جستجوی مقالات مرتبط با کلیدواژه « groundwater » در نشریات گروه « جغرافیا »

In recent years, the population growth, the increase in irrigated land and economic development have caused the increase in the demand for groundwater resources all over the world. In arid and semi-arid regions where surface water does not have a significant amount due to low rainfall and high evapotranspiration, people lives mainly depend on groundwater. As a result, it is necessary to identify the groundwater potential areas and determine its recharge areas using accurate technologies. So, the aim of this research is to compare the method of multi- influencing factors with the fuzzy method for determining the potential of groundwater in a part of Kebar-Fordo watershed, Qom city, Iran.

For this purpose, a part of Kebar-Fordo watershed located in Qom province was selected. Six factors layer, viz. slope, annual rainfall, distance from river, geology, soil, and landuse were considered and classified based on groundwater potential susceptibility in different scales. Multi-influencing factor method can determine the groundwater potential of the region by assigning appropriate weight to different effective factors. In this approach, the layers were combined in Arc-GIS after determining the weight of the layers. In the fuzzy method, the layers of six factors were converted to fuzzy based on the linear function, and then the layers were incorporated using the gamma function. Finally, the statistics of observation points and accuracy index were used in order to evaluate the models,

The slope map represents that most part of the studied area (78.56%) has a "0-1" class while "1-3", "3-9" and "9-25" slope classes could be observed in 19.97, 1.29 and 0.18% of the total area, respectively. The soil texture has a significant effect on the infiltration and percolation of the surface water movement towards the groundwater. Therefore, in this research, the soil factor has been investigated as one of the input factors to the models. Soils with high permeability are more suitable for groundwater recharge and vice versa. The soil texture of the area consists of sandy loam, loam, sandy clay loam, and clay loam textures, which cover 3.73, 90.72, 0.23, and 5.32% of the total area, respectively, with a rank of four to one  for groundwater potential. In this study, geology map showed that Qft2 formation has the largest area (88.98%) and Plc formation is in the second rank (4.9%). Qft1, Qs.d and Mur units have an area of 2.22, 2.12 and 1.10% and the smallest area belongs to OMq formation (0.68%). Also, different types of land use in the study area were agriculture, garden, rangeland, bareland, and resendential area. The land use map showed that the largest area of this area was ariculture landuse (77.18%), while garden and rangeland covered 0.07 and 6.5% of the total area, respectively. Bareland and residential area comprise 2.94%, 13.31% of the total area, respectively. Among the different landuses, agriculture and residential area have the highest and lowest ranks in groundwater recharge. The rainfall map was categorized with four classes. The classes of 140-156, 156-168, 168-182, and 182-203 mm layers include 14.15, 48.92, 21.84 and 15.09% of the total area with the rank of one to four for groundwater recharge, respectively. The map of distance from the stream was divided into four categories: "0-659", "659-1480", "1480-2675" and "2675-4939" meters, which comprise 46.33%, 34.15%, 15.72% and 3.8% of the total area, respectively. In the method of multi influencing factor, the distance from the stream (8.33%) and the geological factor (25%) were the lowest and highest weights. In this regard, the factors of rainfall, slope, soil, landuse have 20.83%, 16.67%, 16.67% and 12.5% weights, respectively. Then, the groundwater potential map was prepared through overlaying in ArcGIS and the studied area was classified into suitable and unsuitable classes. The suitable class covers 75.15% of the studied area and the unsuitable class covers 24.85% of the total area. In the fuzzy method, the unsuitable class comprises 43.63% and suitable class covers 56.37% of the area. In order to evaluate the models, the statistics of the observation points were applied which the accuracy of the multi- influencing factor and fuzzy models was calculated as 71.42 and 78.57%, respectively.

Preparation of groundwater potential map is necessary to adopt management measures of rainfall storage and groundwater recharge in arid and semi-arid regions and it can be used for sustainable management of groundwater resources. The findings of this research revealed both model's accuracy in the studied area.

Systems for assessing groundwater vulnerability are designed to protect groundwater resources from pollution. The DRASTIC method is a well-known approach for determining groundwater susceptibility. One drawback of the DRASTIC method is that it relies on expert judgment to rank parameters, which introduces uncertainty. This study used a new generation of Fuzzy Logic (FL), called the Z-number theory, to estimate the specific vulnerability of aquifers and address this uncertainty. The specific vulnerability of the Ardabil and Qorveh-Dehgolan aquifers was estimated using two scenarios: the DRASTIC parameters as inputs and nitrate concentration values as output. The vulnerability of the aquifer was also evaluated by comparing the results of the proposed models with those of the DRASTIC model, which served as a benchmark. The analysis showed that the Z-number Based Modeling (ZBM), which considered data reliability and weighted the rules appropriately, produced higher-quality results than the classic FL. In the Ardabil plain, the ZBM yielded results that were 53% better (using seven inputs) and 184% better (using four inputs) compared to the classic FL. In the Qorveh-Dehgolan Plain (QDP), the ZBM produced results that were 127% better (using seven inputs) and 311% better (using four inputs) than the classic FL. The irregularity and non-linearity of the data, such as the high coefficient of variation (CV) in the Ardabil plain compared to the QDP, may contribute to the high CV value in the plains. Therefore, in plains with high CV, the quality of the extracted Z-number-based rules may be lower.

One of the important purposes of flood spreading plans is to feed groundwater tables and increase quality of these resources. One of the most important indicators for evaluation of artificial recharge plans is to examine their impact on quality of groundwater resources. The main aim of current research is to investigate effects of implementation of artificial aquifer recharge plan (Herat flood spreading) on ​temporal changes of groundwater quality parameters in the region.

