Hydrological Processes最新文献

{"title":"Overcoming Challenges in Mapping Hydrography and Heterogeneity in Urban Landscapes","authors":"Kristina G. Hopkins,&nbsp;Rebecca L. Hale,&nbsp;Krista A. Capps,&nbsp;John S. Kominoski,&nbsp;Jennifer L. Morse,&nbsp;Allison H. Roy,&nbsp;Andrew Blinn,&nbsp;Shuo Chen,&nbsp;Liz Ortiz Muñoz,&nbsp;Annika Quick,&nbsp;Jacob Rudolph","doi":"10.1002/hyp.70221","DOIUrl":"https://doi.org/10.1002/hyp.70221","url":null,"abstract":"<div>\u0000 \u0000 <p>Understanding how water moves through a watershed is one of the most fundamental yet often complicated aspects of hydrology, especially in urban areas. Urban infrastructure and water management alter natural hydrological pathways in developed watersheds, which can violate assumptions of a watershed approach to ecosystem science. We focus on two aspects of urban landscapes that often create challenges to model watershed processes within and among urban areas: (1) accurate delineation of urban flow paths and (2) consistent characterisation of the urban landscape within and among cities. Here, we describe these challenges and identify how certain components of these challenges can be addressed, highlighting examples and lessons learned in a project that is assessing scales and drivers of variability in dissolved organic carbon across five urban centres in the United States. Our goal is to facilitate a dialogue that will advance the applications of watershed approaches in urban ecosystem science by recognising and addressing these challenges. Our examples focus on the United States but could be applicable to similar urban challenges in other locations globally.</p>\u0000 </div>","PeriodicalId":13189,"journal":{"name":"Hydrological Processes","volume":"39 8","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144811060","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 Modelling of Flow and Nitrate Load Using SWAT+","authors":"Mahesh R. Tapas,&nbsp;Thanh-Nhan-Duc Tran,&nbsp;Randall Etheridge,&nbsp;Venkataraman Lakshmi","doi":"10.1002/hyp.70220","DOIUrl":"https://doi.org/10.1002/hyp.70220","url":null,"abstract":"&lt;p&gt;Climate change is increasingly threatening watersheds worldwide (Harris et al. &lt;span&gt;2024&lt;/span&gt;; Mankar et al. &lt;span&gt;2020&lt;/span&gt;; Tran and Lakshmi &lt;span&gt;2024a&lt;/span&gt;; Tran et al. &lt;span&gt;2024&lt;/span&gt;; Yin et al. &lt;span&gt;2024&lt;/span&gt;), leading to prolonged droughts (Sharma et al. &lt;span&gt;2022&lt;/span&gt;; Tapas, Kumar, et al. &lt;span&gt;2022&lt;/span&gt;; Do et al. &lt;span&gt;2024&lt;/span&gt;) and more frequent floods (Prabha and Tapas &lt;span&gt;2020&lt;/span&gt;) that endanger ecosystem health (Mishra et al. &lt;span&gt;2023&lt;/span&gt;). Hydrological modelling has become an essential tool for assessing the severity of these impacts (Tapas et al. &lt;span&gt;2024c&lt;/span&gt;; Murumkar et al. &lt;span&gt;2025&lt;/span&gt;; Marshall et al. &lt;span&gt;2025a&lt;/span&gt;, &lt;span&gt;2025b&lt;/span&gt;; Tran and Lakshmi &lt;span&gt;2024b&lt;/span&gt;). Over the past decade, technological advancements have significantly enhanced hydrological modelling capabilities (Brookfield et al. &lt;span&gt;2023&lt;/span&gt;; Jehanzaib et al. &lt;span&gt;2022&lt;/span&gt;). The Soil and Water Assessment Tool (SWAT) has evolved into SWAT+, offering a more user-friendly environment and improved process representations (SWAT+ &lt;span&gt;2020&lt;/span&gt;; Tran et al. &lt;span&gt;2023&lt;/span&gt;). While recent studies have utilised SWAT+, there remains considerable potential to further explore its effectiveness in nutrient modelling.&lt;/p&gt;&lt;p&gt;In this study, we employed the SWAT+ model for the Tar-Pamlico River Basin, developed by Tapas (&lt;span&gt;2024a&lt;/span&gt;, &lt;span&gt;2024b&lt;/span&gt;), to provide a detailed depiction of flow and nitrate distributions across the basin (Tapas et al. &lt;span&gt;2024c&lt;/span&gt;). The model was constructed using an array of datasets, including the Digital Elevation Model (DEM), observed flow data from the United States Geological Survey (USGS), land cover data from the National Land Cover Database (NLCD), soil data from the Soil Survey Geographic Database (SSURGO), weather data from the Global Precipitation Measurement Integrated Multi-satellite Retrievals for GPM (GPM IMERG), and water quality data from the North Carolina Department of Environmental Quality (NCDEQ) (Tapas, Etheridge, et al. &lt;span&gt;2022&lt;/span&gt;; Tapas et al. &lt;span&gt;2023&lt;/span&gt;, Tapas &lt;span&gt;2024b&lt;/span&gt;, Tapas, Etheridge, et al. &lt;span&gt;2025&lt;/span&gt;, Tapas, Howard, et al. &lt;span&gt;2025&lt;/span&gt;).