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Urbanization has a great impact on urban evapotranspiration. Water evaporation inside buildings is an important part of urban water vapor resources and a crucial core of urban hydrological processes. The systematic studies on building water evaporation (BWE) are mostly the method of experimental monitoring. This study proposed a new method to simulate and estimate water evaporation flux inside buildings in urban areas. Based on the nighttime light data and urban per capita gross domestic product (GDP), a new modeling system was built to simulate the total BWE. Building area was calculated using the nighttime light data. And the BWE coefficient Df was estimated according to the important indicator of economic development per capita GDP value. Then the water evaporation inside urban buildings and the spatial distribution of water evaporation inside buildings in typical cities could be obtained. The results showed that the total amount of water evaporation inside buildings in China's urban areas was 24.5 billion m3. Among the 31 provincial capitals in China, Shanghai had the largest BWE of 1.08 billion m3. The minimum water evaporation of buildings in Lhasa was 20.0 million m3. Studies of BWE can assess urban water budgets, support on‐demand allocation of water resources, and provide a fundamental understanding of the relationship between water resources and energy heat island effects in urban areas. [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]

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]

This study investigates shared benefits through the cooperation between North Korea and China over transboundary water management in the Yalu River Basin. Primary attention has been placed on joint hydropower development since the 1950s, which has brought in developmental benefits for North Korea and security benefits for China. Data on the study have been collected from relevant papers, government publications, and media reports of China and South Korea. The information on North Korea, particularly about hydropower dams, is only accessible through secondary sources collected from South Korean government thinktanks due to the lack of publicly available data. The case study method is deployed for exploring specific issues and context and addressing problems. The significance of the study lies in the fact that this study is one of the first studies to examine transboundary river cooperation for development and security benefits between the countries. An array of bilateral agreements over the river basin has culminated in co‐building and jointly operating the four dams along the river. The construction of two additional dams, which is nearing completion, symbolizes shared benefits for both countries, hydroelectricity for North Korea, and regional security for China. Research Impact Statement: The study provides an in‐depth and unique analysis of joint hydropower development between North Korea and China in the Yalu River Basin. [ABSTRACT FROM AUTHOR]

As a fundamental natural resource and a strategic economic resource, water resources play a key supporting role in the process of social and economic development. In this paper, risk factors influencing the water resources carrying capacity (WRCC) were investigated based on risk theory and resources carrying capacity theory, and a method for the risk assessment of the WRCC was proposed. The vulnerability of WRCC system was evaluated by using the Fuzzy Comprehensive Evaluation method, the hazard of WRCC system was calculated by using the comprehensive hazard index, and then the risk of WRCC was obtained by combining the vulnerability with the hazard. The risk of WRCC in China due to climate change, urbanization, and industrialization was thoroughly investigated. The results demonstrated that the risk of WRCC was higher in Northern China than in Southern China and was higher in developed areas than in developing areas. The risk was observed to be highest in the Beijing–Tianjin–Hebei region. Meanwhile, the results also suggested that the risk of WRCC can be reduced in two ways: (1) Reducing the pressure on the water resources carrying system caused by economic and social activities; and (2) increasing the water resources supply in certain areas. The risk assessment of the WRCC presented here provides a valuable reference for the management and sustainable utilization of water resources in China. Research Impact Statement: The risk assessment of WRCC provides a valuable reference for the management and sustainable utilization of water resources in China. [ABSTRACT FROM AUTHOR]