    Harat watershed area is 1413 square kilometers in south of Yazd province. The location of flood spreading sites implemented at the end of Harat basin outlet and with an area of ​​490 hectares, which includes four implementation areas. In order to investigate and evaluate the effects of flood spreading projects on groundwater resources, statistics of parameters of 17 wells were used from the area of aquifer of Fathabad affected by these projects, based on available information, parameters of calcium, carbonate, magnesium, sodium, chlorine, and total dissolved solids and salt was extracted. The wells were classified into two groups, control and affected, based on their location relative to sites and the direction of flow in waterways of area. According to length of period, in order to evaluate the impact of water withdrawals and consequently impact of sedimentation on the efficiency of the sites, the entire period was divided into two periods so that 2003-2011 is first period and 2012-2021 is second period. Minitab software was used to check linear trend of average groundwater quality parameters. For this purpose, the average of all types of quality parameters of water resources, first and second periods were entered in software and the change process for each parameter was obtained. In order to investigate temporal trend of groundwater quality parameters, Mann-Kendall test was used at 95% confidence level and Sen's slope by XLSTAT 2019 Software.

The results related to time trend of water quality factors through Mann-Kendall method and Sen's slope showed that calcium factor among nine wells located downstream of the project, three wells have no trend and the rest have a negative trend. The results of checking trend of control wells showed that calcium had a positive trend in all but one well during statistical period under review. Factors of sodium, bicarbonate and magnesium in the downstream of projects often have a negative trend and also in the control area they often show a positive trend, but factors of salinity, chlorine and total dissolved solids in the control area do not have the same situation as other factors. So that the number of wells without trend in the control range is more than the rest of the factors. This means that the condition of the aquifer in terms of three indicators is neutral and does not have a negative or positive tendency, but the investigation of trend related to affected area showed that flood spreading projects have been able to improve the status of these factors, which are part of the important factors affecting agricultural water. lead to improvement. In order to investigate effects of flood spreading projects, at the beginning and after several years, linear trending of the average factors was done in two time periods. Due to lack of data in the last of years of implementation of flood spreading to evaluate effectiveness of groundwater quality from flood spreading project, the number of available years was divided into two almost equal parts so that impact of these projects can be investigate in the initial period and after a few years. The results of linear trend of the first and second periods showed that total dissolved solids and calcium were decreasing with a high slope in the first period, but in second period and after a few years, effectiveness decreased, but it is still decreasing with a gentle slope. Bicarbonate and magnesium factor have had an increasing trend in first period, and in second period, magnesium has decreased towards a negative slope, but bicarbonate follows an increasing trend with a higher slope than in first period. In the case of other factors such as salinity, chlorine, sodium, trends are almost similar to each other. So, in the first period, they have decreased with a slight slope, but in second period, this slope has increased proportionally. This means that the infiltration of flood water through these projects has been able to improve status of all factors except for bicarbonate, but the passage of time has left different effects on the manner and extent of effect, which requires more detailed investigations.

According to results of investigations of time trend of various factors in this region, flood spreading has been able to have a positive effect on quality of groundwater. So that in determining trends of whole aquifer, except for bicarbonate factor, which had a positive trend, in other factors, there was a decreasing trend and no trend, which indicates positive effect of flood spreading on the control of quality factors. The results of this research showed that state of trend of all factors in some wells of witness area showed an increase and, in some wells, there was no trend, but in the affected area (downstream) all factors had a decreasing trend. The location of wells and distance from the waterways and flood spreading sites have a great impact on the vulnerability of wells. So that B9 well, which is located in the farthest part of the affected aquifer and is far from flood spreading sites, is among wells that had the most negative trend in most factors. Also, B3 and B2 wells are among wells that have the highest decreasing slope. Investigations showed that B9 well was located at a very short distance from the main waterway and B2 and B3 wells are also located near the distribution sites in addition to position relative to waterway and are affected by several flood distribution sites. So, distance of wells from waterway and the location of the sites can be very effective.

Groundwater management is of great importance for the sustainability of water services. Many approaches have been used for groundwater management. So far there has been no study conducted on the anti-fragility of the social-ecological system (SES) of groundwater. System anti-fragility refers to the process by which the system likes internal and external dynamics and events because it benefits from disruptions and improves its services. The aim of the present research is therefore to provide a conceptual framework for the social-ecological management of groundwater. The research method is as follows: First, the socio-ecological system of groundwater and fragility protection was defined based on the existing principles. The two models of Talib's anti-fragility and social ecology were then linked using the transfer concept. The results of the discussion on the relationship between the two models highlighted the weaknesses associated with the lack of accurate disclosure of the anti-fragility redundancy of groundwater to disturbances. Finally, an antifragile adaptive social-ecological model was constructed with one goal, three species, and three stages in the groundwater system. The purpose includes: eliminating the negative effects of disturbances and risks in the groundwater system, including methods; The energy transfer, function transfer, and element design steps included: (i) determining the effects of the disturbance rather than the disturbance and the risks themselves, (ii) formulating a transfer policy, and (iii) implementing the policy. This article not only expands the literature on groundwater management but also provides an appropriate framework for policymakers and water managers and can be helpful in groundwater planning and management.

