مجله پژوهش آب ایران
پیاپی 41 (تابستان 1400)

One of the most important subjects in reducing the destructive energy of the flow is hydraulic jump. Hydraulic jump control is carried out to reduce the damage to downstream structures. A hydraulic jump is one of the most rapidly varied flows occurring when the flow is altered from supercritical state to subcritical. Most researchers have been tried to provide conditions for more energy dissipation by changing the design of stilling basin. In recent years, it has been determined that divergence, the presence of roughness or the formation of slopes in the basement of the stilling basin, could be effective in reducing jump dimensions and be economically feasible. An appropriate method for controlling the hydraulic jump is to use the bed roughness. In addition to reducing the length and depth and increasing the hydraulic jump energy loss, roughness stabilizes the jump in the position of the stilling basin. Besides, when the required depth for a classic hydraulic jump cannot be provided, or the cost of excavation to lower the bed of the stilling basin is not economical, construction of an expansion in the channel is a way to ensure the formation of the hydraulic jump in the stilling basin. Ead and Rajaratnam (2002) showed that the axial velocity profiles at different sections in the hydraulic jump were similar with some differences from the profile of the simple plane wall jet. Abbaspour, et al. (2009) also indicated that the longitudinal velocity profiles at different sections are similar, but they are a little different from the profiles of classic hydraulic jumps. The results showed that the dimensionless thickness of the boundary layer ( ) for jumps on corrugated beds was about 0.57, while was 0.16 for classic jumps on a smooth bed. The shear force coefficient ) for jumps on corrugated beds is approximately 10 times that for jumps on smooth beds, and the shear force coefficient showed a sharp growth with increasing Froude number.The experiments were conducted in a flume with Plexiglas bed and walls, which was 8.0 m in length, 0.40 m in width, and 0.60 m in depth. It was connected to a hydraulic circuit allowing for recirculation of discharge. The discharge in the flume was obtained from an overhead tank. The discharge was measured by a calibrated magnetic flow meter located in the supply line, with ±5% accuracy. Water entered the flume under a vertical sluice gate, 1.2 m deep. The supercritical depth was controlled by the upstream sluice gate, while the tailwater depth was controlled by the downstream sluice gate. The point gauge with an accuracy of 1 mm was used for the measurement of the depth of water at various locations in the flume. In each experiment, the flow velocity was measured by using a pitot tube in several sections of the jump length. Twenty-five piezometers were installed on a false floor, at the site of the hydraulic jump. Phenomenon during the jump was investigated by these piezometers. The divergence ratio was considered in the range of , and natural rough bed conditions with 0 ≤ ks/d1 ≤ 0.9. In total, 81 experiments was conducted in the range of Froud numbers of 4.9 to 9.5 and discharge of 30 to 50 . For the rough bed, the reference level was assumed coincident with the plane passing at the top of the particles that the height was assumed equal to the median size (d50).Primary and sequent depths were measured by point gauge and velocity profiles by pitot tube.By investigating the velocity profiles, it was found that the relative thickness of the boundary layer  was 0.51, while for the classical jump was 0.16.When both roughness and abrupt expansion parameters were used, the value of shear force coefficient (at expansion ratio of 2 and roughness size of 2.2 cm) was 14.7 times the shear force factor in classical jump on average. The water fluctuations, pressure variations the probability of existence cavitation were studied using the piezometers installed at the bottom of the stilling basin. As the expansion ratio and the roughness size increased, the cavitation coefficient decreased. The measurements showed that there was no cavitation in these experiments. In the most critical case, the cavitation coefficient in the structure did not fall below 5.7.

