Groundwater resources over-exploitation in Iran leads to a reduction in the volume of water stored in aquifers, reduction in groundwater quality, the striking the especially in the desert and coastal aquifers, saltwater fronts, subsidence, seams, cracks, sinkhole, damage to infrastructure facilities and in important plains of the country and an increase in the deepening and moving the wells. Consequently, under the influence of the condensation of the aquifers and the destruction of the porosity, even in case of rainfall, there is no possibility for water penetration and storage in the aquifers. The total level of Iran is grouped into 609 study areas concerning the catchment area. According to the Water Resources Management (WRM) organization, a sharp decline in groundwater levels and the aquifers’ reservoir deficit resulted in banning the 420 of the above 609 regions based on rules to expand the exploitation of groundwater resources [1].

The ABM approach is an appropriate tool for modeling complex systems and phenomena in which the behavior of people or institutions is significant. In this modeling approach are modeled the actors (agents) and their behaviors concerning themselves and their environment. They are used to measure the effectiveness of the behavior of different actors in the system and their interaction with their environment on the overall behavior of the system. The potential features of the ABM approach for facilitating the participation process and improving its quality were of utmost discussion in the water resources management in recent years [2].

ABM approaches, by use of simulating the consequences of people’s behavior, can be considered as a remarkable help in the conventional analytical approaches for investigating environmental problems [3] and presenting the visual framework for studying social and ecological variables [4]. Considering two social and ecological dimensions or the users and the water resources system, this model makes it possible to deal with water resources management issues with more realistic and take action in stabilizing water resources. In ABMs, the participation of authorities is regarded as a vital element [5]. The bottom- up approach applied by ABM was critical in investigating the socio-environmental systems [6, 7]. This computational model was used for simulation and adopted from the research fields of artificial intelligence and cellular automata [8].

However, the interaction between environmental and social variables in the ABM might be greatly simplified [9]. The interaction between agents was usually considered based on time and environmental and social variables [10]. A combination of social and natural science methods was needed to properly study the dynamics of social and environmental subsystems and examine environmental and social variables [11, 12]. A comprehensive study of the complexity of environmental, social, and economic systems might be required an interdisciplinary approach [13]. Many studies were conducted on the relationship between physical models of environmental systems and simulations based on social process factors. Some of those studies were conducted by [14, 15].

ABM techniques had a person-centered approach in which each user had their own behavioral rules. Each user could make a change in the behavior regarding the information received from other users and the environment. Moreover, users did not need to share the whole information with others [16]. The limitation of the ABM model was that its forecast was always conditional, depending on the conditions set forth in the model. In [17] allowed the possibility of decision-making concerning dynamic behaviors of agents interacting with each other and their environment [18, 19]. The ABM was able to simulate the human decision-making process by specifying the behavior of the agents.

The ABM is a decision-making support tool and could offer water resources protection measures by various scenarios and assumptions [20]. The application of ABM approach in the water resources management was begun from one decade ago and became a popular topic in the analysis of natural-human systems [21, 22, 23, 24, 25, 26, 27, 28, 29, 30].

The opinions should be cautiously designed to increase the value-added result using ABM in land and water management [31]. The ABM was applied to forecast the urbane household water demand in Beijing in 2020 [32]. Furthermore, this model simulated urban water dynamics [33]. Nouri [34] attempted to simulate the rules of the system in the form of mathematical relations concerning the interaction between agents such as the environment and agriculture.

The ABM approach was observed in the different areas such as archeology, biology, economics, environment, electricity market analysis, financial analysis, social sciences, transportation system and water management system [35, 36, 37].

Lately, ABM models were offered as a proper factor in terms of describing the processes of using innovation in the area of energy and electronic resources [38, 39] and known as a popular tool in the scientific community to manage the problems raised by the natural human system [40].

