Water quota system in China: problems and countermeasures

Water resources are the foundation of economic development, social progress and ecological security, and water shortage is the primary problem facing China. Water quotas have great practical significance for the resolution of water shortages to achieve sustainable use of water resources and sustainable development of the national economy. In this study, to analyse the problems and countermeasures of the water quota system in China, the water quota system progress domestically and abroad, the water quota problem in China, and the countermeasures for the water quota problem are summarized. The data validity test, spatial correlation test and consistency test are used to test the rationality of water use quota. And the specific countermeasures are presented: improving the water quota system, defining its concept, and revising its scheme, etc. This study provides the support to standardize water quotas and implement the effective water conservation policies of China.


INTRODUCTION
With the increase of economic and social development, the contradiction between people and water resources in China has become increasingly prominent. And industrial water and domestic water have increased by 10.71% and 52.73% respectively in the past 20 years. Additionally, water problems such as drought, water shortage, soil erosion and water environmental pollution have appeared. Therefore, the issue of water resources is the primary issue facing China. Water resources, together with grain and oil, have become China's important strategic resources. To solve the contradiction between human and water resources, it is necessary to strengthen the unified management of water resources. Through rational use and effective protection of water resources, promote the sustainable use of water resources. As the important natural resource, water resources have irreplaceable ecological and economic values. Whether it is to maintain ecological balance or develop economic society, the demand for water resources is huge. The harmony between economic development and water consumption is to ensure that water resources will not be excessively consumed while realizing total economic growth.
The way to solve the problem of excessive water consumption is to build a water-saving society in an all-round way, and the establishment of water quotas is the prerequisite and key to a water-saving society. Water quota refers to the water consumption per unit product, unit area or per capita in unit time. With the rapid social and economic development of China, the gap between the supply and demand of water resources has become increasingly prominent (Cheng & Hu ). To improve the utilization efficiency of water resources, there has been an increasing number of studies conducted by Specifically, in 2011 a top objective outlined by the central government was to develop a strict water resources management system known as the 'three red line system', which has jurisdiction over the total amount of water used, the water usage efficiency, and the pollution limit in water functional areas.
The rule highlights new requirements and challenges for water quotas. In 2015, the 'ten-measure actions' issued by the Ministry of Environmental Protection was designed to control pollutants and the total quantity of water and to improve the water use efficiency. Water quota management has become a key research focus in current water resources science.
Currently, 30 provinces, autonomous regions and directcontrolled municipalities have established water quotas.
However, the current research on water quotas is still mainly at the level of formulation, revision, and management.
Related evaluation research is still in the exploratory stage, lacking corresponding theories and methods. In addition, there is insufficient systematic assessment of the existing water quota system, resulting in the current water quota system without a unified standard for measurement. This makes it difficult to compare different water quotas horizontally, and the establishment, revision and implementation of water quotas lag behind. Therefore, a large number of current water quotas have long been unable to adapt to the current situation and have caused more problems for the general application of water quota management. And unreasonably established water quotas reduce the water use efficiency and negatively affect the implementation of water consumption quota management measures. In general, the test of water quota rationality deserves more attention and requires urgent development to improve the water use efficiency.
In summary, this study proposed the problems and countermeasures of water quota system in China by analysing the present situation of the water quota system. The objectives are to conduct the following: (i) progress of water quota systems domestically and abroad; (ii) water quota problems in China; (iii) countermeasures for water quota problems in China. This study can provide theories and methods for the evaluation of water quotas in China, and help the government and water management departments to continuously regulate the efficiency of water quota management.

Principle of the correlation test
For provincial administrative units, the method of the outlier data test based on the median is usually adopted in rationality verification. Taking samples at the 0.25 fractile (lower quartile) as Q 1 , 0.5 quantile as Q 2 , and 0.75 fractile (upper quartile) as Q 3 , we receive four open intervals (À∞, Q 1 ), (Q1, Q 2 ), (Q 2 , Q 3 ), and (Q 3 , þ∞). Let Q d denote the separation distance (Q 3 -Q 1 ) between the upper quartile and the lower quartile. The normal values are located in the closed interval [Q 1 À Q d , Q 3 þ Q d ] and to be as the rationality interval (α refers to the coefficient of the rationality interval), while others outside of the interval are outliers signifying abnormal values. According to the actuality of water quotas and case studies, α ¼ 1:0 is selected as the coefficient of rationality interval at the present stage. In the future, with the development of industry, science and technology, as well as the adjustment of water quota values, the coefficient will be modified appropriately according to the actual situation.

