Research on Water Rights Allocation of Coordinated Development on Water–Ecology–Energy–Food

Abstract

Water rights trading is an important way to solve the problem of water shortage by market mechanism. The allocation of water rights among ecological water, energy water, and grain planting water are the basis of the regional water rights trade. In this paper, the concept of coordinated development of water–ecology–energy–food is proposed. We build a water rights allocation model with fairness, efficiency, and coordinated development as the goal, to achieve water security for various industries. Taking Yinchuan city as an example, the results showed that compared with the current water rights the water rights of life increased by 1.07%, the water rights of ecology increased by 1.85%, the water rights of energy industry decreased by 1.09%, the water rights of food planting decreased by 3.27%, the water rights of other agriculture increased by 0.83%, and the water rights of the general industry increased by 0.65%. After the allocation of water rights, the cooperativity of water–ecology–energy–food increased by 7.56%, and the total value of water resources in various industries increased by 2.31 × 10⁸ CNY. A new water rights allocation model is developed in this paper, which can provide a reference for the allocation of water rights among regional industries.

1. Introduction

Water, ecology, energy, and food form the basic conditions of human survival [1], and these four resources are associated with each other [2,3]. The coordination and effective uses of them not only alleviates the resource crisis [4], but also promotes the coordination of the urban social economy [5]. As a basic natural resource, strategic economic resource, and an ecological environment of important control elements [6], water can become the carrier of the coordinated development of effective regulation and the control of various resources. Reasonable water rights allocations between industries can solve the contradiction between supply and demand of regional resources [7]. It is also an important measure to promote local water–ecology–energy–food coordinated development and to effectively promote the ecological protection and high-quality development of the Yellow River Basin.

The middle and upper reaches of the Yellow River Basin Is a typical arid and semi-arid area due to the shortage of water resources and the fragile ecological environment. At the same time, this region is also an important energy production base and food planting base. Water, ecology, energy, and food are important influential factors of the regional social and economic development. The scientific analysis of the coordination among the four resources can play an important role in solving the contradiction between the supply and demand of regional resources and promoting the sustainable development of the regional economy. Many scholars have studied the coordination between regional resources. In the water-ecological-energy-food system, the relationship among water-energy-food (WEF) has been extensively studied worldwide [8,9,10]. The study of the WEF system consists mainly of two aspects: firstly, the link between the energy and water consumption, the food industry relations, and the feedback mechanism [11,12,13] (for example, such as Wu [14] and Jesus [15] revealed the associated mechanism to establish a link between the WEF model using integrated resource management for an area). Secondly, is the comprehensive safety assessment of the regional water-energy-food system (see Chen [16] and Zhang [17], respectively) on China’s Inner Mongolia and China’s global water-energy-food comprehensive safety evaluation. The development and utilization of water, food production, and energy production are directly affecting the state of the local ecological environment. It is very urgent to protect the ecological environment. However, few scholars add ecology to WEF for discussion. In this study, the ecological security is added in the water-energy-food system in order to form the water-ecological-energy-food (WEEF) composite system.

In the water–ecology–energy–food system, water, with its unique liquidity and circularity, becomes the link of the WEEF system. Reasonable water rights allocations can effectively relieve the contradiction between the water industries [18,19], and it can be an important means to promote the coordinated development of water–ecology–energy–food in the region. The water rights allocation mode aims at the coordinated development of water, ecology, energy, and food, and is an important measure to solve the increasingly prominent contradiction [20] among ecology–water, energy–water, and food–water. If we take water resources as the carrier and the object of regulation, and rationally allocate the water rights of ecology, energy, and food to make WEEF resources mutually promote development, we can realize mutual benefit and a win-win of multiple resources, and achieve the goal of coordinated development of water, ecology, energy, and food.

In this paper, the coordinated developmental relationship of regional water, ecology, energy, and food is analyzed. We take water as the control carrier and water rights allocation as the means to promote the coordinated development of water, ecology, energy, and food. The water rights allocation model is constructed according to the maximum water efficiency, the most equitable distribution, and the highest collaborative of water–ecology–energy–food. Water rights must be allocated to life, ecology, the energy industry, food planting, other agricultural and the general industrial six water industries. The water rights allocation model of coordinated development on water–ecology–energy–food is put forward in this paper. It will provide reference and basis for the optimal allocation of water rights and water rights trading in the region, and help promote the concept of coordinated development of water–ecology–energy–food.