&lt;/p&gt;&lt;p&gt;Tapas et al. (&lt;span&gt;2024&lt;/span&gt;) optimised the SWAT+ model for monthly flow and monthly nitrate load at Washington, North Carolina, using a two-year warm-up period (January 2001 to December 2003), a calibration period from January 2003 to December 2011, and a validation period from January 2012 to December 2019. The model was also soft-calibrated for annual average hydrological response unit (HRU) scale flow, nitrate loss, yield, and denitrification. Lastly, the model was cross-validated for monthly flow at two additional upstream locations in the watershed (Greenville and Tarboro, NC) (Video 1).&lt;/p&gt;&lt;p&gt;To effectively communicate the model results, dynamic animations illustrate the spatiotemporal dynamics of flow and nitrate load throughout the Tar-Pamlico ","PeriodicalId":13189,"journal":{"name":"Hydrological Processes","volume":"39 8","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hyp.70220","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144811062","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":"Eroded Sediment of Silt Dam Influenced by Spatial Distribution of Terraces in Watershed in the Loess Hilly–Gully Region (LHGR), China","authors":"Zhe Gao,&nbsp;Gen'guang Zhang,&nbsp;Hongke Hao,&nbsp;Hong Zhang,&nbsp;Bo Yang,&nbsp;Hao Jia,&nbsp;Henghui Fan,&nbsp;Jian'en Gao","doi":"10.1002/hyp.70156","DOIUrl":"https://doi.org/10.1002/hyp.70156","url":null,"abstract":"<div>\u0000 \u0000 <p>A outstanding issues in the management of Loess Plateau, the fragile ecological hydraulic erosion area, is that many silt dams were rapid abandonment or the dam land couldn't be formed because of the abundance or scarcity of sediment resulted from the uncoordinated arrangement of vegetation, terraced fields and silt dams. By constructing a 3D solid model of vegetation-terraced field-silt dam-small watershed of rainfall–runoff erosion, the coordinated relationships of water and sediment were studied under different terraced fields, vegetation coverage and rainstorm levels. The some calculation equations were obtained and vertified for the sedimentation drop ratio and relative sedimentation morphology parameters of silt dams with the spatial variation of terraced fields. It was found that the relative siltation morphological parameters (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>C</mi>\u0000 <mrow>\u0000 <mi>Rt</mi>\u0000 <mo>~</mo>\u0000 <mi>α</mi>\u0000 </mrow>\u0000 </msub>\u0000 </mrow>\u0000 <annotation>$$ {C}_{Rtsim alpha } $$</annotation>\u0000 </semantics></math>) of silt dams before and after watershed control had a good relationship with silt dam silt blocking modulus (<i>M</i>_<i>s</i>), and could reflect the coordinated relationship between vegetation-terraced fields and silt dams. When <i>M</i>_<i>s</i> ≤ 1000 t/(km² a), <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>C</mi>\u0000 <mrow>\u0000 <mi>Rt</mi>\u0000 <mo>~</mo>\u0000 <mi>α</mi>\u0000 </mrow>\u0000 </msub>\u0000 </mrow>\u0000 <annotation>$$ {C}_{Rtsim alpha } $$</annotation>\u0000 </semantics></math> and <i>M</i>_<i>s</i> is a power function relationship, which reflected that the terraces were arranged in the upper reaches of the watershed, the siltation of the silt dam was small and the siltation morphology was similar to belt or delta sedimentation. When <i>M</i>_<i>s</i> &gt; 1000 t/(km² a), the <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>C</mi>\u0000 <mrow>\u0000 <mi>Rt</mi>\u0000 <mo>~</mo>\u0000 <mi>α</mi>\u0000 </mrow>\u0000 </msub>\u0000 </mrow>\u0000 <annotation>$$ {C}_{Rtsim alpha } $$</annotation>\u0000 </semantics></math> was close to the constant, indicating that the sedimentation was serious and the morphology was similar to that of vertebral body. <i>M</i>_<i>s</i> = 1000 t/(km² a) is the t","PeriodicalId":13189,"journal":{"name":"Hydrological Processes","volume":"39 