رسول میرعباسی نجف آبادی

In this study, the WEAP model was used to analyze the continuation of the existing situation (reference scenario) and the impact of implementing the defined scenarios s1 (increasing drip irrigation with 85% efficiency and sprinkler irrigation with 65% efficiency), s2 (increasing the cultivated area) , s3 (change in cropping pattern), s4 (water demand management by 20%), s5 (40% reduction of inflow to the reservoir in the planning horizon) and the combined scenarios from these scenarios for the optimal allocation of the Jiroft reservoir water. The results of the different scenarios show that in the reference scenario, the total amount of agricultural demand is 1559.8 million cubic meters, of which 19.7 million cubic meters are not supplied. According to scenario s1, the total amount of agricultural demand is 801.8 million cubic meters, which is fully met, and the amount of dam water storage in this scenario will be 66730 million cubic meters. The results also show that the amount of water demand and unmet water demand does not change in the combined scenario S145 compared to the combined scenario S14. Still, the water storage in the dam reservoir decreases by 66037 million cubic meters. The results of this study have shown that the WEAP model offers the most effective solutions to meet the varying water needs of the Jiroft Plain and reduce the negative effects of drought. Changing the current cropping pattern increases the amount of storage and the unmet water demand also decreases.

Human civilizations have always depended on freshwater to form, develop and fulfillment of various needs. With increasing urbanization, not only has the need for freshwater not diminished, but also some new technologies and industries have increased water consumption, and the pollution of water sources has increased significantly. Since groundwater resources are far from surface pollution and have their natural remediation ability, protection and remediation have not been given sufficient and appropriate attention. This issue and the overexploitation of aquifers have resulted in the quantitative and qualitative balance of groundwater resources being unsustainable. These issues show that further research is needed on various aspects of groundwater remediation. By developing the equations for water movement in porous media and analyzing them, it is possible to simulate groundwater flow. In this study, the double-well pumping system has been investigated analytically as one of the effective methods for aquifer remediation. In this system, pumping wells provide a return to natural conditions by draining polluted water and preventing it from spreading in the aquifer. For this purpose, the equations of the groundwater potential function and the stream function were determined for two pumping wells near a permanent stream. In other words, the real part of the complex potential equation represents the potential function and its imaginary part specifies the stream function; using the image well theory, the effect of the stream was also applied in the problem relations. By determining the coordinates of the stagnation points, the capture zone of the multi-well system was delineated in various configurations and the amount of stream withdrawal was also calculated. The capture zone describes the behavior and capability of the multi-well system by indicating the capture domain of discharge wells for different distances and different pumping rates. Three configurations of the remediation system are presented for two types of critical pumping rates. Under these conditions, it is possible to control the capture zone without intercepting the stream boundary and creating gaps in the extraction region at different distances of the wells with certain pumping rates. At the first critical pumping rate, the capture zone of the double-well system is tangent to the permanent stream boundary, and at a pumping rate below this threshold, groundwater pollution does not reach the surface waters. At the second critical pumping rate, capture zones of two wells merge together. Indeed, in discharges less than this critical rate, there is a distance (gap) between capture zones of the wells and pollution can enter the surface water through this gap. Also, the distance between two wells was determined in the state that both types of critical pumping rate are equal. This case shows a state of capture zone whose boundary is tangent to the stream boundary, and the capture zones of two wells are merged together. In the mentioned state, the dimensionless distance between two pumping wells (the distance between the two wells divided by their distance from the stream boundary) and the dimensionless critical pumping rate are equal to 2×0.58 and 0.33, respectively.

Drought is a natural phenomenon that occurs as a result of a decrease in the amount of precipitation in a period of time, compared to the normal or expected amount in the same period of time. Irregularity of meteorological variables, including the precipitation with a long periodicity, is affected by the phenomena that occur all over the earth with different periodicity and are known as meteorological signals. Teleconnections are a category of meteorological signals. Teleconnection refers to two regions on the surface of the earth that have a high correlation with each other in terms of climate. In addition, some low-frequency events (with long periodicity) in tropical regions also affect atmospheric patterns in higher latitudes. Since the amount of precipitation has a direct effect on recharging the aquifers, the prolongation of the drought period due to teleconnection patterns can also affect the groundwater level. Investigating the effects of the teleconnection patterns and predicting them, especially during drought periods, will be a great help for more accurate planning and management of the watershed. Since teleconnection patterns are in the category of large-scale phenomena, it is expected that the areas affected by them will be very vast. In most of the conducted studies, the relationship between drought indices and these phenomena has been done at station points. Considering the effect of local factors on the phenomenon of precipitation, point analysis can increase the uncertainty in the results. In this study, the regional average of precipitation in Chaharmahal and Bakhtiari provinces was used to calculate the drought index and to investigate its relationship with the groundwater level. Also, in order to study the role of teleconnection phenomena in creating meteorological and hydrological (groundwater) droughts in Faradonbeh and Sefiddasht plains, the relationship between the indicators of several well-known teleconnection patterns and meteorological and hydrological (groundwater) droughts has been investigated.