In the last decade, subsidence is occurring as a geomorphic hazard in a large part of Iran's plains, including Mashhad plain as one of the important plains. Investigating the subsidence rate and dealing with the causes and influencing factors for risk management is very important. Radar interferometry technique is a powerful tool in estimating subsidence with millimeter accuracy using phase observations. In this paper, 2017-2021 Sentinel 1A satellite data used in order to monitor the subsidence that occurred in Mashhad plain. The results of radar interferometry studies showed that 64 cm of subsidence occurred in the study area during the statistical period.The information of piezometric wells in the collection area and their changes during the period 1991-2019 were examined in order to find the cause of subsidence. The water level of the wells has reached its maximum decrease in the studied period. The highest drop in the groundwater level has occurred in the central and southeastern regions of the studied area. The lands of the region mostly include gardens and irrigated cultivation. In general, the highest rate of subsidence has been created in areas with a sharp drop in the groundwater level, fine-grained soil texture, and high alluvial thickness.

Stochastic models will be used as a method, to study changes in time series data in the future. The purpose of this study is to analyzing the groundwater level of piezometer wells in Shiraz, simulating and short-term forecasting of its status in the future using stochastic methods. for modeling In this research, water level statistics of 14 piezometer wells that had more complete statistics from 1993 to 2019 were used and based on ARIMA model and partial autocorrelation and autocorrelation method and with evaluation of parameters and types of models and all possible patterns in terms of being static, suitable model for predicting groundwater level in each well was obtained separately. After validation and evaluation of the model, the groundwater level was predicted in the future years 2020 to 2026. The results of groundwater level forecasting in wells in Shiraz using time series models show that with assuming the consumption pattern remains constant and no noticeable change in the groundwater recharge process, during the next 7 years, on average, we will face a decrease of about 3.5 meters in the groundwater level compared to the current situation. Therefore, due to the significant drop in groundwater level in the future and the limited resources of drinking water supply in Shiraz and the need for more water in the future, appropriate decision-making for supply management and consumption management in this city, seems necessary.It is necessary to study the consumption and demand management, in order to save water and prevent its loss in the city as a basic solution.

Landslides are a critical geohazard, often triggered by seismic activity, intense rainfall, and water table fluctuations. Understanding the complex interplay of these factors is a key task in hazard assessment and mitigation strategies. This comprehensive study investigates the regional potential for water flow dynamics, displacement mechanisms, and landslide genesis. Based on a dual approach of rigorous fieldwork and meticulous laboratory analysis, approximately 5 kg of fine-grained clay and 100 kg of coarse-grained material were collected for in-depth mechanical property testing. These investigations focused primarily on assessing Atterberg limits and shear strength characteristics. The results showed a striking correlation between the water table and the site's structural integrity. In particular, the marl and alluvial layers exhibited a significant decrease in resistance, ranging from 40% to 55% and 60% to 80%, respectively, in different regions of the study area. In addition, the cohesion of the layers decreased with increasing slope steepness, resulting in a reduction in internal friction angles. This empirical evidence highlights the region's susceptibility to increased landslide risk, particularly in precipitation-induced surface water infiltration and potential seismic upheaval, such as the powerful 7.3 magnitude earthquake in Sarpol Zahab in 2017. These combined factors highlight the imminent threat of landslides and call for proactive risk management and disaster preparedness measures.

Groundwater is one of the most important water resources that is always used by humans in different sectors. The composition and chemical quality of groundwater sources are always threatened by natural factors such as climate, soil type, geology, topography, precipitation and evaporation, as well as human factors such as population growth, extensive agricultural activities, and industrial development. Hence, hydrogeochemical researches can provide very detailed information about the effect of the aquifer materials of the study area, the route of recharge and discharge, the areas of evaporation from the groundwater, the effect of surface water on the groundwater of the region, as well as its quality in various uses for decision makers. This research  was conducted to 1) compare and determine the significant difference (using the paired samples t-test) between physicochemical parameters in the statistical period under review (between wells and springs), 2) use geochemical ion ratios in order to discover the origin of ions and influencing processes that are responsible to alter the concentration of ions in the studied water resources, 3) investigate and identify the ion exchange process (normal and reverse) using chloro-alkaline indices and some hydrogeochemical graphs, and 4) identify saline water intrusion from subsurface layers or human pollution into the groundwater sources.

 In this study, 14 piezometric wells in the eastern part of Gorgan plain and 8 springs located in the heights between the cities of Ramyan, Minoodasht, Kalaleh and Gonbad were selected for hydrogeochemical study for which hydrogeochemical processes and qualitative changes of physicochemical parameters results (including Ca, Mg, Na, K, HCO3, Cl, SO4, TDS, pH and EC) were used over a period of 10 years. To compare and determine significant differences between physicochemical parameters in the statistical period under study between wells and springs, paired samples t-test and analysis of variance were performed in Minitab software. Before performing the paired sample t-test, normality of the data was checked using the Anderson-Darling test. In  paired samples t-test, if the p-value estimated by the software is greater than or equal to 0.05, with a probability of 95%, the hypothesis H0, which means that there is no significant difference between the average of the investigated treatments, is accepted and the hypothesis H1 is rejected. However, if the calculated p-value is less than 0.05, the hypothesis H0 is rejected with a probability of 95% and the hypothesis H1, which means that there is a significant difference between the averages of the investigated treatments, is accepted. Next, the maps related to the spatial changes of the groundwater parameters were plotted in the GIS environment and by using the IDW method, and then the trend of their changes in the studied area was interpreted. Aq.QA software was also used to better analyze the hydrogeochemical data and to draw the stiff and piper diagrams. Finally, to identify the factors governing changes in groundwater quality and also to investigate the relationships between variables, Gibbs diagram, ion ratios, and compositional diagrams have been used. All the mentioned graphs were prepared using Excel software.