Principle of the consistency test
The set of water quotas in a time series can be denoted as y 1 ), (x 2 , y 2 ), . . . , (x n , y n )} using the least squares estimation method to set up linear regression equation as follows: where β 0 denotes the constant, β 1 is the regression coefficient and ε is the random error.
In a given area for many years, x(n) denotes the water use of the nth year, so x(n þ 1) ∼ y, (n þ 1) ∼ y, x(n) ∼ x; let x(n) and x(n þ 1) represent the independent and dependent variables, respectively. The linear autoregressive model is: where β 1 can be calculated as: and β 0 can be calculated as: The standard error can be calculated as follows: The t-test is then applied to the autoregressive model to assess whether it has a linear relationship under the α significance level. The statistic of the t-test is presented as: If the quota value passes the significance test, it indicates that the quotas have a regression relationship in the corresponding time series with good consistency. If not, the residual error (r) and standardized residuals (e) i should be used to identify abnormal points which are defined by the relations: where y i is the observed value, y i is the predicted value, and Var(r i ) denotes the variance of the sample. In general, the abnormal points are identified by the characteristic that their standardized residual absolute values are greater than 2.

Technology roadmap
The roadmap of the countermeasures to improve China's water quotas are presented in Figure 1. Amir & Fisher , ), taking water-saving as a guideline for setting water quotas (Qiang & Lianhai ).
These guidelines govern industrial water allocations and control sewage water management (Cheng ).
Starting in the 1960s, Israel began to implement a water resources development license system and a water quota system that included water permits, quotas, and non-gratuitous water distributions (Friedler  (2) changing water rights to promote the rational use of water resources; (3) emphasizing water conservation; (4) restricting water use and wastewater discharge to promote reasonable water use; (5) coordinating the management of water resources; and (6) adopting flexible legislation in case of emergencies, among others. Many members of the ECE formulated the various water quotas by analysing the different types of water need, drainage and use habits, as well as assessing the water decrease due to consumptive water-using. The countries primarily focused on the raw material, the production method, the usage of a water management facility, the water cycle and the use of wastes and by-products. The current trend makes the quota standard more flexible with the use of economic stimuli. Simultaneously, quotas need timely corrections to adapt to environmental and technological developments.
In addition, the management models of some developed industrial countries have gradually turned from water-saving technology services to the integrated audit supervision aimed at water saving (Gagnon ; Özelkan & Duckstein ), and they put forward higher requirements on quota management. A water audit means checking and calculating water use (domestic, commercial and industrial), which is used to confirm the potential field of water saving and efficiency improving. A system water audit refers to validation

USA
The states established water right systems; the federal government focuses on water rights in water management; the water distribution and supply are primarily adjusted by the market and nongovernmental organizations spontaneously.

Russia
To combine the ecological benefits and economic benefits reasonably in water resources development, utilization and protection; priority should be given to ecology protection and human health.

Israel
To encourage water conservation; to increase water price; the water right quota was presented to distribute water resources, and users whose quantity is over the quota should be levied with a higher price according to the grade rates.
Singapore To carry out the water management law and regulation specifically and operably; to install water saving facility; to encourage water recycling in industry.
and calculation for production, delivery and allocation in a water system. The integrated water audit presents detailed instructions for water distribution systems to promote the efficiency of water resources management and the reliability of the water supply. Overall, these countries focus more on the management of quotas.
International studies on water quotas are also numer-

Water quotas in China
The water quota research started relatively late in China, but with continuous research progression, there are preliminary research studies on the formulation, management, and revision of water quotas (Table 2) plan was carried out nationwide, which put forward the procedure and method to guide regional water quotas. In 2012,  (Table 3), effectively promoting water resources management and the construction of water-saving infrastructures.
Developed areas such as Shanghai, Chongqing, and Beijing are the first that have issued water quota standards, as shown in Figure 2. Due to the special monsoon climate, Heilongjiang province, which suffers from spring droughts nine out of 10 years, issued the first industry water quota in 2000.
Inner Mongolia, Shanxi, Gansu, Ningxia and other arid regions also issued quota standards following Heilongjiang.
With the continuous improvement of water quota standards in various areas, the control and quota management of water resources continue to mature.

