Dual Method for Comprehensive Evaluation of Sustainable Water Resources’ Utilization Capacity in Huangshui River in Yellow River Basin, China

Abstract

The evaluation of sustainable water resources’ utilization capacity in the Huangshui Basin is essential for effective management and development in the water-scarce regions of northwest China. This research provides valuable insights into the basin’s potential capacity for sustainable water resource use by developing a comprehensive evaluation index that addresses the following three critical aspects: climate factors, water resource systems, and socio-economic conditions. The evaluation is conducted using a dual method, as follows: the fuzzy comprehensive evaluation model and the ELECTRE III evaluation method. The results indicate that the Huangshui Basin’s water resources, as a whole, exhibit a medium sustainable utilization capacity. Climatic factors and socio-economic characteristics are the main factors affecting the sustainable utilization of water resources in the Huangshui Basin. Remarkably, both methods yield consistent results, indicating that the overall sustainable utilization capacity of the Huangshui Basin’s water resources is medium. Climatic factors and socio-economic characteristics are identified as the primary aspects influencing the sustainable utilization of water resources in the basin. Based on these findings, recommendations such as enhancing the introduction of external water resources, improving water resources’ management, and implementing comprehensive remediation efforts can help to elevate the level of sustainable water use. This research not only contributes to a deeper understanding of the basin’s water resources’ dynamics, but also serves as an important reference for informed decision making regarding sustainable utilization in the Huangshui Basin.

1. Introduction

Water scarcity and its social consequences are recognized as some of the most significant global risks, both in terms of likelihood and impact [1]. The increasing intensity of human activities, advancements in economic development, and the continuous expansion of industries, agriculture, and urban areas—especially due to rapid population growth—have resulted in environmental degradation, water pollution, and severe waste, making water resources increasingly scarce [2]. By 2015, 28 countries, primarily low- and middle-income nations, were experiencing water shortages. It is projected that, by 2050, approximately 44 countries, with a combined population of around 2 billion people, may face severe water scarcity [3]. Consequently, the sustainable use of water resources has become a pressing global issue, necessitating robust methods for assessing water resources’ sustainability [2].

The Huangshui River Basin, located in eastern Qinghai Province, China, is not only a vital ecological barrier, but also the political, economic, and cultural center of the province [4]. The implementation of the ‘Lanzhou–Xining City Cluster Development Plan’ and the ‘Ecological Protection and High-Quality Development of the Yellow River Basin’ underscores the Chinese government’s commitment to comprehensive water resource management in this area [5,6]. However, intensified human activities—such as overgrazing and cultivation—coupled with traditional farming practices have led to increased soil erosion and agricultural non-point source pollution, further exacerbating the existing conflict between water supply and demand [4,7,8]. Therefore, evaluating the sustainability of water resources in the Huangshui River Basin is of paramount importance.

Methods for evaluating water resource sustainability can be broadly categorized into the two following main types: indicator-based evaluation methods and model simulation methods [9,10,11,12]. Indicator-based methods evaluate sustainability by establishing a set of quantitative or qualitative indicators [13]. Common indicators include water availability, water quality, and ecological flow [14]. Li et al. proposed an evaluation method for the sustainability of water resources in typical karst areas, and selected the four following aspects to evaluate water resources: water resource system, water demand system, ecosystem, and socio-economic system. They studied the sustainability of water resources in Zunyi City, Guizhou Province [15]. Additionally, Mehri et al. evaluated the sustainability of large-scale water resource systems by considering the quantitative and qualitative aspects of environmental, economic, and water productivity [16]. Model simulation methods employ tools such as hydrological and ecological models to simulate the flow and distribution of water resources, allowing for an evaluation of the impacts of different management strategies on sustainability [9,17].

As statistical methods continue to evolve, various new evaluation approaches have emerged, including the analytic hierarchy process, fuzzy comprehensive evaluation method, data envelopment analysis, composite index, ecological footprint, projection pursuit, and entropy value method [18,19]. The fuzzy comprehensive evaluation method was first proposed by Zadeh, and is now widely used by academics [20]. Previous studies have focused on qualitative descriptions of water sustainability, but there has been a lack of quantitative research on the topic [21]. Yang et al. combined an improved fuzzy comprehensive evaluation model with the TOPSIS evaluation model to evaluate the sustainability of water resources in Yulin City [22]. The fuzzy comprehensive evaluation method can solve the problems associated with qualitative evaluation, but it is constrained by the weights of variables when considering multiple factors [23].