In order to study the meteorological drought, the monthly precipitation data of the synoptic stations of Chaharmahal and Bakhtiari province from 2000 to 2020 were used. Also, the water level measured at 19 observation wells were used to investigate the groundwater drought of the Faradonbeh and Sefiddasht plains. The Standardized Precipitation Index (SPI) and the Groundwater Resource Index (GRI) were applied to monitor the meteorological and groundwater droughts of the Faradonbeh and Sefiddasht plains, respectively. Since the stations in the study area do not have the same distribution and each station has a different effect area, the average precipitation of the Chaharmahal and Bakhtiari province was calculated by weighted average method (based on area and distance) and the regional monthly precipitation time series was used to calculate the SPI index. Also, the values of teleconnection indicators including Madden-Julian Oscillation (MJO), El Nino-Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) for the period of 1991-2021 were downloaded from the website of The National Center for Atmospheric Research and the National Center for Environmental Prediction (NCEP/NCAR). Since teleconnection phenomena have two positive and negative phases, to investigate the relationship between meteorological and groundwater drought indices with these phenomena, the correlation between SPI and GRI with teleconnection indicators has been done in several cases: Simultaneous correlation of data (correlation between all data), correlation in positive and negative phases of each teleconnection pattern (only positive phases or negative phase of teleconnection indicators were considered), calculation of correlation in each season (based on the solar calendar) separately, removing 5 dry months of the year (June to October) and calculating the correlation with a delay of one month.

The results showed that the NAO and IOD indices have the highest correlation with precipitation and SPI index, and have had the greatest impact on precipitation and drought in the study area. Also, the IOD and ENSO indices have a negative and inverse correlation with the GRI index. In general, it can be concluded that the difference in the response time of meteorological and groundwater droughts has a direct role in the extent of its influence from teleconnection events. So that the NAO phenomenon, which has a shorter periodicity than El Nino and IOD, is more significantly related to meteorological drought, which has a shorter response time, and hydrological drought, which has a longer response time, is more affected by El Nino teleconnection, which has a longer periodicity. The MJO phenomenon, which has the shortest periodicity among the studied teleconnection phenomena, had no significant relationship with the droughts of these plains.

Evaporation is a physical phenomenon by which water particles enter the atmosphere in the form of vapor from the surface of water or the surface of wet soil through receiving solar energy. Evaporation process is an essential part of the hydrological cycle and it takes place continuously in nature. The importance of evaporation estimation in water resources and agriculture studies is undeniable. The evaporation pan is used as an indicator to determine the evaporation from the water level of lakes and reservoirs all over the world due to the ease of interpreting its data. Evaporation prediction is one of the important variables in planning and managing water resources. Various models are used to predict evaporation, such as stochastic time series models, experimental models, data mining models. Due to the fact that evaporation is affected by many parameters that are non-linear, non-stationary and random and occurs in a dynamic and complex manner, the use of experimental methods to predict evaporation that is based only on weather information such as temperature, relative humidity, wind speed and solar radiation are used, the accuracy is not enough. So far, various methods have been presented to calculate and estimate evaporation, such as the water balance method and experimental methods. These methods have flaws such as the inability to generalize to other places and different climatic conditions. Therefore, researchers tried to find a way to reduce the error as much as possible. The use of machine learning models are among these methods.

In this research, two techniques of support vector machine and network with long short-term memory will be used to estimate the amount of evaporation from the pan in Kohgiluyeh and Boyer-Ahmad Province, and the results will be compared with the actual evaporation values recorded in evapotranspiration stations and some experimental methods of evaporation estimation. In order to model and estimate the amount of evaporation, daily data of parameters of pan evaporation, rainfall, wind speed, maximum and minimum temperature, cloudiness, soil temperature, maximum and minimum relative humidity, average dew point temperature, sea level pressure and actual vapor pressure has been prepared from the regional water organization for 6 stations including Yasouj, Imamzadeh Jafar, Dehdasht, Dogonbadan, Siskhet and Likk. The length of the statistical data period varies from 39 years in Dogonbadan to 14 years in Likk. In this research, two SVM and LSTM models, as well as three experimental methods of Mayer, US Civil Engineering Organization (USBR) and Ivanov were used to estimate evaporation from pans. To use the models to estimate evaporation, first the data were randomly divided into training and testing stage. 70% of the data were considered as training data and 30% of the data were considered as test data. Finally, in order to evaluate the models, the statistical indices of explanation coefficient (R2), root mean square error (RMSE) and mean absolute value of error (MAE), model efficiency index or Nash Sutcliffe coefficient (N.S) and residual mass index (CRM) were used.

