مهدی سرائی تبریزی

Drought is one of the natural phenomena caused by the decrease in rainfall and reduces vegetation and increases dust. The common method of drought monitoring is based on observational data from meteorological stations and calculates a drought index. Knowing the amount and intensity of drought in a region and planning to reduce its effects is one of the most important principles of management in regional planning fight against drought. Monitoring and management of drought is a region using remote sensing data and satellite images as a suitable tool in the temporal and spatial monitoring of agricultural drought has always been  of interest to regional managers.

This study investigates the efficacy of remote sensing data and satellite images in delineating agricultural drought zones in the southern watershed of Kerman Province from 2001 to 2022. For the purpose, three indices, including the Vegetation Cover Index(VCI),Temperature Condition Index (TCI), and Vegetation Health Index (VHI), were extract from MODIS satellite images, and TerraClimate extracts data for growing season months based on remote sensing of vegetation cover from early March to late August (2001-2022), and the resulting indicators are compared with standard precipitation index (SPI) values. It was compared in one, three, six, nine-, twelve-, twenty-four-, and forty-eight-month time series. In this study, the correlation method between stations was employed to reconstruct the incomplete station data, and the stations with the highest correlation with the incomplete station were utilized for reconstruction. After organizing the data, the reconstructed information was entered into the SPIGenerator software as input, and the SPI indices for 1, 3, 6, 9, 12, 24, and 48 months were generated for the selected stations.

In this article, the results of calculating the SPI index in various time series based on the average data from existing stations and remote sensing data were analyzed. To this end, the values obtained from all satellite-based indices, including VCI, VHI, and TCI, were extracted and compared with the ground-based SPI index in 1, 3, 6, 9, 12, 24, and 48- month time series. In other words, the response of vegetation cover in the region to rainfall with 1, 3, 6, 9, 12, 24, and 48- month time legs was investigated. The result of this study shows that the VCI index has a significant correlation at a 1% level with the SPI index in all time series except for the 1-month series. The TCI index has a significant correlation with none of the time series except for the 1-month series. The VHI index has a significant correlation at a 1% level with all time series except for the 1-month,3-month, and 24-month series. Additionally, the drought indices TCI, VHI, and VCI have a positive significant correlation at a 1% level with rainfall and soil moisture.

The overall results of the analysis of the available data showed that among the studies indices, the VCI index has the highest correlation with SPI values in different time series during the growing season, with a significant correlation at the 0.01 level. Therefore, it is selected as the preferred satellite index for monitoring agricultural drought in southern Kerman Province. The results of this study provide a basis for a better understating and evaluation of drought conditions in southern Kerman Province, and can guide optimized management and provision of drinking water and agricultural resources, leading to increased and optimized agricultural production, and ultimately, proper environmental protection.

Managing water consumption and increasing water productivity by applying low irrigation methods in the agricultural sector is one of the most important measures to adapt to water scarcity. In this study, the effect of controlled and incomplete root irrigation on the physical and economic water productivity of sunflower plants was investigated in the form of randomized complete blocks. The treatments included full irrigation(FI), adjusted low irrigation(DI) and incomplete root irrigation (PRD) at two levels of 75 and 55%. The results showed that the application of PRD75 and DI75 treatments reduced water consumption by 16.52% and the application of PRD55 and DI55 treatments caused a reduction of 29.51% in the plant growth period, compared to the FI treatment. On the other hand, the effect of treatments on the physical efficiency of irrigation water on grain yield was significant at the level of 1%. The highest amount of physical productivity of irrigation water on grain yield was related to PRD75 treatment with a value of 1.275 kg/m3. The effect of the treatments on the physical efficiency of irrigation water on plant survival was also significant at the probability level of 1%. The highest amount of physical efficiency of irrigation water on plant biomass yield was related to FI treatment with a value of 4.29 kg/m3. Also, the effect of treatments on the economic efficiency of irrigation water on grain yield was also significant at the probability level of 1%. The highest amount of economic efficiency of irrigation water on grain yield was related to PRD75 treatment with the amount of 414.6 thousand rials per cubic meter. Therefore, it was recommended to use the incomplete root irrigation method at the level of 75%, due to the high physical and economic efficiency of irrigation water on seed yield, as well as saving water consumption.

Significant decline of groundwater reservoirs in all plains of the country and its adverse consequences are intensifying day by day, so the purpose of this study is to comprehensively assess the trend of favorable and unfavorable changes in the national plan to rehabilitate and balance the country's groundwater resources.

According to the purpose of this research, from all upstream documents in water science and engineering, including water resources balance reports of the country's study areas, summary reports and feedback of regional water companies in all provinces after the implementation of this national plan and extracting information from library resources and face-to-face talks with Experts from the Ministry of Energy were used.

According to the latest available information (Ministry of Energy), there are more than 858,000 active wells in the country, of which about 50 billion cubic meters are discharged for various purposes. During the last half century, as a result of depletion of groundwater resources more than the feeding of aquifers and consecutive droughts, more than 410 out of 609 study areas of the country have been banned. With the aim of balancing water withdrawal with natural discharge capacity and repairing lost groundwater reserves over a period of 20 years, the plan to rehabilitate and balance groundwater resources in 2014 was approved by the Supreme Water Council and control the average annual deficit 5.6 billion cubic meters of aquifers (leading to the water year 2015-16) have been defined and planned in the 5-year period of the Sixth Plan in the country. In this regard, the Ministry of Energy has developed an action plan at the level of provinces and study areas covered.

