Catena最新文献

{"title":"Tracking nitrate sources and transport pathways in riparian wetlands using a multi-tracer approach combined with a Bayesian mixing model","authors":"Zhendong Hong ,&nbsp;Pengwei Qiu ,&nbsp;Yu Xi ,&nbsp;Qinghe Zhao ,&nbsp;Shengyan Ding","doi":"10.1016/j.catena.2025.109201","DOIUrl":"10.1016/j.catena.2025.109201","url":null,"abstract":"<div><div>Identifying nitrate (NO₃⁻) sources and key transport pathways is essential to manage diffuse NO₃⁻ pollution, particularly in riparian wetlands where nitrate pollution is a major contribution to eutrophication. In this study, we used multiple tracers to assess the contribution of multiple NO₃⁻ sources and transport pathways in the riparian wetlands along the lower Yellow River during four hydrological seasons. The results revealed that NO₃⁻ concentrations in approximately 12.2 % riparian wetland water along the lower Yellow River were higher than the Chinese government and WHO allowed threshold (10 mg/L), particularly in wetlands outside the dykes during high flow seasons. The signature of hydrochemical parameters and stable isotopes (δ¹⁵N-NO₃⁻, δ¹⁸O-NO₃⁻ and δ¹⁸O-H₂O) values illustrated multiple sources recharge NO₃⁻ levels in riparian wetland water, rather than biogeochemical processes. A Bayesian mixing model based on dual nitrate isotope values further revealed that chemical fertilizer (35 %), soil organic nitrogen (33 %), and manure/sewage (26 %) served as the main NO₃^– source recharging riparian wetlands water. Of the main nitrate transport pathways, groundwater (34 %), the Yellow River (33 %), and canal water (28 %) contributed more to riparian wetlands water pollution that did atmospheric deposition (precipitation). However, both source and the relative importance of certain transport pathways of NO₃⁻ varied both spatially and temporally. These results are critical for better informing the management and restoration of riparian wetlands.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"257 ","pages":"Article 109201"},"PeriodicalIF":5.4,"publicationDate":"2025-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144168305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Divergent effects of soil organic matter and carbonate on soil aggregation and structure in arid regions","authors":"Zhufeng Wang ,&nbsp;Yugang Wang ,&nbsp;Dengchun Xing ,&nbsp;Rota Wagai ,&nbsp;Jinsen Zheng ,&nbsp;Haoyuan Zhang ,&nbsp;Bowen Fan ,&nbsp;Wenting Feng","doi":"10.1016/j.catena.2025.109196","DOIUrl":"10.1016/j.catena.2025.109196","url":null,"abstract":"<div><div>Understanding how calcium carbonate (CaCO₃) mediates soil aggregation and structure has important implications for soil organic carbon sequestration. Despite its prevalence in arid regions, the impact of CaCO₃ on soil structure remains frequently overlooked and poorly understood. This study aimed to <em>i</em>) explore the relationships between organic and inorganic binding agents and soil aggregation across macro- to micro-scales, as indicated by mean weighted diameter (MWD), specific surface area (SSA), and porosity, and <em>ii</em>) assess the changes in SSA and porosity before and after CaCO₃ removal in bulk soil and aggregate fractions. Conducting research along an elevation gradient in the Tianshan mountain, we evaluated soil aggregation indicators alongside organic binding agents (<em>i.e</em>., soil organic matter, SOM) and inorganic agents (<em>i.e</em>., CaCO₃, exchangeable Ca, iron/alumina (hydro)oxides, and silt-clay). Our findings indicate that SOM primarily contributes to MWD, promoting macro-aggregate (&gt;250 μm) formation. The influence of SOM on SSA and total pore volume (TPV) varies with elevation sites, underscoring a SOM content-dependent relationship. Conversely, CaCO₃ and exchangeable Ca form micro-aggregates in calcareous soils. Notably, CaCO₃ exhibited a negative correlation with SSA and TPV, while its removal led to increased SSA and TPV in bulk soil and &lt;53 μm aggregates. This research highlights the divergent roles of SOM and carbonate in soil aggregation and their interactions in arid environments, emphasizing the importance of managing CaCO₃ levels to maintain soil structure and organic carbon sequestration potential.