   The spatial distribution of hydrochemical parameters showed that the concentration of most physicochemical parameters due to groundwater flow (from west to northwest) is increasing. The results of the investigation of the water type in the springs showed that magnesium bicarbonate (Mg-HCO3) is the dominant type of water in the studied springs. Unlike springs, a wide range of water type is observed in piezometric wells (Mg-HCO3, Mg-Cl, Na-Cl and Na-HCO3). Also, Ca-Mg-CO3-HCO3 bicarbonate facies and then mixed Ca-Mg-Cl-SO4 facies are the most abundant in water resources. Based on the distribution of water source samples in the Gibbs diagram, the chemical composition of all the samples, except for one sample related to the well, is controlled by the reservoir rock of springs or piezometric wells in the plain. Since the main ions show a linear relationship with TDI, it can be concluded that there is a possibility of intrusion of saline water containing sodium and chlorine ions or dissolution of halite minerals in the groundwater of the plain. The results of ion ratios showed that groundwater is recharged by dolomite, dolomite-limestone, and lime-dolomite formations associated to different geological periods is the main factor controlling hydrogeochemical parameters in the springs. But in the observation wells of the plain, in addition to the above cases, the weathering of silicates and the small intrusion of saline water into the ground water table have caused changes in hydrogeochemical parameters. The results of ion exchanges showed that the normal ion exchange process has a more effective role than the reverse ion exchange process in final concentration of main elements in the groundwater of studied water sources.

The changes in the concentration of ions in the springs are much less than the observed wells in the plain. Bicarbonate is the dominant anion in both well and spring water sources. Nevertheless, in the two wells no. 3 and 10 chloride ions prevail, which can be caused by the intrusion of saline water from the lower layers into the groundwater. Based on the spatial distribution of the physicochemical parameters, the concentration of most of the parameters in the direction of the groundwater flow is increasing due to the presence of layers with poor quality, the infiltration of urban sewage and agricultural effluents, as well as the intrusion of saline water from the subsurface layers. The investigation of the water type of the springs shows that magnesium bicarbonate is the predominant water type. Therefore, it can be concluded that the reservoir rock that recharges the springs is more than dolomite limestone. Similar to the springs, all the wells drilled on the edge of the highlands have the dominant type of magnesium bicarbonate. But by moving away from the mountain front and changing the concentration of some ions due to environmental and human factors, the type of groundwater becomes more diverse. Based on the composition graphs, it can be concluded that there is a possibility of intrusion of saline water containing sodium, magnesium, sulfate and chloride ions or the dissolution of some minerals such as halite and gypsum sulfate, especially in the groundwater of the plain. The results the ionic ratios related to the intrusion of salt water in water resources show the good quality of the groundwater and the recharge of the aquifer by limestone formations. Considering that the springs are located in the groundwater recharge area (fresh water), they are less affected by human pollution and, as a result, they have better chemical quality. On the other hand, the wells situated in the plain, due to human activities such as the excessive use of nitrogen fertilizers for agricultural products and the infiltration of urban or domestic sewage into the aquifer along with the intrusion of saline water into the groundwater in some areas of the plain show a greater tendency to become salty.

In recent years, the irreversible phenomenon of land subsidence has led to environmental hazards in various plains of Iran including Gorgan. In general, the most important activities causing this phenomenon are inappropriate groundwater withdrawal and geological factors. The research method consists of two sections: identifying subsidence areas and examining the effective factors and parameters and evaluating the impact of each. In identification section, radar interferometry technique was used to compare the phase taken from two radar sets from the same region at two different times and measurement of land surface changes over time can be achieved through interferogram, and in the effective factors analyzing section, the determination and analysis of effective parameters such as water level drop, texture and thickness of soil layers, especially fine-grained layers were investigated. The results of the satellite data analysis indicate that the region is steadily subsiding. The mean velocity map along the satellite line of sight obtained from time series analysis showed a subsidence rate of 14 mm / month (169 mm / year). The identified subsidence range is approximately eastern-western which is consistent with trends in structures such as the Caspian. Figures of water level and precipitation in this area during 2007 to 2009 show a decreasing trend despite of seasonal fluctuations, and analysis of effective parameters shows that the subsidence is due to the same drop in water level or the difference of same thickness of the fine-grained layer at different depths

Global warming and climate change are having a significant impact on the Middle East. However, the intensity of the impact is not the same everywhere. Studies on water mass fluctuations have mostly focused on national and regional scales rather than local scales. In this study, the impact of climate change on water fluctuations in the Hawraman region (western Iran) during the last two decades is investigated. This study is based on the level-2 data of GRACE and GRACE-FO missions,. In the pre-processing stage, the Hawraman’s signal is highly improved by using a filter optimization method. In addition, the spatial leakage error from neighboring water bodies is estimated. To differentiate water balance components and evaluate the results derived from gravimetry, a series of hydroclimatic models are used, including models for precipitation, surface temperature, terrestrial water storage, evapotranspiration, and canopy water content. There is an acceptable correlation between the results of the different gravimetry series, also between gravimetry and the results of hydroclimatic models.The long-term trend includes an average water decline of 6.7 mm/year, of which 2.3 mm is due to groundwater. However, the slope of decrease in Hawraman during the studied period is lower than in neighboring areas in the Middle East. Comparisons indicate on the remarkable precipitation shift (snow to rain) as the main reason of groundwater depletion. The results of the models also show that the surface temperature increased significantly during the studied period. However, the evapotranspiration component, which is affected by temperature and water availability, shows complex variations.