WATER QUOTA PROBLEMS IN CHINA
Outline of water quota issues By studying the progress of water quota systems domestically and abroad, we can see that the water quota is an important index for water management and a reasonable measurement in the industry for water use. For the concept of the water quota, there is currently no unified definition, which results in confusion during implementation. The overall meanings expressed by different scholars are similar in concepts, but have varying focuses (Table 4). It is necessary to clearly define the encompassing concept of the water quota in the analysis and research.
The idea of a 'limited quota', which is referenced more in the academic journals, emphasizing that a water quota is the water consumption limited quota under a certain condition.
From the perspective of government management, a water quota is a defined standard water quantity usage enforced to be followed by all users. An established water quota is straightforward and is the essence of 'water management ser- focusing on the management of water resources.
Formulation and management problems of water quotas Water quota is not only a measure to evaluate the level of regional water-using and water-saving but also a type of appraisal index. According to the regional and industrial analysis of the latest water quota regime, there are still problems concerning quota formulation and management in China.
The water quota formulation and standard system are incomplete These standards are primarily aimed at specific products rather than at an industry or enterprise as a whole. Although specific product quotas are scattered, they are divided meticulously, covered widely, and referenced. The comprehensive water quotas for industries is the key to understanding the integrative water quotas.
Determining the statistical scale of water quotas The basic determined method of water quotas in China is a statistical method rather than use of the demand method that is recognized internationally. Therefore, the scale  (2001) Part of industrial products water quota (trial) of Chongqing (2001) The Water Resources Bureau of Chongqing Part of industrial products water quota (2) of Chongqing (2006) Part of industrial products water quota (2) of Chongqing (2006) Agriculture water quota of Chongqing (2006) Agriculture water quota of Chongqing (2006) Non-production water quota standard of Chongqing Non-production water quota standard of Chongqing Water quota (trial) of Hubei (2003) The The Quality and Technology Supervision Bureau of Guizhou range of the statistical analysis has a strong influence on water quotas. In general, the larger the statistical scale, the smaller the water quota, and vice versa, mainly because the larger the statistical scale, the higher the degree of water reusage, which decreases the water quota relatively.
Overall, the water quota based on the basin scale is generally lower than the water quota that is based on a regional or urban scale of the basin.

Unclear relationships among water quotas
Currently, the commonly used water quotas include industrial quotas, agricultural irrigation quotas, domestic quotas, ecological quotas, among others. The water quotas are further divided into the 'water-using quota', the 'watertaking quota', the 'new water quota', among others. However, the relationship among the various quotas is unclear, which causes confusion in the formulation and management of water resources.

Limited flexibility in water quotas
Without considering the differences in water resource conditions and the economic status quo between different areas in one certain province, some areas are used to directly reference others' quotas. Most measuring units of quotas are product based, which also limits their flexibility.

Varying formulation methods of water quotas
There are various types of formulation methods and principles of water quotas in China. The formulation is not in conformity with basic requirements of standardization, simplification, coordination and optimization. Taking agricultural water  With a certain production technology and management, the reasonable water-using standard of unit production creating a per unit of output or providing a per unit of service.

Units of measurement
Within a certain period and range, the stipulated water consumption quota in an accounting unit under a constraint condition (Taolu et al. ).

Limited quota
In a certain period, the standard of water quantity complied by water units or people engaged in an activity and expressed as a limit of quantity ( Junwu ).

Government regulations
In a certain period, the water quota approved by the reasonable water consumption of the city industries according to the corresponding accounting unit (Jiang et al. ).

Time range
Under a certain technological condition and management level, the water consumption (or occupation) standards for the verification of the rational utilization of water resources (Cai et al. ).

Technological condition and management level of water resource systems
The certain standard of water amount in the process of water-using (Xiugui et al. ).
Water-using process quotas for example, the values could be largely different due to the diversity among soil conditions, crop varieties, water-using scopes, and terrains in various areas, which are also attributed to the different calculation methods and data sources.
The formulation method does not comprehensively reflect the changing structure of water-use and the actual water demand The water quota is a dynamic index that is subject to revisions every 3 ∼ 5 years according to changes in water degree, adjustments of product structures and quota implementation. Currently, the formulation is based on a statistical method, a kind of analysis ex post, requiring a long time series of statistical data. This method may not be suitable to the rapidly changing situation of water-using structures and water demand in China.