8","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144811059","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":"Strategies to Address Risks to Groundwater Dependent Ecosystems","authors":"Laurel Saito,&nbsp;Sarah Byer,&nbsp;Liz Munn,&nbsp;Kevin Badik,&nbsp;Louis Provencher,&nbsp;Dan J. McEvoy,&nbsp;Melissa M. Rohde","doi":"10.1002/hyp.70229","DOIUrl":"https://doi.org/10.1002/hyp.70229","url":null,"abstract":"<p>Groundwater, the largest source of freshwater on Earth, is increasingly relied upon as freshwater demands increase for humans and ecosystems, especially under a warming climate. Groundwater is particularly critical in meeting freshwater needs in arid regions that have less reliable surface water sources. We examined risk factors that can affect groundwater-dependent ecosystems (GDEs) across Nevada, the driest state in the United States. The risk factors included groundwater withdrawals, climate, ungulates, non-native species, urbanisation, and surface water diversions. We found that almost 40% of the thousands of wells analysed had significantly declining groundwater levels. In addition, the entire state is projected to be more droughty in the future, which will exacerbate other stressors and threats. We also present 10 strategies in four categories (science and monitoring, policy, management, and education) that collectively can address these stressors and threats. These strategies can be used to prioritise work on GDEs to improve their resiliency to disturbance and climate change not only in Nevada, but around the world where similar stressors and threats are being faced.</p>","PeriodicalId":13189,"journal":{"name":"Hydrological Processes","volume":"39 8","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hyp.70229","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144782537","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":"Characterising Tropical Peatland Hydrological Response With Satellite-Based Rainfall: A Case Study in Brunei","authors":"Sebastian Apers,&nbsp;Alexander R. Cobb,&nbsp;Gabriëlle J. M. De Lannoy,&nbsp;Michel Bechtold","doi":"10.1002/hyp.70209","DOIUrl":"https://doi.org/10.1002/hyp.70209","url":null,"abstract":"<p>Peat hydraulic properties play a crucial role in regulating tropical peatland hydrology and are therefore critical parameters in peatland-specific hydrological models. Peat hydraulic and discharge parameters can be estimated by analysing time series of in situ water levels and precipitation, along with topographic data. However, in situ precipitation data are typically not available near water level measurements in densely vegetated and remote tropical peatlands. Gridded satellite precipitation products provide an alternative, but are coarse and highly uncertain. Here, we present a method for the hydrological parameterisation of water level dynamics using satellite-based precipitation, while accounting for representativeness errors in the precipitation data. First, we adapt the water level rise and recession analysis from Cobb and Harvey (<i>Water Resources Research</i>, 55 (11), 9351–9377; 2019) for use with Integrated Multi-satellitE Retrievals for Global Precipitation Measurement (IMERG) precipitation estimates. Applied to a tropical peatland in Brunei, the adapted rise and recession analysis reduces: (i) the average error in water level rise in response to rainfall and (ii) the average daily recession overestimation. In addition, we quantify the sensitivity of our adapted rise analysis to precipitation errors using an ensemble of precipitation time series with multiplicative errors. Second, the adapted master rise and recession curves are used to fit soil hydraulic and discharge function parameters within the peatland-specific module of the NASA Catchment Land Surface Model. Our analysis enables the retrieval of accurate hydrological parameters for our case study using IMERG data, and can be transferred to other peatlands and satellite-based precipitation products. It also highlights the importance in tropical peatland hydrology of cloud-scale forcing that is not resolved in existing satellite-based precipitation products.