With the passage of a decade since the implementation of this national plan, in this study, the results of the field performance at the level of the country's provinces were extracted and compared with the annual goals. Considering the trend, it becomes clear that the extent of water governance for the protection of underground water resources is in an unfavorable situation. The results show that not supporting this plan will face the country with irreparable challenges and consequences in the not too distant future.

Hydrological models are an effective tool for managing water resources as well as understanding the impact of land use changes and climate change on the water cycle and flow characteristics. The aim of this research is to evaluate the relative performance of integrated and conceptual rainfall-runoff models AWBM, Sacramento, SimHyd and Tank in the RRL software package in simulating the daily runoff of the Fasa Bridge watershed from the sub-basins of Maharlu Lake in Fars province. 23/9/2002 to 31/12/2003 for the model warming period, from 01/01/2004 to 31/12/2014 for the calibration period and from 01/01/2015 to 22/9/2021 for the period Validation was used. After the implementation of the models, a quantitative evaluation of the simulated monthly flow values was presented for the calibration and validation stage. Then, by trial and error method and based on the characteristics of the watershed, the optimal values of the model parameters were determined in the calibration period . Comparison of statistical indicators in the calibration period for AWBM, Sacramento, SimHyd and Tank models, efficiency coefficient 0.79, -0.02, 0.6, 0.41 and determination coefficient 0.82, 0.59, 0.79, 0.41, respectively and efficiency coefficient 0.53, -0.19, -0.44, 0.002 and determination coefficient 0.65, 0.61, -0.65, -0.36  were obtained for the validation period. The calibration results for AWBM and SimHyd models show the good performance of the model in simulation of discharge. Although the results of validation for AWBM and SimHyd models have provided weaker results compared to the calibration period, they have provided acceptable results, which may be due to the recent droughts of the validation period compared to the calibration period. The results of calibration and validation for Tank and Sacramento models indicate the poor performance of the model in simulating runoff. Also, the models have a lot of error in peak discharges.

One of the effective issues on water resources quality like dam reservoirs and other water bodies is thermal stratification. For studying the stratification in reservoirs, turbulence dynamic and internal flows must be analyzed in reservoir. Because of many phenomena that effect on stratification, studying this phenomenon is possible just with use of dynamic models. In this way using numerical models beside yield measurements are unavoidable.

Due to the water usage of Yamchi dam as a drinking water and irrigation, studying the water quality has more importance, so in this research for studying the status of thermal stratification of Yamchi dam, modeling of temperature with CE-QUAL-W2 software in one year period from (May, 2015) until (April, 2016) was done. The value of observed temperature from various points of the reservoir were compared with modeled data and with the results of modeled data, variation trend of the stratification phenomena in Yamchi dam was studied.

In this research, the value of the observed temperature was in good agreement with modeled data. The results showed that the stratification phenomena happen in reservoir and lasts about 4 months in the year. This phenomenon begins at the late May and improves in July and reaches its peak in August. At last, it would end in early September. From the September due to decrease of the temperature, stratification in the reservoir is declined and Turbulence is also seen in Autumn and Winter. This turbulence continues until late May.

As a result of droughts and human interventions, the Urmia Lake basin has faced increasing unallowable withdrawal of water resources and environmental requirements share. Over the past two decades, a series of natural and human factors have gradually changed the water balance of Lake Urmia. In addition, decreases in precipitation have been the main reason for the gap between water resources and increasing water consumption in the basin, especially in the agricultural sector. In order to deal with the Urmia Lake catastrophe, a working group was formed for the Urmia Lake restoration. The working group planned and proposed solutions to reach the ecological level of the lake in three stages within 10 years through in-basin water supply and inter-basin water transfer programs. The present research, while investigating the solutions for providing the environmental water requirement of Lake Urmia using the Analytic Hierarchy Process (AHP) method, changes in the water volume of Lake Urmia in the scenarios of water transfer from the surface flow of each entering river in the lake in the years of high intensity severe to mild drought, the implementation of the approvals of the national working group to restore Urmia Lake, including a 40% reduction in agricultural consumption from the sources of dams and other rivers without dams, releasing water from dams in non-agricultural seasons, transferring water from urban wastewater and finally transferring water between the Zab basin has quantitatively been evaluated using the MODSIM simulation model. This research will help to predict the amount of transferable water in drought, normal, and drought conditions and to plan the water accounting of the Urmia catchment. 

The watershed of Lake Urmia, located in the northwest of Iran, with an area of 51,876 square kilometers, is one of the six main watersheds of the country, which is located between the provinces of West Azerbaijan, East Azerbaijan, and Kurdistan. In terms of its territorial location, the catchment area of the Zab Kochak river is in the western part of the international border with Iraq and in the catchment area of the Western Border River basin. A significant part of the Zab watershed (source of water transfer) is located outside the country and in Iraq. The route of water transfer between the basins of the Zab basin is from the place of two dams, Silweh and Kaniseeb, which after entering the Godarchai river will eventually enter the Urmia lake water body. The different solutions from the working group’s approval have been selected for developing six scenarios. Then, the Scenarios have been evaluated by the MODSIM model and AHP analysis method. The scenarios are including reducing agricultural expenses from dams in operation, saving by reducing agricultural expenses from other rivers, transferring water between basins, transferring effluent to Lake Urmia, releasing water from dams in operation to Lake Urmia. A hierarchical structure was developed with the aim of evaluating solutions to save Lake Urmia through internal sources and transfer water sources. In this structure, there are four criteria of climate, consumption, economic-social, and environmental status. Sub-criteria of drought, surface water extraction from rivers, extraction from dam sources, extraction from groundwater resources, development of agricultural lands, and ensuring the sustainability of river flow. and providing solutions for inter-basin water transfer, a 40% reduction of agricultural water consumption from surface water sources of rivers and dams, wastewater transfer, and a 40% reduction of agricultural water consumption from underground water sources in Expert Choice software, were analyzed. 

