Research on the construction of a human-water harmony model in the Yellow River Basin

On the 18th of September, 2019, General Secretary Xi Jinping, during his journey to Henan Province, put forward a national plan for the safeguarding of the environment and the advancement of the Yellow River Basin, a critical factor in the development of China in a unified and superior manner (Xi, 2019). In October 2021, the State Council promulgated the Outline, emphasizing that adhering to ecological priority and green development will make the Yellow River Basin an essential barrier to national ecological security. The Yellow River Basin's critical role in China's economic and social growth and ecological atmosphere has been increasingly acknowledged by the public due to the country's focus on the basin (The Central Committee of the Communist Party of China State Council, 2021).

Regarding the ecological environment, the total water resource of the Yellow River in 2020 was 664.89 billion m³, making up 20.54% of the country, with 506.9 mm of annual precipitation. The total water consumption was 125.87 billion m³, making up 21.6% of the country, of which 11.49 billion m³ was used for artificial ecology, accounting for about 37.4% of the country, and 19.53 billion m³ were used for domestic use, accounting for about 22.6%. The utilization rate of water resources development was as high as 80%, far exceeding the alert line of 40% in other basins (Xi, 2019). The Yellow River Basin not only has a high utilization rate of water resources but also has severe pollution. As the 21st century dawned, the economy's growth had yet to be accompanied by a focus on water protection. The factories discharged high-concentration industrial sewage into the Yellow River, coupled with increasingly severe domestic sewage pollution, which worsened the increasingly harsh water environment. In 2020, the Yellow River's four and below four types of water bodies accounted for 23% of the total length of the Yellow River (Zhao, 2022). Concerning economic and social development, the GDP of the nine provinces along the Yellow River in 2020 would be 25.39 trillion Yuan, accounting for 24.99% of the country. The total population was 421 million, representing 29.84% of the country. Among them, 251 million were urban residents and 170 million were rural residents. The urbanization rate was 59.62%, lower than the national average of 63.89%. The number of medical beds was 2,876,333, accounting for about 31.6% of the country, and the education expenditure was 129,621 billion Yuan, accounting for about 24.4% of the country (Li et al., 2022a). In this context, studying human-water harmony was significant for implementing the decision-making and deployment of the Party Central Committee's Outline and promoting ecological protection and high-quality development in the Yellow River Basin. Throughout the research progress of human-water harmony at home and abroad, the index system and model of human-water harmony achieved specific results, which were of great significance for further development and improvement of the theoretical research of human-water harmony. However, the evaluation index system and quantitative approach to human-water harmony were still exploratory. There needed to be a unified theoretical framework, more systematic and recognized evaluation index systems and quantitative evaluation methods (Kang, 2013).

In summary, this paper will utilize the coupling coordination degree model to select 23 indicators pertinent to the human-water system from two significant systems of human and water and then utilize provincial-level data from the nine provinces of the Yellow River Basin from 2001 to 2020 to quantify the coupling coordination degree of human-water harmony. A theoretical basis and data can bolster the Yellow River Basin's realization of human-water harmony and sustainable development.

In recent years, ecological protection and high-quality development of the Yellow River Basin have become a hot issue of social concern. The human-water relationship has also become the focus of scholars' research. The following two aspects are reviewed for studying human-water harmony: the advancement of human-water harmony research and the research methods related to the human-water relationship.

In 1947, Leopold published A Sand County Almanac, which proposed that based on protecting nature, water, land, animals, and plants are the masters of nature, and integrated ecological ethics into the study of man and nature (Leopold, 1949). In 1972, the Club of Rome issued the Limits to Growth, which warned us to adhere to environmental protection in economic development (Meadows et al., 1972); in 1987, the 42nd United Nations General Assembly passed the Our Common Future, the report proposed that human and nature should live in harmony, we should adhere to the road of sustainable development (Brundtland 1987); in 1995, Falkenmark explored the bond between human society and water resources, and established an integrated water resources management model to maintain the balance between human and water and achieve sustainable development (Falkenmark et al., 1989; Falkenmark & Lan, 2021); in 2006, Taikan explored the connection between water and human based on the virtual water model, and proved the vital relationship between human and water (Oki & Kanae, 2006). Although the research on human water is relatively early abroad, the concept of human-water harmony must be advanced.

Domestic scholars’ research on the connection between humans and water started late. In 1984, Chinese ecologist Ma established a social-economic-natural composite ecosystem to analyze the problems encountered in nature and social development (Ma & Wang, 1984); on November 6, 1999, Wang first proposed the harmonious coexistence of humans and nature at the work conference (Dong et al., 1999). In 2004, the theme of China Water Week was ‘harmony between humans and water’. In 2007, when studying the relationship between man and water, Qi proposed that the most important thing in dealing with the relationship between man and nature is to do an excellent job of harmony between man and water (Qi, 2007); in 2008, Zuo proposed the concept of human-water harmony (Zuo et al., 2008), and in 2009, game theory was applied to the relationship between the two, thereby demonstrating the need and practicality of incorporating game theory into human-water harmony (Zuo & Zhao, 2009).

