Study on the Relationship between Water Resources Utilization and Economic Growth in Tarim River basin from the Perspective of Water Footprint

Abstract

Taking the Tarim River basin as the research object, the water footprint was calculated based on the water footprint theory based on the relevant data from 2008 to 2019, and the water resource evaluation system was constructed to analyze the water footprint and water resource utilization of the Tarim River basin from three levels of structure, benefit, and ecology. Based on the water footprint theory, the annual water footprint and GDP of Tarim River basin were used to construct the Tapio decoupling model, and the decoupling type between water resources utilization and economic growth was obtained. The relationship between water resource utilization and economic growth in Tarim River was analyzed by combining the decoupling type evaluation and water footprint evaluation. The internal benefit is poor, and the external benefit is good; The degree of water resource shortage is on the rise, and the self-sufficiency rate of water resources is large. On the whole, the decoupling strength increases gradually. Decoupling strength has obvious industrial influence characteristics. Based on the above research conclusions, the sustainable economic and ecological development of the Tarim River basin can be realized from two aspects: reducing water footprint and strengthening decoupling intensity.

1. Introduction

At present, the problem of water resources has increasingly restricted the development of “three types” of agriculture in the Tarim River basin. As one of the most important oasis agricultural areas in China, Tarim River basin is one of the aridest regions in China and even in the world, with the largest gap between water supply and demand and the most vulnerable ecology, as well as the highest agricultural water consumption ratio. The extreme lack of water resources, the disordered expansion of agricultural water, and the extremely low efficiency of water use greatly occupy the ecological water and make the agricultural ecosystem continue to deteriorate.

Tarim River is the mother river of all ethnic groups in Southern Xinjiang [1]. Scholarly research on water resources in Tarim River basin is mainly carried out from the perspectives of utilization [2,3], change trend [4], utilization and ecological conservation [5], ecological compensation [6], carrying capacity [7,8,9], the economic effect of allocation and utilization [10], water price adjustment [11], supervision [12] and research progress [1]. There are few studies on the coordination of water resource utilization and economic development in the Tarim River basin. Li and Yang predicted the direct benefits of water resource utilization and the cost of surface runoff restoration in the lower reaches of the Tarim River basin based on the apportion method [3]. Chen et al. pointed out the existing problems of water system connectivity of the Tarim River basin through field investigation and sample site investigation, and put forward corresponding suggestions from management, scientific overall planning, monitoring, and scheduling control [13]. The above research on the Tarim River basin mainly focuses on the physical water, ignoring the consumption of virtual water, which makes the water resource loss in the Tarim River basin not fully and truly reflected.

Zhang studied the evolutionary process and driving factors of the Tarim River basin by using the “pendulum model” based on the coupled evolution theory [14]. Qiao and Gao used the Vehmast decoupling model to study the relationship between water resource utilization and economic coordinated development in Xinjiang from the perspective of water footprint and put forward corresponding suggestions [15]. Xie et al. studied the relationship between agricultural water resources utilization and agricultural economic growth in various basins of Xinjiang through the Tapio model and LMDI decomposition model and pointed out that reducing water resources consumed per unit of agricultural output value is an effective measure to improve the utilization rate of agricultural water resources in Xinjiang [16]. Chen used the Tapio model to analyze the decoupling of Kezhou, Kashgar, and Hotan and found that strong and weak decoupling appeared alternately, and the overall trend gradually turned better [17]. Although the above studies on the relationship between water resource utilization and economic growth in Xinjiang can provide some reference for water resources management and economic development in The Tarim River basin, there are few specific explanations for the relationship changes from the perspective of policy.

Domestic scholars have conducted many studies on the relationship between water resources utilization and economic growth, mainly using the VAR model [18,19,20,21], cointegration analysis [22,23], coupling coordination model [24], decoupling model [25,26,27,28], etc., to study various regions in China. The decoupling model has been used by many people and achieved corresponding success. However, there are relatively few studies on the Tarim River basin, an arid agricultural area that does not produce runoff [29], and their direct reference value to the Tarim River basin is relatively small.

Tarim River basin in Xinjiang Tianshan geosyncline and Tarim platform between the piedmont sag zone [29], earth across five (state) (Aksu area, Bayingolin Mongolian Autonomous Prefecture, Kashgar Prefecture, and Kizilsu Kirghiz Autonomous Prefecture), Four units of Xinjiang Production and Construction Corps (1st, 2nd, 3rd, and 14th Divisions). It is the basin with the largest number of inter-local (prefectures, counties, and cities) in Xinjiang [30]. As the mother river [31] of people of all ethnic groups in Southern Xinjiang, the Tarim River is rich in petroleum, natural gas, light, heat, and biological resources, and is an important strategic reserve base of energy and resources for the sustainable development of China’s economy and society in the 21st century [32]. The Tarim River basin is high in the west and low in the east and high in the north and low in the south [30], with a radiation area of $102\times {10}^4{\mathrm{km}}^2$ [3] and the mainstream length of 1321 km [13], but no current is produced by itself [29]. Before 1949, nine rivers and the mainstream Tarim River maintained a surface water supply. At present, only the Aksu River, Hetian River, Yeerqiang River, and Kaidu-Kongque River can supply water resources for the Tarim River basin [30], among which the Kaidu-Kongque River adopts artificial water transport [32], thus forming the pattern of “four sources and one trunk”. The Tarim River basin is inhabited by Uyghur, Han, Kazak and Hui, and other people, among which Uyghur account for the highest proportion. According to the 2019 Statistical Yearbook of Xinjiang, Xinjiang’s GDP in 2018 was 1219.908 billion yuan, and that of the Tarim River basin amounted to 3969.295 billion Yuan, accounting for 32.54% of the total. Secondary industry and tertiary industry accounted for 37.74% and 37.17% of the annual GDP of the Tarim River basin in 2018, respectively.

The research area has extremely special practical significance in China and even the world. From China, in a continental river basin in the Tarim River basin is China’s largest, is a rare collection of agricultural droughts, degeneration of the ecological fragile district coupling specific area, major poverty-stricken areas and ethnic minority areas, is China’s largest production base of high-quality cotton, and national ecological management and strengthen poverty engines and achieve the rural revitalization of one of the key battlegrounds. The Tarim River basin is one of the aridest regions in China and even in the world, with the largest gap between water supply and demand and the most vulnerable ecology. It is also one of the regions with the highest agricultural water consumption ratio and lowest water resource utilization efficiency. The Tarim River basin is located at the edge of the Taklimakan Desert, the second largest desert in the world. The climate is arid, and the vegetation is sparse, and the ecological environment is fragile. The agricultural development mainly depends on diversion irrigation, with an irrigation area of nearly 1.4 million hectares, which is a typical “oasis economy”. Water is the lifeblood not only of agriculture, but of the entire national economy and ecosystem. In 2015, the No. 1 document of the Central Committee of the People’s Republic of China proposed strengthening agricultural ecological governance, vigorously promoting the development of agricultural circular economy, major ecological forestry projects, and promoting ecological protection and restoration in the Beijing-Tianjin-Hebei Region, the Silk Road Economic Belt and the Yangtze River Economic Belt. Therefore, under the severe constraints of water resources, how to rationally allocate limited water resources and realize the coordination of “production, life and ecology” is a major scientific issue for this region. To solve this problem, we must have a deep understanding of the water footprint of this region, formulate a scientific and reasonable water resources management policy, realize the sustainable development of ecology and economy in the Tarim River basin, and accelerate the realization of the second Centennial Goal of China. This is the fundamental starting point of this study.

