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Groundwater plays a critical water resources role in arid and semi-arid areas. Quantitative evaluation of groundwater recharge is crucial in hydrogeological investigations. Under the complex hydrogeological and climatic conditions in China's arid and semi-arid regions, groundwater recharge shows significant spatio-temporal heterogeneity. Although there has been much research, including hydrochemical analysis, isotope tracing, in-situ tests and numerical simulations, accurate quantitative groundwater recharge is still a great challenge. This paper reviews the progress in research on groundwater recharge in arid and semi-arid regions of China, focusing on the principles and current applications of the main techniques, as well as the achievements in nine typical arid and semi-arid regions (Tarim Basin, Junggar Basin, Shule River Basin, Heihe River Basin, Yinchuan Plain, Badain Jaran Desert, Loess Plateau, Ordos Plateau, North China Plain). The paper reveals that the chloride mass balance method is a popular method to estimate groundwater recharge rate, whereas stable isotopes and hydrochemistry analyses, as well as the joint use of both, have been widely used in the understanding of groundwater recharge processes and mechanisms in the arid and semi-arid regions of China. Numerical modeling and remote sensing technology will become important approaches to quantify large-scale groundwater recharge. It is also suggested that various estimation methods should be used in combination, in order to improve the reliability of recharge estimates. Furthermore, this review shows that the theoretical research so far still cannot meet the needs of regional development, and the paper highlights some scientific problems that need to be further explored. [ABSTRACT FROM AUTHOR]

With the continuous development of the economy and society, along with the sustained population growth, the issue of water resources carrying capacity in China has attracted increasing attention. This paper constructs a model for evaluating the provincial water resources carrying capacity in China from four dimensions: water, economy, society, and ecology. Utilizing this model, we analyze the spatiotemporal variations in water resources carrying capacity among 31 provinces in China from 2005 to 2021. Additionally, we delve into the coupling coordination and influencing factors of water resources carrying capacity. The study reveals an overall increasing trend in China's water resources carrying capacity index, with the ecological indicator exhibiting the most significant growth while the water resources sub-indicator lags behind. There are notable regional differences, with higher water resources carrying capacity observed in the eastern coastal areas and relatively lower capacity in the western regions. The ecological criterion becomes a core factor constraining water resources carrying capacity from 2005 to 2015, gradually giving way to the prominence of the social criterion since 2015. The coordination degree is relatively higher in the eastern regions, more scattered in the western regions, and relatively stable in the central regions. Based on the research findings, a series of recommendations are proposed, including strengthening environmental protection policies, optimizing water resources management mechanisms, improving water use efficiency, and promoting economic structural diversification. These suggestions aim to facilitate the sustainable development of water resources carrying capacity in China. [ABSTRACT FROM AUTHOR]

Collaboration in the prevention and control of water resource disasters is an important part of the prevention and cooperation of international river conflicts. It is also an important means to promote the de-securitization of water resources. Taking the Ili River and Lancang-Mekong River, two typical transboundary rivers in China, as the objects of analysis, this paper identifies the deficiencies in disaster early warning and emergency management of transboundary rivers in China from the perspectives of breadth, depth, and closeness. The main existing problems are summarized as follows: (J) There is no mature collaborative management mechanism for water resource disasters within the basin with an integrated platform to share data, predict disasters, formulate strategies, and communicate information. © Due to the lack of an efficient two-way disclosure system, there is little information sharing among the basin countries. © Special funds for water resource cooperation in the basin are far from enough, and they are characterized as scattered, small in amount, and intermittent. Accordingly, this paper proposes four principles for collaborative management over transboundary river disasters: information sharing, equal consultation, no significant harm, and integrated planning. Furthermore, a mechanism for disaster early warning and emergency cooperative management over transboundary rivers is proposed, including a special fund for basin water resource cooperation, an information sharing system, a disaster risk assessment system, and an emergency management decision system. Safeguard measures to support the operation of the management mechanism are put forward, including joint construction of water conservancy projects, technical assistance, interest compensation, legal system construction, fund establishment, disaster insurance, and so on. The mechanism proposed in this paper can not only make up for the deficiencies of the existing management mechanism framework of transboundary rivers in China, but also provide a reference for the implementation of disaster early warning and emergency management of other transboundary rivers. [ABSTRACT FROM AUTHOR]

The risk quotient (RQ) related to Estrone (E1), 17β–E2 (E2), Estriol (E3) and 17α-ethynylestradiol (EE2) in sediment of water resources in China was calculated using Monte Carlo Simulation (MCS) method. Fifty-four papers with 64 data-reports included in our study. The rank order of steroid hormones in sediment based on log-normal distribution in MCS was E1 (3.75 ng/g dw) > E3 (1.53 ng/g dw) > EE2 (1.38 ng/g dw) > E2 (1.17 ng/g dw). According to results, concentration of steroid hormones including E1, E2 and E3 in sediment of Erhai lake, northern Taihu lake and Dianchi river was higher than other locations. The rank order of steroid hormones based on percentage high risk (RQ > 1) was EE2 (87.00%) > E1 (70.00%) > E2 (62.99%) > E3 (11.11%). Hence, contamination control plans for steroid hormones in sediment of water resources in China should be conducted continuously. [ABSTRACT FROM AUTHOR]

China' s economy is in the midst of a crucial transition from high-speed growth to high-quality development. Strengthening the rigid constraint of water resources and curbing the disorderly expansion of high water-consuming enterprises are crucial to alleviating structural overcapacity and realizing economic development transformation from a resource-driven to an innovation-driven mode. Based on the data of A-share listed companies from 2010 to 2021, this paper explored the impact of the water resource 'fee-to-tax' policy on the over-investment of high water-consuming enterprises from the perspectives of free cash flow and technological innovation. The research results showed that levying a water resource tax could significantly inhibit the over-investment of high water-consuming enterprises, and the conclusion was still robust after a series of robustness tests (the parallel trend test, the placebo test, the PSM-DID, changing the measurement method of explained variables, excluding other policy influences, and the instrumental variable test). The mechanism analysis showed that levying a water resource tax could restrain over-investment by reducing the free cash flow of high water-consuming enterprises and stimulating technological innovation. At the same time, the restraining effect of water resource taxes on excessive investment in high water-consuming enterprises was more obvious in state-owned enterprises, enterprises with higher financing constraints, and those with higher water intensity. Based on the above conclusions, this paper holds that the water resource 'fee-to-tax' policy should be continuously improved, and the incentive mechanism of water resource tax should be improved while increasing the promotion of water consumption monitoring equipment. The flexibility of policy implementation should be strengthened, and different strategies should be adopted to guide high water-consuming enterprises with different operating conditions and investment cycles to change their production methods and investment behaviors. To implement the policy of 'giving priority to saving water' systematically, we should not only strengthen the water-saving supervision, but also raise the awareness of water users to save water voluntarily. By exploring the impact of water resource tax on the over-investment of high water-consuming enterprises, this paper attempts to deepen the understanding of the water resource 'fee-to-tax' policy, enrich the relevant literature in the field of resource regulation research, and provide a policy reference for realizing the coordinated development of economy, society, and resource carrying capacity. [ABSTRACT FROM AUTHOR]

Water resource shortages have become a national issue in China. Population growth and climate change tend to further aggravate this problem. Water rights trading is an economic means for alleviating the shortages and inefficient utilization of water resources and effectively promoting their optimal allocation. As the strategy choice of both parties of the trading directly affects the efficiency of water rights trading, this paper systematically analyzes the relevant parameters affecting the bilateral strategy choice of water rights trading based on the evolutionary game theory. First, given the impact of the market competition environment on the efficiency of water rights trading, this paper assumes that market competition is the major risk factor leading to the breakdown of negotiations; establishes the income matrix of both sides of water rights trading based on the bargaining model with the risk of breakdown; and analyzes the position, stability, and system evolution mechanism of the equilibrium point under different circumstances. Second, to emphasize the important influence of the initial strategy point on the equilibrium result of the evolutionary game, this paper describes the relative competition conditions according to the number of potential partners on both sides and further determines the initial strategy point of the game system. On this basis, the stability of the bilateral strategy choice is analyzed by using evolutionary game theory. Finally, the case of water rights trading between Zhongning City and Jingneng Power Plant is simulated and analyzed with the help of MATLAB. The results show that the trading water volume, the water resource utilization level of the transferee, and market competition have a significant impact on the transaction price, and: ① The efficiency of water rights trading will be affected when the demand of the transferee for water rights is too low and the water rights saved by the transferor cannot be effectively split. On the contrary, the sharp increase in the comprehensive compensation cost will directly raise the expected price of the transferor and will also affect the efficiency of the water rights trading. ② When the transaction price and other conditions are given, the water use efficiency of the transferee is directly proportional to the convergence speed of the water rights trading game system. ③ When the water use efficiency of the transferee of water rights is high, the price of water rights trading can be appropriately increased to realize the paid use of water resources and ensure the property income of the transferor of water rights. ④ When the transaction price and other conditions are given, the more participants in the water rights trading market, the more conducive it is to the conclusion of water rights trading. [ABSTRACT FROM AUTHOR]