2. Materials and Methods

2.1. The Correlation Theory

2.1.1. The Concept and Basic Principles of Water Rights Allocation

Water rights is a type of property rights, which has a different connotation after a long time of formation and development in different countries. In China, water rights are considered to be the ownership and the rights to use water resources [21]. China’s water law stipulates that the ownership of water resources belongs to the state, so what is actually allocated is the right to use the water resources. Water rights allocation refers to the distribution process of water resources use of a river basin or a region according to certain rules and mechanisms. A water rights distribution system can solve the scarcity of water resources and improve the efficiency of water resources utilization. It is an effective method to realize the optimal management of water resources.

The principles of water rights allocation generally include fairness, efficiency, basic domestic water security, basic ecological water security, etc. In order to ensure the safety of production water in ecological restoration, key energy industries, and food planting areas, the water rights allocation principle of coordinated development of water-ecology- energy-food is put forward in this study. This principle is helpful to solve the contradiction between the supply and demand of water resources among regional industries and promote the harmonious development of regional key industries.

2.1.2. The Definition of Coordinated Development on Water–Ecology–Energy–Food

Haken [22] believes that “coordinated development” is a process of co-evolution and development in a positive direction through mutual influence, interaction, continuous feedback, control, and adjustment among units. Water, ecology, energy, and food are important basic resources in the development of economy and society, as they interact with each other and are connected with each other. The ultimate goal of the coordinated development of water, ecology, energy, and food is to fully and reasonably develop and utilize various resources, meeting the needs of population growth, urban development, and maintaining economic, social, and ecological environment stability.

Based on this, the coordinated development of water–ecology–energy–food can be understood as: aiming at the rational development and sustainable utilization of water, ecology, energy, and food resources. Through the mutual cooperation and mutual feed linkage between the resource subsystems, the resources promote the development of each other, so as to achieve a mutually beneficial and a win-win situation of multiple resources. The circularity and scarcity, the mobility within and between resources, and the infinity of social demand make water resources an indispensable carrier in the construction of the water–ecology–energy–food composite system. Therefore, water resource is taken as the control object in this paper, to achieve the purpose of the coordinated development of water–ecology–energy–food. This process of mutual promotion and common development among resources can be called the coordinated development of resources. The coordinated development of various resources is of great significance to human survival, social progress, economic development and the sustainable development of maintaining a good ecological environment.

2.2. Regional Overview of the Study Area

Yinchuan, as the capital of Ningxia Hui Autonomous Region, is an important central city in Northwest China, and an important trade town on the ancient Silk Road. By the end of 2020, Yinchuan had a total area of 9025.38 km², and a resident population of 2.29 million. On the water resources situation, the average annual precipitation in Yinchuan is only 210 mm. The Yellow River flows through the center of Yinchuan, bringing a large number of water resources, as nearly 90% of urban water comes from the Yellow River. The per capita available water resource in Yinchuan is 640 m³, which is 1/11 of the global per capita. Yinchuan crosses the northwest arid region and the eastern monsoon region, so it has various types of ecological uses. However, the natural ecosystem function of Yinchuan is on the low side, and the ecological environmental capacity is small. Its human activities have a strong influence on the environment, and in some areas cause serious environmental degradation. In terms of energy exploitation and processing, there is a large national coal production base, the “West-to-East Power Transmission” thermal power base and coal chemical industry base in Yinchuan. In terms of food planting, Yinchuan is located in the Yellow River irrigation area, which is an important food planting area. The location, terrain, and water system in Yinchuan are shown in Figure 1.

2.3. Construction of the Water Rights Allocation Model

To build a water right allocation model, the allocation principle should be established first [21]. A multi-objective water rights allocation model is established by taking the principles of fairness, efficiency, and coordinated development of water–ecology–energy–food as the objective function, and the principle of water security in the industry as the constraint.