The structure of this paper is as follows: (1) Data sources and water footprint model and Tapio decoupling model are introduced. (2) Analyze the water footprint from the aspects of water footprint composition and structural change; (3) The efficiency, scarcity, and self-sufficiency rate were evaluated by the water footprint evaluation system. (4) Calculate the decoupling coefficient and judge the type; (5) Interpret the relationship between the two from the perspective of policy; (6) Summarize the conclusions and put forward suggestions.

2. Research Methods and Data Sources

2.1. Data Sources

Due to geographical factors, the first Division and Aksu area, the second Division and Bazhou, and the third Division and Kashi are respectively classified into the Aksu area, Bazhou area, and Kashi area for research. The data on water supply and water consumption (Including Xinjiang Production and Construction Corps) are from the statistical Yearbook of Xinjiang from 2009 to 2020, which lacks the data on water supply and water consumption of the Tarim River basin in 2012. According to the water supply and water consumption in the adjacent years and the published total water resources in 2012, the water supply and water consumption in the Tarim River basin in 2012 are estimated by calculating the average value, and the other few missing data are estimated in the same way. The research data of total population, GDP and output of various agricultural products at the end of each year in Tarim River basin are obtained from the statistical yearbook of Xinjiang, the Xinjiang production and construction corps statistical yearbook, Aksu statistical yearbook and general yearbook, the general statistical yearbook grams of Kizilsu Kirghiz yearbook and the regional people’s government of the network, the missing data is estimated by the average of adjacent years or the average of relevant data proportion.

According to the research time and region of the unit virtual water quantity of agricultural products, the unit virtual water quantity of plant products comes from the research results of Sun [33], and the unit virtual water quantity of animal products is based on the research results of Mekonnen in China in 2010 [34], among which the unit virtual water quantity of aquatic products adopts the data of Liu [35]. The virtual water quantity per unit of vegetables was obtained by Wang [36], for details, see

Table 1. Virtual water content of main products and source Unit: m³/kg.

Data Sources	Product Name	Virtual Water Content per Unit of Product
Reference [33]	corn	0.730
	wheat	1.050
	rice	1.210
	potato	0.880
	cotton	3.810
	oil	2.430
	Sugar beet	0.100
Reference [36]	vegetables	0.190
Reference [33]	fruit	0.870
Reference [34]	pork	5.455
	beef	13.290
	mutton	5.799
	poultry	3.117
	eggs	2.428
	milk	1.072
Reference [35]	Aquatic products	5.000

:

2.2. Water Footprint Calculation Model

“Virtual water” refers to the total amount of water consumed by a product (service) in its design, production, processing, transportation, and sale. On this basis, in 2003, Chapagain and Hoekstra et al. proposed the theory of water footprint [37], which can be defined as the virtual water amount of all products (services) consumed by a known number of people in a certain area (region) during their normal life in a certain period.

The water footprint calculation method proposed by Wu et al., is only applicable to the water footprint of crops [38], and not applicable to the calculation of the overall water footprint of Tarim River basin, while the water footprint method proposed by Chapagain and Hoekstra is applicable to the total regional water footprint, which is convenient for analyzing the relationship between regional water footprint and regional economic development. Therefore, Chapagain and Hoekstra proposed the water footprint theory and its accounting method [37]. The symbols used in the calculation model are shown in

Table 2. Symbol description of water footprint model [26].

Abbreviations and Symbols	Item Name	Contains the Meaning
$WFP$	Total water footprint	The virtual amount of water consumed by a given number of people in an area in the normal course of their lives
$IWFP$	Internal water footprint	The amount of water consumed by goods or services produced within the region and used within the region
$EWFP$	External water footprint	The amount of water consumed within the region for goods or services produced or provided outside the region
$AWU$	Agricultural virtual water quantity	Actual water consumption during agricultural production in the region
$IWU$	Industrial virtual water quantity	Actual water consumption in the industrial process of the area
$DWU$	Living virtual water quantity	The actual water consumption of residents in the area
$EWU$	Ecological virtual water quantity	The actual water consumption of the ecological environment in the region
$VWU$	Virtual outlet water quantity	The virtual amount of water produced within the region and exported to products (services) outside the region
$VWI$	Imported virtual water quantity	The virtual amount of water produced outside the region and imported into the region for products (services)
$VWE$	Import re-export	The virtual amount of water for products (services) produced outside the region, imported into the region, and then exported

, and the model formula is as follows:

The water footprint of a certain region is divided into two parts, one is the internal water footprint, and the other is the external water footprint [26], namely:

$$WFP=IWFP+EWFP$$

(1)

Internal water footprint is the sum of agricultural virtual water, industrial virtual water, domestic virtual water, and ecological virtual water minus export virtual water, namely:

$$IWFP=AWU+IWU+DWU+EWU-VWU$$

(2)

The external water footprint is the difference between imported virtual water quantity and imported and re-exported virtual water quantity, namely:

$$EWFP=VWI-VWE$$

(3)

2.3. Calculation Methods of Different Types of Water Footprint

2.3.1. Virtual Water Amount for Agricultural Production

AWU (Agricultural virtual water quantity) is represented by the virtual water consumption of agricultural production and services in the region, and is calculated as follows [26]:

$$Virtual water amount of agricultural production=virtual water content per unit product\ast output$$

(4)

The virtual water amount of agricultural production includes the virtual water amount of production or service in the process of planting crop products and breeding animal products [39]. According to the characteristics of the agricultural structure in the Tarim River basin and the availability of virtual water amount per unit product. Eight major crop products (corn, wheat, rice, potato, cotton, oil, sugar beet, vegetable, and fruit) and seven major animal products (poultry, beef, milk, pork, aquatic products, mutton, and poultry eggs) were selected to calculate the agricultural virtual water amount.

2.3.2. Industrial Virtual Water Quantity, Domestic Virtual Water Quantity, Ecological Virtual Water Quantity, Import, and Re-Export Virtual Water Quantity

IWU (industrial virtual water quantity), DWU (residential virtual water quantity), and EWU (ecological virtual water quantity) are directly represented by physical water quantity due to the lack of a more scientific accounting method, that is, water consumption of primary industry, residential living water consumption and ecological water consumption provided in Xinjiang Statistical Yearbook. As VWE (import and re-export virtual water volume) is difficult to calculate, and there is no reference data, it is ignored.

2.3.3. Virtual Water Quantity Exported and Imported

VWU (export virtual water volume) and VWI (import virtual water volume) are collectively referred to as virtual water trade volume. It is difficult to calculate the specific virtual water volume due to export category and quantity, so previous scholars’ accounting methods [40,41] are referred to, namely:

Export value Total production water consumption

$$VWU=\frac{Export value}{GDP}\times Total production water consumption$$

(5)

$$VWI=\frac{Import value}{GDP}\times Total production water consumption$$

(6)

2.4. Actual Calculation Formula of Regional Water Footprint

As virtual water volume (VWE) of import and re-export is difficult to calculate, the quantity of such products in the study area is very small and there is no reliable statistical data for reference, so it is ignored. That is, it is considered zero. According to Equations (1)–(3), the actual water footprint can be calculated by:

$$WFP=AWU+IWU+DWU+EWU-VWU+VWE$$

(7)

2.5. Water Footprint Evaluation Index

In 2011, Qi et al. constructed the water footprint evaluation system of water footprint benefit, structure, sustainable performance, and ecological security index, based on the water footprint theory [42]. Since the evaluation index constructed by Qi et al., could evaluate the regional water footprint from three dimensions, the water footprint evaluation model proposed by Qi Rui et al., was adopted. Based on the research content of this paper, Population density of ten thousand tons of water footprint, water footprint economic value, the density of water footprint land, net trade water footprint and water footprint contribution rate, water footprint value exchange rate, the WS (water shortage index), WFPR (water footprint growth index), WAR (available water growth index), WSI sustainable index (water), a total of eight evaluation index, To reveal the internal and external benefits, ecological security and sustainability of water resources in Tarim River basin.