General circulation models (GCMs) are developed to simulate the past climate and generate future climate predictions. In the context of global warming, their important roles in identifying possible solutions to water resources planning/management are recognized by the world. However, in actual and regional implementation, due to many factors like initial and boundary conditions, parameters and model structures and so forth, there are great variabilities and uncertainties across the future climate projections of GCMs outputs, which has attracted criticism from water resources planners. Thus, the GCMs usually must be evaluated for assessing their performances in simulating the historical observations. Currently, there are many different conclusions and opinions as to whether the optimal individual model is more advantageous or whether the combined consideration of MME works better. The purpose of this paper is to compare the advantages and disadvantages between the selection of the optimal single GCM and multi‐model ensemble (MME) based on one of the more objective selection methods called TOPSIS. The results show that the performances of GCMs in simulating precipitation and temperature in different climate subregions over China are not identical. For CMIP6 GCMs simulations, the optimal precipitation GCM is CMCC‐CM2‐SR5 for EC, MIROC6 for SC, SWC and NWC, CESM2‐WACCM for NC and NEC, and FGOALS‐g3 for QTP. As for temperature, only NESM3 and BCC‐ESM1 are the optimal GCM for QTP and NWC, respectively; in other subregions, MME is better than single GCM. In general, a simple arithmetic averaging approach employed to generate the MME model is not superior to the optimal GCM, although the error metric with the observed data is reduced, at the cost of a severe compression of the interannual variability. [ABSTRACT FROM AUTHOR]

The supply capacity of water resources, food and meat products is of great importance to the people's livelihood of a country. In recent years, although China has introduced many policies on water resources and grain production, the current situation of China's food self-sufficiency and imbalance between supply and demand of water resources has not been fundamentally changed. Food security and water security are facing a serious situation. This paper takes the water footprint as the connection point, and combines the water food meat system with mutual influence, mutual causation and dynamic feedback into a composite system. At the same time, the simulation model of the composite system is established by using system dynamics, and the dynamic simulation of water grain meat in China from 2000 to 2050 is carried out to explore the current situation and future development trend of China's water, grain and meat supply capacity. It was found that during the simulated period, the agricultural blue-green water footprint on the demand side would continue to dominate, followed by the gray water footprint. The blue water footprint on the supply side remained stable, whereas the green water footprint and the circulating water footprint showed an upward trend. According to the contemporary social and economic development and the model of water resources in China, there will be no meat shortage in the future, but issues have been found in the ability to guarantee water and food supply. The root of China's food support capability problem is excessive grain consumption due to meat production, whereas the cause of the water support capability problem is the slow development of the water conservation. Food support capability issues can be solved by regulating the meat output of livestock farming and fishery operations, reducing excess production capacity, and stabilizing the meat supply and demand. To solve the water support capability issue, China should focus on accelerating the pace of agricultural water-conservation development, improving the sewage treatment system, building rainwater-collection projects, and promoting the research and development of water recycling technology. This study provides support for optimizing the structures of the meat and grain industries and the policy formulation of the efficient use of water resources in China. [ABSTRACT FROM AUTHOR]

Exploring ways to improve the green efficiency of industry water resources (GEIWR) is an inevitable requirement for achieving harmonious and sustainable industrial development and water use. Taking the urban agglomerations in the middle reaches of the Yangtze River (UAMRYR) as an example, this paper constructed an industrial green water resource efficiency index system. Based on the slack based model (SBM), the spatiotemporal evolution characteristics of the GEIWR during 2006- 2019 were analyzed, and its spatial differentiation characteristics were investigated by exploratory spatial data analysis (ESDA), Besides, a spatial Tobit model was constructed to reveal its influencing factors. The results are as follows: (1) Temporally, the GEIWR ranged between 0.525 and 0.745 from 2006 to 2019 with an overall flat change, showing two distinct phases of change. Spatially, the difference varied markedly, with the GEIWR showing a pattern of "high in the south and low in the north" from 2006-2010 and "high in the centre and low around" from 2014-2019. (2) GEIWR global Moran's I value between 0.003 and 0.462, showing positive correlation characteristics, but the coefficient gradually decreased and the spatial correlation decreased; The local autocorrelation aggregation region changed significantly, the spatial aggregation effect was apparent before 2014, the concentration area decreased in 2019, the spatial correlation decreased, the spatial disequilibrium appeared. (3) The economic and industrial structure and the level of science and education had a significant effect on GEIWR and the economic benefits of industrial water resources showed an inverse inhibitory effect, while the natural resource endowment and degree of industrialization had no significant impact on GEIWR. Thence, when formulating water resources protection policies, the spatial distribution and influencing factors should be taken into account and the specific situation should be analyzed, to provide scientific basis for improving the GEIWR. [ABSTRACT FROM AUTHOR]

The water environment is one of the basic elements that constitute the environment. It is an important place for the survival and development of human society, and it is also the most seriously disturbed and damaged area by humans. The pollution and destruction of water environment has become one of the major environmental problems in the world today. The essence of urban water space landscape design under the concept of integrating people's ecological design is the ecological landscape design of urban water spaces, while the development of ecological landscape design in the field of urban water space landscape design is still in its infancy, and the interpretation of its concept is also different. The ecological design of the landscape reflects a new dream of human beings, a new aesthetics and value: the true cooperative and fraternal relationship between man and nature. At present, the ecological design of urban water space landscape has not put forward a more accurate concept, clear principles and standards, and a complete and systematic theoretical basis, which requires further research, discussion, and continuous practice by this generation of designers to improve it. To this end, this paper proposed a research method on the integration of water environment governance in urban and rural spaces with natural ecological landscape design. This paper mainly talked about the status quo of water environment and its network sensor algorithm research and analyzed its coverage area one by one. Then, the water quality extraction is introduced in detail. And finally, the data analysis of the Beijing river waters, the analyzer rainfall, water quality, and so on are carried out in the experimental part. It could be seen from the experimental results that there were currently 22 reclaimed water plants in six urban areas of Beijing, with a daily water treatment capacity of 4.08 million cubic meters and a sewage treatment rate of 98%. As of 2016, 440 million cubic meters of reclaimed water has been reused. With the commissioning of the new reclaimed water system, the proportion of reclaimed water in the river and lake environment will continue to increase. [ABSTRACT FROM AUTHOR]

The carbon emissions of sectors and households enabled by primary inputs have practical significance in reality. Considering the mutual effect between the industrial sector and the household, this paper firstly constructed an environmentally extended semi-closed Ghosh input–output model with an endogenized household sector to analyze the relationship between carbon emissions and the Chinese economy from the supply-side perspective. The structural decomposition analysis and the hypothetical extraction method were remodified to identify the supply-side driving effects of the changes in carbon emissions and investigate the net carbon linkage. The results show that the electricity, gas, and water supply sector was the key sector with the highest carbon emission intensity enabled by primary inputs. The household sector had an above 93% indirect effect of the enabled intensity, with its enabled intensity dropping significantly by more than 55% from 2007 to 2017. The operating surplus and mixed income caused 3214.67 Gt (34.17%) of the enabled emissions in 2017. The supply-side economic activity, measured by the value added per capita, was the main factor of the carbon emission growth, mainly attributed to the development of the manufacturing sector and the electricity, gas, and water supply sector. The emission intensity and allocation structure both brought a decrease in carbon emissions. The electricity, gas, and water supply sector and the manufacturing sector were the major sources of the supply-induced cross-sectoral input emissions, while the commercial and service sector and the household sector were the top source of supply-induced cross-sectoral output emissions. This paper sheds light on the policies of the carbon emission abatement and the adjustment of the allocation structure from the perspective of supply. [ABSTRACT FROM AUTHOR]

