مجله پژوهش آب ایران
پیاپی 36 (بهار 1399)

Municipal wastewater is the mixture of domestic wastewater, small amounts of industrial and storm water, drain water, surface infiltration, and ground water. It usually consists of a number of contaminants, such as suspended solids, biodegradable organics, pathogens, nutrients, refractory organics, heavy metals and dissolved inorganics. Direct discharge of untreated wastewater into the natural water bodies is not desirable, as the decomposition of the organic waste would seriously deteriorate the water quality. In addition, communicable diseases can be transmitted by the pathogenic microorganisms. Nutrients such as nitrogen and phosphorous, along with organic material when discharged to the aquatic environment can also lead to excessive growth of undesirable aquatic life when discharged in excessive amounts on land can also lead to the pollution of groundwater. For these reasons, treatment of wastewater has become necessary for the protection of the environment keeping in view public health, economic, social and political concerns. In recent years, various methods for eliminating pollutants have been investigated, in which the electrocoagulation process with proper removal efficiency and low sludge production is considered as one of the newest and most desirable methods. The purpose of this study was to evaluate the efficiency of removal of COD, BOD5 and Coliform bacteria from wastewater of Urmia refinery using electrocoagulation method and optimization of the process. To do so, the effect of different parameters such as time of electrolysis, current density, pH, flow rate and conductivity of solution was investigated. This experimental study was carried out in an electrochemical recirculating tubular reactor with an iron pipe as the cathode and some iron rods inside it as the anode. In order to sampling, the inlet of Urmia wastewater refinery was considered. In order to increase the electrical conductivity of the aqueous solution, sodium chloride was used as the electrolyte. After performing the electrochemical reactions, the treated wastewater was evaluated for clotting and COD and BOD5 analysis. To determine the characteristics of the sludge the SEM and BET analysis was done. Results showed that, increasing the time of electrolysis increases the amount of metal and hydroxide ions produced in the anode and cathode of electrochemical cell. Therefore, with the large amount of hydroxide flocs, the removal efficiency increases. With an increase in current density, the rate of removal increased, and then it did not change significantly, so it can be probably said that there is a limit for the rate of adsorption of pollutants to the flocs. It has been established that the effluent pH is one of the important factors influencing the performance of electrocoagulation process. The maximum removal was observed at a pH around of 7; considering the nature of the reaction between ferrous and hydroxide ions, this was not unexpected. When pH is lower than 4, Fe(OH)3 is in its soluble form (Fe+3), and when it is higher than 6, Fe(OH)3 is in its soluble form of Fe(OH)4-. Since Fe(OH)3 has a major role in removing dye, when pH is 7, the rate of dye removal is the highest. With an increase in electrolyte concentration, electrical conductivity of the solution increases, and the voltage needed for accessing a certain value of electric current density decreases; less electric energy is also consumed. With an increase in the rate of the flow passing through the reactor, the removal efficiency decreases because the high flow rate of circulation of the solution in the reactor causes decrease in retention time of the solution in the reactor; therefore, the solution is not treated completely. The released cations from the electrocoagulation process lead to infertility of the negative electrical charge produced by the cell wall of the bacterium. The final optimum conditions during electrolysis time 40 min, the current density 7.036 A/m2, pH 7.8, conductivity of solution 1477 ms/cm and flow rate 1.97 L/min was obtained. In these conditions the removal efficiency 93% of COD, 94% of BOD5 and 100% for Coliform bacteria was determined, which is completely agreeable with the environmental standards. As it is evident, the size of the constituent particles of the sludge as a cluster is about 0.1 micrometer. Based on the results of BET analyses, the specific surface area, total pore volume, and mean pore diameter of the sludge are 56.4 m2/g, 0.27 cm3/g, and 19 nm respectively.

Approximately 94% of the total renewable sources of water is allocated to agricultural. Total irrigation efficiency in this section is estimated to of less than 43%. By using of new Irrigation methods, water consume efficiency can be increased. Correct selection of irrigation system is an important section in optimal operation of water resources. The necessity to pay attention to the characteristics and limitations of irrigation systems, the physical and chemical properties of water and soil, the environmental, economical and social Consequences, cause the selection of irrigation system become a relatively complex problem. One of the pressurized irrigation methods is semi-portable sprinkler irrigation systems. These systems have not been evaluated in some areas of Markazi province. Also, in some areas such as Arak plain that had been previously evaluated, due to the long time span and also increasing of area under cultivation, re-examination is needed. So, the performance of 10 semi-portable sprinkler irrigation systems was investigated in Arak, Shazand, Khondab and Kamijan areas.

This research includes collecting basal information, field measurements and software calculations. To determine the wind speed and direction during the test, anemometer was used. To determine the soil moisture, chemical and physical properties, samples was taken and sent to laboratory before experiment. All field testing were carried out during irrigation and also windless or low wind speed days. In each test, hydraulic variables of system, such as pressure of sprinklers, were measured at the time of performance. a pressure gauge was installed on next raiser and pressure was measured instantaneously to Increase Accuracy. The flow rate of the sprinklers was also measured by volumetric method using two hoses, a 20 Liter gallon and a chronometer. For more Accuracy, the flow rate of each sprinkler was determined from the catalog data of each sprinkler. It has been attempted to select the location of the sprinklers in points where pressure is moderate. The water collecting cans, all 15 cm in height and 15 cm in width, were placed in a 3 * 3 meter mesh. Then after an hour of operation, system was shut down and the water inside cans was measured using a calibrated measuring cylinder and was written in a form. After field operations and collecting of required data, computational operations were performed to determine the technical evaluation parameters of the system. The evaluation parameters in this study include Coefficient of Uniformity (CU), Distribution Uniformity (DU), Application Efficiency of Low Quarter (AELQ) and Potential Efficiency of Low Quarter (PELQ), that calculated for both testing block and Total system.