Global warming and the rapid development of urbanization increase the likelihood of the occurrence of urban inundation, causing serious economic losses and threats to people's lives. Low impact development (LID) practices have attracted increasing attention as an effective approach which can mitigate urban inundation to some extent. Investigating the impact of LID practices on urban inundation is of significant importance to the prevention and control of urban flooding. This study constructed a coupling model with the combination of Storm Water Management Model and a 2D hydrodynamic model to provide a comprehensive simulation of urban inundation. The inundation situations are simulated with various scenarios by considering the implementation of LID practices under various rainfall return periods in Wuhan, China. We found that the LID practices can be more effective for urban inundation mitigation under rainfall events with smaller magnitude, and its ability in reducing the flood risk is weakened for extreme rainfall events. The results showed that LID practices can reduce the inundation area by 22.52%–38.9%. Especially for the inundation area with water depth larger than 0.4 m, the LID practices can reduce the inundation area by 71.52%–88.73% under different scenarios. Besides, the LID practices have a certain impact on the inundation area affecting traffic with a reduced rate of 37.2%–90.06%. This study can provide scientific support and a potential guiding significance for the future implementation of LID practices in cities under similar construction conditions. [ABSTRACT FROM AUTHOR]

Regulated rivers worldwide are managed to meet human demands and reduce flood hazards but the resulting flow regime often fails to support ecological and hydrogeomorphic processes. Designing environmental flows (e‐flows) for regulated rivers has been the focus of recent studies, but in the absence of site‐specific monitoring data, it can be difficult to assign flow regimes. Given the recent development of dams throughout China, and the desire to minimize adverse downstream ecological effects, we classified river basins to identify characteristics for improved basin management. The purpose of the classification is to minimize the need for localized data when developing initial evaluations for planning e‐flow prioritization plans. Building on the functional flow framework of managing rivers to deliver environmental water in the right place, time, and amount, we use k‐means consensus clustering to group 185 subbasins of China's Yangtze River into seven hydroclasses (consensus = 0.80). Similar hydrogeomorphic and ecological characteristics are used for the purposes of identifying flow regime components indexed against threatened aquatic species and anthropogenic pressures. This case study can inform water resource management and e‐flow requirements broadly. As hydropower dams are expected to more than double over the next 15 years globally, flexible management strategies that balance ecosystem needs with human demands can support efforts for sustainable development. [ABSTRACT FROM AUTHOR]

The atmospheric wet deposition was higher in subtropical China because of rapid economic growth in past decades and high humidity weather. One-year measurement of wet deposition of organic carbon (C) and dissolved nitrogen (N) was carried out at three sites (Changsha city, Huitong agriculture county, and Dashanchong nature reserve) in Hunan Province. Taking the nature reserve as the control, we make a comparative analysis of the characteristics in atmospheric wet deposition between city and countryside. The concentrations and wet depositions of total and each component of C and N were the lowest in the nature reserve, indicating that human activities significantly increase the atmospheric wet deposition. The concentrations and the wet deposition fluxes of particulate organic C, NO-3-N, and dissolved organic N (DON) were the highest in the city, whereas the corresponding values of dissolved organic C (DOC) and NHþ 4-N were the highest in the countryside. Except for DON, the concentrations of DOC, NHþ4-N, and NO-3-N changed significantly with rainfall characteristics (rainfall amount, intensity, and weather conditions). Our study supplements the wet deposition data as a baseline for exploring future changes in subtropical China. Meanwhile, the lowest wet depositions in nature reserve imply that the reduction of anthropogenic emission is essential to minimizing the adverse effects of the increased atmospheric deposition. [ABSTRACT FROM AUTHOR]

Evaluating the accuracy of gridded weather data is important because these data significantly affect the results of hydrologic simulations. In this study, we evaluated the applicability of Climate Forecast System Reanalysis (CFSR) and China Meteorological Assimilation Driving Datasets for the Soil and Water Assessment Tool (SWAT) model (CMADS) datasets for capturing the hydrologic extreme events in the Fuhe River Basin (FRB) of the Poyang Lake, a typical humid area in eastern China. First, both the CFSR and CMADS temperature and precipitation data obtained from 2008 to 2013 were validated using ground‐based meteorological station data. Then, the SWAT model was driven by the CFSR and CMADS datasets for hydrologic predictions. The results show that both CFSR and CMADS temperature data are of high quality. The CMADS data underestimate precipitation, whereas CFSR data overestimate precipitation. Both datasets have their own advantage and disadvantage to detect extreme rainfall events. For the FRB case study, SWAT models driven by two datasets yield good streamflow simulation results. The CMADS‐driven model performs slightly better than CFSR‐driven model in predicting extreme streamflow events in the simulation time‐period (2009–2013). In general, both the CFSR and CMADS data can be used to obtain satisfactory simulation results for hydrologic predictions. They provide alternatives that enable quickly implementing a hydrologic model in data‐scarce areas. [ABSTRACT FROM AUTHOR]