2.3.1. The Objective Function of Fairness

The objective function of fairness is reflected by the satisfaction function of water rights allocation in each industry. The smaller the value, the smaller the difference in satisfaction with the allocated water rights among industries; that is, the fairer the water rights allocation between the industries is. The equation is as follows:

$$\max RF=\max {{\displaystyle \sum _{h=1}^H\left(\frac{W_h/W{Q}_h-{\displaystyle \sum _{h=1}^H{W}_h/WQ}}{{\displaystyle \sum _{h=1}^H{W}_h/WQ}}\right)}}^2,$$

(1)

where RF is the objective function of fairness; W_h is the allocated water rights of industry h (m³); WQ_h is the current water rights of industry h (m³); and WQ is the sum of current water rights of various industries (m³).

2.3.2. The Objective Function of Efficiency

The objective function of efficiency needs to quantify the water resource benefits of various industries, to make the total benefit of water resources after allocation as high as possible. There are differences in the quantitative methods for the benefits of water resources in different fields, so it is necessary to select appropriate methods to uniformly quantify the benefits of water resources in various industries. The emergy analysis method is chosen to quantify the benefits of water resources in this paper. Emergy is a metric created by the American ecologist Odum [23,24], which uses solar energy as a standard to convert different substances and energy into the solar energy that forms it. The emergy method can convert the water resources benefits of various industries into the same dimension for analysis, making the distribution results more real and reliable.

(1)

Water resources benefit life, energy, food planting, other agricultural systems, and the general industry

The water resource benefits of the living, industrial, and agricultural system are reflected in the contribution of water resources as a factor of production in the activities of each system [25]. The water resource benefit of the ecosystem is calculated separately according to the benefit of different ecological water use. By analyzing the energy input and output of the system, the ratio of water resource benefit input to the total input energy of all production factors in each system, it can be multiplied by the total output emergy of the system to obtain the output emergy of water resources. The equation is:

$$E{M}_h=\frac{E{M}_{Wh}}{E{M}_{INh}}\times E{M}_{OUTh}.$$

(2)

where EM_h is the output water emergy of industry h (sej), that is, the objective function of efficiency in h industry, including life (EM_L), energy industry (EM_N), food planting (EM_F), other agriculture (EM_O), general industry (EM_I); EM_Wh is the input water emergy of industry h (sej); EM_INh is the total input emergy of industry h (sej); EM_OUTh is the total output emergy of industry h (sej).

(2)

The water resources benefit for ecology

In this paper, urban ecological water use is divided into three parts: artificial lake replenishment, urban road sprinkling, and green space irrigation. Artificial lake replenishment can produce dilution and purification benefit. Watering urban roads can produce cooling and humidifying benefit and dust removal benefit. Irrigation of urban green space is a necessary condition for the growth and development of green plants, which will bring benefits of carbon fixation and oxygen release. The equation is:

$$\begin{array}{l}E{M}_E=W_{Ea}\times {\tau }_{DB}+W_{Eb}\times L\times {\tau }_E+W_{Eb}\times \Delta P{M}_{10}\times {\tau }_D\times 48.62\%\\ +\left(B_C\times {\tau }_C+B_O\times {\tau }_O\right)\times \frac{W_{Ec}}{W_{Ec}+W_P}\end{array},$$

(3)

where EM_E is water emergy of ecology system (sej), that is, the objective function of efficiency in ecology; W_Ea is the quantity of artificial lake replenishment in ecological water (m³); τ_S is the transformity of surface water (sej/m³); W_Eb is the quantity of urban road sprinkling in ecological water (m³); L is the latent heat of evaporation (J/g), L = 2507.4−2.39 T, T is the average annual temperature in the study area (°C); τ_E is the transformity of evaporation (sej/J); ΔPM₁₀ is the variable quantity of PM₁₀ before and after sprinkling (μg/m³); τ_D is the transformity of dust (sej/μg); 48.62% is the control efficiency of sprinkling on dust particles [26]; B_C is the amount of carbon fixation (g); B_O is the amount of oxygen release (g); τ_C and τ_O are the transformities of carbon fixation and oxygen release (sej/g) [25]; W_Ec is the quantity of green space irrigation (m³); W_P is natural precipitation (m³).

(3)

The efficiency objective function of water rights allocation established according to the above items is:

$$\max RS=\max \left(E{M}_L+E{M}_E+E{M}_N+E{M}_F+E{M}_O+E{M}_I\right),$$

(4)

where RS is the objective function of efficiency.