The results of evaluation in 10 systems indicate that due to inappropriate design and implementation, all of the evaluation parameters are less than allowed range (81% ≥ 81% CU and 81% ≥ 67%), but also Mismanagement is effective. In all of these systems, due to lack of precipitation and depletion of groundwater surface, farmers use deficit- irrigation, which Equality of application and Potential efficiency prove this. On the other hand, exception of KF system, in all systems, the number of simultaneous sprinklers in operation is increasing compared to those in the approved design, which is one of mismanagement that leads to decrease of pressure and Spray radius can't be estimated that caused in lack of distribution uniformity and resulting in inadequate irrigation in some areas and deep penetration losses in other areas. Increasing the number of simultaneous water sprayer in operation is a significant Objection. The actual efficiency of 37.9% in KHH2 to 63.8% in the KHN system was calculated. Changes in pressure varied from 13% in the KHH2 to 43% in the KM system. The average discharge varied from 1.7 L/s in KHF to 2.88 L/s in KF system and spray losses were estimated from 5.5% in the KHN to 32% in the KHF system. Distribution uniformity in the test block varied from 47% in the KF to 71% in KHN and Coefficient of Uniformity varied from 58% in KHH1 to 83% in AG system. Distribution Uniformity in all system varied from 44/3% in KF to 68/5% in SHJ system. The Potential Efficiency of Low Quarter of the test block varied from 39.5% in KHH2 to 67.3% in the KHN system and in whole system varied from 37.9% in the KHH2 to 63.8% in KHN system. The Application Efficiency of Low Quarter of the test block varied from 39.5% in KHH2 to 67.3% in KHN system and in whole system varied from 37.9% to 63.8%. In conclusion, according to the results of this study, semi-portable sprinkler irrigation systems in plains of the Markazi province are not in good condition and have various design and implementation problems.

In Iran, pressurized irrigation systems is increasing. One of the requirements of pressurized irrigation systems is to supply energy to pump water. Because of non-renewal, extraction costs and environmental hazards of fossil fuels, solar energy utilization has become inevitable. Solar energy is one of the most important and cleanest forms of new energies which can return the initial cost of solar system to a customer in the long term. One of the reasons for Iran's failure to use a large part of its cultivated land is a large distance from the national electricity network and high electricity costs. In this study, solar and electric pumps were compared economically to pump water in nine gardens under drip irrigation networks including three crops: pistachio, almond, and walnut. The gardens are located in two provinces of Tehran and Hamedan.

The drip irrigation system is applied in these gardens. The gardens were classified into three groups: small (less than 5 hectares), medium (5 to 60 hectares) and large (more than 60 hectares). First of all, pumping station was designed and then investment costs were estimated for all the studied gardens. To design and simulate photovoltaic system, the Lorentz solar pump special design software was used. It is assumed that electricity would supply for these areas in two ways including 1) installation of photovoltaic systems in remote areas without a national electricity grid 2) electricity transmission through the construction of transmission lines and trans-installation. These two conditions were compared by the present value method at two interest rates, 5 and 10%. To convert future costs to present value, real interest rate index is required. Considering the difference between the useful life of equipment for electric pumps and solar pumps, as well as solar panels, the lifetime of the projects was considered unequal in calculating the current value.

The results showed that the utilizing photovoltaic pumping without distances from the electricity distribution network is only economic in 60 ha pistachio garden with an interest rate of 10%. In the walnut garden with medium size, with the same interest rate, despite the slight difference in investment cost, it is not different with electric pumping. In the case of distance from the power distribution network, photovoltaic pumping will be more economical by reducing farm size (less capacity and pressure) and increasing the distance from the power distribution network. Of course, other factors such as temperature, sunshine, radiation intensity and solar angles may also affect photovoltaic pumping during different seasons. The results also showed photovoltaic pumping of irrigation system is economic for small and medium pistachio and walnut gardens, at 0.5 kilometres of the electric distribution network, in the interest rate of 5% and 10%. With increasing distance from the electricity distribution network, only the cost of transferring power lines to electric pumping costs increase and the use of photovoltaic pumping is more justifiable. Changes in the current value of costs for both pumping methods at a rate of 10% relative to the 5% interest rate will lead to cost reductions. In remote areas, which it is difficult to access to electricity distribution and transmission networks, the use of photovoltaic pumping is reasonable and economical. For each area, there is a specific distance from the electric distribution network which photovoltaic pumping is reasonable for drip irrigation.

Construction of dams on limestone formations, however morphologically, has an appropriate form; but usually causes seepage from the reservoir to the downstream. Also, the construction of a dam on calcareous-karst formations has the risk of over seepage from the reservoir, and the existence of the karst leads to complicating this issue. Therefore, various methods of hydrogeological analysis are needed to determine the condition of karstification of reservoir and dam axis in the karstic areas. Beheshtabad dam is in investigation studies stage and approximately situated at the far end of the anticline axis named Sangwill, which composed of dolomitic limestone with roughly 700 meters thickness. The right side of the reservoir is mainly in direct contact with this karstic formation. Hydrogeological analysis for determining the reservoir’s seepage in right side are including measurement of water level and boreholes hydrochemical analysis, measuring springs discharge and hydrochemical condition of springs and environmental isotopic studies. The results showed that karstic aquifer’s water level on the right side of the reservoir has very similar fluctuations with a difference between the minimum and maximum of 2.5 to 3 meters. The water level from the northern limb with a level of about 1625 decreases towards the spring in the southern limb with a level of about 1595 and a gradient of about 0.007. Also, spring discharge in the sought limb has the same fluctuation with three coefficients of recession curve. Recession curve coefficient α1 in the order of 10-2 indicates the intermediate flow (diffuse-conduit) make up 15% of the flow and the coefficients α2 and α3 in order 10-3 indicate the diffuse flow accounts about 85% of the aquifer flow. Hydrochemical and isotopic parameters of springs and boreholes also have low fluctuations. These variations for anions and cations are less than 20% and for Ec and acidity are less than 5%. The amount of environmental isotopes in springs and boreholes does not show any significant variations so that the standard deviation obtained from monthly acquired data is less than 1.2 per mil for δD and less than 0.2 per mil for δ18O. The amount of environmental isotopes shows that the source of springs is about 2300 meters and composed of heavy rainfall and snow in two limbs. Also, the isotopic composition of downstream springs is the average of the amount of isotopic value boreholes in the north and sought limbs showing that springs catchment area in left side (SPL) and right side (SP5) is recharged from both limbs of the anticline. Finally, the results of the studies show that the Jahrom-Asmari karstic aquifer on the right side of the reservoir is an aquifer with diffuse to diffuse-conduit flow. The aquifer is recharged through two anticline’s limb and mainly through the system of joints and fractures. The groundwater flows from the northern limb to the southern limb and is discharged into the springs downstream. In such a condition, the hydraulic connection between the anticline’s northern limb with the southern limb is exists. This connection is formed at the time of reservoir formation, between the reservoir and the lower springs of the dam axis with a higher gradient (around 0.037). Therefore, by the dam impoundment, the major seepage current in right abutment of the reservoir in the north limb of anticline towards sought limb and finally discharge in springs downstream of the dam axis

