جستجوی مقالات مرتبط با کلیدواژه « آب زیرزمینی » در نشریات گروه « آب و خاک »

Water is a basic and important resource for human development and economic growth. Water is also important for the agricultural sector. On the one hand, the lack of water and on the other hand, the increase in water demand for different parts of the society, has faced most of the developing countries with a serious and important problem. Water for the agricultural sector is decreasing and scarce every day. Also, with the increase in population, the demand and consumption of water in rural areas and especially in the agricultural sector has increased. Lack of water has caused various problems in different regions. The purpose of this research was to Identifying the consequences of water reduction in Zanjan township from the perspective of farmers with wells.

The current research was a quantitative and applied research. The statistical population of this research was farmers have wells in Zanjan township (N=8017). The sample size was estimated to be 367 people based on Cochran's formula. The sampling method was multi-stage cluster sampling. Data collection tool was a researcher-made questionnaire. The content validity of the questionnaire was confirmed by experts and researchers in the field of water management and the reliability of the research tool was confirmed by using the pilot tet and calculating the Cronbach's alpha coefficient (α = 0.94).

Using the results of exploratory factor analysis, the consequences of water shortage in the rural areas of Zanjan township from the perspective of farmers summarize in six factors including the increase of plant and animal diseases, change of agricultural land use and weakening of villagers financial ability, dryness and reduction of water in fountain and rivers and reduction of pastures and the area under cultivation of agricultural products, the lowering of level of underground water resources and the reduction of the water supply of wells, reducing the incentive to invest in agriculture and increasing soil erosion, water and soil salinity and increasing  disputes and conflict in the village. These six factors were able to explain 63.48 of the total variance of the impacts of water shortage.

Corrosion and precipitation are two problems of water quality management for the water transmission and distribution systems. Hence, the present research was conducted to investigate the potential of corrosiveness and precipitation in the drinking water supply wells of Gorgan city using some indicators.

Here, the results of chemical analysis of 63 wells supplying drinking water in spring and autumn were used. First the temporal and spatial changes of physicochemical parameters were investigated using one-way variance statistical test and IDW method, respectively. The dominant type, the origin of chemical ions, and their evolution process in Gorgan aquifer were studied. In this research, water hardness, LSI, RSI, CR and LS were used to determine the corrosion and precipitation potential of drinking water in Gorgan city. Finally, the temporal and spatial changes of indices calculated in two seasons were investigated.

The high concentration of calcium ions in groundwater, due to the recharge of the aquifer by the limestone series located in the southern highlands, has increased its hardness. The results of RSI and LSI revealed that the majority of wells are corrosive and their water has the potential to decompose CaCO3. Also, the corrosive property of water in the direction of groundwater movement is significantly reduced and the water precipitation property is increased. Also, 90 and 98% of the groundwater resources of Gorgan city have a corrosion ratio of less than one. Therefore, it is possible to transfer water from most wells with any type of metal pipes.

Due to the limitation of surface water resources and excessive exploitation of underground water, the underground water table in many plains of Iran is in an unfavorable condition. One of these critical plains is the Dehgolan Plain, which is still facing a water shortage crisis despite its designation as a prohibited area. Therefore, in this research, the effect of tax and subsidy incentive policies for each added or saved cubic meter of water consumption on the changes in the cultivation pattern has been investigated in three scenarios of 10, 20, and 30 percent increase in the shadow price of water (714 Tomans) in 2023. The required data were collected by referring to Kurdistan Regional Water Company, Agricultural Jihad Organization, and the country's water demand system for seven major crops including Wheat, Barley, Forage corn, Potato, Cucumber, Alfalfa, and Rapeseed in Dehgolan plain. Then, the data were analyzed using the positive mathematical programming (PMP) model. The results showed that the application of tax and subsidy policies pushes the cropping pattern towards low-water-absorbing crops such as barley, wheat, and canola. It was also found that these policies reduce water consumption and gross farm yield. These findings show that the mentioned incentive policies can be an effective tool for managing water consumption in the agricultural sector. Of course, it is necessary to consider alternative solutions such as the use of new irrigation methods in addition to these policies to prevent negative effects on farmers' income.

