The conflict of the human-water relationships (HWR) has further increased the water-related risks, such as water environment deterioration, water shortages, and even regional violent conflicts for obtaining usable water resources. Knowing how to evaluate and regulate the discordant HWR to form a balanced growth between sustainable socio-economy and water resources protection has become a critical issue in water resources management. The harmony theory method, which provides a new perspective for solving the conflict between humans and water, has been widely used in current studies. However, this method focuses less on the quantitative study of the balance status of HWR. This study proposes a harmony theory-based HWR evaluation method that contains a systematic process of harmony assessment, indicator identification, harmony balance constraints, and harmony regulation for assessing and regulating the discordant HWR. The Henan Province of China, which has a complicated HWR, was selected as a case study to apply and verify the approach proposed in this study. The results indicated that (1) Henan Province showed a poor harmony status. The human–water harmony degree of 18 distinctions in the province varied from 0.41 to 0.76, showing an increasing trend from 2006 to 2018, indicating that the HWR was gradually improving in recent years. (2) The human–water harmony degree showed that HWR in the southwest part of Henan Province, with less human activities, was better than that in its northeast part, which had faster social development. Sanmenxia City, located in the west part of the province, had the highest human–water harmony degree because of the recent water control projects implemented in the city, indicating that human production measures could effectively help improve HWR. (3) At present, Henan Province has serious discordant indicators in these three aspects (water system health, humanistic system development, and human-water system coordination), which proves that it is still facing pressure from both socio-economy sustainable development and water resources protection. Our results provide insight into water resources management in Henan Province and other similar regions.

To achieve the global temperature control target under the background of climate warming, it is necessary to establish a systematic carbon dioxide (CO₂) emission accounting method system in the field of water resources as soon as possible. In this study, the carbon dioxide emission equivalent analysis (CEEA) method for different water resource behaviors (WRBs) is proposed from four dimensions of development, allocation, utilization, and protection, and a function table of CEEA (FT-CEEA) for WRBs is constructed. The FT-CEEA includes CEEA formulae for 16 aspects in four categories of water resource development, allocation, utilization, and protection. The CEEA method is applied to 31 provinces in China. The results reveal that: (1) There are significant spatial differences in the carbon dioxide emission equivalent (CEE) of WRBs in different provinces of China under the influence of various factors such as water supply structure and natural conditions. (2) Reservoir storage, tap water allocation, and wastewater treatment are the main contributors to CEE in the categories of water resource development, allocation, and protection behaviors, respectively. (3) The water resource utilization behavior category has the most significant CO₂ emission and absorption effects, and industrial and domestic water utilization behaviors are the main sources of emission effects. (4) The overall CO₂ emission effect of WRBs is greater than the absorption effect. Measures such as increasing the proportion of hydroelectric power generation, improving ecological water security capacity, and strengthening the level of wastewater treatment and reclaimed water reuse are effective ways to promote the goal of carbon neutrality in the field of water resources.

Water resources management (WRM) is a global strategic issue. Effectively evaluating WRM performance and analyzing its influencing factors have strong practical significance for improving regional WRM performance. Data envelopment analysis (DEA) is one of the most popular models to measure the efficiency of decision-making units (DMUs). Taking regional WRM performance as efficiency DMUs, this paper proposes the indicator system to quantify WRM performance from the perspectives of resource endowments, economic and technological development, and ecosystem protection. The WRM performance of 31 provincial administrative regions in mainland China from 2013 to 2019 are measured, and the temporal and spatial changes are explored using the window DEA model and the Malmquist index model. Finally, the Tobit model is used to quantitatively analyze the affecting factors. The results indicate that: (1) in 2015 and 2019, WRM performance of Sichuan, Shaanxi, Xinjiang, Inner Mongolia, and Guangxi were slightly higher than that in other years, and the areas with more room for WRM performance improvements were areas with abundant water resources; (2) from 2013 to 2019, China’s overall WRM performance showed a slow rise, and there were obvious fluctuations in 2018; (3) the improvement in WRM performance was primarily the result of an improvement to comprehensive technical efficiency changes (EC), whereas technological progress changes (TC) have largely restricted China’s WRM performance; (4) the main influencing factors of WRM performance in China were as follows: industrial development level, water resources utilization rate, and urban sewage discharge per capita.