2.3.3. The Objective Function of Coordinated Development

In order to demonstrate the principle of water–ecology–energy–food coordinated development in the process of water rights allocation, the existing coordinated development status can be quantified into a specific value, which is called the coordinated development index. The greater the coordinated development index is, the better the coordinated development status of the four resources is. The maximum index of coordinated development is taken as the objective function. The comprehensive evaluation method is used to calculate the coordinated development index. The comprehensive evaluation method [27,28] can select objective indicators from the regional economic, social, and ecological environment. Multiple indicators can be evaluated systematically and normatively at the same time, and the evaluation results can be quantified. Finally, a general numerical value is formed, and the evaluation purpose is achieved through numerical comparison.

(1)

The selection of comprehensive evaluation indicators for coordinated development is shown in

Table 1. The comprehensive evaluation indicators of water–ecology–energy–food coordinated development.

System	Indicator	Unit	Indicator Attribute
Water	Per capita water resources (a1)	m3/pc	+
	Utilization ratio of water resources (A2)	%	−
	Utilization ratio of groundwater resources (A3)	%	−
	Utilization ratio of unconventional water (A4)	%	+
	Water consumption of 104 CNY GDP (A5)	m3/104 CNY	−
Ecology	Annual precipitation (b1)	mm	+
	Green space coverage rate (B2)	%	+
	Per capita green area (B3)	m2/pc	+
Energy	Per capita energy production (c1)	tce/pc	+
	Energy consumption of 104 CNY GDP (C2)	tce/104 CNY	−
	Energy self-sufficiency rate (C3)	%	+
Food	Per capita cultivated area (d1)	m2/pc	+
	Per capita food production (D2)	kg/pc	+
	Proportion of added value in primary industry (D3)	%	−
	Food self-sufficiency rate (D4)	%	+
Water–ecology	Proportion of water rights in ecology (ab1)	%	+
Water–energy	Water consumption of per unit energy production (ac1)	m3/tce	−
	Proportion of water rights in energy industry (AC2)	%	−
	Proportion of water rights in general industry (AC3)	%	−
Water–food	Proportion of water rights in food planting (ad1)	%	−
	Irrigation water consumption of Per unit cultivated area (AD2)	m3/hm2	−
	Coefficient of irrigation water effective utilization (AD3)		+
Ecology–energy	Proportion of clean energy generation (bc1)	%	+
Ecology–food	Application amount of chemical fertilizer Per unit cultivated area (bd1)	t/hm2	−
Energy–food	Agricultural machinery power per unit cultivated area (cd1)	kw/hm2	−
	Proportion of energy consumption in primary industry (CD2)	%	−
Economic	Per capita gdp (j1)	104 CNY/pc	+
	GDP growth rate (J2)	%	+
	Proportion of added value in tertiary industry (J3)	%	+
Social	Proportion of water rights in life (h1)	%	+
	Rate of population growth (H2)	‰	−
	Engel Co-efficient (H3)	%	−
	Urbanization rate (H4)	%	+
	Population density (H5)	pop/km2	−
Environment	Sewage treatment rate (z1)	%	+
	Greenhouse gas emission per 104 CNY GDP created (Z2)	kg/104 CNY	−

.

(2)

The coordinated development index can be quantified with the entropy weight method:

(A)

Normalization treatment

when the indicator is positive

$$y_{ij}=\frac{x_{ij}-\min \left(x_j\right)}{\max \left(x_j\right)-\min \left(x_j\right)},$$

(5)

when the indicator is negative

$$y_{ij}=\frac{\max \left(x_j\right)-x_{ij}}{\max \left(x_j\right)-\min \left(x_j\right)},$$

(6)

where y_ij is normalized data; max(x_j) is the maximum indicator j in n years; and min(x_j) is the minimum indicator j in n years.