Today, fresh water sources are very important in human life. During the past years, population growth, development of industries, and agriculture have increased the need for water and subsequently increased the withdrawal from groundwater sources. This increase in withdrawal has occurred without considering the capacity of the aquifers. While logically, the exploitation of an aquifer should be limited to its dynamic storage, in most regions, the static reserves of aquifers have been used to a large extent, and it seems impossible to return these aquifers to their original state. The dynamic storage of the aquifer is actually a part of the storage volume of the aquifer, which has fluctuations, and by examining and determining these fluctuations, it is possible to estimate the permissible amount of exploitation of the aquifer. But the static storage of the aquifer, which is very important, is among the old and stable storage that has been stored for many years. The use of static aquifer storage causes events such as subsidence. The drying up and lack of water in many aqueducts, springs, and extraction wells across the country is one of the consequences of the overexploitation of groundwater resources. In the arid and semi-arid climates of Iran, factors such as climate change and water scarcity, along with overexploitation of water resources, especially groundwater resources, have caused the groundwater levels to decrease. In some areas, we are witnessing irreparable subsidence. As a result, it is necessary to manage and control the extraction of groundwater resources before the crisis occurs and reaches an irreversible level. In this regard, monitoring and controlling the condition of the aquifer using computer models is essential.

In the present study, the modeling and quantitative investigation of the groundwater condition of the South Mehyar-Dasht Asman aquifer in the Gavkhoni catchment area has been done by the MODFLOW 2005 model and groundwater modeling system )GMS 10.4.5( software. GMS software is one of the few with good performance and has been used in groundwater studies in many countries worldwide. This software simulate groundwater both quantitatively and qualitatively. The MODFLOW (Modular Ground Water Flow) model is used to simulates groundwater flow in aquifers with specific boundary conditions, assuming the necessary values for hydraulic conductivity and other aquifer parameters. The program allows the user to select only the modules needed to study the desired system for specific hydrogeological processes and activate or deactivate a particular part. These features have made the MODFLOW model the most efficient and accessible groundwater model today. For this purpose, the statistics and information from 15 years ending in 2013 of the Iran Water Resources Management Company and topographical information extracted from satellite data have been used to model the groundwater of the South Mehyar-Dasht Asman aquifer.

After running the model, the parameters of hydraulic conductivity, anisotropy, or HANI, RCH, SY, and parallel lines of the groundwater level were obtained. In the next stage, or the calibration stage, the model was calibrated by the parameters mentioned to minimize the difference between the observed water level and the calculated water level. In the sensitivity analysis stage, the calibrated value of the parameters is systematically changed to determine the model's sensitivity to the parameters. In this stage, it was found that the model received the most influence from the parameters of anisotropy and hydraulic conductivity. To validate the model and measure its accuracy, validation was done. The RMS error was 2.21, which is a good value, but for more certainty, the RMSE was also calculated, and its value was 23 %, which is very appropriate considering the long-term simulation period. Finally, the numbers extracted from the FlowBudget engine based on the calibrated MODFLOW model revealed that during the 12-month simulation period, a particular share of the aquifer's fixed storage was reduced on a daily average basis, resulting in an average drop of 7.5 m in the aquifer's groundwater level during this period. We see that the most significant drop is related to the eastern part of the aquifer.

In this research, the South Mehyar-Dasht Asman aquifer was simulated and modeled by the MODFLOW model and GMS software, and the groundwater level was investigated during the simulation period. The model was calibrated to reduce the difference between the observed and the calculated water level. The sensitivity analysis section also examined the influence of the model parameters. Validation was also done to increase the accuracy of the model's performance. The coefficient of determination or R-squared correlation was 0.9971, which seems to be a good number compared to other studies. The results showed that the water withdrawal is greater than the aquifer's recharge, and a specific volume of the aquifer storage is always reduced during the simulation period, which caused a drop of 7.5 m in the groundwater level. The groundwater level of the South Mehyar-Dasht Asman aquifer continuously decreases from the western part to the eastern region, and the lowest groundwater level is related to the east part of this aquifer. Declining groundwater levels, water shortage conditions, and overexploitation, increase the risk of subsidence, which is an irreversible event. To prevent this from happening, the amount of water taken from the aquifer should be proportional to its capacity, and control and management measures should be carried out on a large scale. Computer models and up-to-date methods help to maintain and manage these water resources as well as possible. Factors such as the dryness of the Zayandehroud River, excessive harvesting, and lack of water have led to the aggravation of the adverse environmental effects of the Gavkhoni International Wetland, and this has increased the importance of simulating the existing aquifers in this basin. Due to the fact that no study has been done on the simulation of the groundwater of South Mehyar aquifer-Dasht Asman and also the duration of the simulation period is 15 years, this research can be a basis for future studies and provide the possibility of comparison with other studies.