• Most of China still faces notable water poverty with obvious spatial variations. • Unconventional water use does not always have a positive impact on water poverty. • The impact shows an inverted U-shaped tendency as per capita GDP increases. • Sustainable water management plans should be tailored to local economy. Unconventional water serves as a bridge to water sustainability. However, many developing nations still have a long way to go in terms of unconventional water utilization. Different regional characteristics lead to different consumption capacities for unconventional water. Consequently, more unconventional water use (UWU) may not necessarily be positive for alleviating water poverty. However, there is a significant research gap in this field. This paper aims to answer three key questions: "Whether UWU consistently alleviates water poverty?" "Is this effect spatially heterogeneous?" and "What role do economic factors play in addressing water poverty?" For that, this paper focused on 30 provinces in China, with the sample period spanning from 2006 to 2021. To identify the mechanisms through which UWU alleviates water poverty, this paper employed a panel fixed-effects model using the Water Poverty Index (WPI) as the dependent variable and the square of UWU amount as an independent variable. The results indicate a non-linear impact of UWU on WPI, with the significance of impact influenced by GDP per capita (PGDP). Furthermore, threshold regressions were conducted with PGDP as the threshold variable. The results revealed a double-threshold effect of PGDP in the impact of UWU on WPI, displaying "U" or inverted "U" shape as PGDP develops: When PGDP is less than or equal to RMB 13,574, UWU demonstrates a negative effect on WPI; when PGDP ranges from RMB 13,574 to RMB 53,653, the effect turns positive; however, when PGDP exceeds RMB 53,653, the effect turns back to negative. The findings confirm that more UWU is not always better. Sustainable utilization plans of water resources must be tailored to local conditions, especially considering the unique characteristics of the regional economy. [ABSTRACT FROM AUTHOR]

As total nitrogen (TN) and total phosphorus (TP) pollution is the main source of water pollution in the Huaihe River watershed in China, it is important to understand how TN and TP pollution affect the relationship between water supply and demand. Quantifying their impacts and describing the spatiotemporal distribution of this relationships are necessary for furtherly deepening the theory of TN and TP pollution on water bodies, and this information is also particularly essential for managing water resources regionally. In this study, based on the potential water supply, the water demand and the Integrated Valuation of Ecosystem Services and Tradeoffs (In-VEST) water purification models, we estimated the TN and TP pollution from agricultural fertilizer, livestock and poultry breeding, and rural residents in the Huaihe River watershed and simulated TN and TP impacts on the relationship between water supply and demand. We found that if the impact of TN and TP pollution on water supply was not taken into account, on average, there was excess water supply in 79.20% of the watershed and excess demand in 20.80% of the rest during 1980–2018. Under the TN concentration limit, Grade-II (The water quality meets the secondary level of water body qualified in GB3838-2002, classified as Grade-II) water was the main water-supply type in 1980–2018, followed by Grade-I and Grade-III water. The total water shortage showed an inverted V-shaped trend: first increasing and then decreasing at the same period. The proportion of the water shortage of Grade-I water in the total water shortage was the largest, followed by Grade-II and Grade-III water. Areas with excess demand were located on the north bank of Wang-Beng, Yishuhe, and Huxi regions, although the water in these sub-watersheds met the water quality standards of Grade-I water. Under the TP concentration limit, Grade-II and Grade-I water were the main water-supply types. The overall water shortage trend first increased and then decreased, exhibiting an inverted V-shape from 1980 to 2018. The water shortages of Grade-I and Grade-II water showed similar inverted V-shape trend over time. Areas that met the water quality standard of Grade-I included the north banks of Wang-Beng and Huxi regions, where there was a surplus of demand. This paper suggests a way to analyze the interaction between water pollutants and the water supply-demand ratio as the example of TN and TP pollution at a watershed scale, which can broaden water pollution theory for relative water resources departments when water supply and demand will be evaluated. [ABSTRACT FROM AUTHOR]

As a particular type of alpine glacier, debris-covered glaciers are essential for local water resources and glacial disaster warnings. The Eastern Tomur Peak Region (EPTR) is the most concentrated glacier in Tien Shan Mountain, China, where the glaciers have not been studied in detail. This paper evaluates the delineation accuracy of Landsat8 OLI, Sentinel-1A, and GF images for debris-covered glaciers in the EPTR. Each image uses the most advanced delineation method for itself to minimize the error of inherent resolutions. The results show that the accuracy of these images for delineating debris-covered glaciers is very high, and the F1 scores are expressed as 96.73%, 93.55%, and 95.81%, respectively. Therefore, Landsat images were selected to analyze the area change of EPTR from 2000 to 2022 over a 5-year time scale. The results indicate that glaciers of the EPTR decreased by 19.05 km2 from 2000 to 2020, accounting for 1.9% (0.08% a−1), and debris increased by 10.8%, which validates the opinion that the presence of debris inhibits glacier melting. The most varied time was 2010–2022, but it was much less than other Tien Shan regions. The lower glacier ablation rate in this area results from the combined effect of decreased bare ice and increased debris. The main reason for the change in debris-covered glaciers is the increase in temperature. [ABSTRACT FROM AUTHOR]

The subtropical forests in China play a pivotal part in the global and regional carbon–water cycle and in regulating the climate. Ecosystem water-use efficiency (WUE) is a crucial index for understanding the trade-off between ecosystem carbon gain and water consumption. However, the underlying mechanisms of the WUE in forest ecosystems, especially the different subtropical forests, have remained unclear. In this paper, we developed a simple framework for estimating forest WUE and revealing the underlying mechanisms of forest WUE changes via a series of numerical experiments. Validated by measured WUE, the simulated WUE from our developed WUE framework showed a good performance. In addition, we found that the subtropical forest WUE experienced a significant increasing trend during 2001–2018, especially in evergreen and deciduous broadleaf forests where the increasing rate was greatest (0.027 gC kg−1 H2O year−1, p < 0.001). Further analysis indicated that the atmospheric CO2 concentration and vapor pressure deficits (VPD), rather than leaf area index (LAI), were the dominant drivers leading to the subtropical forest WUE changes. When summed for the whole subtropical forests, CO2 and VPD had an almost equal spatial impact on annual WUE change trends and accounted for 45.3% and 49.1% of the whole study area, respectively. This suggests that future forest management aiming to increase forest carbon uptake and protect water resources needs to pay more attention to the long-term impacts of climate change on forest WUE. [ABSTRACT FROM AUTHOR]

Water and fertilizer play an important role in crop growth in dryland areas. It is a necessity to improve the water use efficiency (WUE) of the crop once the water resource is limited. In northern China, where there is a wide shortage of water resources, it is therefore necessary to investigate how fertilization affects the WUE of spring maize and to quantify the effects. A total of 33 published peer-reviewed papers were collected, and a meta-analysis and random forest model analysis were performed with 364 WUE comparisons, aiming to explore the effects of fertilization on the WUE of spring maize and to clarify the optimal conditions for WUE under fertilizer management. The results showed that fertilization significantly increased the WUE of spring maize by 56.72% (P < 0.01) when compared with non-fertilization. The WUE effect under the organic–inorganic fertilizer combination (MNPK) was approximately twice as high as that under inorganic fertilizer (NPK) or organic fertilizer (M). The greatest increase in WUE occurred at 0–100 kg ha−1 of nitrogen application (NA). Under environmental conditions including 7 ≤ mean annual temperature in the test year (T) ≤ 10 °C, 400 ≤ mean annual precipitation in the test year (P) ≤ 600 mm, and mean altitude (A) > 1500 m, and soil conditions including 10 ≤ soil organic matter content (SOM) ≤ 14 g kg−1 and available phosphorus (AP) < 5 mg kg−1, the fertilization optimally enhanced the WUE of spring maize when the agronomic measures of ridge–furrow planting (RFP) and mulching film (MF) were used. The random forest model analysis indicated that the influence factors (i.e., fertilizer regimes, environmental factors, soil factors, and agronomic measures) caused 65.62% of the variation in spring maize WUE effects, while in all influence factors, fertilizer types related to fertilizer regimes caused the most variation. The initial available potassium (AK) and available nitrogen (AN) of the soil were negatively correlated to the WUE effect, indicating that fertilization imposed a better effect on the WUE of spring maize when the soil was infertile. Fertilization significantly increased the WUE of spring maize, and organic and inorganic fertilizer application provided an effective measure for the sustainable development of spring maize in northern China. After clarifying the required conditions for fertilization increasing WUE, high-efficiency water use may be achieved. [ABSTRACT FROM AUTHOR]

Due to a series of societal factors, management of small rural water resources projects in China experience management problems. Based on the management mode of small water resources projects in three representative regions of Guangdong Province, the improved TOPSIS model is applied to evaluate the performance of management mode of small water resources projects through the combination with entropy weight method. Compared with the traditional TOPSIS model concerning the evaluation object of this paper, the evaluation value formulas of optimal and worst solutions of TOPSIS method are improved. The evaluation index system takes into account the coverage, hierarchy and systematization of indicators, and maintains a management mode with high environmental adaptability, so that the continuous operation of management mode can guaranteed. The results show that the management mode of water user association is most suitable for the development of small water resources projects in Guangdong Province. [ABSTRACT FROM AUTHOR]