(B)

The calculation of the index

Calculate the weight of the indicator in the year i under the index j:

$$P_{ij}=\left(\frac{y_{ij}}{{\displaystyle \sum _{i=1}^n{y}_{ij}}}\right),i=1,2,\dots ,n.$$

(7)

Calculate the information entropy of indicator j:

$$E_j=-\frac{1}{\ln n}\times {\displaystyle \sum _{i=1}^n\left(P_{ij}\times \ln \left(P_{ij}\right)\right)}.$$

(8)

Determine the weight of indicator j:

$$M_j=\left(\frac{1-E_j}{k-{\displaystyle \sum _{j=1}^k{E}_j}}\right),j=1,2,\dots ,l.$$

(9)

Calculate the coordinated development indicator G_i in the year i:

$$G_i={\displaystyle \sum _{j=1}^k\left(M_j\times y_{ij}\right)}.$$

(10)

(C)

The objective function of coordinated development

$$\max RG=\max G,$$

(11)

where RG is the objective function of the coordinated development on water–ecology–energy–food.

2.3.4. The Constraints of Industry Water Rights

The current water rights security for industrial and agricultural production and the water rights security for future life are taken, as constraints in this model. Domestic water is the sum of water for the daily life of residents and urban public water. Ecological water includes artificial lake replenishment, urban road sprinkler, and green space irrigation. The energy industry includes coal mining, coal washing, coking, crude oil refining (including gasoline, diesel, kerosene and other crude oil processing industries), and thermal power generation. Food planting includes the cultivation of rice, corn, wheat, and beans (potatoes do not grow in Yinchuan). Other agriculture includes planting industries other than food crops, as well as timber, livestock products, and fishery products. Other agriculture includes farming other than food crops, as well as timber, animal, and fish products.

(1)

The constraints of water rights of life:

$$W_L\ge {\left(1+N_U\right)}^a{P}_U\times Q_U+{\left(1+N_R\right)}^a{P}_R\times Q_R+GD{P}_{UP}{\left(1+N_{UP}\right)}^a\times M_{GDP},$$

(12)

where W_L is the water rights of life (m³); P_U, P_R are the number of urban people and rural people; N_U, N_R are the population growth rate of urban and rural; Q_U, Q_R are the per capita domestic water quota for urban and rural; GDP_UP is the GDP of urban public industry; N_UP is GDP growth rate of urban public industry; and M_GDP is the water consumption per CNY 10,000 GDP; a is the year for future domestic water security.

(2)

The constraints of water rights of ecology:

$$W_E\ge S_G\times M_G+S_L\times \left(E_L+K_L\right)+S_R\times M_R,$$

(13)

where W_E is the water rights of ecology (m³); S_G is the greening coverage area; M_G is the quota for greening irrigation; S_L is the area of artificial lake; E_L is the evaporation supply quota of local lakes; K_L is the infiltration supply quota of local lakes; S_R is the area of urban roads; and M_R is quota of urban road sprinkling.

(3)

The constraints of water rights of energy industry:

$$W_N\ge {\displaystyle \sum \left(R_{Nk}\times M_{Nk}\right)},$$

(14)

where W_N is the water rights of energy industry (m³); R_Nk is the production of energy k; M_Nk is the water quota for the exploitation or processing of energy k.

(4)

The constraints of water rights of food planting:

$$W_F\ge {\displaystyle \sum \left(R_{Fk}\times M_{Fk}\right)}.$$

(15)

(5)

The constraints of water rights of other agriculture:

$$W_O\ge {\displaystyle \sum \left(R_{Ok}\times M_{Ok}\right)},$$

(16)

where W_O is the water rights of other agriculture (m³); R_Ok is the production of other agriculture k; M_Ok is the water quota of other agriculture.

(6)

The constraints of water rights of general industry:

$$W_I\ge {\displaystyle \sum \left(R_{Ik}\times M_{Ik}\right)},$$

(17)

where W_I is the water rights of general industry (m³); R_Ik is the production of general industry k; M_Ik is the water quota of general industry.

(7)

The constraints of total water rights:

$$W_L+W_E+W_N+W_F+W_O+W_I\le WR,$$

(18)

where WR is the total water rights in this city.

(8)

The method to solve model

The MATLAB software and particle swarm optimization algorithm are used to solve the water rights allocation model in this study.

