Changjiang Water Research Articles

Hypoxia Triggered by Expanding River Plume on the East China Sea Inner Shelf During Flood Years

AbstractThe frequency of riverine floods is predicted to increase in East Asia. However, the response of coastal hypoxia (<63 μmol L−1) to floods has not been well understood. In the summer of 2020, characterized by one of the most significant Changjiang water fluxes in three decades, we conducted a cruise during the flood period on the East China Sea inner shelf. Our observations revealed severe bottom hypoxia with a maximum spatial coverage of ∼11,600 km2 and a minimum dissolved oxygen concentration (DO) of 21 μmol L−1. In the surface layer, the relationships between salinity and nitrate, dissolved inorganic carbon (DIC) indicated significant organic matter production, validated by a high‐Chlorophyll‐a (Chl a) patch (>5 μg L−1). Furthermore, the significant relationship between apparent oxygen utilization and DIC of deep waters reveals that the organic matter decomposition primarily drove the hypoxia during the flood period. Episodic wind events also influenced bottom DO and DIC, by transporting surface waters to the deep. Multiple‐years data set shows that the average Changjiang nitrate flux during flood years is about 1.4 times that during non‐flood years. The flood waters mix with estuarine waters, forming the high‐nutrient plume waters, which expanded farther offshore during the flood period. While high turbidity remained confined to the inner estuary. Consequently, the high‐Chl a area significantly expanded, which significantly exacerbated the hypoxia.

Three datasets from the Changjiang Water Resources Commission of the Ministry of Water Resources

Three datasets from the Changjiang Water Resources Commission of the Ministry of Water Resources

Effects of Secondary Carbonate Precipitation and Dissolution on Changjiang (Yangtze) River Chemistry and Estimates of Silicate Weathering Rates

AbstractRiverine solute chemistry has long been used to infer modern weathering fluxes and processes by assuming that river‐dissolved loads are conservative mixtures of weathering products of different lithologies. Secondary carbonate precipitation and re‐dissolution are important processes that can alter the original weathering fluxes. However, it remains less well understood how secondary carbonates affect the solute chemistry of large rivers and the estimates of silicate weathering rates. Here we report the elemental and Sr‐Mg isotopic compositions of the Changjiang (Yangtze River) water collected biweekly from May 2010 to April 2011 and use this data set to explore the influence of secondary carbonate precipitation and re‐dissolution on the Changjiang river chemistry. Variable Ca/Sr and Ca/Mg ratios but stable 87Sr/86Sr and δ26Mg are observed, which can only be explained by the precipitation and dissolution of secondary carbonates. Across a range of possible Ca/Mg ratios of the primary weathering flux, we estimate that up to 30% of the dissolved Ca carried by Changjiang was controlled by secondary carbonate precipitation and re‐dissolution. Using inverse modeling, we show that secondary carbonate precipitation and re‐dissolution have a minor influence on the calculated silicate weathering rates. Our findings provide new insights into how secondary carbonates affect water chemistry in large river systems, highlighting the role of secondary carbonate precipitation and re‐dissolution in modulating riverine dissolved fluxes in the Changjiang basin.

Can the “10-year fishing ban” rescue biodiversity of the Yangtze River?

Can the “10-year fishing ban” rescue biodiversity of the Yangtze River?

Numerical Study on the Massive Outbreak of the Ulva prolifera Green Tides in the Southwestern Yellow Sea in 2021

The most massive outbreak on record of the Ulva prolifera green tides in the southwestern Yellow Sea occurred in summer of 2021. The environmental factors were investigated based on observations and simulations. The results suggested that the significantly enhanced discharge of the Changjiang River since winter 2020–2021 was crucial for the outbreak of the Ulva prolifera green tides in the southwestern Yellow Sea, which could significantly have contributed to the nutrient enrichment off the Subei coast. Additionally, the southerly wind stress anomaly during winter 2020–2021 favored the upwind transport of Changjiang water. Numerical experiments showed that the remaining winter freshwater coming from the Changjiang River, which persisted in the Subei coast’s upper layer until spring 2021, exceeded the long-term average value by 20%. We demonstrated that these large amount of nutrient inputs, as an effective supplement, were the reason the green tides sharply emerged as an extensive outbreak in 2021. The easterly wind anomaly during spring 2021 contributed to the landing of Ulva prolifera off the Lunan coast.