Preservation and proper management of water resources are one of the essential fields of study in the world. In arid and semi-arid regions like Iran, quantitative and qualitative management of underground water resources is particularly important. In most hydrological issues and groundwater resources studies, groundwater statistics and information availability are critical. To collect information without side effects, comprehensive and sufficient data collection with the help of a groundwater monitoring network is very important. In line with the sustainable management of renewable water resources, the need for a network of underground water observation (monitoring) wells to accurately measure the water level is necessary and necessary. Considering the complexities of the underground water environment and the high costs of conventional monitoring methods, inventing new technologies and using advanced methods in this matter will significantly help improve the underground water systems. One of the parameters of particular importance in monitoring groundwater quantity is the groundwater level. Therefore, this parameter should be measured or estimated as accurately as possible. In recent decades, the use of computer and calculation models to monitor the level of underground water has developed significantly. Considering the importance of underground water resources and network monitoring, to save time and money, in this research, principal component analysis and Shannon's entropy theory were used to monitor the underground water network of the Dezful-Andimeshk Plain.

This research used monthly groundwater level information from 77 observation wells in the Dezful-Andimeshk Plain during 2018-2019. Groundwater level information is collected twice a month. Principal component analysis and Shannon entropy methods were used for monitoring. In the current research, the number of statistical periods for each well is 24, less than the total number of observation wells. Twenty-four observation wells around it were used to monitor each well. In groundwater level monitoring, the relative importance of each well is defined by the ratio of the number of times that well is recognized as a compelling well to the number of times that well is included in the analysis of the main components. This ratio shows the importance of each well compared to other wells. Therefore, to save time and costs, less important wells can be removed in the monitoring of the underground water level. In 1948, Shannon showed that events with a high probability of occurrence show less information, and on the contrary, the lower the probability of an event, the more information it provides.  In this method, the weight of each well was obtained using Shannon's entropy theory. Any well that has a higher Shannon entropy weight contains more important and unpredictable information and should be preserved. On the contrary, a well that has a lower Shannon entropy weight can be removed from the network. Principal component analysis and Shannon's entropy method in the current research were done with the help of coding in Matlab software due to the high volume of calculations.

To rank the wells, the threshold limits are equal to zero, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 and one considered. At threshold one, only wells that have a rank of one remain (wells that are recognized as effective wells in all analyses) and threshold zero includes all wells (effective and ineffective). According to the obtained results, increasing the error in the threshold zero to 0.7 is gradual, but in the thresholds 0.8, 0.9, and one, the error value increases with a high slope. So, the amount of error in the thresholds of 0.7, 0.8, 0.9, and 1 has been calculated as 12.2, 17.7, 25.3 and 34.2 respectively. Therefore, the threshold limit in the current research is considered to be 0.7. However, the number of wells effective in monitoring the underground water level is reduced from 77 to 32. Shannon's entropy weight values were also calculated for all wells. 11 wells have the highest value of Shannon's entropy weight, which shows that they contain the most information.

The general comparison of the results of the two methods showed that all 11 wells with the highest weight in the Shannon entropy method were also observed as effective wells in the principal component analysis method. By knowing the effective wells in the region, firstly, in the face of lack of time and money, it is possible to use known effective wells for monitoring secondly, by removing ineffective wells, there will be little change in the average level of underground water. It is not possible, or in other words, the tracking error does not increase significantly. Comparing the results of the two methods showed that the remaining wells in Shannon's entropy theory are among the wells identified in the principal component analysis method. Also, considering that the wells in the region were built by the Khuzestan Water and Electricity Organization considering the types of uses, removing the ineffective wells will not affect the process of using the information of the wells. It is recommended to use principal component analysis and Shannon entropy for groundwater quality monitoring in the study area. Additionally, it is suggested to monitor the quality of the underground water network in the study area using the methods used in future research.

Due to the semiarid and arid regions of Iran, it is suffering from water scarcity and severe droughts. Khorasan Razavi province is no exception to this rule, and accordingly it is facing the lack of sufficient water resources, which need to be improved by approaches used for optimal allocation of water resources. Water pricing can be an effective tool of demand management and the optimal allocation of water resources as well the protection of water resources.