ABM models were taken into consideration as a powerful tool for modeling complex systems [41]. Applying this approach facilitated the consideration of two general social and ecological sectors as well as their mutual influences. The social sector in this approach encompassed all users or actors who were under the influence of the system and also affected the system. The ecological sector in this approach consisted of all of the sub-models that formed water resources and their related systems. Nothing limited the definition of the social and ecological sector and the relationships between them in the modeling approaches. The only weakness and restrictions were observed in the data and field information. The most remarkable strength of this modeling approach was observing the social sector in the model along with ecological sector as well as regarding their relations and interactions [42]. Actually, the principal idea of this approach was to close the model to the real situation of the problem as much as possible and consequently obtain more realistic results from the model. This was way the use of ABM modeling was significantly increased in the field of modeling the complex systems, especially complex water resources systems [21].

ABM modeling and its use in water resource systems between them and the environment and the communications of the set of agents located in it formed the components of an ABM. Moreover, agents interacted with their environment [36]. Then, it was possible to illustrate individuals, organizations, and their activity environments as multi-agent systems (MAS) and utilize ABM approach.

The unsuitable condition of groundwater resources in Iran, resulted by incorrect management, excessive aquifer withdrawal in Iran and successive droughts, led to numerous problems including subsidence, water salinization, increasing the depth of water table and consequently increasing the required energy consumption for water extraction and social consequences such as forced migration from motherland and suburbs in large cities. Different strategies were proposed by the authorities to therapy this matter, but it must be in such a way to entail maximum effectiveness and have minimum consequences. The ABM was a modern model considered for problem-solving, used in examining the proposed scenarios by observing all limitations and weaknesses and strengths. Through ABM, it could be select the best scenario to solve the problem of groundwater. This study selected Qazvin plain as a pilot, which was located in central regions of Iran, and its agriculture was highly dependent on groundwater resources.

Using the ABM was increasing for modeling different systems, especially complex socio-ecological systems of water resources. Since the agricultural sector was known as the largest consumer of surface and groundwater resources, the collection of farmers and their withdrawal of water resources were highly remarked in the conducted papers. To this end, were developed some models in order to contribute the decision-makers and users in making better decisions on their policies and cultivation patterns, profitability, resource exploitation, and sustainability. The adaptable policies in the water resources systems were categorized into three different groups [43]. The first group was technical tools to control water consumption. The use or development of the use of modern irrigation systems as well as installing the flow-meters on agricultural wells and their application were among the policies of the first group. The second group encompassed economic tools. Water pricing, tax, withdrawal fines, and the water market were among the policies embedded in the second category [26]. Finally, the third category dealt with non-economic policies, such as rules of access to water, water quotas and exploitation training [26, 44, 45, 46].

However, all policies apparently could be conductive in controlling the extraction and stabilization of water resources. In reality, there might be no necessary sanction for all of them due to the significant effect of the social sector or the users. Often, the characteristics and behaviors of water resources exploiters were in such a way that some policies would not meet their expectations. Then, these policies did not signify the sustainability of resources and also led to the destruction of water resources. It could be possible to detect the superior policies in the field of water resource management through ABM with more realism and under the conditions of the study area. For example, Feuillette [43], using their developed ABM, concluded that the condition in the area under the study was in a manner that not only subsidizing farmers for changing the irrigation system did not reduce the water resources withdrawal, but also provided the condition for cultivating more lands and hence more exploitation of water resources. Doubtlessly, the most challenging part of ABM was related to the designing part of agent behaviors. Certainly, the best kind of validation could be a combination of quantitative and qualitative methods [42].