This study investigates agricultural adaptation to drought for different cropping systems in southern China. The study area was divided into three regions: South China (SC), South of the Yangtze River (SYR), and Southwest China (SWC). An index of agricultural adaptation to drought (D) was established. Our findings indicated that the average total crop water demand varied greatly among the regions from 1961 to 2010 in southern China. The maximum value was found in the SC region, followed by the SYR and SWC regions. The effects of droughts on different crops were noticeable. Frequent droughts were recorded in late rice than in early rice in the SC and SYR regions. Droughts in the SWC region mainly affected winter wheat. Moreover, the effects of droughts on crops varied during different growth stages. More frequent and serious droughts occurred during the crop critical flowering stage. Particularly, the frequency of moderate and severe droughts for late rice in the SYR region was 62% during the critical flowering stage. For the SC and SYR regions, the D values of early rice (0.29 and 0.29) were lower than that of late rice (0.31 and 0.33), respectively. For the SWC region, the D values of winter wheat and rice were both low, with averages of 0.16 and 0.29, respectively. Our study provides interesting insights for improving the drought defense abilities for different cropping systems by changing crop planting proportion on a regional scale in China. Research Impact Statement: Agricultural adaptation to drought for different cropping systems can be estimated based on sown area, actual yield, water demand, and potential evapotranspiration of crop in southern China. [ABSTRACT FROM AUTHOR]

Agricultural drought differs from meteorological, hydrological, and socioeconomic drought, being closely related to soil water availability in the root zone, specifically for crop and crop growth stage. In previous studies, several soil moisture indices ( e.g., the soil moisture index, soil water deficit index) based on soil water availability have been developed for agricultural drought monitoring. However, when developing these indices, it was generally assumed that soil water availability to crops was equal throughout the root zone, and the effects of root distribution and crop growth stage on soil water uptake were ignored. This article aims to incorporate root distribution into a soil moisture-based index and to evaluate the performance of the improved soil moisture index for agricultural drought monitoring. The Huang-Huai-Hai Plain of China was used as the study area. Overall, soil moisture indices were significantly correlated with the crop moisture index ( CMI), and the improved root-weighted soil moisture index ( RSMI) was more closely related to the CMI than averaged soil moisture indices. The RSMI correctly identified most of the observed drought events and performed well in the detection of drought levels. Furthermore, the RSMI had a better performance than averaged soil moisture indices when compared to crop yield. In conclusion, soil moisture indices could improve agricultural drought monitoring by incorporating root distribution. [ABSTRACT FROM AUTHOR]

In this study, we evaluated the European Space Agency Climate Change Initiative soil moisture product v02.1 ( ESA CCI SM v02.1) using in situ observations collected at 547 stations in China from 1991 to 2013. A conventional validation was first conducted, and the triple collocation errors of ESA CCI SM and the European Centre for Medium Range Weather Forecasting reanalysis data were approximately 0.053 and 0.050 m3/m3, respectively. To obtain more reliable validation results, the average soil moisture of the in situ observations per ESA CCI SM pixel was also used as the validation sites. Variance reduction factor ( VRF) was adopted to quantify the accuracy of the soil moisture validation sites, and the average VRF was estimated at 4.88%. The validation results were enhanced by excluding validation sites with VRF errors greater than 5% from the statistical analysis. Although the ESA CCI SM underestimated the in situ observations with a Bias of 0.05 m3/m3, a moderately high correlation coefficient of 0.44 and a relatively small unbiased root-mean-square difference of 0.05 m3/m3 were observed. This study provides information on the utilization of ESA CCI SM for ecological protection, climate change, and hydrological forecasting. It also suggests the adoption of VRF for future error corrections of satellite-based products. [ABSTRACT FROM AUTHOR]