In order to evaluate the effectiveness of the defined scenarios, the simulation model was implemented for future conditions during the next 10 or 15 water years for different scenarios. The results show that the implementation of scenarios 4 and 6, will bring the largest increase in the volume of lake water, of course, with the occurrence of precipitation and proper input. Regarding the results of scenario 1 and the sameness of its results in two periods of 10 and 15 years, it can be stated because in the definition of the scenario, it is a dry year and the amount of evaporation of the lake water is more than the amount of input into the lake. There has been no increase in the lake's water volume for several consecutive years. Also, the results show that in wet and dry years, if the maximum transfer flow scenario is implemented, we will not have a flow from the Zab river to the downstream side, and it will not be accepted from the hydrodiplomacy point of view for the neighboring country in terms of influencing the use of the Dukan dam. Therefore, water diplomacy solutions are needed to reduce environmental threats. Therefore, the issue of transferring water from the Zab basin to Lake Urmia cannot be considered guaranteed in the long term due to the impossibility of reducing the outflow of water from the country to zero. 

In conclusion, in order to evaluate all scenarios to satisfy the environmental needs of Lake Urmia shows that the protection of the lake requires correcting the mistakes of the path traveled in the current and past years, and preferably with a 40% reduction in agricultural consumption from dams and other rivers, groundwater in the basin is the main supplier of Urmia Lake. Inter-basin water transfer is the next priority because the source catchment is able to transfer water in the face of droughts due to the reduction of runoff and related challenges as well as its negative economic and social effects. It will not be as much as predicted and included in the program (600 million cubic meters per year). In addition to that, water diplomacy is necessary in terms of impacting downstream transboundary uses and reducing environmental threats. The results of this research and the high costs of water supply requirements, in parallel with the investigation of controversial options and costs of inter-basin water transfer projects, macro-management of water resources towards demand and consumption management and water saving programs and the modification of water consumption patterns and the legality of the behavior of water users from within the catchment area of Lake Urmia should be low-cost, sustainable and reliable solutions.

Floods are one of the most common natural disasters, known as a major catastrophe, affecting various parts of the world, even in developed countries, which cause billions of dollars in damage to infrastructure annually and hundreds of lives. They lose themselves. Preparation of flood zoning maps for different return periods is one of the common methods used to show the potential for flood hazards. One of the basic solutions to control and reduce the destructive effects of floods is to identify floodplains in watersheds. The purpose of this study is flood zoning and simulation of hydraulic behavior of Dafeh sub-basin in Rafsanjan watershed using HEC-RAS software. The study area of ​​Defeh sub-basin is located in Rafsanjan region in the geographical coordinates of 55 1818 55 to 39 191957 east longitude and 151 2222 29 to 38 3939 عرض north latitude. The circumference of the region is 746.6 km, the maximum and minimum altitudes of the region are 4499 and 1450 meters, respectively. In this study, Google Earth and GIS software to prepare a digital model of altitude and then after sorting and formatting the input data of the HEC-RAS model for flood zoning and simulation of river hydraulic behavior And management scenarios were used. The results obtained in this study show that the amount of discharge and volume of floods from rainfall with a return period of 25 years equal to 68.1 cubic meters per second and 1150.6 thousand cubic meters.

Knowing the spatial and temporal changes in groundwater quality is one of the important issues for optimal management of groundwater resources. In this study, the hydro geochemical properties of groundwater resources in Miandoab plain (West Azerbaijan province of Iran) were investigated.

For this purpose, the data of 51 study wells during the time period (from 2014 to 2018) were used. The qualitative parameters such as the amount of Mg2+, Ca2+, Na+, K+, HCO3-, SO42-, Cl-, CO32- and the indexes such as TH (Total Hardness), TDS (Total Dissolved Solids), EC (Electrical Conductivity), SAR (Sodium Absorption Ratio) and pH were evaluated based on drinking, agriculture and industry water quality standards. Aquifer qualitative zoning maps were extracted by entering the descriptive layers obtained from the qualitative analysis in ArcGIS software and selecting the best interpolation method based on the validation technique.

The groundwater hydro chemical analysis based on the drinking water standards of the Energy Ministry indicated that the groundwater of the plain is in a relatively acceptable condition. This was also obtained from groundwater analysis by the Schoeller method. It was found that the largest areas of this plain had saline groundwater, in terms of agriculture. Industrially, sedimentation in the plain was more pronounced than corrosion.

Results showed that the aquifer quality declined from 2014 to 2017 and improved in 2018. Zoning maps showed that Miandoab aquifer has better quality and condition in the feeding areas in terms of drinking, agriculture and industry. In other words, according to the geography of the plain, the aquifer feeding areas were less vulnerable than the areas located in the evacuation areas.

