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Pan F, Li Z, Xie H, Xu X, Duan L. Disentangling influences of driving forces on intra-annual variability in sediment discharge in karst watersheds. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 923:171486. [PMID: 38447723 DOI: 10.1016/j.scitotenv.2024.171486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 02/27/2024] [Accepted: 03/03/2024] [Indexed: 03/08/2024]
Abstract
The intra-annual variability in sediment discharge was considerably influenced by the climate variability and vegetation dynamics. Because of the coupled or relationships between climatic and vegetation variables, it is still challenging to decouple the direct and indirect effects of climate variability and vegetation dynamics on hydrological and sediment transport processes. The purpose of this study is to decouple influences of individual driving force on intra-annual distribution of sediment discharge during 2003-2017 using the partial least squares structural equation model (PLS-SEM) method in four typical karst watersheds of Southwest China. The coefficient of variation (Cv), Completely regulation coefficient (Cr), Lorenz asymmetry coefficient and Gini coefficient were used to represent the intra-annual sediment discharge variability. Results showed that the monthly sediment discharge (190 % < Cv < 353 %) exhibited greater variability than its potential affecting factors (18 % < Cv < 101 %). From the PLS-SEM analysis, the water discharge, climate, and vegetation together explain 57 %-75 %, 64 %-79 %, and 53 %-80 % of the total variance in Cv, Cr, and Gini coefficient, respectively. Specifically, water discharge exerts the largest influence on sediment discharge variability (0.65 ≤ direct effect ≤0.97, P < 0.05), while vegetation dynamic mainly indirectly affects sediment discharge variability (-0.88 ≤ indirect effect ≤ -0.01) through influencing water discharge. The climate factors also principally indirectly affect the sediment discharge variability (-0.47 ≤ indirect effect ≤0.19) by affecting water discharge and vegetation. The PLS-SEM can effectively reveal the driving force and influencing mechanism of intra-annual sediment discharge changes, and provide an important reference for regional soil and water resources management in karst watersheds. Future studies can decouple the influences of the extreme climate, unique lithology, discontinuous soil, heterogeneous landscape, and special geomorphology on spatial variability in sediment discharge across different karst watersheds.
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Affiliation(s)
- Fengjiao Pan
- College of Resources, Hunan Agricultural University, Changsha 410128, China
| | - Zhenwei Li
- Huanjiang Observation and Research Station for Karst Ecosystem, Key Laboratory for Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China.
| | - Hongxia Xie
- College of Resources, Hunan Agricultural University, Changsha 410128, China
| | - Xianli Xu
- Huanjiang Observation and Research Station for Karst Ecosystem, Key Laboratory for Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China.
| | - Liangxia Duan
- College of Resources, Hunan Agricultural University, Changsha 410128, China.
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Yu B, Zang Y, Wu C, Zhao Z. Spatiotemporal dynamics of wetlands and their future multi-scenario simulation in the Yellow River Delta, China. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 353:120193. [PMID: 38301474 DOI: 10.1016/j.jenvman.2024.120193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Revised: 01/05/2024] [Accepted: 01/20/2024] [Indexed: 02/03/2024]
Abstract
Wetlands, known as the "kidney of the earth", are an important component of global ecosystems. However, they have been changed under multiple stresses in recent decades, which is especially true in the Yellow River Delta. This study examined the spatiotemporal change characteristics of wetlands in the Yellow River Delta from 1980 to 2020 and predicted detailed wetland changes from 2020 to 2030 with the patch-generating land use simulation (PLUS) model under four scenarios, namely, the natural development scenario (NDS), the farmland protection scenario (FPS), the wetland protection scenario (WPS) and the harmonious development scenario (HDS). The results showed that wetlands increased 709.29 km2 from 1980 to 2020 overall, and the wetland types in the Yellow River Delta changed divergently. Over the past four decades, the tidal flats have decreased, whereas the reservoirs and ponds have increased. The gravity center movement of wetlands differed among the wetland types, with artificial wetlands moving to the northwest and natural wetlands moving to the south. The movement distance of the gravity center demonstrated apparent phase characteristics, and an abrupt change occurred from 2005 to 2010. The PLUS model was satisfactory, with an overall accuracy (OA) value greater than 83.48 % and an figure of merit (FOM) value greater than 0.1164. From 2020 to 2030, paddy fields and tidal flats decreased, whereas natural water, marshes and reservoirs and ponds increased under the four scenarios. The WPS was a relatively ideal scenario for wetlands, and the HDS was an alternative scenario for wetland restoration and food production. In the future, more attention should be paid to restoring natural wetlands to prevent further degradation in the Yellow River Delta. This study provides insights into new understandings of historical and future changes in wetlands and may have implications for wetland ecosystem protection and sustainable development.