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"257 ","pages":"Article 109196"},"PeriodicalIF":5.4,"publicationDate":"2025-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144168306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Temporal and geographic extrapolation of soil moisture using machine learning algorithms","authors":"Efthymios Chrysanthopoulos,&nbsp;Andreas Kallioras","doi":"10.1016/j.catena.2025.109156","DOIUrl":"10.1016/j.catena.2025.109156","url":null,"abstract":"<div><div>The inherent characteristic of machine learning algorithms to extrapolate when the convex hull is expanded with new unseen instances, can be exploited in soil moisture prediction, concerning temporal and geographic extrapolation. This study describes the implementation of a machine learning framework, evaluating the performance of both individuals (Support Vector Regressor) and ensemble algorithms (Random Forests and Voting Regressor) in temporal and geographic extrapolation of soil moisture beyond the feature space of the calibration data. While most studies focus on temporal extrapolation and spatial interpolation of soil moisture in the framework of calibration stations, this study provides important insights on soil moisture prediction in distinct locations of a catchment where target variables are available, using pre-calibrated models at an individual station. The approach is originally based on the calibration of each machine learning algorithm with the soil moisture data from every agro-meteorological station of the monitoring networks and the evaluation both in temporal extrapolation context with future data of the same station and in geographic extrapolation with data concerning the location of rest of the stations.Overall the results indicate that in the context of temporal extrapolation the algorithms achieve adequate accuracy with the performance metrics to achieve values R² &gt; 0.75, RMSE &lt; 0.042 cm³cm⁻³ and MAE &lt; 0.001 cm³cm⁻³, while in the context of geographic extrapolation algorithms trained using soil moisture data from a distinct agro-meteorological station are capable of predicting soil moisture with enhanced efficiency when applied to previously unseen datasets. The results of this research indicate the applicability of the framework in unmonitored sites.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"257 ","pages":"Article 109156"},"PeriodicalIF":5.4,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144146845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Landscape Disturbance Effects of the Large-scale Water Storage Activity in the Baihetan Reservoir on the Jinsha River, China","authors":"Zhenkui Gu ,&nbsp;Chuangchuang Yao ,&nbsp;Xin Yao ,&nbsp;Xuchao Zhu ,&nbsp;Renjiang Li","doi":"10.1016/j.catena.2025.109197","DOIUrl":"10.1016/j.catena.2025.109197","url":null,"abstract":"<div><div>Constructing large hydroelectric power stations in canyon areas is widely accepted as a solution to meet energy demands. However, large-scale water storage elevates water levels, shifts the water-land boundary, increases evaporation, and alters the microclimate, potentially triggering a chain of environmental responses. This raises concerns about whether such changes could increase abnormal precipitation events, thereby stimulating more widespread slope failures and vegetation changes, ultimately disturbing the landscape. The Baihetan Hydropower Station, located on the lower Jinsha River in China, serves as a case study for exploring these effects. By monitoring long-term surface deformations, abnormal precipitation, topography, geomorphological parameters, and vegetation changes, we have gained insights into the macro disturbances caused by water level fluctuations. Since the reservoir began storing water, slope failures have markedly increased, particularly in the form of creeping slopes and bank collapses in the drawdown zone. This period has also seen a reduction in total precipitation, an increase in abnormal precipitation, and slower vegetation growth. Further analysis reveals that while rising water levels primarily destabilize reservoir shore slope-failures, precipitation also significantly influences this instability. The greatest threat to shore stability arises when water levels drop and are followed by heavy rainfall. Although the severity of abnormal precipitation has increased post-impoundment, it has not led to more extreme precipitation events. Vegetation growth on active slopes near the reservoir is mainly controlled by changes in precipitation, with vegetation decline due to slope instability being limited and not widespread. These findings contradict initial assumptions, indicating that landscape disturbances due to water storage are limited and have not led to severe, uncontrollable chain reactions.