Therefore, the aim of this study was to investigate the willingness to pay (WTP) for irrigation water for the cities of Kashmar, Kuhsorkh, Khalilabad and Bardeskan using the Heckman’s two-stage model during 2019-2020.

The results demonstrated that 40 % of farmers were willing to pay more than the current tariff for access to irrigation water. Thus, the mean WTP for irrigation water was 518, 594, 606 and 569 Rials for the cities of Kashmar, Kuhsorkh, Khalilabad and Bardeskan, respectively. The results of the ordinary least squares (OLS) also showed that the farmer's income had the highest positive effect on WTP for irrigation water with a coefficient of 0.21, indicating that the higher the income of farmers consuming irrigation water, the higher the farmers’ WTP for using irrigation water in order to have easier access to water resources. However, variables, such as dependency burden and area of cultivation had a significant negative effect on WTP for irrigation water, suggesting that as the dependency burden, and area of cultivation increased, farmers was less willing to pay for the use of irrigation water. Given the importance of water for the farmers living in the study regions and their high WTP, it therefore is recommended to provide better and easier access to water resources for the farmers by transporting water from the water-rich region to water-scarce one.

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.

The reduction of water quality in groundwater resources over the last half century has attracted increased amounts of attention from hydrogeologists. Therefore, different methods called quality indicators of ground water have been used to check the quality status of these vital resources. However, the use of expert judgments is one of the weaknesses of these qualitative models. In this research, it has been tried to use the entropy theory to evaluate the quality of ground water and reduce such judgments of taste. Sixteen water well samples were extracted along the Abdalan aquifer for physical and chemical analyses in 18 months.The results of the application of the entropy method showed that chlorine has the highest rate of influence on the quality of underground water in the region and is the main factor in the reduction of water quality. Also, the results of the entropy method showed that sodium and potassium have the most instability and constant changes. The highest entropy weight is related to magnesium and it shows that there are stable and uniform changes in the underground water of the studied area. In general, the results showed that 74% of the groundwater samples in the study area have good quality, 13% have average quality, and the other 13% have poor quality. Also, the inverse relationship between the drought index (SIAP) and the groundwater resources quality index (EWQI) in the 18-month period shows the leaching effect of evaporative formations in the conditions of increased precipitation.

Aquifers, as the primary source of freshwater in coastal zones, are always threatened by saltwater intrusion, so assessment of groundwater behavior in response to the seawater has ever been of interest to researchers. Employing physical-laboratory models is one of the conventional methods in the study of groundwater dynamics in contact to saltwater. In this paper, the experiences of setting up a laboratory model of seawater intrusion issues are presented in detail. The model is 118 cm long, 12 cm wide and 60 cm high and uniform Glass beads are used as the porous medium in two different grain sizes. In this research, the challenges of construction, keeping the head and salinity constant in the side and main tanks as well as estimation of seepage flow rate have been studied. Results showed that the tests performed in coarse-grained medium reached a steady state in a shorter time than fine-grained one, with more accuracy which led to less salinity variation during the test. Furthermore, the conducted analysis on the dyes used as tracers of saltwater revealed that the amount of absorption of a dye seems independent from the grain size. Among all employed chemical and food dyes, Sunset-Yellow showed a very good match with saltwater movement in the medium. The findings of current research present a useful guideline for carrying relevant experiments out as well design of a successful setup.

Among the problems faced by artificial feeding methods, we can mention low rainfall, limited water resources, high temperature and high evaporation, high sediment yield due to poor vegetation cover, etc. Artificial feeding methods in these areas should be designed in such a way that it has maximum efficiency from the available water resources. In this research, it has been tried to reduce the aforementioned problems by presenting a new method of artificial nutrition suitable for desert areas. In order to design a suitable method of artificial nutrition, sufficient information about the distribution of water flow in the soil is needed. On the other hand, research on the distribution of water flow in porous media without modeling the field conditions is time-consuming and expensive. In the current research, the issue of determining the infiltration capacity in the unsaturated environment was discussed using the integration of the infiltration trench and the permeable pipe in the laboratory environment.

