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This paper presents an empirical analysis of regional disparities from 2000 to 2012 based on a time series of data involving 74 cities within three mega-urban regions along Yangtze River in China. Differing from previous researches on inter-provincial and coastal/interior data, this paper provides a new perspective of mega-urban regions and their cities in China. By Coefficient of Variation and Analysis of Variance the selection of three mega-urban regions along Yangtze River reveals how the mega-urban regional disparities evolve among the east, middle and west up to date in China. In terms of general trend the mega-urban regional inequalities have been decreasing ever since the year around 2005. By traditional regression modeling this paper relates the mega-urban regional inequality and the alleviation to the urbanization and its focus on mega-urban regional development. The regression shows that the evolution of intra mega-urban regions disparities is negatively influenced by the urbanization with meaningful statistical significance from 2000 to 2012. The multilevel regression is further applied based on the nested hierarchical data structure. The results indicate a complicated relationship of the urban population density of the city level, the urbanization ratio of the mega-urban region level and the urban disparities in 2012. Finally limitations and further research advice are provided. [ABSTRACT FROM AUTHOR]

The Gezhouba Reservoir (GR) and Three Gorges Reservoir (TGR) are the two largest water-storage projects in the middle reach of the Yangtze River. The impoundments of the reservoirs have changed natural flow-regimes in the river. This paper uses the Yichang Hydrological Station as a proxy for water-storage projects along the Yangtze River to assess alterations in river-flow conditions in three separate periods. The periods coincide with the start of water storage in the GR and TGR. The ecohydrological conditions in the river system are assessed based on annual discharge, water level, water temperature, and suspended-sediment concentration. More importantly, the entire analysis is done in relation to the Chinese sturgeon species, which face the danger of extinction in the Yangtze River. Based on the research reported in this paper, the impoundment of the GR and TGR increases downstream average annual water-temperature. In contrast, it decreases downstream average annual runoff, water level, and suspended-sediment concentration. The change of hydrological conditions negatively influences the spawning and hatching conditions of Chinese sturgeon. This change is the key reason that causes the fertilized rate of Chinese sturgeon eggs to decline. [ABSTRACT FROM AUTHOR]

Accurate and reliable prediction of runoff generation is necessary for flood control scheduling, water supply planning, and hydropower generation. Support vector machine (SVM), which is at the forefront of current research of regression and classification, was used in this paper to conduct monthly mean streamflow prediction. A novel heuristic optimization named bat algorithm (BA) was introduced to determine the parameters of SVM [penalty parameter (C) and kernel parameter (η)], in which the initial fitness was supposed to be equal to the initial loudness for all bats. In order to evaluate the effectiveness of the proposed approach, monthly mean streamflow from 1952 to 2011 of Yichang station in the middle reaches of the Yangtze River were trained and tested. In the meantime, the given data set was also modeled using artificial neural networks (ANN) and cross validation-based SVM. The comparison results indicate that the proposed model (bat algorithm-based SVM) is more accurate compared with both ANN and cross validation-based SVM. However, two main shortages exist, i.e., time-consuming and relatively low accuracy in the break points of continued dry (wet) years. To relieve these shortages, local optimization algorithms [e.g., differential evolution (DE) algorithm, immune algorithm (IA), and genetic algorithm (GA)] were suggested to be combined with the bat algorithm to produce the initial population. Modifications of the stochastic term of the local search were also useful. [ABSTRACT FROM AUTHOR]

Abstract: Sediment transport in suspension can represent more than 90% of a river's total annual flux of sediment. In the case of the Yangtze River, more than 99% of the sediment supplied to the sea is suspended load. Suspended sediment is thus an important component of the total sediment load, with implications for channel dynamics, landscape evolution, ecology, and human‐related activities. For hydrological management of large basins such as the Yangtze River, knowledge of the processes governing suspended sediment concentration (SSC) is essential. An analysis of the temporal variation of SSC for the Upper Yangtze basin (defined at Pingshan station) is presented here. For this purpose, a database of 50 years of concurrent discharge and SSC measurements, made by the Yangtze River Commission, is used. The analysis is made using a novel probabilistic data‐driven technique, the Generalized Pareto Uncertainty (GPU). This technique allows for the testing of several strategies of prediction and forecast applied to a time series of SSC and streamflow. Changing between local or seasonal variables to feed these strategies, we inferred that although the main driver of the SSC transport is flow (as reported by previous authors), sediment storage is also a major control. Furthermore, the maximum necessary time lag for forecasts made with the data is on the order of one week, which provides one indication of the time scale of the local processes of SSC transport in the Upper Yangtze. In this paper, limitations and data requirements of the GPU methodology are also discussed. [ABSTRACT FROM AUTHOR]

In this paper, we examine the genetic diversity, population structure and demographic history of Acrossocheilus yunnanensis inferred from four mitochondrial gene sequences. Twenty-two haplotypes were identified for A. yunnanensis. The total haplotype and nucleotide diversities of A. yunnanensis are 0.9206 and 0.024654, respectively. The monophyly of the haplotypes is supported by all phylogenetic analyses. All the haplotypes can be divided into four major lineages. The results of AMOVA and SAMOVA suggest that the best grouping pattern is to divide four groups, and that most of the variation of genetic divergence is present among these groups. The population expansion of A. yunnanensis is not supported by the analyses of population demography. Our results revealing the genetic background of A. yunnanensis will prove helpful in protecting its genetic diversity and utilizing this resource in a reasonable manner. [ABSTRACT FROM AUTHOR]

Mapping water quality change is helpful in the study of the water environment of a region. Using visual methods, interpretation of water condition and pollution issues can be intuitive and easy to understand. In this paper, we present a map to represent the spatial and temporal variation of water quality change in the Yangtze River during the period from 2006 to 2015. The calendar view was developed to explore the water quality condition and water pollutants for sections of the Yangtze River. A "W" construction was proposed to arrange the weekly water quality data in a continuous logic, and qualitative colors were designed to identify the change in major pollutants throughout the period. This map provides a promising visual analytical approach to investigate the water quality status and reveal the spatial and temporal patterns of water quality change in the Yangtze River. [ABSTRACT FROM AUTHOR]

This paper describes a record setting project in the horizontal directional drilling field involving twin pipes with a diameter of 711 mm and a length of 3,300 m. The Yangtze River is the longest river in China. The Jiangdu-Rudong gas pipeline, which is part of the Chinese gas pipeline trunk network, was constructed to transport gas from the north side to the south side of the River. The width of the river surface is 3,000 m, and the length of the crossing is 3,300 m. It was recommended by engineers that twin pipes with a diameter of 711 mm be used instead of the existing pipe with a diameter of 1,016 mm. The required depth of penetration for the crossing was determined by an analysis of 43 years of historical river scour data from 1966 to 2009 combined with a calculated result using a river scour depth formula. The recommended construction scheme included arranging two drilling rigs, laying magnetic-signal submarine cable, using the intersect method, and designing a new flat-barrel combination-type reamer. This major project was finished successfully on July 27, 2013. [ABSTRACT FROM AUTHOR]