The ELECTRE III method, first introduced by Bernard in the late 1960s [24,25], has undergone various modifications through numerous studies [26,27]. Many researchers have successfully applied ELECTRE III in diverse contexts. Ezbakhe et al. used ELECTRE III to evaluate renewable energy selection schemes in Turkey [28]. Mohammad et al. studied water resource sustainability strategies in Shahrud, Iran, and showed that the rankings obtained by the ELECTRE III method were more reliable for decision makers to ensure sustainable development in the region [29]. However, this method has been used less in the evaluation of water resource sustainability. ELECTRE III provides a greater flexibility in expressing decision makers’ preferences, without requiring all uncertainties to be fuzzified [30]. Significantly, compared to the fuzzy comprehensive evaluation method, ELECTRE III is computationally complex, requires a high data quality, and subjectivity may lead to bias. In some cases, the fuzzy comprehensive evaluation method may be advantageous.

This study focuses on the Huangshui River Basin as a case study, constructing a sustainability evaluation index system tailored to the basin’s characteristics. A dual method of the fuzzy comprehensive evaluation method and the ELECTRE III method is utilized to evaluate the sustainable utilization capacity of water resources in the Huangshui River Basin. The analysis aims to evaluate the sustainability status and identify key limiting factors, ultimately providing insights and recommendations for the effective management and sustainable development of water resources in the region.

2. Materials and Methods

2.1. Study Area

The Huangshui Basin, located in the northwestern interior of China (98°49′–103°26′ E, 36°02′–38°22′ N), is in the eastern part of Qinghai Province, flanked by the east of Tianjun County, Muli Mountain, and the Qilian Mountains to the north. The basin, covering approximately 32,900 square kilometers, features a complex and diverse terrain, including high mountains, river valley plains, and low hills, with a topography that is narrow in the east and wide in the west (Figure 1). It serves as the economic, political, and cultural hub of Qinghai Province and is its primary agricultural production base. The region is densely populated, with its gross industrial and agricultural production accounting for over 60% of the province’s total, making it a vital pillar for Qinghai’s economic development [31,32].

Cities within the basin, such as Xining City, are not only the political center of the province, but also hold significant positions in economic and cultural spheres. The climate of the basin is characterized by typical alpine and arid conditions, with average annual temperatures ranging from 0.6 to 7.9 °C, featuring a large diurnal temperature difference and a small seasonal temperature difference. The annual precipitation varies from 300 to 500 mm, while the average annual evaporation rate is as high as 800 to 1500 mm, indicating significant water scarcity. Although the inter-annual variation in precipitation is minimal, the seasonal variation is pronounced and the distribution of precipitation is highly uneven across regions, leading to water shortages in certain areas during specific seasons.

Currently, the water resource development and utilization rate in the Huangshui Basin has reached 60%, with an average multi-year water shortage of 240 million cubic meters [32]. This high rate of exploitation reflects the dependency on water resources in the basin and also highlights the constraints of water scarcity on regional development. To foster sustainable development in the Huangshui Basin, there is an urgent need for a comprehensive evaluation of the sustainable utilization capacity of water resources. This evaluation aims to optimize water resources’ management, enhance water utilization efficiency, and ensure the coordinated development of the regional economy, society, and ecosystem.

2.2. Data

The data of the evaluation indexes used in this study come from the bulletin of Qinghai Province water resources (2010–2018), statistical Yearbook of Qinghai province (2010–2018), environmental status of Qinghai Province (2010–2018), comprehensive planning (no. 1182,2014), the planning of the project (November 2021) [31], and the second report (2017). In this study, the mean values of 2010–2018 were used as the evaluation data.

2.3. Method

2.3.1. Fuzzy Comprehensive Evaluation Method

The specific steps to apply the method are as follows:

(1)

Establishment of an Evaluation Index System for Sustainable Utilization Capacity of Resources

Building on previous research related to the sustainable utilization capacity of water resources, this study posits that the basin’s water resource system’s sustainable utilization capacity is an external manifestation of its natural attributes. This capacity is influenced by external factors such as climate change, water resource development, and utilization. By integrating these considerations with the characteristics of the Huangshui Basin, the main indicators affecting the sustainable utilization capacity of water resources are categorized into the three following groups: climate factor indicators, water resource system indicators, and socio-economic indicators. The analytic hierarchy process (AHP) is employed to construct a scientifically sound, rational, and operable evaluation index system to assess the sustainable utilization capacity of water resources. The calculation methods and attributes of each index are detailed in

Table 1. Evaluation index system of sustainable utilization capacity of water resources in Huangshui River Basin.