Access to adequate water and sanitation is one of the basic needs of the rural community. Most of the energy needed to supply, transportation and distribution of rural drinking water is provided by pumping stations. Considering the importance of saving energy, investigation on the efficiency of pumping systems of rural water supply facilities is very important. The efficiency of pumping systems is related to several factors such as: hydraulic, electrical, mechanical, maintenance and management factors. Therefore, it is necessary to evaluate the performance of pumping stations in accordance with the effective factors. Perju and Aldea (2018) studied the upgrade of the pumping stations for an urban water network, to reduce operating, maintenance and water loss costs in distribution networks. The results showed technical solutions within the structural and functional modifications of the pumping stations can lead to both the improvement of hydraulic parameters of the pumping stations and significant energy savings.  This research was conducted to investigate the efficiency of pumping stations of water supply facilities in villages of Ilam province. This province with an area of 20 thousand square kilometers and a population of about 580 thousand people is located in western of Iran. Ilam has a semi-arid climate with an average annual temperature of 21 degrees Celsius and an average rainfall of 480 millimeters. About 30% of the province's population lives in villages with a household size of 3.7. About 99.4% of the rural population of the province is connected to the rural water networks. Pumping stations supplied 81.6% of the total capacity of drinking water. In this province, the consumption of rural water per capita and the water production per capita are 143 and 215 liters per day, respectively. Therefore, water loss is 33.5%. Energy efficiency in pumping stations depends on several factors. For this reason, the evaluation of pumping stations should be systematically reviewed. In general, hydraulic, electrical, mechanical, operation, maintenance, environmental and management conditions affect the operation of pumping stations. Optimal selection of any of the above can be effective in achieving optimal station efficiency. To perform this research the following variables were determined: hydraulic variables (flow velocity, flow rate and pressure), electrical variables (current, voltage, power factor and consumption power), mechanical characteristics (type of pump and electromotor), and geometric characteristics (well depth and pipe diameter). Then, by calculating the power output and consumption power of the electro pumps, the efficiency of each separate station was determined. Using the weighted average method, the average efficiency of the floating electro pumps installed in the water supply system was obtained. The efficiency (η) of each pump can be calculated by the ratio of consumed power (Pc) to the produced power (Pp). Produced power is a function of density (ρ), gravity (g), discharge of pump (Q), and pumping height (H). While, the consumed power (Pc) is related to   voltage (V), electric current intensity (I) and a power coefficient (CosØ) The results of this research indicate that the average efficiency of pumping stations in rural water supply facilities in Ilam province is 61.4%. Among all the selected stations, about 75% of the stations are running with the efficiency of 65.9%. Studies show that the reasons for high efficiency of some pumping stations are the low operating hours of electric pumps, the significant population covered by them and the related social issues. Moreover, about 25% of the flow pumping has the average efficiency of 47.7%. This value of efficiency is relatively low that is mainly related to the pumping stations with low flows. The efficiency of pumping stations is affected by several other factors. Among these factors, the methods of operation, maintenance and management can be mentioned. Installing valves and appropriate equipment on the drift line, Proper placement of transmission lines, avoid making sharp bends and a review of the design of water supply networks, in general, can save a significant amount of energy. Installation of remote control systems, pressure transducers, ultrasonic flowmeters and devices for measuring electrical parameters can make it easier to monitor the operation of the pump station at the optimal point. Consequently in order to increase energy efficiency, it is necessary to review the design of pumping stations, installing performance monitoring equipment at pumping stations, timely repair, regular operation and maintenance, and operators training.

Bridges are of the most important structures in rivers that are widely used for various purposes. The occurrence of scouring around the pier and abutment is one of the main factors in the destruction and failure of them. Statistics show that scouring around the abutment causes more problems compared with the pier scouring. Out of 108 bridge failures that occurred during 1960–1984 in New Zealand, 29 cases were related to bridge abutment scour. Respect to the importance of the issue, the research community has always sought to find scientific solutions to minimize the significant effects of scour around the bridge abutments. Two different methods are used for controlling and reducing erosion in river bed: increasing the bed resistance and changing the flow pattern. In the method of changing the flow pattern, different structures such as spur dike, slot and collar are used. In the method of increasing the strength of bed particles, protective tools such as concrete block and riprap are used. Spur dikes are among the structures that can reduce the scouring at the abutment by diverting the flow from the abutment and directing it towards the river axis. Although T-shaped spur dikes are of the most important forms of spur dikes, so far no comprehensive research has been done on the effect of this type of spur dikes on the reducing scouring around it. Many limited studies that have been done so far are related to rectangular channels. Therefore, their results cannot be used for supports abutment that are located in the compound channel. In the present study, by constructing a laboratory model, the effect of placing a T-shaped spur dike on reducing scour around the bridge abutment was investigated. The experiments were performed in a flume with the length of 12, width of 1 and height of 0.6 m. The length of the compound section was 6 m, which was installed at the distance of 3 to 9 m from the beginning of the channel. The main channel was made of glass and had the width of 20 and a depth of 8 cm. Both sides of the main channel were filled with a thickness of 30 cm of uniform non-cohesive natural sediments with an average diameter of d50= 1 mm. The abutments used were made of galvanized sheet with the length of 15 cm and the semicircular nose with a diameter of 10 cm. The T-shaped spur dikes with five different lengths of webs and wings were installed at three distances of 0.8 L, 1.2 L, and 1.6 L (L: support length) from the abutment. Then the effect of these variables on the reducing of scour around the abutment evaluated. The experiments repeated in three different ratios of average flow velocity to critical velocity of 0.7, 0.8 and 0.9. Results showed that the T-shaped spur dike could reduce the scour around the abutment by the average 75%. In the best case in terms of dimensions and distance, this type of spur dike would reduce the scouring around the abutment by 91%. Increasing the web length enhanced the efficiency of the spur dike. By increasing the dimensionless length of the spur dike by 100%, the spur dike efficiency enhanced by 37%. Increasing the wing length also increased the spur dike efficiency, So that with a 100% raise in the dimensionless length of the spur dike wing, the spur dike efficiency improved by 17%. At a constant length of web and wing, with increasing distance of the spur dike from the abutment, the effect of the spur dike on the abutment scour decreased and the scour depth at the abutment increased. By increasing the distance of the spur dike from the abutment by 100%, the efficiency of the spur dike was decreased by 10%. The results showed that the length of the spur dike had a greater effect on the efficiency of the spur dike compared with the length of the wing and the distance of the spur dike. The average efficiency of the spur dike in critical velocity flow ratios of 0.7, 0.8 and 0.9 was equal to 78, 75 and 70%, respectively; this showed that with increasing the ratio of flow velocity to critical velocity, the efficiency of the spur dike had not changed significantly. In other words, this type of spur dike maintained its efficiency in different flow conditions.