Water scarcity is one of the problems to the utilization of water resources in the agriculture sector. Therefore, a principled management of water resources is needed to optimally meet the water requirements of this sector. The Irrigation water allocation management could play an important role in confronting the water scarcity of the agriculture sector. Use of optimization technique to optimally allocate water and land has recently been proposed and used in many studies and it was proved to be very effective in the optimal water allocation problems. Rabie et al. (2015) allocated water to the lands irrigated by Ordibehesht canal of Doroodzan irrigation network in Fars Province using genetic algorithm. Results indicated that total cultivated area could be reduced by up to 12% under optimal water allocation situation. Results of the study conducted by Mizaei et al. (2017) on optimizing the cropping pattern of Golestan irrigation network using genetic algorithm demonstrated that 38% of the available water left as the surplus water after the optimization. This amount of water could increase the cropping area by 1388 hectares. In this study, an optimization model was created to optimally allocate the available water to Maroon irrigation network which is located in Khuzestan province of Iran using the genetic algorithms optimization method with the purpose of maximizing the total net benefit.

First, the water requirement of all crops in the Maroon irrigation network was calculated according to Allen et al. (1998) using Cropwat 8.0 software. Then, an optimization model was created to optimally allocate the irrigation water to the cropping pattern of the Maroon irrigation network using Matlab software. In this model, the water year was divided into 36 periods consisting of 10 days. The amount of irrigation water depth of the crops and their cropping area were considered as the decision making variables of the model. As Genetic algorithm has been proved to be effective in the recent optimal irrigation water allocation and cropping pattern studies, the genetic algorithm optimization method was used in the model to allocate irrigation water to the Maroon irrigation network with the goal of maximizing total net benefit (Faghihi et al., 2015; Rabie et al., 2015; Mirzaei et al., 2017). Furthermore, particle swarm optimization method was used in order to verify the results obtained by genetic algorithm optimization method. Comparison of the results obtained using the mentioned optimization methods can demonstrate whether the genetic algorithm results are verified or not. In order to achieve the optimal solution, both of the optimization methods had some parameters to be set. The parameters were set using the Vikor index according to Akbaripour and Masehian (2013).

Total net benefit maximization results obtained by particle swarm optimization method verified the maximization results of total net benefit obtained by the study model using genetic algorithm optimization method. The model Results indicated that the cropping pattern of all crops is increased except alfalfa and wheat. Total cultivated area of the network is increased by 1271 hectares which means that 14% of the abandoned area of the network could be recultivated. There are so many lands that were cultivated in the past and is not currently under cultivation because the available water resources cannot meet all of the water requirements of the agriculture sector in the study area. So, some of lands were abandoned and is not under cultivation anymore, but the optimal allocation of irrigation water is an efficient strategy to handle the water scarcity challenge in the agricultural sector and some of these lands could be cultivated again which leads to a more efficient agriculture sector. Furthermore, the irrigation depth was reduced in all of the crops, but this was compensated by the model using the available soil moisture. So, the crops were exposed to insignificant amount of water stress and the crops yield is not significantly reduced, however, the amount of total water use is not significantly reduced in comparison to the current irrigation water allocation situation because the network total cropping area is increased. The water resources allocation optimization lead to increase in total net benefit by 74.9 billion Rials. Results also proved the efficiency of genetic algorithm in this water allocation optimization model by increasing the total cropping area and the network total net benefit.

In recent years, rising water table has been reported in many cities of the world. Groundwater and engineering structures are interconnected; therefore, water table fluctuations in these areas can affect structures. Mashhad city is one of the major metropolises in Iran and due to indigenous population and tourists, it needs various resources to supply water. The city water needs are supplied from the Mashhad aquifer, Dousti dam and other catchment areas. The water table uplift in Mashhad city created a problem when commercial and residential complexes with a depth of more than 20 meters of excavation with the arrival of significant amounts of water to the lower classes were encountered. In addition, due to the lack of necessary measures due to the declining groundwater level in the past years; the encroachment on water during the drill of the second metro tunnel has caused serious problems. The lack of full development of drainage systems and municipal sewage networks have led to an increase in rising groundwater levels in some parts of the city. Also, the development of urbanization and the ever-increasing depth of excavation in urban areas may sometimes have impacts on the ground water situation. Therefore, approach of this research is to assess the major factors effecting on the groundwater uplift in Mashhad city. In order to determine the relationship of these factors with water table fluctuations, time series analysis was used in both time and frequency domains. One way is to move up. According to the groundwater hydrograph, a decreasing trend are observed during the years 2005-2009. While, from 2009 to 2014, these fluctuations followed the uptrend. Time series analysis shown, due to existence of impermeable surface in the city, low infiltration of rainfall in the soil and water table depth more than 5m, rainfall and evaporation did not have a tangible impact on the fluctuations in groundwater levels in these areas. The annual expansion of the sewage network and the transfer of wastewater collected to wastewater treatment plants with a lag tome 1 to 2 months have a significant effect on reducing the water table in areas with sewage network; While in areas without sewage network, due to the penetration of water from septic wells into ground water, it increases the level of water in these areas. The arrival of more than 800 million cubic meters of water from the Dousti dam and reduction of more than 40 percent of discharged groundwater in Mashahd aquifer with lag time 1 to 2 months, are the most influential factors in groundwater uplift. The lack of development of sewage networks in the southern regions and some parts of central Mashhad city has led to an increase in groundwater levels in these areas. Due to the extraction of soil from saturated and unsaturated zones during the drilling of the 2nd line of metro and the development of excavation and construction of civil engineering projects in the city's central area, especially around the Imam Reza's holy shrine, soil porosity has been decreased. This porosity was previously filled with water. But they are now occupied by impenetrable materials. Therefore, the water has been forced to migrate to other places. The aim of this research is to assess the major factors affecting on the groundwater uplift in Mashhad city, Iran. In order to determine the relationship of these factors with water table fluctuations, time series analysis was used in both time and frequency domains. Results show lag times between water table with rainfall/evaporation, transferred water (Dousti Dam) to the town, discharged water from aquifer, expansion of sewage network in region with network and region without network were 9, 2-3, 3-4, 1-2, 3-4, 2-3 and 3-4 months respectively. In this study a calculated drawdown by exploitation from aquifer equals 0.5 m, the calculated rising equals 0.44 m due to transferred water from Dousti Dam, the expected groundwater rising equals 2.7 m in region without sewage network and an expected drawdown equals 1 m (if no water was transferred from Dousti dam). Also, effects of excavation in line 2 of subway and urban foundation digging on the groundwater and soil properties were studied. Results show that the water storage capacity in saturated/unsaturated zones have been reduced and water table raised about 1.25 m in the town aquifer.