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"257 ","pages":"Article 109197"},"PeriodicalIF":5.4,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144146844","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unveiling water table tipping points in peatland ecosystems: Implications for ecological restoration","authors":"Mar Albert-Saiz ,&nbsp;Mariusz Lamentowicz ,&nbsp;Anshu Rastogi ,&nbsp;Radosław Juszczak","doi":"10.1016/j.catena.2025.109149","DOIUrl":"10.1016/j.catena.2025.109149","url":null,"abstract":"<div><div>Peatlands play a significant role in the global carbon cycle as an essential organic carbon sink. However, a concerning trend reveals that more than 15 % of peatlands worldwide have been drained; this hydrological problem is expected to deepen with the ongoing global warming. The appropriate management of the water table depth (WTD) emerges as an essential strategy in the protection of peatlands from drainage and degradation. These ecosystems are also under the influence of seasonal hydrological changes, which exert profound effects. A low water table facilitates oxygen availability in the peat, leading to the decomposition of organic matter and significant shifts in vegetation. Conversely, high water table levels encourage anaerobic conditions, fostering peat accumulation while suppressing microbial activity. Extreme climate events or human interventions further trigger water table fluctuations, potentially pushing peatlands beyond recovery thresholds and leading to irreversible degradation. Therefore, this comprehensive review and <em>meta</em>-analysis explores the responses of peatlands to water table fluctuations. We tried to identify critical tipping points driving vegetation succession, nutrient cycling, acidity levels, and exoenzymatic activities. The study found out deeper levels of WTD are needed to trigger the chain of effects in peatland balance for bogs (from –31 cm to –23 cm) than for fens (from –14 cm to –12 cm)( and that some changes are only directly related with WTD in undisturbed peatlands (e.g. changes in acidity, less stable vegetation succession). Recognising these critical thresholds is of utmost importance, as it holds the key to preventing further degradation of invaluable peatland ecosystems and appropriate restoration methods.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"257 ","pages":"Article 109149"},"PeriodicalIF":5.4,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144146843","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Aridity regulates the vital drivers of soil organic carbon content in the Northeast China","authors":"Huiying Wen ,&nbsp;Zheng Sun ,&nbsp;Fei Yang ,&nbsp;Ganlin Zhang","doi":"10.1016/j.catena.2025.109192","DOIUrl":"10.1016/j.catena.2025.109192","url":null,"abstract":"<div><div>The increasing prevalence of aridity events profoundly influences the terrestrial soil organic carbon (SOC) dynamics. Varying aridity conditions may induce differential effects of changing environments on SOC content. Current knowledge regarding how aridity intervenes with the key drivers of SOC remains limited, especially in complex ecosystems along aridity gradients. Here, we utilized nearly 1,000 soil samples (0–20 cm and 20–100 cm) from the Second National Soil Survey in 1980 s as the foundation. Employing machine learning methods, generalized additive model (GAM), and structural equation model (SEM), we estimated the spatial patterns of SOC in the Northeastern and elucidated the intervention of aridity on the key drivers of SOC. Our findings revealed that SOC content gradually decreased along the aridity gradient from the northeast to the southwest in both soil layers. Aridity and exchangeable Ca²⁺ were identified as the key factors controlling this pattern. Results from nonlinear analysis demonstrated a non-stationary response of SOC content to aridity. As the intensity of aridity increased, SOC content shifted from a slow decline to a rapid decrease, with numerical thresholds identified in the value space (0–20 cm, 0.48; 20–100 cm, 0.45). The range of aridity thresholds in the numerical space delineated the type boundaries of phaeozems and luvisols in geographical space. Results from SEM indicated that aridity and its critical thresholds significantly coordinated the key driving forces of SOC content. In the aridity environment beyond the threshold, with the contraction of other drivers, the controlling role of exchangeable Ca²⁺ was further amplified and consistently mediated SOC content. We emphasized the contribution of aridity to understanding of SOC driving patterns, with other drivers exhibiting different behaviors in their contributions to SOC, accompanied by differences (even thresholds). This provides an important prerequisite for further understanding the response of soil carbon pool to ecosystem environmental changes.