Analyzing the spatial agglomeration characteristics and local spatial structure stability of the inflow and outflow areas of water resources on the basis of quantifying the flow network of water resources can provide theoretical support for formulating safer and more reasonable water resource regulation policies. This paper used the multi-regional input-output model (MRIO) and the exploratory spatiotemporal data analysis method (ESTDA) to calculate the inflow and outflow water footprints of 30 provinces in China from 2002 to 2017, and analyzed China' s water resource flow pattern as well as the spatial and temporal evolution characteristics of the spatial agglomeration patterns of the inflow and outflow water footprints. The results showed that: ① The local water footprints accounted for the largest proportion of the total water footprints and showed a steady growth trend, and the inflow and outflow water footprints had an upward-downward trend from 2002 to 2017. ② From 2002 to 2012, the total number of high-level flow paths in the inter-provincial water resource flow patterns in China was larger and more prominent in the network, while in 2017, high-level flow paths were concentrated on a few link paths and in the eastern and western regions, but the breadth of associations did not weaken significantly. ③ The hot spots of the outflow water footprints of China' s provinces gradually shifted from the water-rich areas to the water-scarce areas, while the hot spots of the inflow water footprints were concentrated in the rich-water areas. ④ The LISA time path showed that the local spatial structure of the inflow and outflow water footprints in China' s provinces was relatively stable, and the effect of spatial and temporal dependence was small, showing a trend of coordinated changes. The spatial cohesion of the outflow water footprints was higher than that of the inflow water footprints, but the degree of transfer between the two was relatively large. [ABSTRACT FROM AUTHOR]

Because of the continuous deterioration of water environment, it is ensured that the basic water demand of ecological environment is the key task of water resources utilization and control in China. In view of the uneven distribution of domestic water resources "more in the South and less in the north, more in the East and less in the west," it is very necessary to optimize the allocation of water resources. This paper aims to optimize the allocation of water resources through simulated annealing algorithm (SAA), hoping to optimize the allocation of water resources through diversion, water intake, and storage measures such as pipelines. Based on this, this paper proposes an improved SAA pipeline construction algorithm. Aiming at the distribution of water sources in the Yangtze River Basin, the algorithm is used to optimize the objective function path to solve the unbalanced problem of rich and lack of regional water resources. And after optimizing the annealing simulation algorithm, the simulation optimization ability is significantly improved. Experiments show that the improved SAA can improve the optimal configuration by more than 50% and up to 96%, indicating that the improved algorithm has a more stable optimization planning function for the optimization of objectives and can often get a more perfect route. [ABSTRACT FROM AUTHOR]

Whether the implementation of the water resources tax policy can stimulate the water-saving behavior of social water users is one of the important criteria for evaluating the implementation effect of the tax reform policy. Taking Hebei Province, the first tax reform pilot in China, as an example. A dynamic stochastic general equilibrium model (DSGE) with embedded water resources tax is constructed to simulate the persistent impact of water resources tax on water-saving objectives. The research shows that: (1) Water resources tax can effectively achieve the goal of water-saving and improve the utilization efficiency of water resources. (2) Levying water resources tax helps to improve the water-saving awareness of enterprises and residents. It can also encourage enterprises to optimize production structures. (3) Rational and efficient use of special water resources protection funds is the basis for ensuring the effective implementation of water resources tax. It can also improve the recycling capacity of water resources. The results show that the government should speed up formulating a reasonable water resources tax rate and accelerate the construction of water resources tax protection measures. To ensure the relatively steady state of water resources utilization and protection, and achieve the dual goals of sustainable economic development and sustainable use of water resources. The research results of this paper reveal the internal logic of the comprehensive impact of water resources tax on the economy and society and provide an important basis for the national promotion of tax reform policy. [ABSTRACT FROM AUTHOR]

Groundwater is a primary freshwater resource for human consumption and an essential source for industry and agriculture. Therefore, understanding its spatial and temporal trends and drivers is crucial for governments to take appropriate measures to manage water resources. This paper uses Gravity Recovery and Climate Experiment (GRACE) satellite data and the Global Land Data Assimilation System (GLDAS) to derive groundwater storage anomalies (GWSAs) and to analyze the spatial and temporal trends of GWSA in different regions of China (Xinjiang, Tibet, Inner Mongolia, North China Plain, South China, and Northeast China). It used groundwater-level observation data to verify the accuracy of GWSA estimates and analyzed the drivers of regional GWSA changes. The results showed that: (1) GWSA in South China increased at a rate of 4.79 mm/a from 2003 to 2016, and GWSA in other regions in China showed a decreasing trend. Among them, the decline rates of GWSA in Xinjiang, Tibet, Inner Mongolia, North China Plain, and Northeast China were −6.24 mm/a, −3.33 mm/a, −3.17 mm/a, −7.35 mm/a, and −0.75 mm/a, respectively. (2) The accuracy of the annual-scale GWSA estimates was improved after deducting gravity losses due to raw coal quality, and the correlation coefficient between GWSA and groundwater levels monitored by observation wells increased. (3) In Xinjiang, the annual water consumed by raw coal mining, industrial, and agricultural activities had a greater impact on GWSA than rainfall and temperature, so these human activities might be the main drivers of the continued GWSA decline in Xinjiang. Water consumption by raw coal mining and industry might be the main drivers of the continued decline in GWSA in Inner Mongolia and the North China Plain. The increase in groundwater storage in South China was mainly due to the recharge of rainfall. [ABSTRACT FROM AUTHOR]

From the perspective of value-added trade, this paper divides the virtual water consumption and trade in different provinces of China into five major paths according to the input-output relationship. In 2012 and 2015, most provinces' water resources were implicitly used in the final products to meet the local demand. In addition, the volume of virtual water trade in the complex domestic value chain is greater than that in the traditional domestic trade value chain and the simple domestic trade value chain. In both years, judging from the sum of virtual water trade volumes in the three major value chains, there is virtual water net inflow in Beijing-Tianjin and the northern, eastern and southern coastal areas, and virtual water net outflow in the northeast, central and northwest areas. In the course of this research, the virtual water net outflow turned into net inflow in the southwestern area. [ABSTRACT FROM AUTHOR]

Urban underground comprehensive pipe galleries (referred to as UCPGs) often have large rectangular cross sections and are now widely used as underground tunnel spaces for accommodating various engineering pipelines used for power, signal communication, gas, oil, heating, water supply, and drainage channels in China. The force–displacement relation for a pipe–soil interaction is very important since it can be used to evaluate the pipe behavior under various conditions. Conventional theoretical analysis methods are usually proposed for circular cross-sectional pipes, while few methods have been presented for UCPGs with large rectangular cross sections. This paper studies the two-dimensional rectangular pipe–soil interaction problem. The limit resistances of underground rectangular pipe galleries (URPGs) in undrained clay under purely horizontal and vertical loads are first investigated through two-dimensional finite-element limit analysis (FELA). Subsequently, the failure envelope of the URPGs under relative pipe–soil movement along various directions is investigated. Parametric analyses are carried out to derive the empirical equations of the limit resistance and failure envelope of the URPGs. The proposed empirical equations are verified by comparing the theoretical predictions with the FELA results and other researchers' studies, and they provide a basis for constructing the p–y relation of the pipe–soil interaction. [ABSTRACT FROM AUTHOR]

[Display omitted] • A model for multi-objective optimization operation of multiple water sources under uncertainties was proposed. • Uncertainties in inflow and water demand forecasts can be considered simultaneously, and the correlation between uncertainties can be considered quantitatively. • The impact of inflow-water demand forecast uncertainties and their correlations on water resource operations are explored for water resources managers. Uncertainties in inflow and water demand forecasts bring risks to water resources management. Therefore, the research on multi-objective optimization operation of multiple water sources under uncertainties holds critical research significance and application value. This paper proposes a model for the multi-objective optimization operation of multiple water sources that can consider the inflow and water demand forecast dual uncertainties. In handling uncertainties, this paper adopts a scenario generation method based on joint distribution-Monte Carlo (JDMC), which allows for a quantitative consideration of the correlation between uncertainties. Moreover, the variable weight method and LINGO 20.0 are employed for solving multi-objective optimization issues to obtain stable Pareto frontiers. The proposed model is applied to the water receiving area inside Jiangsu Province of the South-to-North Water Transfer East Route Project (SNWTERP) in China. The main findings are as follows: 1) The impact of the inflow and water demand forecast uncertainties on the operation results is synergistic rather than antagonistic. Considering only a single uncertainty may result in water receiving area facing more severe water shortages or purchasing spot water at high prices. 2) There is a strong spatial correlation between uncertainties. If we ignore or only qualitatively consider the correlation between uncertainties, the impact of uncertainties on operation results will be underestimated or overestimated. 3) The Pareto frontiers are convex functions, indicating that decision-makers should choose a solution in the middle part. [ABSTRACT FROM AUTHOR]