The human–water relationship in the Yellow River Basin is extremely complex, and the human–water relationship discipline is a powerful tool to solve difficult problems caused by the complexity. This study firstly analyzes the historical evolution of the human–water relationship in the Yellow River Basin. Secondly, we summarize some representative problems in dealing with the human–water relationship. Then, on the basis of discussing the main contents of the human–water relationship discipline, the possible solutions to the difficult problems are discussed. Taking the Yellow River water distribution dilemma as an example, we carry out a detailed application. Finally, the possibility of applying human–water relationship discipline to complex basin research is analyzed, and the future research prospects of the discipline are put forward. Results reveal that: (1) River diversion and unreasonable human activities are the main driving factors for the ecological evolution of the Yellow River Basin. In addition, the basin is currently in the “Protective coordination stage”. (2) The complexity of the human–water relationship is the root of many difficult problems, and forming a sound disciplinary system of human–water relationship discipline is the key to breaking through these difficult problems. (3) The Yellow River water distribution scheme based on human–water relationship discipline is consistent with the current water use pattern of the basin. (4) The theory and method system of human–water relationship discipline is also feasible and universal for other complex basins.

China has proposed “ecological conservation and high-quality development of the Yellow River Basin” to a major national strategy, which puts forward higher requirements for water, energy, and food along the Yellow River (TYR). However, the water–energy–food nexus (WEF) system in TYR basin is very complicated. Based on the theory and method of harmonious regulation, this paper puts forward a new WEF harmony framework (WEFH) to study the harmonious balance of WEF in TYR. WEFH cannot only evaluate the harmonious balance of WEF, but also identify the main influencing factors, and further study the harmonious regulation of WEF. For the key steps of regulation and control, we provide a variety of methods to choose from in this framework. In practice, we apply this framework to the regulation of WEF in the nine provinces along TYR. The results show that during 2005–2018, the harmony degree of WEF in the nine provinces along TYR is between 0.29 and 0.58. The harmony degree of WEF has improved over time, but there is still a lot of room for improvement. Among them, per capita water resources, hydropower generation ratio, carbon emissions, and another 12 indicators have great influence on the harmony of WEF. We have established eight control schemes for nine of these indicators. In eight control schemes, most areas have reached a moderate level of harmony degree. These results show that the framework proposed in this paper is helpful to the comprehensive management of regional WEF and provides a viable scheme for the optimization of WEF.

Enhancing the level of water use and alleviating the constraints of water shortage on economic and social development are powerful supports to realize the harmonious balance of water and economic society. In this study, the data envelopment analysis (DEA) window analysis method is applied to the study of water use level, and the SBM-DEA model (slack based measure, SBM) is combined to explore the spatial and temporal evolution characteristics of composite water use index (CWUI) in nine provinces from 2012 to 2018. The Malmquist index model is used to decompose the intrinsic causes of total factor productivity (TFP) changes, and the spatial matching degree calculation method is applied to study the matching degree between CWUI and economic and social development levels (E-SDL). The results showed that: (1) the overall trend of CWUI in the nine provinces from 2012 to 2018 was increasing, with significant spatial variability in water use levels; (2) the improvement of TFP of water in the nine provinces was mainly driven by technological change (TC), and the main factor limiting the improvement of TFP of water was technical efficiency change (EC); (3) E-SDL of the nine provinces showed an increasing trend, with the spatial distribution characteristics of decreasing E-SDL of the downstream, midstream and upstream provinces in sequence; (4) the degree of matching between CWUI and E-SDL shows strong regional differences, with different types of matching.