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Copyright of Hydrogeology Journal is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Henan Province is the birthplace of Chinese civilization and one of the earliest human settlements, which means that the area has an important national cultural heritage. Traditional villages are an important facet of this cultural heritage, and studying their spatiotemporal characteristics in different periods has important theoretical and practical significance for the sustainable development and protection of cultural heritage in the region. This paper takes the traditional villages of the Yellow River basin in Henan Province that were formed before 1919 as the research object. Information on the ancient river was obtained through a literature search as well as via field research, and the important tributaries of the Yellow River in different periods were mapped using ArcGIS 10.0 software. The nearest neighbor index, kernel density estimation, standard deviation ellipse and other methods were adopted to analyze the spatiotemporal characteristics of the traditional villages. The factors that influenced the evolution of traditional villages were explored in depth by combining changes in the course of the river and water conservancy projects. The results show that the formation of traditional villages along the Yellow River in Henan Province has experienced a historical track of growth, contraction, growth and prosperity and stability. The traditional villages along the Yellow River in Henan Province generally show a clustered pattern, forming a dense concentration of traditional villages in the middle reaches of the Yellow River. The center of gravity shows a migration trend from southeast to northwest. In terms of influencing factors, the spatiotemporal evolution of the relationship between villages and their distance to water is closely related to climatic fluctuations, changes in channel, water conservancy projects and social and cultural factors. This paper deepens our understanding of the relationship between traditional village evolution and watersheds by improving the consistency between village spatial distribution and historical geography and provides a useful theoretical reference for the sustainable development of China's traditional villages. [ABSTRACT FROM AUTHOR]

For mankind's survival and development, water, energy, and food (WEF) are essential material guarantees. In China, however, the spatial distribution of WEF is seriously unbalanced and mismatched. Here, a collaborative governance mechanism that aims at nexus security needs to be urgently established. In this paper, the Yellow River Basin in China with a representative WEF system, was selected as a case. Firstly, a comprehensive framework for WEF coupling coordination was constructed, and the relationship and mechanism between them were analyzed theoretically. Then, we investigated the spatiotemporal characteristics and driving mechanisms of the coupling coordination degree (CCD) with a composite evaluation method, coupling coordination degree model, spatial statistical analysis, and multiscale geographic weighted regression. Finally, policy implications were discussed to promote the coordinated development of the WEF system. The results showed that: 1) WEF subsystems showed a significant imbalance of spatial pattern and diversity in temporal changes; 2) the CCD for the WEF system varied little and remained at moderate coordination. Areas with moderate coordination have increased, while areas with superior coordination and mild disorder have decreased. In addition, the spatial clustering phenomenon of the CCD was significant and showed obvious characteristics of polarization; and 3) the action of each factor is self-differentiated and regionally variable. For different factors, GDP per capita was of particular importance, which contributed most to the regional development's coupling coordination. For different regions, GDP per capita, average yearly precipitation, population density, and urbanization rate exhibited differences in geographical gradients in an east-west direction. The conclusion can provide references for regional resource allocation and sustainable development by enhancing WEF system utilization efficiency. [ABSTRACT FROM AUTHOR]

Firstly, based on the river health evaluation theory and starting from the integrity of the river system, the river health evaluation index system is selected. Secondly, the index systems of river health assessment including river morphology, hydrological and environmental characteristics, habitat elements and human activity characteristics are determined. Thirdly, set-pair (SPA) evaluation theory and extension were dealt with, a set-pair analysis-extension coupling model is constructed. Finally, taking Huangchuan Rive as an example, the ecological health evaluation on the river channel is carried out by using set-pair analysis-extension coupling model. The results of the comprehensive evaluation using the set-pair analysis-extension coupling method is obtained through calculation. It is proved by practice that the method of river health evaluation using the coupling model of set-pair analysis and extension theory could make full use of the data transformation and extension calculation, which shows the superiority in calculating correlation degree, and could reflect the determination and uncertainty of practical problems. It is possible to comprehensively consider all relevant factors. The paper provides a new idea for solving the relevant problems and obtains more accurate conclusion. [ABSTRACT FROM AUTHOR]

Ecological anthropology in China has a history of more than 70 years, and can be divided into four stages. The first stage was in the 1950s, which began with China's identification of minzu and socio-historical surveys of ethnic minorities. This stage was characterized by refinement and application of the Economic-Cultural Type theory from Soviet ethnography. The second stage took place in the 1980s and 1990s, when China's ecological anthropology research focused on explaining the relationship between local group culture and the environment, and how this changed in the process of modernization. Studies in this phase mainly concentrated on China's southwestern and northwestern regions, and the theoretical trends of the "adaptation model" and "the cost of development" were formed, becoming central topics. The third stage was in the first decade of the twenty-first century, when Chinese ecological anthropologists focused on the natural and social consequences of changes in the ecological environment, and stressed the importance of exploring, protecting and transforming local ecological knowledge. Ecological anthropology research flourished in Hunan, Guizhou, and Guangxi as well as in the Daxing'anling and Xiaoxing'anling mountainous regions of Northeast China. The fourth stage was in the most recent decade, when ecological anthropologists expanded their research to cover disasters, biodiversity, local social vulnerability and promotion of ecological progress, and their research areas expanded to the southeastern coast, inland river basins and traditional farming areas in the Central Plains. This paper argues that the development of ecological anthropology in China has been driven by academic consciousness rooted in local field experience, accurate understanding of the research target and changes in social situations of the era, and in-depth dialogue with Western ecological anthropological theories. At present, China's economic and social development patterns and the relationship between local people and their ecological environments are undergoing profound changes. Therefore, China's ecological anthropology should respond and adapt to these new changes through solid ethnographic surveys, take root in local field experience, and draw on the wisdom of ecological civilization development in excellent traditional Chinese culture, to become aware of new theories and carry out innovative development. [ABSTRACT FROM AUTHOR]

The Badain Jaran Desert (BJD) in China is a desert with impressive sand dunes and a groundwater situation that has attracted numerous researchers. This paper gives an overview of the mysteries of groundwater in the BJD that are exhibited as five key problems identified in previous studies. These problems relate to the origin of the groundwater, the hydrological connection between the BJD and the Heihe River Basin (HRB), the infiltration recharge, the lake-groundwater interactions, and the features of stable isotope analyses. The existing controversial analyses and hypotheses have caused debate and have hindered effective water resources management in the region. In recent years, these problems have been partly addressed by additional surveys. It has been revealed that the Quaternary sandy sediments and Neogene-Cretaceous sandstones form a thick aquifer system in the BJD. Groundwater flow at the regional scale is dominated by a significant difference in water levels between the surrounding mountains and lowlands at the western and northern edges. Discharge of groundwater from the BJD to the downstream HRB occurs according to the regional flow. Seasonal fluctuations of the water level in lakes are less than 0.5 m due to the quasi-steady groundwater discharge. The magnitude of infiltration recharge is still highly uncertain because significant limitations existed in previous studies. The evaporation effect may be the key to interpreting the anomalous negative deuterium-excess in the BJD groundwater. Further investigations are expected to reveal the hydrogeological conditions in more detail. [ABSTRACT FROM AUTHOR]

