مجله آبخوان و قنات
سال چهارم شماره 2 (پیاپی 7، پاییز و زمستان 1402)

Today, groundwater pollution has become a serious environmental problem. On the other hand, climate change affected the quality of aquifers. The results showed that the quality of groundwater resources changed over the time and some cations such as arsenic, chromium and some anions like mercury, fluoride, and nitrate penetrated into the water sources. Research showed that there were various methods to eliminate pollution in groundwater, including traditional and cheap techniques also, chemical precipitation methods, ion exchange, absorption, and membrane filtration. Therefore, in the present study, with analytical and descriptive investigation, some common pollutants in polluted aquifers and various methods to reduce pollutants from water were stated. Also, since nanotechnology guarantees long-term access to safe drinking water, some methods of nanoparticle synthesis and their wide applications in reducing aquifer pollution were investigated. The results of these studies showed that nanomaterials can increase the rate of chemical reaction, compatibility with the environment, and selectivity in reducing pollutants from water.

One of the methods for groundwater monitoring is the calculation of the water balance, which provides important information about the status and changes of aquifers. However, estimating the components of the groundwater balance is challenging, which can reduce the accuracy of the results. This study aims to improve the accuracy of evapotranspiration estimation in the groundwater balance using remote sensing, which leads to better estimation of return flow and infiltration from rainfall. Consequently, the groundwater balance is calculated with higher accuracy. For this purpose, data from observation wells, precipitation, withdrawals, rivers, and aquifers in the Qomsheh study area between 1992 and 2016 were used to evaluate the groundwater balance. A conceptual water balance model and the WaPOR remote sensing product were used to estimate ET. Finally, the observed water balance was compared with the calculated water balance. The results showed that during the study period, 40.54 million cubic meters (MCM) of water infiltrated into the aquifer through precipitation, irrigation, and surface flow. In contrast, 262 MCM of water was withdrawn from the aquifer, of which 105.53 MCM returned to the aquifer. Also, 10.21 MCM of water entered as lateral flow and 0.73 MCM of water exited the aquifer. The groundwater balance was estimated to be 120.02 and 119.09 MCM using the computational and observational methods, respectively. Comparison of these two water balances shows that using WaPOR remote sensing products in estimating the components of the water balance reduces uncertainty and increases the accuracy of calculations in the Qomsheh study area.

Predicting groundwater potential is crucial for systematic development and planning of water resources. The main objective of this study is to develop machine learning models including Random Forest (RF), Decision Tree (DT), and Support Vector Machine (SVM) for predicting potential groundwater areas in the Birjand plain. Therefore, for the implementation of this study, geohydrological data related to 37 groundwater wells (including the number and location of wells and groundwater levels) and 17 hydrological, topographical, geological, and environmental criteria were used. Feature selection was performed using Support Vector Machine's least squares method to determine effective criteria for improving the performance of machine learning algorithms. Ultimately, predictive maps of groundwater potential were prepared using DT, RF, and SVM models, and the performance of these models was evaluated using the Area under the Curve (AUC) and other statistical indicators. The results showed that the DT model (AUC=0.89) has very high predictive capability for groundwater potential in the study area, and elevation was identified as the most important factor in predicting groundwater potential in this area. The findings of this study can serve as a guide for decision-making and appropriate planning in the optimal use of groundwater resources.

 In this article, we will examine the successful experimental methods of protecting and reviving the Qanat with three case examples in Yazd province, each in turn in the least watery areas of this province, in areas without aquifers that supply drinking water to the people of the Mazreano Dehshir, Khamsian of Ashkezar and Dihook Kharanaq villages. First, the action of physical protection and increasing water flow was introduced as the most important methods of protecting and revitalizing the Qanat. Protective action in three parts A: resilience against external environmental factors, including a set of protection operations for well rods and Qanat furnaces, B: Improvement in order to prevent disruption in the internal functioning of the Qanat, which includes the operation of removing debris, dredging, breaking calluses doubling the Qanat furnace with kaval in the collapsed area and c: the construction of the flood diversion dam was defined. was investigated to increase the flow in a superficial way Earth dam operations for artificial feeding and for the underground method construction of underground dam as efficient and effective methods.The results showed by implementing these measures the destroyed Khamsian Qanat was put into operation with a flow rate of 0.5 liters per second And while protecting against possible future floods, the sustainability of the supply of drinking water for the people of this village was ensured.