Dams reservoirs are among the most important sources of fresh water. In the event of a loss in the useful volume of the reservoirs, their capacity for water containment and storage decreases. The most important factor in reducing the useful volume of the reservoirs is sedimentation, and the most important factor of sediment transfer in reservoirs is density current. The density current is a stream that created by the effect of the difference in density between two fluids on the gravitational acceleration. Figure 1 demonstrates the density current movement. Fig1_Shematic of dense current (Altinakara et al. 1996)

Experiments were carried out at the Hydraulic Research Laboratory of Faculty of Water Science Engineering, Shahid Chamran University of Ahvaz, in a 780-mm-long, 70-cm-long flume with a slope of minus 1 to3.86%. The flume was divided into two sections by a sluice gate. The right side of this gate was filled with the clear water. The clear water level was maintained by the gate at the end of flume. On the left side, the solvent of water and salt is entered. This gate was able to be rapidly opened and discharge the water and salt solvent with a specific flow rate into the clear water. In the present study, four different modes of application of three successive obstacles were investigated for density current controlling. The height of the obstacles was considered by three ratios of density current body height as hr =0.5, 0.75, 1(hr = hm/h, where hm is the obstacle height and h is the average height of the body of the density current). In 3 modes of obstacles configuration, the height of the obstacles was identical and in the fourth state, three obstacles with similar dimensions were placed ascending. Experiments were performed at 3 slopes of 0, 1.5 and 2.5%, with two concentrations of 10 and 20 gr /lit and a constant flow rate of 1 L/s.

The results showed that the density flow frontal at all slopes and both concentrations of 10 and 20 gr/lit, had almost the same velocity before reaching to the obstacles. As the forehead encounters the first obstacle, the speed of the forehead decreases significantly and continues to decrease until the last obstacle. The highest percentage of frontal discharge control at two concentrations of 10 and 20 gr/lit was for h_r(1) S_0 and was calculated to be 84 and 87 percent, respectively, and the lowest percentage of frontal discharge control at same concentrations was for h_r(0.5) S_2.5, and calculated to be 25 and 31 percent , respectively. For the ascending configuration of obstacles, the density current frontal discharge control percentage at the slopes of 0, 1.5 and 2.5% for the concentration of 10 gr/lit is 74, 52, 44 and for the 20 gr/ lit was measured to be 78, 58 and 48 percent.

Today, the construction of dams is one of the most important solutions for the storage of surface water. Due to fresh water limitations, the construction of reservoir dams to control the surface water resources in Iran is inevitable and necessary. In dam reservoirs, the turbidity current is usually the cause of sediment transfer and deposition. If the current is completely stopped in the middle areas of the reservoir, the amount of sedimentation will be reduced at the bottom of the dam wall and, as a result, the main functions of the dam will not be disturbed. Therefore, it is necessary to study this phenomenon. One of the methods for hydraulically changing the turbidity current is to roughen it or to use a barrier in the bed. Several studies have been carried out on the velocity of the turbidity current so far, and controlling it by roughening and barriers. However, it seems that no studies have been made on the effects of the angle and location of impermeable submerged plates on the turbidity currents.

Here, 42 experiments were made on the effects of the impermeable submerged plates on the head velocity and the height of the turbidity current head. For this purpose an experimental, flume with 30cm width, 10m length and 46cm height was used. The turbidity current entered the flume with concentrations of 20 and 40 g/l and bed slopes of 1 and 2%. In order to investigate the effects of the angle of the impermeable submerged plates, impermeable plates which came into seven different angle of mounting of the plates with respect to the current axis (0, 15, 30, 45, 60, 75, 90 degrees) and also, impermeable plates with eight locations were located across the current. Measurements of velocity and height of the head turbidity current were made on 6 sections with 50cm distances. Then, based on the data obtained, and by dimensional analysis of Edgar Buckingham’s method (Buckingham π methodology), the non-dimensional graphs of velocity, height and Densimetric Froude Number of the head of turbidity current were plotted.

According to the performed experiments, the results of this study are presented in two sections. In the first section, the results are related to the effect of the plate angles; in the second, the results are related to the effect of the plate positioning. Generally, due to the collision of the turbidity current with the plates, the non-dimensional velocity was reduced along the mounting route. Also, the Densimetric Froude Number was decreasing along the current route. The results showed that with increasing the angle of the plates, the decreasing gradient of the dimensionless velocity increases along the dimensionless route. Therefore, the plates with angles of 75° and 90° which are in the vertical and near-vertical position relative to the current axis, are affecting the current flow velocity more than plates at other angles. In general, the flow velocity of the turbidity current decreased by 8.6 to 27.1% with respect to the control state in case of different angle of mounting of the plates with respect to the current axis. With a concentration of 20 g/l and the slope of 1%, the plates with the mounting angles of 75 and 90° relative to the horizontal axis of the turbidity current flow provide the most significant decrease in the velocity compared to the control, with 26.4% and 27.1%. The analysis of the position of the plates showed when the plates are mounted across the total width of the canal, they provide the most significant reduction in the velocity compared to the control. In general, in different conditions, the flow velocity of turbidity current increases to 6.3% in the worst location and decreases 45.1 percent in the best location relative to the control state (in bed without submerged impermeable plates). With a concentration of 20 g/l, the plates at the position of 2, with 45.1% and the slope of 1%, and 29.5% at the slope of 2%, made the biggest decrease in the current head velocity compared to the control. Also, with the concentration of 20g/l at the slopes of 1 and 2%, the position 5 made the biggest decrease in the velocity with 33.9 and 38.3%. Slope investigations showed that with the concentration of 20 and 40 g/l, the slope increase will reduce the effect of the plates on the velocity.