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Affiliation(s)
- Bowei Yu
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
| | - Yongge Zang
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China
| | - Chunsheng Wu
- Key Laboratory of Ecosystem Network Observation and Modelling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China
| | - Zhonghe Zhao
- Agricultural Information Institute of Chinese Academy of Agricultural Sciences, Beijing, 100081, China
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Yang T, Yang X, Jia C. Detecting the main driving force of runoff change in the Beiluo River Basin, China. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:89823-89837. [PMID: 37458889 DOI: 10.1007/s11356-023-28537-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 06/28/2023] [Indexed: 08/11/2023]
Abstract
Understanding the evolution of runoff and identifying the main driving force of hydrological cycle changes are essential for water resource management. In this study, the spatial and temporal patterns of climate variables and hydrological factors were explored by applying geostatistical analysis and trend analysis in the Beiluo River Basin (BRB), China, and conversions of land use/cover change (LUCC) were assessed using chord diagrams. Contributions of climate change and human activities to runoff change were quantified employing multiple methods. The results show that annual precipitation and actual evapotranspiration increased significantly during the impact period (2004-2014) (p < 0.05), at rates of 19.3 mm/a and 11 mm/a, respectively, and there was a minor upward trend in annual runoff, at a rate of 0.38 mm/a, while annual potential evapotranspiration decreased slightly at a rate of - 3.3 mm/a. Climate variables were the primary contributor to runoff decrease from 2004 to 2011, with an average contribution of - 79% according to the three methods. Human activities were estimated to account for - 81% of runoff change from 2012 to 2014, which was inextricably linked to the increasing LUCC. The results of this study can provide a theoretical basis for regional water resource management under the influence of climate change and human activities.
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Affiliation(s)
- Tian Yang
- Institute of Marine Science and Technology, Shandong University, Qingdao, China
- Institute of Marine Geology and Engineering, Shandong University, Qingdao, China
| | - Xiao Yang
- Institute of Marine Science and Technology, Shandong University, Qingdao, China
- Institute of Marine Geology and Engineering, Shandong University, Qingdao, China
| | - Chao Jia
- Institute of Marine Science and Technology, Shandong University, Qingdao, China.
- Institute of Marine Geology and Engineering, Shandong University, Qingdao, China.
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Yin S, Gao G, Huang A, Li D, Ran L, Nawaz M, Xu YJ, Fu B. Streamflow and sediment load changes from China's large rivers: Quantitative contributions of climate and human activity factors. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 876:162758. [PMID: 36921863 DOI: 10.1016/j.scitotenv.2023.162758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Revised: 03/05/2023] [Accepted: 03/05/2023] [Indexed: 06/18/2023]
Abstract
Riverine water and sediment discharge drive global material circulation and energy transfer, and they are crucial to the biogeochemical cycle. We investigated the changes in water-sediment fluxes in six major rivers from north to south in China from the mid-1950s to 2020 under the influence of climate change and human activities, and quantified the contributions of these specific influencing factors to water-sediment flux changes. Results showed that streamflow of the Songhua, Liao and Yellow rivers decreased significantly (p < 0.05). The sediment load of all rivers reduced significantly (p < 0.01) except the Songhua River. Streamflow or sediment fluxes to the oceans have increased or stabilized since around 2000, and the terrestrial sediment yielding center in China has shifted southward from the Yellow River to the Yangtze and Pearl rivers. The contribution of precipitation to the streamflow and sediment load changes decreased from north to south across the six rivers. From the mid-1950s to 2020, the underlying land surface change was the dominant contributor (>70 %) to reducing streamflow in the Songhua and Yellow rivers, while climate change (>50 %) was responsible for decreased streamflow in the Liao and Huai rivers. The sediment load reduction of the six rivers was attributed mainly to human activities. Among them, dam construction, human water consumption and catchment land surface change have reduced the total sediment load into the sea by 49 %, 25 % and 19 %, respectively. These results highlight that north-south variability in water and sediment flux are driven by both natural and anthropogenic forcing agents.