• A comprehensive comparative empirical analysis on the container shipping network. • Supported by extensive datasets, incorporates the latest development on river basin. • Combine descriptive and explanatory analysis from interdisciplinary approaches. • A large diversity exists in how inland port systems development. The formation of barge networks on rivers and associated inland port systems is subject to a complex set of influencing factors and mechanisms. This paper aims to present a comprehensive comparative empirical analysis focusing on the container shipping (barge) network in the Yangtze and the Rhine. This analysis is supported by extensive datasets on both river basins, incorporates the latest development on both rivers and is grounded on concepts and methods coming from transport geography and economic geography. We find that a large diversity might exist in how inland port systems and related gateway seaports are dealing with cargo flows and supply chains. In view of explaining this diversity, we make a distinction between geographical/nautical aspects, macro-economic factors and institutional/governance factors. In particular, we discuss the role of institutional and governance factors in barge network development by using the concepts of selection, retention and variation. [ABSTRACT FROM AUTHOR]

The source region of the Yangtze River is in the hinterland of the Qinghai-Tibet Plateau. The source region is of great ecological significance to Qinghai-Tibet Plateau, and it is praised as the resources bank of biological species. The ecological environment in the source region of Yangtze River has deteriorated during the past decades. Based on land ecological classification and field investigation, two-phase Landsat TM/ ETM remote sensing data obtained in 1995 and 2010 were compared. The spatial changes and dynamic transfers of land ecotypes in the source region were analysed in this paper by using the analytical methods. Results show that the environmental problems in the source region have been caused by the global climate changes and human activities, coupled with the harsh natural conditions and a fragile ecological system. These changes also affect the water environment and the social-economic development of the river basins. There is an urgent need to study possible rehabilitation measures for the eco-environment of the region so as to ensure a sustainable larger river discharge. [ABSTRACT FROM AUTHOR]

The flow regime of the Yangtze River (Changjiang) has been altered to some extent by intensified human activities over the past decades, particularly dam construction. To assess the impacts of dam building on the flow regime in the Yangtze River, two of the largest reservoirs on the upper reach, i.e., the Gezhouba and Three Gorges reservoirs, have been selected as case study sites. To analyze the changes in flow regime between predam and postdam periods, the whole study period was divided into three subperiods according to the years when these two reservoirs started to store water. On the basis of the time series of daily flow discharge from four key hydrological stations, i.e., Cuntan, Yichang, Hankou, and Datong, the alterations in annual, seasonal, monthly, and daily flow regimes and water rising or falling regime in different subperiods were investigated and the driving forces were explored. The results revealed the impacts of the two reservoirs on their downstream flow regime varied with reservoir storage capacity and the distance between the target reservoir and the case study site, the Gezhouba and Three Gorges reservoirs imposed various impacts on different time scales of downstream runoff regime, and the operation of these two reservoirs altered the water rising and falling regime to some degree, which is particularly critical for the spawning of Chinese sturgeon and the four major domestic carp. The output of the paper could provide references for the assessment of impacts of dam construction on the health and stability of the Yangtze River ecosystem. [ABSTRACT FROM AUTHOR]

Runoffs in the Yellow River and Yangtze River basins, China, have been changing constantly during the last half century. In this paper, data from eight river gauging stations and 529 meteorological stations, inside and adjacent to the study basins, were analyzed and compared to quantify the hydrological processes involved, and to evaluate the role of human activities in changing river discharges. The Inverse Distance Weighted (IDW) interpolation method was used to obtain climatic data coverage from station observations. According to the runoff coefficient equation, the effect of human activities and climate can be expressed by changes in runoff coefficients and changes in precipitation, respectively. Annual runoff coefficients were calculated for the period 1950-2008, according to the correlation between respective hydrological series and regional precipitation. Annual precipitation showed no obvious trend in the upper reaches of the Yellow River but a marked downward trend in the middle and downstream reaches, with declines of 8.8 and 9.8 mm/10 a, respectively. All annual runoff series for the Yellow River basin showed a significant downward trend. Runoff declined by about 7.8 mm/10 a at Sanmenxia and 10.8 mm/10 a at Lijin. The series results indicated that an abrupt change occurred in the late 1980s to early 1990s. The trend of correlations between annual runoff and precipitation decreased significantly at the Yellow River stations, with rates ranging from 0.013/10 a to 0.019/10 a. For the hydrologic series, all precipitation series showed a downward trend in the Yangtze River basin with declines ranging from about 24.7 mm/10 a at Cuntan to 18.2 mm/10 a at Datong. Annual runoff series for the upper reaches of the Yangtze River decreased significantly, at rates ranging from 9.9 to 7.2 mm/10 a. In the middle and lower reaches, the runoff series showed no significant trend, with rates of change ranging from 2.1 to 2.9 mm/10 a. Human activities had the greatest influence on changes in the hydrological series of runoff, regardless of whether the effect was negative or positive. During 1970-2008, human activities contributed to 83% of the reduction in runoff in the Yellow River basin, and to 71% of the increase in runoff in the Yangtze River basin. Moreover, the impacts of human activities across the entire basin increased over time. In the 2000s, the impact of human activities exceeded that of climate change and was responsible for 84% of the decrease and 73% of the increase in runoff in the Yellow River and Yangtze River basins, respectively. The average annual runoff from 1980 to 2008 fell by about 97%, 83%, 83%, and 91%, compared with 1951-1969, at the Yellow River stations Lanzhou, Sanmenxia, Huayuankou and Lijin, respectively. Most of the reduction in runoff was caused by human activities. Changes in precipitation also caused reductions in runoff of about 3%, 17%, 17%, and 9% at these four stations, respectively. Falling precipitation rates were the main explanation for runoff changes at the Yangtze River stations Cuntan, Yichang, Hankou, and Datong, causing reductions in runoff of 89%, 74%, 43%, and 35%, respectively. Underlying surface changes caused decreases in runoff in the Yellow River basin and increases in runoff in the Yangtze River basin. Runoff decreased in arid areas as a result of increased water usage, but increased in humid and sub-humid areas as a result of land reclamation and mass urbanization leading to decreases in evaporation and infiltration. [ABSTRACT FROM AUTHOR]

ABSTRACT The four main Chinese carps, collectively abbreviated as MCHA, include the black carp ( Mylopharyngodon piceus), grass carp ( Ctenop haryngodon idellus), silver carp ( Hypoph thal michthys molitrix), and the big-head carp ( Aristichyths nobilis). MCHA constitutes a significant catch of China's fresh water fishery. The construction of the Gezhouba and Three Gorges Dams greatly affects the physical habitat conditions of these four main carp species. This paper presents a time-series model for the assessment of instantaneous physical conditions in MCHA habitats. The model incorporates the effects of various hydrological variables (e.g. water level fluctuation, water temperature and sediment concentration) on MCHA habitat quality. The model is tested for the Yichang-Zhijiang reaches of the Yangtze River - a suitable region for analysing the effects of dam construction on the physical conditions of MCHA habitat. The model analyses instream ecological flow (IEF) characteristics of the study area in the spawning season of MCHA. On the basis of the analysis, the min, max and optimal IEFs are 6200, 51000 and 14 500 m3/s, respectively. The model introduces an efficient method for calculating the instantaneous habitat area on the basis of IEF and other physical conditions. If properly applied, the model is an efficient tool for assessing the effects of variations in flow conditions on MCHA habitat quality. The model could also be used in real time to analyse the combined effect of ecological regulations (e.g. as induced by the Three Gorges and Gezhouba Dams) on MCHA spawning conditions. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Poyang Lake in Jiangxi Province is the largest freshwater lake in China and is historically a region of significant floods. Maximum annual lake stage and the number of severe flood events have increased during the past few decades because of levee construction that reduced the area available for floodwater storage. The most severe floods since 1950 occurred during 1954, 1973, 1983, 1995, and 1998. Each of these floods followed El Niño events that influence the Asian monsoon and that are directly linked to rainfall in the Changjiang (Yangtze River) basin. The 1954 flood was the largest ever recorded until the 1990s. That year the peak Changjiang stage at Hukou was 21.6 m, which was 1.6 m above the previous record high. The last major flood on the Changjiang was during 1998, when the peak Changjiang stage reached 22.5 m, higher than during 1954, even though peak discharge was lower. The most severe floods, including those in 1954 and 1998, require both 1) high rainfall and tributary discharge into Poyang Lake and 2) high Changjiang discharge and stage at Hukou that backflows into the lake or slows Poyang Lake drainage. Since gauging stations were established on the Changjiang, these conditions always occurred following an El Niño. [ABSTRACT FROM AUTHOR]