This paper investigates the effectiveness of three WUAs in the arid and semi-arid regions of northwest China, drawing upon empirical evidence collected through mixed methodologies. Results show significant discrepancies between understanding, motives and experiences regarding WUAs among different water stakeholders. These discrepancies are affected by a complex interaction of a variety of factors, including geographical locations, socio-economic and political contexts, personal experiences, knowledge gaps, incentives and value systems rather than ordinary socio-demographic variables. It has also shown that in a traditionally clientelistic society such as China social networks and the pattern of relations between different levels (either cooperative or exploitative) can be more important in participatory irrigation management than the existence of formal institutions or regulation. Furthermore, the roles of social networks on water governance are not necessarily positive, including collective exploitation, corruption especially rent-seeking and collusion. It concludes that for WUAs to be effective, they have to be context specific better understanding and strategic uses of social networks with shared water motives and goals among different stakeholders. [ABSTRACT FROM AUTHOR]

In this paper, the intensity, area and duration of future droughts in China are analyzed using the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI). The SPI and SPEI are used to evaluate the simulation ability of drought characteristics with the regional climate model COSMO-CLM (CCLM). The projected intensity and duration of future drought events are analyzed for the period 2016-2050 under three different respective concentration pathways (RCPs). The simulated and projected drought events are analyzed by applying the intensity-area-duration method. The results show that CCLM has a robust capability to simulate the average drought characteristics, while some regional disparities are not well captured, mainly the simulation of more drought events of shorter duration in Northwest China. For the future period 2016-2050, more intense dryness conditions are projected for China. An increase in evapotranspiration is found all over China, while a reduction in precipitation is apparent in the southern river basins. The increase in evapotranspiration plays an important role in the changes of future droughts over the northern river basins and southern river basins. Under RCP2.6, drought events of longer duration and with higher frequency are projected for the southwest and southeast of China. Under RCP4.5 and RCP8.5, a continuing tendency to more dry conditions is projected along a dryness band stretching from the southwest to the northeast of China. More frequent drought events of longer duration are projected in the southwestern river basins. For all future droughts, larger extents are projected, especially for events with long-term duration. The projected long-term drought events will occur more often and more severe than during the baseline period, and their central locations will likely shift towards Southeast China. The results of this study can be used to initiate and strengthen drought adaptation measures at regional and local scale, especially in the south of China. [ABSTRACT FROM AUTHOR]

The paper is concerned with the application of the Water Poverty Index (WPI) as a holistic tool to assess the Shiyang River Basin's water stress at the regional level. The basin is one of the inland river basins in China, with the degree of exploitation and utilization of water resources very high and water scarcity most severe. Appropriate indicators are needed to measure water stress for policy making and decision-making. The WPI links physical estimates of water availability with socio-economic factors associated with water scarcity. The study presents details of the methodology used, and the results show that the water stress in Minqin is the most severe in the basin, with a WPI value of 26.3, and that the water situation is the best in Jingchang with a WPI score of 66.9. In addition, measures in the basin are obtained of resources, access, capacity, use and environment. [ABSTRACT FROM AUTHOR]

Water pricing plays a crucial role in water resources management. Water shadow price is an important reference in setting water price. It was said that in practice it is almost impossible to obtain water shadow price by solving a linear programming model. In this paper we use water conservancy economy input-occupancy-output tables of the nine Chinese major river basins, and combining input-output analysis method with linear programming method we develop a linear programming model with restrictions on the final demand, total output, trade balance and water availability. We estimate the water shadow prices for industrial water and productive water for the nine Chinese major river basins in 1999 and compared these results with the real industrial water price in China in 1999. Then, for operational purposes and to estimate the shadow prices of industrial water and productive water more easily, and using a Gauss-Newton nonlinear simulation method, we present two nonlinear models that relate the ratio of the volume of water used to the total water resources volume with the shadow prices to predict shadow prices of industrial water and productive water in 2020 and 2030 in China and its nine major river basins. [ABSTRACT FROM AUTHOR]

The objective of this study is to attempt to assess the effect of green finance in reducing carbon emissions in China, analyze the transformative role of policy impact in the development of green finance markets, and investigate the impact mechanisms of how green finance affects carbon dioxide emissions. Our time frame from 2007 to 2018 is selected for the empirical study by integrating the availability of data due to the scarcity of relevant statistics in the early days of green finance. Location of this study is in China where 30 provinces are included, excluding Tibet due to severe data shortage. As for methodology, we construct a green finance evaluation index system containing five indicators by entropy weight method, choose dynamic spatial Durbin model (DSDM) for empirical research, and perform mechanism analysis of restructuring industry and greening technology as intermediary channel. Our findings demonstrate that green finance in China does significantly reduce carbon emissions, and its spatial spillover effect and long-term effect are also verified. Furthermore, green finance tends to reduce CO2 emissions through restructuring industry and greening technology. Correspondingly, policy implications are recommended. First, improving green financial market and strengthening information disclosure of green financial market are crucial to facilitate green finance development. Local governments formulate carbon emission reduction strategies focusing on space by joint conference or coordination mechanism like river head system. Lastly, a mechanism should be developed to strengthen the transformation of industrial structure and to promote greening technology. [ABSTRACT FROM AUTHOR]

Ecological base flow (EBF) is essential in maintaining the basic functions of river ecosystems, and its satisfaction evaluation and driving analysis are vital in water resource management. Most previous research has been focused on EBF target setting, and there has been a lack of analysis of river EBF satisfaction evaluation and the driving forces of noncompliance. Thus, we proposed new indicators to represent the deviation degree and analyzed the temporal and spatial characteristics of the EBF situation in China over a long time. Then, we improved the methods by incorporating some of the new indicators, which are more suitable for national EBF satisfaction evaluation. The main conclusions are as follows. 1) From 2009 to 2018, the EBF satisfaction status in China generally improved, but the overall situation was not optimistic. The Liaohe, Haihe, and Huaihe River Basins had the worst EBF satisfaction status. The poorest record of EBF protection appeared in the second quarter. The characteristics of noncompliance were expressed as the high concentration of noncompliant days in a year, high frequency of anthropogenic interruption, and significant damage depth. 2) National annual EBF compliance evaluation methods were improved by combining the new indicators with previous methods and recommended by comparing their suitability for different methods. 3) Chinese EBF noncompliant stations were identified. Seasonal water use conflict and high water withdrawal were the main driving forces of noncompliant stations. The results provide reference information for the management and protection of the EBF in China. [ABSTRACT FROM AUTHOR]