Objective	Criterion	Indicator	Calculation Method	Indicator Properties
Evaluation of sustainable utilization capacity of water resources	Indicators of climatic factors	Average multi-year precipitation/mm	Total multi-year rainfall/year	Positive
		Concentration of precipitation/%	Multi-year average ratio of maximum 4 consecutive months of precipitation to annual precipitation	Negative
		aridity index	Ratio of annual evaporative capacity to annual precipitation	Negative
		Annual Precipitation Extreme Ratio	Ratio of annual evaporative capacity to annual precipitation	Negative
	Indicators for water resource systems	Water deficit/%	Ratio of water deficit to total water supply	Negative
		Surface water resources’ development and utilization/%	Ratio of total water use to total water resources	Negative
		Ratio of inter-basin/regional transfers to local water resources/%	Inter-basin transfers/total water resources	Negative
		Water quality compliance rate of water functional areas/%	Number of water quality attainment sections in water functional zones/total number of sections in water functional zones	Negative
	Socio-economic indicators	Water resources per capita/m3	Total water resources/total population	Negative
		Water consumption of ten thousand CNY output value/(m3/ten thousand CNY)	Total water consumption/total GDP	Negative
		Population density /people/km2	Total population/basin area	Negative
		Per capita GDP/million CNY	Total GDP/total population	Negative
		Average acre-foot water use for irrigated farmland/m3	Irrigation water use/irrigated acres of farmland	Negative
		Water consumption of 10,000 CNY of industrial output value/(m3/million CNY)	Industrial water consumption/million yuan of industrial output value	Negative
		Centralized urban wastewater treatment rate/%	Sewage treatment/total sewage discharge	Negative

Note: Positive attributes indicate that the larger the value of the evaluation index, the greater the sustainable utilization capacity of the basin’s water resources; negative attributes indicate a negative correlation between the evaluation index and the sustainable utilization capacity.

, which presents the Huangshui River Basin water resource sustainable utilization capacity evaluation index system.

(2)

Determination of criteria for grading fuzzy comprehensive evaluation indexes

In this study, the evaluation of the sustainable utilization capacity of water resources is categorized into five distinct levels to reflect varying degrees of sustainability, as follows:

Level I:

Low sustainable utilization capacity, indicating minimal sustainability in water resources’ use.

Level II:

Moderate sustainable utilization capacity, suggesting a balanced state of water resources’ use.

Level III:

Medium sustainable utilization capacity, denoting a fair level of sustainability in water resources’ management.

Level IV:

Strong sustainable utilization capacity, reflecting a high degree of sustainability and efficient water resources’ use.

Level V:

Very strong sustainable utilization capacity, representing an optimal state of sustainability and resources’ management.

The grading criteria for each evaluation index, which determine the classification into these levels, are detailed in

Table 2. Classification standard of evaluation index of sustainable utilization capacity of water resources in Huangshui Basin.

Objective	Criterion	Indicator	I	II	III	IV	V
Evaluation of sustainable utilization capacity of water resources	Indicators of climatic factors	Average multi-year precipitation/mm	<200	200~400	400~600	600~800	>800
		Concentration of precipitation/%	>80	70~80	60~70	50~60	<50
		aridity index	>7	3~7	2~3	1~2	<1
		Annual Precipitation Extreme Ratio	>3	2.5~3	2~2.5	1.5~2	<1.5
	Indicators for water resource systems	Water deficit/%	>70	50~70	30~50	10~30	<10
		Surface water resources’ development and utilization/%	>80	60~80	40~60	20~40	<20
		Ratio of inter-basin/regional transfers to local water resources/%	>20	15~20	10~15	5~10	<5
		Water quality compliance rate of water functional areas/%	<40	40~60	60~70	70~90	>90
	Socio-economic indicators	Water resources per capita/m3	<500	500~1000	1000~1700	1700~3000	>3000
		Water consumption of ten thousand CNY output value/(m3/million CNY)	>200	170~200	130~170	40~130	<40
		Population density /person/km2	>500	400~500	260~400	180~260	<180
		Per capita GDP/million CNY	>8	3.5~8	2.5~3.5	0.5~2.5	<0.5
		Average acre-foot water use for irrigated farmland/ m3	>400	320~400	260~320	200~260	<200
		Water consumption of 10,000 CNY of industrial output value/(m3/million CNY)	>100	66~100	40~66	18~40	<18
		Centralized urban wastewater treatment rate/%	<20	20~30	30~50	50~60	>60
Sustainable utilization capacity of indicators			Low sustainable utilization capacity	Lower sustainable utilization capacity	Medium sustainable utilization capacity	Higher sustainable utilization capacity	High sustainable utilization capacity