Abstract

The melted ices, reduced snow covers, increased air temperature, change in frequency and duration of droughts and change in precipitation patterns are evidences of the climate change (Ehsani et al., 2017; Huber and Knutti, 2011; IPCC, 2014). Different alternatives of driven factors (population and economic growth, technology efficiency and type of used energy) are considered in the 21st century to project the greenhouse gasses in the Representative Concentration Pathways (RCPs). These assumptions lead to the three RCPs, including a stringent mitigation scenario of RCP2.6, an intermediate scenario of RCP4.5 and, a very high greenhouse gasses emission scenario of RCP8.5 whose radiative forcing is +2.6, +4.5, +6 and +8.5 W/m2, respectively in the year 2100 relative to pre-industrial values. The global warming is +1, +1.8, +2.2 and +3.7 ℃, respectively at the end of the 21st century (2081-2100) relative to 1986-2005 (IPCC, 2014). The study of the temporal variability of the observed precipitation and temperature in southern Iran showed that the precipitation and temperature trends are negative and positive, respectively (Tabari and Talaee 2011a, 2011b; Kousari and Asadi Zarch 2011; Tabari et al. 2011; Kousari et al. 2011). There are large dams such as Dorudzan and Molasadra and natural lakes of kaftar, Arzhan and Parishan over the study area which may adversely affected due to climate change in future. Therefore, the objective of this study is to find how the climate variables of precipitation and temperature, drought duration and intensity of extreme storms will change under climate change.

The six climatic stations are selected based on the longest common daily records of precipitation and temperature data (1978-2005) to investigate the climate change in the study area. In this study, the daily outputs of the 22 CMIP5 models are applied for climate change study. The LARS-WG is used to downscale each GCM-predicted data in 6 stations. The observed daily data during the 28-year period of 1978-2005 are inputted to the LARS-WG to calibrate it for each station. Then, to verify the LARS-WG at each station, the 28-year daily precipitation, minimum and maximum temperature are generated and statistical characteristics of the generated data (statistical distributions and mean values) are compared with observed ones at significance level of 0.01 using Kolmogorov–Smirnov (K-S) and Student’s t-test (Semenov and Barrow, 2002). The verification results imply that the LARS-WG reproduces the daily data well in 6 stations. The change factors are calculated using the given GCM data and relevant grid box to downscale that GCM output for each climatic station. the change factors are calculated using a transient approach in which 5-year future time windows shifted forward by 1-year.

The downscaling results in Abadeh station indicate that the mean annual temperature will increase from 14.3 ℃ during the period 1978-2005 to 16.1, 16.7 and 17.7 ℃ under the RCP2.6, RCP4.5 and RCP8.5, respectively, leading to the warming by +1.8, +2.4 and +3.4 ℃, respectively. The downscaling results show that the mean annual precipitation will decrease from 452 mm during the observation period (1978-2005) to 386, 353 and 357 mm under the RCP2.6, RCP4.5 and RCP8.5, respectively, leading to precipitation reduction by 14.6%, 22% and 21%, respectively. The intensity of extreme storms with different return period are estimated using the maximum annual series during the observation period and three RCPs. The goodness of fit on statistical distributions of Exponential (1P and 2P), Gamma (2P and 3P), General Gamma (3P and 4P), Log-Gamma (2P), General Extreme Value, Normal, Log-Normal (2P and 3P), Pearson (2P and 3P) and Log-Pearson (3) shows that the General Extreme Value is the best-fitted statistical distribution on maximum annual series. Then, the intensity of 2, 5, 10 and 20-year return period storms are determined using the fitted statistical distribution. The results indicate that the 2-year return period storms will be intensified, the 5-year storms will not be changed, but the intensity of the 10-year and 20-year storms will decrease in future due to climate change. The 12-month SPI analysis indicates that the wet and normal periods will slightly increase while droughts will decrease in the period 2040s under the three RCPs. The SPI analysis in the second period (2070s) show that the wet periods will not change, the normal periods slightly increase, but drought conditions may be intensified especially in RCP2.6 and RCP8.5.

In water scarcity conditionals, water resources management and accurate use of available water for sustainable production of required products in arid and semi-arid areas are essential. To achieve this management, the evapotranspiration plays a very important role that is one of the main components of the hydrological cycle and successes of water projects and sustainable production depends on the correct estimation of that. Determination of the water requirement of crops and gardens will increase the irrigation efficiency and improve water management in the field. In order to estimate the evapotranspiration, it is necessary to accurately calculate reference evapotranspiration. So far, many experimental methods have been proposed to estimate the reference evapotranspiration. The penman montieth fao method is one of the most precise methods to determine of that and limitations of using that is calibrating for areas that will be used.Over the last few years, the uses of learning tools and innovative methods have been widely used to estimate the reference evapotranspiration. Therefore, it is necessary to check the correctness of these models and methods for different regions.

Sistan is one of the fertile regions of Iran, which, unfortunately, over the years, the phenomenon of drought has been swept away the active farming in the area and destroyed a boom in agricultural production in this region. Nevertheless, the main occupation of rural people in this region is still agriculture. Any neglect on the water category in this area, can be a serious damage to it. Winds for more than 120 days are main climate feature of this region that has extremely been increase the evaporation. Therefore, it is necessary to extract the highest efficiency from the limited water in the area. So, in this research, the effective climatic parameters to calculate of daily reference evapotranspiration in Sistan plain were identified and analyzed using different scenarios of the combination of meteorological parameters. These scenarios were used as inputs models of decision trees, random forest and deep learning. The best scenario was extracted by results of models. Then, the accuracy of the results was compared with the experimental method of penman montieth fao as the basis method. Scenarios were M1 - M25. Used data in these scenarios were max, min and average of two temperature and humidity parameters, rainfall, sunshine, wind speed and pan evaporation. The data were provided from the Zabul meteorological stations for 2009-2018. 80% of the data have been use for training and the remaining 20% for testing the models.