Potentially avoidable hospitalizations are associated with high and rising costs, and they have been widely considered as important performance indicators of the healthcare system, particularly in primary care. This study explored the relationship between spatial access to primary care and potentially avoidable hospitalizations of the elderly based on data from Chishui City, China, from 2014 to 2017. The enhanced two-step floating catchment area method was used to measure spatial access to care, while the relationship was estimated by a two-level logistic regression model with random effects, controlling for individual and household characteristics. We found a significantly negative association between potentially avoidable hospitalizations and spatial access to primary care, showing that the improvement of spatial access to primary care for the elderly would significantly reduce their potentially avoidable hospitalizations. Our results emphasized that the strategies to promote qualified, adequate and appropriate spatial distribution of primary care would substantially improve the healthcare system performance in China, also providing implications for other developing countries facing similar challenges. [ABSTRACT FROM AUTHOR]

In this study, the outcome serves to establish a measurement model to calculate the value of ecosystem services in Lhasa River Basin, China. Following on the principle of resource scarcity, a study paradigm is established according to the influence of natural and socio-economic location differences on the value of ecosystem services. Results show that the total value of ecosystem services in Lhasa River Basin is 104.503 billion yuan. The unit ecosystem service value of natural grassland in the lower reaches is 5.6 times and 1.07 times larger than that in the upper and middle reaches, respectively. The value of ecosystem services is clearly affected by the scarcity of ecosystem services and dependence of economic and social development on the ecosystem. The value of ecosystem services in the upper, middle, and lower reaches were 4.17%, 21.48%, and 74.35%, respectively. It is found that the value of ecosystem services in this particular region differs significantly in the upper, middle, and lower reaches of the basin. The scarcity of ecological resources has increased the value of ecosystem services, which is reflected in the highest value of ecosystem services in the middle of Lhasa River Valley and both sides of the river where population, economy, and ecological demand are relatively concentrated. According to the estimated results, this study proposes a variety of methods to improve the ecosystem service value and analysis of the ecological compensation mechanism, derived from the contribution made by ecological services. [ABSTRACT FROM AUTHOR]

A robust tree-ring-width chronology was developed from two Pinus tabulaeformis sampling sites in the source of the Fenhe River, Shanxi Province, China. Based on the tree-ring-width indices, a 157-year long Palmer Drought Severity Index (PDSI) was reconstructed, which explains 53.7% of the variance of the modeled PDSI over the common period 1957-2008. The drought periods in the study area include 1914-1931 and 1970 to the present, whereas the wet periods were 1866-1892 and 1932-1969. The drought of 1914-1931 was a severe long-lasting drought with a low inter-annual variability, and the drought of 1970-2009 was an overall long-term drought with a high inter-annual variability. The period of 1866-1892 is a continuously wet period with a low inter-annual variability and the period of 1932-1969 is an overall long-term wet period with a high inter-annual variability. The reconstructed PDSI series in the source of the Fenhe River shows synchronous variations with the regional drought/wetness indices. Spatial correlation analyses indicate that the higher correlations lie exclusively in the Fenhe River Basin. This indicates that the reconstructed PDSI has regional representativeness and can represent the drought history of the entire Fenhe River Basin to some extent. Furthermore, the reconstructed PDSI matches with the variability of the per unit yield of summer grain crops in Shanxi Province very well and they have significant correlation. From a long-term perspective the reconstructed PDSI series could supply scientific and valuable information to the water resources management and then help the sustainable development in agricultural production, economic development, and ecosystem balance. [ABSTRACT FROM AUTHOR]

In summer 2020, precipitation in many parts of China reached its maximum in the past 60 years, and southern China suffered from severe flooding, which was mainly due to the strong westward subtropical high, the enhanced east Asian summer monsoon, the development of meridional circulation, and the active cold vortex in the middle and high latitudes. We tried to apply a statistical bias correction method to improve the prediction of summer precipitation at 160 stations in China in 2020. In summer 2020, the precipitation anomaly percentages were above 40% in the Yellow River Basin and the Yangtze River Basin. Using the bias correction method, the main rain belt of the corrected summer precipitation was located in the Yangtze River's middle reaches and the Yellow River Basin, which is in line with the observations, but it does not catch the trend of more summer precipitation in the Huaihe River Basin. In addition, the corrected predicted results can basically catch the trend of dryness in South and Southwest China. Relative to the original model output, the abnormal correlation coefficient (ACC) between the corrected predictions, and the observations increased from − 0.02 to 0.30, and the prediction score (PS) increased from 67.8 to 77.4 for summer rainfall in 2020. Moreover, the bias correction method showed stable and considerable improvement for the prediction of summer precipitation in China from 2014 to 2019. Overall, this study demonstrates that the bias correction method can effectively improve the accuracy of the summer precipitation predicted results in China. [ABSTRACT FROM AUTHOR]

Precipitation fluctuations are continuously threatening the environment and may cause huge economic losses. In present study, the precipitation over China has been evaluated under five principal shared socioeconomic pathways (SSPs) scenarios during 2015–2099 based on eight CMIP6 models bias-corrected by the method of Equidistant Cumulative Distribution Functions. The results showed that (1) the simulated precipitation in China was in good agreement with observed precipitation for the eight CMIP6 models during 1961–2014, especially for the UKESM1-0-LL and MIROC6. However, the simulated annual mean precipitation has been significantly overvalued in the Southwest River basin (> 50%), while it was undervalued in the higher elevations of the Northwest River basin (< − 60%); (2) the annual mean precipitation will show a fluctuating upward trend during 2015–2099 over China under all the SSPs scenarios for the eight CMIP6 models. The rate of precipitation increase over north China will be higher than that in south China, especially in the Northwest River basin (reach 57.44% in the 2090s under the SSP5-8.5 for the ensemble mean). This increase of the precipitation in north China might alleviate the shortage of water there, but will not change the pattern of more rain in the south and less in the north; (3) in the southeastern basins, the precipitation of the multi-model ensemble (MME) and MIROC6 during 2011–2020 will be lower than that of 1961–2010 (− 6.53 to − 0.06%) under all SSPs scenarios. While the precipitation will increase obviously under all the SSPs scenarios, especially for the SSP5-8.5 scenario after the year of 2060; (4) the bias of the MME was much lower than that of individual CMIP6 models, and the bias of lower SSPs scenarios will be relatively lower. Generally, uncertainty ranges of precipitation fluctuations in north China (15.31–79.26%) will be higher than those in south China (16.06–7.55%). These findings revealed the projections and uncertainties of CMIP6 precipitation over China, which will be helpful for a better understanding of the future evolution of precipitation in China at large scale and in other regions of the world. [ABSTRACT FROM AUTHOR]