.

(3)

The evaluation model construction of the sustainable utilization capacity of fuzzy integrated water resources.

Let the number of evaluation indexes involved in the evaluation of the sustainable utilization capacity of water resources be one, there is an evaluation level, and the selected evaluation indexes of the sustainable utilization capacity of water resources are expressed in terms of the set of evaluation indexes established, as follows:

$$U=\left\{u_1,\cdots u_i,\cdots u_m\right\}$$

(1)

where, $u_i$ is the first evaluation index, $i=1,2,\cdots m$.

As can be seen from Table 2, the evaluation criteria for the sustainable utilization capacity of water resources in this study are divided into five levels, then the evaluation set established is the following:

$$V=\left\{v_1,v_2,v_3,v_4,v_5\right\}=\left\{\begin{array}{c}\mathrm{C}\mathrm{l}\mathrm{a}\mathrm{s}\mathrm{s}\mathrm{I},\mathrm{C}\mathrm{l}\mathrm{a}\mathrm{s}\mathrm{s}\mathrm{II},\\ \mathrm{C}\mathrm{l}\mathrm{a}\mathrm{s}\mathrm{s}\mathrm{III},\mathrm{C}\mathrm{l}\mathrm{a}\mathrm{s}\mathrm{s}\mathrm{IV},\mathrm{C}\mathrm{l}\mathrm{a}\mathrm{s}\mathrm{s}\mathrm{V}\end{array}\right\}$$

Let the degree of affiliation of the first water resource sustainable utilization capacity evaluation index to the evaluation set be recorded as the larger the value of the degree of affiliation, the greater the probability that the evaluation index belongs to the evaluation level [33]. This value can be solved by the following affiliation function calculation method:

$$r_{i,j=1}=\left\{\begin{array}{c}1,c_i<s_{i,1}\\ {\displaystyle \frac{s_{i,2}-c_i}{s_{i,2}-s_{i,1}}}\\ 0,c_i>s_{i,2}\end{array}\right.,s_{i,1}\le c_i\le s_{i,2}$$

(2)

$$r_{i,1<j<n}=\left\{\begin{array}{c}0,c_i<s_{i,j-1}or{c}_i>s_{i,j+1}\\ {\displaystyle \frac{c_i-s_{i,j-1}}{s_{i,j}-s_{i,j-1}}},s_{i,j-1}\le c_i\le s_{i,j}\\ {\displaystyle \frac{s_{i,j+1}-c_i}{s_{i,j+1}-s_{i,j}}},s_{i,j}\le c_i\le s_{i,j+1}\end{array}\right.$$

(3)

$$r_{i,j=n}=\left\{\begin{array}{c}0,c_i<s_{i,n-1}\\ {\displaystyle \frac{c_i-s_{i,n-1}}{s_{i,n}-s_{i,n-1}}}\\ 1,c_i>s_{i,n}\end{array}\right.,s_{i,n-1}\le c_i\le s_{i,n}$$

(4)

In the above Formulas (2)–(4): $r_{i,j=1},r_{i,1<j<n}$, $r_{i,j=n}$, respectively, for the first level (Class I), intermediate levels (Class II, Class III, Class IV), and the nth level (Class V) corresponding to the affiliation function; $c_i$ is the measured value of the ith evaluation indicator; and $s_{i,1},s_{i,2},s_{i,j-1},s_{i,j}$, $s_{i,j+1},s_{i,n-1},s_{i,n}$ are the evaluation level values of the 1st, 2nd, j − 1st, jth, j + 1st, n − 1st, and nth level of the water sustainable utilization capacity criterion corresponding to the first evaluation indicator. For the evaluation indices where the evaluation grade values are negatively correlated (inversely) with the classification standards, the reciprocal values of the evaluation grade values need to be calculated and substituted to transform the relationships of the evaluation grade values of all evaluation indices into positive correlations, namely $s_{i,1}\le s_{i,2}\le s_{i,j-1}\le s_{i,j}\le s_{i,j+1}\le s_{i,n-1}\le s_{i,n}$.