For this purpose, a physical model was built in which water was injected into the unsaturated environment through a permeable pipe and a trench. The input flow to the model included 5 flow rates of 1, 1.5, 2, 2.5 and 3 liters per minute. With the beginning of the experiment, which was entered into the model with the mentioned flow rates, the amount of progress of the moisture front was determined every 5 minutes. This process continued until the moisture front reached the water level. At the same time as the water was removed from the model, the output flows were measured every 5 minutes. The way water moves in the unsaturated environment and the formation of the moisture front was photographed and the images were analyzed using Plot Digitize and AutoCAD software. In the next step, after creating a flow in the porous medium, the volume of passing water was measured in different conditions at a certain time. The amount of water output from the model depends on factors such as the flow rate entering the model, the dimensions of the model, the slope of the ponding surface, the distance between the bottom of the trench and the ponding surface, the texture of the soil, the length of the trench, the width of the trench, the height of the permeable pipe to the bottom of the trench, the average diameter of the permeable material, and the entry time. The water depends on the model until it reaches the stagnation level and the time it takes for the water to reach the stagnation level until the end of the test. In the experiments, the input flow to the model was variable and other factors were considered fixed. After the water reaches the stagnation level in time intervals of 5 minutes for 60 minutes (a fixed time, the duration of which is obtained according to reaching the peak output flow rate from the model and preliminary tests for the lowest flow rate) It was measured for all model inlet flow rates. Next, after the completion of 60 minutes, the amount of water output from the model was measured for another 30 minutes. In flow rates of 2.5 liters per minute and 3 liters per minute, due to the fact that the inlet flow rate was higher than the capacity of the model, the excess water volume overflowed from the model. Then the inlet was cut off and for another 120 minutes, the output flow rate from the model was measured in 5 minute intervals. Then, the volume of water entering the tank (V_in) and the volume of water leaving without calculating the base flow that was mentioned earlier was measured to simulate the static level, V_out=(V_B-V_A). V_A is the volume of water input to simulate the static surface and V_B is the volume of water output from the model. The performance of the model was calculated based on V_out in relation to the volume of water coming out of the model without calculating the base flow rate as maximum 〖(V〗_(out max)) and also V_out was calculated in relation to V_in.

The highest penetration capacity of the model was determined to be 2.049 liters per minute. The results showed the trend of changes in the output flow from the model, the time the moisture front reached from the trench to the reservoir surface, the average infiltration velocity, V_out, the time to reach the maximum output flow from the model, and the slope of the water discharge line from the model after approaching the flow rate proportional to the capacity. The influence of the model has decreased. The performance of the model was evaluated based on V_out during the duration of the experiment in two modes. The best performance of the model was related to the flow rate of 2 liters per minute, which is the closest flow rate to the flow rate corresponding to the infiltration capacity of the model. The results showed that the performance at a flow rate of 2 liters per minute in the case where V_out was measured in relation to V_(out max) (water entering the model is less than the infiltration capacity of the model), 96% and in the case where V_(out max) was compared to V_in was taken into consideration (water flow entering the model is greater than the infiltration capacity of the model), its performance was determined to be 98%. In the presented artificial feeding method, the inlet flow rate through the permeable pipe should be designed according to the infiltration capacity of the trench so that the maximum capacity of the trench is used and water loss is minimized.

Due to the sharp decline of the underground water in the country's plains due to their indiscriminate extraction for agricultural purposes, managers are looking for solutions to manage and restore underground water tables. One of the solutions to compensate for the drop in the underground water level, which is one of the most effective factors in destroying the discharge capacity and increasing the quality in the underground water area, scenarios of reducing withdrawal of farming wells and prepare prohibition plans with the least uncertainty based on the regional sensitivity to pollution. The purpose of this research is to predict the flow and pollution conditions of the area based on numerical models, so that the level network and the direction of the underground water flow of the plain using MODFLOW software in a long-term period and the development of the prediction model using Calibration and validation operations should be performed on the base period of the studies in order to be able to implement the forecast scenarios by applying restrictions and reducing harvesting on aquifer exploitation resources, and specifically agricultural wells, until the stage of stable hydrograph extraction of the plain.