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Affiliation(s)
- Shihua Yin
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China; Department of Geography, National University of Singapore, Singapore, Singapore
| | - Guangyao Gao
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Anqi Huang
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Dongfeng Li
- Department of Geography, National University of Singapore, Singapore, Singapore
| | - Lishan Ran
- Department of Geography, The University of Hong Kong, Hong Kong, China
| | - Muhammad Nawaz
- Department of Geography, National University of Singapore, Singapore, Singapore
| | - Y Jun Xu
- Department of Oceanography and Coastal Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Bojie Fu
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
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Wang Y, Yu W, Chang Z, Gao C, Yang Y, Zhang B, Wang Y, Xing B. Effects of dissolved organic matter on the adsorption of norfloxacin on a sandy soil (fraction) from the Yellow River of Northern China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 848:157495. [PMID: 35870586 DOI: 10.1016/j.scitotenv.2022.157495] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 06/20/2022] [Accepted: 07/15/2022] [Indexed: 06/15/2023]
Abstract
Dissolved organic matter (DOM), which exists widely in the environment, coming from different sources, may greatly affect the adsorption of antibiotics. However, the adsorption mechanisms of antibiotics in a sandy soil and the effects of DOM from different sources on the adsorption remain poorly understood. This study systematically investigated the adsorption characteristics of norfloxacin (NOR) onto a sandy soil obtained from the banks of Xi'an in Yellow River and in the presence of three DOM including HDOM (commercially available humic acids), LDOM (derived from fallen leaves) and MDOM (derived from cattle manure). Elemental analysis, UV-vis spectroscopy, 3D-EEM, XPS, TOC, SEM, and FTIR were used to analyze the adsorption mechanism. It was found that all the DOM sources we used could reduce the adsorption of NOR on sandy soil and prolong the reaction time to reach adsorption equilibrium. The decreasing adsorption capacities of NOR by the three types of DOM (10 mg/L) followed the order as: HDOM < LDOM < MDOM, which was related to their aromaticity, polarity and hydrophobicity. These adsorption processes of NOR on sandy soil in the presence of DOM were well fitted by Double-chamber first-order kinetics, Linear model and Freundlich models. Besides, the adsorption reaction was endothermic and spontaneous. Adsorption competition of DOM molecules with NOR, or formation of DOM-NOR complexes in solution resulted in a decrease of sandy soil adsorption capacity. Correspondingly, co-adsorption and cumulative adsorption were also considered to be the key processes that determined NOR adsorption towards sandy soil after adding DOM. Moreover, the adsorption of NOR onto sandy soil exhibited strong pH-dependent characteristic and NOR might be more easily leached from sandy soil in the aquifer at an alkaline pH. High-ion strength suppressed the adsorption. These results would help to understand the fate and risk of NOR under the action of different DOM.
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Affiliation(s)
- Yuting Wang
- School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China
| | - Wenfei Yu
- School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China
| | - Zhaofeng Chang
- Faculty of Environmental Science & Engineering, Kunming University of Science & Technology, Kunming 650500, China; State Environmental Protection Key Laboratory of Environmental Pollution Health Risk Assessment, South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510655, China.
| | - Chanjuan Gao
- College of Resource and Environmental Engineering, Jilin Institute of chemical technology, Jilin 132022, China
| | - Yanni Yang
- School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China
| | - Bei Zhang
- School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China
| | - Yanhua Wang
- School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China.
