Surface water and groundwater interactions can occur between surface water bodies (such as rivers, lakes, and wetlands) and groundwater resources. Quantifying water exchange between a wetland and an underlying aquifer is an important task for studies in such fields as water budgets and environmental water requirements. In this study, the groundwater component from controlling factors on wetland water level is considered to determine the water requirements of Kaniborazan wetland, located at the southern part of Urmia Lake. The results of the present study indicate that during the assessment period of 1998-2015, Kaniborazan wetland has been always recharged from underlying groundwater resources considering the hydraulic gradient threshold of this wetland. These recharge values have been maximum for 1998, 2002, and 2015 with the annual value of 4. 11, 5. 09, and 3. 78 MCM, respectively. The mean annual value of this wetland depth has been estimated to be less than 16 cm. The impacts of drainage system, channels, and traditional streams have been investigated on this wetland during the assessment period. The obtained results show that these sources have a significant effect on the water supply of the wetland. Based on the available data and information, for example for 2006 and 2015, not taking the impacts of drainage system, channels, and traditional streams on this wetland into account will lead to the wetland water volume reduction of about 15% and 30%, respectively.

Harirud river with an international nature is shared between Afghanistan, Iran and Turkmenistan and currently there is no treaty among these states regarding the division of its water resources. In recent years, after the construction of the Doosti Dam by Iran and Turkmenistan, Afghanistan, as an upstream state is moving towards hydro-hegemonic policy in the region by building various dams which restrain and divert the water flow of this river in order to decrease the downstream countries’ water rights. On the other hand, due to the high importance of Harirud water resources for Iran, continuing this type of behavior by Afghanistan might cause conflicts and create security risks among these countries in the near future. Therefore, employing a descriptive-analytical approach, the study aims at examining the issue according to international legal documents in the field of sharing common water resources. Finally, the findings indicate that the best and most practical method for exploitation of Harirud water resources is based on the theory of limited territorial sovereignty and implementation of the principle of equitable and reasonable utilization of common water resources by Afghanistan, without causing significant harm to downstream states.

Groundwater is one of the most important resources of water supply for various uses in many regions all over the globe including Iran. Different contaminants severely affect these resources and might render groundwater unsuitable for consumption. Groundwater contamination by nitrate is a well known globally growing problem due to the population growth and increase of demand for food supplies. This study was conducted to evaluate the nitrate concentration in water resources of Ardabil aquifer using Geographical Information System. Water samples were collected from 63 wells in Ardabil aquifer during the September 2014 and analyzed for nitrate concentration. The average nitrate concentration from the wells was 39. 18 mgl-1. Based on the variography analysis, nitrate concentration showed a good spatial structure which may lead to the high performance of the ordinary kriging (R2=0. 508) in predicting the groundwater nitrate spatial pattern. Nitrate concentration was very high at the western parts of the aquifer where the Ardabil city and its agricultural lands is located. These results clearly indicates that the anthropogenic sources from human activities and agricultural development are the main reasons of the nitrate pollution in this part of the aquifer.

In recent decades, increasing water demand in Iran has resulted in excessive water usage, specially groundwater. Due to the increase in aquifer water usage, groundwater management should considerate to meet consumers needs and achieving a fair benefit in addition aquifer sustainability and future needs. This study aimed to manage and reduce water usage of Haji Abad aquifer in Hormozgan province. first, Groundwater simulation model was calibrated and validated by MODFLOW software and then, the new operation wells discharge values were calculated by using the cooperative method (bankruptcy) and these values were entered into the simulation model and the results were compared with the current situation. In this study, five bankruptcy methods proportional (P), Constrained Equal Award (CEA), Constrained Equal Loss (CEL), Talmud (Tal) and Piniles (Pin) are used to manage operation wells discharge, The annual discharge values of the operation wells are claimer demand and the amount of groundwater recharge which calculated by the simulation model in each polygon are the available water. In these five methods, groundwater head increased and overall aquifer status improved relatively well. Finally, the Bankruptcy Allocation stability index (BASI) for five methods was calculated and compared. compared.

In recent decades, water level of the Hoor-Al-Azim/Hawizeh wetland (located on border of Iran-Iraq) as Shared resources has reduced sharply. In shared watersheds, interactions between riparian countries of a water resource system can be considered by a system dynamic model. The proposed model simulated the interactions among water resource systems of Iran, Iraq and Turkey without interactions of Socio-economic subsystem over the period of 2004– 2016, which can be used to analyze various scenarios in the shared basin of Hoor-Al-Azim/Hawizeh. In addition, this study has developed a system dynamics model for several decision makers with different interests, based on integrated watershed. The model was validated for extreme conditions and the results showed well-calibration of the developed model to reconstruct the behavior of different parameters within the system. The results also showed that Tigris inflow to Iraq from Turkey has been decreased significantly during the simulation period. Subsequently, the inflow to the Hoor-Al-Azim/ Hawizeh wetland during the simulation period had been 61% less than the environmental flow averagely. Moreover, the model results for two scenarios of GAP project completion and 10% reduction in cultivated area of the three countries showed that wetland inflow decreases to 400 MCM and increases to 1900 MCM, respectively. In general, the proposed model can be used as support tool to evaluate decisions of policy-makers in the region. Thereupon, results of model for different scenarios indicate that improvement of environmental conditions would be approached by management alternatives based on integration of basin