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"257 ","pages":"Article 109192"},"PeriodicalIF":5.4,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144139307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Patterns and drivers of soil organic carbon fractions and persistence in coastal wetlands of China","authors":"Lele Wu ,&nbsp;Zhaoliang Song ,&nbsp;Xinyu Zhang ,&nbsp;Yuan Guo ,&nbsp;Yidong Wang ,&nbsp;Changxun Yu ,&nbsp;Yunying Fang ,&nbsp;Iain P. Hartley ,&nbsp;Ji Chen ,&nbsp;Shaopan Xia ,&nbsp;Xiaoguang Ouyang ,&nbsp;Wenhai Mi ,&nbsp;Ding He ,&nbsp;Cong-Qiang Liu ,&nbsp;Hailong Wang","doi":"10.1016/j.catena.2025.109186","DOIUrl":"10.1016/j.catena.2025.109186","url":null,"abstract":"<div><div>Coastal wetlands have disproportionately high carbon (C) sequestration rates and long-term sustainable C sequestration capacity, contributing to the mitigation of global climate change. Previous studies have mainly focused on the assessment of bulk soil organic C (SOC) in coastal wetlands, neglecting the form in which C is stored, its stability and driving factors, which hinders our in-depth understanding of C sequestration capacity and underlying mechanisms. In this study, we sampled 157 plots across coastal wetlands in China, covering tropical, subtropical, and temperate climates to gain a detailed understanding of the distribution, stability, and control mechanisms of SOC fractions. Our results showed that the SOC in the topsoil (0–10 cm) was co-dominated by mineral-associated organic C (MAOC) and particulate organic C (POC) in mudflats, temperate and subtropical salt marshes, and subtropical mangroves, but not in tropical mangroves. The content of dissolved organic C (DOC, 0.12 ± 0.08 g kg⁻¹) was only 1.15 ± 0.06 % of bulk SOC. The POC became more dominant relative to MAOC and DOC as SOC content increased. We found that soil properties (total nitrogen, bulk density, and particle size, etc), were the primary explanatory variables for SOC fractions content and persistence, accounting for 58 %, 64 %, 38 %, 53 %, and 34 % of total variation in MAOC, POC, DOC, MAOC/SOC, and C/N, respectively. Although climate and vegetation factors did not directly control C contents in soil matrix and persistence, they interacted strongly with edaphic variables explaining 8 %, 16 %, 11 %, 12 %, and 13 % of the total variation in the above variables, respectively. Our results suggest that the increase in SOC, especially POC, reduced its persistence, so the implementation of C management strategies in coastal wetlands should integrate SOC sequestration and stability to maximize benefits.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"257 ","pages":"Article 109186"},"PeriodicalIF":5.4,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144139306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Annual variation in sediment connectivity in karst watersheds of southwest China","authors":"Si Cheng ,&nbsp;Xingxiu Yu ,&nbsp;Zhenwei Li ,&nbsp;Liangxia Duan ,&nbsp;Xianli Xu ,&nbsp;Kelin Wang","doi":"10.1016/j.catena.2025.109173","DOIUrl":"10.1016/j.catena.2025.109173","url":null,"abstract":"<div><div>Sediment connectivity reflects the connectivity between sediment sources and sinks and contributes to understanding soil erosion and sediment transport processes. However, the potential effects of climatic factors and vegetation restoration on sediment connectivity have not been fully recognized, especially in the karst area of southwest China, which has a serious rocky desertification and fragile ecological environment. This study aims to quantify the connectivity index (IC), runoff, and sediment yield changes induced by the coupling impacts of climate change and vegetation restoration in six typical karst watersheds. Annual climate, vegetation, land use, soil, runoff, and sediment yield data were collected during 2000 ∼ 2019. The parameters of IC were calculated based on the source-sink landscape index. The Partial least squares structural equation model (PLS-SEM) was used to quantify the impacts of climate change and vegetation restoration on changes in IC, runoff, and sediment yield. The results show that the average IC value ranged from 2.10 to 2.97 during 2000 ∼ 2019, with an insignificant decreasing trend. PLS-SEM analysis shows that climatic and vegetation factors explained 1 ∼ 7 % of the changes in IC values and 53 %∼90 % of the runoff dynamics. Climate factors, vegetation dynamics, runoff, and IC values together explained 21 %∼67 % of the variations in sediment yield. These results can facilitate understanding the temporal variation in IC and are significant for ecological restoration and sediment delivery control in karst areas.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"257 ","pages":"Article 109173"},"PeriodicalIF":5.4,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144139467","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influencing mechanism of microtopography on erosion hydrodynamics on bare slopes of pika mounds in alpine meadows in the Yellow River source area, Western China","authors":"Shengchun Tong ,&nbsp;Guorong Li ,&nbsp;Xilai Li ,&nbsp;Jinfang Li ,&nbsp;Yong Li ,&nbsp;Dalin Yue ,&nbsp;Jianyun Zhao ,&nbsp;Haili Zhu ,&nbsp;Yabin Liu ,&nbsp;Wenting Chen ,&nbsp;Xiasong Hu","doi":"10.1016/j.catena.2025.109158","DOIUrl":"10.1016/j.catena.2025.109158","url":null,"abstract":"<div><div>The mound-building behavior of plateau pika is one of the