</p>","PeriodicalId":13189,"journal":{"name":"Hydrological Processes","volume":"39 8","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hyp.70209","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144773649","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":"A Data-Driven Analysis of Streamflow Pattern Recognition and Seasonal Transition Changes","authors":"Chun-Ta Wen,&nbsp;Yu-Ju Hung,&nbsp;Gene Jiing-Yun You,&nbsp;Yu-Jia Chiu","doi":"10.1002/hyp.70226","DOIUrl":"https://doi.org/10.1002/hyp.70226","url":null,"abstract":"<div>\u0000 \u0000 <p>Seasonal streamflow transitions play a critical role in water resource management, particularly in supporting flood prevention and drought mitigation. However, understanding how these transitions shift under climate variability remains limited, especially when conventional methods rely on fixed-calendar metrics or station-based trends. This study introduces a time series clustering framework that integrates dynamic time warping (DTW) and hierarchical clustering analysis (HCA) with change-point detection and trend decomposition to capture evolving intra-annual flow patterns and seasonal transitions. By analysing transition timing within each flow pattern group, the approach moves beyond static classification to uncover climate sensitivity that is often masked in basin-aggregated results. Applied to long-term inflow records from four major reservoirs in Taiwan, the analysis reveals both spatial and pattern-conditioned changes in wet-season onset. At Shihmen Reservoir, the station-based trend suggests a general advancement in transition timing. However, when hydrologic years are grouped by flow patterns influenced by climate drivers, some clusters indicate delays linked to late-season typhoons, while others show earlier transitions associated with frontal rainfall. This contrast illustrates how aggregated trends can obscure flow-type-specific responses to climate variability. The proposed framework offers a flexible and transferable means of diagnosing intra-annual hydrological variability. It provides practical tools for adaptive water management and planning in regions facing intensifying seasonal uncertainty and hydrometeorological extremes.</p>\u0000 </div>","PeriodicalId":13189,"journal":{"name":"Hydrological Processes","volume":"39 8","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144773648","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":"Interplay of Crop Cover and Tillage on Runoff and Sediment Dynamics Under Simulated Rainfall: A Case Study in the Black Soil Region of Northeast China","authors":"Xiaoqiong Chen,&nbsp;Zhuodong Zhang,&nbsp;Bo Chen,&nbsp;Yintong Zhang,&nbsp;Peiting He","doi":"10.1002/hyp.70231","DOIUrl":"https://doi.org/10.1002/hyp.70231","url":null,"abstract":"<div>\u0000 \u0000 <p>We conducted 24 in situ simulated rainfall experiments featuring variable intensity over nine cropland plots subject to three tillage practices in the black soil region of Northeast China. The experimental setup involved eight scenarios, incorporating combinations of complete and zero crop cover, hourly rainfall amounts of 45 and 65 mm, and dry and wet antecedent soil moisture conditions. Our experiment shows that, compared to up and down the slope tillage (UDST) plots: (1) In the analysis aggregating multiple rainfall-runoff event data, contour tillage (CT) plots showed a notable increase in the reduction rates of total runoff, peak discharge and peak sediment concentration as crop cover increased from zero to complete. Specifically, reductions rose from 18%, 6% and 80% to 67%, 56% and 85%, respectively. In contrast, flat tillage (FT) plots showed a transition in total runoff and peak discharge from slightly more to slightly less, with a notable increase in peak sediment concentration reduction from 28% to 45% and (2) Analyses of individual events indicate that the ratio of total runoff, peak discharge and peak sediment concentration over CT plots compared to UDST plots range approximately in [6%, 100%], [6%, 100%] and [10%, 30%], these ratios over FT plots range in [60%, 130%], [60%, 130%] and [30%, 80%]. These data suggest that increased crop cover tends to amplify the total runoff and peak discharge reduction effects of tillage practices, and the runoff and sediment reduction rates vary notably across individual rainfall-runoff events. Additionally, both the magnitudes of amplification and variability depend on specific tillage practices employed. Notably, changes in crop cover have a more substantial impact on the runoff and sediment reduction effectiveness than variations in rainfall intensity and antecedent soil moisture. The necessity of employing in situ simulated rainfall experiments were also discussed. These findings highlight the interplay of crop cover and tillage on cropland runoff and sediment dynamics, offering valuable insights into improving soil and water conservation strategies.