Journal of Hydrology最新文献

{"title":"Study of the transverse distribution of suspended sediment concentration in compound channel with emergent vegetation on floodplain","authors":"Da Li ,&nbsp;Zhonghua Yang ,&nbsp;Song Zhang ,&nbsp;Man Guo","doi":"10.1016/j.jhydrol.2025.133444","DOIUrl":"10.1016/j.jhydrol.2025.133444","url":null,"abstract":"<div><div>Vegetation which widely exists in natural river ecosystem plays a significant role in water purification, river evolution and soil conservation. Understanding how the vegetation on floodplain influences the transport and distribution of suspended sediment is the prerequisite for studying the erosion and deposition of riverbed and the changes of water quality. Therefore, this paper adopted flume experiments and theoretical analysis to investigate the influence of floodplain with emergent vegetation on the transport of suspended sediment in compound channel. It was found that the depth-averaged suspended sediment concentration (SSC) decreases from the main channel to the floodplain as a whole. And the averaged SSC of the whole cross section decreases from 0.34 kg/m³ to 0.04 kg/m³ with the vegetation density increasing from 0 to 1.56 m⁻¹ in the experiments, which leads to more deposited sediment. At the same time, it was observed that the deposited sediment was transferred from the main channel to the vegetated floodplain. Then, this study established the transverse distribution model of the depth-averaged SSC under the influence of emergent vegetation on floodplain with the bottom turbulence and large coherent structure being considered. The validation results indicated the model has good accuracy and correlation. It provides the theoretical foundation for quantifying the sediment transport capacity in the compound channel with vegetated floodplain, which is helpful for the restoration and protection of ecological river.</div></div>","PeriodicalId":362,"journal":{"name":"Journal of Hydrology","volume":"660 ","pages":"Article 133444"},"PeriodicalIF":5.9,"publicationDate":"2025-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143923950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Variation of salinity with water level in shallow lakes is complex and rich in information","authors":"Gavan S. McGrath ,&nbsp;Barton Huntley ,&nbsp;Michael P. Venarsky","doi":"10.1016/j.jhydrol.2025.133347","DOIUrl":"10.1016/j.jhydrol.2025.133347","url":null,"abstract":"<div><div>Global trends of lake salinization and desiccation from climate change, land use change and water abstraction are impairing ecosystem services and freshwater biodiversity. In semi-arid lakes salinity tends to vary inversely with water levels: fresh when fuller and more saline at lower water levels. This long-recognized covariation is sometimes used to inform salt budgets from lake bathymetry and paleoclimate from salinity proxies, but limnologists have no understanding why they differ from lake to lake or a theoretical underpinning for how salinity scales with water level. Here, for the first time, theory for this scaling is developed alongside a systematic analysis of data from 152 shallow lakes showing, contrary to common assumptions, salinity varies with water level as a piecewise power-law with up to four segments. The segments evident in data sequentially describe dominance by salt precipitation, vertical water fluxes, lateral outflows, and equilibration with inflows as water levels increase. The exponents are shown theoretically and empirically to depend upon power-law scaling of bathymetry and lake outflow. Understanding these physical controls provides a means to better predict changes to salinity in semi-arid lakes facing projections of warming, drying, and ongoing land use change, as well as the effects of some adaptive management responses.</div></div>","PeriodicalId":362,"journal":{"name":"Journal of Hydrology","volume":"660 ","pages":"Article 133347"},"PeriodicalIF":5.9,"publicationDate":"2025-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143931827","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of hydrogeological and numerical parameters on the simulation of an upper saline plume and fresh submarine groundwater discharge","authors":"Marieke Paepen ,&nbsp;Maarten Minnaert ,&nbsp;Janek Greskowiak ,&nbsp;Thomas Hermans","doi":"10.1016/j.jhydrol.2025.133439","DOIUrl":"10.1016/j.jhydrol.2025.133439","url":null,"abstract":"<div><div>At the land-sea transition, the distribution of salt and fresh groundwater is the result of a complex balance between land- and sea-related processes and the subsurface properties. Fresh rainwater, recharging on land, passes through the so-called subterranean estuary (STE) which constitutes an important entry gate for nutrients