Purpose: The objective of this paper is to assess the regulation of the accumulation of heavy metals in the aquatic environment and different fish species. Methods: Water and fish samples were collected from upper to lower reaches of the Yangtze River. The heavy metal (Cd, Cr, Cu, Hg, Pb, Zn) concentrations in the muscle tissue of seven fishes were measured. Additionally, the relationships between heavy metal concentrations in fish tissue and fish size (length and weight), condition factor, water layer distribution, and trophic level were investigated. Results: Metal concentrations (milligrams per kilogram wet weight) were found to be distributed differently among different fish species. The highest concentrations of Cu (1.22 mg/kg) and Zn (7.55 mg/kg) were measured in Pelteobagrus fulvidraco, the highest concentrations of Cd (0.115 mg/kg) and Hg (0.0304 mg/kg) were measured in Silurus asotus, and the highest concentrations of Pb (0.811 mg/kg) and Cr (0.239 mg/kg) were measured in Carassius auratus and Cyprinus carpio. A positive relationship was found between fish size and metal level in most cases. The variance of the relationships may be the result of differences in habitat, swimming behavior, and metabolic activity. In this study, fishes living in the lower water layer and river bottom had higher metals concentrations than in upper and middle layers. Benthic carnivorous and euryphagous fish had higher metals concentrations than phytoplankton and herbivorous fish. Generally, fish caught from the lower reach had higher metals concentrations than those from the upper reach. Conclusions: Cadmium and lead concentrations in several fishes exceeded the permissible food consumption limits, this should be considered to be an important warning signal. [ABSTRACT FROM AUTHOR]

The impoundment of the Three Gorges Dam (TGD) has disturbed the hydrological regime downstream and has directly affected the relationship between the Yangtze River and Dongting Lake. To trace the realistic and potential impacts, this paper examined the changes of the channel morphology and sedimentology caused by the TGD through a field survey on the channel cross-sections and then analyzed the impact on lake water level through BP neural networks. The possible impacts on inundation patterns in lake wetlands were studied based on the lake basin DEM. The results indicate that drastic sediment decline and severe channel erosion are putting considerable pressure on the river and lake. Changing river channels are evident in some monitoring cross-sections. Dongting Lake, for the first time, changed from trapping to supplying net sediment to the Yangtze River. During the water storage periods of the TGD, the water level decreased 2.03 m in 2006 and 2.11 m in 2009 at the outlet of the lake, with extreme decreases up to 3.30 m and 3.02 m, respectively. These changes have inevitably induced alterations in the inundation patterns of the lake wetlands, which in turn have disturbed the ecological function of lake wetlands as habitats for both migratory birds and aquatic fish. The serious droughts in Dongting Lake recent years were largely connected with the above changes. Therefore, proper attention should be paid to this occurrence. [ABSTRACT FROM AUTHOR]

The vast Dongting Lake in the middle Yangtze River basin, China, was occupied by Chinese Neolithic settlements starting 10 000 years ago, and rice cultivation there is probably the earliest in the world. The numerous Neolithic settlements identified by previous archaeological surveys represent the five major Neolithic cultural stages, i.e. the Pengtoushan (9000–7900 cal. yr BP), Zaoshixiaceng (7900–6800 cal. yr BP), Daxi (6800–5500 cal. yr BP), Qujialing (5500–5000 cal. yr BP), and Shijiahe (5000–4000 cal. yr BP). Using sedimentological and geoarchaeological approaches, this paper analyses the drivers of basin-scale settlement relocation in relation to lake-level fluctuations and monsoon climate variations in the Holocene. The relocation of Neolithic sites around the lake shoreline and on the adjacent floodplain, together with radiocarbon-dated stratigraphy, clearly indicates that the shape of the lake basin was an incised and elongated valley occupied by a lake in the early Holocene, which became a broader and shallower depression in the mid to late Holocene. The established lowest habitable base of the settlements positioned on the lake shore assists reconstruction of the change in lake level from 22 m at 9000 cal. yr BP to 26 m at 5500–4000 cal. yr BP, although higher and lower lake levels occurred during the intervening cultural stages. The pollen spectra reveal a warming trend throughout the Holocene with at least four major temperature cycles, driven by monsoon variations between temperate- and warm-humid conditions. In the early Holocene the climate changed from cool-dry to warm-humid, and this played a key role in developing the earliest Pengtoushan culture in the region. Subsequent climate fluctuations fit well with the advance and retreat of the lake shore, also coevally with Neolithic site movements in the lake region. In this study we show how geoarchaeological evidence can be used in environmental reconstruction during the Holocene. [ABSTRACT FROM AUTHOR]

With population increase and economic growth, the flow regime of the Yangtze River has been altered to some extent by human activities, particularly dam construction. Dam-induced alterations in the flow regime of the Yangtze River will unavoidably influence water allocation among different water users and instream ecological water requirements may not be guaranteed during some months, particularly during phases of reservoir storing water. To assess the impacts of the Three Gorges reservoir operation on the downstream minimum instream ecological water requirements, this paper selected the Three Gorges reservoir and Yichang hydrological station below the reservoir as case study sites. On the basis of long-term time series of daily discharge data, the reservoir outflow was simulated under two water storing schemes and the degree to which the downstream minimum ecological flow was satisfied was computed. The results of this paper could provide references for the integrated management of the Yangtze River water resources and the assessment of dam-induced impacts on the Yangtze River ecosystem health. [ABSTRACT FROM AUTHOR]

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This paper presents a water quantity operation scheme to resolve series of environmental problems which some waterfront bodies are faced with, such as frequent water-level fluctuation, sediment deposition, water quality degradation, water transparency depravation, and submerged aquatic plant disappearing. Neijiang, which is a typical tide-influenced waterfront body located within the Changjiang Delta, China has been considered as the research area. A 2-D environmental and ecological model coupled with water current, water quality, suspended sediment, algae growth, and water transparency is established and validated against the field investigated data, and the model can well reflect the dynamic processes of these factors in Neijiang. Three water quantity operation modes including self-introducing, pumping, and keeping quiescence are proposed. Based on different kinds of water demand of Neijiang and the actual water exchange ability, detailed water quantity operation schemes under different hydrologic conditions are studied with the established numerical model, and the changes of some living condition factors after water operation are forecasted and evaluated. Results show that water exchange and sediment deposition in Neijiang are apparently reduced after water operation in different level years. In addition, the water quality and transparency in Neijiang can keep a good status, and the living environment is improved for submerged aquatic plant restoration. This study provides an example to resolve environmental problems, improve living conditions and keep a healthy ecosystem for similar waterfront bodies. [ABSTRACT FROM AUTHOR]