The human-water relationship involves many factors, such as economy, environment, and population, and has significant uncertainty. Domestic and foreign scholars have conducted much research on this. The commonly used evaluation models are the environmental Kuznets, grey correlation, coupling coordination degree, fuzzy comprehensive evaluation, and data-driven models.

The American economist Grossman and Krueger proposed the environmental Kuznets model and applied it to evaluate the relationship between the environment and the economy (Grossman & Krueger, 1991). Li used the environmental Kuznets curve model to construct an econometric model of industrial wastewater and per capita GDP in Jiaxing City. They analyzed the relationship between per capita GDP and industrial wastewater (Li et al., 2022b). The principle of the environmental Kuznets model is regression analysis and curve fitting. This method is simple and easy to use. However, it is only suitable for single-factor analysis based on empirical observation and uses a large number of second-hand data, resulting in a relatively significant impact on the results (Fu & Lin, 2010).

Chinese scholar Deng founded the grey correlation model. In 1984, Deng established a quantitative model based on the grey correlation degree to analyze the relationship between abstract systems such as society and economy (Deng et al., 1982; Deng, 1984). Li used the grey correlation model to analyze the coupling mechanism of urbanization and the ecological environment in Hohhot and measured the coupling coordination degree (Li & Xie, 2015). The grey correlation model method is simple and operable, but the weight greatly influences the evaluation results.

German physicist Professor Hermann proposed the coupling coordination degree model in 1971, which analyzes the interaction between two or more systems through joint movement, interaction, mutual influence, and synergy. In 1996, Wu established the coordination degree model of the environmental-economic system (Wu et al., 1996). The model includes a variety of approaches, such as the analytic hierarchy process, principal component analysis, and information entropy weight method (Zhou, 2019). The analytic hierarchy process is simple and systematic but too subjective to be detected. The principal component analysis method can eliminate the influence between the evaluation indicators and reduce the influence between the selected indicators. However, this method must ensure that the leading indicators account for a higher impact and that the leading indicators affect the positive and negative load. The information entropy weight technique can prevent the divergence caused by subjective factors, and the model is uncomplicated.

The fuzzy comprehensive evaluation model is a theoretical method proposed by Professor L.A. Zadeh of the University of California, which is used to study the problem of ambiguity or uncertainty. In 1987, Fu used this model to evaluate water pollution. After that, the intricate connection between the water and human system is often measured by the index membership degree and system comprehensive membership degree (Fu, 1987). Liu used the fuzzy comprehensive evaluation model to evaluate Xi'an's harmonious relationship with people and water (Liu & Song, 2009). The model is simple and easy to grasp and can quantify the qualitative problems and improve the accuracy of evaluation. However, the membership function of this method has yet to reach a unified consensus. The weight coefficient will be more significant when too many indicators exist, resulting in evaluation failure.

Data-driven model is a mathematical model based on big data using data-driven methods. In 2006, Hinton's multi-hidden layer deep neural network structure gave the main framework of deep learning algorithms for research in many fields, such as hydrology (Hinton et al., 2006). Deep learning is a method based on probability theory to find the optimal solution. It has strong practicability and learning ability and can avoid the error caused by weight. However, this method has a high cost and complex technology, often used in high-precision research. Kuehnert used a deep learning model to predict the hourly water demand for suppliers in the next 24 h (Kühnert et al., 2021).

In addition, Yang constructed a coordination degree model of the ecological environment and high-quality development of the regional economy and empirically analyzed the coordination between the ecological environment and high-quality development of the regional economy in 31 regions of China in 2018 (Yang & Wang, 2020). Parsa constructed a social hydrological model based on agent-based modeling (ABM) and theory of planned behavior (TPB) (Pouladi et al., 2019).

Reviewing the research progress of human-water harmony at home and abroad (Choi et al., 2017; Liu et al., 2021; Li & Qin, 2022; Zhang et al., 2022a), human-water harmony has achieved many valuable research results. There are two main aspects of research. One is the measurement of human-water harmony, and the other is to explore the influencing factors of human-water harmony. In the literature on influencing factors, scholars mainly use urban and rural economic development, water resources status, education, medical investment, and other factors as control variables to explore. The conclusions align with the study area's characteristics. The models used to measure human-water harmony mainly include the environmental Kuznets, coupling coordination degree, fuzzy comprehensive evaluation, and data-driven models. However, there are still some limitations in the existing research.