| | - Baoshan Xing
- Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA 01003, United States
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Miao J, Zhang X, Zhao Y, Wei T, Yang Z, Li P, Zhang Y, Chen Y, Wang Y. Evolution patterns and spatial sources of water and sediment discharge over the last 70 years in the Yellow River, China: A case study in the Ningxia Reach. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 838:155952. [PMID: 35588814 DOI: 10.1016/j.scitotenv.2022.155952] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Revised: 04/27/2022] [Accepted: 05/11/2022] [Indexed: 06/15/2023]
Abstract
The hydrology and sediment processes in large rivers play important roles in maintaining aquatic and coastal ecosystems and advancing civilization and production in human systems. Therefore, quantitatively analyzing the spatiotemporal variability and dynamics of water and sediment discharge in large rivers is essential for improving watershed management and sustainable development in the areas surrounding rivers, especially the Yellow River, which is one of the most sediment-laden rivers in the world. In this study, we analyzed the evolution patterns and spatial sources of water and sediment discharge in the Yellow River from 1951 to 2020 and determined the impacts of different factors on water and sediment discharge variations. The results showed that the annual water and sediment discharge significantly decreased (p < 0.05) over the past 70 years, with an abrupt change occurring in 1986. The first dominant periodicity of water discharge was approximately 29 years, while the first dominant periodicity of sediment discharge was approximately 28 years. In terms of the water and sediment discharge sources, the dominant factor affecting variations in water discharge was water diversion from 1951 to 2020, while the dominant factor affecting variations in sediment discharge was sediment aggradation from 1951 to 1985 and changed to tributary inflow sediment from 1986 to 2020. In addition, the water and sediment discharge changes were also affected by anthropogenic activities, such as water and sediment diversions, dams and reservoirs, and water and soil conservation measures. In particular, the water and sediment interception capabilities of the established soil and water conservation measures gradually became saturated over time. Specifically, the maximum water and sediment interception capabilities of the current soil and water conservation measures were 12.2 billion m3 and 1.9 Gt, respectively. Overall, the results of the present study can help tailor water and sediment regulation countermeasures in the future.
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Affiliation(s)
- Jindian Miao
- School of Soil and Water Conservation, Jixian Research Station for Forest Ecosystem, CFERN/CNERN, Beijing Forestry University, Beijing 100083, China; State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, No. 20, Chegongzhuang West Road, Haidian District, Beijing 100048, China
| | - Xiaoming Zhang
- State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, No. 20, Chegongzhuang West Road, Haidian District, Beijing 100048, China
| | - Yang Zhao
- State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, No. 20, Chegongzhuang West Road, Haidian District, Beijing 100048, China
| | - Tianxing Wei
- School of Soil and Water Conservation, Jixian Research Station for Forest Ecosystem, CFERN/CNERN, Beijing Forestry University, Beijing 100083, China.
| | - Zhi Yang
- Soil and Water Conservation Monitoring Station of Ningxia Hui Autonomous Region, Yinchuan 750002, China
| | - Peng Li
- School of Water Resources and Hydropower, Xi'an University of Technology, Xi'an 710048, China
| | - Yonge Zhang
- State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, No. 20, Chegongzhuang West Road, Haidian District, Beijing 100048, China
| | - Yuxuan Chen
- School of Soil and Water Conservation, Jixian Research Station for Forest Ecosystem, CFERN/CNERN, Beijing Forestry University, Beijing 100083, China
| | - Yousheng Wang
- State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, No. 20, Chegongzhuang West Road, Haidian District, Beijing 100048, China
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Li P, Chen J, Zhao G, Holden J, Liu B, Chan FKS, Hu J, Wu P, Mu X. Determining the drivers and rates of soil erosion on the Loess Plateau since 1901. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 823:153674. [PMID: 35124038 DOI: 10.1016/j.scitotenv.2022.153674] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 01/30/2022] [Accepted: 01/31/2022] [Indexed: 06/14/2023]
Abstract
Attributing soil erosion to land management and climatic drivers is important for global policy development to protect soils. The Chinese Loess Plateau is one of the most eroded areas in the world. However, there has been limited assessment of historic spatial changes in erosion rates on the Loess Plateau and the major contributors driving these spatial changes. In this study, the Revised Universal Soil Loss Equation was empirically validated and employed to assess spatially distributed historical erosion rates on the Loess Plateau from 1901 to 2016. A double mass curve attribution technique was then used to investigate the impact of land management and climatic drivers on the Loess Plateau. Decadal average erosion rates and the total area with intensive erosion (>5000 t km-2 yr-1) experienced a sharp increase from the 1930s to 1970s, followed by a decline to an historic low between the 1980s and 2000s. Mean erosion rates for the 2000s were 54.3% less than those of the 1970s. However, a recent increase in erosion rates was observed between 2010 and 2016. Land management change was the dominant driver of historical erosion rate changes before 2010. Extensive deforestation and farming, driven by population increase, were responsible for intensifying erosion between the 1930s and 1970s, while policy-driven conservation schemes and revegetation led to reduction thereafter. However, the recent increase in erosion between 2010 and 2016 was mainly driven by extreme rainfall events, a major concern given climate change projections. Advanced erosion control strategies are therefore required as part of integrated catchment management that both maintain water supplies for human use during dry periods while reducing erosion during storm events.