Soil erosion in the upper reaches of the Yangtze River in China is a major concern and the Central Government has initiated the Grain-for-Green Programme to convert farmland to forests and grassland to improve the environment. This paper analyses the relationship between land use and soil erosion in Zhongjiang, a typical agricultural county of Sichuan Province located in areas with severe soil erosion in the upper reaches of the Yangtze River. In our analysis, we use the ArcGIS spatial analysis module with detailed land-use data as well as data on slope conditions and soil erosion. Our research shows that the most serious soil erosion is occurring on agricultural land with a slope of 10∼25 degrees. Both farmland and permanent crops are affected by soil erosion, with almost the same percentage of soil erosion for corresponding slope conditions. Farmland with soil erosion accounts for 86⋅2 percent of the total eroded agricultural land. In the farmland with soil erosion, 22⋅5 percent have a slope of <5 degrees, 20⋅3 per cent have a slope of 5∼10 degrees, and 57⋅1 percent have a slope of >10 degrees. On gentle slopes with less than 5 degrees inclination, some 6-percent of the farmland had strong (5000∼8000 t km-2y-1) or very strong (8000∼15000 t km-2y-1)erosion. However, on steep slopes of more than 25 degrees, strong or very strong erosion was reported for more than 42 per cent of the farmland. These numbers explain why the task of soil and water conservation should be focused on the prevention of soil erosion on farmland with steep or very steep slopes. A Feasibility Index is developed and integrated socio-economic assessment on the feasibility of improving sloping farmland in 56 townships and towns is carried out. Finally, to ensure the success of the Grain-for-Green Programme, countermeasures to improve sloping farmland and control soil erosion are proposed according to the values of the Feasibility Index in the townships and towns. These include: (1) to terrace sloping farmland on a large scale and to convert farmland with a slope of over 25 degrees to forests or grassland; (2) to develop ecological agriculture combined with improving the sloping farmland and constructing prime farmland and to pay more attention to improving the technology for irrigation and cultivation techniques; and (3) to carry out soil conservation on steep-sloping farmland using suggested techniques. In addition, improving ecosystems and the inhabited environment through yard and garden construction for households is also an effective way to prevent soil erosion. [ABSTRACT FROM AUTHOR]

This paper presents major findings from a recent study aiming to systematically determine suitable river sections for local domestic water supply along the Yangtze River in Jiangsu Province, China. On the basis of analysis on the current riverbank utilization and bank stability, accessible and stable river sections in the region were selected. The water quality in these river sections was then studied using a two-dimensional unsteady flow and pollutant transport/transformation model, RBFVM-2D. The model was calibrated and verified against the hydrodynamic data, water quality data and remote sensing data collected from the river. The investigation on the pollution sources along the river identified 56 main pollution point sources. The pollution zones downstream of these point sources are the main threat for the water quality in the river. The model was used to compute the pollution zones. In particular, simulations were conducted to establish the relationship between the extent of the pollution zone and the wastewater discharge rate of the associated point source. These water quality simulation results were combined with the riverbank stability analysis to determine suitable river sections for local domestic water supply. [ABSTRACT FROM AUTHOR]

This paper explores the demographic impacts of the implementation of the "Grand Development in West China" policies and environmental rehabilitation projects in the upper reaches of the Yangtze River. It analyses the interaction between the environmental reconstruction and environment-related migration in this region. The intertwined nature of environmental, ethnic, and poverty problems not only bears negatively upon the "alleviation of poverty conducing to the accruement of wealth" of the poverty-stricken population, but also hinders the rehabilitation of the environment. It brings forth some opinions regarding improving the capacity of regional sustainable development through environmental migration. [ABSTRACT FROM AUTHOR]

Based on the sequential generalized directional distance function (SGDDF) and Metafrontier non-radial Malmquist index (MNMI), the dynamic changes, saving potential, efficiency decompositions, and influencing factors of industrial land use efficiency are analyzed. This paper is a case study on the urban agglomeration in the middle reaches of the Yangtze River focusing on the years between 2003 and 2012. The results show that (1) potential for significant improvement in industrial land use efficiency exists, and the saving potential of industrial land shows a rising trend. With the least saving potential, the Poyang Lake city group enjoys the highest efficiency. With the greatest saving potential, the efficiency in Wuhan city group is the lowest. (2) A positive catch-up effect and technological progress can be observed in industrial land use efficiency in the examined region, but the lack of technology innovators inhibits the promotion of industrial land use technology. (3) The analysis of the influencing factors shows that the relationship between per capita GDP and industrial land use efficiency follows an “N” shape. With the further economic development, industrial land use efficiency will decline slightly. Enhancing industrialization and land investment policies is thus conducive to increasing industrial land use efficiency, while industrial labor surplus and the governance of “Land Finance” have the opposite effect. Specific countermeasures to promote industrial land use efficiency are as follows: optimize industrial structure and improve labor skills; expand local industrial economy size properly to absorb surplus labor; perfect the land circulation system, and give full play to the resource allocation function of the land market; promote cross-regional flow of production factors; and strengthen regional cooperation among cities in the middle reaches of the Yangtze River. [ABSTRACT FROM AUTHOR]

The Yangtze River is one of the largest and most important rivers in the world. Over the past several decades, the natural sediment regime of the Yangtze River has been altered by the construction of dams. This paper uses multi-scale entropy analysis to ascertain the impacts of large dams on the complexity of high-frequency suspended sediment dynamics in the Yangtze River system, especially after impoundment of the Three Gorges Dam (TGD). In this study, the complexity of sediment dynamics is quantified by framing it within the context of entropy analysis of time series. Data on daily sediment loads for four stations located in the mainstem are analyzed for the past 60 years. The results indicate that dam construction has reduced the complexity of short-term (1–30 days) variation in sediment dynamics near the structures, but that complexity has actually increased farther downstream. This spatial pattern seems to reflect a filtering effect of the dams on the on the temporal pattern of sediment loads as well as decreased longitudinal connectivity of sediment transfer through the river system, resulting in downstream enhancement of the influence of local sediment inputs by tributaries on sediment dynamics. The TGD has had a substantial impact on the complexity of sediment series in the mainstem of the Yangtze River, especially after it became fully operational. This enhanced impact is attributed to the high trapping efficiency of this dam and its associated large reservoir. The sediment dynamics “signal” becomes more spatially variable after dam construction. This study demonstrates the spatial influence of dams on the high-frequency temporal complexity of sediment regimes and provides valuable information that can be used to guide environmental conservation of the Yangtze River. [ABSTRACT FROM AUTHOR]