This research was carried out with the aim of estimating and predicting the state of pollution in the urban pollution site, using MODFLOW and MODPATH computer programs in GMS software. To achieve this goal, in the first step, the numerical model of the aquifer flow was prepared and calibrated by the MODFLOW code. Then, the MODPATH code was used to track the contaminated particles in the steady-state progressive method. In the second stage, the impact of the scenario of increasing and decreasing the pumping from the exploitation wells on the travel time, the length of the path and the catchment area of the leachate particles leading to them was predicted and evaluated by the regressive method. In the third step, the tracking of particles leading to qualitative sampling wells in the plain was predicted and evaluated by regressive method in steady state.

According to the automatic calibration and validation approach, the underground water flow model produced the least statistical deviation on the optimization parameters. Also, the particle transfer quality model was correctly implemented on the groundwater flow prediction model. In the Babol aquifer, the waste disposal area outside the designated aquifer is saturated. It was observed that, by adjusting the parameters of the simulation of the transfer of residual pollution cloud particles, an estimate of the concentration was applied to the permeable boundaries and the channel network. This means that in the simulation of particle transport, here the source of pollution spread is the channel network and permeable boundaries, which will be directly affected by pollution during periods of rainfall and especially floods. The concentration limit was given to the model in the form of variable figures based on discharge and precipitation in the range and equal to the primary stable threshold of the research subject (landfill). Based on the cumulative diagram of the outlet concentration from the permeable boundary and flow channel in the southeast region, the trend of changes in the cloud pollution concentration diagram, in the qualitative modeling of the plain, shows that in the forecast period, the increase in concentration will increase linearly. Considering that the waste disposal location is outside the plain, the rate of increase in pollution was not very high until the end of the initial simulation. However, the reason for the increase in concentration accumulation volume can be related to the existence of permeable boundaries and severe drop of underground water in this area. In other words, when the underground water level drops too much in the saturation area of the plain, the direction of the flow will move the volume of polluted water towards the aquifer at a higher speed.

If the situation of groundwater withdrawals continues in the same way, in addition to the reduction of the groundwater storage of the plain, the quality of the remaining water storage will also decrease. This causes more serious problems in the agricultural situation of the region. The results of the implementation of quantitative and qualitative model in order to investigate the infiltration of polluted water from the landfill based on the concentration of pollution, showed that there is a high probability of the infiltration of polluted particles from the south wall side to the aquifer during periods of rainfall Event that current is run in the channels accidently. and then the expansion to the sea will actually occur due to the drop in the water level of the Caspian Sea. Water infiltration is more likely in the eastern regions than in the western regions. The reason for choosing the spread of pollution from the eastern waste disposal site in order to show the accumulation of polluted particles and the repulsion from the sea was the same. It is suggested that in the field of policy making, in order to control the plain's leachate crisis, appropriate bed construction and walling of the waste accumulation area should be applied based on the flow direction.

Identifying the number of wells in groundwater level estimation is an important step in terms of reducing the maintenance cost and saving the cost of harvesting information. Principal Component Analysis (PCA) is one of the techniques that reduces data that plays a significant role in identifying low data. In this research, the average annual groundwater level of 51 wells in Neyshabour plain with a statistical period of 10 years (2010-2019) was studied using statistical analysis of the main components of the wells to determine the level of groundwater level in this plain. Using PCA, the relative importance of each well was calculated between 0 (for completely ineffective well) to 1 (for the very effective wells). The results showed that among the 51 wells in the studied area, 27 wells are considered as wells, and the remaining wells are considered as low-level wells. By eliminating 24 less wells, the estimated ground water level error in the studied area is 26% higher than that used for all wells. Also, to take into account the factor of time, changes in this method were done in two 5-year periods. The results showed that 42 wells were selected as important well during the first 5 years period (2010-2014), which was reduced to 35 wells during the next 5 years (2015-2019).

Remediation of groundwater quality after contamination is difficult and the cost of remediation may be very high. Therefore, the improvement of water quality may not be economically possible. So, it is very important to know the areas of the aquifer that are vulnerable to pollution in order to prevent pollution and take preventive measures. In this study, using the DRASTIC method, the sensitivity and vulnerability of the Bolook Shera aquifer has been evaluated, and based on the output of the model and the quality zoning maps of the aquifer, the priority areas for protection and monitoring have been identified and the basic quality monitoring network of the aquifer has been designed. The results of the Drastic model show that the vulnerability of the Bolook Shera aquifer varies between 98 and 150. The vulnerability of this plain is in the "very low" to "moderate to high" vulnerability categories. Finally, based on the results, 20 groundwater quality monitoring stations have been determined. In locating the monitoring stations, as much as possible, it has been tried to consider the water quality changes.