The phenomenon of land subsidence is one of the most important environmental hazards that have affected many plains of the country today. Jiroft Plain located in Kerman Province is also one of the areas where subsidence effects are evident. In this research, besides analyzing the spatial subsidence of Jiroft Plain and determining the extent and trend of its spread over a period of time, the effective factors in this phenomenon were investigated. For this purpose, the Sentinel-1 radar images related to the years of 2014-2022 were used. The Coherence Pixel Technique (CPT) was utilized to map the affected areas and determine the subsidence rate. The results of this method showed that the subsidence rate in Jiroft Plain had increased from 11 cm in 2014 to 13 cm in 2022. In addition, its area had increased during this period and the expansion trend had moved towards the northern areas of the plain. To analyze the causative factors of this phenomenon, in addition to studying the changes in the groundwater level of the plain and its relationship with subsidence, the roles of faults and soil thickness in creating or intensifying this phenomenon were investigated. The results showed that in addition to the uncontrolled abstraction from the aquifer, the subsidence of Jiroft Plain was affected by Sabzevaran Fault, while subsidence intensity was higher in the areas with higher soil thickness.

Land subsidence is one of the most important environmental problems that affects agriculture and urban infrastructure. In order to plan for mitigating the damages caused by land subsidence, it is necessary to identify high-risk and prone areas for this phenomenon specially in different plains of Iran. The main purpose of this research was zoning the land subsidence in Kashan aquifer using Dempster-Schafer, Weight of Evidence, Shannon Entropy, and Frequency Ratio. To conduct this research, 14 factors affecting the occurrence of subsidence including elevation, slope, slope direction, surface curvature, distance from stream, distance from fault, distance from road, lithology, land use, longitudinal and transverse curvature, water table changes, distance from mining and well density in aquifer surface were used. Then, determining 108 subsidence positions and 108 non-subsidence positions at the aquifer level, these points were randomly classified as 30% and 70% as validation data and test data, respectively. To evaluate each of the models, the ROC curve was used. The results showed that among the used methods based on the ROC curve and the amount of AUC, the Frequency Ratio method (training: 0.84 and validation: 0.89) performed best and is introduced as the best method for predicting areas with subsidence sensitivity in studied area. Shannon Entropy, Dempster-Schafer and Weight of Evidence were also ranked next, respectively. The results of this study can be used by provincial managers to reduce the damage caused by land subsidence and to determine areas with subsidence sensitivity.

Excessive abstraction of groundwater aquifers in the country has caused a sharp drop in the aquifer water level and the loss of aquatic aquifers, the effects of which is the phenomenon of subsidence. In this study, simulation of groundwater level changes in Marvdasht-Kharameh basin from a validation period and processing of a large set of raw data in Modflow mathematical model was used. The output results of sensitivity analysis of effective parameters in the calibration of Marvdasht aquifer show the maximum effect of hydraulic conductivity parameters and horizontal hydraulic conductance anisotropy and a set of linear groups of water supply network. Therefore, it is in line with the statistics of the Fars Regional Water Organization that there are wells with high discharge in these areas. According to the conditions of the aquifer, if the current operation trend continues, it is predicted that the groundwater level will drop by 15 meters during the years 2019 to 2029. Also, according to the average land subsidence, which averages 0.76 meters per 10 meters. The average land subsidence with the current harvest trend in the next ten years is predictable 114.78 cm and with a 30% increase in harvest, the rate of aquifer decline over the next 20 years is about 37 meters with an annual decline of about It is 1.9 meters. Land subsidence in this case is also predicted to be about 280 cm. Finally, according to the maps prepared from Marvdasht aquifer, due to the alluvial nature of the groundwater aquifer, the effect of water level drop can be observed from a short distance. The rate of subsidence in the southern and southwestern margins of the plain due to the low thickness of sediments and in the northern and northeastern parts of the plain due to coarse-grained sediments, is less than the central parts of the plain.

Land subsidence is commonly referred to as vertical downward movements of the earth's surface that can be accompanied by a slight horizontal vector. Land subsidence is a global problem and a morphological phenomenon. This phenomenon is affected by human activities and natural factors that may become a threat to humans and human achievements. The phenomenon of subsidence, although imperceptible and gradual, but is associated with many risks, including the creation of potholes, failure and cracking of buildings, skewing of high facilities, damage to agricultural facilities, breakage and destruction of stairs Roads and network of urban thoroughfares. Therefore, this issue affects the urban areas more, which if not addressed can lead to many human and financial losses. Accordingly, monitoring the rate of land subsidence in order to reduce the negative effects as well as controlling its development process, will be very important and it is necessary to regularly estimate the area subsidence trend. Due to the importance of the issue, in recent years, various studies have been conducted in the field of subsidence and advances in the field of remote sensing have led to monitoring the phenomenon of subsidence, unlike in the past, with greater accuracy and speed. One of the methods that has received a lot of attention in recent years is the radar interference method, which has high accuracy and speed in processing information and monitoring land surface changes, so in this study, this method is used to monitor the situation. Subsidence of cities located in Hamedan-Bahar plain has been used.

In this study, in accordance with the intended objectives of Sentinel 1 radar images (73 radar images during the period 16/01/2015 to 14/01/20120), the information of piezometric wells in the region (related to the Water and Regional Organization of Hamadan Province ) And the 30 m SRTM digital elevation model have been used as research data. Important research tools also include GMT (for radar interference measurement and SBAS time series) and ARCGIS (for mapping). This research has been done in 2 general stages. In the first stage, the amount of subsidence in the area is assessed using radar images. In order to perform this step, radar interferometry and SBAS time series method have been used. In the second stage, the annual drop in groundwater in the region is evaluated. At this stage, in order to assess the annual drop in groundwater in the region, information about 25 piezometric wells located in the study area in the period of 1375 to 1395 has been used.