</p>\u0000 </div>","PeriodicalId":13189,"journal":{"name":"Hydrological Processes","volume":"39 8","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144767883","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":"Understanding Complex Processes of Flood Inundation in a Regulated Coastal Lowland River: A Modelling Framework Integrating Hydrological, Hydraulic, Tidal and Geomorphic Data","authors":"Zafar Beg,&nbsp;Kumar Gaurav,&nbsp;Gaurav Kailash Sonkar,&nbsp;Vikrant Jain","doi":"10.1002/hyp.70227","DOIUrl":"https://doi.org/10.1002/hyp.70227","url":null,"abstract":"<div>\u0000 \u0000 <p>Inundation dynamics in lowland rivers are an outcome of a complex interaction between hydrologic and geomorphic factors. The co-occurrence of river flow and tidal surge in coastal regions further complicates these interactions. The extent to which these factors mediate inundation mechanisms in regulated lowland river reaches remains challenging and has been poorly understood. This study presents a novel framework that examines the combined effect of flood drivers (riverine and high tide) and geomorphic factors in determining the inundation mechanism along the Lower Tapi Basin (LTB) in western India through an integration of hydrological, tidal, hydrodynamic, and geomorphic datasets. Using variable infiltration capacity (VIC) and Hydrologic Engineering Center River Analysis System (2D HEC-RAS) with geomorphic characteristics of river channels, we explore how spatial inundation dynamics vary across different valley settings under different flood return periods. Our integrated modelling framework accurately simulates daily streamflow and flood inundation. Incorporation of multidisciplinary data through the integrated modelling framework has advanced our understanding of flood inundation dynamics in lowland rivers. We have further shown that the model uncertainty can be reduced by incorporating field data, bathymetric measurements and rule curve of reservoir operation in the model domain. Although this modelling framework has been developed on a specific lowland reaches of the Tapi River, it can be further extended to any lowland rivers in similar settings. Such multidisciplinary models will help to analyse river response to future projected climate and sea level change.</p>\u0000 </div>","PeriodicalId":13189,"journal":{"name":"Hydrological Processes","volume":"39 8","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144758531","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":"Evaluating Trends Using Total Impervious Cover as a Metric for Degree of Urbanisation","authors":"Laura Toran,&nbsp;Daniel J. Bain,&nbsp;Kristina Hopkins,&nbsp;Joel Moore,&nbsp;Emily O'Donnell","doi":"10.1002/hyp.70219","DOIUrl":"https://doi.org/10.1002/hyp.70219","url":null,"abstract":"<div>\u0000 \u0000 <p>Impervious cover (IC) is a common metric for assessing the degree of urbanisation in watersheds. However, there are different methods for determining IC, and use of IC correlation with urban watershed response to hydrologic and geochemical inputs can be strongly influenced by the end members (IC below 10% and above 40%). The resolution of the imagery (e.g., 1 m vs. 30 m) used to measure IC can influence the estimate of IC, with differences up to 15% observed between these two resolutions for 21 watersheds along the east coast of the United States. The differences are greatest in the middle range between 10% and 40% IC. When using IC for correlation with urban watershed responses such as discharge flashiness or median solute concentrations, fits with R² between 0.4 and 0.78 were obtained when including end members of IC from 0% to 50%. However, when trying to distinguish behaviour between urban watersheds that fall in the middle