Little is known in the international academic community about Chinese‐language research on water management. To remedy this deficit, this paper reviews current mainland Chinese understandings of the role of large‐scale water infrastructures as tools of water resources management. We reviewed 461 papers published in mainland Chinese journals by Chinese scholars. This review suggests that the dominant approach to water management reflects the confines of government priorities—large‐scale, concrete‐heavy, infrastructure‐based means of moving water around the country so as to meet demands and stimulate economic growth. Suppression of critical voices means that infrastructure is generally rendered apolitical: the critiques are about practical issues, such as technological, managerial, or administrative problems. There are exceptions to this characterization that adopt more critical frames; however, they reflect on water management elsewhere or in the past rather than on contemporary China. While these more critical papers are interesting and important contributions to our understanding of the politics of hydraulic infrastructures, the literature as a whole says little about the politics of infrastructure in China now. In effect, much of the literature in Chinese on water management in China simply acts as an arm of a machine—a network of corporations, universities, international institutions, and arms of the government, together tasked with identifying and framing what are water management issues, formulating standardized procedures for tackling those issues, and then constructing solutions to them. This article is categorized under:Engineering Water > Planning WaterHuman Water > Water Governance [ABSTRACT FROM AUTHOR]

Since the completion of first‐phase projects on the eastern and middle routes of the South‐to‐North Water Diversion (SNWD), the design and implementation of water pricing mechanism have become the key factors that affect the project operation. This paper launches the evaluation of implementation effect on the water price policy of the SNWD built projects in 2018 by coordinating the consumption of transfer water, allocation of receiving‐areas' water resources, collection of water fee for transfer water, as well as the implementation of local water price policies, which mainly exerted a comprehensive and interactive influence on the water price policy. Based on a series of data statistics and analysis, the usage of water transferred from the Yangtze River, improvement of regional water resources allocation, collection of water fee, and the implementation results of local water price policies were systematically analyzed. The main conclusions and corresponding suggestions were put forward to provide useful references on the formulation of water price policies for the design, optimization, and adjustment of the subsequent water pricing mechanism in the SNWD project. [ABSTRACT FROM AUTHOR]

Evaluating the water resources carrying capacity (WRCC) is the prerequisite and foundation for the planning and management of water resources. In this paper, according to risk theory, a framework for the risk assessment of WRCC was proposed based on the fragility of damage‐affected bodies and the damage posed by disaster‐inducing factors. Then, based on water quantity, water quality, water area, and water flow, a fragility index system was constructed from the water resources, economy, and society category. Additionally, the damage was analyzed in terms of climate change, urbanization, and industrialization. Finally, a model for the risk assessment of the WRCC was established by combining the fragility of the water resources carrying system with the compound damage posed by climate change, urbanization, and industrialization. The developed model was then applied to assess the risk of the WRCC in North China in 2017. The results indicate that the fragility of the WRCC was the highest in the Beijing–Tianjin–Hebei region, and the compound damage showed an increasing trend from the southeast to the northwest in North China. Meanwhile, the risk of the WRCC decreased from the southeast to the northwest, the highest risk was observed in Hebei Province, and the lowest risk was observed in Inner Mongolia. This research provides an important technical guideline for the sustainable utilization of water resources and the coordinated development of the economy and society. [ABSTRACT FROM AUTHOR]

To protect and restore this downstream ecosystem, the Tarim River Basin Administration Bureau (TBAB) initiated the Ecological Water Compensation (EWC) project from 2000 to 2018. Revealing the mechanism of vegetation-hydroecological response processes in the lower reaches of the Tarim River before and after EWC work is conducive to water resource planning, utilization and protection. In this paper, the spatiotemporal responses of vegetation and groundwater to EWC were examined at the points, lines, and area (PLA) scale by coupling remote sensing techniques and field station observation data collected between 2000 and 2017. The findings indicated that (1) In general, the regional fractional vegetation coverage (FVC) increased significantly, and the average FVC growth rate was 3.5%/year from 2000 to 2017 (R2 > 0.84, p < 0.01, 2-tailed). (2) The regional vegetation restoration process showed obvious fluctuations and stage characteristics, but the spatial scope of the significantly increased vegetation area was limited. Plants grew rapidly within 10 km of the river, while 10 km away from the water channel, no obvious change was observed. (3) Strong coupling relationships were identified among the FVC growth, EWC volume and groundwater depth variations (p < 0.05, 2-tailed). The response times of the regional vegetation and groundwater depth to EWC indicated one-year lags. The above results imply that the regional ecological environment was significantly improved over the study period, thus confirming that the EWC project made remarkable accomplishments. However, the effect of ecological restoration is not sufficiently stable at present. Vegetation restoration has mainly been centralized around the river channel and is greatly dependent on the annual EWC volume. In addition, the local conditions begin to degrade soon after an EWC project is terminated, and vice versa; when EWC commences, the FVC immediately begins to improve. Therefore, the current EWC achievements need to be further consolidated and strengthened in the future. [ABSTRACT FROM AUTHOR]

The aim of the present review is to report and discuss the relevant literature on environmental impact of sea water desalination in China. China, especially its coastal provinces, is facing a serious shortage of fresh water resources and a water pollution issue, restricting further development. To address the serious imbalance between water resource supply and demand, in addition to efficiently utilizing the regular water resources, China has strived to develop alternative water resources to combat the water crisis, among which seawater desalination plays an important role. This paper reviewed the current situation of the utilization of desalinated seawater in China, including the points outlined below. In order to reduce the detrimental effects of desalination technologies on the environment and to make them sustainable it is of fundamental importance to develop ―circular‖ approaches aimed at valorizing the concentrate streams requiring disposal, with the ultimate goal of zero liquid discharge. It was found that extensive research has been performed on Mg extraction (mainly as brucite) from seawater brines using different technologies; although a few demonstration-scale studies exists on Mg recovery processes both from seawater from industrial brines, most of the recovery technologies are still performed at laboratory scale. In the long term, it is of significant importance to develop desalination technologies to face the challenges of global water crisis. Desalination technologies in China are vital both in the field of freshwater extraction from the sea and the improvement of water environment and ecology. Specifically, emphasis should be put on the following aspects as follows: (1) Technology innovation: Further improve the performance of large-scale SWRO plants. Efforts include the enlargement of single unit capacity, decrease of energy consumption, improvement of system integration, operational stability and reliability, and desalination cost. Further endeavors should be made towards pretreatment and system instrumentation, highperformance RO membranes and elements, high-pressure pumps and energy recovery devices, etc. (2) Utilization of chemical resources from seawater: The extraction and reuse of chemical resources from seawater desalination is an attractive topic from a scientific point of view. Better technologies need to be explored to recover chemicals and reduce possible cost. Moreover, the extraction of strategic elements such as lithium and uranium is more challenging and needs better technologies. (3) Green pretreatment methods ; Attention should be paid to the development of green pretreatments involving green antiscaling agents and agent-free biological methods. It is advisable to investigate electrocoagulation and dissolved air flotation techniques.(4)Emerging desalination technologies: Apart from the traditional SWRO desalination technologies, emerging technologies including MD, CDI, and ED desalination processes require more research efforts, from the exploitation of novel membrane materials to the fabrication of core components and equipment. In addition, hybrid systems coupling the traditional technologies and the emerging technologies should be further promoted to make the most of the less-popular technologies. Overall, with the ongoing research and development of desalination, China is believed to play a more and more important role in the international desalination market with remarkable openness and inclusiveness, providing state-of-the-art desalination technologies, facilities and services, benefitting the water-stressed countries and regions in the world. [ABSTRACT FROM AUTHOR]

The risk of water resources has become a serious crisis threatening the human survival and social development. Based on the establishment of a comprehensive risk evaluation system from perspective of water quantity and water quality, this paper proposes a group TODIM (an acronym in Portuguese for Interactive and Multi-criteria Decision Making) with multi-granularity proportional hesitant fuzzy linguistic term sets (PHFLTSs) based on a novel comparison method to evaluate water resources risk. In the method, a novel supplementary of extension function and hesitation value function of comparing and measuring the PHFLTSs is firstly proposed. Furthermore, incomplete weight information method is introduced to establish optimization model to compute the final indicator weights, which are extended to TODIM method to evaluate water resources risk of Hubei Province of China. Finally, the availability and reliability of the method are confirmed by further analysis, and specific management suggestions are put forward to reduce the associated risk. [ABSTRACT FROM AUTHOR]

Climate change and human development have significantly altered the processes of natural water cycling, aggravating the challenge of worldwide water governance. China has initiated a new paradigm of water governance. However, the gap between concept and reality widened due to a lack of appropriate data and methodology. Current water management focuses on limiting the water withdrawals and improving the water use efficiency, and is not yet able to ensure the implementation of the new water governance paradigm. After a thorough study of the advanced development and achievement of water governance policies both at home and abroad, the conclusion has been reached that the total water consumption should be introduced as an additional management indicator to implement a dual control of water withdrawal and consumption. The paper proposes to: (1)Establish water consumption monitoring infrastructure with evapotranspiration remote sensing monitoring as its core component. (2) Implement the rigid water resources constraint by determining available water consumption targets of human activities in the basin, considering water requirements of environmental flow and ecosystem restoration, and establish a cascading system assigning targets to the sectors and/or stakeholders. (3) Implement the water consumption reduction schemes by limiting agricultural planting areas and optimizing ecosystem restoration with indigenous species. It is expected that the proposed approaches will effectively ensure the implementation of China′s new water resources governance paradigm with innovative data, methods, and measures. [ABSTRACT FROM AUTHOR]