The Mahi-Dasht aquifer located in Kermanshah province, west part of Iran. Water resources planning, development and management of Mahi-Dasht area has become inerasably complex as many factors, such as population growth and increasing demand on existing water supplies. To overcome the water shortage and increase water supply during critical demand period, interaction of surface water and groundwater has been investigated. For these reason two models, with and without interaction of groundwater and surface water were developed. These conceptual models (with/without feed from river) were developed in the groundwater MODFLOW PMWIN 5.3 model. Then the groundwater level and volume of aquifer were compared. The results shows that the groundwater level increase in wells near to the river, also the aquifer volume increasing too. Too increase the groundwater level as well as the aquifer volume, it is recommend that during the wet season, the flow of river can be used as recharge of groundwater.

Groundwater is a limited and vulnerable resource that is reversible in the conditions of balance between nutrition and extraction. Mahidasht plain of Kermanshah province, which in the past was one of the most fertile and vast plains in the west of Iran, the trend of decreasing groundwater, especially in recent years, is quite evident.Methodology: It has been tried in this article by using Mahidasht plain underground water modeling using ModFlow model, Mahidasht plain underground water stability based on analysis of the current situation and four management scenarios (scenario of continuation of the current trend, scenario of adjustment of permits and reduction of 30 The percentage of underground water extraction, the scenario of removing unauthorized wells and adjusting the permits and reducing the extraction of underground water by 40 percent and the scenario of increasing the extraction of underground water and developing unauthorized cultivation) should be investigated. The results show the unstable situation of the Mahidasht aquifer, and the application of the management scenario of 30-40% reduction in groundwater extraction will not stabilize the central areas of the aquifer. The unstable situation of this plain means many social, economic, political, security and environmental risks. In other words, this plain, more than ever, wants to control the harvest and should be prioritized in the water scarcity adaptation programs of politicians, planners, managers and all water guarantors in the region and removed from the list of susceptible areas for agricultural development. It is recommended to follow the principles of quality sustainability of the aquifer, and encourage farmers to change the harvesting pattern from agriculture to industry with incentive policies.

Numerical simulation of groundwater table variations can be an effective tool for water resources management. In this study, water table variations of Shahdad aquifer located in Kerman provience, were simulated using Groundwater Modeling System (GMS) software and MODFLOW model. Changes in the aquifer water level indicate a decrease in the aquifer in the northern, eastern, southern, and some central parts of the aquifer. The developed model was calibrated using the monthly water level measurements for the period of 2012-2013 and then validated using the monthly statistics for the water year 2015-2016. Aquifer properties including hydraulic conductivity, storage coefficient, and recharge rate were estimated by inverse modeling with PEST Code. The coefficient of determination for the validation stage was calculated as 0. 95, demonstrating the good consistency of observed and predicted data and the ability of the model to predict future aquifer water table variations. A sensitivity analysis showed that the model is more sensitive to the well discharge than to surface recharge or hydraulic conductivity. Monthly reduction of discharge from wells by 30 percent can stop this phenamena.

In this study, the concept of exploitation risk was used to calibrate the DRASTIC vulnerability index, considering the inherent nature of vulnerability in the aquifer. The concept of risk was defined based on three parameters: nitrate concentration, water resource exploitation density, and land use changes, which were combined and prepared using a fuzzy approach. The defined concept was used to calibrate the results of the DRASTIC vulnerability index using two machine learning models. The results showed that using the risk concept for calibration was superior to using nitrate concentration due to the increased correlation, and this concept was used for calibration. The correlation between the DRASTIC vulnerability index and risk increased from 0.35 before calibration to 0.75. Based on the results obtained in the calibration stage, it was determined that the ANFIS-EO machine learning model was determined as the selected model due to the higher correlation. Parametric analysis of the vulnerability index also showed that in the DRASTIC index, 6 parameters had increased weight and consequently the rankings had increased significantly. The computational results also indicated the fact that the northern and northwestern parts of the aquifer had higher sensitivity due to the increase in nitrate concentration resulting from agricultural development and population concentration, which was clearly evident in the DRASTIC index.

Concept of vulnerability used in order to determine the pollution risk of Qazvin plains aquifer. Vulnerability map of the aquifer was developed by qualitative rating, and then pollution risk map was provided. Results shows, some part of the plain and south eastern part has high pollution risk, because of the high electric conductivity (EC) and the high groundwater level respectively. Some parts were in the low risk region and due to the high ground water level the confirmation based on the chemical analysis is unexpected. By using Nitrate data the vulnerability maps reveal dramatic changes. In the corrective drastic method, areas which were in low risk region in conventional drastic moves to the moderate risk region. Also, results from the fuzzy drastic was close to the corrective drastic. Major parts of the plane were in the moderate risk region. From the experts point of the view the results from the corrective drastic was realistic. Results from sensitivity analysis shows that weight of the aquifer depth layers and feeding decreased, unsaturated slop layer's weight and hydraulic conductivity increased. Also, the weight of the ambience of the aquifer layers and soil was remained constant.