Research on Conversion and Integration Framework from BIM Data to 3DGIS Scene

There are large differences between BIM and 3DGIS in model scale, data standards, information expression, etc., which brings great challenges to the conversion and integration between them. Through in-depth analysis of the current status, problems and difficulties about the integration of BIM models in 3DGIS scenes, aiming to the optimization of graphic information conversion, extraction and integration of attribute information, model light- weighting, shared scheduling, and integrated management of the entire life cycle, combined with IFC and CityGML, a framework for the transformation and integration of BIM models to 3DGIS scenes is proposed. Taking the management information system of the Changjiang Water Resources Committee as an example, after forming a preliminary three-dimensional terrain scene and building appearance model, the process of transforming and integrating a BIM building model into 3DGIS scene is discussed. The results show that the framework can effectively guide the entire process of conversion, publication, integration and application of BIM models in 3DGIS scene, and proves good practicability and operability.

生态系统服务研究在生态红线政策保护成效评估中的应用

PDF HTML阅读 XML下载 导出引用 引用提醒 生态系统服务研究在生态红线政策保护成效评估中的应用 DOI: 10.5846/stxb201801180133 作者: 作者单位: 长江水资源保护科学研究所,长江水资源保护科学研究所,长江水资源保护科学研究所,长江水资源保护科学研究所 作者简介: 通讯作者: 中图分类号: 基金项目: 国家重点研发计划课题（2017YFC0505302）；水利部预算项目（H017002） Application of ecosystem services research on a protection effectiveness evaluation of the ecological redline policy Author: Affiliation: Changjiang Water Resources Protection Institute,Changjiang Water Resources Protection Institute,Changjiang Water Resources Protection Institute,Changjiang Water Resources Protection Institute Fund Project: National Key Research and Development Program of China（2017YFC0505302）；Budget Project of Ministry of Water Resources（H017002） 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:生态保护红线政策是中国推进生态保护与建设的宏观政策，其保护成效评估是国内外关注的重大科学问题。在分析国内外生态系统服务研究进展及中国生态保护红线内涵、划定进程及管控要求的基础上，结合生态红线政策与生态系统服务研究的关联及生态系统服务研究在红线政策保护成效评估应用中面临的挑战，提出了红线政策实施效果评估的技术框架和基本思路。开展生态红线政策保护成效评估，能从科学上明确生态红线政策实施对多尺度利益相关者成本、效益的影响，为生态红线政策的综合研究提供框架和科学方法；从政策设计上，为生态红线布局进一步优化提供依据；从制度建设上，提出符合生态红线政策实施的制度框架，推动生态保护红线制度建设由理论走向实践。 Abstract:The ecological redline policy (ERP) is a key macro-level policy to manage different land-use functions in accordance with development and environmental limits. The effectiveness of the ERP is a central scientific question for both domestic and international concerns on sustainable development. In this study, we first analyzed the domestic and international progress of ecosystem services research and the connotation, demarcation process, and management requirements of China's ecological protection redline. We then proposed the technical framework and the basic ideas for an effectiveness evaluation of the ERP based on the analysis of the connection between the ERP and ecosystem services research and the challenges of the application of ecosystem services for the effectiveness evaluation of the ERP. We proposed to conduct a comprehensive policy analysis using field surveys and monitoring, remote sensing monitoring, questionnaires, and scenario simulations to evaluate the effectiveness of the ERP with the aims of 1) scientifically clarifying the impact of the ERP on the multi-scale stakeholders' costs and benefits to assess the protection efficiency of the ERP and to provide a framework and scientific method for the comprehensive study of the ERP; 2) simulating ecosystem services outcomes under alternative scenarios and provide the scientific basis for further optimization of the redline layout from a policy design standpoint; and 3) propose an institutional framework that complies with the implementation of the ERP from the point of institutional construction, to move institutional reforms from theory to practice. 参考文献 相似文献 引证文献

REMOTE SENSING APPLICATIONS WITH HIGH RELIABILITY IN CHANGJIANG WATER RESOURCE MANAGEMENT

Abstract. Remote sensing technology has been widely used in many fields. But most of the applications cannot get the information with high reliability and high accuracy in large scale, especially for the applications using automatic interpretation methods. We have designed an application-oriented technology system (PIR) composed of a series of accurate interpretation techniques,which can get over 85 % correctness in Water Resource Management from the view of photogrammetry and expert knowledge. The techniques compose of the spatial positioning techniques from the view of photogrammetry, the feature interpretation techniques from the view of expert knowledge, and the rationality analysis techniques from the view of data mining. Each interpreted polygon is accurate enough to be applied to the accuracy sensitive projects, such as the Three Gorge Project and the South - to - North Water Diversion Project. In this paper, we present several remote sensing applications with high reliability in Changjiang Water Resource Management,including water pollution investigation, illegal construction inspection, and water conservation monitoring, etc.