The results of the SVM model show that the error values of daily pan evaporation estimation in the SVM model in the training stage vary between 1.6 and 1.2 mm per day. The efficiency coefficient also shows that the model is in a satisfactory condition in terms of estimation and forecasting ability in the Siskhet station, in a good condition in the Yasouj station, and in a very good condition in other stations. LSTM model has weaker results than SVM model. The error values in this model are higher than the SVM model and vary between 2.2 and 3 mm per day. Also, the results of the efficiency coefficient of the model (N.S) also show that this model has not provided acceptable results for estimating pan evaporation in the two stations of Sisakht and Yasouj. In part of the models test, the LSTM model also showed a weaker ability than the SVM model in most of the stations. The LSTM model has provided better results than the SVM model only in Imamzadeh Jafar station. The best result among all the stations and the two investigated models was obtained at the Dehdasht station with an error of 1.6 mm per day and a Nash coefficient of 0.87 for the SVM model. Comparison of the results of the models with 3 experimental methods of Mayer, Ivanov and USBR also showed that, except for Ivanov's method and at Doganbadan station, none of the experimental methods could simulate the daily evaporation values well.

In summary, the results of this research show that the SVM model has estimated the northern and central regions of the province with an error between 15 and 18 percent, while the LSTM model estimates the same regions with a greater error and about 22 to 26 percent. In the south of the province, the results is almost reversed and the SVM model has an error of about 19 to 21 percent and the LSTM model has an error of between 13 to 21 percent. In the east of the province, the amount of error in the estimation of pan evaporation in the LSTM model is also higher than in the SVM model. In total, the comparison of the results of two models and three experimental methods of estimating evaporation from pans in Kohgiluyeh and Boyer-Ahmad provinces showed that LSTM model is the best model for Imamzadeh Jafar station and SVM model is the best model for the other 5 investigated stations. None of the three experimental models, provided acceptable results for the province. The results of this research show that, despite the emergence of powerful models that are capable of detecting complex and non-linear behaviors of variables based on mathematical relationships that can well recognize and simulate the pattern of data variability, the use of experimental methods to estimate pans evaporation is not recommended.

The protection of groundwater resources against pollution is an important and essential issue. One of the effective methods in the treatment of aquifers is the utilization of the injection-extraction well pair system (hydraulic fence system). In this study, the remediation system of a pair of injection and extraction wells near a stream was analytically analyzed. The potential and stream functions were analyzed together with the capture and release zones of the wells in three configurations. The base flow rate (i.e. the minimum flow rate to initiate the circulation cell between the recharge and pumping wells) was calculated and analyzed in different modes. The critical flow rate (i.e. the allowable maximum flow rate for the extraction region of the pumping well without intercepting the stream) was also specified and interpreted in the configurations for the problem. In the first configuration and when the wells were located at the dimensionless distance of 2×0.4 from each other, the critical flow rate (QCR=1.07) was more than the base flow rate (QBS=0.22). In the second configuration, equality of base and critical flow rates causes a common stream line passed through the stagnation points of the recharge and pumping wells, while the stagnation point of the pumping well was tangential to the stream. In such a situation, the dimensionless value of the distance between the injection-extraction well pair and the dimensionless value of the critical flow rate (which in this case is also equal to the base flow rate) were achieved as 2×1.04 and 0.61, respectively. In the third configuration and when the dimensionless distance between the wells was equal to 2×1.2, the critical flow rate (QCR=0.59) was less than the base flow rate (QBS=0.70). According to the results, the flow rate was determined while the remediation system captured stream’s water and the conditions of entrance of the pollution into the stream from the aquifer were created. Also, the minimum flow rate was determined for the well pair system which can has full and gapless coverage against pollution.

The river flow-suspended sediment load relationship in basins due to the rivers flow and natural and unnatural changes does not lead to providing an accurate relationship, so it is necessary to use new methods for the development of this sector. Multivariate methods and simulation and modeling based on copula functions can be considered in this regard due to the consideration of data distribution. In this study, two-dimensional copula functions were used in the period of 2010-2019 in order to simulate and joint frequency analysis of river flow-suspended sediment load and estimate the conditional probabilities in the sub-basin of Qale-Shahrokh, Zayanderood Dam basin. While examining the dependence of the studied pair-variable and choosing appropriate marginal distributions, Frank's copula was selected as the best copula in joint frequency analysis of the pair-variable of discharge-suspended sediment load according to the RMSE and NSE values. By using the selected parameters, the simulation of the studied pair-variable of river flow-suspended sediment load with the probability of more than 80% was carried out in the selected station. So that with a probability of more than 80%, it is possible to estimate the amount of suspended sediment load given by the river flow in studied station. Finally, with the probabilities of 90-95% and 95-99%, it was suggested that the equation of forecasting suspended sediment load given by the corresponding river flow in the study area, which presented the efficiency of 84% and 82%, respectively, according to the Nash-Sutcliffe statistic.

The ever-growing population and the industrialization of societies have led to an increase in environmental pollution, especially water and air pollution. In recent decades, air pollution in large cities has become a serious challenge that threatens the health of society. On the other hand, the water deficiency and the drying up of rivers, lakes and wetlands have led to an increase in dust production around cities, which in turn has worsened air pollution. Climatic factors also have an impact on changes in air pollution. Precipitation is one of the phenomena that can abruptly reduce air pollution, and air quality remains in a favorable state for some time after precipitation ceases. The aim of this study is to investigate the time when air pollution returns to the conditions before the occurrence of precipitation.