2.5.1. Evaluation Index of Internal Benefits of Water Footprint

• Population density of water footprint in ten thousand tons

Population density of water footprint per 10,000 tons refers to the normal living population of a region per 10,000 tons of water footprint. It is the percentage of total population (TP) and total water footprint (WFP) at the end of the year in a region. The value of population density of ten thousand tons of water footprint is positively correlated with the effective force of water resources in the region, and the larger the value is, the more population can be maintained in the region, the more conducive to the sustainable economic development of the region. The calculation formula is as follows:

$$Ten thousand tons of water footprint population density=\frac{TP}{WFP}$$

(8)

2.

Economic benefits of water footprint

Water footprint economic benefit refers to the economic benefit created by each unit of water footprint consumption in a certain region, which is the percentage of annual GDP and total water footprint of the region (WFP). The economic benefit value of water footprint is positively correlated with the economic benefit created after water footprint consumption. The larger the value is, the higher the utilization level of water resources in this region will be. In other words, under the same economic benefits, the consumption of water footprint in areas with high economic benefits is lower. The calculation formula is as follows:

$$Water footprint economic benefit value=\frac{GDP}{WFP}$$

(9)

3.

Water footprint land density

Water footprint Land density refers to the water consumption per unit area of A region, which can be obtained by dividing the total water footprint (WFP) by area (A). The value of land density of water footprint is positively correlated with the amount of water consumed in this area. The larger the value is, the higher the amount of water consumed per unit area in this area is. The calculation formula is as follows:

$$Water footprint land density=\frac{WFP}{A}$$

(10)

2.5.2. Evaluation Index of External Benefits of Water Footprint

1.

Water footprint net trade value

Net trade value of water footprint refers to the virtual water quantity difference between import and export in the process of external water footprint trade in a certain region at a certain period, which can be obtained by subtracting the virtual water quantity exported (VWU) from the virtual water quantity imported (VWI) of the region. This can be reflected in the region’s position, role, and status quo of its water resources policy in the trade process. If the virtual water volume exported (VWU) is greater than the virtual water volume imported (VWI), the water footprint trade value is positive, indicating that the region is the source of water resources when conducting water footprint trade with the outside world, detrimental to the sustainable development of the local economy. Otherwise, if it is negative, it is the input place of water resources, conducive to the sustainable development of the local economy. The calculation formula is as follows:

$$Water footprint net trade value=VWU-EWFP$$

(11)

2.

Water footprint contribution rate

Water footprint net trade value divided by the area of the amount of water available (WA) can get water footprint contribution rate, and it reflects in the water footprint trade with the outside world, the area for the rest of the pressure water resources situation of the strength of the relief, if the ratio is larger, the water pressure in other areas of the stronger the relief, the weaker conversely. The calculation formula is as follows:

$$Water footprint contribution rate=\frac{VWU-EWFP}{WA}$$

(12)

3.

Water footprint value conversion rate

The water footprint value exchange contribution rate refers to the monetary value of the water footprint of a unit exported by a region in the process of foreign trade. The water footprint value exchange contribution rate can be obtained by dividing the import trade value of the water footprint by the export trade value of the water footprint. The higher the value is, the more beneficial the exported products are to the sustainable development of the local economy and ecology. The calculation formula is as follows:

$$Water footprint value exchange contribution rate=\frac{\frac{Import value}{EWFP}}{\frac{Export value}{VWU}}$$

(13)

2.5.3. Water Footprint Scarcity Index

The water footprint Scarcity index (WS) refers to the water resource stress degree of a certain region in a certain period. The water footprint scarcity index can be obtained by dividing the total amount of regional water footprint (WFP) by the area (WA). The larger the index is, the more water resources are scarce. If it exceeds 100%, it indicates that the demand for water in the production, manufacturing of products and services, and living conditions in the region is greater than the number of water resources available in the region at the same time, and the region is in an extreme water shortage state. The calculation formula is as follows:

$$WS=\frac{WFP}{WA}\times 100\%$$

(14)

2.5.4. Self-Sufficiency Rate of Water Resources

Water resource self-sufficiency rate (WSS) refers to the share of local water resources in water resources consumed by people in production and living in a region. The percentage of IWFP and WFP in a region is the water resource self-sufficiency rate (WSS). The higher the ratio is, the greater the dependence of local production and domestic water on local water resources, and vice versa. The calculation formula is as follows:

$$WSS=\frac{IWFP}{WFP}$$

(15)

2.6. Tapio Decoupling Model

“Decoupling” has been applied to various fields of research since it was proposed in the 1960s. In the 1990s, OECD began to gradually apply decoupling to the study of the relationship between local resources and their economic development [43].

The decoupling model divides the relationship between regional economic development and the use of water resources in a certain period into two opposite relationships: coupling and decoupling. Decoupling refers to the increase of the overall economy of various industries in the region, the use of water resources in the region, and the pressure on the ecology in the region gradually decreasing. On the contrary, if it increases, it is coupling [44].

After the 21st century, Chinese scholars gradually began to use the decoupling model to evaluate the relationship between water resources and social and economic development in different parts of China. The decoupling models used by Domestic scholars mainly include the Vehmast decoupling index (comprehensive analysis method) [27,43,45,46], Tapio elasticity index [15,47,48,49], IGT decoupling [50], OCED decoupling factor, and EKC curve [51]. Among them, the IGT decoupling model and OCED model are not adopted because the judgment results are relatively general, and only undecoupling, relative decoupling, and absolute decoupling can be determined by the results. Because the EKC curve has a large demand for data [51], it is not adopted based on data availability. Vehmast decoupling index (comprehensive analysis method) is relatively easy to operate, and the discriminant results are consistent with the definition and easy to understand. However, it fails to pay attention to the differences among various levels of decoupling and fails to consider the critical state [51], which has certain defects. The Tapio elasticity index obtained after improvement based on the Vehmast decoupling index just makes up for the defect of the Vehmast decoupling index. Therefore, the Tapio elasticity index collects advantages such as easy discrimination, accurate discrimination, comprehensive, scientific, and low data demand [51], so this paper adopts the Tapio elasticity index.

The calculation model of the Tapio elasticity index is as follows [47]:

$$e=\frac{\%\Delta WFP}{\%\Delta GDP}$$

(16)

In Formula (15), e is the Tapio elasticity index, %∆GDP represents the GDP growth rate at the end of the year t, %∆WFP represents the change rate of water footprint at the end of the year t.

$$\%\Delta GDP=\frac{GD{P}_t-GD{P}_{t-1}}{GD{P}_{t-1}}$$

(17)

In Formula (16) GDP_t represents the gross product at the end of the year t, and GDP_t−1 represents the gross product at the end of the year t − 1.

$$\%\Delta WFP=\frac{WF{P}_t-WF{P}_{t-1}}{WF{P}_{t-1}}$$

(18)

In Formula (17), WFP_t represents the total amount of change in water footprint at the end of year t, and WFP_t−1 represents the total amount of change in water footprint at the end of year t−1.