Results of these models were compared with the estimated results by the penman montieth fao model and shown, in decision tree model, M10 scenario with the lowest error rate ( RMSE=1.003 ) and the highest correlation coefficient ( R=0.983 ) was the best scenario. In random forest model, M10 scenario with the lowest error rate ( RMSE=1.003 ), MAE=0.8 and the highest correlation coefficient ( R=0.983 ) was the best scenario. In deep learning model, M5 scenario with the lowest error rate ( RMSE=0.517 ), MAE=0.399 and the highest correlation coefficient ( R=0.996 ) was the best scenario. In results of the supporting machine model and selecting the best model, by evaluating the comparison of decision tree and deep learning models, it was shown that a specific pattern can be introduced for Sistan region with proper accuracy for estimating daily reference evapotranspiration and should introduce a superior scenario for each model. In order to deliberation the importance of various meteorological parameters in the results of the mention models, among all the parameters have used in decision tree model, average temperature, wind speed, maximum temperature and minimum temperature, respectively, had the most importance. In random forest model, maximum temperature, wind speed, average temperature and pan evaporation, respectively, had the most importance. Finally in deep learning model, average temperature, maximum temperature, wind speed and minimum humidity, respectively, had the most effect on calculation of daily reference evapotranspiration in case study region. As a general conclusion can say, deep learning model is the best model among selected models and M5 scenario in deep learning with the highest correlation coefficient ( R = 0.996 ) and the lowest error ( RMSE=0.517 ), had a good accuracy to modeling of daily reference evapotranspiration.

The use of models in snowy basins, due to the effect of snow’s properties, requires quantitative and qualitative knowledge of the factors on the melting and runoff resulting from it. Temperature is one of the factors. The impact of its variation on the performance of model based on the degree-day approach should be explained. For this purpose, in the Samsami catchment, the Longitude of 50, 10, 2.2 seconds to 50, 26, 17.6 seconds East and Latitude 32, 5, 16.5 seconds to 32, 15, 1 seconds North the area of 266 square kilometers evaluated the performance of the SRM model in different melting season in years 1393 to 1394 using a product of maximum eight-day snow cover (MOD10A2) and criteria for assessing EI efficiency and Volume Ratio. Then it was processed using ENVI software and ArcGIS software was provided with digital model, composition and snow cover curves. Determination of snow melting season was carried out using snow cover curves. To determine the beginning of the melting season, changes in snow cover levels between 2008 and 2016 were investigated in the Doab Samsami’ basin. This basin is one of the northern Karun sub basins in Chahar Mahal and Bakhtiari province with an average rainfall of 1,175 millimeters per year. 61 percent of the precipitation is snow and 39 percent is rain. Due to the significant drop of snow at the surface of the basin, there are large permanent and seasonal springs. The most important of these are the Dezdaran and Koufi springs. These springs have a relatively large reservoir and the origin of the formation of two rivers are named for these two. The two rivers joined in the geographical position of 50 degrees, 17 minutes and 15 seconds east longitude and 32 degrees, 10 minutes and 14.1 second northern latitudes in the vicinity of Samsami village at altitudes of altitude of 1993 meters from the sea level, the water of two waters of Samsami is formed. The study basin has the Doab Samsami meteorological station and Safa Abad hydrometric station at the outlet point of the basin. The basin lacked a snowstorm station, which is why the synoptic Kouhrang station, the nearest Synoptic station to the Doab Samsami basin, was assisted. The use and interpretation of model simulation results is subject to the study of temperature’s variations in different altitudes. The performance of the model in different months of melting is different due to the variable state of the structure of snow accumulated due to temperature. The temperature difference in the melting months, with the effect of stacking on the snowpack, causes the snow to ripe. On the other hand, the ripening of snow causes delays in runoff due to melting and, as a result, the difference between observational and simulated discharge. Because the ripening phenomenon is directly related to the temperature, it can be said that the performance of the RMS model decreases with increasing temperature, in proportion to the melting season. Accuracy of model SRM decrease with increasing temperature. For February to May, the Volume Ratio rises from 10 to 40 percent for an increase of 16 ° C. The observed difference between simulated and observational values in May, the end of the melting season, was such that the value of the volume difference increased to 40% and reduced the efficiency by minus 0.55. These results were obtained in March, the second month of melting, with a mean temperature of 4 ° C, the volume difference decreased by 3.5% and the efficiency index increased to 0.81. Hence, due to the very good results of the SRM model in March, its simulation results can be used with acceptable capability to estimate snow flood from the studied basin. However, the use of the model in months with a mean high temperature and the end of the melting season, due to snow structure transformation, has a significant error in the simulation results. In order to estimate the snowflake outflow, more attention should be paid to the role of the springs and the necessary modifications are made in simulation results. Statistical simulations include Volumetric Difference (%) and Efficiency Index (Dimensionless) in each months of February, March, April, May are 17.1, 3.5, 14, 40 and 0.83, 0.81, 0.66, -0.55 respectively. It is therefore seen that, gradually, with the melting months, the accuracy of model estimation decreases. So, the use of model outcomes in the end months of melting requires temperature correction. In March, the best fit and in May, the lowest compliance is observed.