and/or pollutants to the sea. In some conditions, tidal-induced seawater recirculation forms an upper saline plume (USP), which overlies the discharging freshwater. From below, the freshwater discharge tube is confined by the classic density-driven saltwater wedge. The size, geometry and location of the USP and wedge, as well as the water fluxes and residence times, are dependent on the tidal cycle, the recharge on land, and the aquifer and beach properties. Groundwater modelling has been found useful to analyse the sensitivity of aquifer properties and forcing factors on the salinity distribution within the STE. However, the dynamics of the shore makes it difficult to accurately represent the seaside boundary condition of STE groundwater models. This contribution shows that the boundary condition type and the accompanying heads should be well-chosen and that phase-averaged boundary conditions applied in steady-state can provide a realistic salinity distribution, similar to transient simulations. Next to this, the sensitivity of the recharge rate, hydraulic conductivity, and the heterogeneity by means of a LPL in the intertidal zone on the fresh submarine groundwater discharge (FSGD) is systematically assessed. The findings are applied to successfully simulate the FSGD patterns observed along the high energy beach of the western Belgian coast.</div></div>","PeriodicalId":362,"journal":{"name":"Journal of Hydrology","volume":"660 ","pages":"Article 133439"},"PeriodicalIF":5.9,"publicationDate":"2025-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143912444","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nitrogen response and transformation processes in karst water system using bacterial indicators","authors":"Wenhui Zhao,&nbsp;Mingming Luo,&nbsp;Jing Chen,&nbsp;Zhihao Zhou,&nbsp;Xiangyu Peng,&nbsp;Zehao Zhao,&nbsp;Yongguang Jiang","doi":"10.1016/j.jhydrol.2025.133442","DOIUrl":"10.1016/j.jhydrol.2025.133442","url":null,"abstract":"<div><div>Concentrated recharge processes significantly influence the biogeochemical behavior of nitrogen in karst water systems. To further understand the nitrogen response and transformation processes under these conditions, this study employs hydrological monitoring, hydrogeochemistry, and bacterial indicators to investigate the water environment changes between the inlet and outlet of Qinglongkou spring, South China. The results show that nitrifying bacteria drive nitrification, dominating biogeochemical processes of nitrogen. Heavy rainfall events alter the bacterial community structure associated with nitrogen cycling. The abundance of nitrification contributors (<em>Ellin6067</em>, <em>MND1</em>, and <em>Nitrospira</em>) exhibit a positive correlation with the flow rate of the QLK spring. The changes in nitrification functional genes abundance are associated with alterations in the dominant bacterial community structure. Nitrogen (NH₄⁺-N and NO₃^–-N) and functional genes (AOB-<em>amoA</em>, <em>nirK</em>, <em>narG</em>) accumulate to relatively high levels after rainfall event at both sinkholes and spring outlet, with AOB-<em>amoA</em> abundance positively correlated with flow rate, peaking at 7.46 × 10⁵ copies/mL. The AOB-<em>amoA</em> flux in Qinglongkou spring is similar to that in the sinkholes, reflecting the resilience and biogeochemical behavior of nitrifying bacteria under heavy precipitation conditions, but 16S rDNA, <em>nirK</em>, and <em>narG</em> fluxes decrease by 52.7 % to 68.3 %. This research sheds light on the impact of concentrated recharge on nitrogen response and transformation in typical karst areas, providing valuable bacterial information for mitigating nitrate pollution during rainstorm.</div></div>","PeriodicalId":362,"journal":{"name":"Journal of Hydrology","volume":"660 ","pages":"Article 133442"},"PeriodicalIF":5.9,"publicationDate":"2025-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143912476","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-objective optimization of reservoir group operation after Inter‑basin water transfer jointing SWAT model and NSGA-II","authors":"Ruimin Liu ,&nbsp;Yue Liu ,&nbsp;Lijun Jiao ,&nbsp;Linfang Wang","doi":"10.1016/j.jhydrol.2025.133431","DOIUrl":"10.1016/j.jhydrol.2025.133431","url":null,"abstract":"<div><div>Inter-basin water transfer (IBWT) projects were widely proposed to solve regional water resource shortages. However, the impact of reservoir group management measures after IBWT on the economy and ecology is often overlooked. In this study, the cyclic coupling of the soil and water assessment tool (SWAT) and the second generation of the Non-dominated Sorting Genetic Algorithm (NSGA-II) was realized. Performance analysis of NSGA-II showed that the best-fit