Tapio elastic model divides decoupling into three categories: decoupling (A, B, C), negative decoupling (D, E, F), and connection (G, H). Strong decoupling (A) indicates that the relationship between water resource utilization and the economic development of the region in the period is in the best state, which not only ensures social and economic growth, but also reduces the water consumption for production or service. In contrast, strong negative decoupling (D) is the worst state, in which the social economy declines while the consumption of water resources increases and the sustainable development of water resources and social economy cannot be realized. Weak decoupling state (B) indicates that both the economy and water consumption grow at the same time, but the consumption of water resources is faster than the economic growth. In contrast, expansionary negative decoupling (F) means that economic growth is faster than water consumption. Weak negative decoupling (E) indicates that the consumption of water resources decreases at the same time as the economic recession, and the water resources decrease faster than during the economic recession. The opposite is recessionary decoupling (C), in which the economy declines faster than water resources decline. Expansionary coupling (G) indicates that the rate of economic growth is basically the same as the rate of water consumption growth, while recessionary coupling (H) indicates that the rate of economic decline is basically the same as the rate of water consumption reduction.

Tapio decoupling status judgment criteria [47] As shown in Figure 1:

3. Calculation Results and Analysis

3.1. Water Footprint Analysis

3.1.1. Comparison of Water Footprints in Different Regions

According to the calculation of the water footprint model, the average growth rate of water footprint was 7.27% from 2008 to 2019. The water footprint of the Tarim River basin fluctuated greatly from 2008 to 2016 and showed a trend of decline from 2016 to 2018. The period from 2011 to 2015 was in the 12th Five-Year Plan period, during which the development of characteristic and advantageous industries was advocated. During this period, the virtual water amount of characteristic agricultural products in the Tarim River basin gradually increased. Due to the policy lag, the “moderate development” proposed in the agricultural modernization Plan (2016–2020) failed to play a significant role in 2016. It may be one of the main reasons for the maximum water footprint of 36.702 billion m³ in 2016. One possible explanation for the negative growth of water footprint in The Tarim River basin from 2016 to 2018 is that the 13th Five-Year Plan, the National Agricultural Modernization Plan (2016–2020), and the implementation of the river chief system in Xinjiang Autonomous Region have taken measures to save water resources from various aspects.

As can be seen from

Table 3. Water footprint of Tarim River basin from 2008 to 2019 table locations. Unit: hundred million m³.

Year	Water Footprint (WFP)
	Aksu	Bazhou	Kashgar	Kizilsu Kirghiz	Hetian	Tarim River basin
2008	64.74	36.89	24.76	1.89	21.01	149.28
2009	73.70	42.79	65.22	6.13	21.45	209.28
2010	74.49	45.22	69.59	8.28	20.17	217.75
2011	82.95	44.73	79.88	7.13	20.90	235.59
2012	87.48	48.86	109.19	6.31	22.50	274.34
2013	92.39	51.82	94.12	5.66	23.36	267.35
2014	111.48	58.41	110.18	5.08	22.98	308.13
2015	120.74	59.08	120.50	8.04	22.46	330.82
2016	128.60	70.03	100.66	8.15	59.58	367.02
2017	125.94	63.50	90.19	7.08	25.79	312.49
2018	108.05	52.52	88.81	8.30	25.99	283.67
2019	109.98	50.82	100.48	7.54	26.72	295.54
Mean	98.38	52.05	87.80	6.63	26.07	270.94

Data source: According to the statistical yearbook of Xinjiang.

, the Aksu area has the highest average water footprint of 98.38 hundred million m³, followed by the Kashgar area. As can be seen from the Map of China, the land area of the Aksu area is slightly smaller than that of the Kashgar area, ranking in the middle among the five areas of the Tarim River basin. The factors influencing the average water footprint of the Aksu area are export virtual water amount, domestic virtual water amount, and secondary industrial virtual water amount. As can be seen from the calculation results, the average total population in the Aksu area at the end of the year is 61.35% of the Kashgar area, and the virtual living water in the Aksu area is 61.26% of the Kashgar area. The average GDP in the Aksu area is 1.89 × 10⁷ thousand yuan higher than the Kashgar area, about 1.27 times of the Kashgar area. Moreover, the average agricultural virtual water content, the virtual water content of the tertiary industry, and the virtual water content of import and export in the Aksu area are all lower than that in the Kashgar area, and only the virtual water content of the secondary industry is 4.09 × 10⁷ m³ higher than Kashgar area, which is about 1.51 times of Kashgar area, indicating that the increase of water consumption in the secondary industry is beneficial to economic growth.

As can be seen from the calculation results, the average GDP and area of Bazhou are both the highest, and the average GDP of Aksu ranks second. As can be seen from Table 3, the water footprint of Bazhou is much lower than that of Aksu, indicating to some extent that economic growth in Bazhou is less dependent on water resources and the utilization of water resources is relatively reasonable. The agricultural virtual water amount in Aksu is 203.53% of that in Bazhou, indicating that Aksu, which takes agriculture as its main economic source, is highly dependent on water resources. The export virtual water volume of Aksu is much higher than that of Bazhou, about 4.1 times that of Bazhou. Most of its export products are products with low added value and high virtual water content, indicating that the import and export economic growth of Aksu is highly dependent on water resources. The area of Bazhou is dominated by the petroleum and chemical industry and tourism. The virtual water amount of the tertiary industry is 182.96% of that of Aksu, and the virtual water amount of ecological water is 469.98%. The above shows that to a certain extent, the tertiary industry water consumption and ecological water consumption have a greater promoting effect on the economy than the increase in agricultural virtual water consumption.

As can be seen from Table 3, the average water footprint of Kashgar is higher than that of Bazhou, while the average GDP and area of Bazhou are both higher than Kashgar. As can be seen from the calculation results, the average total population at the end of the year in Bazhou is only 34.14% of Kashgar, and the average living virtual water in Bazhou is relatively small. It may be because the agricultural products in Kashgar are one of its main economic sources, and its virtual agricultural water consumption is 226.19% of that in Bazhou. Agricultural products consume a lot of water but bring relatively small economic benefits. Although the average virtual water volume exported from Kashgar is 3368.62% of that from Bazhou, the export products from Kashgar are mainly light industrial products, agricultural products, and daily products with relatively low added value and large virtual water volume, which brings relatively limited economic benefits. The petrochemical industry in Bazhou is relatively developed, and the average virtual water volume of the secondary industry is the highest, which brings relatively large economic benefits. The above shows that, to a certain extent, the increase in water resource utilization in the secondary industry has a greater promoting effect on the economy than the increase of agricultural virtual water resources on GDP.

3.1.2. Composition of Water Footprint

Agriculture is the main economic source in The Tarim River basin, and it can be seen from

Table 4. Virtual water structure of Tarim River basin from 2008 to 2019. (Unit: hundred million m³).

