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TheChah Nimeh reservoirs of Sistan is as one of the main water sources of Zabol City used for drinking, agriculture, industry and livestock purposes. This study aimed to determine the contribution of the natural and concentration factors of heavy metals such as Cd, Pb and Cu in sediment of Chah Nimeh of Sistan. The concentrations of heavy metals in surface sediments were studied in six stations during 2013. To determine the concentration of the heavy metals atomic absorption spectrometer (Contr AA 700) was used. Sequential extraction analysis  was applied based on the share of natural and concentration factor sources of heavy metals. Sequential extraction analysis showed that a considerable part of the Pb (63.67%), Cd (55.17%) and Cu (57.17%) were from natural sources. The highest concentrations of Cd and Pb were 0.81 and 5.57 mg kg^-1, respectively, obtained in station one and the maximum Cu concentration was observed in station five (37.8 mg kg^-1), while the lowest concentration of Cd, Pb and Cu were 0.34, 3.95 and 31.4 mg kg^-1, respectively.

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Iran is geographically located in the arid climate zone of the earth, which has caused a natural shortage of water in the country. In the past, Iranians have taken some measures such as constructing qanat, dams and reservoirs in most parts of the country to cope with water shortages. Over time, population growth and the expansion of agricultural, industrial and service activities have increased the need for water use. In addition to these issues, the unbalanced distribution of activities and population in the country has often turned the natural phenomenon of water scarcity into a human and managerial phenomenon of the water crisis, as a result of which double pressure is placed on water resources. In this situation, it can be imagined that the environment and natural ecosystems are the first victims of human interventions that have led to water cuts or severe reductions in their right to water and the water crisis brings all kinds of environmental crises. The present study using a descriptive-analytic method investigates the effects and consequences of the water crisis on the country's environment. The research shows examples of this situation in different parts of the country. In a way that the water crisis in various dimensions has destroyed the environment and natural ecosystems in the country and has left irreparable consequences.

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Introduction
Increasing demand on the one hand, and decreasing resources for various reasons on the other hand, have doubled the importance of providing, managing, and optimally using freshwater resources in arid countries. Iran has experienced water shortages because of geographical reasons since ancient times, and today it is facing with water shortages due to human reasons and improper management of water resources. The increasing complexity of the water shortages has led to the emergence of problems in recent years. All economic sectors of the country have been affected by the aforementioned problems, and agricultural activities are not as prosperous as they were in the past. From a social perspective, the spread of migration and dissatisfaction have been consequences of the intensification of water shortages.
Security and access to water resources has been a topic of land management and geographic spatial organizing in Iran. Access to water resources has been the first reason for geographical dispersion of the population in Iran. This research which has focused on the water shortage in Iran, tries to explain the hydropolitical nature of the country's water resources and the transformation of the challenge of water shortages into a crisis.

The research method
This research with an inductive approach using the strategy of geographical and documentary studies is descriptive-analytic and data gathering procedure is based on library findings. Also, valid indicators have been used to measure the state of resources.

Findings
Factors influencing the emergence of challenges can be divided into two groups: natural and human factors. The obvious form of climate change in Iran is the change in the pattern of precipitation. Decrease in precipitation, change in precipitation patterns, change in intensity and duration of precipitation, irregularity in precipitation, and increase in temperature are the most important outputs of climate change in the country. According to the findings, the increase in temperature and the decrease in precipitation in the coming years will lead to a decrease in available fresh water resources.
Annual total rainfall, surface and groundwater inflow and outflow to the country is 400.8 billion cubic meters. Of the total 100 percent of rainfall, 60 percent is lost through direct evaporation. Another 11 percent is lost through forests, pastures, and rainfed areas. Thus, more than 70 percent of the water received is quickly lost through evaporation and transpiration before entering the consumption cycle. The remaining water volume for the country is about 130 billion cubic meters and in fact constitutes the country's water potential.
Climate change has had a significant impact on precipitation systems, and in addition to creating temporal irregularity, it has also exacerbated spatial irregularity. Iran is among the nine countries most vulnerable to climate change. Changing precipitation patterns is one of the most obvious consequences of climate change worldwide. A prominent form of climate change in Iran is also the change in precipitation patterns. Decreased precipitation, changing precipitation patterns, changes in the intensity and duration of precipitation, irregularity in the timing of precipitation, and increased temperature are the most important outcomes of climate change in the country.
The country's resources are managed by the Ministry of Energy, but the most important water consumer is the Ministry of Agricultural Jihad. Department of Environment is responsible for monitoring and supervising water resources to ensure water purity. Multiple and separate policies have led to the failure to achieve integrated water resource management and the failure to integrate water policies has led to a diversity of water strategies.
One of the most important challenges facing the country's water resources is the excessive exploitation of these resources. This exploitation has reached such a level that the capacity for aquifer restoration has been destroyed and a negative balance has become a common feature of all aquifers. The limited availability of groundwater resources, the imbalance in the groundwater balance, the lack of permanent rivers, and the subsequent weakness of groundwater aquifer recharge have exacerbated these limitations in recent years.
Inter-basin water transfer, plain subsidence, and insecurity caused by water shortages are consequences of improper management of the country's water resources. One of the most important challenges of the country's water resources is the excessive exploitation of these resources. Water shortage has aggravated the imbalance in the underground water balance, the lack of permanent rivers and then the weakness of feeding the underground water reservoirs.
According to the surveys conducted and the statistics and information of the synoptic stations and the Ministry of Energy, in the last 15 years, the temperature of the Iran has increased by about 1 degree Celsius. Also, the country's rainfall has decreased by about 15% in this period compared to the long-term period. Over exploitation and decrease in rainfall have caused the number of prohibited plains increase from 15 plains in 1968 to 405 plains in 2017.