important factors leading to meadow degradation and soil erosion in the Yellow River source area of Western China, but little is known about the influencing mechanism of microtopography on erosion hydrodynamic characteristics of bare slopes of pika mounds. In this study, we analyzed microtopography and erosion hydrodynamic characteristics on bare slopes of pika mounds under subrainfall conditions through simulation of rainfall events at six intensities (all lasting 60 min), and revealed the influencing mechanism of slope microtopographic changes on erosion hydrodynamics by using redundancy analysis (RDA) and structural equation modeling (SEM). The results showed that the maximum average erosion depth was 4.159 cm, and the maximum erosion areas accounted for 93.40 % of the total area of runoff plots; intense erosion took place mainly in the upper half of the pika mounds, while deposition was mainly limited to the lower half of the pika mounds. Surface flow velocity, flow regime parameters, and erosion power parameters all showed an increasing trend with rainfall intensity (P &lt; 0.05), while the resistance parameters showed a decreasing trend with rainfall intensity (P &lt; 0.05); all slope flows were laminar (<em>Re</em> &lt; 500), but transitioned from slow flows to rapid flows at a higher rainfall intensity. The RDA results showed that surface cutting degree was the key factor influencing surface runoff volume and sediment yield and hydrodynamic parameters, and that the Reynolds number could be the best hydrodynamic parameter to characterize runoff volume and sediment yield. SEM analysis showed that microtopography influenced water erosion either directly (with a path coefficient of 0.856) or indirectly through hydrodynamic characteristics (path coefficient = 0.742). This research showed that microtopography of the bare slopes had a significant effect on water erosion, and was linked to hydrodynamic characteristics to build up a highly complex dynamic exchange process.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"257 ","pages":"Article 109158"},"PeriodicalIF":5.4,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144134316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A coupled model of surface water-groundwater interaction with the effect of riverbed deformation in the alluvial channel","authors":"Linlin Li ,&nbsp;Hang Li ,&nbsp;Genguang Zhang ,&nbsp;Defu Liu ,&nbsp;Yao Xiao ,&nbsp;Ying Liu ,&nbsp;Jiahao Zou","doi":"10.1016/j.catena.2025.109193","DOIUrl":"10.1016/j.catena.2025.109193","url":null,"abstract":"<div><div>Hyporheic exchange process is a common mode of surface water-groundwater interaction, involving the transport of substances, nutrients and energy, which is an important foundation for river ecology. However, the effect of riverbed deformation driven by weir in natural rivers remains unclear. In this study, the effect of local scour pit created by low-head weirs on hyporheic exchange process was studied by the coupled model of surface water-groundwater. While many studies assume static riverbed conditions, this study integrates a dynamic surface water model that accounts for sediment transport and evolving scour pits, while employing a steady-state representation for subsurface flow to reflect the gradual adjustment of hyporheic exchange. The variation of the local scour depth, hyporheic exchange flux, hyporheic zone pressure field and temperature response area were investigated under different weir height and flow discharge. The results showed that: (a) the increasing weir height significantly enhanced hydrodynamic effect, with the morphological changes in scour pits altering the distribution of hyporheic zone pressure field and further intensifying surface water-groundwater exchange; (b) when the weir height increased from 15 cm to 25 cm, the scour pit depth increased from 9 cm to 25 cm, the volume of the local scour pit increased by approximately 3.3 times, and the hyporheic exchange flux increased to a maximum value of 0.011 m²/s; (c) the peak downwelling Darcy velocity in the hyporheic zone increased from 0.0039 m/s to 0.0067 m/s as the flow discharge increased from 0.0621 m³/s to 0.1200 m³/s; (d) the scour pit formation altered the local bed topography, then influencing the hyporheic exchange pathways and rates; the peak downwelling Darcy velocity with the riverbed scouring effect was 2.5 times higher than that of the others, with the hyporheic exchange flux increasing by 1.5 times. This study can provide theoretical insights for optimizing low-head weir designs and water management in river ecological restoration.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"257 ","pages":"Article 109193"},"PeriodicalIF":5.4,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144134315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}