Year	Agriculture	The Second Industry	The Third Industry	Life	Ecology	Export	Import	The Total WFP	WFP per Capita m3
2008	207.42	2.83	0.66	2.60	6.04	72.11	2.50	149.28	1435.06
2009	226.65	2.62	0.52	3.09	5.83	29.82	0.90	209.28	1965.38
2010	230.90	3.05	0.48	2.42	4.44	23.99	0.93	217.75	1990.03
2011	247.40	3.44	0.51	3.10	3.03	22.18	0.79	235.59	2105.59
2012	285.91	4.02	0.67	3.38	2.88	22.76	0.91	274.34	2447.24
2013	297.81	4.39	0.68	3.78	1.93	41.29	0.72	267.35	2316.96
2014	334.58	4.02	1.03	3.44	1.63	36.31	0.77	308.13	2568.90
2015	343.68	3.75	1.02	3.77	1.53	23.34	1.44	330.82	2739.03
2016	391.23	3.75	1.02	3.77	1.53	35.09	1.83	367.02	3042.05
2017	331.90	4.99	1.00	4.95	2.81	34.34	2.18	312.49	2518.74
2018	280.11	4.09	0.44	4.46	12.38	17.87	0.50	283.67	2320.43
2019	303.24	4.50	0.75	4.57	5.83	23.29	0.69	295.54	2340.41

Data source: According to the statistical yearbook of Xinjiang.

that agriculture consumes the most water in the Tarim River basin. The agricultural virtual water volume increased year by year from 2008 to 2016, possibly because the 12th Five-Year Plan advocated the development of characteristic industries. Due to the lag of the policy, the agricultural virtual water reached the maximum value of 39.123 billion m³ in 2016. Agriculture of virtual water in 2016–2019 a declining trend, may be one explanation for: the Tarim River basin in Xinjiang Uygur autonomous region water resources management ordinance “national agricultural modernization (2016–2020)”, the river chief system has been implemented in Xinjiang Autonomous Region and effective management measures have been taken in the “13th Five-Year Plan” of Xinjiang Autonomous Region on the acquisition and use of water resources. At the same time, the water footprint per capita of the Tarim River basin decreased gradually from a maximum of 3042.05 m³⁄ man in 2016 to 2340.41 m³⁄ man in 2019.

As can be seen from Table 4, the virtual water inflow and export of the Tarim River basin decreased significantly in 2009, and the change rate of virtual water outflow of the Tarim River basin was −58.65% in 2009. One possible explanation is: The 2008 Olympic Games may promote the economic development and foreign trade of the Tarim River basin, which made the import and export virtual water volume of the Tarim River basin larger before 2009. However, the financial crisis in 2008 reduced the economy of trade partners of the Tarim River basin. Therefore, the inflow and export virtual water volume of the Tarim River basin after 2009 was affected. From 2012 to 2013, all kinds of virtual water volumes in the Tarim River basin increased, among which the export virtual water volume increased by 81.99%, while the ecological virtual water volume decreased by 32.99%, indicating that the ecological water was severely squeezed by other levels of water consumption, leading to environmental deterioration.

As can be seen from Table 4, water consumption of secondary industry in Tarim River basin increased steadily from 2009 to 2014. One possible explanation is as follows: The “Special Planning of Construction Projects in Three Prefectures of Southern Xinjiang” implemented from 2009 to 2013 and the national Counterpart Support work for Xinjiang in 2010 provided a large amount of human, financial and material support to the development of the secondary industry in the Tarim River basin, which promoted the development of the secondary industry in the Tarim River basin. After 2014, the water consumption of the secondary industry decreased slightly, which may be due to the strict regulations on the way and quantity of taking and using water in the Water Resources Management Regulations of Tarim River basin of Xinjiang Uygur Autonomous Region issued in 2014. In the 2016 economic and information Technology work conference, it was suggested that the strong development of industry may be the reason for the increase of water consumption in the secondary industry to the maximum of 499 million m³ in 2017.

Due to the poor business environment, the water consumption of the tertiary industry in the Tarim River basin decreased from 2008 to 2010, and increased slowly to the maximum value of 103.00 million m³ from 2014 to 2017, the water consumption of the tertiary industry in the Tarim River basin basically remained unchanged. In 2018, it dropped to the lowest level of 44.00 million m³.

3.1.3. Structural Variation Characteristics of Agricultural Water Footprint

Table 5. Virtual water content of agricultural and livestock products in Tarim River basin. (Unit: hundred million m³).

Item	2008	2009	2010	2011	2012	2013	2014	2015	2016	2017	2018	2019
Corn	17.25	20.78	20.27	19.78	20.85	22.23	32.70	26.96	27.37	24.85	15.75	16.43
Wheat	25.46	30.98	31.89	30.60	31.76	32.85	34.29	38.87	40.41	37.15	28.26	28.66
Rice	4.47	4.78	4.19	4.53	4.75	4.83	4.45	4.32	4.77	4.32	1.17	0.93
Potato	2.73	2.69	1.97	4.56	3.27	3.25	3.35	3.18	6.08	3.20	2.89	2.34
Cotton	64.42	61.43	61.11	69.69	73.39	73.88	113.50	103.39	130.14	110.08	96.97	99.96
Oils beets	1.02	1.31	1.19	1.05	1.17	0.97	1.15	1.67	2.21	4.85	1.48	1.31
Beet	0.80	0.95	1.12	1.08	1.31	1.27	1.11	1.10	1.34	1.26	0.96	1.49
Vegetables	11.09	14.49	13.42	15.20	14.70	15.00	16.00	16.38	21.02	17.79	13.96	16.22
Fruits	25.62	33.87	35.44	36.91	69.10	72.91	52.98	66.96	69.33	72.06	59.44	74.47
Pork	4.58	4.93	5.91	6.83	6.51	6.91	7.94	8.49	9.55	5.25	12.49	12.34
Beef	21.59	22.42	24.07	24.32	24.46	26.05	25.97	26.82	27.08	18.76	18.00	19.62
Mutton	17.02	15.32	15.89	16.99	17.25	17.91	19.41	21.13	26.27	16.40	15.85	15.67
Poultry	2.82	3.42	4.14	4.46	4.88	6.36	7.06	8.11	8.45	1.64	1.51	1.97
Eggs	2.43	2.77	3.13	3.55	3.84	4.41	5.04	5.90	6.30	4.72	4.18	4.31
Milk	4.44	4.76	5.30	5.72	6.26	6.44	6.85	7.59	8.04	6.65	4.90	5.20
Aquatic products	1.69	1.76	1.85	2.12	2.39	2.53	2.78	2.81	2.87	2.89	2.29	2.33

Data source: According to the statistical yearbook of Xinjiang.

shows the virtual water content of agricultural and livestock products in The Tarim River basin. The virtual water content of plant products, mainly cotton, fruit, and wheat are more than that of animal products mainly pork and mutton, among which the virtual water content of cotton is the highest and the virtual water content of beet is the lowest. The virtual water content of cotton in 2019 is 9.99 billion m³. In the same period, the virtual water content of sugar beet is 149 million m³. One possible explanation is that the cotton planting quantity is large in the Tarim River basin, and the virtual water content of cotton per unit is 3.81 m³/kg, which is much higher than that of sugar beet per unit (0.10 m³/kg). In the Tarim River basin, because the long illumination time and the large temperature difference between day and night are conducive to the storage of sugar in all kinds of fruits, the proportion of cash crops is relatively large and increasing year by year.

Among animal husbandry products, the virtual water content of beef and mutton ranked first and second, respectively. From 2008 to 2019, the virtual water content of beef and mutton averaged 2.33 billion m³ and 1.79 billion m³ respectively, which may be related to the dietary habits of people in the Tarim River basin. From 2008 to 2016, the general trend of animal husbandry products was on the rise, among which aquatic products, eggs, and poultry increased steadily, while pork, beef, mutton, and milk showed a zigzag rise. From 2016 to 2017, the virtual water content of six kinds of animal husbandry products decreased to varying degrees, but the virtual water content of aquatic products increased slightly. The virtual water quantity of a large number of agricultural and livestock crops decreased to varying degrees from 2016 to 2019. It may be related to the circular of The State Council on Printing and Distributing the National Agricultural Modernization Plan (2016–2020), which proposed to reduce the planting area of some agricultural products and develop animal husbandry moderately, the 13th Five-Year Plan vigorously advocated water saving, and the Regulations on the Management of Water Resources in the Tarim River basin of Xinjiang Uygur Autonomous Region since 2014.