3. Results

According to the water rights allocation model proposed above, Yinchuan in 2019 is taken as an example to calculate the water rights allocation of coordinated development on water–ecology–energy–food. Among the data required for calculation, the water resources data are from Ningxia Water Resources Bulletin (2013–2019) [29,30,31,32,33,34,35], and social and economic data are from Yinchuan Statistical Yearbook (2014–2020) [36,37,38,39,40,41,42]. The total amount data of water rights allocation in Yinchuan comes from the Yellow River Institute of Hydraulic Research. We put the data into Equations (1) to (18), using MATLAB software to compile the particle swarm optimization algorithm for iterative solution. The result of water rights allocation for the coordinated development on water–ecology–energy–food in Yinchuan is obtained, as shown in

Table 2. Water rights allocation scheme of the coordinated development of water–ecology–energy–food in Yinchuan.

Industry	Water Rights of Life WL	Water Rights of Ecology WE	Water Rights of Energy Industry WN	Water Rights of Food Planting WF	Water Rights of Other Agriculture WO	Water Rights of General Industry WI	Total
Water rights (×108 m3)	0.99	1.77	1.80	4.06	5.20	0.88	14.70

:

4. Discussion

4.1. Results Analysis of Water Resources Value in Various Industries

(1)

Comparison of the water resources value in various industries under current water rights and allocated water rights. In the efficiency objective of city-industry water rights allocation model, the emergy method is used to calculate the value of water resources in various industries in this paper. The comparison of water resources value in various industries before and after water rights allocation is shown in Figure 2:

It can be seen from Figure 2, after the allocation of water rights for the coordinated development on water- ecology-energy-food, the value of water resources in various industries in Yinchuan has changed. The water resources value in the living system it increased by 2.10 × 10⁸ CNY, in the ecosystem it increased by 0.22 × 10⁸ CNY, in the energy industry system it decreased by 0.70 × 10⁸ CNY, in the food planting system it decreased by 0.32 × 10⁸ CNY, it increased by 0.14 × 10⁸ CNY in other agricultural systems, and it increased by 0.86 × 10⁸ CNY in general industrial systems. The total water resources value increased by 2.31 × 10⁸ CNY compared with before allocation. It can be seen that after the allocation of water rights, the overall value of water resources in Yinchuan city has increased, and the efficiency of water resources utilization has improved. When Li et al. [43] optimized the regional water use structure based on water resource vulnerability, they also took the industrial water resource value as an important influencing factor to allocate water resources. In this paper, emergy method is used to quantify the water resources value in various industries, which is conducive to obtain the objective and reliable allocated results.

(2)

Comparison of the value of water resources per cubic meter in various industries. According to the calculation of the value of water resources and the allocation results of water rights in various industries, the value of water resources per cubic meter in Yinchuan city can be obtained. The value of water resources per cubic meter of the living system is the highest, reaching 15.54 CNY/m³, followed by that of the energy industry system, reaching 10.28 CNY/m³, and that of the food production system is the lowest, only 0.67 CNY/m³. The value of water resources per cubic meter in the ecosystem is 2.05 CNY/m³, that of other agricultural systems is 4.94 CNY/m³, and that of general industrial systems is 5.37 CNY/m³. Wang Yu et al. [44] used the emergy method to calculate the value of water resources per cubic meter of the four sectors (life, industry, extra-river ecology, and agriculture) in nine provinces and autonomous regions in the Yellow River Basin. They also obtained the result that the value of water resources per cubic meter of life sector is the largest and that of the agriculture sector is the smallest. Li et al. [43] also suggested that the value of water resources per cubic meter of agriculture is minimal. The food planting industry is faced with the problem of low water efficiency, and it is a trend that accelerates the development of regional water-saving agricultural engineering renovation.

4.2. Results Analysis of Coordinated Development Index G

Through the optimal allocation of the right to use water resources of various industries in Yinchuan in 2019, the change of water rights of various industries will directly affect the values of some comprehensive evaluation indicators. It will thus change the size of the coordinated development index on water–ecology–energy–food. The trend and comparative analysis of that in Yinchuan from 2013 to 2019 under the condition of current water rights and allocated water rights are shown in Figure 3:

As can be seen from Figure 3, in terms of the extended development trend of the water–ecology–energy–food coordinated development index, except that the current water rights declined in 2017, the current indexes and the allocated indexes basically showed an upward trend from 2013 to 2018. Both dropped significantly in 2019 compared to the previous year. Through the analysis of comprehensive evaluation indicators data, it is found that natural annual precipitation (B₁) decreased significantly in Yinchuan in 2019, and the energy exploitation and food crop yield was decreased. As the result, the per capita water resources (A₁), energy self-sufficiency rate (C₃) and food self-sufficiency rate (D₄) and other positive indicators decreased significantly, which has an impact on the coordinated development index in this year. The coordinated development index under the current water rights condition has a slight decline in 2017, which is due to the obvious decline of annual precipitation (B₁) in this year compared with 2016.