Under the background of "double carbon", ecological water has become one of the significant resources to ensure the healthy and sustainable development of the regional ecological environment. And the ecological water consumption prediction is a prerequisite for optimizing water supply structures. Considering the impact of CO 2 emissions on ecological water consumption, the FGM(1,1) model was firstly used to predict CO 2 emissions considered as an impact factor in this paper. Then, an adjacent accumulative grey multivariate convolution model (AGMC(1,N)) was combined with the Average Weakening Buffer Operator (AWBO) to predict the annual ecological water consumption of 30 provinces (municipalities and autonomous regions) in China. The results show that the AGMC(1,N) model combined with the AWBO has better prediction effect. In addition, in the next decade, only six provinces in the northern region will have a decreasing trend in ecological water consumption. However, the other provinces are showing an upward trend. The ecological water consumption trends deviate from the CO 2 emission trends in 12 provinces. The research results are beneficial for the formulation of the ecological water consumption policies and the achievement of the dual carbon goals. [ABSTRACT FROM AUTHOR]

• Significantly changes of LAI and GPP mostly occurred in eastern and southern China. • Divergence between LAI and GPP were found in regions with dense vegetation coverage. • The importance of VPD, SM, and PT to vegetation indices increased as latitude decreases. Climate change notably boosts terrestrial hydraulic redistribution pattern, which could directly affect the spatiotemporal evolution characteristics of vegetation productivity. However, the spatiotemporal evolution pattern of long-term hydrometeorological controls of vegetation productivity is still not fully understood. This paper comprehensively explored the impacts of hydrometeorological controls on leaf area index (LAI) and gross primary productivity (GPP) in China during 1982–2015 using both satellite observations and reanalysis. Vapor pressure deficit (VPD), evapotranspiration (ET), precipitation (PT), and soil moisture (SM) were used as representative indicators during investigation. The dynamics of LAI and GPP displayed increasing trends on the whole. And significantly changes mostly occurred in eastern and southern China, accompanied by moderate to dense vegetation coverage. An accelerated increasing trend for LAI could be observed since September 2003 (+0.175 per decade), while the growth rate of GPP (+16.76 g C/m2 per decade) basically maintained stable. In terms of hydrometeorological controls, VPD and ET showed consistently increasing trend and SM presented falling trend in the context of warming climate. Through analysis of feature importance index established by Random Forest, the importance of VPD, SM, and PT obviously increased as latitude decreases, which implied the high sensitivity of vegetation in semi-humid\humid regions to water availability. Additionally, divergence between LAI and GPP can be found in southern Tibet Plateau region and coastal regions, which provides compelling evidence that in the case of high LAI, increasing LAI could weaken the improvement effect on GPP. Findings of this study is expected to promote the understanding of long-term vegetation responses to hydrometeorological variations. [ABSTRACT FROM AUTHOR]

• This paper constructed a framework for green water assessment in the Loess Plateau gully region using MIKE SHE model. • A new concept and extraction method for green water components was defined based on existing research. • A new concept of the potential of green water was defined in relation to the dried soil layers' classification indicators. • We assessed the dependence on green water components and potential for environmental changes. Exponentially increasing water demand and increasingly uncertain hydrological conditions due to climate change (CC) and land use/cover change (LUCC) undoubtedly pose significant challenges to the sustainability of water systems in arid and semi-arid regions worldwide, and even more so in the rain-fed agricultural area of the Loess Plateau (LP) in China, where green water supports all ecological landscapes and most agriculture. Therefore, an accurate assessment of green water resources is crucial for regional development. This paper constructed a comprehensive framework for assessing green water resources based on the MIKE SHE model, defined a new concept of green water components (GWCs) that can be extracted based on existing studies, proposes the potential of green water (GW P), and present a research methodology. To validate this research framework, we applied it to a typical basin in the LP gully area of the Nanxiaohegou (NXHG) basin. The model was calibrated using runoff data from basin outlet stations to extract four GWCs: high-efficiency green water (GW H), low-efficiency green water (GW L), unused green water (GW U), ineffective green water (GW I). We then assessed the GW P of the basin and analyzed its trends, consistency, and dependence on changing environments. The assessment framework is simple and easy to use, providing valuable information for regional revegetation and basin water management, and is highly recommended for replication in other regions. [ABSTRACT FROM AUTHOR]

Based on the SBM model including unexpected output, this paper studies the water resource utilization efficiency of 30 provinces in China from 2003 to 2019. The study found that China's water resource utilization efficiency showed obvious provincial differences. The water resource utilization efficiency of most eastern coastal provinces was relatively high, and that of most central and western inland provinces was not high. There are also significant differences among the three regions of the East, the middle, and the West. The utilization efficiency of water resources in the East is the highest, followed by the middle, and the West is the lowest. The redundancy of input factors, such as labor, capital, and water consumption, is the main reason for the low efficiency of water resource utilization, and the redundancy of wastewater discharge also affects the efficiency of water resource utilization. The clustering results show that the utilization efficiency of water resources in most provinces of China is located in medium efficiency area and low efficiency area, and the efficiency needs to be improved. There are relatively few provinces in high-efficiency areas, highlighting that China's water resource utilization still faces severe challenges. [ABSTRACT FROM AUTHOR]

Water system management is a worldwide challenge, especially in arid and semi-arid regions. Ecological water conveyance projects aim to raise the groundwater table, thereby saving natural vegetation and curbing ecological deterioration. Since 2000, these projects have been implemented in the arid zone of northwest China, with generally successful outcomes. Taking a portion of the lower reaches of the Tarim River as the study area, this paper analyzes in detail the ecohydrological effects which have occurred since the launching of artificial water conveyance 20 years ago. The results show that the groundwater table in the upper, middle and lower segments of the Tarim River's lower reaches has been raised on average 4.06, 4.83 and 5.13 m, respectively, while the area of surface water bodies connected to those sections has expanded from 49.00 km2 to 498.54 km2. At the same time, Taitema Lake, which is the terminal lake of the Tarim River, has been revived and now boasts a water area of 455.27 km2. Other findings indicate that the surface ecological response is extremely sensitive and that the area of natural vegetation has expanded to 1423 km2. Furthermore, the vegetation coverage, vegetation index (NDVI), and Net Primary Productivity (NPP) have increased by 132 km2, 0.07 and 7.6 g C m−2, respectively, and the Simpson dominance, McIntosh evenness, and Margalef richness indices have risen by 0.33, 0.35 and 0.49, respectively, in the monitored sample sites. As well, the carbon sink area has expanded from 1.54% to 7.8%. Given the increasing intensity of the occurrence of extreme hydrological events and successive dry years, similar ecological water conveyance projects should be considered elsewhere in China and in other parts of the world. The water conveyance scheme has generally proven successful and should be optimized to enhance the benefits of ecological water conveyance under water resource constraints. [ABSTRACT FROM AUTHOR]

Managing transboundary river basins proves a challenge for China when encountering disagreements with its neighbors that experience different political and social conditions. This paper analyzes what happens when China characterizes water as a security issue, examining China's fluid securitization practices, where changes can be identified indicating that the Chinese government values the various water security concerns differently. Two cases are adopted for comparison. In the case of China sharing the Mekong River, the Chinese government has shown a willingness to incorporate more issues found both inside and outside of the water sector. In contrast, in the case of the sharing of the Ganges-Brahmaputra-Meghna, China's security agenda has been limited to the consideration of water availability and has led to military security concerns. The findings indicate that China's water security agenda is not only driven by a concern for water management over specific rivers, but also judgments that incorporate strategic military consideration with regard to countries that they are involved with. The case of China thus suggests that water security is a complex domain that demonstrates competing values and concerns in (de)politicizing water. Therefore, water-related security issues cannot be understood solely from an environmental policy perspective. [ABSTRACT FROM AUTHOR]

This paper establishes a quantitative model based on the system dynamics (SD) theory to reflect the 'socioeconomic–water–environment' coupling system and proposes three future development scenarios. Hubei province, China, is selected to verify this model. The simulation results from 2020 to 2030 demonstrate that the pressures of water supply and demand and pollution under the sustainable development scenario are less than those under two other scenarios. It means that adjustment of the industrial structure has a relatively weaker effect on alleviating the pressure of water supply and demand. Saving water and controlling pollution should be the emphasis of current efforts. [ABSTRACT FROM AUTHOR]