3.2. Water Footprint Evaluation Index System

According to the water footprint evaluation index system proposed by Qi et al. [42], the water footprint evaluation index system of Tarim River basin in

Table 6. Evaluation index system of water footprint in Tarim River basin.

Year	Annual Water Availability (Billion m3)	Water Resource Self-Sufficiency Rate (%)	Ten Thousand Tons of WFP Population Density (Person)	WFP Economic Benefits (Yuan/m3)	WFP the Density of the Land (m3⁄ km2)	WFP Net Trade Value (m3)	WFP Conversion Rate (%)	WFP Conversion Rate	WFP Scarcity Index (%)
2008	43.67	98.33	6.97	8.96	$1.39\times {10}^4$	$6.96\times {10}^9$	15.94	1.13	34.19
2009	36.37	99.57	5.09	6.59	$1.96\times {10}^4$	$2.89\times {10}^9$	7.95	1.75	57.54
2010	54.07	99.57	5.03	7.95	$2.03\times {10}^4$	$2.31\times {10}^9$	4.27	1.29	40.27
2011	45.83	99.66	4.75	9.09	$2.20\times {10}^4$	$2.14\times {10}^9$	4.67	1.34	51.40
2012	47.44	99.67	4.09	9.27	$2.56\times {10}^4$	$2.18\times {10}^9$	4.61	1.27	57.83
2013	50.29	99.73	4.32	11.03	$2.50\times {10}^4$	$4.06\times {10}^9$	8.07	1.34	53.17
2014	39.56	99.75	3.89	10.60	$2.88\times {10}^4$	$3.55\times {10}^9$	8.98	1.27	77.88
2015	34.04	99.57	3.65	10.35	$3.09\times {10}^4$	$2.19\times {10}^9$	6.44	1.78	97.20
2016	33.85	99.50	3.29	9.01	$3.43\times {10}^4$	$3.33\times {10}^9$	9.83	1.71	108.43
2017	32.80	99.30	3.97	11.75	$2.92\times {10}^4$	$3.22\times {10}^9$	9.80	1.37	95.28
2018	31.94	99.82	4.31	13.99	$2.65\times {10}^4$	$1.74\times {10}^9$	5.44	1.21	88.83
2019	33.89	99.77	4.27	15.67	$2.76\times {10}^4$	$2.26\times {10}^9$	6.67	1.27	87.21

Data source: According to the statistical yearbook of Xinjiang.

was worked out.

3.2.1. Evaluation Index of Internal Benefits of Water Footprint

1.

Population density of ten thousand tons of water footprint

In 2008, the population density of the water footprint of the Tarim River basin reached a maximum of 6.97 person/10⁴ t and then decreased year by year. After a slight increase in 2013, the population density continued to decrease and then increased again to a minimum of 3.29 person/10⁴ t in 2016. See (Figure 2) for details. The results showed that the effective force of water resources in the Tarim River basin showed a general downward trend from 2008 to 2016, and the number of people supported by the water footprint decreased year by year, while the effective force increased gradually from 2016 to 2019. One possible explanation is that under the guidance of the “12th Five-Year plan” (2011–2015) policy of the Xinjiang Autonomous Region, the output of characteristic agricultural products in Xinjiang has gradually increased, resulting in a gradual increase in agricultural virtual water volume, which has gradually reduced the effective force of water resources, this is manifested as a decrease in population density of ten thousand tons of water footprint, and thus resulted in the minimum effective force of 2016. Under the influence of policies such as the 13th Five-Year (2016–2020) Plan of Xinjiang Autonomous Region and the implementation of the river chief system in Xinjiang Autonomous Region, agricultural water consumption is gradually reduced, the utilization efficiency of agricultural water resources is improved, and the effective force of water resources is gradually increased, the population density of 10,000 tons of water footprint increases.

2.

Economic benefits of water footprint

It can be seen from Figure 3 that the economic benefits of the water footprint of Tarim River basin increased steadily from the lowest value of 6.59 Yuan/m³ to the maximum value of 11.03 Yuan/m³ from 2009 to 2013, indicating that the economic benefits of water resources of Tarim River basin increased rapidly and the utilization level of water resources increased significantly during this period. One possible explanation is that Xinjiang’s 12th Five-Year plan has increased the economic efficiency of water resources. From 2013 to 2016, the economic benefit value of the water footprint decreased slightly, indicating that the utilization level of water resources declined slightly. One possible explanation is that the “12th Five-Year Plan” promoted the development of agriculture with high water consumption more and more but failed to make its growth within a reasonable and controllable range. From 2016 to 2019, the economic benefit increased rapidly to the maximum value of 5.67 Yuan/m³ in 2019, indicating that during this period, the utilization rate of water resources has gradually improved, which may be affected by the agricultural modernization plan, the 13th Five-Year Plan and the River chief system of Xinjiang Autonomous Region.

3.

Land density value of water footprint

As can be seen from Figure 4, the land density of the water footprint of the Tarim River basin gradually increased to the maximum from 2008 to 2016, 34,292.07 m³⁄ km² in 2016, due to the lag of the policy, the water consumption per unit area was the largest in 2016. From 2016 to 2019, with the help of the 13th Five-Year Plan and the implementation of the river chief system in the Xinjiang Autonomous Region, the density of land with water footprint showed a downward trend.

From the perspective of the internal benefits of water resources in the Tarim River basin, the role of water resources in the Tarim River basin tends to weaken. After the production, processing, and planting of water resources, the economic benefits have been on the rise since 2016, but the rate of change of economic benefits has gradually decreased, and the water consumption per unit of land is large. On the whole, the efficiency of the Tarim River basin is not good, and there is still room for improvement.

3.2.2. Evaluation Index of External Benefits of Water Footprint

1.

Water footprint net trade volume

As can be seen from Table 6, the net trade volume of the water footprint of Tarim River basin is all positive, with the lowest value of 1.74 × 10⁹ m³ in 2018 and the highest value of 6.96 × 10⁹ m³ in 2008, which is a typical water resource outlet. Show that in the process of foreign trade, the Tarim River basin, mainly for export, the Tarim River basin water resources within the outflow is relatively serious, at the same time, the Tarim River basin is unable to supply water, water is relatively fixed, and the amount of water in water change is small, with the development of the Tarim River basin, continues to large-scale water outflow, and imports less, it may have a negative impact on the ecology and economy of Tarim River basin.

2.

Water footprint contribution rate

As can be seen from Table 6, the contribution rate of the water footprint of the Tarim River basin was the highest in 2008, which was 15.94%, and decreased to 4.27% in 2010 after 2008. From 2010 to 2019, the contribution rate of water footprint increased with fluctuation, indicating that the contribution rate of the Tarim River basin to water resource pressure in other regions decreased first and then increased, and the average contribution rate of the Tarim River basin was 7.72%. The more it alleviates water resources pressure in other regions, the more unfavorable it is to the harmonious development of the local economy and ecology.

3.

Water footprint value conversion rate

As can be seen from Figure 5, the exchange rate of water footprint value in 2015 is the highest. In the process of foreign trade, each unit of water footprint exported in the Tarim River basin can be exchanged for 1.78 units of water footprint in other places. From 2008 to 2019, the average exchange rate of the Tarim River basin was 1.4, with relatively large fluctuations. The conversion rate of water footprint value of the Tarim River basin is lower than the average value in most periods, except that it is higher than the average value in 2009, 2015, and 2016, indicating that the Tarim River basin does not have an obvious advantage in the process of water footprint trading and has a large space for development.