Since the agricultural sector is the main consumer of water in the country, achieving sustainable agriculture without considering environmental issues may lead to risks in the long term, therefore, the quantity and quality of surface water is so important in agriculture. This research has investigated the Ares River catchment area with the aim of qualitative monitoring of surface water resources to achieve sustainable agriculture and natural resources. More than 100 collected samples from 9 stations of Aras River between Yaichi village in Azerbaijan and near Aras Dam from October 2017 to August 2018 have been investigated, classified, and evaluated using the Wilcox agricultural water quality index and Grapher software. The results of this research showed that the samples in Schuler's diagram were within the acceptable range but for drinking, other effective elements should also be investigated. The lowest amount of sodium absorption ratio was in June (1.40 mg/L) and the highest amount was in November (3.43 mg/L). Also, the electrical conductivity of water was the lowest value in June (840 µs/cm) and the highest value in October (1375 µs/cm). According to the Wilcox diagram, all the samples were in the qualitative range of C3S1 and they are considered saltwater. Despite the high level of salinity in the samples of this river, there was no significant difference in the qualitative trends of the stations during the investigated period for agricultural use, but the necessary measures should be taken in using these waters.

Human activities, the presence of salts in riverbeds and runoff, as well as pollutants carried by the air lead to the contamination of rivers as one of the main sources of water supply. In this study, the Gamasayab River was selected and sampling was conducted at 16 designated points for three-time intervals in the most polluted location with the highest pollutant levels compared to other stations after spectrophotometric testing of the samples, in different seasons of the year. The collected samples were transported to the laboratory for measurement and determination of the target pollutant levels. Then, they were simulated using natural and modified zeolite nanoparticles for the purpose of purification. In the following, using the Design Expert model and assuming two factors, pH and absorbent-to-pollutant ratio, the optimal absorption points were determined, and the theoretical absorption values were also obtained. The research results showed that the absorption efficiency for the modified sample with 0.2 M nitric acid and sulfuric acid was estimated at 77%. From the investigation of the interaction between sulfate and three other pollutants including phosphate, nitrate, and iron, which was investigated by simulating the solution and in order to neutralize the effect of other dissolved substances, it was found that phosphate and nitrate ions led to a decrease in sulfate ion absorption by the absorbent, while iron ions increased the absorption of sulfate by the absorbent. The simulation results of the proposed model also indicated that the optimal absorption point for the absorbent was at a pH of 9.6 and a D/C value of 17.01, resulting in an absorption of the pollutant by 5.86%. Finally, the Freundlich isotherm was chosen for this absorbent with a coefficient of determination of 0.92 as the superior isotherm compared to the Langmuir isotherm with a coefficient of determination of 0.79.

Iran’s groundwater resources are considered as a vital water supply for a number of reasons, and inconsiderate usage and exhausting these vital resources would bring about a severe water crisis in the country. Underground waters are usually consumed for different purposes ranging from drinking and agriculture to industry, so that the quality measures of these resources depend on the main purpose that they are intended to be used. Consequently, different standards of quality restrict the water consumption in order to reduce harmful effects of them. Furthermore, Water quality is generally an extremely important subject in water studies, and identifying and analyzing the chemical compounds in groundwater resources could be beneficial in agricultural studies. In agriculture, both water quality and quantity play 2 part, and poor quality could certainly become a primary restricting factor in water usage. This can cause undeniable farming problems and could damage the soil as well. In this regard, the necessity of providing a proper, well-planned management system for monitoring and controlling water quality is of a great importance.Over the past years, in many parts of Iran, including Jiroft, in which this study is carried out, because of some important issues such as the growing population, frequent periods of drought and inconsiderate using of the dwindling supply of groundwater, the quality and quantity of these waters are rapidly diminishing. As the livelihood of a huge number of local people who lives in the region of Jiroft, depends on agriculture, the effective management of these water resources needs better and more up-to-date information about these resources. Having such data could definitely help us to be aware of recent changes and to be able to make better, informed decisions. The main purpose of this study would be analyzing the changes of chemical parameters in underground waters of Jiroft plain.

 Hydro-chemical analysis of Jiroft’s groundwater resources for agricultural consumption is our primary goal in this research. In order to achieve this goal, we gauged and analyzed different chemical parameters including electrical conductivity (EC), total soluble solids (TDS) and acidity (pH) in 30 samples of the wells with suitable dispersal in the region in the years of 2011 and 2018. To understand the spatial distribution of suitable areas, ArcGIS 10.5 software is used and the data layers were prepared.

 The results of the Wilcox diagram show that most of the samples are in class C2-S1, which is a sign of a low salinity line and therefore they are applicable in agriculture. Besides, a limited number of samples are in class C3-S1, C3-S2 and C4-S2, which have high salinity line and are consequently ideal for irrigating the plants that are not sensitive to salinity. It is noteworthy that none of the samples has a low salinity contamination (C1-S1). Considering the fact that most of the samples in the study area are in the range of C2-S1, they could be suitable for irrigation. According to the Wilcox diagram, the quality of agricultural water in the groundwater samples in Jiroft is in a good and mostly moderate category. Our research finding shows that TDS variations is between 320 and 2048 mgL-1, and pH variations is between 6.6 and 8.6, and therefore they are ideal for irrigation purposes.

 During the statistical period, the level of water reduction is increasing; although, in some years, the number is lower. These considerable changes confirm frequent droughts and a vast amount of underground water consumption. In this situation, diminishing groundwater quality would be inevitable and if this trend continues, the quality level of these waters will be reduced gradually. In the years when water level reduction is lower than others, we can see higher level of rainfalls or even floods in which took place in the region frequently in recent years. This naturally fuels Jiroft’s aquifers and decreases the level of water reduction. According to the zoning map of the distribution of groundwater quality parameters, the Jiroft plain has a suitable quality for agricultural purposes. Only in the southwestern margin and some other parts of the plain, the groundwater quality is lower and could not be suitable for farming purposes. Overall, most areas of the plain are of good quality and suitable for agriculture.

