A Comprehensive Post Evaluation of the Implementation of Water-Saving Measures in Xiangtan, Hunan Province, China

: Water resource is an important foundation to support industrial and agricultural produc-tion, in the maintenance of national energy security role is irreplaceable. Water conservation and the effective use of water resources are essential for achieving sustainable development in China. The construction of water-saving society is a prerequisite for realizing efﬁcient utilization of water resources and an important strategic development for moving towards environment-friendly society. This study established an index system to evaluate the implementation of water-saving measures in Xiangtan, Hunan province, China. The index system incorporated ﬁve aspects: (1) comprehen-siveness; (2) agricultural water; (3) industrial water; (4) domestic water, and; (5) aquatic ecology and environmental management. Analytic hierarchy (AH) was used to determine the weights of indices, and AH was integrated with grey relative analysis to establish a comprehensive system for the evaluation of the water-saving measures in Xiangtan. The results showed that the implementation of water-saving measures in Xiangtan is generally progressing well. However, industrial added value water consumption per 10,000-yuan remains at the primary stage and wastewater reuse remains limited. In addition, water use per 10,000-yuan gross domestic product, the coverage of water-saving irrigation projects, industrial wastewater reuse, and the leakage rate of urban water supply network remain at an intermediate stage. The result of this study can scientiﬁcally reﬂect the level of the water-saving measures in place in Xiangtan and could guide future implementation of water saving measures in Xiangtan and in other cities.


Introduction
Water resources are becoming increasingly limited under the impacts of global economic development, climate change, and continuous population growth. Especially because of the discharge of industrial, agricultural and domestic wastewater, the water environment pollution is particularly prominent [1,2] (Fares R2015 and. Therefore, there has been an increasing focus, both among regulatory agencies and academia, in identifying methods of improving the efficiency of utilization of water resources [3,4]. At present, many countries have not put forward the concept of water-saving society, the construction of water-saving society has not been formed, lack of experience [5]. The existing research is mainly, Sweden, Israel and other countries simply in the field of water demand management has made some theoretical model. Scholars of various countries focus on the impact of economic benefits on economic behavior, but there is little research on water-saving evaluation. Although there is a certain understanding of the research on water-saving society and its importance at present, there is a lack of systematic in-depth analysis on the connotation, evaluation system and incentive mechanism of water-saving society. At present, China's first batch of water-saving society construction pilot is facing the urgent task of acceptance. How to scientifically and rationally evaluate the performance of the construction of water-saving society is the construction of water-saving society is an urgent need to answer the question, is also a basic guarantee of the effective implementation of the construction of water-saving society. The implementation of water saving measures not only facilitates the efficient use of water to avoid wastage, but also reduces discharge of wastewater to the environment, thereby having less impact on the aquatic ecology [6]. Establishing water saving measures is therefore one of the essential measures required to achieve sustainable development in China. Water saving measures have been piloted in various cities in China, all of which have committed to achieving targets of water consumption per unit of gross domestic product (GDP) and per-capita water consumption through the formulation of a total water consumption index and the implementation of a water supply plan [7][8][9]. To develop water-saving society construction after evaluation, will provide reference for the related research, is conducive to promoting water saving work in China, the implementation of resource, economy, society and ecological environment coordinated development, and for regional water environment protection and sustainable utilization of water resources to provide scientific decision basis. The present study conducted a post evaluation of the implementation of water saving measures within Xiangtan, one of the pilot cities in which the water saving measures have achieved a degree of maturity. The aim of the present study was to explore the different measures, evaluate their effectiveness, and analyze persisting challenges. It is hoped that the results of the present study can promote the further implementation of water saving measures in pilot cities and that the study can act as a reference for the implementation of water saving measures in other regions [10][11][12].