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Affiliation(s)
- Pengfei Li
- College of Geomatics, Xi'an University of Science and Technology, Xi'an 710054, China
| | - Jiannan Chen
- College of Geomatics, Xi'an University of Science and Technology, Xi'an 710054, China
| | - Guangju Zhao
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, China; Institute of Soil and Water Conservation, Chinese Academy of Sciences & Ministry of Water Resources, Yangling 712100, China.
| | - Joseph Holden
- water@leeds, School of Geography, University of Leeds, LS2 9JT, UK
| | - Bintao Liu
- Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China
| | - Faith Ka Shun Chan
- School of Geographical Science, University of Nottingham Ningbo China, Ningbo 315100, China
| | - Jinfei Hu
- College of Geomatics, Xi'an University of Science and Technology, Xi'an 710054, China
| | - Peili Wu
- Met Office Hadley Centre, Exeter, UK
| | - Xingmin Mu
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, China; Huanghe research center of Hohai University, Hohai University, Nanjing 210098, China.
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Impact of Climate Change on Water Resources in the Western Route Areas of the South-to-North Water Diversion Project. ATMOSPHERE 2022. [DOI: 10.3390/atmos13050799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The South-to-North Water Diversion Project (SNWDP) is a national strategic project for water shortages in northern China. Climate change will affect the availability of water resources in both source and receiving areas. A grid-based RCCC-WBM model based on climate projections from nine Global Climate Models under SSP2-4.5 was used for analyzing the changes in temperature, precipitation, and streamflow in the near future (2025–2045, NF) and far future (2040–2060, FF) relative to the baseline (1956–2000). The results showed that: (1) the temperature of the western route will increase significantly in the NF and FF with an extent of 1.6 °C and 2.0 °C, respectively, (2) precipitation will very likely increase even though Global Climate Model (GCM) projections are quite dispersed and uncertain, and (3) over half of the GCMs projected that streamflow of receiving area will slightly increase with a rate of 1.68% [−8.67%, 12.3%] and 2.78% [−3.30%, 11.0%] in the NF and FF, respectively. Climate change will support the planning of the western route to a certain extent. However, water supply risk induced by the extreme situation of climate change should be paid adequate consideration when the project operates in practice due to the large dispersion and uncertainty of GCM projections.
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Coupling Effects of Precipitation and Vegetation on Sediment Yield from the Perspective of Spatiotemporal Heterogeneity across the Qingshui River Basin of the Upper Yellow River, China. FORESTS 2022. [DOI: 10.3390/f13030396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Interactions between precipitation, vegetation, and erosion are crucial and not fully solved issues in the area of earth surface processes. The Qingshui River Basin (QRB), as the main sediment source tributary of the upper reaches of the Yellow River, is characterized by spatial heterogeneity of rainfall, vegetation, and soil erosion. In this study, we investigated the spatiotemporal variations of sediment yields within the QRB and further identified the coupling effects of precipitation and vegetation on soil erosion. We collected annual (1955 to 2016) and daily (2006 to 2016) hydrological and sediment series from six hydrological stations, which subdivided the whole basin into six different sub-basins with heterogeneity in climate and landscape. Variations in parameter a of the sediment rating curves among the six sub-basins continuously declined, showing the continuously increasing effect of vegetation coverage on reducing soil erosion. The unique combination of relationships between precipitation characteristics and vegetation patterns in six sub-basins and these coupling effects resulted in different precipitation–vegetation–erosion patterns in six sub-basins. Sediment yield followed bell-shaped relationships with vegetation and precipitation, with a clear critical threshold at normalized difference vegetation index (NDVI) = 0.36/precipitation = 100 mm at a monthly scale. Based on these thresholds, the non-linear relationships between precipitation, vegetation, and erosion were also explained. We also found that reducing the time lags in which vegetation follows precipitation may be effective in suppressing sediment yield. These findings could provide a quantitative approach to estimating the potential changes in sediment yield associated with proposed ecological rehabilitation schemes in this region.
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