Groundwater is an essential natural resource that is widely used to meet domestic, industrial, and agricultural needs. In recent years, the amount of withdrawal from groundwater has been more than the amount of its recharging leading to going out of balance. Since groundwater is in the ground and it is not possible to observe directly, identifying its properties is time-consuming and expensive. On the other hand, problems such as inconsistent and incomplete input information, heterogeneous aquifers, etc., have made groundwater study difficult. In many watersheds, groundwater resources are the strategic and primary source of water supply for different users. However, groundwater extraction has exceeded the amount rate of recharge in many regions around the world, resulting in harmful ecological and environmental problems, such as water level decline, water quality degradation, drying up of wells, increased pumping costs, and land subsidence. Assessing groundwater resources for their available water volume and obtaining an accurate prediction of groundwater levels (GWL) is central to sustainable management (i.e., balancing between demand and supply) of groundwater and surface water resources in a watershed. Therefore, tools such as groundwater modeling are used to solve this problem. Simulation of groundwater flow with mathematical models is an indirect approach to solving problems with lower costs than direct methods. In fact, the use of mathematical modeling is to simulate the natural conditions of the water surface with mathematical relationships. Groundwater modeling is done using differential equations, and one of the most widely used methods in solving groundwater problems is the use of finite differences and finite elements. Accordingly, the groundwater modeling system (GMS) model and the MODFLOW code were used in this research to study the Mahabad aquifer. Next, the trend of changes in the groundwater level of the range was analyzed by non-parametric tests. Accordingly, the groundwater modeling system (GMS) model and the MODFLOW code were used in this research to study the Mahabad aquifer.

The study area of Mahabad is located in West Azarbaijan province. GMS software and MODFLOW code were used for groundwater simulation. Using the information of 22 observation wells, exploitation wells information, river information, recharge, and withdrawal from groundwater, the desired model was built. . The model was run in September 2015 for the steady-state and October 2010- September 2011 for the transient state with a monthly time step. The values for hydraulic conductivity and storage coefficient were calibrated for the steady and transient states, respectively. Aquifer thickness varied from 60 to 200 m, and the cell size was considered 200 × 200 m. Rainfall infiltration, return flow, and input flows feed the aquifer. Seventeen percent of the monthly rainfall was considered rainfall infiltration that fed the aquifer. Moreover, based on the wells' primary use, return water from the wells was considered about70, 75, and 20% for drinking water, industrial and agricultural wells, respectively. The GWL is higher in the South part of the aquifer compared to other parts and, as we move from the South part of the aquifer towards its central and southern regions, the GWL declines. In conclusion, the groundwater flows from the upper South part of the aquifer towards its lower part. More exploitation wells are in the aquifer's central section, and most of their extracted water is used for urban and agricultural purposes. It was then implemented in two stable and unstable modes and its performance was evaluated with root mean square (RMSE), mean absolute error (MAE), and coefficient of determination (R2) criteria. Various statistical methods have been provided to analyze the trend of time series. Among them, non-parametric methods are more useful in the time series of hydrological variables. These methods are suitable for time series that have elongation or skewness and are independent of the statistical distribution of the time series.  In the following, the Mann-Kendall method and Sen’s slope were used to determine the trend of the groundwater level at significant levels of 90, 95, 99, and 99.9%.

The simulation results showed that there is a very good agreement between the simulation and observational data. The model evaluation criteria including RMSE, MAE, and R2 for two stable and unstable modes were calculated as 0.84, 0.63, and 0.99, as well as 0.88, 0.72, and 0.98 m, respectively. These values showed the appropriate efficiency of the model. Based on the results, the highest level of groundwater was in the south of the Mahabad aquifer and the lowest level was in the north of the aquifer.  The optimized values ​​of hydraulic conductivity, special yield, aquifer thicknesses, values ​​of exploitation wells, and aquifer transmissivity were determined from the groundwater simulation results. The results of the Mann-Kendall test showed that Haji Khosh, Gapis, and Gorg Tapeh stations had the highest downward trend. So, in these stations, the downward trend was more significant at the level of 0.99%. The Mann-Kendall Z-parameter values were positive for the Qom Qala station, which indicated the rising trend of the underground water level in this area. The results of Sen’s slope test also confirmed the results of the Mann-Kendall test. It was so that the Sen’s slope test showed that the downward slope of the three stations Haji Khosh, Gapis, and Gorg Tapeh occurs more strongly.

The results of this research showed that GMS and MODFLOW codes are suitable tools for simulating groundwater and the condition of the aquifer with proper accuracy. Also, the results of Mann-Kendall and Sen’s slope tests showed that out of 19 wells, almost 18 had a downward trend, which shows that the Mahabad aquifer is not in a favorable condition and with the increase in harvesting and decrease in rainfall, especially in recent years, its situation will worsen. The Mann-Kendall test showed that the Mahabad aquifer is in poor condition so out of the 19 investigated wells, approximately 18 wells had a downward trend in the groundwater level. The age slope estimator method also confirmed the Mann-Kendall results. Examining the obtained results exhibits that the use of new approaches for simulation provides the opportunity to manage and balance the allocation of groundwater resources effectively. Further, the use of new tools can be considered for implementing balancing scenarios related to groundwater resources.