The study of subsidence results in the study cities indicates that the average annual subsidence in the urban area of Hamedan was about 23 mm, the highest amount of which was related to the western regions of the city. The average annual subsidence in the urban area of Bahar was about 9 mm, the highest rate of subsidence was in the southern areas of the urban area. The average annual subsidence in the urban area of Salehabad with 6 mm was lower than other cities, but the average annual subsidence of Lalejin with 47 mm was the highest among cities. Also, in this research, information related to 25 piezometric wells (statistical periods of wells related to the years 1375 to 1695) located in the study area has been used. Examination of the level of water level drop in the studied wells indicates that these wells have faced a lot of water level drop, so the average annual drop of wells is calculated between 100 to 2070 mm. The study of the spatial status of groundwater depletion indicates that the middle areas of the study area have the highest average annual groundwater level depletion.

The results obtained from the assessment of subsidence in the studied urban areas indicate that the highest amount of subsidence occurred in the urban area of Lalejin, so that this area during a period of 5 years (01/16/2015 to 01/14 / 2020) had a subsidence between 26 and 234 mm (average annual 47 mm). In this study, the situation of groundwater resources decline has also been evaluated. The results show that the average annual drop of wells in the region is between 100 to 2070 mm, which is the highest rate of decline in the middle areas of the study area, and given that in this region, the highest rate of subsidence also occurred. Given that there is a significant relationship between land subsidence and groundwater level decline (correlation 0.7). In fact, a study of the subsidence of cities in relation to the decline of groundwater resources indicates that the city of Lalejin, due to its location in the middle of the area and the high annual rate of groundwater decline, had the highest rate of subsidence. Also, the results of evaluations have shown that in addition to the decrease of groundwater resources, constructions have also played a role in increasing the rate of subsidence, so that the city of Hamedan has faced less groundwater loss than the city of Bahar, but it had more subsidence. Considering that the highest rate of subsidence occurred in the western, southern and eastern regions of Hamedan urban area and these areas have faced a lot of physical development in recent years, so it can be said that in addition to water loss Underground, the development of construction has also played an important role in the rate of subsidence in this city.

groundwater forms part of the water cycle and is a reliable source of water for human consumption, as well as in Iran, most of the water used in the drinking, agricultural and industrial sectors is supplied from groundwater. Due to the condition of Iran, due to the deficit surface water resources, the use of groundwater resources for water supply has been considered. 

1) Use of the Radial basis function of the neural network
If a generalized regression function of the neural network, PNN / GRNN, is selected, all of the network weights can be calculated as probable. In RBF, a Gaussian transmission function is used which is similar to a ring (GRNN) One of the benefits of these networks is its rapid learning of other networks, including the multi-layered perceptron network of MLPs. The Gaussian networks of the transfer function network are of an unidentified learning type, but the output is a controlled learning type. The network is very practical in simulating hydrological and hydrological issues, due to its rapid training, generalizability and ease of use.
 
2) Use a support vector machine
  A support vector machine is proposed based on the principle of minimizing structural error. A support vector machine can be used both for categorization issues and for the estimation of functions. used a new error function called ε-insensitive for machine application in regression problems, so that this function ignores errors that are at a given distance from actual values. This function is defined as How to design a network.
In this study, the data used were 95 piezo metric wells in the Amol-Babol Plain. Data were used with a mean average of 30 years. In order to simulate the depth of the groundwater table, effective factors such transmissivity of aquifer formations, precipitation values and distance from water resources. For the design of the network, for both models, there are two classes of training and testing data. One important criterion for training a network is the number of repetitions or epoch during training. The higher the number of replays, the error decreases so that training data can be converted, which will increase the number of unsuccessful repetitions at that time. for network optimization purposes, the goal of network training is to reduce network error, which can improve the relationship between the input and output of the model. Due to the lack of specific rules for designing artificial neural networks (ANNs), various structures have been investigated to optimize the design. Select the number and type of input parameters for the model is important. For this reason, seven design input patterns are given. Which was carried out in the software of the NeuroSolutions. 

for the optimal simulation model based on all parameters and the provision of all its input data will require a great deal of time and cost, a method based on the main parameters of input (optimal inputs) is modeled and validated. it was observed that the predicted aquifer level for both models is about to its actual value.

The results obtained with the Radial basis function and the support vector machine represent this point where the support vector machine and the radial function have the ability to have approximately the same ability to predict and modeling, although generally the results of the Radial basis function are more acceptable. The results of the model test are shown. As the results of the survey are presented, among the methods implemented in the model, using effective factors such as transmissivity of aquifer formations, precipitation values and distance from water resources to predict level of level The aquifer was used. The results of the test showed that the Radial basis function of the support vector machine with a correlation coefficient of 0.82 and a mean absolute error of 1.94 is an appropriate tool for prediction of water resource management.

Reduction in groundwater volume in one hand, and resources and human activities growth on the other hand has let to water quality depletion. Therefore study and assessing water quality for various applications including agriculture and irrigation, drinking and industry is essential for the proper and efficient management of water resources and economic growth that enable sustainable economic and social development. 