The study area was Qazvin with 7347 km² and located in the longitude of 80'and 49'to 41 and 59 degrees east and latitude of 19'and 35'to 30 and 36 degrees north in Qazvin province. Figure 1 revealed the location of Qazvin study area. The value of groundwater withdrawal, from 8471 wells, was equal to 1,74×10⁹ m³/yr (1,74 billion m. per year), 95 % of which was through agricultural wells. The status of unauthorized and authorize wells in that plain was presented in Table 1. The annual reservoir deficit of Qazvin plain in 2020 was about 160 billion m³. The cumulative reservoir deficit of this aquifer was about 8663 billion m³. The volume of excessive withdrawal of authorize wells and the depletion volume of unauthorized wells was 983,37 billion m³, 514,55 billion m³, respectively, and total depletion volume from the aquifer was equal to 1497,92 billion m³.

Figure 1 Figure 1 Qazvin study area location map

The main disruptive factors in the balance between income and outcome agents of aquifers were depletion of aquifers by unauthorized wells and excessive withdrawal by wells with exploitation license, so-called overdraw.

Table 1 Table 1 Status of exploitation wells in Qazvin plain [1]

The mean of annual reservoir volume deficit and cumulative reservoir volume deficit of the mentioned plain from 1995 to 2019 was 160 billion m³ and 8663 billion m³, respectively.

Figure 2 exhibited the hydrograph of Qazvin plain. Obviously, in this hydrograph, the water table of Qazvin aquifer was diminished by 31 m from 1995 to 2019, which was declined on an average of 1 m annually. As observed in this diagram, the current meter installation process, started from 2015, had not a significant effect on improving the status of the water table drop, and it was required to take a step in tackling the existing situation.

Figure 2 Figure 2 Qazvin plain hydrograph 1

Table 2 was subjected to types of products that were mostly cultivated in the area and the area and percentage of cultivation of each product. As it was cleared, the majority of agricultural items were wheat, alfalfa, and corn, and most of the garden items were grapes, pistachios, and walnuts.

Table 2 Table 2 Combination of agricultural products cultivation in Qazvin plain

In Table 3, 5 scenarios were observed, aiming at preventing unauthorized exploitation, increasing irrigation efficiency, receiving water price and overdraw fines, increasing the purchase price of products, and reducing the depletion of unauthorized wells. The output of the ABM for each of the above scenarios was presented in Figure 5.

Figure 5 Figure 5 Output parameters variations Total annual extraction in different scenarios

Annual reservoir deficit and cumulative reservoir deficit of Qazvin plain were equal to 160 billion m³ and 8663 billion m³, respectively. The objective of implementing these scenarios was to drop the annual reservoir deficit to zero in the short term (maximum 5 years) and to compensate for the cumulative reservoir deficit in the long term (20 years). It was attempted in all scenarios to prevent the unauthorized withdrawal in the first five years, to make the aquifer balancing process more meaningful. As observed in Figure 5, the deficit of wells depletion was reduced during the first 5 years by 514 billion m³ after implementing scenario 1.

This was due to the filling the unauthorized wells and the prevention of overdraw of authorize wells. Then, due to the implementation of pressurized irrigation, the efficiency of irrigation would be enhanced. Still, the depletion volume would be constant due to the development of the area under cultivation. On the other hand, due to the reopening of some unauthorized wells and boring of new unauthorized well, groundwater depletion would increase again. Through interaction strategy and non-prevention of unauthorized withdrawals, which had many social consequences and caused farmers and their families to protest, scenario 2 tended to manage withdrawal of wells by increasing the irrigation efficiency and guaranteed purchase price, but this measure was not hopeful. In the beginning, although it had a slight decrease in the withdrawal, it was continued and resulted in overdraw.

In Scenario 3, at first unauthorized withdrawals were removed, and then, if they did not reach the balancing point, the volume required to comply with the withdrawal limit was decreased from the authorize wells. In this scenario, the depletion of wells was reduced about 549 billion m³ about 5 years after the start of the plan, but then this value was minimized to 159 billion m³ to reach the authorize depletion. In this scenario, although the aim of the plan could be met and the deletion of wells could be dropped to the permissible level, it would give rise to unbearable pressure on farmers and caused a lot of resistance. In scenario 4, all measures were observed except for mitigating the withdrawal of authorize wells. In this scenario, there would never be a balance due to unauthorized depletion but would entail relative satisfaction of the exploiters. In Scenario 5, all measures were performed simultaneously. In this scenario, despite the elimination of unauthorized withdrawals to achieve balance, some of the authorize withdrawals were diminished. Still, a portion of farmers’ losses was compensated by increasing irrigation efficiency and the purchase price of the products.