Currently, air pollution in the Isfahan metropolitan area is measured at 9 air quality monitoring stations by the Transportation and Traffic Department of Isfahan Municipality. In this study, Faiz station, which is located in an area with high traffic volume in terms of vehicle traffic, was selected among these 9 stations, which are scattered throughout Isfahan. In this study, the air pollution of Faiz station was evaluated based on the concentration of pollutants according to the standards of the US Environmental Protection Agency. Finally, the influence of precipitation on air pollution in the study area was examined.

looking at the CO concentration in the air, it was observed that the maximum time of reversal of baseline pollution after precipitation is associated with the precipitation events of March 11, February 1 and March 10 with 46, 37 and 31 hours, respectively. For PM2.5 concentrations, the maximum reversibility of pollution was recorded on May 3, January 27 and January 15, with the reversibility of this pollutant to baseline pollution being 59, 51 and 49 hours, respectively. For NO2, the maximum reversibility of pollution was recorded on March 10 and 7, which respectively 64 and 47 hours after the end of the precipitation, the amount of NO2 returned to its baseline value. As for the pollutant SO2, the effect of the precipitation of November 6 on SO2 lasted until about 3 days later, so that according to the available data, the amount of SO2 is lower than the baseline pollution at all hours of November 7.

The results show that in terms of CO in the air, there was good air quality in 99% of the cases recorded at the Faiz station and average air quality in 1% of the cases, and that in terms of SO2 in air, there was good air quality in about 99.8% of the cases recorded and average air quality in about 0.2% of the recorded cases. The study of the NO2 concentration in the air showed that 98% of the recorded cases classified in good air quality and 2% in average air quality. As for PM2.5 concentration, 26% of the time was in good condition, 48% in average air quality, 18% in unhealthy air quality for sensitive groups, 7% in unhealthy air quality and 1% in very unhealthy air quality. It should be mentioned that the PM2.5 concentration reached a hazardous air quality condition in some hours. Finally, the results of this study showed that on some days the occurrence of precipitation had no significant effect on the reduction of air pollution, while on other days precipitation caused a significant reduction in air pollution and air pollution had not reached the baseline level even after 215 hours. It is possible that after the rain stopped, other factors such as wind were effective in keeping air pollution low.

The Real-time flood control operation of a reservoir system can greatly reduce human and financial losses. In this study, a model for real-time flood control operations in reservoirs under the occurrence of floods in April 2019 and the uncertainty of hydrographs of inflows is presented. The presented model includes three modules: the flood that occurred in April 2019, Monte Carlo-HEC-ResSim simulation, and uncertainty analysis. The considered uncertainty factor is the hydrograph of the input to the reservoirs and side flows to the river. A Monte Carlo-HEC-ResSim simulation was performed according to the real flood of April 2018. In order to quantify the uncertainty of the HEC-ResSim model in the simulation of the water level of the dam reservoir, two 95 Percent confidence band factors (P-factor) and the band width factor index (d-factor) were used. Based on the results of the Monte Carlo simulation, the uncertainty in the water level of Dez, Karun and Gotvand dams due to the uncertainty of the hydrograph of the inflow was 0.037, 0.107 and 0.034 Percent, respectively. Therefore, the highest and lowest uncertainty in the water level due to the uncertainty of the inflow hydrograph is related to the Karun 1 and Upper Gotvand dams, respectively. In addition, the uncertainty bandwidth of the HEC-ResSim model in simulating the water level in Dez, Karun 1, and Upper Gotvand reservoirs was 0.151, 0.407, and 0.808, respectively. Considering that the maximum allowable amount of the accepted bandwidth factor is equal to one, the uncertainty bandwidth obtained in all the parameters (including the input and output values from the reservoirs, the volume of the reservoirs and the control points downstream of the dams) is accepted. This indicates the low uncertainty of the HEC-ResSim model in reservoir exploitation operations. The 95ppu values of the observational data in the 95 Percent confidence band for the water level of the reservoirs in the three studied dams were 100 Percent. A high 95ppu value indicates that the model has a strong physical and theoretical basis. For other parameters, the 95ppu values were low due to the low uncertainty of the parameters.

Air pollution is one of the most important problems facing people all over the world today, especially in big cities. The ever-increasing population growth, as well as the increase in vehicles and the number of industrial factories in the city of Isfahan, have led to this city being considered one of the largest industrial cities in Iran. Therefore, this city is considered the second most polluted city in Iran after Tehran. The city of Isfahan faces the crisis of air pollution on many days of the year, which directly and indirectly affects all aspects of people's lives in this city. Among these impacts is the quality of rainwater in the area, which joins the surface and groundwater in the region and affects its quality. This cycle will continue and air pollution will affect the quality of drinking water, agriculture, respiratory diseases and, in a word, the health of the people in this region.