Based on the affiliation value $r_{i,j}$ calculated by the affiliation function, the fuzzy relationship matrix between the water resource sustainable utilization capacity evaluation indicators and the evaluation categories is established, which is denoted by $R$ as follows:

$$R=\left[\begin{array}{ccc}{r}_{\mathrm{1,1}}& \cdots & r_{1,n}\\ ⋮& r_{i,j}& ⋮\\ r_{m,1}& \cdots & r_{m,n}\end{array}\right]$$

(5)

(4)

Determine the Weights of Evaluation Indicators

Since the importance of each evaluation indicator of water resource sustainable utilization capacity is implicit in the grading criteria, the grading criteria values are used to determine the weights of the indicators, which are calculated using the following formula:

$$a_i={\displaystyle \frac{s_{i,n-1}/s_{i,1}}{{\sum }_{i=1}^m{s}_{i,n-1}/s_{i,1}}}$$

(6)

where $a_i$ is the weight of the first i evaluation indicator; n is the number of standardized scores; and $s_{i,1}$ and $s_{i,n-1}$ are the standardized values of the first evaluation indicator corresponding to level 1 and level n − 1, respectively.

Based on the calculated weight values, the weight vector can be obtained as $A=\left[a_1,\cdots a_i,\cdots a_m\right]$.

(5)

Establishment of a Fuzzy Comprehensive Evaluation Model

According to the fuzzy relationship matrix R and weight vector A, the fuzzy comprehensive evaluation model Y can be constructed as follows:

$$Y=A·R=\left[a_1,\cdots a_i,\cdots a_m\right]\left[\begin{array}{ccc}{r}_{\mathrm{1,1}}& \cdots & r_{1,n}\\ ⋮& r_{i,j}& ⋮\\ r_{m,1}& \cdots & r_{m,n}\end{array}\right]=\left[y_1,y_2,\cdots y_n\right]$$

(7)

According to the results obtained from the model Y in the above equation using the principle of maximum affiliation [34] to determine the comprehensive evaluation level, that is, $y_j=max\left[y_1,y_2,\cdots y_n\right]$, then the sustainable utilization capacity category of water resources of the evaluation object is the category j.

2.3.2. ELECTRE III Evaluation Method

ELECTRE (Elimination and Choice Expressing Reality) III is a Multi-Criteria Decision Analysis (MCDA) method that is primarily used to deal with complex decision problems, especially when there are multiple conflicting criteria. The method was proposed by Bernard Roy in the 1970s and belongs to the ELECTRE family of methods. The method introduces preference thresholds, no-difference thresholds, and rejection thresholds to characterize the decision maker’s sensitivity and tolerance to different criteria. The core of ELECTRE III is to determine the ranking of advantages and disadvantages by comprehensively evaluating multiple alternatives [35]. The specific steps to apply the method are as follows:

• Construct m evaluation objects and an n index judgment matrix. This paper has 5 evaluation objects and 15 indicators for the Huangshui River Basin based on the evaluation index system data series as a program with attribute values from A1 to A5, as follows:

$$R={\left(x_{ij}\right)}_{mn}\left(i=\mathrm{1,2},\dots ,m;j=\mathrm{1,2},\dots \right)$$

(8)

2.

The negative threshold is greater than the strict preference threshold. All the above three thresholds are determined by the decision maker and usually take a fixed value, and the veto threshold is usually three times the prioritization threshold. For any attribute j that satisfies v_j ≥ p_j ≥ q_j ≥ 0.

No difference threshold q_j:

$$q_j=0.3p_j$$

(9)

Strictly dominant thresholds p_j:

$$p_j={\displaystyle \frac{1}{m}}[a_{ijmax}-a_{ijmin}]$$

(10)

Veto threshold v_j:

$$v_j={mp}_j$$

(11)

where $a_{ijmax,}{a}_{ijmin}$ are the maximum and minimum values of the attribute values, respectively.