Outline of water quota issues
According to the present study, three aspects of the water quota irrationality are summarized as follows (

Validity test
Data validity ensures that each index has the correct data type, format, and effective data range. The data validity test of water quotas requires that the values are of the numeric type, and the industry quota units must be unified to analyse data between different regions. Quota validation is the basis of data space analysis and consistency analysis.
The water quota integrity should be considered as well, including referential planning quotas, instructive design quotas and mandatory management quotas. The index system should comprise agricultural, industrial, service industrial and domestic water quotas (and even to consider the ecological environment water quotas).
In consideration of the differences in water resources and economic and social situations among different provinces, the given product generally does not only have a fixed standard. The water quota interval is based on the characteristics of local water conditions to examine if the quotas are in reasonable intervals (Yong-Min ).

Spatial correlation test
The spatial correlation of data, within the same scale of the study area, should distribute smoothly in space, and significant abnormal values should not exist. Otherwise, abnormal values indicate that the quota does not meet the requirements of rationality. The purpose of the spatial correlation test is to identify abnormal points of water quota values in all study areas. The formulation of water quotas needs to consider regional differences because of economic diversity.
Given the unevenly spatial distribution of water resources, Northern China is water deficient, while southern China is rich in water resources, and the Qin Mountains -Huai River is regarded as the main line dividing China into north and south areas (as shown in Figure 3). Agricultural water usage has a close relationship with the local climate. To eliminate the influence of the climate factor on the rationality test, the case study is conducted in both south and north areas.
We take agricultural water quotas as examples to analyse its rationality. Agricultural water has a close relationship to the category of local crops. For the purpose of avoiding such interference factors on the rationality test, we test the irrigation water quota of summer corn with a 75% confidence probability of irrigation water in northern China and test the irrigation water quota of rice with a 75% confidence probability of irrigation water in southern China, as shown in Figure 4.
The rationality intervals in both regions are calculated by the method of outlier data test based on the median, and the results are presented in Table 5.
The rational interval of the irrigation water quota of summer corn is approximately [46.8, 126.6] in northern provinces. Apparently, the outliers are 140 m 3 /mu for Liaoning province, 235 m 3 /mu for Qinghai province and 320 m 3 /mu for the Xinjiang Autonomous Region. The water quota of rice is approximately [194, 615.5] in southern provinces, and the abnormal value is 670 m 3 /mu in Shanghai. However, further analysis is still needed on whether the quotas are reasonable on the basis of local conditions. The crop irrigation quota is strongly influenced by the local climate environment. The northern regions are drier, in general, and the crop irrigation water demand is higher, while the southern regions are rainy so that water usage is lower.
There is potential for irrigation quota reductions, depending on the use of advanced water-saving irrigation technology and reasonable management methods.

Consistency test
Consistency means that a set of data shows a certain trend over time and should not be significantly different than adja-    Due to the duration of the time series of existing water quotas and the quantity of collectable data, domestic water is used as an example for a case analysis. The life water consumption (L/d) of resident students in one college during 2001-2010 is shown in Table 6 The standardized residual in the point of (2002,2003) is more than 2; therefore, it is theoretically an abnormal point. After field research, due to an enrolment expansion in 2003, the resident students' water consumption increased differently compared to the usual period. While the water consumption was steadily within a normal range over the next few years, this trend was attributed to the continuously advancing water-saving facilities.
The outliers in the correlation test and the consistency test may not be unreasonable. There are many reasons for abnormal values, such as the formulation by the relevant department, local economic levels, water-saving technologies, water-using habits, climate changes, and so on.
Therefore, the theoretical outliers may be reasonable. If the reason for the abnormal value can be determined, for example, the agricultural water quota is low because of advanced agricultural technology, undoubtedly, the quota of this region should not be adjusted. If the case is invalid, the reason for the abnormal value should be analysed as soon as possible and revised in time.