To sum up, the Tarim River basin has good external benefits, and plays an export role in the process of foreign trade, alleviating the pressure on water resources in other areas to a certain extent, but it is not in a dominant position in the process of water footprint trade, this is not conducive to the sustainable development of the local ecology and economy. The sustainable development of local ecology and economy will be threatened if the output of water resources of Tarim River is much larger than the import due to the fixed water source and the inability to produce flow by itself.

3.2.3. Index of Water Resource Shortage

The water footprint of The Tarim River basin in 2016 was 108.43%, indicating that there was an extreme water shortage in the Tarim River basin in 2016. A possible explanation is as follows: The “12th Five-Year Plan” advocated the development of featured agricultural products, which increased the agricultural virtual water amount. However, the “moderate development” policy proposed by the agricultural modernization plan had a certain lag from release to implementation, resulting in the maximum amount of agricultural virtual water amount in 2016 and the extreme shortage of water resources. Except for 2016, the water resource scarcity index in all other years was less than 100%, indicating that there was no serious water shortage and water supply exceeded water consumption. As can be seen from Figure 6, the water resource shortage index of Tarim River basin increased rapidly from 2013 to 2016, with the highest growth rate of 46.49% from 2013 to 2014, indicating that the water shortage situation of Tarim River basin is aggravated year by year. After 2016, perhaps due to relevant policy factors, the scarcity index gradually decreased, and the decline rate gradually slowed down.

3.2.4. Self-Sufficiency Rate of Water Resources

The Tarim River basin is highly dependent on local water resources. It can be seen from Table 6 that during 2008–2019, the self-sufficiency rate of water resources in The Tarim River basin averaged 99.52%, the highest value was 99.82% in 2018, and the lowest value was 98.33% in 2008. It is mainly affected by the geographical location of the Tarim River basin and the small amount of imported virtual water.

3.3. Decoupling Analysis

The water footprint of the Tarim River basin each year was obtained through the water footprint model, and the decoupling model was constructed. Figure 7 was obtained after analysis and judgment, and

Table 7. Coordination relationship between economic growth and water resource utilization in Tarim River basin.

Year	$\%\Delta GDP$ (%)	$\%\Delta WFP$ (%)	Elastic Index	Decoupling Judgement
2009	3.11	40.19	12.94	Expansionary negative decoupling
2010	25.61	4.05	0.16	Weak decoupling
2011	23.69	8.19	0.35	Weak decoupling
2012	18.68	16.45	0.88	Expansive coupling
2013	16.06	−2.55	−0.16	Strong decoupling
2014	10.76	15.25	1.42	Expansionary negative decoupling
2015	4.76	7.36	1.55	Expansionary negative decoupling
2016	−3.39	10.94	−3.23	Strong negative decoupling
2017	11.00	−14.86	−1.35	Strong decoupling
2018	8.12	−9.22	−1.14	Strong decoupling
2019	16.71	4.19	0.25	Weak decoupling
Mean	12.28	7.27	1.06	Expansive coupling
“The 12th Five-Year Plan”	14.79	8.94	0.81	Expansive coupling
“The 13th Five-Year Plan”	8.11	−2.24	−1.37	Strong decoupling

Data source: According to the statistical yearbook of Xinjiang.

and Figure 8 were obtained according to Figure 7. The decoupling relationship between water resource utilization and economic growth is further interpreted by using the water footprint evaluation system.

As can be seen from Figure 7, during 2008–2019, the overall relationship between economic development and water resource consumption in Tarim River basin was not good. The best strong decoupling occurred only 3 times, accounting for 25%, and the strong decoupling and weak decoupling occurred 6 times, accounting for only 50%. Expansionary negative decoupling, strong decoupling, and weak decoupling all appeared 3 times, ranking first at the same time. As can be seen from Table 7, the decoupling index showed an upward trend from 2010 to 2015, and the degree of decoupling gradually became worse. Economic growth and water resource consumption gradually became the same from the original deviation, indicating that economic growth increasingly depended on water resource consumption, that is, the economic growth of the Tarim River basin gradually increased its dependence on water resources during this period. The decoupling index rose again from 2016 to 2019, and the changing trend of GDP change rate and water footprint change rate increased simultaneously from 2017 to 2018. After a short period of strong decoupling in 2017 and 2018, weak decoupling occurred again in 2019.

As can be seen from Figure 8, during 2009–2019, the economic growth of the Tarim River basin was fast and fluctuated greatly, maintaining at 25.61%~−3.39%, with an average annual GDP growth rate of 12.28%. The change rate of GDP in 2009 was small, while the change rate of water resources utilization was the largest. A possible explanation is as follows: Tarim River basin, with the much slower GDP growth, is likely to be affected by the financial crisis in 2008, at the same time, the financial crisis makes the economic decline in the Tarim River basin trading partners and the total amount of foreign trade of the Tarim River basin, the Tarim River basin is an economy of small rises, based on a large amount of consumption on the basis of water resources. From 2010 to 2016, it gradually decreased to the lowest value −3.39%. From 2016 to 2019, the RATE of GDP change showed an upward trend, increasing to 16.71% in 2019, which may be related to “promoting structural reform and promoting sustained and healthy economic development” proposed at the Central Economic Work Conference in 2015.

By Figure 4 to Figure 8, the Tarim River basin water footprint rate fluctuation is relatively obvious, the average rate of 7.27%, water footprint of the Tarim River basin, the average GDP rate significantly higher than the average rate of change of water footprint, most of the year, greater than 0 indicates that water footprint overall growth trend, influenced by policy in 2017, its lowest rate, water footprint was −14.86%, indicating that the water footprint decreased the most.

According to the distance between the two curves in Figure 8, the degree of dependence between water resource utilization and economic growth can be roughly judged. From 2008 to 2016, the distance between the two curves gradually decreased, indicating that the dependence of economic growth on water resources gradually increased. From 2016 to 2019, the distance between the two curves was large, indicating that the dependence was small. However, the curve showed a trend of close, and the distance between the curves gradually decreased, indicating that the dependence gradually increased. In Figure 4, the change rates of the water footprint in 2013, 2017, and 2018 are all negative, and the change rates of gross product in these years are all positive. In other words, with the increase in economy, the utilization of water resources gradually decreases, which can be judged as a state of strong decoupling. Only in 2016, the change rate of GDP was negative, and the change rate of conceptual water footprint was positive, that is, with the decline of the economy, the utilization of water resources gradually increased, which can be judged as a strong negative decoupling state between water resources utilization and economic growth.

3.4. Policy Interpretation of Decoupling Relationship between Water Resources Utilization and Economic Growth

In 2009–2015, the Tarim River basin water resources utilization in a state of decoupling between the economic growth most in weak decoupling (B), dilated coupling (G), and dilated swings between negative decoupling (F), providing aid to Xinjiang policy and “twelfth five-year” plan of Xinjiang autonomous region may be the Tarim River basin water footprint of the main causes of increase year by year, The virtual water amount of cotton and fruit in agriculture increased most obviously. As can be seen from Figure 9, the fluctuation trend of the change rate of virtual water amount of agricultural products, the change rate of water consumption of tertiary industry, and the change rate of water footprint from 2009 to 2015 remained basically the same, showing positive growth. At the same time, the change rate of water consumption in the secondary industry decreased synchronously with the change rate of GDP, indicating that the increase of water consumption in the secondary industry has a certain promoting effect on the growth of GDP. By water footprint internal evaluation index can be found that the period of the Tarim River basin water footprint per ten thousand tons can raise gradually decline, the number of per unit water footprint can produce economic benefits of the change rate of decline gradually, water consumed per unit area increased gradually, show that internal efficiency gradually reduces units of the Tarim River basin water resources, and poor water resource utilization. At this time, the change rate of GDP gradually decreased, revealing that economic growth during this period was too dependent on water resource consumption, and water resource utilization in economic growth did not show a good decoupling state.