(1)

The formula for performing feasibility calculations is as follows [36]:

$$S\left(i,k\right)=\left\{\begin{array}{c}C\left(i,k\right),if\\ C\left(i,k\right)\prod {\displaystyle \frac{1-d_j\left(i,k\right)}{1-C\left(i,k\right)}},d_j\left(i,k\right)>C\left(i,k\right)\end{array}\right.$$

(12)

where the harmony index C(i,k) is the degree of a_i better than a_j on attribute k and d_j(i,k) is the degree of rejection of the a_j level higher than a_k on attribute k, which means that the program a_j is worse than the program a_k.

3. Results

3.1. Evaluation Index Analysis of a Single Index for Sustainable Utilization Capacity of Water Resources

The sustainable utilization capacity of water resources in the Huangshui River Basin, calculated from a multi-year data series, is detailed in

Table 3. Evaluation result of single indexes of sustainable utilization capacity of water resources in Huangshui River Basin.

Objective	Criterion	Indicator	Multi-Year Averages	Level
Evaluation of sustainable utilization capacity of water resources	Indicators of climatic factors	Average multi-year precipitation/mm	350	II
		Concentration of precipitation/%	84.2	I
		aridity index	2.57	III
		Annual Precipitation Extreme Ratio	5.3	I
	Indicators for water resource systems	Water deficit/%	34.4	III
		Surface water resources’ development and utilization/%	35.2	IV
		Ratio of inter-basin/regional transfers to local water resources/%	6.7	IV
		Water quality compliance rate of water functional areas/%	41.7	II
	Socio-economic indicators	Water resources per capita/m3	670	II
		Water consumption of ten thousand CNY output value/(m3/million CNY)	85	IV
		Population density /person/km2	196.5	IV
		Per capita GDP/million CNY	2.01	III
		Average acre-foot water use for irrigated farmland/m3	439	I
		Water consumption of 10,000 CNY of industrial output value/(m3/million CNY)	32	IV
		Centralized urban wastewater treatment rate/%	75	V

, which presents the average values and single index evaluation results. As illustrated in Table 3, the evaluation indices for rainfall concentration, the annual precipitation extreme ratio, and the average water consumption level per agricultural mu in the Huangshui River Basin all reached Level I, indicating a low sustainable utilization capacity. The indices for the multi-year average precipitation, water quality of water functional zones, and per capita water resources were categorized at Level II, suggesting a slightly higher but still low sustainable utilization capacity. Furthermore, the drought index, water shortage rate, and GDP per capita achieved a medium sustainable utilization capacity level.

These findings indicate that climatic factors and socio-economic conditions exert the most significant impacts on the sustainable utilization capacity of water resources in the Huangshui River Basin. Additionally, they highlight that there is room for improvement in the water resource system class index to enhance the overall sustainable utilization capacity.

3.2. Analysis of the Results of the Fuzzy Comprehensive Evaluation of the Sustainable Utilization Capacity of Water Resources

According to Table 2, the Huangshui Basin’s water resources’ sustainable utilization capacity evaluation index grading standard was applied to 15 evaluation index and 5 evaluation standard-grade values. Using the affiliation function Formulas (2)–(4) calculated to obtain the affiliation value, the establishment of the Huangshui Basin’s water resources’ sustainable utilization capacity evaluation index and evaluation category fuzzy relationship matrix resulted in the following:

$$\mathrm{R}=\left[\begin{array}{ccccc}0.25& 0.75& 0& 0& 0\\ 1& 0& 0& 0& 0\\ 0& 0.665& 0.335& 0& 0\\ 1& 0& 0& 0& 0\\ 0& 0.32& 0.68& 0& 0\\ 0& 0& 0.864& 0.136& 0\\ 0& 0& 0.507& 0.493& 0\\ 0.915& 0.085& 0& 0& 0\\ 0.66& 0.34& 0& 0& 0\\ 0& 0& 0.765& 0.235& 0\\ 0& 0& 0.273& 0.727& 0\\ 0& 0& 0.939& 0.061& 0\\ 1& 0& 0& 0& 0\\ 0& 0& 0.795& 0.205& 0\\ 0& 0& 0& 0& 1\end{array}\right]$$

According to Formula (6), the calculated weight value for the Huangshui Basin’s water resources’ sustainable utilization capacity evaluation index weight vector is:

$$\mathrm{A}=\left\{\begin{array}{c}0.0554, 0.0222, 0.0970, 0.0277,\\ 0.0970, 0.0554, 0.0554, 0.0312,\\ 0.0831, 0.0693, 0.0385, 0.2216,\\ 0.0277, 0.077, 0.0415\end{array}\right\}$$