The excavation of underground structures, especially water conveyance tunnels, disrupts the natural groundwater flow regime in the area around the structure and continuously reduces the hydraulic head of the groundwater; causing problems such as drying up wells, qanats and springs close to the tunnel axis. Therefore, predicting the decline of groundwater level and flow in the water resources around the tunnel axis is one of the monitoring requirements in such projects. The Kerman Water Conveyance Tunnel, with a length of approximately 38 km, is designed to supply drinking water to the city of Kerman. According to the initial field studies in the area, there are about 242 springs along the tunnel route. In this research, the method provided by Demattis was used to investigate the possibility of changing the groundwater discharge of the resources due to the excavation of the Kerman tunnel. For this purpose, factors such as fracture frequency, rock mass permeability, the tunnel overburden, the plastic zone radius around the tunnel, the distance of the springs from the tunnel, the existence of main intersection faults between tunnel and water resources, and the type of groundwater resources were evaluated. Finally, the drawdown hazard index was classified into four categories: 1) minimal drawdown 2) partial drawdown, 3) significant drawdown, and 4) complete drawdown. Based on the obtained results, 52% and 27% of groundwater resources were placed on the partial drawdown and complete drawdown classes, respectively. The rest of the groundwater resources belonged to the other categories.

The purpose of this research is to analyze the quality of groundwater in Khanmirza, Lordegan, Borujen, Ardal, and Kiar cities based on WQI and GWQI indicators based on the Iran Standard and Industrial Research Institute (ISIRI) and World Health Organization (WHO) standard. In this research, 28 samples of groundwater (wells) were collected from different places in Khanmirza, Lordegan, Borujen, Ardal, and Kiar cities from 2020 to 2022 and 10 qualitative parameters HCO3, K, pH, TDS, EC, Ca, Na, Mg, Cl, and SO4 were chemically analyzed in the laboratory. After analyzing the data, the spatial distribution map of the index was prepared for the study area by using the inverse distance weighting interpolation method. The results showed that according to GWQI and WQI indicators, most of the samples were in the good quality category. By examining the Pearson correlation between WQI and GWQI indices and the parameters used, it was found that the two parameters TDS and EC with coefficients of 0.982 and 0.989 have the highest correlation at a significant level of 1% with the WQI index. Also, TDS and Ca parameters with coefficients of 0.975 and 0.979 have the highest correlation with the GWQI index at a significant level of 1%. The results of this research have shown that the combined use of GIS, WQI, and GWQI indicators in evaluating the quality of groundwater and their spatial distribution in the studied area is useful and effective in selecting water resources for drinking purposes.

AbstractInvestigation of temporal variations of groundwater resources quality and quantity is very important for the comprehensive management of these resources. In this study, trends of the groundwater quality and quantity parameters variations of the Sari-neka plain during the period (1991-2015) were investigated. For this purpose, Mann-Kendall and Sen’s slop estimator non-parametric tests at 95% and 99% confidence levels to evaluate the trends were analyzed. The parameters used in this study were Ca2+, Mg2+, K+, TDS, Na+, Cl-, So42- in the qualitative part and the groundwater level in the quantitative part. The results for 16 quantity observation wells indicated that the trend of groundwater level for 5 observation wells was positive. 2 observation wells were negative trend and 9 observation wells were a non-significant trend. The qualitative trend analysis for 19 observation wells showed that expect Ca2+ which experienced positive trends (3 observation wells), the other quality parameters followed negative or non- significant trend.

Groundwater is one of the main sources for supplying needs, including drinking water and agriculture.With increasing human and climate pressures on groundwater resources, accurate forecasts of groundwater flow and quality for sustainable management are essential. Underground water quality modeling is a useful tool for identifying how to transfer pollutants in a the porous aquifer. These models include several parameters that are often estimated based on previous studies or expert judgment, Or in the best cases, based on Measurements in plaeses . In conclusion, the input data to the simulation models are not accurate and are accompanied by errors, so it is necessary to first define the effective and sensitive parameters relative to the outputs of the model.In this paper, a problem with the MODFLOW-2010 and MT3DMS programs was first simulated and the desired pollutant concentrations in wells were estimated according to the parameters given over a two-year period. Sensitivity analysis for time outs and Maximum concentration has been done during these two years. According to the statistical characteristics of the outputs, effective parameters are estimated on the maximum concentration and time. The results show that the effective parameters on the concentration of solute pollutants in the wells are 1 ) Reduction coefficient 2) Distribution coefficient 3) Longitudinal diffusion 4) Hydraulic conductivity 5) Transverse diffusion coefficient 6) Porosity Respectively.effective parameters on the time associated with the maximum concentration in the well operation are 1) Hydraulic conductivity 2) Distribution coefficient 3) Porosity 4) Transverse distribution coefficient 5) Reduction coefficient 6) Longitudinal diffusion.