parameters of population size, generations, mutation, and crossover were 100, 50, 0.1, and 0.8, respectively. Based on the coupling model, the optimization of three objectives about economy, resources, and environment and the relationship between discharge flow and objectives were analyzed in the Fenhe River Basin. Optimization results showed IBWT project made power generation increase by 88.8%, water shortage decrease by 19%, and water quality improve by 15.43%. There was a non-linear competitive relationship between F2, representing the benefits of water supply, and F1, representing the benefits of hydropower generation, as well as between F2 and F3, representing the benefits of water quality. In this non-linear competitive relationship, the benefits of F1 and F3 brought by unit F2 were reduced to 1/57 and 1/75 of the original respectively. The points that marginal cost of F2 equals marginal benefits of F1 and F3 were served as reference points to balance the benefit among objectives and calculate the optimal total benefit point (1378, 36.49, 36.63) of the three objectives. The driving effects of different objectives on the discharge flow curve were different through the analysis of reservoirs discharge typical plans. The reservoir discharge plan for the best benefit of F3 (F3B) had maximum annual average discharge flow and proportion of discharge flow during flood season to dilute pollutants in the river channel. Meanwhile, the plan for the best benefit of F2 (F2B) had minimum discharge flow to reduce the water resources overflow. Besides, there is a complementary situation in time of different reservoirs discharge flow. These results could provide effective guidance for water resources management after implementing IBWT projects.</div></div>","PeriodicalId":362,"journal":{"name":"Journal of Hydrology","volume":"660 ","pages":"Article 133431"},"PeriodicalIF":5.9,"publicationDate":"2025-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143903810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Feasibility of reducing the capacity of plain reservoirs through the joint optimal scheduling of mountain and plain reservoirs","authors":"Dingrong Zhai,&nbsp;Aijun Guo,&nbsp;Yimin Wang,&nbsp;Jianxia Chang,&nbsp;Yibin Liang,&nbsp;Zhehao Li,&nbsp;Jingyao Sun,&nbsp;Zhentao Tang,&nbsp;Rui Zheng","doi":"10.1016/j.jhydrol.2025.133410","DOIUrl":"10.1016/j.jhydrol.2025.133410","url":null,"abstract":"<div><div>Plain reservoirs are critical to water allocation in arid regions due to their low cost and proximity to irrigation areas. However, its remarkable evaporation and seepage losses exacerbate the water resources shortage in arid regions. Therefore, mountain reservoirs present a superior alternative to plain reservoirs owing to their low water loss. This study proposes a joint operational model of mountain and plain reservoirs in arid inland river basin to quantify the potential capacity reduction of plain reservoirs. The Aksu River Basin in China is selected as a case study to evaluate the feasibility of replacing plain reservoir capacity with mountain reservoirs. The results show that mountain reservoirs increased the guaranteed irrigation water supply rate by 18.3 % in the planning year, while reducing the utilization of plain reservoirs. Additionally, the mountain reservoirs tend to store water with priority during high-flow periods, thereby reducing the water storage volume in plain reservoirs. By contrast, plain reservoirs supply water preferentially during periods of deficit. Worthy of note is that, mountain reservoirs still have considerable available storage. In this context, plain reservoirs can be reduced by 1.74 × 10⁸ m³ (74.04 %) in the planning year, saving 0.32 × 10⁸ m³ of water. By comparison, the plain reservoirs should remain unchanged in the current year. In summary, reducing the storage capacity of plain reservoirs in arid basin is conducive to lowering evaporation and seepage losses. This study provides a high-efficient way of utilizing water resources utilizing in arid regions from the viewpoint of reservoir capacity replacement in mountain-plain reservoir systems.