In this study, the effects of air pollution in Isfahan on the quality of rainwater in the 10th district of Isfahan city were investigated. The quality of rainwater was studied based on the World Health Organization standard for drinking water, APHA standard for running water, Chinese standard for agricultural use, and Iranian standard for drinking water and agricultural use. To evaluate the air quality of the region, the statistics of the Isfahan Meteorological Organization station were used and the meteorological parameters were analyzed based on the American Environmental Protection Agency standards.

The results showed that the EC value of rainwater is more sensitive than pH to determine the suitability of rainwater quality for drinking uses, so when considering pH, many samples have favorable quality, but when considering EC value of the same sample, the quality of rainwater is unfavorable. The results of air quality monitoring based on the amount of PM2.5 on rainy days showed that 5 days were clean, 13 days were acceptable, and 6 days were unsanitary for sensitive groups.

Isfahan urban runoff needs to be treated for drinking but it is suitable for agriculture. The results showed that the EC of rainwater is more dependent than pH to the rainfall depth. The results show that rainfall with a relatively small depth caused a significant increase in EC of stormwater. This decrease in the amount of precipitation has led to an increase in the amount of CO and PM2.5 in the atmosphere. The amount of rainfall did not affect the pH of rainwater, while with the increase of rainfall depth, the EC of rainwater has decreased significantly. In general, rainfall depth has a significant effect on EC concentration of rainwater. The results showed that in all the rainy days, the amount of CO, SO2 and O3 pollutants are in a clean state.

Reference evapotranspiration (ET0) is the maximum amount of water transpiration for a particular vegetation cover (such as grass, alfalfa, or a standard crop area). FAO 56 report emphasis, is on measuring meteorological parameters at a height of two meters above green grass. Cultivation around the station should be on a wide area and there is no shortage of water. Agricultural meteorological stations covering a certain territory around them record the same meteorological conditions as the surrounding plants. The Penman-Monteith-FAO (PMFAO) equation was proposed to calculate ET0 and the use of alternative method was not recommended. In the present research, the Hargreaves-Samani (HS) method and the PMFAO method were evaluated on daily, Monthly and yearly time steps in the ZayandehRud basin over a period of 25 years from 1995 to 2019. The results showed that in the daily time step, the difference between the two methods is large (Nash coefficient from 0.63 to 0.87). In the monthly time step, the difference is generally negligible (Nash coefficient from 0.8 to 0.96). In annual time step (Nash coefficient above 0.8), the results are very close to each other. But in different stations, the same behavior was not seen, for example, in Kabutrabad station, in contrast to East Isfahan station, almost always, ET0 by HS method is higher than PMFAO. Therefore, in practice, to use ET0 by HS method, it is recommended to verify and evaluate at least with the nearest synoptic station and PMFAO method and then use it.

The main goal of this research is management and comprehensive planning to optimally use the available water resources of Karde dam, using the WEAP model, and supply the demand in the agriculture and drinking sectors, considering the growth of their needs in the future. For this purpose, Karde Dam was first simulated in the environment of WEAP model and the model was implemented for basic conditions and seven different scenarios of development plans. According to the results obtained for the reference scenario, this dam alone does not respond to all the needs defined completely in the horizon of the project, except by applying management measures in the form of scenarios, which will reduce water consumption in different sectors of demand. Among these scenarios are demand management, increasing irrigation efficiency, using both at the same time in one scenario, changing or reducing the cultivation pattern, etc. As a result, by applying the low irrigation scenario and increasing the efficiency at the same time, it is possible to reduce the lack of water demand by 37% compared to the reference scenario, and the reservoir storage volume in this scenario increases by 25% compared to the reservoir storage volume in the reference scenario.

Because groundwater quality monitoring is very expensive and time consuming, it is necessary to find a method for estimating the hydrochemical variables with the minimum sampling. The aim of this research is to determine the optimal number of sampling wells in Khanmirza plain in Chaharmahal and Bakhtiari. For this purpose, the results of chemical sampling of 19 wells and seven water quality variables including SAR, EC, pH, TH, TDS and the sum of anions and cations for the period 1991 to 2011 were used. At the first, the best geostatistical method for drawing zones for each variable is selected. Then by means of semi-variogram curve the radius of influence of each well is calculated for each variable. According to the amount of radius overlap the minimum number of wells were determined to estimate the average of each variable in the plain. The results showed that to estimate the pH variable one sample well, for the SAR variable 3 sample wells, for the sum of anions and total cations 4 sample wells and for the variables EC, TDS and TH only 5 sampling wells are enough. The results of two-way t-test to validate the results also showed the ability of the proposed wells to properly estimate the studied variables in the plain. Therefore, it can be concluded that in special cases that require necessary and immediate information on groundwater quality in Khanmiza plain, instead of sampling from 19 wells, sampling can be done from a limited number of wells