Managing and monitoring the quantity of groundwater resources, along with assessing the intensity and direction of their flow, constitute fundamental principles for sustainable utilization of such resources. This study aims to utilize GMS software to simulate and analyze groundwater resources in Nobandegan plain, Fars, Iran. The objectives include deriving long-term variations in these resources, evaluating the water balance, and ascertaining the direction and intensity of groundwater flow.

Data related to pumping wells, observation wells, topographic features of the plain, and rainfall, among other pertinent information, were gathered using reports from Fars Regional Water Company. Subsequently, a comprehensive hydraulic model was developed to simulate, calibrate, and validate the groundwater flow within the plain. Following this, the overall trajectory and flow intensity within the plain aquifer were simulated.

The hydrograph pertaining to groundwater within the plain reveals a ~50 meter water table drop over the course of the investigation period.  The predominant groundwater flow within this plain is directed from the northern mountainous regions toward the southwestern expanses. The maximum hydraulic head is recorded at approximately 1283 meters, while the minimum stands at 1175 meters above mean sea level, indicating a 108-m drop in the aquifer water table elevation. The simulation results of the groundwater flow within the plain reveal an increased velocity in the northern regions and, to some extent, in the southern reaches of the plain. The findings of this study may be employed for groundwater quality studies on this plain.

With the aim of increasing water, food and energy productivity, this study was carried out in two stages to develop and validate a tool for evaluating agricultural management strategies in relation to the link between water, food and energy security (NEXUS). In the first part, using the WA+ water accounting framework, with the aim of analyzing the parameters of hydro climatology, the four worksheets of basic resources, evaporation and transpiration, harvesting of water resources and productivity of the Plasjan watershed were calculated and management scenarios were determined to increase productivity, and in the second part, management scenarios with The NEXUS approach were evaluated and prioritized. The results of WA+ showed that in the Plasjan basin, the high volume of evaporation and transpiration was useless. In the second part of this research, among the 4 main scenarios (48 sub-scenarios) introduced to improve productivity, the scenarios of cultivar change and irrigation treatment, change of cultivated area and rainfed cultivation with supplementary irrigation had a positive effect on water, food and energy productivity index. After prioritizing the influential sub-scenarios with the TOPSIS multi-criteria decision-making model, the sub-scenario of wheat variety 6 with full irrigation treatment had the most positive effect on water, food and energy productivity and was identified as an indicator scenario for evaluating productivity in agricultural management.

The main purpose of this article is to investigate the issue of human health due to the continuous consumption of nitrate-contaminated underground water among people of different age groups in the vicinity of Lahijan depot. Therefore, in this study, 34 groundwater samples were collected during the wet (November) and dry (September) seasons, and the main ions were analyzed in the laboratory. Nitrate concentration in the wet season varied from 18 to 30 mg/L with an average of 24.2 mg/L and in the dry season from 8 to 24 mg/L with an average of 14.5 mg/L. The amount of NPI nitrogen pollution index showed that in the wet season, 23% of the samples are healthy and 77% of the sample locations have low pollution, and in the dry season, 82% of the samples are healthy and 18% of the samples have low pollution. The noncarcinogenic risk assessment model showed that health issues are among different age groups, including infants, children, youth, adults, and the elderly. The results of the carcinogenic risk showed that in the wet season, 65% of the underground water samples and in the dry season, 18% of the samples are unsuitable for drinking by the age group of 6 to 12 months. Identified sources of nitrates include nitrate sources found in the study area, anthropogenic activities such as Lahijan landfill and village residents' waste. Therefore, periodic water inspection, health check-up and common treatment plant in rural areas are corrective measures that should be taken to reduce the severe effects of nitrate-contaminated drinking water in the study area.