Response of the Changjiang (Yangtze River) water chemistry to the impoundment of Three Gorges Dam during 2010–2011

The environmental impact of Three Gorges Dam (TGD) in the Changjiang (Yangtze River) is an important topic of concern for scientific communities and the public. However, the changes in river water chemistry in response to the dam construction remain poorly constrained. This study presents the seasonal variability of all major cations and some anions in the lower Changjiang during a full hydrological year from 2010 to 2011. The concentrations of all ions, except for HCO3−, are higher after the TGD operation than before (p < 0.01), implying that the TGD has modified the river water chemistry in the mid-lower mainstream. Dissolved silicate (DSi) fluxes at Datong station thus increase slightly since the beginning of TGD impoundment. The change of mixing pattern of different water sources and alteration of hydrological and biogeochemical processes could cause the change of solute concentrations in the mid-lower Changjiang after the TGD operation. The mass balance model suggests that two factors primarily account for this increase of DSi observed at Datong: 1) an increasing loading of DSi downstream TGD due to erosion by “clean water”, and 2) an enhanced “Source” role of Lake Poyang in the mid-lower reaches. Our study would provide insights into the damming effect on river water chemistry and the complexity of a large river system facing rapid climate change and strong human activities.

Response of the Changjiang (Yangtze River) water chemistry to the impoundment of Three Gorges Dam during 2010–2011

Response of the Changjiang (Yangtze River) water chemistry to the impoundment of Three Gorges Dam during 2010–2011

长江流域水资源现状及其研究

水是生命之源、生产之要、生态之基，作为重要战略资源之一的水资源，其禀赋条件及开发利用对于长江流域乃至整个中华民族永续发展和生态文明建设具有十分重要的作用。面对生态文明建设和长江经济带建设的新形势，本文梳理了长江流域水资源及其开发利用现状和变化趋势，总结了长江水利委员会水文局近年来在长江流域水资源方面开展的研究工作，提出了未来一段时间内水资源研究的重点方向和思路，为今后在“保护中发展”长江流域水资源提供支撑。 Water is the source of life, the key of production and the basis of ecology. As one of the important stra-tegic resources, water resources’ condition and utilization play an important role in the sustainable development and ecological civilization construction of the Yangtze River basin, even the entire Chinese nation. In the face of the new situation of ecological civilization and the Yangtze River economic zone construction, the current situation and trend of development and utilization of water resources in the Yangtze River Basin are combed, and the research on the Yangtze River Basin water resources carried out by Bureau of Hydrology Changjiang Water Resources Commission in recent years is also summarized. The key direction of water resources research in the future is suggested, which will provide the support for development of water resources in protection of the Yangtze River Basin.

Teaching Content Design and Organization of Data Mining Course for Statistics Postgraduates

The data mining course is very important course for statistics postgraduates. In this paper, firstly, the theory teaching content of data mining course is introduced. It contains ten parts, that are data mining concept, the data warehouse, data pre-processing, association rules, clustering algorithm, the decision tree algorithm, the neural network, intelligent optimization algorithm, web mining, recent advances in data mining. Secondly, the experimental teaching content is introduced. It contains six experiments. Finally a teaching case is introduced. The case is about the Jingdezhen Changjiang water quality prediction which uses the neural network and intelligent optimization algorithm which are described in the theory and experiment part.

Shoal morphodynamics of the Changjiang (Yangtze) estuary: Influences from river damming, estuarine hydraulic engineering and reclamation projects

Concerns regarding estuarine shoal morphodynamics have increased worldwide because of intensive anthropogenic activities. To explore response of estuarine shoals to possible couplings of multiple artificial interferences in river basins and within estuaries, the link between the morphodynamic processes of the Nanhui Shoal (NHS), which is located along the southern margin of the Changjiang estuary, the largest estuary in Asia, and river damming, estuarine hydraulic engineering and reclamation projects, is discerned in this study. The results reveal that the NHS exhibited secular polarization during 1998–2013, with a significant accretion of 1.8×108m3 landward from the tidal ridge and an erosion of 0.3×108m3 on the seaward edge, respectively, forming a steep slope with an elevation between −2 and −3m. Meanwhile, the NHS morphodynamics could be divided into 3 stages: mild accretion with an undisturbed tidal channel during 1998–2002, strong sedimentation with a disrupted tidal channel during 2003–2008, and large-scale landward accretion with an infilled tidal channel after 2009. Moreover, the NHS's volume variations exhibited an 18-month cycle, even though an increased area of 35km2 above −2m and a decreased area of 45km2 between −2 and −5m were observed. The primary causes of theses periodic changes in the NHS's volume are determined as the fluctuating Changjiang water discharge and cyclically altered hydrodynamics of the South Passage. The Deep Waterway Project (DWP) and reclamation projects were responsible for the polarization of seaward erosion and landward accretion, respectively. Moreover, these reclamation projects dominated the staggered changes in NHS morphodynamics by inducing continuous accretion within the tidal channel. Compared to estuarine engineering, river damming induced dramatic declines in distal sediment may have played a minor role in flat changes of NHS.