Literature Review
Most existing studies on water conservation have focused on policies and various water saving measures, and relatively few studies have analyzed the effects of these measures on society after they had been implemented, including a few studies in China. Wang et al. [13] evaluated the effects of water saving measures in a city located in the Chengdu plain using analytic hierarchy process (AHP). Yan et al. [14] established a fuzzy AHP model for evaluating water saving measure, which they applied to the Nianchu River Basin in Tibet. Che et al. [15] used the Pressure-State-Response (PSR) model to establish an index system for the comprehensive evaluation of water saving measures in a city, which they applied to the city of Yangzhou through principal component analysis (PCA). Zhao et al. [16] established an index system to evaluate water saving measures using matterelement analysis and calculated the weights of indices according to their contributions to total water savings, which they applied to evaluate the effect of water saving measures in Shanghai. Li et al. [17] proposed the water savings evaluation method TOPSIS (Technique for Order Preference by Similarity to an Ideal Solution), which is based on the AHP method, to evaluate the effects of water saving measures in Guangdong province.
While the AHP and fuzzy evaluation methods have been widely adopted within studies of water saving measures, PCA and matter-element analysis have been seldom applied. The current study established a water savings evaluation index for Xiangtan which represents all stages of the implementation of water saving measures. The AHP method was used to determine the weights of the evaluation indices, thereby constructing a comprehensive model for evaluating saving society measures in Xiangtan through integrating grey relative analysis (GRA) with AHP. The method was previously applied to evaluate the status of water saving measures in the city of Jiangyin.
The establishment of a complete and scientific index for evaluating water saving measures is necessary for the setting of scientific water savings targets and for scientifically assessing progress in water conservation initiatives in various cities and regions. It would not be optimal to apply the same water savings evaluation method to all cities, and instead the evaluation standard should be set according to the specific water resources, level of economic development, and development plans of the various regions. The construction of water-saving society is a multi-level and multi-factor complex system, which is a typical gray system in which part information is known and part information is unknown. The Sustainability 2022, 14, 4505 3 of 10 evaluation indexes of water-saving society construction in Xiangtan city are calculated by grey correlation analysis. On this basis, the analytic hierarchy process (AHP) is used to synthesize and calculate each correlation degree. The evaluation result obtained in this way is more accurate than that obtained by using a single one of the methods. The present study conducted a post evaluation of the implementation of water saving measures in Xiangtan, Hunan province, China using a method that integrated AHP and GRA, with the former used to determine the weights of indices and the latter used to comprehensive analyze and evaluate the indices.

Determination of the Weights of the Evaluation Index
The Chinese Ministry of Water Resources approved the city of Xiangtan, Hunan Province as a pilot city for the implementation of water saving measures in April 2008. The construction of the evaluation index system was based on data for water saving measures implemented in which for 2011 and 2015. The index system consists of 19 indices in five categories: (1) comprehensiveness; (2) agricultural water; (3) industrial water; (4) domestic water, and; (5) aquatic ecology, environment targets and water saving management [18][19][20]. Table 1 shows the values of all the evaluation indices. The current study established an index system for evaluating water saving measures in which based on the indices in Table 1 and constructed an evaluation analysis model for the implementation of saving society measures in Xiangtan and for the determination of the weight of each index. The relative weight of each evaluation index was calculated according to the root method of single hierarchical arrangement: In Equations (1)- (3), q i is to the weight of each sub-index, n is the number of indices, and b ij is the scale value between two indices [19] (see GB-T28284-2-12). Table 2 shows the calculated weights of the indices.

Grey Relative Analysis
The GRA method is a branch of grey system theory which is used to assess the degree of correlation between a reference sequence and a comparison sequence according to the similarity in the geometrical shape of their curves [21]. The basic steps of the GRA method are as follows: (1) Determine the reference sequence X 0 (k) and comparison sequence X i (k), adopt the indices of the evaluation area as the reference sequence and adopt the standard indices of the evaluation stage as the comparison sequence.
(2) Standardize the sequence as the evaluation could be affected by different models, dimensions, and index units through range transformation [22].
For the benefit-oriented indexes, the benefit of the index increases with increasing value: For the cost indices, the benefit of the index increased with decreasing value: (3) Calculation of the sequence of absolute deviation, (4) Calculation of the correlation coefficient, In Equations (4)-(9), ρ is the resolution coefficient, with ρ ∈ (0, 1) and usually assigned a value of 0.5.
(5) Calculate the correlation coefficients of the indices of each criterion layer and list the related sequence. The stage with the highest correlation coefficient is adopted for the criterion layer. The correlation coefficients of the indices of each criterion layer were calculated according as: In Equation (1), ω(k) is the weight of the index of each criterion layer calculated through the AHP method. Calculate the total weighted degree of relevance and list the correlation sequence. The stage with the highest degree of correlation was adopted for the water saving measures. The total weighted correlation degree was calculated as: In Equation (11), ω(k) is the weight of the index of each criterion and was calculated through the AHP method.