</div></div>","PeriodicalId":362,"journal":{"name":"Journal of Hydrology","volume":"660 ","pages":"Article 133410"},"PeriodicalIF":5.9,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143943459","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impacts of dams on fish habitat connectivity greatly outweigh climate change in the Jinsha river basin, China","authors":"Xiongfeng Bai ,&nbsp;Peng Zhang ,&nbsp;Zhi Yang ,&nbsp;Ditao Zhang ,&nbsp;Xianghong Dong ,&nbsp;Siyang Wang ,&nbsp;Sun Heying ,&nbsp;Yunye Feng ,&nbsp;Shuang Li ,&nbsp;Lihua Xiong ,&nbsp;Jianbo Chang","doi":"10.1016/j.jhydrol.2025.133411","DOIUrl":"10.1016/j.jhydrol.2025.133411","url":null,"abstract":"<div><div>In the context of the surge in hydropower development, the reduction in river network connectivity and the subsequent loss of biodiversity in riverine ecosystems has become a central topic of discussion. Current river connectivity assessments focus more on the physical structure connectivity of the river networks but rarely consider the survival needs of organisms. This study proposes a fish habitat connectivity method that integrates potential habitat distribution area and dendritic connectivity index (DCI) to establish the fish-specific river connectivity index (FCI). Four endemic fish living in different regions and with different ecological types (warm-water and cold-water fishes) in the Jinsha River Basin (JRB), China, were selected for spatial–temporal assessment of FCI. The effects of future climate change on FCI were also explored. Firstly, the DCIs for three periods (1970–2000, 2001–2020, and a future period) categorized by the number and scale of dam construction in the JRB were calculated. Then, the potential habitat distribution of target fish species under SSP126 and SSP585 scenarios for each period were projected using species distribution models. Finally, the FCIs, which consider climate change, dam construction, and species mobility, were derived by overlapping the DCI and habitat suitability index. The results show that the large-scale dam constructions in the mid-lower reaches of the JRB between 2000 and 2020 led to a significant decline in DCI, with only the headwater regions of the basin maintaining a DCI above 10%. Although suitable habitat would expand under the impact of climate change, habitat connectivity of all four fish species declined sharply over time with the future FCI falling below 10%. Dam construction had a greater impact on habitat connectivity than climate change. This study provides beneficial methods that comprehensively considers the factors of dam construction, climate change, and species mobility to evaluate the habitat connectivity for specific fish species and reveal the profound impacts of the dam construction on fish habitat connectivity to support for the protection of critical species in the context of water resources development and climate change.</div></div>","PeriodicalId":362,"journal":{"name":"Journal of Hydrology","volume":"660 ","pages":"Article 133411"},"PeriodicalIF":5.9,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143899342","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 the effects of heating temperature on the deuterium and oxygen-18 biases of plant stems bulk water due to cryogenic vacuum distillation","authors":"Pei Zhao ,&nbsp;Yan Li","doi":"10.1016/j.jhydrol.2025.133408","DOIUrl":"10.1016/j.jhydrol.2025.133408","url":null,"abstract":"<div><div>Cryogenic vacuum distillation (CVD) has been proven to significantly deplete deuterium in plant stem water. In this study, rehydration and pot experiments were conducted to investigate the effects of different heating temperatures on deuterium and oxygen-18 biases caused by CVD. For rehydration experiments, the mean δ²H offsets (the difference between the isotopic ratio of a sample and the reference value) were −15.4 ± 4.3 ‰, −10.8 ± 1.1 ‰, −6.6 ± 0.9 ‰ and −4.5 ± 1.0 ‰ for 75 °C, 100 °C, 150 °C and 200 °C heating temperature, respectively. High temperatures (150 °C, 200 °C) significantly reduced δ²H bias compared to low temperatures (75 °C, 100 °C). Absolute water content (AWC) had a significantly greater influence on δ²H and δ¹⁸O offsets across temperatures and species than relative water content. In pot experiment, most water extracted at 200 °C heating temperature showed no significant difference between extracted water and source water, for both δ²H and δ¹⁸O (except one species). However, these isotopic offsets exhibited a significantly negative relationship with the AWC of plant stem, indicating that the optimal extraction temperature in CVD experiments would vary depending on the plant’s water content. The improved isotopic bias at higher temperatures, along with extraction efficiency data from CVD experiments, suggests that a very small fraction of plant water, possibly more tightly bound within the plant matrix, is not effectively extracted at 75 °C and 100 °C. This very small fraction of retained water is likely a primary contributor to the observed bias in δ²H measurements. Based on these findings, it is recommended to sample plants with AWC ranging from 1.0 to 1.5 g for high-temperature extraction (e.g., 200 °C) in CVD experiments to decrease deuterium bias for plant water studies. Future studies should investigate whether higher heating temperatures can reduce the isotopic biases in the laboratories that have observed discrepancies.