عنوان مقاله [English]
Water can be considered as one of the most important factors of growth and economic development of each country. The lack of water resources and low efficiency of methods of operation in the country has made the country to use excessive groundwater resources and have environmental problems in Iran. In this study, environmental efficiency of water resources across the country in order to evaluate the efficiency of the variable - based model (slack - based) model on relaxation was considered. Then, in this study, using the dynamic panel model with the application of the generalized moments of space in 2011 - 2018 in 31 provinces, the effect of threshold extraction of water resources was studied. The results of the overall efficiency of the first stage were significantly higher than the performance of water resources in the second stage and the overall efficiency was close to the effectiveness of the second stage and the efficiency of the second stage determined the overall effectiveness of the environmental efficiency of Isfahan, Kerman, Semnan, North Khorasan, South Khorasan, Razavi Khorasan, and Yazd. The SAR space variable had a coefficient 0.142, which indicated that the efficiency of water resources across the provinces, where the geography location was independent of political divisions, had spatial effects on the real GDP of the neighboring provinces. overall efficiency of water resources had sudden spatial effects and the overall efficiency of regions was affected by neighborhood regions. Direct and indirect effects of internal water consumption, opening degree and industrial structure had meaningful effect on the overall efficiency of water resources in Iran. The spatial effects of internal water consumption and industrial structure had a significant effect. In order to improve the efficiency of water resources, the government, citizens and farmers should focus on solutions such as reducing pollution, saving domestic water and converting industrial structures. It was suggested that in the lower - efficiency oblasts with less efficiency in order to improve efficiency, production structures and technologies with the use of more efficient water resources rather than destructive and polluting technologies, the government controled and improved the efficiency of the country 's water consumption by implementing strict laws to protect the country 's water resources.
Today, water shortages are the biggest problem in the world, and the crises caused by the lack of freshwater resources pose a serious threat to sustainable development, the environment, health and well - being of human beings, so that it forces governments to change how to deal with these resources and include collaborative management practices in all stages and levels of water and environmental management (Zhao et al., 2017). However, water shortages and water quality problems have increased in Iran in recent decades (Norouzian, et al 2021) The indirect distribution of water resources reduces limited access to water. Iran 's water resources are currently facing pollution and environmental (Kurd 2018). Nowadays, humans face many problems in the development process to supply water. This situation in arid climates, where ecosystems involved in water supply is more fragile and makes critical problems with drought and excessive removal of water reservoirs with more critical conditions. The limitations of water resources, rapid population growth and the need for more production have caused the agricultural sector to demand more for consumption, so the most important challenges of the agricultural sector in these regions are less likely to produce more food than water (Saghafi, 2016). Considering the limitations of water resources available in the country and increasing demand for different water consumption in all its aspects and thus reaching the critical boundary using water resources, renewable water resources are required to provide water security, codified rules on this basis for balancing water consumption and water supply. managers ' knowledge of available water resources and generally all the relevant categories of different methods of demand management decisions and especially the determination and estimation of effective factors are considered as the most essential items in water management (Ansari et al., 2017).
in this study, the efficiency of the water resources of the provinces is estimated using the model (SBM) and then has been examined using the Spatial Durbin model (SDM) the effect of effective economic factors and water consumption in different sectors. Based on the non - linear measurement model and the deficit variable (slack - based), the undesirable output proposed by (Tone, 2003) is considered to be efficient compared to fixed - scale. Undesired production system model is based on a lack of slack - based measurements and production facilities (Zhao et al., 2017).
Spatial Econometric Models
The spatia econometric is the branch of the econometric that considers the spatial effects. The spatial effects are more than that of the factors related to the location of the variables and can be explained in terms of spatial dependence, spatial correlation, spatial differentiation, or spatial structure. It is similar to econometric with geographic statistics and spatial statistics, but the spatial econometric difference with them is just the same as the econometric difference (Anslin, 1995). in general, the spatial model of the spatial regression consists of the general pattern of the spatial regression (SAC), the spatial pattern of the regression (SAR), the regression model with spatial autocorrelation, such as the disturbances (SEM) and the Spatial Durbin model (SDM), (Salami and Nemati ,2012). To estimate the effective factors on water resources efficiency in Iranian provinces, the spatial econometric approach has been used. on this basis, the models of spatial regression, spatial error, spatial camera model and the general spatial model are estimated and finally the final optimal model is selected. In order to determine the indirect effects of the spillway, the spatial camera model has been studied and the effects of the variable spillway efficiency are estimated in the provinces of Iran. The spatial econometric models, as indicated, are included 4 kinds, that are briefly described. Among the spatial econometric models, the spatial error model (SEM) is not possible to measure the effects of the regional spillover (Vega and Alorest, 2013; Carachoca and Catic 2011). The spatial camera model and the general model show the results of the effects of the spillway effects (spatial)strain (Zaranejad and Mansuri, 2015). In order to determine the most appropriate model, it is necessary to take these steps. At first the regressions of the estimated spatial econometric models are estimated, then the Moran 's test to determine the spatial effects must be confirmed and Based on LM statistics (Florax et al 2003) from the spatial econometric models (SAR, SEM, SDM, SAC) the optimum model is chosen. At the end the direct and indirect effects (spillover) are estimated. According to literature, spatial models are considered as follows (Alorest, 2015).
in this study, environmental efficiency of water resources across the country in order to evaluate the efficiency of the variable - based model (slack - based) model on relaxation was considered. Then, in this study, using the dynamic dynamic panel model with the application of the generalized moments of space in 2011 - 2018 in 31 provinces, the effect of threshold extraction of water resources was studied. The results showed that from 2011 to 2018 the total energy efficiency of regional water resources in the provinces of Iran was significantly different and spatial distribution was very unequal. However, the efficiency of Kerman, Semnan, Northern Khorasan, South khorasan, Khorasan, and Yazd is deteriorating. From 2011 to 2018 the environmental productivity of water resources in the second stage showed that the growing trend in recent years was declining. Using the two - step production process with respect to the undesirable output, the two - stage relationship analysis between production of water pollutants and disposal in this study showed that the second stage of disposal of water pollution affects the overall efficiency of the system. Currently, the water crisis in the country has resulted in excessive demand for water resources due to widespread use of water. This pattern of exploitation will have serious effects on the environment. The implementation of environmental regulations must change the patterns of water use and strengthen protection of water. To increase the total water efficiency in these systems, the country has to significantly facilitate recycling and reuse of sewage in production processes. Moreover, it is necessary to strengthen the management of industrial wastewater treatment. It is essential to strengthen oversight and inspection of large - scale pollution production companies to meet water depletion standards. The results of this study correspond to the study by Zhao et al (2017). The efficiency of regional water resources in the whole region has significant spatial differences: higher productivity regions mainly along the North and North West of Iran are higher productivity than East and Southwest of Iran. Each region needs regional co - operation and communication with its own conditions to gradually change the efficiency of regional water resources from the lowest to the highest.