Limited water resources and increased water demand in recent decades have caused irreparable damage to the country's water resources. One of the important components in surface water optimization and management is long-term and short-term river flow forecasts. The aim of the present study is to compare the performance of two Bayesian BN network models with probabilistic approach and MLP neural network. Then selecting the best structural model for flow prediction is another goal of the present study. Monthly meteorological data including precipitation, monthly average temperature, evaporation and. Also, the volume of water transferred from five hydrometric stations entering the Taleghan Dam from 2006 to 2018 was introduced as input data to the models. and runoff to the dam was considered as predictable. Then, with the aim of estimating the best Prediction pattern structure, Input data with different layouts were introduced to the models. In the next step, using the hydrological method of Tennant, The environmental discharge was calculated And the probability of these discharges occurring in the registration data and seventeen patterns in the Easyfit software environment was calculated. Then comparing the selected pattern according to the probability of occurrence and the criteria of the index, Nash-Sutcliffe coefficient (NS), root mean square error (RMSE) and mean absolute prediction error (MAPE) was performed. The best model in BN model with 43.3% similarity and index criteria were estimated to be -3.98, 300, 17.3 and 0.06, respectively. MLP model with 80% similarity and index criteria were introduced as -10.3, 8266, 23.9 and 122.3 in the best model, respectively. As a result, both models performed well in runoff estimation, but comparing the environmental probabilities of the two models in the top five patterns, the BN model has an acceptable accuracy . The basin was also found to be at environmental risk.

Understanding the climate and providing safe water are two critical issues in discussing climate change and water scarcity and alarm for the future.  The purpose of this study is to evaluate the SPI drought index on the trend and duration of drought in the region and its effect on river discharge and reservoir volume of the dam.  Using climate model scenarios, this trend was extracted in the future from 2030 to 2050, and its impact in the future was estimated. Therefore, SWAT software for 1994 to 2012 was used for four hydrometric stations of Gachsar, Sierra_Kelvan, Sierra_Karaj, and Pol-e-Khoab to achieve and calibrate the results of the SUFI2 algorithm in SWAT-CUP environment with appropriate bandwidth and Nash coefficients of 0.54, 0.45, 0.72, and 0.58 respectively. Also, validations for the period 2013 to 2019 were extracted 0.34, 0.38, 0.5, and 0.44, respectively. According to the results, the climate change and drought index trend indicated a decrease in river flow and increased temperature, increasing evaporation from the dam reservoir's surface. In general, the volume of the dam reservoir has decreased by about 24 to 35% based on different scenarios.  On the other hand, considering the UNESCO IWRM guidelines, examining the evolutionary trend, and changing the flow rate, it was suggested that to plan the basin and implement important policies, crisis control of three social, economic, and environmental scenarios is seriously considered in the region.

The metropolis of Tehran has seven drinking water treatment plants, which according to the water needs, ‎more than one billion cubic meters of water treated by the treatment plants are provided to the customers ‎annually. Five percent of the volume of water entering the treatment plants is converted into wastewater, ‎which is estimated at 50 million cubic meters per year. If managed in the recycling process, it will play an ‎important role in balancing water resources and preventing water loss. Therefore, this study seeks to evaluate ‎the recycling process of water treatment in the field of drinking water supply in Tehran to increase the ‎stability of water supply and demand cycle. For this purpose, in order to effectively regenerate this cycle, it ‎was evaluated in the treatment plant No. seven in Tehran with an incoming water volume of 155 million cubic ‎meters per year. In this regard, the results of evaluation of the recycling process change in the treatment plant ‎showed that by changing the wastewater treatment process and the use of polyelectrolyte, the amount of ‎effluent decreased by 95%. The results showed that the volume of effluent decreased from 7.7 million cubic ‎meters per year to 310,000 cubic meters per year, which in fact, Five percent efficiency of effluent production ‎to three tenthe of percent of effluent production in this process change. This change in the effluent system ‎produced in the drinking water treatment plant can greatly contribute to the sustainability of water resources, ‎especially groundwater, given the volume of water resources required by Tehran.‎

The rise in water demand and reduction of water quality and soil in irrigating areas, especially in dry and semi-arid areas of the world, have turned into one of the most crucial challenges for water and soil engineering in recent years. This issue leads us toward optimal quantitative and qualitative management of these valuable resources aimed at achieving economic performance and water productivity. The periodic evaporation and transpiration of the plant in the conditions of simultaneous water and salinity stress are known as one of the most important factors in the qualitative and quantitative growth of the plant yield. Applying mathematical models that simulate the relationship between field variables and yield can be seen as a useful tool in water and soil management issues in such a situation, which has the potential to ensure optimal use of the water and soil resources of any country by providing the plant's water needs and preventing its further loss.

A factorial experiment was performed in 2019 based on completely randomized blocks design with three replications in plots with an area of 9 square meters at the agricultural and animal husbandry farm of Aliabad Fashafuyeh, located in Qom province to examine the simultaneous effect of different levels of water stress and salinity on the periodic evaporation-transpiration and fresh yield of the single cross 704 forage corn cultivar. The applied treatments included the irrigation water salinity at three electrical conductivity levels of 1.8 (S0), 5.2 (S1), and 8.6 (S2) deci Siemens/meter (dS/m), which were prepared by mixing saline well water of the region with fresh (drinking) water and three water stress levels of 100% (W0), 75% (W1), and 50% (W2) of the plant's water requirement. The depth of soil moisture in the corn plant root zone was measured by the TDR device at five depths of 7.5, 12, 20, 40, and 60 cm during different growth stages of the plant using pairs of 7.5, 12, and 20 cm stainless steel electrodes.