Cotton or white gold is the most important and the oldest fibrous plant that is suitable for cultivation in arid and semi-arid regions. Among industrial plants, cotton has a special position. Not only cotton is one of the most important fibrous plants in view of fiber production, but also its seeds, which contain oil and protein, play a major role in providing edible oils and animal feed. Due to increasing need of society for cotton plant products and the importance of cotton in the global market and industries, it is very important to remove barriers to the continuous development of the cultivation of this product. Considering the importance of cotton in crop rotation and the sever reduction of cotton cultivation in recent years, it is necessary to use new approaches to increase the cultivation area, production amount and to reduce the production cost of this strategic crop. One of the strategies for developing the area under cotton cultivation is delayed cultivation as transplanting, which increases yield, early maturity and water use efficiency. Proper irrigation scheduling plays a very important role in delayed cultivations. In order to determine the physical and chemical properties of the soil in the study area, soil samples were taken from a depth of 0 to 30 and 30 to 60 cm and were analyzed in the laboratory. Fertilizer recommendation was done on the bases of soil test. In this experiment, the percentage of saturation moisture, electrical conductivity, acidity of saturated paste was determined and soil texture was measured by hydrometric method. Therefore, an experimental design of factorial strip plot, with three replications, was carried out in the Hashemabad cotton research station, in 2020. Irrigation methods of tape and furrow were as main factor. Cultivation methods of direct and transplanting as sub-factor and sub-sub factor was irrigation intervals after 70, 105, 140 mm cumulative evaporation from the pan, and irrigation quantities of 0, 50, 75, 100, 125% of the evaporated water from the pan. The treatment of 105 mm cumulative evaporation from the pan is usually 14 days, depending on the region. While the treatment of 70 mm means irrigating as soon as possible during 8 days. In addition, the treatment of irrigation after 140 mm of cumulative evaporation from the evaporation pan, ie once every 20 days, means that irrigation leads to plant stress. It should be noted that irrigation with less than 50% of the evaporated water from the pan can reduce the yield and is not applicable to the furrow irrigation method in the field, due to water not reaching the end of the field. In addition, irrigation with more than 125% of water evaporated from the pan is not highly recommended. The results showed that irrigation method had no effect on yield and yield components, but transplanting method had higher yield, early maturity, boll weight and water use efficiency at rates of 14, 180, 4.8 and 11.3% compared with direct method, respectively. Among the irrigation interval treatments, the irrigation after 105 mm evaporation from the pan had higher yield, boll weight and water use efficiency than the 70 and 140 mm treatments; So, that the yield of this treatment was 8.8 and 16.6% higher than the 70 and 140 mm treatments. While, water use efficiency of 105 mm treatment was 9% higher than 140 mm. In fact, cotton is a plant that reacts a lot to the amount and frequency of irrigation. It means irrigation management, and the balance between reproductive and vegetative growth is regulated by irrigation management. Excessive irrigation not only prevents increased yield, but also reduces yield and water use efficiency. Different irrigation water quantities had no effect on yield but on yield components had significant effect. The highest water use efficiency was related to 50% irrigation water, which was 19.6%, 43% and 69.8% higher than 75, 100 and 125% irrigation water, respectively. Irrigation quantity of more than 50% does not significantly increase yield but increases water use efficiency. Finally, the best treatment was transplanting method with an irrigation interval of 105 mm evaporation from the pan and 50% irrigation water of cotton increases. Also, transplanting cultivation increased yield compared to direct cultivation. Although it is not economically viable, it is recommended if the price of cotton increases.