Small hydropower (SHP) is promoted as a pro-poor renewable energy source that does not have the negative social impacts of large dams. This article challenges these claims, using data from a household survey in China's upper Red River Basin. We find that SHP can fragment river systems in ways that reduce irrigation water availability, provoke changes to agricultural practices, and negatively impact river health. These social impacts of river fragmentation mainly occur in villages situated between a plant's intake and outflow. The frequency of plant water diversions due to continued generation in the dry season significantly predicts all social impacts; installed capacity of the plant and the quality of the village's irrigation infrastructure predict some impacts. Villages with strong local governance can negotiate with the plant to temporarily halt generation when irrigation water is needed, lessening social impacts. Our findings reveal that SHP plants are not as benign as they are made out to be; they must be built and managed according to community needs. [ABSTRACT FROM AUTHOR]

Copyright of Hydrogeology Journal is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Simulation of surface air temperature over China from a set of regional climate model (RCM) climate change experiments are analyzed with the focus on bias and change signal of the RCM and driving general circulation models (GCMs). The set consists of 4 simulations by the RCM of RegCM4 driven by 4 different GCMs for the period of 1979–2099 under the mid-range RCP4.5 (representative concentration pathway) scenario. Results show that for present day conditions, the RCM provides with more spatial details of the distribution and in general reduces the biases of GCM, in particular in DJF (December–January–February) and over areas with complex topography. Bias patterns show some correlation between the RCM and driving GCM in DJF but not in JJA (June–July–August). In JJA, the biases in RCM simulations show similar pattern and low sensitivity to the driving GCM, which can be attributed to the large effect of internal model physics in the season. For change signals, dominant forcings from the driving GCM are evident in the RCM simulations as shown by the magnitude, large scale spatial distribution, as well as interannual variation of the changes. The added value of RCM projection is characterized by the finer spatial detail in sub-regional (river basins) and local scale. In DJF, profound warming over the Tibetan Plateau is simulated by RCM but not GCMs. In general no clear relationships are found between the model bias and change signal, either for the driving GCMs or nested RCM. [ABSTRACT FROM AUTHOR]

Sediment source fingerprinting apportions the sources of sediment produced by water erosion by linking sampled sediment mixtures and landscape source materials using diagnostic and conservative fingerprints. Using this approach, the nature and location of active sediment sources across the catchment can be elucidated, generating information which is a key prerequisite for the design and implementation of catchment management strategies. The science of sediment source fingerprinting continues to attract much research globally, but to date, there have been relatively few fingerprinting studies in China. Here, there remain major challenges for the fingerprinting approach arising from the uniqueness of Chinese landscapes, including for instance, the complex land use configuration with highly fragmented or mosaic patches and the highly dynamic land use conversion rates, generating a need to test the physical basis for the discriminatory power and environmental behavior of both traditional and novel tracers. Future research is needed to investigate the applicability of tracer properties in different physiographic settings and to evaluate the potential strategic utility of the approach for supporting the improved management of soil and water sustainability. Here, the strategic availability of independent observation data for different components of catchment sediment budgets and well-maintained research infrastructure for plots, micro-catchments and drainage basins provides immediate opportunity for testing the approach and refining procedures. Such detailed testing across scales would be invaluable for promoting sediment source fingerprinting as both a scientific and management tool for informing soil and water conservation practices in China. [ABSTRACT FROM AUTHOR]

Copyright of Advances in Atmospheric Sciences is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Based on the outputs of 27 global climate models (GCMs) from the Coupled Model Inter-comparison Project Phase 5 (CMIP5), projected changes of extreme temperature events have been analyzed over nine river basins in China by the end of the twenty-first century relative to the reference period 1961-1990. The temporal and spatial changes and their projection uncertainty are studied using the extreme temperature indices defined by the Expert Team of Climate Change Detection and Indices (ETCCDI) under two Representative Concentration Pathways (RCPs). The model simulations predict a general increasing (decreasing) trend in warm (cold) extremes over China in the twenty-first century, with more pronounced warming trend under a higher emission scenario. The projected changes in cold and warm extremes exhibit a large difference in spatial patterns. The high-latitude and high-elevation regions of China (e.g., Continental and Southwest basins) are projected to respond more strongly to changes in cold extremes, while eastern and southern China (e.g., Yangtze River and Pearl River basins) tend to be more sensitive to the increases in warm extremes. In general, projected changes in cold indices based on minimum temperature tend to be more pronounced than in warm indices based on maximum temperature. Uncertainty analysis shows a large difference among the 27 GCMs under 2 RCP scenarios, and the uncertainty ranges tend to be larger under a higher emission scenario. Overall, the uncertainties in the emission scenarios are smaller than those from the climate models in the near future period. However, for the long-term climate projections (e.g., by the end of the twenty-first century), the projected difference under various emission scenarios tends to be larger than those by different climate models and hence can be the dominant contributor to the projection uncertainty of temperature indices. [ABSTRACT FROM AUTHOR]

Coal-floor water-inrush incidents account for a large proportion of coal mine disasters in northern China, and accurate risk assessment is crucial for safe coal production. A novel and promising assessment model for water inrush is proposed based on random forest (RF), which is a powerful intelligent machine-learning algorithm. RF has considerable advantages, including high classification accuracy and the capability to evaluate the importance of variables; in particularly, it is robust in dealing with the complicated and non-linear problems inherent in risk assessment. In this study, the proposed model is applied to Panjiayao Coal Mine, northern China. Eight factors were selected as evaluation indices according to systematic analysis of the geological conditions and a field survey of the study area. Risk assessment maps were generated based on RF, and the probabilistic neural network (PNN) model was also used for risk assessment as a comparison. The results demonstrate that the two methods are consistent in the risk assessment of water inrush at the mine, and RF shows a better performance compared to PNN with an overall accuracy higher by 6.67%. It is concluded that RF is more practicable to assess the water-inrush risk than PNN. The presented method will be helpful in avoiding water inrush and also can be extended to various engineering applications. [ABSTRACT FROM AUTHOR]

Inter-basin water transfer projects (IBWTPs) can involve basins as water donors and water receivers. In contrast to most studies on IBWTPs, which mainly impact the surface-water eco-environment, this study focuses on the impacts of an IBWTP on groundwater and its eco-environment in a water donor basin in an arid area, where surface water and groundwater are exchanged. Surface water is assumed to recharge groundwater and a groundwater numerical simulation model was constructed using MODFLOW. The model was used to quantitatively evaluate the impact of an IBWTP located in the upstream portion of Nalenggele River (the biggest river in the Qaidam basin, Northwest China). The impact involved decrease in spring flow, drawdown of groundwater, reduction in oasis area, and an increase in species replacement of oasis vegetation in the midstream and downstream of the river. Results show that the emergence sites of springs at the front of the oasis will move 2-5 km downstream, and the outflow of springs will decrease by 42 million m3/a. The maximum drawdown of groundwater level at the front of the oasis will be 3.6 m and the area across which groundwater drawdown exceeds 2.0 m will be about 59.02 km2, accounting for 2.71% of the total area of the oasis. Under such conditions, reeds will gradually be replaced by Tamarix, shrubs, and other alternative plant species. These findings have important implications for the optimization of water resource allocation and protection of the eco-environment in arid regions. [ABSTRACT FROM AUTHOR]