Water shortage in the Iranian plateau has always been the main concern, and one of the most important achievements of people in this region is to devise methods of irrigation and water management. Following the selection of the city of Isfahan as the capital of the Safavid Empire, size of the city expanded, and its population continued to increase. These two factors created the need for a systematic structural design for water management. This research has tried to look at the water management system in the Isfahan in Safavid era, by researching the historical documents. This study is a historical research, and is conducted with an analytic approach, based on a documentary and library study. Shah Abbas I and his designers succeeded to organize the city water supply system in response to the significant increase of population of the city. In the first step of the decision to increase the volume of water from the originate which is taking place in different periods. But due to various technical, climatic, and instrument flaws, this project wasn’t successful in Safavid period. After the failure of this project, in the second step, decision for a better target management of this volume of water access was taken. Water volume and time management was planned based on Sheikh-Bahai scroll. This document is now the most important historical source in this regard. The most important Safavid achievements in the field of management practices is designing a developing city based on access to water resources. the expansion of the Safavid city generally occurs to the west and south, i.e. in the direction of the river entry and its splits into the city fabric. Accordingly, the loss of water due to its leakage and evaporation decreases during the water supply route in rivers along the way. In the region of Isfahan, when moving from the west to the east near to the central desert, the climate, evaporation, and type of soil changes. During this period, the urban needs of water was provided from underground resources; We read in all travelogues and historical sources of this period that there were several factors behind this choice: water wells, Qanats, and springs were lighter and softer than river water. The high level of underground water in the region of Safavid Isfahan made these resources in every part of the residential area accessible. Water for irrigation of gardens and fields was provided from branches of the Zayandehrood River called Maadi. Many of these splits were created before Safavid with the aim of irrigating gardens and farms. In the Safavid period, changes in these structures occur. Firstly, in addition to irrigating farms and gardens of outskirts, the urban structures and the architecture made for water supply also improves. Secondly, new splits were defined in order to supply the water of emerging parts in the developing process of the city. Niasarm watercourse that before Safavid irrigated only the farms, in Safavid period, due to the changes in the fabric of the northern shore of the river, firstly irrigated the gardens near to Alah-Verdi-Khan and Khaju bridges and then the residential quarters of this area. Farshadi watercourse also plays a similar role in his way to the east by crossing the Safavid structures such as Madar-Shah school and caravanserai. However, the most important watercourses for this research are Shah-Kabir or Jouishah and some ways are advised and the share of each space from the watercourse is identified. According to the Sheikh-Bahai scroll, the Fadan watercourse is the most effective water supply in the urban fabric, the ancient part particularly; and mentioning its share, a section titled "urbanization" is clearly identified. Following some of the shares named in the scroll, the water supply of this watercourse to the northern and the eastern fabric of the city are shown. In the heyday of the Safavid, management of water resources was very efficient and accurate. At the end of the Safavid period, the government fell, corruption and bribery were common, and simultaneously, the water management system became very shaky. Increasing pressure on farmers shook the foundations of the economy, and accelerated the fall of the government. On the other hand, the discontent of farmers, lead to the decline of government.

Increasing population growth necessitates more food production, which requires more activities in the agricultural and industrial sectors, which has necessitated the presentation of effective strategies for water resources management. One of the strategies that has been considered in water resources management in recent years, especially in the agricultural sector, is the measurement or estimation of evapotranspiration that The monitoring and evaluation of changes in certain periods of time can be important in determining the amount of water consumed by the plant and planning irrigation, and thus determining the irrigation systems capacity. Also, Conventional ET measurements using lysimeters, the Bowen ratio, and eddy covariance systems (EC) are mainly based on site (field)-measurements. Although they can directly or indirectly measure turbulence fluxes (latent and sensible heat flux; LE and H), conventional techniques likely entail substantial observation errors during bad weather and other conditions. These methods, therefore, cannot represent large-scale terrestrial ET. Since direct and indirect methods of calculating this parameter have limitations; recently, remote sensing methods for calculating evapotranspiration are used. However, remote sensing data combined with some meteorological data provide a means to estimate regional ET, given the advances in remote sensing technology. Some land surface variables related to ET, such as surface albedo, surface emissivity, and land surface temperature, can be estimated directly by remote sensing data. Actual ET can be estimated by a set of equations hierarchically, which converts spectral radiances derived from satellites or airplanes images into actual ET. One of the models based on remotely sensed data is the Surface Energy Balance Algorithm for Land (SEBAL) model, in which the land surface temperature, albedo, emissivity, and normalized difference vegetation index (NDVI) are of significance to estimating regional ET. In the present study, Lenjan County in Isfahan province, which was under rice cultivation, was selected and Surface Energy Balance Algorithm for Land (SEBAL) was implemented on 8 satellite images of Landsat 8 from June to September 2017 (growing season). For this purpose, the main components of the energy balance equation, including net radiation flux, soil heat flux and sensible heat flux to the air for each image, have been calculated and the instantaneous evapotranspiration flux for each pixel is estimated as the residual energy balance equation. To improve the non-dependency on ground data, a general equation was therefore used. The Net Radiation is the electromagnetic balance of all incoming and outgoing fluxes reaching and leaving a flat surface. The amount of shortwave radiation (RS↓) that remains available at the surface is a function of the surface albedo (α). Surface albedo is a reflection coefficient defined as the ratio of the reflected radiant flux to the incident radiant flux over the solar spectrum. It was calculated using satellite image information on spectral radiance for each satellite and the incoming shortwave radiation (RS↓) was computed using the solar constant, the solar incidence angle, a relative earth-sun distance, and a computed atmospheric transmissivity. The incoming longwave radiation (RL↓) was computed using a modified Stefan-Boltzmann equation with atmospheric transmissivity and a selected surface reference temperature. Outgoing longwave radiation (RL↑) was computed using the Stefan-Boltzmann equation with a calculated surface emissivity and surface temperature. Surface temperatures were computed from satellite image information on thermal radiance. The surface emissivity is the ratio of the actual radiation emitted by a surface to that emitted by a black body at the same surface temperature. Soil heat flux was empirically calculated using vegetation indices, surface temperature, and surface albedo. Sensible heat flux wass computed using wind speed observations, estimated surface roughness, and surface to air temperature differences. Sensible heat flux is the part of internal energy of a substance that is proportional to the substance’s temperature. Also, empirical methods of evapotranspiration including Blaney- Criddle, Hargraves- Samani, FAO- Pennman- Monteith and Kimberly- Pennman were also evaluated in the study area. Accordingly, the SEBAL model in the study area has the maximum and minimum daily evapotranspiration in the pictures of June 25 and September 11, equal to 7.95 and 5.88 mm/day. Among the various parameters affecting the SEBAL algorithm, the net radiation flux parameter with consideration of other parameters such as vegetation indices, surface albedo, and incoming and outgoing of radiation, had the most effect on the results of SEBAL algorithm. Among different empirical methods, Hargraves- Samani and Blaney- Ciddle had less percent error which has a suitable correlation with SEBAL results. SEBAL algorithm has been able to estimate the temporal and spatial variation of evapotranspiration in the study area with an acceptable accuracy. Alternatively, this algorithm can be used to replace time-consuming and costly methods of calculating evapotranspiration at different surfaces.

The atmospheric conditions and rainfall shortage have increased the utilization of groundwater resources in the northern regions of the country. Therefore, the evaluation of groundwater resources in the aquifer of the Nekarood plain is of great importance due to the high use of groundwater resources and subsequent use of chemical agents such as fertilizers and pesticides in agricultural lands. The purpose of this study is assessing the vulnerability of aquifer Nekarood area in Mazandaran province with the DRASTIC model.