Conclusion
The findings of this research indicate that mismanagement on the one hand and climate changes from the other hand are turning the water shortage problem into a water shortage crisis in Iran. The assessment of Iran's water resources situation in the form of indicators also emphasizes that it is on the brink of a water shortage crisis.
Over exploitation has caused a deficit of 5 billion cubic meters per year, and as a result, the level of underground water has dropped. Exploitation of rivers flow has exceeded the permitted level and the rivers of the country have been prevented from their usual and natural flow. The phenomenon of water scarcity will lead to unemployment, widespread migration, protests, subsidence of plains, excessive land dryness, increased dust production, disruption of urban and rural life, loss of plant and animal ecosystems, etc. The results of the continuation of the current trend of the country's water resources are a growing linear situation with expanding dimensions.

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Data and information play a special role in the transparency of water governance. On the other hand, witnessing contradictions in water resources data and information, inconsistent readings and narratives about water assets, outdated hardware equipment, and to some extent software enhancement in the preparation and presentation of water resources information compared to global advances, necessitates a serious review of water resources data collection and processing systems. In this regard, artificial intelligence methods, sensors, and remote sensing technologies are considered in accurate water resources accounting. This article is a systematic review of about 100 international articles that present the latest findings related to software and hardware equipment for monitoring hydrological cycle meta-indicators. These meta-indicators include precipitation, water depth/water level/flow velocity and discharge of rivers, and groundwater level. In each case, while providing a list of the most important technologies, the application level of these technologies in monitoring surface and groundwater resources in Iran was evaluated. The conducted studies prove the unfavorable application technologies in monitoring hydrological cycle in Iran. For example, out of a total of twenty-six known technologies related to surface flow measurements, only two technologies have been widely used Iran; four technologies have reached the knowledge frontier and widespread production by domestic knowledge-based companies, and eleven technologies have not yet reached the knowledge frontier Iran. In this paper, suggestions were presented to outline the path for developing new technologies for water cycle data collection and transformation in the modernization of Iran's water resources data collection and data processing infrastructure.

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Water deficiency and incorrect management of available water resources caused water crisis and drought occurrence increased intensity of the crisis. These crises have environmental, economical and social aspects. In this research, water crisis of Nishabor was studied. Thus, climatic, hydrologic, geologic and land use data layers were used and based on these data, analysis of the plain aquifer, hydrologic water balance, water needed and land use role on water crisis and finally spatial distribution of water crisis took places. The obtained results indicated that Nishabor aquifer storage has water deficiency of about 200 million cubic meters and the areas with medium to high water crises cover about 50 percent of study plain. Considering the exciting land use, we proposed land use correction for the areas with crises in order to manage and controlthe intensity of water crises.

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In recent decades, due to water crisis, most countries have been more interested in new policies for managing water demand instead of regulating the water supply. In dry and semi-dry areas of Iran such as Fars province, water scarcity is not only the important factor that impedes economic development but also special input in production. Drought in year 2007 could be considered as a risk of crisis in water supply. So, the purpose of this study is managing water demand through economizing surface water and groundwater resources which is of special importance in the region. It is self-evident that agricultural economy has a close relationship with water management. In this research the standard Positive Mathematical Programming (PMP) method is used to calibrate the agricultural sector model. A two-stage stratified random sampling through personal interviews of Bakan from Eghlid farmers has been applied, where abundant water resources and groundwater exist. By selecting a real sample of farms, model calculation for both areas is carried out. Two scenarios are identified. In the first scenario, by using PMP model for each group from water resources are calculated separately. They differ in terms of net revenue which is because of overly cost of construction and operation of wells between the two groups of surface water and groundwater. Results show that 10% decrease in water supply or doubling the prices will not change the optimal crop pattern in comparison to the base pattern. The results of model calculation shows that through running new irrigation methods (intensive irrigation) and also by effective pricing policies, investment can be encouraged in the water sector and in the area and therefore, through optimum management of water demand the water resources can be saved and any form of waste avoided.