Elevated fluoride (F) concentration in groundwater is posing a public health risk in the Manas River Basin (MRB), Northwest China. Based on the characterization of regional groundwater flow, 90 groundwater samples from aquifers were analyzed, along with top-soil leachate and pore-water samples from aquitards. Stable oxygen (δ18O) and hydrogen isotopes, radiocarbon and hydrochemical analyses of the groundwater and pore-water samples were conducted to trace groundwater hydrological and hydrochemical processes and thereby understand the distribution and migration mechanism of F. The groundwater is recharged by meteoric precipitation through vapor condensation processes in the Tianshan Mountains. The F concentration in groundwater samples from this basin ranged from 0.11 to 48.15 mg/L (mean 2.56 mg/L). In 37 of the 90 groundwater samples, the F concentrations were above the safe level for drinking water. The F concentrations progressively increased with the residence time and well depths in the northwest of the alluvial-fluvial plain, where groundwater is overexploited for agricultural and domestic use. Positive correlations between F and sodium (Na)/calcium (Ca) indicate that the enrichment and migration of F are influenced by cation exchange processes under high-Na and alkaline pH conditions. The relationships between δ18O and F and chloride (Cl) concentrations were nonlinear due to leaching and mixing processes. This shows that vertical leaching by irrigation return flow and mixing with pore water are the dominant processes driving the migration of F in the groundwater flow system of MRB, in addition to geochemical processes. [ABSTRACT FROM AUTHOR]

Data on spatiotemporal variations in groundwater levels are crucial for understanding arsenic (As) behavior and dynamics in groundwater systems. Little is known about the influences of groundwater extraction on the transport and mobilization of As in the Hetao Basin, Inner Mongolia (China), so groundwater levels were recorded in five monitoring wells from 2011 to 2016 and in 57 irrigation wells and two multilevel wells in 2016. Results showed that groundwater level in the groundwater irrigation area had two troughs each year, induced by extensive groundwater extraction, while groundwater levels in the river-diverted (Yellow River) water irrigation area had two peaks each year, resulting from surface-water irrigation. From 2011 to 2016, groundwater levels in the groundwater irrigation area presented a decreasing trend due to the overextraction. Groundwater samples were taken for geochemical analysis each year in July from 2011 to 2016. Increasing trends were observed in groundwater total dissolved solids (TDS) and As. Owing to the reverse groundwater flow direction, the Shahai Lake acts as a new groundwater recharge source. Lake water had flushed the near-surface sediments, which contain abundant soluble components, and increased groundwater salinity. In addition, groundwater extraction induced strong downward hydraulic gradients, which led to leakage recharge from shallow high-TDS groundwater to the deep semiconfined aquifer. The most plausible explanation for similar variations among As, Fe(II) and total organic carbon (TOC) concentrations is the expected dissimilatory reduction of Fe(III) oxyhydroxides. [ABSTRACT FROM AUTHOR]

Sustainability has been one of the key criteria of effective water exploitation. Groundwater exploitation and water-table decline at Haolebaoji water source site in the Ordos basin in NW China has drawn public attention due to concerns about potential threats to ecosystems and grazing land in the area. To better investigate the impact of production wells at Haolebaoji on the water table, an adapted algorithm called the random walk on grid method (WOG) is applied to simulate the hydraulic head in the unconfined and confined aquifers. This is the first attempt to apply WOG to a real groundwater problem. The method can not only evaluate the head values but also the contributions made by each source/sink term. One is allowed to analyze the impact of source/sink terms just as if one had an analytical solution. The head values evaluated by WOG match the values derived from the software Groundwater Modeling System (GMS). It suggests that WOG is effective and applicable in a heterogeneous aquifer with respect to practical problems, and the resultant information is useful for groundwater management. [ABSTRACT FROM AUTHOR]

The modeling of changes in surface water and groundwater in the areas of inter-basin water diversion projects is quite difficult because surface water and groundwater models are run separately most of the time and the lack of sufficient data limits the application of complex surface-water/groundwater coupling models based on physical laws, especially for developing countries. In this study, a distributed surface-water and groundwater coupling model, named the distributed time variant gain model-groundwater model (DTVGM-GWM), was used to assess the influence of climate change and inter-basin water diversion on a watershed hydrological cycle. The DTVGM-GWM model can reflect the interaction processes of surface water and groundwater at basin scale. The model was applied to the Haihe River Basin (HRB) in eastern China. The possible influences of climate change and the South-to-North Water Diversion Project (SNWDP) on surface water and groundwater in the HRB were analyzed under various scenarios. The results showed that the newly constructed model DTVGM-GWM can reasonably simulate the surface and river runoff, and describe the spatiotemporal distribution characteristics of groundwater level, groundwater storage and phreatic recharge. The prediction results under different scenarios showed a decline in annual groundwater exploitation and also runoff in the HRB, while an increase of groundwater storage and groundwater level after the SNWDP’s operation. Additionally, as the project also addresses future scenarios, a slight increase is predicted in the actual evapotranspiration, soil water content and phreatic recharge. This study provides valuable insights for developing sustainable groundwater management options for the HRB. [ABSTRACT FROM AUTHOR]

Soil surface evaporation is a significant component of the hydrological cycle, occurring at the interface between the atmosphere and vadose zone, but it is affected by factors such as groundwater level, soil properties, solar radiation and others. In order to understand the soil evaporation characteristics in arid regions, a field experiment was conducted in the Ordos Basin, central China, and high accuracy sensors of soil moisture, moisture potential and temperature were installed in three field soil profiles with water-table depths (WTDs) of about 0.4, 1.4 and 2.2 m. Soil-surface-evaporation values were estimated by observed data combined with Darcy’s law. Results showed that: (1) soil-surface-evaporation rate is linked to moisture content and it is also affected by air temperature. When there is sufficient moisture in the soil profile, soil evaporation increases with rising air temperature. For a WTD larger than the height of capillary rise, the soil evaporation is related to soil moisture content, and when air temperature is above 25 °C, the soil moisture content reduces quickly and the evaporation rate lowers; (2) phreatic water contributes to soil surface evaporation under conditions in which the WTD is within the capillary fringe. This indicates that phreatic water would not participate in soil evaporation for a WTD larger than the height of capillary rise. This finding developed further the understanding of phreatic evaporation, and this study provides valuable information on recognized soil evaporation processes in the arid environment. [ABSTRACT FROM AUTHOR]