Figure 6 displayed the total saved volume by implementing each scenario. Maximum savings were observed in the implementation of scenario 5, and an increase in the withdrawal volume from the aquifer was a result of scenario 2.

Figure 6 Figure 6 Total cumulative extraction; in different scenarios

The output of Figure 7 exhibited that the farmers’ revenue reduced due to the implementation of scenarios 3, 4 and 5 in proportion to the volume of withdrawal mitigation from the aquifer. After the implementation of scenario 1, farmers’ incomes reduced as the unauthorized withdrawal was prevented for 5 years. But, their revenue increased again due to an increase in irrigation efficiency and the development of the area under cultivation. With respect to non-prevented unauthorized withdrawal in scenario 2, it was observed that the farmers’ revenue was slightly minimized due to imposing fines for unauthorized withdrawal and increasing water price during the first few years. However, their revenue was next increased due to an increase in efficiency and also an increase in the guaranteed purchase price.

Figure 7 Figure 7 Output total annual net revenue variations in different scenarios

To review the impact of the implementation of scenarios on groundwater status, it was studied and compared again 5, 10, and 20 years after implementing the plan in different scenarios. Figure 8 indicated that the height of the water table was increased, and the deficit of the aquifer reservoir was compensated by implementing the best scenarios from a to c.

Figure 8 Figure 8 Changes in the iso-piez map of the study area in two and three-dimensional forms. Images from a to c indicated the effect of reduced groundwater depletion on the region’s iso-piez map

This paper utilized ABM as a method to survey the effective solutions for resolving the groundwater crisis in the Qazvin plain. According to the intended strategies and implemented scenarios, it was tried to prevent an overdraw of authorize wells, which was conducted by installing a smart volumetric meter. This prevention was the most noticeable and effective project in controlling the extraction of groundwater resources. Regarding that there were three important and basic factors in the implementation of this project such as the government (ministry of energy and the ministry of agriculture) and the people (farmers) and the environment and the physical and hydrogeological conditions of the region affected by their performance, the ABM was an efficient and practical method for problem-solving and selecting the best scenario for removing existing challenges and performing a project.

The filling unauthorized wells was significantly emerged in reducing aquifers withdrawal. However, since these two measures would reduce farmers’ revenue, a lot of resistance would be created against their takings. Hence, it was required to be conductive in compensating the reduced revenue of farmers by applying the compensatory methods such as increasing irrigation efficiency and implementing new irrigation methods and also increasing the guaranteed purchase price. On the interviews with farmers and government representatives and the prepared questionnaires for this purpose, and the obtained results from the implementation of the model, it was inferred that presenting all-inclusive cooperation was suggested to achieve the goals of the plan and reduce withdrawals from the region’s aquifers and consequently reach the balanced aquifer.

The interests of all agents should be clear in the measures, and then unilateral actions would not be satisfactory. Since the farmers were affected by each other, it was so vital to creating conditions in which farmers competed positively for maintaining the aquifer of the plain and stop attempting in more exploitation and achieving an optimum result. In the following, it was recommended to study the effectiveness of other methods on the improvements of the condition of the aquifer such as artificial recharge and watershed management by making use of ABM approach, and then to take action based on results in decision-making on the manner of implementation of each project in different study areas of the country.

We, as researchers, would like to extend our gratitude to all those, especially Iran Water Resources Management (WRM) Company and the Qazvin Regional Water Company, who assisted us in conducting this research and the farmers and experts in the region who cooperated with us and provided the required information.