The construction of multi-function reservoirs is important to guaranteeing the development and utilization of water and hydropower resources, but the construction of any hydrologic projects will inevitably affect the downstream flow regime that provides the driving force for riverine ecosystems. This paper therefore aims to propose a framework for assessing multi-objective reservoir operation models based on flow regime using the middle and lower Yangtze River as a case study. Using indicators of hydrologic alteration (IHA) and the histogram matching approach (HMA), critical influential factors for flow were investigated at the Yichang and Datong gauges, which are typical of the middle and lower Yangtze River. This found the magnitude of annual extreme minimum water flow rates to be the most dramatically changed indicator, with an overall degree of hydrologic alteration at the Yichang and Datong gauges of 41.98% and 34.58%, respectively. The monthly mean discharges of February and October at Yichang have been significantly changed as a result of the Three Gorges Reservoir (TGR) operation. Meanwhile, an improved range of variability approach (IRVA) was developed to obtain ideal target ranges for monthly average flow. A multi-objective ecological reservoir operations model was created for the TGR; the Non-dominated Sorting Genetic Algorithm II (NSGA-II) was applied to the model. Three typical years of wet, normal and dry years were selected, and the operation results with corresponding ideal target ranges were analyzed for the downstream Yichang and Datong cross sections. The results showed that there should be a reduction by 23.57%, 28.10% and 39.92% in the monthly mean flow of February and an increase by 34.48%, 112.36% and 52.12% in the monthly mean flow of October at Yichang cross section in wet, normal and dry years, respectively. Close attention therefore needs to be given to integrating ecological objectives with appropriate flow regimes into multi-objective operation models. [ABSTRACT FROM AUTHOR]

Several studies have indicated that glaciers in the Qinghai-Tibet plateau are thinning, resulting in reduced water supplies to major rivers such as the Yangtze, Yellow, Lancang, Indus, Ganges, Brahmaputra in China, and south Asia. Three rivers in the upstream of Yangtze River originate from glaciers around the Geladandong snow mountain group in central Tibet. Here we used elevation observations from Ice, Cloud, and land Elevation Satellite (ICESat) and reference elevations from a 3-arc-second digital elevation model (DEM) of Shuttle Radar Terrestrial Mission (SRTM), assisted with Landsat-7 images, to detect glacier elevation changes in the western (A), central (B), and eastern (C) regions of Geladandong. Robust fitting was used to determine rates of glacier elevation changes in regions with dense ICESat data, whereas a new method called rate averaging was employed to find rates in regions of low data density. The rate of elevation change was -0.158 ± 0.066 m·a-1 over 2003-2009 in the entire Geladandong and it was -0.176 ± 0.102 m·a-1 over 2003-2008 in Region C (by robust fitting). The rates in Regions A, B, and C were -0.418 ± 0.322 m·a-1 (2000-2009), -0.432 ± 0.020 m·a-1 (2000-2003), and -0.321 ± 0.139 m·a-1 (2000-2008) (by rate averaging). We used in situ hydroclimatic dataset to assess these negative rates: the glacier thinning was caused by temperature rises around Geladandong, based on the temperature records over 1979-2009, 1957-2013, and 1966-2013 at stations Tuotuohe, Wudaoliang, and Anduo. The thinning Geladandong glaciers led to increased discharges recorded at the river gauge stations Tuotuohe and Chumda over 1956-2012. An unabated Geladandong glacier melting will reduce its long-term water supply to the Yangtze River Basin, causing irreversible socioeconomic consequences and seriously degrading the ecological system of the Yangtze River Basin. [ABSTRACT FROM AUTHOR]

Channel morphology in an alluvial river usually varies due to the altered flow and sediment regime from upstream damming. This paper reports an evaluation of the dynamical changes of sedimentation and erosion in the middle and lower reaches of the Yangtze River after operation of the Three Gorges Dam (TGD). Here, we present the results from a case study of the Shashi Reach in the middle Yangtze River, which is the first sandy-bed and meandering reach downstream of TGD. Databases were constructed using a digital elevation model of channel topography based on the 1:10,000 topographic maps from the 1980s to 2012 and hydrological records from 1956 to 2013. Results indicate that the erosion in the Shashi Reach was mainly confined to the deeper channel and that it has increased since the construction of the TGD. No significant changes were observed above the bank-full level, resulting in the decrease of the width-to-depth ratio. These changes may be principally caused by variations of the seasonal distribution of flow and sediment due to the operation of the dam. In addition, results show that the cross-sectional shape change of the channel is related to the relative erodibility of the channel bed and bank material. [ABSTRACT FROM AUTHOR]

This paper examines geochemical properties of detrital magnetite, in order to link sediments in a Plio-Quaternary core taken in the delta area to their sources in the Yangtze River basin. A total of 40 sediment samples were collected from both the main river channel/tributaries and a sediment core from the Yangtze delta. The geochemical compositions of detrital magnetite in these sediments were analyzed by electron microprobe, including FeO, TiO 2 , CoO, MgO, Cr 2 O 3 , MnO, ZnO, Al 2 O 3 and V 2 O 3 . The results revealed that the detrital magnetite grains with anomalously high Cr 2 O 3 occurred exclusively in the upper reaches of the Yangtze (upstream of the Three Gorges Dam), where the E'mei Basalt block is located. This type of magnetite could therefore be considered a unique sediment proxy of the upper river basin to help identify sediment source in the delta area. Our analysis found such magnetite grains with high Cr 2 O 3 occurring throughout the core depth above 186.5 m, in contrast to the extremely low Cr 2 O 3 below this depth. The boundary between high and low Cr 2 O 3 in magnetite grains of the core sediments was dated by paleomagnetism at ca. ~ 1.2–1.0 Ma, signifying that the linkage between the Yangtze River course and the sea was before ~ 1.2–1.0 Ma. This demonstrates that the sediment provenance of the Yangtze delta has experienced a change from local to distal Yangtze River, which took place with the uplift of the Tibetan plateau and coastal subsidence during the Plio-Quaternary. [ABSTRACT FROM AUTHOR]

Summary Much has been written on the hydrology of the Yangtze River in China, especially since the construction of the Three Gorges Dam. Given the range of views in the literature on the impacts of dams and other natural and anthropogenic activities in the catchment on monthly flows, we here set out to analyse the behavior of monthly flows over the period of record 1955–2014. In the literature, the Three Gorges dam has been singled out for particular comment, mostly adverse. In this paper we analyse trend in temperature, precipitation and discharge of the Yangtze River at the monthly time scale over a period that includes the 11 years since the Three Gorges Dam came into operation. The results show that for the upper basin, there has been a marked increase in discharge in the low flow months of January to March that began abruptly in 2003 and an abrupt decrease in flow in October at the same time. Similar changes are found for discharge from the lower basin but in that case the changes have occurred gradually over the period of record. These changes are the outcome of the operation of hydroelectric and flood control dams that have been built continuously in the lower basin since 1955 while in the upper basin the building of the Three Gorges Dam began a phase of rapid dam building not seen in the lower basin. The decreased flows in the late summer and autumn are not of sufficient magnitude to cause any problems for navigation or water supply. The enhanced flows in the winter low flow period are beneficial in that they reduce the likelihood of salt water intrusions in the estuary adversely affecting the supply of freshwater to Shanghai. [ABSTRACT FROM AUTHOR]