The Guanzhong Basin in central China features a booming economy and has suffered severe drought, resulting in serious groundwater depletion in the last 30 years. As a major water resource, groundwater plays a significant role in water supply. The combined impact of climate change and intensive human activities has caused a substantial decline in groundwater recharge and groundwater levels, as well as degradation of groundwater quality and associated changes in the ecosystems. Based on observational data, an integrated approach was used to assess the impact of climate change and human activities on the groundwater system and the base flow of the river basin. Methods included: river runoff records and a multivariate statistical analysis of data including historical groundwater levels and climate; hydro-chemical investigation and trend analysis of the historical hydro-chemical data; wavelet analysis of climate data; and the base flow index. The analyses indicate a clear warming trend and a decreasing trend in rainfall since the 1960s, in addition to increased human activities since the 1970s. The reduction of groundwater recharge in the past 30 years has led to a continuous depletion of groundwater levels, complex changes of the hydro-chemical environment, localized salinization, and a strong decline of the base flow to the river. It is expected that the results will contribute to a more comprehensive management plan for groundwater and the related eco-environment in the face of growing pressures from intensive human activities superimposed on climate change in this region. [ABSTRACT FROM AUTHOR]

The Dunhuang Basin, a typical inland basin in northwestern China, suffers a net loss of groundwater and the occasional disappearance of the Crescent Lake. Within this region, the groundwater/surface-water interactions are important for the sustainability of the groundwater resources. A three-dimensional transient groundwater flow model was established and calibrated using MODFLOW 2000, which was used to predict changes to these interactions once a water diversion project is completed. The simulated results indicate that introducing water from outside of the basin into the Shule and Danghe rivers could reverse the negative groundwater balance in the Basin. River-water/groundwater interactions control the groundwater hydrology, where river leakage to the groundwater in the Basin will increase from 3,114 × 104 m3/year in 2017 to 11,875 × 104 m3/year in 2021, and to 17,039 × 104 m3/year in 2036. In comparison, groundwater discharge to the rivers will decrease from 3277 × 104 m3/year in 2017 to 1857 × 104 m3/year in 2021, and to 510 × 104 m3/year by 2036; thus, the hydrology will switch from groundwater discharge to groundwater recharge after implementing the water diversion project. The simulation indicates that the increased net river infiltration due to the water diversion project will raise the water table and then effectively increasing the water level of the Crescent Lake, as the lake level is contiguous with the water table. However, the regional phreatic evaporation will be enhanced, which may intensify soil salinization in the Dunhuang Basin. These results can guide the water allocation scheme for the water diversion project to alleviate groundwater depletion and mitigate geo-environmental problem. [ABSTRACT FROM AUTHOR]

Communities are facing severe water stress due to the rapid development of agriculture and industry, climate change, as well as population growth. Climate variability has a big impact on runoff variation and it is important to understand these hydrological responses. Using a water balance model, monthly discharges of 21 climatically different catchments in China were simulated. Sensitivities of runoff to climate change were investigated by adopting hypothetical climate scenarios. Results indicate that the water balance model performs well for monthly discharge simulations of climatically different catchments with Nash-Sutcliffe coefficients >65 % and relative errors falling in the range of ±5 %. In general, runoff in arid north China are more sensitive to climate change than those in humid south China. A 1 °C rise in temperature would probably lead to 1.2-4.4 % decreases in runoff. A decrease in precipitation of 10 % would result in 9.4-17.4 % of decreases in runoff. It is essential to consider the implications of climate change in future water resources management. [ABSTRACT FROM AUTHOR]

In this study, the intensity, area, and duration of droughts in China are analyzed using the Standardized Precipitation Index (SPI). The SPI was calculated on monthly data for 530 meteorological stations in China for the period 1960-2013. The time series were analyzed for ten major hydrological regions of China, respectively. The relationships between the intensity and the area of droughts for a specific duration were analyzed by the intensity-area-duration method. The results show that areas with a significant trend in dryness can be found in a band reaching from the southwest to the northeast of China, while areas with significant trends in wetness are especially detected in the northern river basins in recent decades. In addition, for recent years (2000-2013), most of the ten major hydrological regions show opposite trends in the SPI when compared to the whole study period (1960-2013) except for the central and southwestern parts of China. This dryness/wetness trends are related to the intensity and duration of drought events, which have been stronger and lasted longer in the detected dryness band except for some northern river basins. A regional shift of drought centers is found from the northwest to the southeast within Central China. Moreover, a decreasing trend in drought area is observed, which might be related to the regional changes in precipitation pattern associated with the atmosphere-ocean interaction. Changes in the SST of the Tropical Pacific and the Tropical Indian Ocean may have resulted in frequent severe drought events of small areal extent in the central and southwestern parts of China. For the study period, the most severe droughts that covered large areas mainly occurred in the north and west of China during the mid-to-late twentieth century. However, in the early twenty-first century, the most severe droughts were located in the southwest of China covering areas less than 0.7 million km. Conclusively, drought areas show a decreasing tendency, while more intense droughts of longer duration have been experienced, especially in the south of China, in the last decades. [ABSTRACT FROM AUTHOR]

Climate change as a result of the increased greenhouse gas emissions may influence the availability of water resources in many regions on the globe. In the past decades, China has been facing severe shortage of water resources. This study focuses on the assessment of the impact of climate change on both blue and green water resources in ten large river basins in China. The blue and green water resources for these river basins were derived from the terrestrial hydrological fluxes in period 1960-2100, which were simulated with the Max Planck Institute Hydrological Model-MPI-HM. The forcing data for the hydrological model, the precipitation and temperature were obtained from three coupled Atmosphere-Ocean General Circulation Models (GCMs)-ECHAM5, IPSL and CNRM, under A2 and B1 greenhouse gas emission scenarios. The statistical bias correction method was applied on the output from the three GCMs. By using this climate model-hydrology model modeling chain, the impact of climate change on the blue and green water resources was analyzed over the ten Chinese river basins. Here, the projected changes in 2071-2100 are considered relative to 1971-2000. The projected change of monthly mean and annual mean of green water resources show the general increase for all ten river basins; among them, Inland river, Zhemin river and Zhujiang river have larger change signal than other basins. For blue water resources, increases of the annual mean are projected from November to March for Heilongjiang river, Liaohe river and Yellow river, Inland river in Northern China; and decreases are projected for Huaihe river, Zhemin river, Haihe river, Yangzi river, Southwest river, and Zhujiang river basins in Southern China. It is found that climate change has impact on both blue and green water resources over large river basins in China. The sustainable blue water resources management should take into account the different changes in both Northern and Southern China. The results show that a better management of green water resources is of importance for food and ecological securities in the context of global change. [ABSTRACT FROM AUTHOR]