In this study the potential of groundwater contamination was evaluated with the DRASTIC model. This model evaluates the groundwater potential with seven different parameters (Depth, Net nutrition, Aquifer media, Soil media, Topography, Non-saturated media, Hydraulic conductivity). In this study, the weights of each of these parameters were first determined using the layer overlay method in GIS for each of the seven parameters and the desired range. Then, the columns of each of the ranges in the GIS were converted to the Raster layer and using the Raster calculator, the total number of layers with the obtained weight was summed up and the risk maps were finalized in the region according to the model of the DRASTIC model. To illustrate the variation of water quality elements using the Kriging statistical method, to determine the correlation and verbose of the results of the DRASTIC model, the SPSS 22 software was used to determine the final stroke index with nitrate, pH and EC parameters.

The results of the evaluation with the DRASTIC model in the area of Nekarood showed that the area with a high vulnerability only 17.33% of the total area of the region and region with low vulnerability potential includes52.97%. Pearson statistical test was used to show the relationship between the results of the DRASTIC model and the values of nitrate, pH and EC. The results of the test showed that the relationship between the DRASTIC model with the values of nitrate, PH and EC is 0.610, 0.254 and 0.277, respectively. The Nekarood plain is one of the major contaminated areas due to the use of pesticides and chemical fertilizers with the aim of increasing the yield of agricultural products. According to the results of the model, the southeastern range of the region has a high vulnerability due to the different texture and physical conditions of the soil, and the north-east to a part of the center of the plain has a low vulnerability. Downstream areas have a more coarse texture than the southeastern part, and this is due to the movement of materials to the sea level so there is less pollution. By verifying the model of the DRASTIC and determining the coefficient of correlation between the values of the model, it was determined that the model is in line with the qualitative elements and a scientific strategy for studying and determining the sensitivity of the aquifer in the region.

Because of evaluating and measurement of different irrigation management and identifying soil salinity consumes more time with high cost, so applying models can overcome these problems and could be used in different irrigation scenarios. Variation Crop models are an appropriate tool for investigating irrigation management and their effect on plant production. The purpose of this study was to evaluate the efficiency of two models including AquaCrop and Saltmed for simulation of yield and soil salinity variation. The accuracy of the results of the simulation models depends on the accuracy of the required data of the model and if the measurement and determination of the input data is accurate, then the applicability model will be in different conditions after calibration and validation. For applying Aquacrop and Saltmed models, having crop growth stages, root effective depth, sowing and havest date, harvest index, crop coefficients in different growth stages, duration of wheat phonological growth stages, initial soil salinity in different layers and some irrigation data including depth and time of water application are necessary. In this regard, the two models including AquaCrop and Saltmed are among the functional models that have high ability and efficiency to simulate plant yield and soil salinity performance have been investigated.

This research was conducted in the Ramseh region of Hamidieh, Khuzestan, in latitude and longitude 47 degrees 41 minutes and 33 degrees and 4 minutes, respectively. In this regard, three pilots of 10 hectares were selected and in each of these parts three pilot trials with an area of 2000 square meters were considered for evaluation and measurement. In the first year, using traditional irrigation management of farmers and using the initial salinity levels, soil physical and chemical characteristics compared to the simulation using two models including Aquacrop and Saltmed model. Saltmed and Aquacrop Models can simulate crop yield, Biomass and soil moisture variation in saline and non saline condition. In this investigation Aquacrop version No. 4(2012) and Saltmed No. 3-04-02(2015) has been used for crop production and soil salinity simulation. During irrigation season reference evapotranspiration has been determined using climatic data of Ahvaz Synoptic station. Data gathering including minimum and maximum temperature, minimum and maximum relative humidity, precipitation, sunshine hours and wind speed. Also, during the growing season, the volume of irrigation water, irrigation hours, water use efficiency and root depth were determined. At the end of the growing season, direct measurement of selected farms in three replications was carried out to determine the wheat grain yield and biomass along with soil moisture changes in soil profile. According to the measured data, two models of Saltmed and Aquacrop were calibrated for the first year of cultivation. Results of calibration of the first year were evaluated for verifying the results of the two models in the second year. The standard error (SE), Root mean square error (RMSE), Normalized root mean square error (NRMSE), correlation coefficient (R2), mean bias error (MBE), and model efficiency (EF) were used to determine the accuracy of the models.

The results of the first year showed that the normalized error of root mean square index for grain yield and biomass values in the AquaCrop model were 4 and 5%, respectively, and these values for the Saltmed model, were 8 and 9%, respectively. This statistical index for simulation of soil salinity with Saltmed model was about 18% and in AquaCrop model was 53%. Therefore, the Saltmed model is more consistent with the measured data of soil salinity. Also, the results of the second year that were used for validation showed that, the normalized error of root mean square index for yield and biomass in the AquaCrop model was 4% and 4% respectively, and these corresponding values for Saltmed model were 22 and 14% respectively. Also, simulated of soil salinity results in the second year with Saltmed model showed that this model with normalized error of mean square error(26%) was more accurate for soil salinity simulation than AquaCrop model with normalized error of mean square error equal to 47%; therefore, the AquaCrop model has a better performance than Saltmed model for yield simulation. Also the performance of Saltmed model has high efficiency and accuracy in simulating soil salinity than AquaCrop model.So based on the goal of projects and precision of simulation data, these individual models can be applied.

Since long ago, the flood control and artificial feeding of the groundwater aquifers have been amongst the most important goals in the implementation of the flood distribution systems in arid and semiarid regions. On the other hand, determining proper places for running flood distribution systems based on the various scales and indices is of great importance.

In the present study, quaternary units, slope percentage, alluvia thickness, lands’ competence, and lands’ use cases have been calculated as the influential factors and primary scales in locating the regions suitable for flood distribution and artificial feeding on southern plains of Ilam Province and the weight of each of them has been computed using Multiclass Map Model. Then, these layers were categorized in the GIS environment and their priorities were determined in terms of the effect of each factor on the specification of the regions suitable for flood distribution.

The results obtained from the prioritization indicated that the slope percentage, with a weight equal to 52.5, is the most important scale in locating the regions suitable for flood distribution in the study area. Moreover, the results obtained from the combining and weight assignment of the maps showed that 4.5% of the study area is in the very appropriate class, 10.3% is in the appropriate class, 19.3% is in the somewhat appropriate class and 65.9% is in the inappropriate class in terms of flood distribution.