It can also be seen from Figure 3 that in 2014 and 2016, the coordinated development index under current water rights is slightly larger than that under allocated water rights, which is mainly caused by the changing trend of the proportion of water rights in food planting (AD₁). The proportion of water rights of food planting (AD₁) peaked in 2014 and 2016, at 52.36% and 51.54%. Compared with the situation of current water rights in 2019, it is 30.90%, and the proportion of water rights of food planting (AD₁) under allocated water rights is even smaller, only 27.62%. Under the condition of allocated water rights, the proportion of water rights of food planting (AD₁) is more discrete than the current water rights, which leads to the decrease of the coordinated development index of water–ecology–energy–food.

From 2013 to 2016, the coordinated development index under the condition of allocated water rights was basically equal to that under the condition of current water rights. From 2017 to 2019, the coordinated development index under the condition of allocated water rights was significantly higher than that under the condition of current water rights. It can be shown that the regional water–ecology–energy–food coordinated development state obtained by water rights allocation in this paper is superior to the current situation. The water rights allocation model established in this paper can provide reference and help to promote the coordinated development of regional water–ecology–energy–food.

4.3. Results Analysis of Water Rights Allocation

A comparative analysis is made between the current water rights of various industries in Yinchuan in 2019 and the allocated water rights in various industries based on the coordinated development of water–ecology–energy–food in this paper, as shown in Figure 4.

As can be seen from Figure 4, the allocated water rights of life in Yinchuan increased by 1.07%, the allocated water rights of ecology increased by 1.85%, the allocated water rights of energy industry decreased by 1.09%, that of food planting decreased by 3.27%, that of other agriculture increased by 0.83%, and general industry increased by 0.65% compared with the current water rights. Water rights of life and ecology have increased, while agricultural water rights have decreased and industrial water rights have little change, which is consistent with the optimization trend of water resources in the Yellow River Basin proposed by Xia et al. [45]. In addition, according to Yinchuan’s future economic and social development focus, urban planning and industrial and agricultural construction characteristics, the water rights allocation scheme based on coordinated development of water–ecology–energy–food in this paper is reasonable and sustainable, which can provide some reference for the reasonable allocation of regional water rights.

5. Conclusions

In this paper, the water resource is taken as the object of control, and a municipal-industry water rights allocation model for the coordinated development of water–ecology–energy–food is established. The fairness objective of the model is established by satisfaction function, the efficiency objective is established by the emergy method, and the coordinated development objective is calculated by comprehensive evaluation method. We calculate the water security for each industry as constraints of the water right allocation model. The conclusions are as follows:

(1)

Water, ecology, energy, and food crises are major challenges to current global development. These four resources are intertwined and affect each other, and can therefore not be discussed individually. Therefore, starting from their coordinated development, they can better solve the crisis. The quantitative method of water–ecology–energy–food coordinated development constructed in this study, and the quantitative calculation results of Yinchuan coordinated development, can provide management reference for management departments;

(2)

In this paper, the emergy method is used to achieve a unified and objective quantitative calculation of the value of water resources in various industries, which makes the result of water rights allocation more reliable. At the same time, it also has certain fairness significance. The Emergy method can realize the unified quantification of the economic, social, and ecological environmental value of water resources. The value of water resources calculated by this method is more scientific and reasonable;

(3)

The water rights allocation model of regional water–ecology–energy–food coordinated development established in this paper has ensured the water security of ecological restoration, key energy industries, and food planting. It can take reference and help for effectively solving the contradiction between the supply and demand of regional water resources, promoting the harmony of water use in various industries. It can also promote the sustainable development of economy, society, and ecology.

There are still some shortcomings in this paper: It is difficult to completely distinguish the cross industries when dividing the industries, and it is also difficult to make comprehensive statistics of all water use units in the industry. Further research is needed in the future.