a process-based basis for modelling and risk assessment of snowmelt-driven non-point source pollution in cold-region agricultural systems.</p>\u0000 </div>","PeriodicalId":13189,"journal":{"name":"Hydrological Processes","volume":"40 9","pages":""},"PeriodicalIF":3.1,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148860109","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Estimating Snowmelt Infiltration by Numerical Integration of Soil Moisture Data","authors":"Louis M. Benson,&nbsp;David C. Mays","doi":"10.1002/hyp.70669","DOIUrl":"https://doi.org/10.1002/hyp.70669","url":null,"abstract":"<div>\u0000 \u0000 <p>Predicting snowmelt infiltration into soils is critical for water supply management, which has prompted a call for additional research on infiltration beneath snowpack. This study estimates snowmelt infiltration, through a first-order diagnostic process, using soil moisture data available, for example, through snowpack telemetry (SNOTEL) in the USA, and the global High Resolution Daily Multilayer Soil Moisture Dataset. Given soil moisture versus time at various depths, depth-integrated moisture content provides total water volume versus time. Snowmelt infiltration is estimated based on the assumption that increases in total water volume result from infiltration at the soil surface. This study details the codes written for numerical integration of soil moisture data, then documents model verification using infiltration data simulated by HYDRUS-1D, model validation using infiltration measured in a field study, and model application with three North American case studies across a range of elevations. For these case studies, an estimated 12%–36% of snow water equivalent (SWE) infiltrated to soil moisture. Codes and data are available through the online repository HydroShare.</p>\u0000 </div>","PeriodicalId":13189,"journal":{"name":"Hydrological Processes","volume":"40 9","pages":""},"PeriodicalIF":3.1,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148860021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Direct Rapid Recharge Controls the Hydrological Response in a Peri-Urban Mountainous Tropical Catchment","authors":"Leonardo Mena-Rivera,&nbsp;Germain Esquivel-Hernández,&nbsp;Mario Villalobos-Forbes,&nbsp;Rolando Sánchez-Gutiérrez,&nbsp;Ricardo Sánchez-Murillo,&nbsp;Laura Castro-Chacón,&nbsp;Luis Rojas-Jiménez,&nbsp;Astrid Harjung","doi":"10.1002/hyp.70685","DOIUrl":"https://doi.org/10.1002/hyp.70685","url":null,"abstract":"<div>\u0000 \u0000 <p>In the wet tropics, the seasonal changes in rainfall amounts are altering catchment storage and, consequently, groundwater-to-surface water connectivity. However, estimations of water source contributions to streamflow remain poorly constrained across mountainous headwater catchments. Here, we use stable isotopes (δ¹⁸O and δ²H), ²²²Rn activity and electrical conductivity (EC) to characterise the hydrological responses in the northern mountainous region of the Central Valley, Costa Rica. Temporal trends revealed a clear response in groundwater–surface water connectivity to rainfall inputs. Streamflow transitioned from being dominated mainly by groundwater during the dry season to a greater contribution of subsurface flow during the wet season. We found that direct rapid recharge regulates this hydrological connectivity during the rainiest periods, as demonstrated by increased ²²²Rn activity in both springs and streams. Using a mass balance approach, we estimated monthly groundwater contributions to streamflow using ²²²Rn activity (5.9%–63.1%) and EC (37.2%–84.0%). A Bayesian endmember mixing model yielded similar mean groundwater contributions compared to the mass balance approach depending on tracer selection (EC–²²²Rn: 56.2% ± 12.7%, δ¹⁸O–²²²Rn: 51.1% ± 11.6% and δ¹⁸O–EC: 89.2% ± 5.2%). Our findings are useful for future assessments of the impact of climate change in rainfall amount and seasonality on groundwater recharge and streamflow generation in tropical mountainous catchments.</p>\u0000 </div>","PeriodicalId":13189,"journal":{"name":"Hydrological Processes","volume":"40 9","pages":""},"PeriodicalIF":3.1,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148860024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Snowmelt-Associated Inundation Dynamics in a Semi-Arid Floodplain: Evidence From Multi-Temporal Sentinel-1 Observations in the Aras Basin, Eastern Türkiye","authors":"Mehmet Ali Çelik,&nbsp;Mehmet Ali Aycan","doi":"10.1002/hyp.70679","DOIUrl":"https://doi.org/10.1002/hyp.70679","url":null,"abstract":"<div>\u0000 \u0000 <p>Flood generation in semi-arid basins surrounded by seasonally snow-covered mountains cannot be explained by rainfall alone, yet the relative contributions of snowmelt and rainfall to observed inundation remain insufficiently quantified in eastern Anatolia. This study combines 80 Sentinel-1 Synthetic Aperture Radar (SAR) scenes acquired between March and June from 2017 to 2025, processed with the HydroSAR surface-water mapping workflow, with ERA5-Land hydro-climatic variables and terrain data to examine the spatial and temporal patterns of inundation along the Aras River floodplain in the Iğdır–Aralık sector of eastern Türkiye. SAR-derived detections were predominantly low-frequency but spatially widespread, reaching 115.2 km² at the ≥ 1-observation threshold while surface water detected on at least 50 observation dates covered approximately 1.2 km². Detections were concentrated in low-lying terrain, with more than 99% in the 800–900 m elevation range and approximately 82% within 0–2 m of Height Above Nearest Drainage. The largest single-date extents occurred in 2020 (70.7 km²) and 2022 (68.0 km²), both in March. Across the analysed acquisitions, snowmelt showed a moderate positive association with detected extent (<i>r</i> = 0.54, <i>p</i> &lt; 0.001) and snow depth a comparable association (<i>r</i> = 0.49), whereas rainfall showed a weak, non-significant relationship. Of five independently documented flood events, only one coincided with an elevated SAR-derived observation, reflecting the approximately 12-day revisit interval, short event durations and small event footprints. Inundation in this floodplain was therefore more closely associated with seasonal snow accumulation and melting than with rainfall during the observation period, and satellite-derived surface-water inventories require independent hydrological observations before they can be interpreted as flood records.</p>\u0000 </div>","PeriodicalId":13189,"journal":{"name":"Hydrological Processes","volume":"40 8","pages":""},"PeriodicalIF":3.1,"publicationDate":"2026-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148848837","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}