To tackle China's pervasive water pollution, tremendous efforts are needed to achieve more and better information. However, resources for information collection (e.g., water quality monitoring, field experiments, etc.) are very limited for large watersheds with significant nonpoint source pollution. Thus, it is crucial to identify the priority of information acquisition. Based on the theory of value of information (VOI), a stochastic optimization approach was developed in this study to evaluate the importance of information. The approach was applied to several key polluted water bodies in China (e.g., Lake Taihu, Lake Chaohu, and Lake Dianchi). The major findings include: (1) because of the severe pollution and large uncertainty, the VOI for the targeted water bodies is substantial; (2) when the uncertainty is significant, a stricter regulation would result in a higher VOI, and therefore provide more incentives for data collection; (3) due to the interaction among different information sources, collecting multiple types of information simultaneously could be more valuable than collecting one after another; and (4) the importance of a specific type of information could vary significantly across watersheds. The proposed approach can be readily extended to more complex models and more sophisticated watershed cases. It could effectively support watershed management in China, as well as in other countries. [ABSTRACT FROM AUTHOR]

Geospatial analysis and statistical analysis are coupled in this study to determine the dynamic linkage between landscape characteristics and water quality for the years 1996, 2002, and 2007 in a subtropical coastal watershed of Southeast China. The landscape characteristics include Percent of Built (%BL), Percent of Agriculture, Percent of Natural, Patch Density and Shannon's Diversity Index (SHDI), with water quality expressed in terms of COD and NH-N. The %BL was consistently positively correlated with NH-N and COD at time three points. SHDI is significantly positively correlated with COD in 2002. The relationship between NH-N, COD and landscape variables in the wet precipitation year 2007 is stronger, with R = 0.892, than that in the dry precipitation years 1996 and 2002, which had R values of 0.712 and 0.455, respectively. Two empirical regression models constructed in this study proved more suitable for predicting COD than for predicting NH-N concentration in the unmonitored watersheds that do not have wastewater treatment plants. The calibrated regression equations have a better predictive ability over space within the wet precipitation year of 2007 than over time during the dry precipitation years from 1996 to 2002. Results show clearly that climatic variability influences the linkage of water quality-landscape characteristics and the fit of empirical regression models. [ABSTRACT FROM AUTHOR]

Copyright of Hydrogeology Journal is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Spatial and temporal characteristics of actual evapotranspiration over the Haihe River basin in China during 1960-2002 are estimated using the complementary relationship and the Thornthwaite water balance (WB) approaches. Firstly, the long-term water balance equation is used to validate and select the most suitable long-term average annual actual evapotranspiration equations for nine subbasins. Then, the most suitable method, the Pike equation, is used to calibrate parameters of the complementary relationship models and the WB model at each station. The results show that the advection aridity (AA) model more closely estimates actual evapotranspiration than does the Granger and Gray (GG) model especially considering the annual and summer evapotranspiration when compared with the WB model estimates. The results from the AA model and the WB model are then used to analyze spatial and temporal changing characteristics of the actual evapotranspiration over the basin. The analysis shows that the annual actual evapotranspirations during 1960-2002 exhibit similar decreasing trends in most parts of the Haihe River basin for the AA and WB models. Decreasing trends in annual precipitation and potential evapotranspiration, which directly affect water supply and the energy available for actual evapotranspiration respectively, jointly lead to the decrease in actual evapotranspiration in the basin. A weakening of the water cycle seems to have appeared, and as a consequence, the water supply capacity has been on the decrease, aggravating water shortage and restricting sustainable social and economic development in the region. [ABSTRACT FROM AUTHOR]

The concentrations of PAHs in the surface waters from seven river basins in China were summarized from literature published from 2000-2010. Subsequently, the risks from individual PAHs and ΣPAHs in the surface waters of China were quantified by comparing the overlap between the probability distributions of exposure concentrations with the probability distributions of toxicity data. The results show that the concentrations of 15 PAHs in the surface waters ranged from 3.09 to 38139.00 ng L, with a geometric mean of 474.93 ng L. The significantly higher concentrations of the 15 PAHs occurred in the surface waters from northern China when compared with those from southern China. The concentrations of the 15 PAHs in Chinese surface waters were higher than those in other waters worldwide. The MOS (margin of safety) values were calculated at 90th percentile values of exposure concentrations and 10th percentile values of toxicity data, with 5.75, 0.17, 2.33, 0.30, 0.57, 1.74, 1.05, and 0.11 for Ace, Ant, Flu, BaP, Flua, Nap, Phe, and Pyr, respectively. The probabilities of the individual PAH concentrations exceeding the 10th percentile value of the toxicity data were 6.06%, 2.07%, 9.51%, and 2.07% for Nap, Ace, Phe, and Flu, respectively, suggesting minimal risk to aquatic organisms; however, the probabilities of BaP, Ant, Flua, and Pyr exceeding this value were 19.49%, 25.46%, 15.15%, and 30.50%, respectively, indicating potential risks. Among the individual PAHs, the ecological risk from Pyr was the highest, followed by, in descending order of risk, Ant, Bap, Flua, Phe, Nap, Flu, and Ace. Additionally, the combined ecological risk of ΣPAH8 in Chinese surface waters was significantly higher than any that of individual PAHs alone. The MOS values in the river basins were < 1, except for the Haihe River Basin, suggesting a potential combined risk from ΣPAH8 in the other six river basins. The probabilities calculation indicate that low to high ecological risk from ΣPAH8 for all aquatic species was reported in the Liaohe River Basin (65.58%), Huaihe River Basin (57.15%), Songhua River Basin (46.49%), Pearl River Basin (38.41%), Yangtze River Basin (25.98%), Yellow River Basin (15.92%), and Haihe River Basin (5.22%). [ABSTRACT FROM AUTHOR]

Historically, paddy soils are the most valuable natural resources that produce about 90% of staple food in eastern coastal China. Dispersed patterns of rapid rural settlement expansion, or 'exurban', are recognized as key threats to the region's food security through paddy soil loss. Analyzing the process of ex-urbanization and its impact has profound implications for the sustainable development of rural China. Based on official statistics and data derived from satellite images, dynamics of rural settlement expansion and paddy soil loss were outlined for Tiaoxi watershed during China's market transition period (1994-2003). Particularly, rural settlements became more aggregated and total area expanded by 183% at an average rate of 12.3% per year for the whole watershed. Existing cores, open areas away from urban centers and areas near major transportation lines and river channels, observed the highest specialization in rural residential growth. Being closely associated with rural settlement in spatial distribution, open large paddy soil patches acted as another kind of center for rural settlement expansion within the landscape. Variations in rural settlement expansion were detected among different-tier counties, such as speed of rural settlement expansion, speed of build-ups growth per capita. These variations were closely related to social-economic development. The rapid rural settlement expansion led to a considerable loss of paddy soil, about 11% of the total amount for the whole watershed. Linear regression identified a significant relationship between paddy soil loss and rural settlement expansion. Given the social and ecological problems associated with paddy soil loss, we argue that innovative and effective planning policies as well as management programs that target at paddy soil protection should be developed and implemented in rural China. In particular, we suggest using watershed as an appropriate spatial unit for sustainable paddy soil management in this investigation. [ABSTRACT FROM AUTHOR]