Regarding emerging large-scale reservoir operation models, reports of reservoir operation feedback for hydrologic modeling are rare, and little attention has been paid to flood control. An operation scheme considering multilevel flood control ( MLFC) was first proposed in this study, but more reservoir information was needed. Thus, an alternative scheme was proposed that consisted of a modified version of the reservoir operation scheme in the Soil and Water Assessment Tool Model ( MSWAT scheme). These schemes were coupled to a land surface and hydrologic model system with feedback, i.e., a system in which reservoir operation can affect the subsequent simulation, and were investigated in the Huai River Basin. The results show reservoir storage and peak flow were generally overestimated by the original SWAT reservoir scheme ( SWAT scheme). Compared with the SWAT scheme, the MSWAT scheme successfully reduced the simulated storage and peak flow at the reservoir stations. For the downstream stations, the streamflow simulations were improved at a significance level of 5%. The performances of the MSWAT and MLFC schemes at the reservoir stations were nearly equivalent. Importantly, reservoir operation feedback to hydrologic modeling was necessary because the reservoir operation effects could not be transferred downstream without it. The streamflow simulation of a reservoir station located on a flat plain was less sensitive to feedback than that of a mountain reservoir station. [ABSTRACT FROM AUTHOR]

Mountainous forest areas are vitally important for water supply in dryland regions which suffer from high erosion risk and severe water shortage. Massive afforestation, mainly for erosion control, may reduce the water yield and threaten local water supply security. Moreover, many over-dense forests due to a strict logging ban policy have produced remarkably negative impacts for both forests (e.g., low timber quality, restricted natural regeneration, and high stand instability) and water yield. To satisfy the rapidly increasing demands on water supply and other services, a practical approach for managing forest stands in a multifunctional way, which particularly addresses water yielding, is urgently required. For this purpose, we integrated the existing knowledge and experience, designed an 'ideal' stand structure to represent multifunctional forest ( MFF) and determined its key parameters (a ground coverage of >0.7, a canopy density around 0.7, and an H/ DBH ratio (tree height [m] to the diameter at breast height [cm]) of <0.7). Moreover, a decision process for MFF stand management was recommended as: (1) investigating the site quality; (2) identifying the site-specific main forest functions; (3) quantifying the stand structure; (4) diagnosing the stand structure by comparing with the 'ideal' one; and (5) arranging the functions/structure-oriented management measures. In this way, the water-yielding function can be improved and meanwhile other forest functions can be promoted. [ABSTRACT FROM AUTHOR]

Restored annual streamflow ( Qr) and measured daily streamflow of the Chaohe watershed located in northern China and associated long-term climate and land use/cover data were used to explore the effects of land use/cover change and climate variability on the streamflow during 1961-2009. There were no significant changes in annual precipitation ( P) and potential evapotranspiration, whereas Qr decreased significantly by 0.81 mm/yr ( p < 0.001) over the study period with a change point in 1999. We used 1961-1998 as the baseline period ( BP) and 1999-2009 the change period ( CP). The mean Qr during the CP decreased by 39.4 mm compared with that in the BP. From 1979 to 2009, the grassland area declined by 69.6%, and the forest and shrublands increased by 105.4 and 73.1%, respectively. The land use/cover change and climate variability contributed for 58.4 and 41.6% reduction in mean annual Qr, respectively. Compared with the BP, median and high flows in the CP decreased by 38.8 and up to 75.5%, respectively. The study concludes that large-scale ecological restoration and watershed management in northern China has greatly decreased water yield and reduced high flows due to the improved land cover by afforestation leading to higher water loss through evapotranspiration. At a large watershed scale, land use/cover change could play as much of an important role as climate variability on water resources. [ABSTRACT FROM AUTHOR]