Finally, according to Formula (7), the Huangshui Basin’s water resources’ sustainable utilization capacity fuzzy comprehensive evaluation model results were calculated for $Y=A·R=\left[0.175, 0.168, 0.507, 0.108, 0.042\right]$. According to the observed principle of maximum affiliation, the above fuzzy comprehensive evaluation result of the maximum affiliation of 0.507 belongs to the third level, so the Huangshui River Basin’s water resources’ sustainable utilization capacity has a medium sustainable utilization capacity.

Finally, the sustainable utilization capacity of the Huangshui Basin’s water resources was evaluated using a fuzzy comprehensive evaluation model $Y=A·R=\left[0.175, 0.168, 0.507, 0.108, 0.042\right]$, as calculated by Formula (7). According to the principle of maximum membership degree, the evaluation results indicate a maximum membership degree of 0.507. This value corresponds to the third level, signifying that the Huangshui River Basin’s water resources have a medium sustainable utilization capacity, classified as Level III.

3.3. Results of the ELECTRE III Method of Evaluating the Sustainable Utilization Capacity of Water Resources

In this study, the ELECTRE III method was employed to evaluate the sustainable utilization of water resources, establishing a total of five evaluation objects, as follows: the Huangshui Basin and four standard programs. The entropy weighting method and threshold values were applied to determine the formula for these evaluations. The relationships between the Huangshui Basin and the standard programs are illustrated in Figure 2. The resulting index weights and thresholds derived from this analysis are presented in

Table 4. Evaluation index weights and thresholds.

Indicator	Weights (wj)	Strictly Dominant Thresholds (pj)	No Difference Threshold (qj)	Veto Threshold (vj)
C1	0.0663	760	228	3800
C2	0.0751	−33.16	−9.948	−165.8
C3	0.0555	0.4	0.12	2
C4	0.0569	−0.44	−0.132	−2.2
C5	0.0585	4	1.2	20
C6	0.0612	−4	−1.2	−20
C7	0.0664	−1	−0.3	−5
C8	0.0805	82	24.6	410
C9	0.0802	2900	870	14,500
C10	0.0697	0	0	0
C11	0.0716	−80	−24	−400
C12	0.0551	1.1	0.33	5.5
C13	0.0723	−112.2	−33.66	−561
C14	0.0609	2	0.6	10
C15	0.0698	71	21.3	355

.

According to the formula, the five programs were sorted, and the results are presented in the table. The sorting of the evaluation objects based on the ELECTRE III method is as follows: Ae > Ag > Huangshui River Basin > Af > Ah. The B(a_i) result for the Huangshui River Basin is zero, placing it between the Ag and Af programs. This indicates that the sustainable utilization capacity of the Huangshui River Basin’s water resources is classified as Level III. This classification is consistent with the results from the fuzzy comprehensive evaluation, which also categorizes the capacity as medium sustainable utilization. See

Table 5. Evaluation index weights and thresholds for different programs.

Indicator	A1 (Huangshui Basin)	A2 (Ah)	A3 (Af)	A4 (Ag)	A5 (Ae)
B(ai)	0	−3	−1	1	3
Rank	3	5	4	2	1

.

4. Discussions

A comparison of the weighting results obtained from the fuzzy evaluation method and the ELECTRE III method revealed significant differences in the indices considered to have the greatest impacts on the sustainable utilization capacity of water resources (Figure 3). In the fuzzy evaluation method, the drought index (C3), water shortage rate (C5), per capita water resources (C9), and water consumption per ten thousand CNY of industrial output value (C14) were weighted highly, indicating their substantial influences on sustainability.

Conversely, the ELECTRE III method emphasized the importance of different indices, such as the precipitation concentration (C2), water quality compliance rate in water functional zones (C8), per capita water resources (C9), and population density (C11), in affecting the sustainable utilization capacity.

Integrating the findings from both methods, it is evident that certain indices—the precipitation concentration (C2), the degree of drought (C3), water scarcity rate (C5), compliance rate with water quality standards in water functional zones (C8), per capita water resources (C9), and water consumption in irrigated farmland (C13)—have pronounced impacts on the sustainable utilization capacity of water resources. These indices should be prioritized in future water resource management strategies to enhance sustainability.