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In the recent decades, water demand has been increased specially in arid and semi-arid areas, led to the over-exploitation of water resources. Groundwater resources are important sources of water supply for domestic, industrial and agricultural consumption. Nowadays, over-exploitation from groundwater resources has increased the pressure on these sources which causes the major environmental damages. In this study, a cooperative game theory model is used to investigate how the cooperation of groundwater resources consumers influences the environmental damage and the benefit of stakeholders. The used model in the present study is developed for investigation of an optimal control problem including the variables of economic, environmental, agronomic, and hydrologic issues. Ant colony optimization method is used to flexible define and solve the simulation-optimization problem of this study which provides an ability to consider an extensive range of objectives and constraints. The results show that how uncontrolled pumping and over-exploitation in each aquifer affect on the stakeholders of the adjacent aquifers. Furthermore, the impacts on aquatic ecosystems are analyzed and presented as environmental damages. The obtained results demonstrate that in different areas, environmental damages are reduced under the coalition and effective cooperation condition among stakeholders and considering the environmental externalities in comparison with status quo. In the recent decades, water demand has been increased specially in arid and semi-arid areas, led to the over-exploitation of water resources. Groundwater resources are important sources of water supply for domestic, industrial and agricultural consumption. Nowadays, over-exploitation from groundwater resources has increased the pressure on these sources which causes the major environmental damages. In this study, a cooperative game theory model is used to investigate how the cooperation of groundwater resources consumers influences the environmental damage and the benefit of stakeholders. The used model in the present study is developed for investigation of an optimal control problem including the variables of economic, environmental, agronomic, and hydrologic issues. Ant colony optimization method is used to flexible define and solve the simulation-optimization problem of this study which provides an ability to consider an extensive range of objectives and constraints. The results show that how uncontrolled pumping and over-exploitation in each aquifer affect on the stakeholders of the adjacent aquifers. Furthermore, the impacts on aquatic ecosystems are analyzed and presented as environmental damages. The obtained results demonstrate that in different areas, environmental damages are reduced under the coalition and effective cooperation condition among stakeholders and considering the environmental externalities in comparison with status quo. In the recent decades, water demand has been increased specially in arid and semi-arid areas, led to the over-exploitation of water resources. Groundwater resources are important sources of water supply for domestic, industrial and agricultural consumption. Nowadays, over-exploitation from groundwater resources has increased the pressure on these sources which causes the major environmental damages. In this study, a cooperative game theory model is used to investigate how the cooperation of groundwater resources consumers influences the environmental damage and the benefit of stakeholders. The used model in the present study is developed for investigation of an optimal control problem including the variables of economic, environmental, agronomic, and hydrologic issues. Ant colony optimization method is used to flexible define and solve the simulation-optimization problem of this study which provides an ability to consider an extensive range of objectives and constraints. The results show that how uncontrolled pumping and over-exploitation in each aquifer affect on the stakeholders of the adjacent aquifers. Furthermore, the impacts on aquatic ecosystems are analyzed and presented as environmental damages. The obtained results demonstrate that in different areas, environmental damages are reduced under the coalition and effective cooperation condition among stakeholders and considering the environmental externalities in comparison with status quo.

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There is a growing demand for solving conflicts among water users and stakeholders under climate change conditions. This study applied ten CMIP5 climate models under the RCP8.5 scenario to simulate Doiraj Reservoir water allocation in Ilam Province. To reduce the uncertainty of climate models, the MOTP method was used by combining different GCM models. To predict reservoir inflow, the IHACRES Rainfall-Runoff model was considered and validated for the 2016 to 2044 time periods. Climate and hydrological indicators were extracted to monitor drought periods in the current and future projections. The WEAP model and the Asymmetric NASH Bargaining Method were used to simulate the water basin system and solve the conflict between stakeholders based on their utility functions, respectively. The results indicated that the rainfall would increase by 17.1 and 11.1% in spring and autumn and decrease by 9.4% in winter in the future projection. Furthermore, the highest temperature and runoff growth rate increased by 1.95°C in September and 6.3% compared to the base period, while demands would be increased by 55.75%. The long-term agricultural deficit are obtained as 10.9 and 10.2% by the WEAP model in the current and future conditions. Finally, the duration curve of reservoir storage showed that 20% of the time, the reservoir storage is empty for the Standard Operation Policy (SOP). By switching to the Nash bargaining policy, not only the minimum storage capacity reached 18 MCM for all the time, but also the effects of climate change would be adapted in the future, and the utility functions of all stakeholders would be satisfied as well.