2013 is the optimal state of strong decoupling, industrial water consumption increases to the third place, and the internal benefit indexes of the water footprint in this year all perform well. A possible explanation is as follows: The policy has provided a lot of support for the industrial development of The Tarim River basin. In the economic and Information Technology Work Conference held in 2012, it was proposed to implement the “15% average annual increase of industrial added value” and “tens of billions of projects” in the next five years, which once again promoted the industrial development of the Tarim River basin.

In 2016, the agricultural virtual water amount and water footprint increased to the maximum due to the policy lag. In 2016, the internal benefit performance of water footprint was poor, while the external benefit surface was good, and the water resource was seriously deficient, indicating that the utilization rate of water resource was poor in 2016, that is, with the economic recession, the consumption of water resource increased.

As can be seen from Table 7, 2017–2018 was in a strong decoupling state, indicating that with the economic development in these two years, the consumption of water resources gradually decreased, and the two were in an optimal state. According to the internal and external benefit indexes of water footprint, the utilization rate of water resources in Tarim River basin was high from 2017 to 2019, and the degree of water resource shortage gradually decreased.

One possible explanation for the improvement of water resource utilization in the Tarim River basin from 2017 to 2019 is that the 13th Five-Year Plan, agricultural modernization plan, and the implementation of the river chief system in Xinjiang Autonomous Region restrict the use of water resources. In the 13th Five-Year Plan, water-saving has been mentioned many times, water supervision has been strengthened, the water rights trading system has been promoted, and farmland has been further promoted to forest and grassland. The National Agricultural Modernization Plan (2016–2020) promulgated in 2016 has been adopted. Vigorously promote agricultural structure optimization, clearly points to “stable quality cotton planting area in Xinjiang”, be restricted to the high water consumption of crops planting area, the promotion of hardy series of means such as quality and water-saving soil conservation technology, 2017, promulgated by the State Council “about the comprehensive implementation of the views of the long river system is put forward to set up the layers of the long river on rivers under special management. As can be seen from Figure 9 industrial water consumption rate and GDP rate maintained synchronization growth or decline further shows the second industry development is conducive to the increase of the Tarim River basin GDP, probably because of the latter work conference in 2016 to promote industrial development, so the second industry water consumption from 2017 to 2018 at relatively high levels, The change of water resources utilization structure makes the economic growth of Tarim River basin less dependent on water resources consumption.

4. Conclusions and Suggestions

4.1. Conclusions

This paper uses water footprint theory, water footprint evaluation system, and decoupling theory to explore the relationship between water resources utilization and economic growth in Tarim River basin from 2008 to 2019, and draws the following conclusions:

Based on the water footprint theory, the water footprint of the Tarim River basin increased gradually since 2008 and decreased gradually after 2016. The internal benefits of water footprint were poor before 2016, and all three indicators improved after 2016. Its external benefits were strong from 2008 to 2016, but weakened slightly after 2016. The water resource shortage showed an overall upward trend, and gradually slowed down after the extreme shortage appeared in 2016. The self-sufficiency rate of water resources in the Tarim River basin is relatively high, the average is 99.52%, and the remaining 0.48% can be imported virtual water. The water footprint index shows that the water resources in The Tarim River basin are increasingly scarce, and the water resources play a small role in alleviating the water resource pressure in other areas.

Based on the decoupling theory, the decoupling state during the 12th Five-Year Plan period is worse than that during the 13th Five-Year Plan period, which changes from expansionary coupling to strong decoupling. The decoupling intensity increases gradually, and the dependence of economic growth on water resource consumption decreases gradually. The optimal decoupling state in 2013 may be due to the influence of counterpart assistance to Xinjiang, the Economic and Information Technology Conference (2012), and the 12th Five-Year Plan, while the strong negative decoupling in 2016 may be due to the influence of policy lag. The optimal decoupling in 2017 and 2018 may be influenced by Xinjiang’s implementation of the river chief system, agricultural modernization plan, and Xinjiang’s 13th Five-Year Plan.

Combined with water footprint theory and decoupling theory, we can see that the main factors influencing the decoupling relationship between water resources utilization and economic growth in the Tarim River basin are as follows: (1) The primary industry has the greatest influence on the relationship between water resources utilization and economic growth in the Tarim River basin; (2) The structure of water resources utilization is highly uncoordinated; (3) The supply of secondary and tertiary water consumption can promote economic growth; (4) Reducing agricultural water consumption will not cause economic decline; (5) Export trade is highly uncoordinated with import trade.

The possible contributions of this paper are as follows: (1) From the perspective of water footprint, this paper explains the relationship between economic growth and water resource change in the Tarim River basin since the Central Work Symposium on Xinjiang; (2) It provides new evidence for a comprehensive understanding of the theory of “two mountains” (lucid waters and green mountains are gold and silver mountains) and evaluation of the effectiveness of the policy of assisting Xinjiang and implementing the river chief system. (3) It provides a new way to understand the economic development of the basin.

Most of the previous research on water resources in the Tarim River basin focuses on supervision, utilization, and ecological conservation, and little research on the relationship between water resources and economy and provides corresponding countermeasures. Most of the relevant research on the Tarim River basin is on physical water, and virtual water is ignored. Only by basing on the water footprint study can the water resource loss situation of the Tarim River basin be fully and truly reflected. Although the decoupling model is used by most scholars, it is seldom used for the basin where “the river itself does not produce water flow” and is seldom analyzed in relation to policies. Research for a comprehensive understanding of China in recent years some of the major theories and policies, such as the “two mountains” theory (lucid waters and lush mountains are invaluable assets) and evaluate the counterpart of Xinjiang, carry out the policy according to long river system result provides new evidence, as well as full understanding in a continental river basin in China and underdeveloped regions in economic development, provides new ideas and solutions.

4.2. Suggestions

From the perspective of water footprint, the suggestions are as follows: reducing the water footprint of the Tarim River basin, improving the internal benefit of water resources, reducing the external benefit, alleviating the shortage of water resources, and reducing the self-sufficiency rate of water resources, including: (1) reducing agricultural water consumption and adjusting agricultural planting structure; (2) Improve the water footprint structure and increase the water consumption of secondary and tertiary industries; (3) Enhance the added value of products and improve the economic benefits of water resources; (4) Improve the virtual water import volume, reduce the self-sufficiency rate of water resources, balance the virtual water import and export structure.

Reducing the rate of change of water footprint and increasing the rate of change of GDP can strengthen the decoupling intensity between water resources utilization and economic growth in the Tarim River basin, mainly including the following suggestions: (1) further promote effective agricultural water-saving policies; (2) Vigorously develop the secondary and tertiary industries; (3) Encourage the design and research and development of high-tech and high value-added products. (4) Vigorously popularize agricultural water-saving technology, implement stepped water pricing and agricultural water-saving compensation policy, improve agricultural water efficiency, and improve economic benefits of water resources from all aspects.