In this study, the applicability of the statistical downscaling model (SDSM) in downscaling precipitation in the Yangtze River basin, China was investigated. The investigation includes the calibration of the SDSM model by using large-scale atmospheric variables encompassing NCEP/NCAR reanalysis data, the validation of the model using independent period of the NCEP/NCAR reanalysis data and the general circulation model (GCM) outputs of scenarios A2 and B2 of the HadCM3 model, and the prediction of the future regional precipitation scenarios. Selected as climate variables for downscaling were measured daily precipitation data (1961-2000) from 136 weather stations in the Yangtze River basin. The results showed that: (1) there existed good relationship between the observed and simulated precipitation during the calibration period of 1961-1990 as well as the validation period of 1991-2000. And the results of simulated monthly and seasonal precipitation were better than that of daily. The average R values between the simulated and observed monthly and seasonal precipitation for the validation period were 0.78 and 0.91 respectively for the whole basin, which showed that the SDSM had a good applicability on simulating precipitation in the Yangtze River basin. (2) Under both scenarios A2 and B2, during the prediction period of 2010-2099, the change of annual mean precipitation in the Yangtze River basin would present a trend of deficit precipitation in 2020s; insignificant changes in the 2050s; and a surplus of precipitation in the 2080s as compared to the mean values of the base period. The annual mean precipitation would increase by about 15.29% under scenario A2 and increase by about 5.33% under scenario B2 in the 2080s. The winter and autumn might be the more distinct seasons with more predicted changes of precipitation than in other seasons. And (3) there would be distinctive spatial distribution differences for the change of annual mean precipitation in the river basin, but the most of Yangtze River basin would be dominated by the increasing trend. [ABSTRACT FROM AUTHOR]

We analyzed seasonal and annual variations of the whole layer atmospheric moisture budget and precipitation during 1961–2005 and their associations with large-scale circulation in the Yangtze River basin, China. The results indicated increasing moisture budget in summer and winter, but decreasing moisture budget in spring and autumn. Positive correlations between moisture budget and precipitation illustrate tremendous impacts the moisture budget has on the precipitation changes across the Yangtze River basin. In terms of seasonal variations, significant correlations were observed between precipitation and moisture budget in spring and autumn in the upper Yangtze River basin. Besides, we also analyzed changes of geopotential height. The positive trends of the geopotential height (850 hPa) were observed in the East Asia and the negative trends in the middle and west Pacific Ocean, indicating increasing geopotential height from south to north in east Asia which largely limited the moisture propagation to north China. While decreasing meridional geopotential height from west to east along the Yangtze River basin caused more moisture propagation from the west to the east parts of the study region, which may benefit more precipitation in the middle and lower Yangtze River basin. [ABSTRACT FROM AUTHOR]

Copyright of Hydrogeology Journal is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Due to the existence of fragile karst geo-ecological environments, such as environments with extremely poor soil cover, low soil-forming velocity, and fragmentized terrain and physiognomy, as well as inappropriate and intensive land use, soil erosion is a serious problem in Guizhou Province, which is located in the centre of the karst areas of southwestern China; evaluation of soil loss and spatial distribution for conservation planning is urgently needed. This study integrated the revised universal soil loss equation (RUSLE) with a GIS to assess soil loss and identify risk erosion areas in the Maotiao River watershed of Guizhou. Current land use/cover and management practices were evaluated to determine their effects on average annual soil loss and future soil conservation practices were discussed. Data used to generate the RUSLE factors included a Landsat Thematic Mapper image (land cover), digitized topographic and soil maps, and precipitation data. The results of the study compare well with the other studies and local data, and provide useful information for decision makers and planners to take appropriate land management measures in the area. It thus indicates the RUSLE–GIS model is a useful tool for evaluating and mapping soil erosion quantitatively and spatially at a larger watershed scale in Guizhou. [ABSTRACT FROM AUTHOR]

Soil erosion is a serious environmental problem in Guizhou Province, which is located in the centre of the karst areas of southwestern China. Unfortunately, Guizhou Province suffers from a lack of financial resources to research, monitor and model soil erosion at large watershed. In order to assess the soil erosion risk, soil erosion modeling at the watershed scale are urgently needed to be undertaken. This study integrated the Revised Universal Soil Loss Equation (RUSLE) with a Geographic Information System (GIS) to estimate soil loss and identify the risk erosion areas in the Maotiao River watershed, which is a typical rural watershed in Guizhou Province. All factors used in the RUSLE were calculated for the watershed using local data. It was classified into five categories ranging from minimal risk to extreme erosion risk depending on the calculated soil erosion amount. The soil erosion map was linked to land use, elevation and slope maps to explore the relationship between soil erosion and environmental factors and identify the areas of soil erosion risk. The results can be used to advice the local government in prioritizing the areas of immediate erosion mitigation. The integrated approach allows for relatively easy, fast, and cost-effective estimation of spatially distributed soil erosion. It thus indicates that RUSLE-GIS model is a useful and efficient tool for evaluating and mapping soil erosion risk at a large watershed scale in Guizhou Province. [ABSTRACT FROM AUTHOR]

Groundwater, as a precious resource hidden underground, is an important component of the global water system. Transboundary aquifers containing substantial amount of groundwater often carry crucial ecological and social implications. Yet, it is unfortunate that transboundary aquifers have hardly been in the forefront of political and scientific discussions, and have not received due attention by policymakers. This article attempts to summarize the investigation on the eight transboundary aquifers that China shares with the neighboring countries. An overview on the groundwater resources in China, including its distribution, exploitation and challenges is also provided. Hydrogeological condition of the Heilongjiang-Amur River Basin aquifer, which is one of the eight major aquifers, is further elaborated. Cooperative activities carried out by China and Russia on monitoring and management of this aquifer are also presented. [ABSTRACT FROM AUTHOR]

Water resources are the root of life and development in arid areas like the Xinjiang Autonomous Region of China. In the Tarim Basin in Xinjiang, one of the driest places in the world, melting glaciers are the exclusive water source. Population growth, in particular in-migration, has greatly changed the ecological conditions of the Tarim River Basin in the past 2500 years. Our research aims to study the interactions between population growth and changes in water and land resources, crossing the boundaries of the different reaches in the Tarim River Basin over the past 50 years. Time series data on population changes and economic development, water volume and quality, land use and land cover changes, and prevalence of morbidity relevant to water quality are collected to study the relationship between these factors. Adopting a statistical analysis and systems dynamics approach, we quantify the effect of population growth on water use and land degradation. [ABSTRACT FROM AUTHOR]