</div></div>","PeriodicalId":362,"journal":{"name":"Journal of Hydrology","volume":"660 ","pages":"Article 133408"},"PeriodicalIF":5.9,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144069746","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Coastal creeks as greenhouse gas hotspots: the role of nutrient availability and microbial activity","authors":"Guanpeng Chen ,&nbsp;Jianuo Gao ,&nbsp;Ping Yang ,&nbsp;Wenjing Liu ,&nbsp;Dongyao Sun ,&nbsp;Yongxin Lin ,&nbsp;Chuan Tong ,&nbsp;Wenjing Tan ,&nbsp;Pingping Guo ,&nbsp;Hong Yang","doi":"10.1016/j.jhydrol.2025.133412","DOIUrl":"10.1016/j.jhydrol.2025.133412","url":null,"abstract":"<div><div>Coastal creeks are ubiquitous in wetland ecosystems, and they act as conduits for significant inputs of nutrients and anthropogenic carbon from surrounding areas, making them potential hotspots for greenhouse gas (GHG) emission. To date, the spatiotemporal variations in GHG emission across different types of coastal creeks and their environmental drivers remain poorly understood due to the lack of observational data. A field investigation was carried out to analyze the concentrations and fluxes of CO₂ and CH₄ across three coastal creeks (designated as CC1, CC2 and CC3) within the Shanyutan Wetland in southeastern China. These creeks received exogenous input from different sources. The results indicated that CO₂ and CH₄ concentrations in all three creeks remained persistently oversaturated, with concentrations in the range of 14.5–61.5 µmol L⁻¹ and 1.1–11.8 µmol L⁻¹, respectively. The estimated emission fluxes varied in the range of 0.4–3.6 mmol CO₂ m⁻² h⁻¹ and 40.2–581.1 µmol CH₄ m⁻² h⁻¹. The mean CO₂ efflux over the four seasons was highest in CC1 (1.9 mmol m⁻² h⁻¹) and lowest in CC2 (0.8 mmol m⁻² h⁻¹). For CH₄ efflux, the highest value was in CC2, followed by CC3 and CC1. PO₄³⁻ availability was the primary factor affecting the change of CO₂ concentration and emission, while CH₄ were primarily regulated by DOC, DO, TDN and abundances of <em>mcrA</em> and <em>pmoA</em> genes. These results highlighted that coastal creeks are significant atmospheric GHG sources and exogenous inputs substantially influenced their variabilities.</div></div>","PeriodicalId":362,"journal":{"name":"Journal of Hydrology","volume":"660 ","pages":"Article 133412"},"PeriodicalIF":5.9,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143923985","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 migration activities on flood exposure and evaluating sustainable development areas based on hydrodynamic simulations and gridded migration data","authors":"Kai Fei ,&nbsp;Haoxuan Du ,&nbsp;Chi-Cheng Lei ,&nbsp;Liang Gao","doi":"10.1016/j.jhydrol.2025.133425","DOIUrl":"10.1016/j.jhydrol.2025.133425","url":null,"abstract":"<div><div>Migrations to low-lying urban cities in the bay areas tend to increase flood exposure. To tackle the challenges, quantifying migration’s impact on flood exposure and identifying sustainable areas is essential. Here we integrate the flood modelling based on a hydrological-hydrodynamic coupling model and statistical analysis with empirical data to address this research gap through a case study in Guangdong-Hong Kong-Macao Greater Bay Area (GBA). The assessment combines the land use impact on flood extent and the urban development policies. Two satellite precipitation datasets are utilized to predict flood extents independently, with their intersection and union defining the minimum and maximum extents. Empirical grid data are also calibrated with measurements to ensure the accuracy. This assessment reveals that the migration activities increase the flood exposed population by 7.27–14.36 million, accounting for 75–84 % of the increased flood exposure from 2000 to 2020. 35.3 % of migrants move to built-up areas within 1 km of rivers, while 53.5 % settle in areas with slopes less than 1°. These settlement patterns are the main contributors to increased flood exposure, with maximum exposure rates exceeding 60 % in both types of areas. The exposure ratio of built-up areas increased by 5.8–7.4 % over the 20 years. 37–50 % of GBA are assessed suitable for future development by 2020 from the perspective of flood control, with most of these areas in the northern part. The available spaces for some units in the middle GBA are less than 20 %. This study will provide valuable insights for migration and urban development to meet evolving flood exposure.</div></div>","PeriodicalId":362,"journal":{"name":"Journal of Hydrology","volume":"660 ","pages":"Article 133425"},"PeriodicalIF":5.9,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143903811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}