How to balance ecosystem health and economic development is essential to study sustainability of urban ecosystems. Many methods for assessing urban sustainability have been developed, among which ecological footprint analysis (EFA) has been widely applied as a promising policy and planning tool. This paper proposed a modified EFA with the local ecological footprint being justified by adapting equivalence and yield factors in context of net primary productivity (NPP) from the Miami model. Biodiversity reserves were also incorporated using GIS technology and synthetic assessment of attributes to reflect various ecological functions. In addition, ecological footprint deficit (EFD), implying that the productive land cannot sustain current levels of consumption for a given population, was used to reveal the extent of ecological debt, while the ecological footprint variation index (EFVI) was proposed to describe the tradeoffs between real consumption and the carrying capacity of a specific region. A case study of urban areas in the middle stream of the Yangtze River Basin showed that the per capita EFD of the Wanjiang urban belt, central Poyang Lake urban agglomeration, suburban Poyang Lake urban agglomeration, Wuhan megalopolis, Jingmen–Jingzhou–Yichang urban agglomeration, central Changsha–Zhuzou–Xiangtan urban agglomeration, and suburban Changsha–Zhuzou–Xiangtan urban agglomeration increased by 64.83%, 178.05%, 214.82%, 59.08%, 71.68%, 100.62%, and 91.06% between 2000 and 2010, respectively. The local ecological footprint pressure index (EFPI) was classified into five levels. The Poyang lake urban agglomeration was found to be in a slight deficit, while all others were in a severe deficit in 2010. Calculations of EFVI also revealed that the booming urbanization occurred at great cost to the deteriorating ecosystems between 2000 and 2010. Accordingly, relevant influence factors were investigated using a forward stepwise regression method, which indicated that ecological deficit was positively correlated with GDP, population density, and emission of industrial waste, but negatively correlated with the tertiary industry. [ABSTRACT FROM AUTHOR]

Abstract: Extensive research into the changing sediment load throughout the Yangtze River (Changjiang) basin has been completed over recent years, and it provides an ongoing example of how to evaluate the consequences of natural and anthropogenic impacts on sediment processing in a very large fluvial system. This paper reviews these recent studies and critically assesses their findings regarding changes in sediment yield, load (both spatial and temporal variations), grain size, and rating curves, as well as the morphodynamic response of the channel and delta. We also discuss the factors driving these changes, including climate change, soil and water conservation measures, dam construction, and sand extraction, and consider the likely future trends in sediment load. Based on a consideration of the major outcomes of, and discrepancies between, recent studies, we conclude that sediment supply, transport, mobilization, and deposition in this large river system are complicated by the heterogeneous nature of its morphology and climate, as well as the progressive intensification of human activities. Therefore, the identification and interpretation of hydrological and sedimentological changes in the Yangtze basin can be difficult, and an in-depth study of the causal mechanisms of variations in sediment load and the impacts on the Yangtze River system is urgently required. [Copyright &y& Elsevier]

The maturation of marine phylogeography depends on integration of comparative information across different regions globally. The northwestern Pacific, characterized by unique tectonic setting, however, is still underrepresented. This study seeks to highlight its phylogeographical history based on the available population data, focusing on three seas: the East China Sea ( ECS), the South China Sea ( SCS) and the Sea of Japan ( SOJ). We first conducted a literature survey to evaluate current research efforts and then reanalysed the population structure, historical demography and genealogy for two selections of studies (namely 'the ECS category' and 'the multiple-sea category') to elucidate the evolutionary processes within and across the seas, respectively. For the ECS category, the meta-analyses revealed most studies displayed a shallow phylogeny, indicating a single origin from the sea. Significant population structure was commonplace, particularly in molluck and crustacean studies, with proportions of 89% and 80%, respectively. Nearly all studies selected showed signals of population expansion: the times estimated were closely linked to a period of ~120-140 Kya rather than the last glacial maximum. For the latter category, divergent intraspecific lineages appeared among seas and overlapped in the adjacent regions, a pattern implying each sea had served as an independent refugium during glaciations. The genetic splits, however, were estimated to arise from separate events dating from late Miocene to middle Pleistocene. As phylogeography is still in its infancy in the region, more effort is needed to test and complement the general rules abstracted here. Finally, challenges and prospects were discussed to accelerate further research. [ABSTRACT FROM AUTHOR]

Abstract: Formal safety assessment (FSA), as a structured and systematic risk evaluation methodology, has been increasingly and broadly used in the shipping industry around the world. Concerns have been raised as to navigational safety of the Yangtze River, China's largest and the world's busiest inland waterway. Over the last few decades, the throughput of ships in the Yangtze River has increased rapidly due to the national development of the Middle and Western parts of China. Accidents such as collisions, groundings, contacts, oil-spills and fires occur repeatedly, often causing serious consequences. In order to improve the navigational safety in the Yangtze River, this paper estimates the navigational risk of the Yangtze River using the FSA concept and a Bayesian network (BN) technique. The navigational risk model is established by considering both probability and consequences of accidents with respect to a risk matrix method, followed by a scenario analysis to demonstrate the application of the proposed model. [Copyright &y& Elsevier]

Abstract: This study aims to investigate whether, to what extent and how a transition toward integrated flood management has taken place in the Dongting Lake area at the middle Yangtze. Accordingly, we conducted a longitudinal research of its flood management (1949–2009). We developed an analytical framework linking regime components to two societal learning types (double and triple-loop learning) that are key to a regime transition. Our study shows that the transition toward integrated flood management has already started, but the whole regime transformation will still take time to complete, due to, for example, the not-yet-ready decision-making processes that shape the structure changes as well as the incompatibilities between what is on paper and real implementation. To understand how the regime transition took place, we investigated where and how triple-loop learning was initiated as well as how so-called “informal learning processes” has contributed to the transition of Dongting flood management. [Copyright &y& Elsevier]

Abstract: Habitat fragment owning to obstruct of dams and barriers badly affect the aquatic faunas. Many spawning sites of migration fishes are lost, and their growth and reproduction are affected. The Yangtze River with connected lakes is the most important fresh water fishery area in China. The Yangtze''s four major carp species (YFMCS) are the most typical migration fish lived in this area. They reproduce in river and grow in lake. Distributaries lies between the Yangtze River and Dongting Lake are the passages for these migration fishes. Due to the construction of dams and barriers, some original passages were out of use. Up to now, only four channels exist between the river and lake, there are Songcikou, Taipingkou and Ouchikou normally called “three outlets”, and Chenglingji inlet. Diverted Water Volume (DWV) and the Percentage of Diverted Water (PDW) through the three outlets reflect the relationship between the Yangtze River and the Dongting Lake.The variation of river-lake relation caused by dam construction, and the effect on migration fishes are discussed in this paper. The relationship of DWV and fry output in middle reach of the Yangtze river and the Dongting Lake, PDW and the percentage of the YFMCS in a total catch of fish, DWV and flux of carp fry at the Jianli station, DWV and yield of the YFMCS were analyzed. The results show that dams and barriers constructed on the Yangtze River threaten some fish species in this area, especially the migration fishes. The connectivity degree of river and lake decide the growth and reproduction of emigration fishes, the yield of the YFMCS increase by the DWV increase, and hydraulic project have important influence on reproduction of fishes. In order to reduce the ecological influence of hydropower projects, reservoir management especially in spawning season should integrate ecological demand. [Copyright &y& Elsevier]

Abstract: Eastern China’s Anatidae are globally important, occurring in large numbers and exhibiting very high diversity; however populations have declined greatly since the 1950s due to habitat loss and degradation, and poaching. To meet the urgent need for up-to-date conservation information, we conducted extensive surveys of the region’s inland and coastal wetlands to collect data on current Anatidae numbers, distributions and key sites. This paper provides information on the non-breeding distributions of 27 species and how these have changed during the last 30years, and discusses the protection status afforded to Anatidae and their habitats. About 80% of eastern China’s Anatidae occur at inland wetlands, predominantly within the Yangtze River floodplain. Current distributions of most species are different to those of the late-1970s; range contraction, range shift and northward expansion have occurred. Approximately 45% of the total Anatidae population, and high proportions of five globally threatened species populations, were located within National Nature Reserves; coverage could be increased to ca. 65% by inclusion of additional important Anatidae sites within the National Reserve system. However, a number of important issues, such as management skilling and control of land use within reserves, need to be addressed if National Nature Reserves are to provide satisfactory protection for Anatidae. It is also highly desirable that the China National List of Protected Animals include all the relevant Anatidae species on the IUCN Red List to provide a high level of protection for globally threatened species. [Copyright &y& Elsevier]