Bibliometric Overview on Energy-Water Nexus Research in the Chinese Literature

With the background of water shortages and serious water pollution, issues of water involved in energy exploration and utilization have become critical problems affecting urban water usage. In order to identify the relationships of the energy-water nexus, this paper characterizes the energy-water nexus literature using a bibliometric method and based on the Chinese National Knowledge Infrastructure database platform. The results reveal that 1) Scientific outcomes in this field have increased sharply since 2003, with a slightly higher growth rate than that of general disciplines. 2) China Water Resources , Yangtze River and Express Water Resources & Hydropower Information are the dominant journals, and the main research fields include industrial economics, environmental science, and management, among other disciplines. 3) Hohai University, the Chinese Hydraulic Engineering Society, the Institute of Geographic Sciences and Natural Resources Research, and the Changjiang Water Resources Commission are the main research institutions in this field. However, the proportion of publications of these institutions is not high, which suggests that there is no institution dominating this field. 4) According to the keyword analysis, the hot spots in this field include ecological environment, sustainable development, environmental protection, climate change, etc. Energy-mining related keywords have increased over time, implying that the energy-water nexus from the perspective of the energy exploitation industry can become a key issue. At the same time, the frequency of keywords related to sustainable development has been maintained at a high level, and the studies concerned with the impacts of climate change were introduced into this field relatively late. The conclusion of this study provides a foundation for a comprehensive understanding of the current situation as well as for further research in the energy-water nexus field.

Ecosystem responses to anthropogenic and natural forcing over the last 100 years in the coastal areas of the East China Sea

Ecosystem changes of the coastal areas of the East China Sea (ECS) during the past 30 years have been characterized by increased productivity and increased occurrences of dinoflagellate red tides; both were commonly attributed to be caused by anthropogenic input of nutrients. However, climate-driven regime shifts were found in the Pacific, but they have not been observed in the ECS owing to the lack of continuous high resolution data. Hence, it is still a challenge to distinguish the influences of anthropogenic activities and climate changes on ECS shelf ecosystem. We compare phytoplankton biomarker (brassicasterol, dinosterol, and alkenones) data of five box cores from the coastal area of the ECS, which afford phytoplankton productivity and community structure records at decadal-scale resolution for the last 100 years. Phytoplankton productivity in all cores increased during the past 50 years, but community structure changes showed different trends. Relative diatom contribution revealed a decreasing trend during the past ca. 50 years in cores DH5-1 and CJ43 collected near the Changjiang Estuary, which were likely caused by increased N/Si and N/P ratios, providing conditions more favorable for dinoflagellates growth. In contrast, the relative diatom contribution increased in cores 32, 34, and DH6-3 further away and south of the Changjiang Estuary, suggesting limited influence of the Changjiang water. Instead, diatom increasing trend is likely caused by increased supply of phosphorus and silicate, as a result of larger Kuroshio intrusion flux and the corresponding strengthened coastal upwelling. Therefore, both anthropogenic activities and climate-driven coastal upwelling have contributed to increased productivities, but these two forcing mechanisms have resulted in contrasting community structure changes at different sites in the coastal area of the ECS.

The behavior of dissolved inorganic selenium in the Changjiang Estuary

To investigate the behavior of inorganic selenium species in the Changjiang Estuary, samples were taken during summer (July 2011) and winter (March 2012). Dissolved inorganic selenium (DISe) concentrations averaged 1.79nmol/L in summer and 1.24nmol/L in winter; the average selenite [Se(IV)] to selenate [Se(VI)] ratio [Se(IV)/Se(VI)] was 0.42 in summer and 0.61 in winter. The data show that Se(IV) and Se(VI) concentrations in the estuary behaved strictly conservatively during winter but non-conservatively during summer due to adsorption by suspended particulate matter (SPM) and assimilation by phytoplankton. In addition, the Se concentration distributions in the Changjiang Estuary were controlled by three water masses, each with a specific Se(IV)/Se(VI) ratio “signature”: the Changjiang Water input, the Taiwan Warm Current, and the Yellow Sea Coastal Current. The Se(IV) concentrations were related to the nitrate, silicate, and phosphate concentrations in the estuary. The DISe and Se(IV) concentrations were comparable to those found in other coastal regions and estuaries, which were considered to be natural levels.