The simultaneous water and salinity stresses, which led to the reduced amount of periodic evaporation-transpiration of the yield compared to ideal conditions (without stress), were simulated by additive and multiplicative models. The results suggested a decrease in the evaporation and transpiration with the increased simultaneous water and salinity stresses so that the amount of total evaporation-transpiration in different treatments was measured to be between 692.7 and 344.9 mm and the fresh yield was estimated between 50.4 and 3.2 tons per hectare. Also, the highest amount of periodic evaporation and transpiration in all treatments was found to occur in the development and intermediate stages, and the relative fresh yield in the W0S0 to W2S2 treatments was calculated between 66% and 100%. The results of modeling the relative yield of the crop based on the amounts of relative evaporation and transpiration of corn in different growth stages and under the different treatments of water stress and salinity, indicated that Singh's additive model and Rao's multiplicative model were appropriate, while the Minhas model was recognized to be inappropriate in this estimation.

The research results suggested the significant impact of water stress and salinity at least at the 95% level on evaporation and transpiration and the corn yield. Moreover, the effect of the sensitivity of different growth stages of the plant on the reduction of evaporation and transpiration of corn varies so that in the three treatment groups W0, W1, and W2, the highest average decrease in slope was related to the final stage (13.6%) followed by the middle stage with an average decrease of 8.4% compared to the control treatment. Therefore, the highest decrease rate in evaporation-transpiration slope has been observed in these two growth stages due to the beginning of flowering, fruit formation, and physiological ripening of seeds. These results come from the lack of sufficient water storage and increased salinity of irrigation water in the soil. Water stresses and salinity will reduce water absorption and evaporation-transpiration, and ultimately, reduce crop production due to the decreased amount and potential of water in the soil. Another finding to be mentioned is the priority of water stress compared to salinity stress in reducing evaporation and transpiration and production yield. Also, by managing water and salinity stresses in the critical stages of plant growth (especially the middle stage), which is the time of flowering and the beginning and completion of the maize production process, a significant reduction in the crop can be somewhat prevented.

Nowadays, given the human need for water, efforts to reach sustainable water resources are essential and important. The purpose of this study was to investigate the effect of water structures construction on the conservation and optimal management of water resources in Nashar basin. For this purpose, by field survey, the specifications of the construction structures and information on water resources in the area, including wells, springs and qanats, were collected. Information on water resources was obtained from the Hamedan Regional Water Department before the construction of the structures. The results showed that 856 small water structures were constructed in the watershed, of which 660 were mortar-clad inland structures, 4 were inland-china structures and 192 were gabion structures. The volume of reservoirs created by the implementation of these structures is equal to 50936 cubic meters, of which 29502 cubic meters have been filled and the empty volume that can currently reduce floods is 2143434 cubic meters. The total discharge of the three springs control watershed before the construction of the structures was 1.8 liters per second, which after construction has reached 2.15 liters per second. The average water height of wells in the region has decreased from 11 meters before ground construction to 9 meters after construction. Also, the total discharge of active qanats in the area before construction was 32.5 liters per second, which has reached 38.5 liters per second after construction. Therefore, the impact of the construction of water structures is positive and has led to an increase in water resources in the region.

Considering the decrease in rainfall and the quantitative and qualitative limitation of water resources in the Semnan Plain, and considering the drought and water shortage conditions, it is important to study and provide a solution for the optimal use of the potential and existing resources in creating sustainable agriculture. Therefore, it is necessary to choose the appropriate cultivation pattern and avoid the cultivation of crops with high water consumption. For this purpose, by compiling and completing a number of 10 questionnaires at the level of 500 hectares, in the crop year 96-97 among the farmers of the region and using the instructions for determining the water productivity in the fields of the Agricultural Research, Education and Promotion Organization of the Ministry of Jihad Agriculture regarding the determination of water productivity Two strategic crops were applied in Semnan plain, the results showed that the fodder corn plant with a physical productivity index of 5.87 kg/m3 and an economic productivity index of 11516 rials/m3 compared to the wheat plant with a yield index The physical fertility of 0.78 kg/m3 and the economic productivity index of 6055 Rials/m3 can be considered as a suitable cultivation pattern in the Semnan Plain region to increase water productivity.

The current research was conducted with the aim of identifying the weaknesses, strengths, threats, and opportunities in the operation of the Dasht Varamin Network from the viewpoint of users, experts, and managers of the network. The research tool was a questionnaire whose validity was improved by completing 30 prototypes and checking reliability under the supervision of university professors, managers, and experts in this field. Data was collected by single-stage, random, and field survey. The statistical population included the network operators, experts, and active managers. The statistical sample size was 98 through the Cochrane relationship and 105 to avoid errors. The results of the SWOT analytical model showed that with increasing information and real awareness of the users about the challenges of the network, the cost of construction and maintenance, the actions of the Irrigation Department and Water Affairs, Agricultural Jihad, and other related organizations, will encourage the users to stop confronting and having a negative attitude. Thus, they would probably have a more responsible and concerned participation and would take more effective steps in order to remove the threat, eliminate the weakness, enhance the strength, and use the opportunities. The comparative examination of the opinions of experts such as users determined opportunities more than threats, weaknesses and strengths, this shows a shared view and hope for the existing opportunities of the network. From the respondents’ point of view, the priority was to determine the competitive strategies, then, the defensive ones. Knowing the problems of the users (challenge of the administrative process, inconsistency of the sectors related to water, negative view of the government measures by considering the previous unsuccessful experiences) experts can eliminate the weaknesses and threats in order to facilitate the affairs for the water users. Activities such as promoting new methods of irrigation and agriculture and showing the successful experiences of cooperative management of water users in the network, should have pioneering and practical results.