In this study, the quality of groundwater for different uses was classified in Delfan plain using calcium, magnesium, chlorine, sodium, sulfate, acidity, electrical conductivity, sodium absorption ratios, total hardness and total salts of 29 deep wells for 5 years (2011-2016), and vulnerable areas in terms of drip systems implementation was identified. Delfan Plain is located at 47ᵒ 27ʹ to 48ᵒ 18ʹE longitude and 33ᵒ 50ʹ to 34ᵒ 18ʹ N latitude. This study area is 1892 km2 in average elevation of 1856 m above sea level in northwest of Lorestan province. About 1729 km2 of this area belongs to the altitudes and the rest to the alluvial zones, indicating that the area is mountainous. The aquifer of this plain has been investigated in the present study with an area of 239 km2.
In this research, different interpolation methods were used for water quality zoning. The methods used include Kriging, Inverse Distance Weighting, Global Polynomial Interpolation, Local Polynomial Interpolation and Radial Basis Function. Kriging: An estimation method based on the weighted moving average logic and ‎known as the best unbiased linear estimator‏ .‏IDW: This method is based on this fact that points that are closer have greater values than those are farther. In this method, for each measurement point, a weight based on the ‎distance between that point and the position of the unknown point is ‎considered. These weights are then controlled by the weighting power so that ‎the larger weights reduce the effect of points farther from the estimated ‎point and the smaller weights are distributed evenly between adjacent ‎points. LPI: This method considers a short range of ‎variations in the input data and is sensitive to neighborhood intervals in ‎the shared window. As the window moves and the surface values at the center of ‎each window at each point are estimated by fitting a polygon. This method has higher ‎flexibility than the local estimator method. These two methods require no ‎assumptions for the data‏.‏ RBF: The radial function is a function as Φj ‎‎(X) = Φ (X-Xj) which is dependent on the distance between x = Rd and the fixed ‎point Rd ε Xj. In this function, Φ is a continuous and dependent function of ‎each RdεΩ subunit. R represents the Euclidean distance between any pair of ‎points in the set O. This method has 5 kernel functions: Completely ‎Regularized Spline, Spline with Tension, Multiquadratic, Inverse ‎Multiquadratic and Thin Plate Spline. It is necessary to evaluate the accuracy of each method or to select the ‎appropriate parameter. There are several methods in this regard, the most ‎important one is cross-validation. In this method, comparison between observed and estimated values is carried out using specific methods.In this research, to classify water quality, Scholer, Wilcox, and Langlier saturation indices were used.Scholler diagram is one of the most importantclassifications for drinking water ‎quality. Scholler diagram is a semi-logarithmic diagram showing the concentration of ‎the major ions in meq/liter. In this graph, water is divided by the chemical parameters ‎of sodium, chlorine, sulfate, calcium, magnesium and pH for drinking purposes‏.‏ To determine the quality of agricultural water, Wilcox classification is used which is one of ‎the most important classifications in this field. In this classification, ‎agricultural water quality according to EC and SAR is categorized into four groups of good ‎quality, acceptable, inappropriate and bad‏.‏ The Langlier saturation index is used to determine the quality of water for industrial use. It should be noted that this indicator is the most important indicator of water quality ‎assessment to the implementation of drip irrigation systems because it is used in low water ‎speed systems‏.‏ 

Results and discussion

‎According to RMSE index for different interpolation methods, ordinary kriging is a suitable method for zoning SAR, Na, Cl, SO4 and LSI index. RBF method is suitable for zoning. EC, TDS, and Mg, IDW1 method is for zoning TH and Ca, and IDW2 is suitable methods for pH zoning. The combination of qualitative layers of lowland aquifer for agricultural purposes ‎showed that 4.8% of the plain is good and 82.16% of plain is in poor, while bad quality points were not found. In terms of drinking, 48.14 percent of the aquifer ‎has good quality and 9.6 percent is has poor quality. The eastern part of the aquifer generally has ‎ the best quality for drinking and agriculture purposes. According to the zoning map, this index has the highest amount of LSI in the north and ‎east areas, so there are limitations for implementing drip systems in these areas.

Conclusion‎

Assessment of qualitative maps showed that there are some limitations in some parts of the ‎plain in terms of groundwater quality for different uses. These limitations include restrictions on ‎residential development, the use of water-sensitive crops, and the implementation of ‎drip irrigation systems during corrective measures such as using acid and temperature changes. ‎Hence, operating and maintaining of this system is faces to problem. In areas with poor ‎water quality and high LSI index, it is recommended to install treatment plants to improve the ‎quality of drinking water as well as to use a proportional crop pattern compatible to available water quality such as ‎the use of salinity tolerant crops, and not use the clog-sensitive dripper.

Groundwater is one of the most important natural resources in arid and semi-arid regions. The purpose of this study is to identify areas that have groundwater capacity and to prioritize the factors affecting it. In this study, 11 indicators affecting groundwater capacity including Slope, Elevation, Aspect, Distance from River, Drainage Density, Distance from Fault, Topographic Wetness Index, and Topographic Position Index, lithology, Land use and Relative Slope Position were used. 30% of the totals of 230 wells were randomly placed in the validation data group and 70% in the training data. To prioritize the effective factors and zoning of groundwater potential in Ghorichay watershed, the random forest method was used using ArcGIS and to evaluate the model of relative performance curve (ROC) and Area Under the curve surface (AUC). The results showed that the groundwater capacity of about 8% of the watershed is higher at the outlet of the watershed. According to the VIP diagram, the TWI layer with a value of 0.329 and the distance from the river layer with a value of 0.175 was the most and the least influential factors on groundwater capacity, respectively. The area below the AUC curve showed an accuracy of 87% in the training phase to identify areas with groundwater potential. The result of this study can be used in groundwater management in the Ghorichay watershed.