water and agriculture sector, has faced significant impacts from climate change. Various international treaties have been introduced involving multiple countries to urge them to fulfill their obligations by defining common international responsibilities. In this research, using the research method, based on the qualitative research method, the laws of the water and agriculture sectors of 14 selected countries are analyzed and the results are shown. developed countries have generally enacted laws earlier than developing ones, with a higher quantity of legislation passed. The peak of legislative activity was observed between 2009 and 2014, but since 2016, the trend has declined as most countries have established basic regulatory frameworks. South Korea, Germany, the UK, and Japan have shown greater advancement in the field of climate regulation compared to other countries. To ensure food and economic security, conserve natural resources, and promote sustainable development in the face of climate change, it is recommended to enact comprehensive legislation covering mitigation, adaptation, and disaster risk management. Additionally, existing laws should be revised and updated to address today's conditions and climate challenges effectively. The need to amend the existing laws to adapt to the new challenges of climate change is imperative.

The management of water resources, especially groundwater, is of particular importance in arid and semi-arid regions. Improper understanding and unsustainable exploitation in these areas will result in irreparable damage, such as severe and irreversible groundwater level decline, reduction in well and aqueduct discharge, and changes in the pattern of groundwater flow. Therefore, the aim of this research is to investigate the decline in the groundwater levels of Mashhad Plain, which is selected as one of the most important and largest plains in Khorasan Razavi province. In order to conduct this study, the data from 62 observation wells were examined over a period of five years (2011-2016, 2016-2021). Initially, the statistical data was collected and organized using Excel 2017 software, and the hydrograph representing the aquifer of Mashhad Plain was plotted. Subsequently, using ArcMap 10.8 software and the Inverse Distance Weighting (IDW) method, maps of the groundwater level and water table for an 11-year period and two consecutive five-year periods were generated. The results obtained in this study indicate that the groundwater level in this aquifer has, on average, increased by 0.36 meters in the first five years and 0.32 meters in the second five years for the specified time period. The central, southeast, and northwest parts show the highest increase in reaching the groundwater level. Additionally, the hydrograph representing the Mashhad aquifer shows an average annual decrease of 0.33 meters in groundwater level over the 11-year period.

Given its location in the arid belt, South Khorasan Province faces an increasing demand for water due to the simultaneous growth and development of the agricultural and industrial sectors. This necessitates proper management tailored to the region's climatic conditions. Therefore, a quantitative and qualitative study of the region's water is essential for appropriate utilization and optimal management. Various indices exist to assess the quality of groundwater for drinking purposes, including GQI and WQI. In this article, a 10-year qualitative study of groundwater quality using WQI and GQI indices was conducted based on data from 29 well rings, which included parameters such as Na, Mg, Ca, Cl, SO4, TDS, HCO3, NO3, and pH. Raster maps depicting the concentration of these parameters were prepared using the Inverse Distance Weighting (IDW) method in GIS software. The GQI values for the Birjand Plain for the periods 87-90, 90-93, 93-96, and 96-97 ranged between 87-94, 85-93, 85-94, and 86-94, respectively. The WQI value for the period 87-97 ranged from 56 to 84. In conclusion, it can be inferred that the study area ranges from acceptable to suitable in terms of the GQI index, and from poor to very poor in terms of the WQI index.

Groundwater aquifers are the main source of water for billions of people living in arid and semi-arid regions. Major changes in rainfall, groundwater pumping and feeding, and severe soil erosion, floods, and droughts are among the most noticeable consequences of climate change. All this complicates the challenge of conserving groundwater resources for the foreseeable future. These scenarios highlight the need to rethink current strategies for groundwater studies. This paper deals with the application of finite elements in groundwater studies. This paper analyzed Web of Science data using Biblioshiny - a powerful bibliometric analysis tool based on R software. The study shows that the Quebec National University of Scientific Research and the Indian Institute of Technology are the most active research centers on the use of finite elements in groundwater studies, and China, America, Canada, Germany, Italy, France, Great Britain, and Iran are the leading countries in this field. Are. This distribution reflects the worldwide interest and participation in research related to the application of finite elements to groundwater problems. Based on this research, the current popular topics in the world regarding the application of the finite element method in groundwater studies are: "seepage", "deformation" and "stability analysis". The present study not only highlights the relationship between collaborations and scientific advances and trends in scientific collaboration but also serves as a model to show new research directions in the field of finite element applications in groundwater.