The purpose of this study is to evaluate the balancing strategies of groundwater resources in order to adapt to climate change. Accordingly, the simulation of two parameters of precipitation and temperature in Hashtgerd region with three climatic models HadGem2Es, EC-ERATH and GFDL-CM3, was performed using three emission scenarios RCP2.6, RCP4.5 and RCP8.5. Groundwater resources are one of the most important sources of water supply in arid areas, especially in areas facing surface water shortages. This shortage, along with climate stress, has made the water resource utilization system complex. The complexities of water resources systems along with unplanned exploitation of groundwater resources and the strong dependence of operators on it have made the development of a systemic approach in water supply and demand management for development clear. Due to the decline in groundwater aquifers, management of abstraction from these resources and control of abstraction is very important and many aquifer equilibrium scenarios have been proposed to achieve this goal.

Hashtgerd study area with code 4105 is in the division of National Water Resources Management Company-Ministry of Energy located in the west of Alborz province with an area of 1170.6 square kilometers, and with alluvial aquifer with an area of 410.7 square kilometers (Figure 2). This study area is located in the northern half of the Namak Lakebasin. Kordan river, the most important surface water source of this region, originates from the northern part and after passing through the central areas of the plain, it leaves the southern part. Most of the water resources in this area are exploited by wellsAfter climatic simulation, exponential down scaling was performed using LARS-WG v6 model. After evaluating the effect of climate change in the region, in order to evaluate the quantitative status of the aquifer, simulations were performed using the MODFLOW model and the prediction of the future situation under climate change conditions was analyzed.

The results of climatic simulation showed that the simulated values in comparison with the observational data indicate an increase in average precipitation and a decrease in temperature in most months of the year. The difference between the values obtained at the statistical level of 95% indicates a significant difference and appropriateness of simulation results. On the other hand, the quantitative results of the quantification of the aquifer indicate the continuation of the aquifer decline trend and the extracted results show that the highest rate of decline is recorded in the RCP 8.5 release scenario and the lowest rate is recorded in the RCP 2.6 scenario. The rate of aquifer drop in RCP 2.6 scenario was obtained in three models between 7.8 to 8 meters, in RCP 4.5 scenario between 7.9 to 8.8 meters and in RCP 8.5 scenario between 8.5 to 9.7 meters. After evaluating the future situation, aquifer equilibrium scenarios were analyzed in order to adapt to climate change in the region using 5 evaluation strategies by evaluating the relative improvement of the aquifer. The results of balancing strategies showed that in the scenario of drinking water supply through Taleghan dam and replacement of water from wells in the region, it was determined that 20 million cubic meters of water should be allocated for Hashtgerd drinking water supply and replace 20 million cubic meters of water extracted from wells. It becomes. Accordingly, in this scenario, while transferring water and considering the return water coefficient of drinking consumption of 60%, it was determined that a volume equivalent to 32 million cubic meters of water is taken less than the aquifer. The results obtained from the application of various balancing strategies in Hashtgerd aquifer indicate that the aquifer decline continues during the forecast period until the end of the 2024-2025 water year. Examination of the simulation scenarios shows that S1 solution, which is a 15% reduction in water abstraction from the aquifer, has shown the highest efficiency in all three scenarios of climate diffusion in the aquifer. 5. and RCP2.6 will occur at 4 and 3.2 m, respectively. The results also showed that the highest degree of uncertainty in the results of the aquifer level is related to S1 solution and shows a difference of 1.15 meters in the results of diffusion scenarios. The results of this study indicate the importance and necessity of developing strategies for balancing groundwater resources in all study areas of the country, which will be more acute in the event of climate change.

Satisfaction of users in interaction with the irrigation and drainage network is one of the important concerns of executives and officials in the field of agriculture and water. The aim of this study was to identify the factors affecting water users' satisfaction in the area of Varamin irrigation and drainage network using a questionnaire by field-documentary method and random sampling. The statistical population of users and water users under the network coverage and sample size (Cochrane relationship) was determined to be 98 people. It was a questionnaire that the validity of the research tool was completed by completing 30 prototypes, and the reliability was assessed with the opinion of university professors and experts. Education, level of water ownership, positive and significant exploitation system, age, agricultural history and type of cultivation have a negative and significant effect. Receiving water, preventing frequent visits, reducing costs and optimal distribution of water in the covered lands, lack of effective inter-organizational cooperation in land consolidation and obtaining permits, insufficient irrigation and drought information, indicate the level of impact on user satisfaction.

The importance of regulating the supply and demand regime shows the need for planning in the exploitation of surface water resources. The aim of the present study is to compare the performance of two Bayesian BN network models with a probabilistic approach and MLP neural network for flow prediction. Then selecting the best structural model is another goal of the present study. Monthly meteorological data including precipitation, monthly average temperature, evaporation, and also the volume of water transferred from five hydrometric stations were introduced as input data to the models and runoff to the dam was considered as predictable. Then, with the aim of estimating the best prediction pattern structure, input data with different layouts were introduced to the models. The results of comparing the selected pattern were performed according to the criteria of the index, Nash-Sutcliffe coefficient (NS), mean square error (MSE), root mean square error (RMSE), and mean absolute prediction error (MAPE). The best model in BN model with 43.3% similarity and index criteria were estimated to be -3.98, 300, 17.3, and 0.06, respectively. MLP model with 80% similarity and index criteria were introduced as -10.3, 8266, 23.9, and 122.3 in the best model, respectively. As a result, both models performed well in runoff estimation, but the accurate BN model is much better at being prefabricated. Finally, a structural pattern with acceptable results was identified in both BN and MLP models.