In this study, the effect of time series decomposition of precipitation in the simulation of electrical conductivity values of the surface water in Eskandari sub-basin in the northwest of the of Zayandeh Rood Dam Basin in the period of 1990-2020 was investigated by two algorithms based on random tree and random forest. Decomposition of observation precipitation series was done using wavelet theory, Daubechies 4 and level 2. At first, the simulation of electrical conductivity values in the studied sub-basin was done using two random tree and random forest algorithms in two phases of training and testing according to the rainfall values corresponding to the electrical conductivity values on a daily scale. The results showed that the efficiency of the model was 0.67 and 0.73 in the training phase, respectively, for random forest and random tree algorithms, and the efficiency was 0.59 and 0.55 in the testing phase for the mentioned algorithms by the Nash-Sutcliffe statistic. By decomposing the rainfall series into an approximate series and two detail series and increasing the simulation dimension to 4 dimensions, the results showed that the combination of wavelet theory with random forest and random tree algorithms was able to reduce the simulation error (RMSE) of the conductivity values in the training phase compared to the random forest and random tree algorithms by about 77.5 and 54%, respectively. These numbers in the testing phase are about 10 and 22 percent, respectively.

Nowadays, due to the limited groundwater resources and increasing population, and growth of agriculture and industries, optimum operation of groundwater needs more attention. In this research, temporal and spatial changes in the quality of groundwater resources in Faradonbeh Plain located in Chaharmahal and Bakhtiari province have been investigated.

For this purpose, the time series of qualitative variables collected from 7 sampling stations (including 6 wells and one spring) in the Faradonbeh plain during a 29-year period (1991-2019) was used. The trend of changes in groundwater quality variables of this plain was investigated using the modified Mann-Kendall test (after completely removing the autocorrelation effect). Also, for each time series, the trend line slope was calculated using the Sen slope estimator. In order to draw the delineation maps of qualitative variables, Kriging method was used in the Arc GIS software. Finally, the usability of groundwater for agricultural use in Faradonbeh plain was investigated using USSL diagram.

Comparison of delineation maps of qualitative variables showed that the groundwater quality of this plain has decreased in recent years, especially in the central parts of the plain. Also, the results of he USSL diagram indicate a decrease in the quality of groundwater for agricultural uses.

Due to the expansion of agriculture lands in this plain, the overexploitation of groundwater resources and indiscriminate of fertilizers and chemical pesticides can pose a serious threat to the water resources in the region in terms of quantity and quality. Also, the use of industrial and municipal effluents for irrigation in the long-term can have adverse effects on the life cycle of this region due to undesirable changes in soil and the possibility of leakage of these pollutants into groundwater, especially in the central part of this plain.

In this study, using the copula-based approach, the simulation of the flood discharge in the Karun River has been studied. In this regard, the flood in 11/30/2008 of the Karun River was used. Using the Nakagami and generalized Pareto marginal distributions, various copula functions were investigated, and the results showed the superiority of the Clayton copula with a parameter value of . According to Clayton copula and marginal distributions, the analysis of the frequency of occurrence of the pair variable of inflow and outflow hydrographs was carried out, and the results led to the presentation of a typical curve regarding the estimation of different values ​​of the outflow hydrograph corresponding to the values ​​of the inflow hydrograph. This curve can simulate the output values ​​of the hydrograph with different probability and based on the input values. Copula-based simulation, according to the conditional density of copula functions showed that the correlation coefficient of the simulated values ​​is 7% higher than the observed values. The accuracy and certainty of simulating the output values ​​of the hydrograph was also confirmed according to the violin plot. The results of this research showed that the copula-based simulation model has a high efficiency in simulating the output flow of the flood hydrograph. The results of the copula-based simulation, based on the root mean square error and Nash-Sutcliffe statistics, showed an error rate of 35.93 cubic meters per second and an efficiency of 0.96, respectively. The conditional density used in this research led to the presentation of a proposed equation regarding the simulation of the flood hydrograph outlet under the condition of the occurrence of the flood hydrograph inlet in the study area with an efficiency of 66%.

 Dam failure and release of stored water behind the dam is one of the most important issues in dam design and it is necessary to pay attention to its occurrence and consequences. Therefore, policymakers and planners are obliged to take measures to prevent the possible dangers of breaking the dams. Among these measures, we can mention the creation of a retaining wall in the path of flood flow due to the failure of dams.

In the present study, the construction of a retaining wall in the flood flow path due to the failure of the Ghare Aghach earth dam at different distances and scenarios has been investigated. Parameters due to dam failure were determined using the BREACH model and then its information was entered into HEC-RAS software.