Investigating the effect of drought on water resources of countries plain is high important at optimal management of water resources in the agriculture and natural resources part. The phenomenon of climate change, affects the amount of water existence in aquifer by changing amount of precipitation. The occurrence of consecutive climate droughts affects ground water resources. Knowing and awareness of the effect of time between two phenomenon of drought and hydrological drought, can help managers and planners of the water sector. Over the years, the effect of drought on ground water resources less attention has been paid. In order to understand the state of groundwater resources and optimum management, it is necessary to carry out a thorough study of groundwater fluctuations. In this research, Marand plain is the purpose of this study. Marand Plain is poor in rainfall and has a rainfall of 450 mm / year and at least 150 mm / year which varies in the plains and mountainous regions. In this research, we have tried to investigate the effect of atmospheric drops, including rainfall, on ground water level in the Marand watershed.

The Marand plain with 45 °, 15 to 50 minutes east longitude and 37 ° 7 'to 38 ° 56' north latitude and with an area of 42.517 square kilometer is one of the vast plains in the northwest of East Azarbaijan province. Which is selected as the study area. In this study, in order to study the trend of ground water level changes in the Marand Plain, the static surface data of 23 piezometric wells was used during the 2000 to 2016. First, a common statistical period was chosen to analyze the data series (2000 to 2016). Then in order to reconstruct the statistical defects, the correlation between stations and piezometric wells and linear regression method was used. The IDW method was used to calculate the average rainfall of the plain. Finally, the standard water level index (SWI) and the SPI index for the studied basin were calculated and analyzed. 

The aim of this study was to investigate the effects of climate drought on the fell of groundwater level in the Marand plain using SPI and SWI indices. Meteorological drought conditions in the Marand plain were calculated using the SPI index on a 12-month time scale. The results and drought accuracy of the rain gauge stations in the studied basin showed that during the study period, the first period of drought since 2005 started gradually with decreasing atmospheric precipitation and continued until 2007 and after a period of humidity short-term, again, a short period of drought from 2008 to 2009 has been on the ruling area. The SWI index was used to survey the status of groundwater level. This indicator also showed that in terms of time and place, the drought based on this index corresponded to the drought caused by the SPI index.

Using the SPI index, the drought trend was studied in the region. The results showed that during the study period (2000-2016) three drought periods from winter 2005 to beginning of 2009, summer of 2011 to the end of 2012 and winter of 2015 to summer of 2016 occurred. Drought affected areas included the east and center of the study area and the west of the region witnessed more atmospheric precipitation. The SWI index was used to survey the status of groundwater level. The index showed that in terms of time and place, the drought based on this index corresponded to the drought caused by the SPI index. Data analysis showed that these two indices with a time interval of one season had a correlation of 1%. This means that the hydrological drought after a season has a direct impact on the surface of the water. In general, we can conclude from the results of this study that the trend of ground water surface changes has been consistent with the drought and weathering changes in the region. Therefore, the fall of the ground water level of Marand plain can be largely influenced by weathered droughts.

Groundwater resources are the second largest freshwater source in the world after the polar glaciers. The study of groundwater fluctuations has significant importance in the planning and sustainable management of each region. The purpose of this study is to investigate the spatial and temporal changes in groundwater levels in Damghan watershed concerning land-use changes. This study is conducted using geostatistical methods and remote sensing and routing of changes using R software in the statistical period of 1994-2020.  Groundwater table data were collected for 1760 wells including deep wells, semi-deep wells, and main wells of qanats. After controlling the accuracy and quality of data and checking the data normality, interpolation was performed. The Kriging method was used for interpolation and Inverse Distance Weighting, and changes were routed using R software. Land-use changes for 2000, 2010, 2015, and 2020 were studied using remote sensing and their relationship with groundwater level changes was analyzed. The results show that the groundwater level has decreased in most parts of the basin, including the east, north, and southwest. In these areas, the groundwater level has decreased by 14.7 m, over 26 years, which means an average of 56 cm per year. Also, the most land-use changes have occurred in these areas in that the area of gardens has increased by 10016.37 hectares, urban areas have increased by 637.02 hectares, barren lands have increased by 76907.4 hectares, and surface water resources  -due to the construction of the dam - have increased by 453.15 hectares, and rangelands have increased by 30337.58 hectares, forests have decreased by 48325.86 hectares and agricultural lands have decreased by 90350.47 hectares for the time interval between 2000 to 2020.

The main purpose of this study is to investigate the groundwater level using remote sensing science and GIS and its relationship with land use. For this purpose, the relevant images were taken and the necessary pre-processing was applied on each of them. Then the images were modeled and classified. In order to study land use changes, the land use classification map for both 2000 and 2020 was used using the object-oriented classification method and then to study land use changes, the land use change map was extracted for a period of 20 years. After extracting the land use change map in order to select the best model, for 2000, the circular method for 2020, the Gaussian model, which were recognized as the most accurate method. The results showed that the 2020 land use map of the rangeland class had the most and then the residential area had the most area. Looking at the uses of the two years, the results show a significant difference that the use of gardens has decreased significantly, which indicates the lack of management and felling of trees and the destruction of forests and gardens and turning it into residential and agricultural areas and The use of the residential area also increased from 42187 to 69164 in 2000. By adapting the land use map to the groundwater level map, it showed that the highest average water level in 2000 was recorded for agricultural use at 64.50 meters and the lowest average water level was recorded for barren land use at 26.00 meters. Considering the land use map and groundwater level map of 2020, the highest average water level in this year belongs to agricultural use with 61.19 meters and the lowest average water level recorded is related to soil use with 28.00 meters. The level of water level accelerates the destruction of these natural resources and will lead to terrible dangers, the most important of which is the issue of land subsidence.