• (1)

  Although the literature has explored harmony, only a few pieces of literature directly consider the impact of life expectancy on the whole basin. Life expectancy is an essential indicator to measure the health status of countries and regions. Considering life expectancy as an indicator is in line with the form and development of the Yellow River and can more comprehensively reflect the coordinated development status and related problems in the region (Cai, 2012).

• (2)

  This paper selects the provincial panel data of nine provinces in the Yellow River Basin from 2001 to 2020, which can analyze the spatial and temporal evolution of human-water harmony in each province on a larger scale.

• (3)

  There are many models in the literature to explore harmony. These models have apparent advantages, but some things could be improved. The environmental Kuznets model uses a large amount of second-hand data, which leads to the result being greatly affected by interference. The grey correlation model is greatly affected by weight. Using the fuzzy comprehensive evaluation model, when there are too many selected indicators, the weight coefficient will be caused.

This paper used the coupling coordination degree model based on the information entropy weight method as the research method for human-water harmony in the Yellow River Basin. The spatial statistical analysis of harmony used ArcGIS software. Entropy theory, which promotes and applies information entropy, was used to measure the system's level of disorder. The information entropy could determine the index's weight in the comprehensive evaluation. The index's weight was determined by the more significant the information entropy of the index, which was proportional to the value of the object to be evaluated on it; the more significant the discrepancy between its values, the lower the entropy.

• (1)
  Data standardization

  

  (1)

  

  (2)

x_ij denotes the sample value of the indicator j in region i; max and min are the maximum and minimum values of j, respectively.

• (2)

  Determination of weights

e_j was the information entropy of the indicator j, K = 1/ln n was a non-constant number, and 0 ≤ e_j ≤ 1.

f(x) and g(y) denote the combined scores of the water system and human system, respectively.

In this study, it was considered that the human system and water system were equally important, so α and β were taken as the same weight, that is, α = β = 0.5.

This study used the data from nine provinces of the Yellow River from 2001 to 2020 to analyze the harmony between humans and water. The original data are derived from the China Statistical Yearbook, Water Resources Bulletin of Nine Provinces, Yellow River Water Resources Bulletin, and the statistical yearbook of nine provinces. Very few missing data were estimated by the appropriate method.

• (1)

  From the point of view of human-water harmony, from 2001 to 2020, China's human-water relationship was on the rise, from reluctant coupling coordination to good coupling coordination. In 2008, the degree of human-water harmony entered a primary coupling coordination in an all-around way, entered a moderate coupling coordination in 2014, and entered an excellent coupling coordination in 2017.

• (2)

  The degree of human-water coupling coordination in Qinghai, Gansu, and Sichuan provinces shows a clear upward trend in time series. It has gone through six stages: on the verge of a dysfunctional decline barely coupling coordination, primary coupling coordination, moderate coupling coordination, good coupling coordination, quality coupling coordination, and reached the quality coupling coordination level in 2020.

• (3)

  From 2001 to 2011, the human system's comprehensive index was inferior to that of the water system's comprehensive index. In 2003, the comprehensive index of human and water systems was the largest. From 2012 to 2020, the human system's comprehensive index was higher than the water system. However, in 2015, the two indices diverged significantly.

• (1)

  Continue to deepen the existing development strategy and actively sum up experience to bring about a harmonious growth of both humans and water in the Yellow River Basin.

Continue to increase investment in education, give priority to public education resources to underdeveloped areas, achieve educational equity, absorb high-quality talents, and increase the proportion of people with a junior college education or above; increase investment in the field of medical care and old-age care, appropriately increase the subsistence allowances and five guarantees, improve the security system, and narrow the gap in the quality of life between rural residents and urban residents; industrial structures should be upgraded, scientific and technological advances should be invested in, and industrial water resources should be utilized more efficiently.

• (2)

  Strengthen the protection and oversight of the ecological environment, and improve environmental protection awareness.

The government and citizens should be encouraged to become more conscious of the environment, investment in environmental pollution and governance should be augmented, and environmental supervision and law enforcement should be strictly enforced. The provinces will link environmental protection with other industrial sectors to increase the number of illegal sewage enterprises.

Investigation: Y.S., S.Y.; data curation: S.Y., W.C., X.W., C.F.; writing – original draft preparation: Y.S., S.Y.; writing – review and editing: Y.S., S.Y.; All authors have read and agreed to the published version of the manuscript.

This work was financially supported by the Department of Science and Technology in Henan Province (232102320278). The research was partially supported by Training Plan for Young Backbone Teachers in Colleges and Universities in Henan Province (2019GGJS098 and 2020GGJS098).

All relevant data are included in the paper or its Supplementary Information.

The authors declare there is no conflict.