Using China's provincial panel data during 2006-2019, this paper attempts to research the impacts of environmental regulation on green water efficiency. A Slacks-Based Measure-Data Envelopment Analysis (SBM-DEA) model with undesirable outputs is used to evaluate green water efficiency for thirty provinces in China. The result indicates a relatively low green water efficiency and significant difference between provinces in China. We have three main findings: (1) The efficiency of green water resources in eastern China is on the rise, and there is a necessity to make further optimization. (2) Environmental regulation has a positive effect on the national green water efficiency. Because of regional differences, environmental regulation has a significant positive effect on the green water efficiency of both the east and the west, but its impact on the western green water efficiency has not passed the significance test. Still, the negative elasticity coefficient indicates that environmental regulation is not conducive to improving the efficiency of green water resources in the west. (3) As for control variables, technological progress, education input, urbanization rate, and the level of opening up facilitate more rapid the growth of green water efficiency in the east. The roles of the level of opening up, education input, and urbanization rate in improving central green water efficiency are extremely obvious. There is a negative correlation between economic development and green water efficiency in western China. Except for the abundance of water resources and foreign capital utilization of the west, the remainder of control variables shows a positive effect. [ABSTRACT FROM AUTHOR]

Based on the precipitation records of 2474 meteorological stations, this study investigated precipitation characteristics and trends in China from 1961 to 2010, including spatiotemporal distribution and changes in average annual precipitation amount, number of days when daily precipitation > = 1, 5, 10, 25, 50 mm, and extreme precipitation indices. The results showed that: (1) in terms of annual average precipitation amount, both dry to wet, wet to wetter, and shifting between wet and dry showed decadal and climatical fluctuations in annual precipitation totals in space and time, with a clear shift in space from the 0 to 200 mm and above 400 mm precipitation levels to the 200 to 400 mm precipitation level. (2) In terms of graded precipitation days, three kinds of trend changes were observed: (a) enhancement, manifested as an increase in precipitation events, mainly in the northwest and northeast of China; (b) reduction, manifested as a decrease in precipitation events, mainly in the central parts of China; and (c) polarization, which is manifested as a decrease in gentle and light precipitation events but an increase in dry days, heavy, and rainstorm precipitation events, primarily along coastal area in southeast China. (3) In terms of extreme precipitation events, precipitation persistence showed a decreasing trend, but an increasing trend in precipitation intensity and magnitude in most regions of China. This paper also presents the relationship between certain atmospheric circulation indices and the seasonal precipitation of summer and winter. The distribution characteristics and changes in minor precipitation events were highlighted, including gentle and light rain events. Relevant findings can provide scientific guidance for water resource management and conservation. [ABSTRACT FROM AUTHOR]

Arid area is very sensitive to global warming and are extremely vulnerable to climate change. Moreover, the water resources system in the arid area is fragile and will undergo tremendous changes with climate change. Therefore, the interaction of climate and hydrology in arid area has an important impact on the formation of regional microclimate and hydrological changes. Daihai Lake is a typical closed inland lake in arid area of China, and a key area for ecological protection in North China. In this paper, WRF-Hydro model is used to simulate the climate hydrological coupling situation of Daihai Basin from 1980 to 2020, and the coupling results are verified and calibrated by meteorological statistics, runoff calculation and remote sensing analysis. Based on the synopsis of climate and hydrology in the past 40 years, the causes and future trends of the hydrological elements in Daihai Basin are analyzed. Through the analysis, it is found that the interannual variation of precipitation in Daihai Basin is sharp, with 401.75 mm as the average from 1980 to 1994; and drastic fluctuations from 1995 to 2011, with a difference of nearly 400 mm between the interannual maximum and minimum; From 2012 to 2020, the fluctuation is small. Although the interannual variation of evaporation fluctuated, it showed an upward trend with a slope of 8.855 mm/year. The annual average temperature showed an obvious upward trend with a slope of 0.040 °C/year. From 1980 to 2020, the inflow of Daihai Lake shows a downward trend; Since 2013, the runoff into the lake has tended to be flat. Climate change and human activities are the decisive factors leading to the change of water quantity in Daihai, among which human activities play a greater role. Cultivated land irrigation and industrial water use are highly correlated with the lake discharge, and these two factors have a great influence on the lake discharge. If the current agricultural and industrial water consumption does not increase, Daihai still has a lifespan of nearly 120 years. If human activities do not change and any protective measures are not taken in time, under the background of global climate change, the flow of the Daihai Lake into the lake will be reduced to zero in 2025, and the Daihai Lake will completely dry up in 2031–2033. The study of climate hydrological coupling of long time series in Daihai Basin can not only make up for the lack of runoff data, but also provide the basis for water resources management, disaster prevention and mitigation. [ABSTRACT FROM AUTHOR]

Arid area is very sensitive to global warming and are extremely vulnerable to climate change. Moreover, the water resources system in the arid area is fragile and will undergo tremendous changes with climate change. Therefore, the interaction of climate and hydrology in arid area has an important impact on the formation of regional microclimate and hydrological changes. Daihai Lake is a typical closed inland lake in arid area of China, and a key area for ecological protection in North China. In this paper, WRF-Hydro model is used to simulate the climate hydrological coupling situation of Daihai Basin from 1980 to 2020, and the coupling results are verified and calibrated by meteorological statistics, runoff calculation and remote sensing analysis. Based on the synopsis of climate and hydrology in the past 40 years, the causes and future trends of the hydrological elements in Daihai Basin are analyzed. Through the analysis, it is found that the interannual variation of precipitation in Daihai Basin is sharp, with 401.75 mm as the average from 1980 to 1994; and drastic fluctuations from 1995 to 2011, with a difference of nearly 400 mm between the interannual maximum and minimum; From 2012 to 2020, the fluctuation is small. Although the interannual variation of evaporation fluctuated, it showed an upward trend with a slope of 8.855 mm/year. The annual average temperature showed an obvious upward trend with a slope of 0.040 °C/year. From 1980 to 2020, the inflow of Daihai Lake shows a downward trend; Since 2013, the runoff into the lake has tended to be flat. Climate change and human activities are the decisive factors leading to the change of water quantity in Daihai, among which human activities play a greater role. Cultivated land irrigation and industrial water use are highly correlated with the lake discharge, and these two factors have a great influence on the lake discharge. If the current agricultural and industrial water consumption does not increase, Daihai still has a lifespan of nearly 120 years. If human activities do not change and any protective measures are not taken in time, under the background of global climate change, the flow of the Daihai Lake into the lake will be reduced to zero in 2025, and the Daihai Lake will completely dry up in 2031–2033. The study of climate hydrological coupling of long time series in Daihai Basin can not only make up for the lack of runoff data, but also provide the basis for water resources management, disaster prevention and mitigation. [ABSTRACT FROM AUTHOR]

Drought is a major natural hazard that can have devastating impacts on regional agriculture, water supply, ecological environment and social economy. Extreme events, including droughts, are expected to be severer and more frequent because of climate warming. This paper presents an analysis of observed changes and future projections of meteorological drought in the Daqing River Basin (DRB), North China, based on the modified Standardized Precipitation Index (SPImod). Observed changes of meteorological drought are analyzed based on the precipitation series of 26 meteorological stations from 1971 to 2011, and future projections are made under two representative concentration pathways (RCPs 4.5 and 8.5) from 2021 to 2050. The result shows a change from wet to dry detected in most areas of the DRB in summer, winter and annual series. The drought risk is higher under the condition of "OR" and "AND" return period during the observation period, and the high-risk regions cover a large area. The drought risk from 2021 to 2050 will increase across the basin under RCP 4.5 and RCP 8.5, compared with which in the base period from 1971 to 2000. Most regions will be at a higher drought risk under the condition of "OR" return period, and the area with high-risk under RCP 4.5 is slightly larger than that under RCP 8.5. Under the condition of "AND" return period, the high-risk regions will cover the area from the northwest to the northeast, while the area of high-risk regions under RCP 8.5 will be larger than that under RCP 4.5. The result of this paper will be helpful for performing an efficient water resource management in the DRB under the impacts of global warming and climate change. [ABSTRACT FROM AUTHOR]

China suffers from frequent large-scale earthquakes, posing a significant challenge to the development and integrity of its rural water supply system (RWSS). The earthquake resilience of water supply systems is understood to be a function of multifaceted factors, which are time- and space-dependent. Measuring the seismic-resilience of RWSS in China remains a challenge. This paper proposes a multi-stage comprehensive evaluation framework, focusing on the relationship between multi-dimensional factors and the seismic- resilience of RWSS in rural areas, across three stages: before, during and after earthquake events. This study comprises four steps: (1) Development of a multi-stage evaluation conceptual framework; (2) identification of seismic-resilience factors; (3) verification of the relationships between factors and stages; and (4) formation of the final evaluation framework. The relationship between multi-dimensional factors is confirmed by a method of triangulation through the quantitative analysis of PLS-SEM combined with the qualitative literature analysis, highlighting the causal approach of the resilience of RWSSs, so as to better understand the resilience state of each stage of disaster. Understanding these factors and their influence on the seismic capacity of RWSS will enable local authorities to recognize the existing advantages and disadvantages of these factors, so as to carry out better resilience practice in all stages of disasters. [ABSTRACT FROM AUTHOR]