水文资料整编系统在恢复刊印水文年鉴中的应用

在我国水文年鉴刊印史上，从1990年代起各省有十几年不等的水文资料没有刊印，为此，在保证水文年鉴刊印质量的前提下，如何对这些水文资料及时地进行恢复刊印，具有重大的现实意义；长江水利委员会水文局在2012年底，应用水文资料整编系统恢复刊印了1991年度的两册水文年鉴资料，积累了很多经验。本文针对水文资料整编系统的应用，说明其在恢复刊印水文年鉴应该把握的问题，以期为该系统的应用提供参考。 The South-Region Hydrologic Data Processing Software (SHDP) is a multi-functional data processing platform that integrates the processing/compilation of hydrologic data, information management, as well as result output as a whole. Its backstage server is the Hydrological Database (Version 4.0). The SHDP software has been so far successfully applied in hydrological departments across more than twenty provinces, cities, and autonomous regions. A problem present in the hydrologic yearbook publishing history of China is that, since the 1990s, many provincial hydrological yearbooks have not been published for dozens of years. Therefore, it is of significant practical importance to timely restore the printing of these missing materials while guaranteeing their quality. In response, the Hydrology Bureau of Changjiang Water Resources Commission has systematically restored the data of two yearbooks for 1991 using the SHDP software in 2012. In this paper, instructions for using the SHDP and the process of realizing the restoring of data in hydrologic yearbook publishing are both presented.

Occurrence and distribution of dissolved tellurium in Changjiang River estuary

With the implementation of the GEOTRACES program, the biogeochemical cycle and distribution of tellurium (Te) in marine environments are becoming increasing environmental concerns. In this study, the concentration of dissolved Te in the Changjiang (Yangtze) River estuary and nearby waters was determined in May 2009 by hydride-generation atomic fluorescence spectrometry to elucidate the abundance, dominant species, distribution, and relationship with environmental factors. Results show that: (1) dissolved Te was low owing to its low abundance in the Earth’s crust, high insolubility in water, and strong affinity to particulate matter; (2) Te(IV) and Te(VI) predominated in surface water. Te(VI) was the dominant species in bottom water, and Te(IV) was the minor species; (3) Horizontally, resulting from low phytoplankton metabolism and the weak reduction from Te(VI) to Te(IV) in the shore, Te(IV) was concentrated in the central zone instead of the coastal region. However, Te(VI) was abundant near the mouth of the Changjiang River where the Changjiang water is diluted and in the area to the south where the Taiwan Warm Current invaded. In the adsorption-desorption process, Te(IV) was negatively related to suspended particulate matter (SPM), indicating that it was adsorbed by particulate matter. While for Te(VI), the positive correlation with SPM suggested that it was desorbed from the solid phase. In the estuary, dissolved Te had a negative correlation to salinity. However, it deviated from the dilution line in high-salinity regions due to the invasion of the Taiwan Warm Current and the mineralization of organic matter. The relationship between Te(IV) and SPM nutrients indicated that it was more bioavailable and more related to phosphorus than to nitrogen. Progress in the field is slow and more research is needed to quantify the input of Te to the estuary and evaluate the biochemical role of organisms.

Using radium isotopes to estimate the residence time and the contribution of submarine groundwater discharge (SGD) in the Changjiang effluent plume, East China Sea

This paper reports the initial result of the flux of submarine groundwater discharge (SGD) into the Changjiang effluent plume (CEP). A radium mass balance model and a 224Ra/223Ra activity ratio (AR) apparent age model were applied to estimate the residence time of water above the pycnocline in the CEP. These two approaches gave similar results, yielding residence times of 5.4d and 7.0d, respectively, in the inner and outer plume zones. The nonconservative inventory of 226Ra was established in the CEP, and converted to a 226Ra flux by dividing by the water residence time and assuming steady state conditions. After subtracting the desorption of 226Ra from suspended sediment and the diffusion from the bottom sediment, the 226Ra flux from SGD was converted to a total SGD flux by dividing by the measured activity of 226Ra in local groundwater. The SGD flux in the CEP is estimated to be 0.2–1.0×109m3d−1, which is equivalent to 6–30% of the Changjiang water discharge during flood season. This large flux indicates that SGD may be another important nutrient source to the East China Sea.

Outline of The Three Gorges Dam and The Gezhouba Dam Hearing Memo at the Head Office of the Three Gorges Project Yichang, Changjiang Water Resource Commission

Outline of The Three Gorges Dam and The Gezhouba Dam Hearing Memo at the Head Office of the Three Gorges Project Yichang, Changjiang Water Resource Commission