COUNTERMEASURES FOR WATER QUOTA PROBLEMS IN CHINA
Clarifying the concept of a water quota Currently, there are two kinds of water quotas in water resource management in China. The 'water-intake quota'  refers to the actual water from all kinds of sources extracted by water consumption units. The 'water-using quota' refers to the comprehensive water demand to guarantee normal operation, which is the sum of the intake water and the recycle water (Handan et al. ). The water-intake quota is often used in industries in which water reuse is common, and the water-using quota is adopted in industries in which water reuse is sparse. It is necessary to clarify the concept of water quota in analyses and research.
Improving the water quota establishment method and principles, techniques and approaches as well as revisions according to various industries and regional characteristics in time. 'The technical guidance (trial) of water quota formulation' has been followed in these works.
Currently, Tibet has not introduced a local water quota and the standard is not comprehensive. The water conservancy department should carry out research to refine the water quota of industry as soon as possible. Agricultural water quotas cover farm irrigation, fruit and grass field irrigation, and fishery and animal husbandry. Industrial water quotas cover professional production water, auxiliary production water (such as boiler water, air conditioning water, cooling water, etc.) and accessory production water. The hotel water quotas in southern China are generally higher than those of the northern region. This difference is primarily influenced by local habits and the weather difference. In the southern area, the water consumption of residents is higher than that of residents in the northern area. In addition, there are gaps between the provincial quota values. The three-star hotel water quotas are more than 1,000 L/bed in Fujian, Jiangxi, Hubei, and Guangdong Province. The value is approximately 10 times higher than that of Gansu Province, which has the national minimum value of 120 L/bed. These water quota outliers are reasonable. However, before 2007, the hotel water quota in Jiangsu Province was 2,300 L/bed, and it was ascertained that the outlier was unreasonable. This result provided the theoretical basis for data analysis. Finally, it was later revised as 600 L/bed.

Regular and nonscheduled revisions of water quotas
The water quota is a dynamic index that requires constant regular and nonscheduled revisions according to the new situation. The period of regular revisions can be every five years. A nonscheduled revision is implemented when renovated water-saving production processes or equipment are used, which contributes to a decrease in water consumption so that the original quota can no longer adapt to the actual situation which should be revised in time.
The improvement in people's living standards has caused the domestic water proportion use each year to increase. The rapid growth of industrial water usage has made water-saving a more pressing issue. Specifically, the five high water consumption industries of thermal power, textiles, petrochemical industry, papermaking, and metallurgy account for approximately 50% of the total industrial water. With the improvement of industrial production technology, the above five industries have used far less than the original quota standards. The original quotas no longer have an effect on water saving, and it is necessary to revise water quotas in a timely manner.
To study the relationship between water quotas and water use efficiency and their development patterns are more extensive than those in prosperous regions. Their higher water quotas also limit the further improvement of the water use efficiency. In conclusion, based on an efficient water-saving facility and low consumption production process, the water quotas should be gradually reduced in these areas through rationally dealing with the relationship between water quotas and water use efficiency.
Building an information platform of water quota management to manage water-intake and water-use The formulation, management, and revision of water quotas are related to data collection, analysis, the processing pro- The water consumption of 10,000 yuan (1 US dollar ≈ 6.30 Chinese yuan in 2012) GDP was 55.75 m 3 , falling by 58.1%. The water consumption of 10,000 yuan in industry was 16.47 m 3 , which fell by 49.9%. The farmland irrigation water use coefficient was 0.63, which increased by 5.0%.
Meanwhile, the reuse rate of industrial water increased from 65% to 89%. Houma has built control centers for a water-saving society by installing intelligent telemetry equipment that can carry out water real-time data monitoring and dynamic management, providing a construction reference for regions of water shortage.

CONCLUSIONS
This study analyses the problems in the Chinese water quota system, the irrationality of the integrity and availability of data and the temporal-spatial aspect. The consistency and rationality tests are presented, further clarifying the index and numerical attributes and time and spatial characteristics of water quotas. Finally, to address the existing problems, the aim of the national water department is to improve and refine the establishment method of regional industrial water quotas using the data rationality test methods to evaluate irrationality and analysing the reasons for the irrationality to revise the quotas in a timely manner. The above points provide support to further standardize China's water quotas, to enhance the efficiency of waterusing and to favourably carry out the water-saving policy.
However, along with the severe shortage of water resources, there is still a long way to go regarding how to reasonably and continuously develop the revision of water quotas. This issue requires a deep and comprehensive study on water-saving management measures, the implementation of total amount controls, the promotion of a standards system and the innovation of science and technology.