Deep coal seam mining often leads to water resource loss due to bedrock water entering the workings of the mine and is discharged adjacent to the mining area. Using the geological conditions of the Maiduoshan coal mine, this paper applied a physical simulation experiment. The specified rock above the coal seam was hydraulically fractured in advance to form a postmining grouted fracture network, followed by grouting to construct a flexible isolation layer that blocked the infiltration of groundwater from the aquifer into the water-conducting fracture zone. Stress sensors, flow sensors and strata displacement monitoring technology were deployed inside the experimental material to study the spatial distribution characteristics and evolution law of the water-conducting fracture zone in the overlying rocks. Analysis of the water-conducting fracture zone development law, stress variation, overburden evolution characteristics, fracturing and grouting sequence of the flexible isolation layer and the effect of postmining grouting on the water barrier was conducted. These experiments verified the feasibility of fracture and grouting of the flexible isolation layer. These research results will provide practical guidance for the transition from the current safe and efficient mining methods to safe and green mining methods of deep coal mining in the western mining areas of China. [ABSTRACT FROM AUTHOR]

Water security is an integrated concept of multiple dimensions, including water resource utilization, water eco-environmental protection, water disaster prevention among others. In this paper, an evaluation indicator system of water security are constructed, focusing on five dimensions: water quantity, water quality, sustainability, affordability, and flood security. It is based on a summary and discussion of the definition, connotation, and evaluation of water security dimensions. We provide increased understanding of applicability and usefulness of water security evaluation systems, thereby avoiding content duplication or overlaps between different dimensions and promoting the accuracy of problem diagnosis. In doing so, we used a multi-expert decision-making method to quantify indicators weight and to standardize data. Compared with evaluating the water quantity security using indicators of water resources endowment alone, this evaluation system implies concepts of water demand and sustainable security that included in resource security, which is capable of analyzing actual reasons for water shortage. Affordability, which is seldom considered in previous studies, is supplemented to ensure system integrity of water security assessment. Finally, a case study of water security evaluation of China is carried out with cluster analysis. The main water security problems in each region of China were diagnosed well, which are in line with the current situation of China. This test indicates that the evaluation system is both reliable and practically applicable. [ABSTRACT FROM AUTHOR]

Water option trading aims at solving the problem of uneven spatial and temporal distribution of water resources. With the change of global climate, rainfall has become an important factor leading to the uneven spatial and temporal distribution of water resources. In this paper, Markov chain is used to divide and forecast the rainfall scenarios. On the basis of rainfall forecast, the related costs of water option trading are determined. The forecast results of rainfall index are integrated into the determination of the ultimate overprice of water options. The improved Black- Scholes option pricing model is used to determine the rights of water options trading based on the forecast results of rainfall. Finally, the rationality of the calculation results is verified by using the extended linear expenditure model, which proves the rationality of the transaction price determined by the model. Taking Guangdong province as an example, this paper verifies the necessity of incorporating rainfall index into water option trading and the rationality of the related costs of water option trading determined by the model, and proves the superiority of fluctuating water price over stepped water price. Water option trading considering rainfall fully reflects the relationship between supply and demand in water market, and improves the scientificity of water option trading pricing in China. [ABSTRACT FROM AUTHOR]

Due to the shortage of water resources, serious water pollution, improper use of water and the occupation of agricultural water rights by other industries, China's agriculture will face the risk of water shortage in the future. Due to the amount of water resources in North China is relatively small compared with that in South China, coupled with extensive operating methods and the low level of agricultural irrigation technology, water resources are wasted seriously, the problem of agricultural water shortage in North China is more serious. Optimal allocation of water resources is one of the main measures to alleviate the shortage of agricultural water resources, and is an important means to achieve sustainable use of water resources. Accurate prediction of regional agricultural water consumption is the key to optimal allocation of water resources. Grey model is a method to study “poor information”, “small sample” and uncertainty problems, which is widely used in economics, finance and other fields. The amount of historical data of annual agricultural water consumption is not enough, which is affected by many factors, and has concussion. Therefore, it is suitable to use grey model to predict agricultural water consumption. The oscillation characteristics of agricultural water consumption data series have a certain impact on the prediction accuracy of the model. To resolve these problems, an improved fractional grey prediction model is proposed in this paper. Based on the monotonically decreasing non-negative series which transformed from the oscillation series of the agricultural water consumption, a multi-objective optimization model was constructed according to the two objective functions of “maximum (or minimum) order” and “the best fit of historical data”, which was solved by the improved non-dominated sorting genetic algorithm II (NSGA-II) method. Agricultural water consumption in the test set for the research areas of Tongliao city (42°15′N～45°59′N, 119°14′E～123°43′E), Ordos city (37°35′24″N～40°51′40″N, 106°42′40″E～111°27′20″E) of Inner Mongolia autonomous region and Baoji city(33°35′N-35°06′N,106°18′E-108°03′E) of Shaanxi province was predicted by the grey model (GM(1,1)) model of fractional order reverse accumulation, the order of which was optimized according to the results of the test set fitting. The average error of the prediction was 2.23%,1.77% and 0.31%, respectively. In order to test the performance of the model, the model proposed in this paper was compared with the traditional GM (1,1) model, traditional autoregressive model and the combined model based on the wavelet analysis theory respectively. Among them, the average prediction error of GM(1,1) model for the three research areas is 5.55%, failed detection, and 1.28%. The average prediction error of autoregressive model for the three research areas is 3.34%, 4.17% and 6.49%. The average prediction error of agricultural water consumption in Ordos City of Inner Mongolia Autonomous Region based on the combination model of wavelet analysis theory is 2.87%. The results show that compared with GM(1,1) model, the prediction effect of the model in this paper is better, which depends on the objective function of “the best fitting of historical data” and the objective function of “the largest (or the smallest) order” to reduce the learning degree of the model for noise, because the model in this paper transforms the oscillating data and reduces the uncertainty of the data, so compared with the autoregressive model without data processing, the model in this paper is less affected by data volatility. In this paper, the idea of fractional order “in between” is used to improve the traditional gray model with positive integer as order, which can effectively improve the accuracy of the model. At the same time, the method of reverse accumulation is used to increase the use of new data. On the whole, for the prediction of agricultural water consumption in all research areas, the model in this paper has the minimum error, strong generalization ability and certain practicability, which can provide a basis for the prediction of regional agricultural water consumption and the allocation of agricultural water resources in northern China. [ABSTRACT FROM AUTHOR]

This paper explores water commons and its governance in China. Neither oriental despotism nor fragmented hydraulic state accurately describes water governance in China. Instead, a combined approach of Grand Union governance logic and polycentric policy-making analysis is proposed. The paper argues that the concept of the commons in China is dual-dimensional, with a vertical dimension of public authority and a horizontal dimension of sharing-in-common; that power structures have often been flexible, adaptive, polycentric and highly experimental; and that, correctly applied, this approach also strives to serve the common good, ensuring positive impacts for shared prosperity, while mitigating negative impacts. [ABSTRACT FROM AUTHOR]

This study investigates the water supply risk of Panjiakou reservoir in the Luanhe River basin of China during 1956–2016 under environmental change. Since the monthly runoff series during 1956–2016 is a time series with change points, it is necessary to find a new stochastic streamflow series generation approach to preserve the statistical characteristics of the original series and to refine the reliability of water supply risk analysis. This paper improves a known stochastic streamflow simulation method of previous research to better reflect the characteristics of series with change points. And this paper simulates the monthly runoff series with change point of Panjiakou reservoir during 1956–2016 by three different methods, including Thomas–Fiering model, copula function stochastic simulation method, and copula function stochastic simulation method with the mixed distribution model. Among the three methods, the copula function stochastic simulation method with the mixed distribution model which is improved on the basis of copula function stochastic simulation method in this study performs best in simulating the observed monthly runoff series during 1956–2016, and the water supply risk indices including reliability (time-based and volume-based), resilience, vulnerability, drought risk index (DRI), and sustainability index (SUI) are evaluated for Panjiakou reservoir and analyzed by using the stochastic simulation results. By comparing with the previous studies, all indicators are between the corresponding results of 1956–1979 and 1980–2016 with stationary inflows; it can be seen that change point seriously affects the water supply risk of Panjiakou reservoir. These results make it easy to formulate water supply strategies and schemes in changing environment for water resources managers. [ABSTRACT FROM AUTHOR]