After the construction and impoundment of Zamkan Dam, water leakage was observed in the left side of Zemkan Dam reservoir through the left abutment in the amount of about 225 liters per second. Due to prevent the development of transmission channels and possible Damage to the Dam structure, water impoundment was stopped in the level of 1532 meters. After tracing test study, it was concluded that the water leakage does not harm the stability of the Dam, but in order to prevent the water leakage from Dam and conserve it for agricultural purposes, it is suggested to construct a watertight curtain. The simulation of water leakage has been performed for the normal water level condition and the amount of water leakage in this level was estimated to be about 700 liters per second (Karimi, 1402). The current goal of managers is to implement a waterproof curtain to prevent water leakage. The cost estimate for the implementation of the waterproof curtain is about 278.000.000.000 Toman. In this study, in order to prevent high costs of the watertight curtain implementation, an alternative project with a much lower cost was proposed. In order to this matter, the water leaking from downstream of the Dam, which is drained at the bottom of the valley is pumped to a channel which was designed and implemented for the water conveyance to the downstream agricultural lands. The final economic cost estimate of this project is 96,000,000,000 Toman, which is more economic than the grout curtain construction.

In recent decades, the use of groundwater for irrigation, drinking, and industry has increased in developing countries such as Iran. This increase, in turn, improves food security and reduces poverty in these areas. However, reducing the level of the water table and sustainable development are concerns. These concerns have increased, especially regarding the alluvial aquifer of the Ajabshir plain, which plays a significant role in providing water in the area. Considering the growth of the population and the water needed, it is very important to study the water quantity and quality for the future and the well deepening. There are several methods to determine the maximum depth of deepening. However, this study emphasizes the fluctuations of the groundwater level as a result of them instead of the relatively complex studies of modeling and water balance. For this purpose, after collecting the data, the maps of the groundwater isodepth, isolevel, fluctuations, and aquifer bedrock were drawn in the GIS software. Then, the unit hydrograph of the plain was prepared to determine the amount of groundwater level drop. Population growth and water demand were determined for the horizon of 1420. The findings of this research indicate that the overexploitation of groundwater resources will have consequences such as a drop in the groundwater level (equivalent to 6 m), a decrease in the quality of the groundwater, and subsequent land subsidence. The minimum level for well deepening in the Ajabshir aquifer varies between 1250 meters and 1290 meters.

The Zeydon alluvial plain with an area of approximately 370 Km2 is located in the south west of Behbehan City and at about 180 km from Ahvaz in Khuzestan province.To understand the chemical characteristics of groundwater resources of the Zeydon plain and the natural impacting factors affecting the groundwater quality, groundwater sampling was conducted in the spring 1400. To assess the chemical quality of groundwater from a combination of hydrochemical methods including Piper diagram and iso-values maps and statistical methods such as factor analysis, correlation and cluster analysis were used. The dominant water type in the plain is sodium-chloride and the factor analysis indicated two geogenic factors. The first factor depicted strong relationship between sodium and chloride reflecting hydrochemical processes related to evaporate minerals and the second factor displays robust correlation between calcium and sulphate resulting from dissolution gypsum and anhydride minerals. Based on cluster analysis groundwater samples fall into two catagories.

The water crisis has a direct link with the issue of governance and policy-making in the field of water resources management of a country, so that this problem in Iran is more than caused by climate changes, as a result of the accumulation of ineffective policies in the field of water resources management in recent decades. Achieving sustainable governance of water resources is possible with the participation and cooperation of the government, civil society, organizations and people's organizations, and in general, the inclusive participation of all classes and stakeholders of water. Reforming the management structure governing water resources is one of the necessary measures to face the water crisis, which requires fundamental changes in the development model, the political economy of water and the reform of the governance structure. Based on this, the promotion of efficient and sustainable governance indicators requires the improvement of government policies, as well as the revival of local resource management mechanisms and the involvement of local users in this process.