Abstract: X-ray diffraction (XRD) mineralogical and grain-size analyses indicate that inner continental shelf sediments in the East China Sea (ECS) represent a unique mixing of clays derived from the Yangtze River and silts/sands from small western Taiwanese rivers. Taiwanese (e.g., Choshui) clays (<2μm) display no smectite but the best illite crystallinity and are only distributed along southeastern Taiwan Strait. Both Yangtze and Taiwanese river clays are illite-dominated, but the poor illite crystallinity and the presence of smectite and kaolinite indicate that Taiwan Strait clays are mainly Yangtze-dominated. In contrast, medium silts (20–35μm) and very fine sands (63–90μm) in the Taiwan Strait are characterized by low feldspar/quartz, low K-feldspar/plagioclase and high kaolinite/quartz, indicating their provenance from Taiwanese rivers. Taiwanese silts and sands are introduced primarily by the way of typhoon-derived floods and transported northward by the Taiwan Warm Current during summer–fall months. Yangtze clays, in contrast, are widely dispersed southward about 1000km to the western Taiwan Strait, transported by the China Coastal Current during winter–spring months. Since most Taiwan Strait samples were collected in May 2006, clay results in this paper might only represent the winter–spring pattern of the dispersal of Yangtze sediments. [Copyright &y& Elsevier]

The Yangtze River (YR) region and cities along the river have severe deterioration of air quality due to urbanization and economic development. Black carbon (BC) has significant impacts on air quality and climate, however it is poorly characterized across the region. Here we report the first continuous measurements of BC and gaseous pollutants along the YR in wintertime, with an intensive observation period from November 21 to December 4, 2015, covering ∼7° longitude over the continent in China. The highly polluted periods (HPP) with NOx >80 μg m−3 indicated more localized emissions. At the western (longitude <118°E) and eastern (longitude >118°E) ends of the YR valley, the HPP events reduced, mostly since the western end was influenced by terrain height and regional transport, and the eastern end was influenced by easterly oceanic or westerly continental air masses. In these regions, BC core size decreased by 5%–19% during the HPP, and had modes of mass median diameter in the range 120 –180 nm, which was found to be predominately from local sources, contrasting with a more consistent mode ∼200 nm that was due to BC from mixed sources. A comparison of simultaneously measured data from the nearby monitoring stations along the river demonstrated a high consistency of PM2.5 over the river, which reflected the important regional impact on the particulate mass. This study evaluates the shipping emission and regional influence over the YR and may guide the policy maker on mitigating air pollution. Key Points: The first continuous measurements of black carbon (BC) and gaseous pollutants along the Yangtze River were conducted in wintertime covering ∼7° longitude over the continent in ChinaBC core size decreased by 5%–19% during the highly polluted periods, and had modes of mass median diameter in the range 120 –180 nm, which was found to be predominately from local sources, contrasting with a more consistent mode ∼200 nm that was due to BC from mixed sourcesThe evaluation of the shipping emission and regional influence over the Yangtze River can underpin the mitigation strategies of air pollution [ABSTRACT FROM AUTHOR]

Changes of subaqueous topography in shallow offshore water pose safety risks for embankments, navigation, and ports. This study conducted measurements of subaqueous topography between Datong and Xuliujing in the Yangtze River using a SeaBat 7125 multi-beam echo sounder, and the channel change from 1998 to 2013 was calculated using historical bathymetry data. The study revealed several important results: (1) the overall pattern of changes through the studied stretch of the river was erosion-deposition-erosion. Erosion with a volume 700×106 m3 occurred in the upper reach, deposition of about 204×106 m3 occurred in the middle reach, and erosion of about 602×106 m3 occurred in the lower reach. (2) Dunes are the most common microtopographic feature, accounting for 64.3% of the Datong to Xuliujing reach, followed by erosional topography and flat river topography, accounting for 27.6% and 6.6%, respectively. (3) Human activities have a direct impact on the development of the microtopography. For instance, the mining of sand formed holes on the surface of dunes with lengths of 20-35 m and depths of 3-5 m. We concluded that the overall trend of erosion (net erosion volume of 468×106 m3) occurred in the study area mainly because of the decreased sediment discharge following the closure of the Three Gorges Dam. However, other human activities were also impact factors of topographic change. Use of embankments and channel management reduced channel width, restricted river meandering, and exacerbated the erosion phenomenon. [ABSTRACT FROM AUTHOR]

The Yangtze drainage basin is the most densely populated and prosperous area of China; however, it is frequently threatened by floods. The Holocene flood lines of the Yangtze River have been preserved on Mt. Mufu and Swallow Cliff in north-eastern Nanjing, and they are characterised by the presence of particular colour tones and the horizontal arrangement of erosional pits and holes. Four major paleo-flood lines at altitudes of 8.51, 9.43, 10.47, and 12.84 m were identified via a field survey along the river bank. Historical literature and instrumental flood records extend the paleo-flood stage to the contemporary era and indicate that the highest flood line of 12.84 m represents a maximum limit for future floods. Besides, the flood line at 10.47 m can be regarded as a foreseeable extreme flood risk level with a recurrence interval of 100–200 years, especially considering the current circumstances of rising sea levels and decreasing flood storage capacities caused by human activities. [ABSTRACT FROM AUTHOR]

Frequency calculation for extreme flood and methods used for its uncertainty estimation are popular subjects in hydrology research. In this study, uncertainties in extreme flood estimations of the upper Yangtze River were investigated using the Delta and profile likelihood function (PLF) methods, which were used to calculate confidence intervals of key parameters of the generalized extreme value distribution and quantiles of extreme floods. Datasets of annual maximum daily flood discharge (AMDFD) from six hydrological stations located in the main stream and tributaries of the upper Yangtze River were selected in this study. The results showed that AMDFD data from the six stations followed the Weibull distribution, which has a short tail and is bounded above with an upper bound. Of the six stations, the narrowest confidence interval can be detected in the Yichang station, and the widest interval was found in the Cuntan station. Results also show that the record length and the return period are two key factors affecting the confidence interval. The width of confidence intervals decreased with the increase of record length because more information was available, while the width increased with the increase of return period. In addition, the confidence intervals of design floods were similar for both methods in a short return period. However, there was a comparatively large difference between the two methods in a long return period, because the asymmetry of the PLF curve increases with an increase in the return period. This asymmetry of the PLF method is more proficient in reflecting the uncertainty of design flood, suggesting that PLF method is more suitable for uncertainty analysis in extreme flood estimations of the upper Yangtze River Basin. [ABSTRACT FROM AUTHOR]

Wangxia rock mass was situated in Three Gorges around Yangtze River and considered to be one of largest unstable rock mass in China. The present study aims to investigate the damage of Wangxia rock mass and protect the lives of people and shipping from rockfall phenomenon. Mohr-Coulomb model in Universal Distinct Element Code was built to find out the rockfall initiation position. RocFall 4.0 program has been used to calculate horizontal location of rock end-points, maximum bounce heights, total kinetic energy, and translational velocities of the falling blocks of different weights and the input parameters were obtained by back analysis. The results show that the maximum value of bounce height and total kinetic energy is 3.63 m and 2819 kJ respectively at the horizontal location of 152.4 m, where proper protection measures should be adopted to minimize the risk of the damage of the Wangxia rock mass. Finally, the results of simulation indicate that a barrier of 5 m height and 3000 kJ absorption capacity is enough to resist the falling stones. [ABSTRACT FROM AUTHOR]