When addressing the critical issues surrounding the sustainable utilization of water resources in the Huangshui Basin, it is essential to concentrate on a set of core indicators. These indicators not only reflect the current state of water resource management, but also foresee potential and challenges for future development. Based on a detailed analysis of these indicators, targeted measures and recommendations are proposed to ensure the long-term, stable, and efficient use of water resources in the Huangshui Basin.

Enhance External Water Resources’ Allocation: Given that climate factors are pivotal in determining water availability, the analysis indicates that the Huangshui Basin’s climate-related indicators for sustainable water use are generally lower than the overall evaluation suggests. This implies significant water scarcity, highlighting the need to augment external water sources to bolster the basin’s total water resources and enhance its sustainable utilization capacity. Initiatives such as accelerating water diversion projects, like diversion water from Datong to the Huangshui Basin and diversion water from the Yellow River to Xining, are recommended.

Strengthen Water Resources’ Management: Implementing flood early warning systems with automatic rainfall stations in key watersheds for real-time monitoring and constructing and maintaining efficient drainage networks, including pipes, collection ponds, and pumping stations, with regular inspections to ensure functionality, are recommended. Moreover, given the relatively low per capita water resources and irrigation efficiency in the basin, it is crucial to maximize water resources’ utilization efficiency.

Increase Comprehensive Water Body Remediation: The low water quality standard rate within the Huangshui Basin’s water function areas calls for clear management objectives and corresponding measures. Regular monitoring and evaluation are needed to uphold water quality standards. Additionally, managing pollution sources from industrial, agricultural, and domestic sectors can reduce pollutant discharges. Establishing a sewage licensing system will regulate pollutant discharges. Strengthening water ecological protection and implementing ecological restoration projects, such as wetland conservation and river restoration, will help to restore the natural purification capacity of water bodies.

5. Conclusions

This study utilized a dual method combining the fuzzy comprehensive evaluation and ELECTRE III methods to evaluate the sustainable utilization capacity of water resources in the Huangshui River Basin. The findings indicated that the basin’s sustainable water resource utilization capacity is classified as medium (Level III), influenced predominantly by climatic factors and socio-economic conditions. Specifically, the rainfall concentration, agricultural water consumption, and water quality compliance rates were highlighted as critical areas that require attention.

To improve the region‘s sustainable water use, recommendations include enhancing external water resources’ allocation, optimizing water management practices, and implementing comprehensive water remediation efforts. The evaluation methodology offers valuable insights for guiding future water resource policies and strategies aimed at promoting the sustainable development of the Huangshui River Basin.

6. Limitations Ans Future Prospects

In analyzing our article on the sustainable utilization of water resources in the Huangshui River Basin, while the study employs a dual method combining the fuzzy comprehensive evaluation and ELECTRE III methods, there are several limitations in the research, as follows:

(1)

Limited Data

The study mainly utilizes data from 2010 to 2018, which may not fully represent the current status of water resources’ sustainability. With ongoing changes in the climate and socio-economic development, the lack of more recent data might affect the accuracy and relevance of the evaluation results.

(2)

Methodological Limitations

Although the fuzzy comprehensive evaluation and ELECTRE III methods offer a comprehensive evaluation, they rely heavily on predetermined weights and thresholds, introducing a degree of subjectivity [36,37]. The use of different weight-setting methods could lead to different evaluation outcomes, affecting the robustness of policy recommendations. Moreover, the complexity of ELECTRE III may introduce calculation errors, especially in handling conflicting criteria.

(3)

Spatial and Temporal Scale Limitations

The research focuses on a macro-level evaluation of the Huangshui River Basin, without accounting for variations within different sub-regions. Different areas might have significant differences in climate conditions, socio-economic development, and water usage. The study does not explore seasonal variations or short-term extreme weather events, which could significantly impact water resources’ sustainability [38].

Furthermore, this research underscores the need for ongoing monitoring and adaptive management practices that respond to both climatic changes and socio-economic developments. Future studies could focus on smaller regional scales and longer-term data to provide a more granular understanding of the water sustainability challenges and solutions within the basin. It could also focus on incorporating more recent data, refining spatial and temporal analyses, addressing the subjectivity of methodological choices, and offering more concrete policy implementation strategies. This would lead to a more accurate and actionable evaluation of the sustainable utilization of water resources in the Huangshui River Basin.