Overview of the Study Area
The city of Xiangtan is in the north-central part of Hunan province along the banks of the Xiangjiang River and extends for~81 km from south to north and~108 km from east to west with a total land area of 5015 km 2 [23]. Xiangtan borders the city of Zhuzhou to the east, Hengdong, Hengshan, and Shaungfeng to the south, the city of Loudi to the west, and Ningxiang, Wangcheng, the city of Changsha and Changsha county to the north. The terrain of Xiangtan is high in the southeast, northwest, and southwest, tilted to the northeast, and relatively flat in the central parts. Xiangtan falls within a subtropical humid monsoon zone, and therefore has high vegetation cover, a developed river network, and abundant precipitation. The average annual precipitation of Xiangtan is 1362 mm whereas the average annual water surface evaporation (E601 evaporator) ranges between 700 and 900 mm, with low regional and interannual variation. Water resources are abundant in the Xiangjiang River Basin, with an average annual runoff depth of 751 mm (Xiangtan People's Government of Hunan Province, 2009).

Construction of the Index System for Evaluating Water Saving Measures
The use of many indices increases the rationality, comprehensiveness, systematicity, and operability of the index system proposed in the current study for the evaluation of water saving measures in the city of Xiangtan [24]. The implementation of water saving measures was divided into five stages based on the water saving index: (1) the initial stage; (2) the primary stage; (3) the intermediate stage; (4) the operation stage; (5) the maturity stage. The criteria for the deriving the stages can be found in the literature [25][26][27]. The qualitative index was quantified and then divided into standard stages from 0 to 10 to correspond with a quantitative index [28]. Table 3 shows the evaluation index system and the division of stages of the implementation of water saving measures.

Grey Relative Analysis
The relative discrete data of each evaluation index for the various stages of the implementation of water savings were analyzed based on grey relative analysis. Table 4 shows the correlation between each evaluation index and each stage of the implementation of water saving measures. As shown in Figure 1, among all the evaluation indices, water consumption per 10,000-yuan industrial added value and per-capita domestic water consumption of urban residents were shown to be in their initial stages, the rate of wastewater reuse was in a primary stage, the decline in water consumption per 10,000-yuan GDP, coverage of water-saving irrigation projects, industrial water recycling rate, and the leakage rate of the urban water supply network were all in an intermediate stage, and all remaining indices were in an operational or mature stage.

Grey Relative Analysis
The relative discrete data of each evaluation index for the various stages of the implementation of water savings were analyzed based on grey relative analysis. Table 4 shows the correlation between each evaluation index and each stage of the implementation of water saving measures. As shown in Figure 1, among all the evaluation indices, water consumption per 10,000-yuan industrial added value and per-capita domestic water consumption of urban residents were shown to be in their initial stages, the rate of wastewater reuse was in a primary stage, the decline in water consumption per 10,000yuan GDP, coverage of water-saving irrigation projects, industrial water recycling rate, and the leakage rate of the urban water supply network were all in an intermediate stage, and all remaining indices were in an operational or mature stage.  Relative Discrete Data of Each Index among the   Table 5 shows the comprehensive evaluation results for the implementation of water saving measures in Xiangtan city, where it is evident that the comprehensive, agricultural water, aquatic ecology and environment target, and domestic water indices are in the operational stage, the industrial water index is in its initial stage, and the water saving management index is in the mature stage. By combining with the criterion layer of the evaluation, the results of the comprehensive evaluation indicate that the implementation of water saving measures in Xiangtan is generally in an operational stage.

Conclusions and Policy Implications
The results of the comprehensive evaluation of water saving measures Xiangtan, Hunan province, showed that implementation of water saving measures is dependent on a steady development of the national economy, cooperation by the local government, and enhanced awareness of water saving measures among residents. The evaluation also showed that the implementation of water saving measures continues to face challenges in reforming the management system, in the establishment of water rights, and in the water market. The volumes of public and domestic water use are increasing with socioeconomic development. Therefore, the implementation of water saving measures should consider the challenge of increasing water consumption in various fields while emphasizing the importance of water conservation.
The evaluation of water saving measures implemented in Xiangtan showed that the comprehensive, agricultural water, aquatic ecology and environment targets, and water saving management indices are within the operational and mature stages, thereby indicating that the water saving measures taken by the Xiangtan government for the above five indices have had a positive effect on the final evaluation. The water saving measures implemented in Xiangtan from 2008 to 2015 have achieved a positive effect in general, while some challenges persist. Given the results of the current study, some suggestions for overcoming these challenges can be given: (1) The industrial water index remains in the initial stage. Local government should strengthen the regulation of industries with large water consumption to ensure appropriate water saving measures, such as installing water saving and water treatment equipment to improve the rate of utilization of reclaimed water. The government should strengthen awareness of water saving measures among residents and popularize water saving habits. (2) The rational exploitation and utilization of water resources and the implementation of water charges should be strengthened, and subsidies and water licenses should be revoked to ensure the societal adaptation to strict water resources management.