Significantly increased sedimentation rates (SRs) in lakes worldwide in recent decades due to higher inputs of silt and eutrophication have led to significant environmental problems such as lake size diminishment and degraded water quality. Many lakes in the middle and lower reaches of the Yangtze River basin (MLYB) have followed this pattern. For effective lake management, it is essential to understand the pattern and drivers of SRs in these lakes. Fourteen typical lakes in the MLYB were chosen to examine the spatiotemporal patterns of SRs and identify the drivers over different time periods. Since 1900, SRs increased from <0.2 to 0.3-0.6 g·cm-2·year-1, particularly notable during 1930-1990. Combined with climatic factors, SR correlated negatively with lake (catchment) size and abundance of aquatic vegetation, whereas other lake features including nutrient status did not contribute significantly to the variation in SRs, due to the fast decomposition processes of organic matter in shallow lakes. Detrimental land use practices especially reclamation for croplands and rapid urbanization was revealed to elevate SRs pronouncedly. We propose various management strategies aiming to maintain SR reference condition at ~0.16 ± 0.08 g·cm-2·year-1, which is analogous to the SR value between 1850 and 1900. [ABSTRACT FROM AUTHOR]

Theories that explain the governance of water, such as integrated river basin management and multilevel water governance, point to scalar configurations of power as critical determinants of success (or failure). This article explains how the scalar configurations of power in water governance mirror those of the Chinese State, and influence water governance in powerful ways. We use the case of the Yangtze River and Shanghai, a megacity in the Yangtze estuary, as examples, showing how a local jurisdiction exercises its regulatory measures against different types of transjurisdictional water pollution and how these regulatory measures mirror the fluidity (or rigidity) of power configurations in hydropolitics in China. China’s evolving water resource management institutions are as yet unable to address the scalar configurations of power in water governance. [ABSTRACT FROM PUBLISHER]

The relationship among magmatism, large-scale metallogenesis of Southeast China, and subduction of the Pacific plate has long been debated. The lower Yangtze River belt (LYRB) in the northeastern edge of Southeast China is characterized by intense late Mesozoic magmatism and associated polymetallic mineralization such as copper, gold, iron, tungsten, molybdenum, etc. The copper-related adakitic rocks (148–130 Ma) in this belt are the oldest episode of magmatism and intruded as small intermediate-acid intrusive bodies. The Huayuangong granitoids (HYG), located in the southern part of this belt, however, are copper-barren. Three granitoid samples from this pluton give zircon U–Pb ages of 126.4 ± 1.6 Ma, 125.9 ± 1.9 Ma, and 126.2 ± 1.2 Ma, respectively. The HYG has A-type affinity with metaluminous to weakly peraluminous, high FeOT/(FeOT+MgO) ratios, and high Zr+Nb+Ce+Yb contents. Meanwhile, 10 late Mesozoic mafic samples from the LYRB exhibit similar trace element characteristics to those of ‘continental arc andesite’ (CAA) and suggest an enriched lithospheric mantle source with depletion in high field strength elements (e.g. Nb, Ta, Zr, Hf, and Ti) and enrichment of large ion lithophile elements (e.g. Rb, Th, U, and Pb). Although the HYG exhibits similar Sr–Nd isotope composition with the mafic dikes, distinct whole-rock Pb isotope ratios imply that the granitoids and mafic magmas originated from heterogeneous mantle sources. Compared with coeval Baijuhuajian A-type rocks that are exposed along the Jiang–Shao fault of Southeast China, the HYG shows enriched Hf isotope ratios of zircon withεHf(t) values ranging from −4.8 to −11.1. In the Yb/TaversusY/Nb diagram, being different from the major asthenospheric mantle-origin Baijuhuajian pluton, a large range of and high Y/Nb ratios as well as high Zr contents of the HYG pluton suggest a magmatic source of mixing between the asthenospheric and enriched crustal component in the LYRB. Compared with early-stage copper-related adakitic rocks (148–130 Ma) with subduction-related affinities and high oxygen fugacity, the copper-barren HYG has with-plate A-type affinities and lower oxygen fugacity. Summarizing, the production of early-stage (i.e. subduction related) adakitic rocks followed by late-stage A-type granitoids in the LYRB is ascribed to the rollback of the Palaeo-Pacific plate beneath Southeast China and associated with asthenospheric upwelling and lithospheric thinning during the late Mesozoic era. [ABSTRACT FROM AUTHOR]

A large number of reservoirs have been built in the Yangtze River basin in the last few decades, the operation of which inevitably impacts on natural runoff. It is important to quantify the impacts of a cascade reservoir group operation on the hydrological regime in the downstream Yangtze River. The indicators of hydrologic alteration (IHA), range of variability approach (RVA), and Dundee hydrological regime assessment (DHRA) methods, which are based on five essential characteristics, i.e., magnitude, time, frequency, retardation, and rates of change, have been widely used to quantitatively analyze variation in the hydrological regime before and after the dam construction. The observed flow series at Yichang and Datong hydrological stations, located in the middle and lower reaches of the Yangtze River, respectively, are divided into pre- and post-dam construction periods by the Mann-Kendall (MK) rank correlation method. The results of the MK test reveal that the annual minimum discharge at Yichang Station has significantly changed since 2000. The analysis results of the IHA, RVA, and DHAR methods show that the hydrologic regime changed moderately after 1999 and is close to severe change after 2008 at Yichang station; and changed slightly after 1999 (the post-dam construction period) and moderately after 2008 at Datong station. A new typical year assessment method that can avoid the requirement for a long data series was proposed and compared with the RVA and DHAR methods. The results indicate that the hydrologic regime severely changed at Yichang station and moderately changed at Datong in 2014, which is consistent with the results of the above methods. This study further demonstrates that the changes are mainly reflected in the factors related to low flow such as mean discharge from January to March, minimum discharge, frequency and duration of low pulse, and so on. It is expected that further hydrological alterations will occur as the number of large cascade reservoirs constructed and operated in the Yangtze River basin increases. [ABSTRACT FROM AUTHOR]

Heavy metal pollution in China's Yangtze River basin has been of high concern. The concentrations of heavy metals (Cr, Cd, Hg, Cu, Zn, Pb, and As) in the sediment were investigated in the upper reaches of the river, China. Sediment quality guidelines (SQGs), an enrichment factor (EF), an index of geo-accumulation ( I), and potential ecological risk were used to evaluate the extent of contamination from the heavy metal concentrations in the sediment. Among the seven metals, a noticeable degree of pollution was seen only in the case of Cd and Cd posed a considerable ecological risk at some sample sites. The Pearson correlation analysis was implemented to determine the relationships among the heavy metals, and principal component analysis (PCA) was performed to determine the most common pollution sources. The elements As, Cd, Pb, and Zn were grouped together, and the anthropogenic sources of these heavy metals were closely related. The sites with higher Cd concentrations were mainly confined to the river's reach near industrial areas. Controlling the pollution sources will effectively reduce the pollutant concentrations in the sediment. [ABSTRACT FROM AUTHOR]