ranges of IC, these same parameters do not correlate well with IC. Correlations fail significance tests, can switch direction, and fall below an R² of 0.1 without the end members of very low or very high IC. Because of improved accuracy, the finest resolution is preferred when available, and mixing IC estimation methods should be avoided. Furthermore, using regressions that include end members may not contribute to differentiating how IC in the 10%–40% range impacts hydrologic and geochemical responses in urban watersheds. Understanding this middle range of IC is important for comparing urban and suburban watersheds or planning watershed development to minimise impacts.</p>\u0000 </div>","PeriodicalId":13189,"journal":{"name":"Hydrological Processes","volume":"39 8","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144758533","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":"Runoff Generation Mechanism of Small Forest Watersheds in Humid Regions of China Under Single Rainstorm Conditions","authors":"Fei Sheng,&nbsp;Yanyan Wang,&nbsp;Xiaofei Nie,&nbsp;Shiyu Liu,&nbsp;Haijin Zheng,&nbsp;Guangjie Chen,&nbsp;Changming Zhou,&nbsp;Tingxin Yi,&nbsp;Zhao Liu","doi":"10.1002/hyp.70230","DOIUrl":"https://doi.org/10.1002/hyp.70230","url":null,"abstract":"<div>\u0000 \u0000 <p>Runoff generation is the production of various runoff components and is a fundamental aspect of the hydrological cycle. Investigating the evolution mechanism and laws governing the formation process of watershed runoff from the perspective of runoff generation mechanisms has consistently been a focal point and challenge within the field of hydrology. However, the variation in the mechanisms of runoff generation under single rainstorm conditions has not been fully elucidated, particularly in the humid regions of China. In the present study, we focus on the Pengchongjian small watershed in Southeastern China, where the average annual precipitation is 1589 mm. Based on long-term hydrometeorological data, precipitation and runoff characteristics during single rainstorm conditions in the watershed were analysed. Alterations in the runoff generation mechanism were investigated in conjunction with the underlying surface characteristics. The findings revealed that in comparison to the baseline period (1983–2003), there was a 4.6% reduction in average rainfall amount and a 23.8% decrease in average runoff depth during the changing period (2004–2017). Additionally, it was observed that runoff depth exhibited more pronounced fluctuations, with a much higher variation coefficient than rainfall amount. Rainfall amount remained the primary factor influencing changes in runoff depth across different periods. However, its relative contribution decreased during the changing period, while the impact of non-precipitation factors increased during this period. There was an extremely significant upward trend in the normalised difference vegetation index of the watershed, and the forest coverage increased from 80% to 98%. The water conservation capacity of the main stands (Chinese fir forests) were higher than other forest types. Under the conditions of a single rainstorm, the predominant runoff generation pattern observed during various periods in the watershed was saturation-excess runoff, indicating a high soil infiltration rate. The proportion of the runoff generation patterns showed a significant change. During the baseline period, the proportion of saturation-excess runoff was 45.3%, which increased to 52.9% in the changing period. In contrast, the infiltration-excess runoff decreased from 36.8% to 32.9%. Additionally, the proportion of mixed runoff decreased from 17.9% to 14.2%. Meanwhile, the probability of interflow and groundwater flow generation increased, indicating an enhancement in the regulation and storage effects on watershed runoff. The findings of this research provide a scientific basis for mitigating and controlling flood disasters, optimising the allocation of water resources and evaluating the hydrological effects of the watersheds.</p>\u0000 </div>","PeriodicalId":13189,"journal":{"name":"Hydrological Processes","volume":"39 8","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144758499","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}