If the hole is created at the level of 2451 meters from the body, 18 of the 50 sections examined will collide from the right bank or the left bank, or both. At a distance of 300 meters from the dam, the water flow at a height of 1.74 meters from the right and the water flow at a height of 2.55 meters from the left shore collide. At a distance of 2200 meters from the dam, the water flows at a height of 5.15 meters from the right bank and at a height of 0.51 meters from the left bank. At a distance of 3,000 meters from the river, water rises to a height of 3.39 meters from the left side. At 3100 meters from the dam, the water flows to a height of 2.68 meters from the left bank. At a distance of 4400 meters from the river, water at a height of 1.19 meters from the right bank collides. Finally, section 4700 of the water river attacks at a height of 3.48 meters from the right bank. However, if a hole is created at the level of 2446 meters from the body of the dam, 15 of the 50 sections examined will be attacked from the right or the left bank, or both. Therefore, in this case, at a distance of 300 meters from the dam, water flows to a height of 0.8 meters from the right bank and also water flows to a height of 2.21 meters from the left bank. At a distance of 2200 meters from the dam, water flows at a height of 4.21 meters from the right shore. At a distance of 3000 meters from the dam, the water flow at a height of 2.86 meters from the left bank. At 3100 meters from the dam, water flows at a height of 2.23 meters from the left bank. At a distance of 4400 meters from the river, water at a height of 0.9 meters from the right bank collides. Finally, at a distance of 4700 meters from the location of the dam, the water flow at a height of 2.97 meters from the right shore collides.

Areas with higher probability of flooding and with priority to the construction of a retaining wall were identified. The failure of the dam at level 2451 compared to level 2446 will cause flooding of more sections on the sides of Mehrgerd river. Among the sections studied, the most water flows attack at a distance of 2200 meters and is related to the time when a hole is created at the level of 2451 meters from the body of the dam, which due to its critical location is more important than other sections and the need to construct The wall is a barrier.

Rainfall-runoff simulation is one of the most important challenges in the management of water resources in each basin, considering the climatic changes and the increase of extreme values in recent years, especially in different regions of Iran. In this study, the rainfall and runoff values in the statistical period of 1993-2019 were used regarding the rainfall-runoff simulation in the Qale Shahrokh sub-basin in the Zayandeh-Rood Dam basin. In this study, the Vine copula-based simulation approach was used to simulate and joint frequency analysis the flow discharge in Qale Shahrokh station given by the rainfall in Chelgerd, Meyheh and Marghmalek stations. By analyzing the tree sequence of vine copulas and using internal rotated copulas, D-vine copula was selected as the best copula based on the studied statistics. By using the best copula and the conditional relationship c(u4|u1,u2,u3), the flow discharge simulation was done given by rainfall of the upstream stations. The simulation results showed an error rate equal to 18.57 (m3/s) based on the RMSE statistic and the efficiency of the model was 86% based on the NSE statistic. The results of the simulation of flow discharge values given by rainfall in the upstream stations showed that the proposed approach has simulated the average of observed values with high accuracy. By considering the condition of rainfall occurrence in the frequency analysis of flow discharge in Qale Shahrokh station, the joint return period curve and the conditional probability of occurrence in this sub-basin were obtained. Using this curve, it is possible to estimate the flow discharge values of the studied station with high accuracy along with different return periods and different probability of occurrence. Considering the fact that the proposed method is based on the condition of rainfall in the region as well as the marginal distribution according to the data, it has no implementation limitations and is somehow specific to the studied region.

Groundwater resources are valuable resources to supply water for various uses in all areas, especially arid and semi-arid areas. Due to the limited resources and increasing population and the growth of agriculture and industry, the optimal use of groundwater needs more attention. In this research, the temporal and spatial variation of groundwater quality of Sefiddasht plain located in Chaharmahal and Bakhtiari province and its capability for agricultural purposes have been investigated. For this purpose, the time series of qualitative variables collected in 9 sampling stations (including 6 wells, 2 qanats and a spring) in the Plain during a 29-year period (1991-2018) was used. The trend of changes in groundwater quality variables of this plain was investigated using the modified Mann-Kendall test (after complete elimination of the autocorrelation effect). The trend line slope was also calculated for each time series using the Sen slope estimator. The results showed that groundwater quality has decreased in recent years in some places, especially in the southern parts of Sefiddasht. In order to draw zoning maps of qualitative variables at the beginning and end of the studied period, the accuracy of various geostatistical methods, including inverse distance weighting (IDW), Kriging, Co-Kriging, etc. for Sefiddasht plain was evaluated and the IDW method was selected for this plain. Comparison of zoning maps of qualitative variables at the beginning and end of the studied period showed that the groundwater quality of this plain has decreased during the considered 29 years. Finally, the usability of groundwater in Sefiddasht plain for agricultural use was evaluated using the USSL diagram for the beginning and end of the studied period. The results indicated a decrease in the quality of groundwater for agricultural use in this plain during the studied period.

Air pollution is one of the serious challenges that have been faced in recent years, especially in major cities around the world. Isfahan, as one of the metropolises of Iran, is no exception to this rule. This issue has become critical for Isfahan as a densely populated and industrial city.

In this research, the data recorded at 17 air quality monitoring stations in Isfahan have been analyzed. The stations included Ahmadabad, Parvin, Rudaki, Ostandari, Kharazi, Rehnan, Kaveh, Feiz, Mirzataher, Jey, Misaq Stadium, Farshadi, Bahonar, Enghelab, Shahinshahr, Mobarakeh and Segzai. All the statistical analyzes in this research were related to the AQI air quality index and were performed using Excel software.

The results showed that among the 17 studied stations, Ahmadabad station did not have any clean and good days during the studied period (From April 21, 2021 to March 20, 2022) and compared to other stations, the highest number of days with the condition Unsanitary is recorded at this station. It also had the highest AQI in the fall compared to other stations. Therefore, Ahmadabad station is the most polluted area in terms of air quality. The results also showed that the highest number of good and clean days was recorded in Mobarakeh and Shahinshahr stations. These two stations had the lowest amount of AQI during the study period.

The results of this study shows that areas such as Segzi and Mobarakeh, which are relatively industrial areas, have less pollution than the Ahmadabad area, which is a residential but with high traffic. Therefore, it can be concluded that the impact of pollution caused by cars in 2021-2022 was more than the pollution caused by industries.

So far, various studies on the analysis of water quality parameters have been evaluated, but less multivariate analysis of quality parameters has been done. Therefore, in this study, a new approach has been proposed to multivariate analysis of water quality parameters using Copula functions. Since water quality data is skewed and the assumption of normality is not observed in the data distribution, so using the Archimedean Copula functions in this study for quality parameters (Sar, K, Mg, Na, Ca, Cl, Ec, Ph, Tds, So4 and Th, Hco3,) can be overcome by topic. For this purpose, qualitative data of 24 observation wells in Shahrekord plain were used. Then, by Coupling (pairing) the water quality parameters and determining the superior distribution, ten Copula functions were fitted on them. The results of fitting the distributions showed that the GEV (Generalized Extreme Value) distribution function is the best distribution function over the qualitative parameters and also the results of determining the copula functions showed that in the first stage the Copula search function as a function The best Copula was identified over the qualitative parameters, and then the functions of Clayton and Farley Gamble Morgan Stern were next. The results of fitting correlation analysis showed that the highest correlation based on Pearson, Spearman and Kendal correlation coefficients is related to the parameters (Sar, Na) and (Ec, Tds) with a correlation coefficient more than 0.9. so that the results of the criteria goodness of fit for them (Root Mean Square Error (RMSE), Nash Sutcliffe Efficiency coefficient (NSE) , Akaike Information Criterion (AIC), and Bayesian Information Criterion (BIC)) was respectively RMSE = 0.031,0.036, NSE = -0.0271, -0.0351, AIC = 66,65.5 and BIC = -6.4, -6.9 Awareness of qualitative pollution of groundwater resources is one of the benefits of using multivariate analysis methods in groundwater quality studies.

Multivariate frequency analysis of hydrological phenomena by considering the dependence between the basic characteristics of these phenomena will lead to more their accurate estimation. Due to the high flexibility provided by vine tree copulas in problems with dimension greater than two. In this study the D-vine function is used to determine the four-dimensional probabilistic distribution function of main characteristics of the precipitation events of Cremona station in Italy (including maximum rainfall intensity, total rainfall depth, duration of wet period and dry period). First, due to the significant dependence between the main characteristics of precipitation events and also using their permutation, D-vine tree structures were obtained. After fitting the various Archimedean and elliptical copula families to the pair-copulas of each D-vine tree structure, the most suitable copula families were determined for fitting the pair-copulas of each D-vine structure by the maximum log-likelihood, Akaike (AIC) and Bayesian Information Criterion (BIC). Then, in order to evaluate the accuracy of the four-dimensional probabilistic distribution functions of the important characteristics of precipitation events, the mentioned functions were compared with the corresponding four-dimensional empirical copulas. Finally, the M-R-D-L four-dimensional D-vine structure according to the evaluation criteria of R2 = 0.991, RMSE = 0.031, and MAE = 0.024, was selected as the most appropriate structure for constructing of the joint distribution function of main characteristics of precipitation in Cremona station

Nowadays, global warming and climate change phenomena are considered as the most important threats to water resources and sustainable agricultural development. Due to the limitation of water resources in Iran, population growth and subsequent water demand increase, investigation of the effects of climate change on the water resources systems and agriculture is an important issue. In this study, the effect of climate change on inflow discharges to Jarreh Dam reservoir located in Zard River Basin was investigated. For this purpose, using the performance weighting method, among 20 atmospheric general circulation models (GCM), three models were chosen that were more compatible with historical data (CSIRO-Mk3.6.0, MIROC-ESM and GFDL-ESM2M). Then, precipitation and air temperature values at a height of two meters above the ground in future periods and under RCP4.5 and RCP8.5 climate scenarios were estimated. In order to rainfall- runoff simulation and estimating the inflow to the dam reservoir, the IHACRES model was applied and the daily precipitation, temperature and discharges series recorded at the Mashin Hydrometric Station in the period of 1976- 2005 were used to optimize the model parameters. After downscaling and generating the precipitation and temperature series and verifying the accuracy of the IHACRES model, the corresponding inflow discharge to dam reservoir for every climatic scenario was simulated. The results showed that the value of inflow to dam reservoir has decreased under both considered scenarios. The annual average of inflow into Jarreh Dam reservoir will decrease 27 and 40 percent under RCP 4.5 and RCP 8.5 scenarios, respectively.