Sewage collection network is one of the largest and most valuable infrastructure assets. Therefore, managing the wastewater collection network faces many challenges. Unfortunately, due to the extent of the damaged wastewater collection network and time and budget constraints, it is not possible in practice to treat and eliminate all wastewater collection system damages at the same time. So, this issue requires management activities in the form of vulnerability rating, to develop a maintenance program for sewage collection system maintenance. The present study evaluated and ranked the vulnerability of the sewerage network implemented in a part of District 5 of Tehran Municipality using a combination of Analytic Hierarchy Process (AHP) and GIS technique. AHP is one of the most efficient multi-criteria decision-making techniques, in this method, the factors are compared with each other in pairs and the highest weight is given to the layer that has the maximum effect on goal setting. In this regard, according to the opinion of experts and literature review, all types of possible damage to the sewage collection network at three levels of manhole, pipeline and branch were investigated and classified. In order to determine the relative importance of the defects, a questionnaire was prepared and distributed amongst experts working in the field of design and maintenance of sewage systems. Using AHP method, pairwise comparison between the relevant factors was performed and the relative weight of each criterion was calculated. After calculating the inconsistency ratio and confirming the meaningfulness of the judgement matrices of effective factors, the final weight of each criterion was applied to the corresponding layers to prepare the zoning map of the area. Next, judgement matrices were transferred to ArcGIS software and raster output was generated from them. The raster layers of different factors in ArcGIS software were homogenized and then combined using Fuzzy Membership method. In fact, the ultimate goal of the GIS technique used in this study was to obtaine the final overlap of all factors affecting the vulnerability of the sewage collection network (at two levels of manhole and pipeline clogging) and provide a zoning map of damages in the study network. It is important to note that the transformed raster maps for each of the effective factors have different units that must be scaled to the fuzzy membership method. As a result, all values scaled between 0 and 1 range. In general, each number in this range indicates the strength of membership in a set, based on a specific fuzzy algorithm. Next, the Fuzzy Membership command was run to obtain fuzzy the classified raster, from the Spatial Analyst Tools toolbox and the Overlay menu. Thus, fuzzy raster of quantitative criteria affecting the vulnerability of the sewage collection network was obtained. Weighted Overlay method was used to correctly apply the resulted weights and present the final model in ArcGIS. Thus, the fuzzy raster was added to the Spatial Analyst Tools toolbox and the Overlay menu, using the Weighted Sum command. Then, the aggregation of the obtained weights revealed the total weight of each of the target factors. Finally, the vulnerability zoning map of the sewage collection network was prepared in two levels of manhole and pipeline. According to the results, the probability of failure of the implemented manholes was very low and more than 70% of the manholes were classified in the category of low and very low damage. One of the possible reasons for this could be the young age and the principled implementation of the sewage collection network. The final overlap of the factors and sub-criteria affecting the vulnerability of the sewerage network indicated that the probability of destruction of pipelines was very low. More than 74% of the sewerage collection pipeline implemented in the case study area was classified in the category of low and medium damage. The results showed that only 30 wastewater transfer pipelines (about 7% of the whole network) were in critical conditions that should be given more attention. It could be considered that the small number of critical pipelines was due to the short life of the implemented pipelines. Based on the results, among the three target factors (manhole, pipeline and branch), the highest vulnerability of the sewerage collection network was related to the pipeline blockage. Also, the defects of the operational defects in all three levels of manhole, pipeline and branch clogging was the most affecting factor and have the highest impact.

Differences in climatic conditions, rainfall, transpiration of plant and evaporation from soil surface cause changes in yield production and crop water requirement. Due to the limitations of field assessment of plant growth, use of growth models can be a suitable tool for the study of plant behavior under different management conditions. Depending on different purposes over time, different models, including AquaCrop have implemented. Growth simulation methods are used to develop a sustainable strategy of water distribution, during the growing season, for achieving the best performance in reducing water consumption. Colza as a strategic product with high economic value is one of the main priorities in the cultivation pattern of the plains with different weather conditions. Therefore, this study was conducted to simulate a colza growth model and find the sustainable irrigation plans and groundwater allocation strategy, using crop growth simulation in four different climatic regions of Iran. This study aims to collect farm information and develop the colza crop growth pattern in four climatic regions of Iran. The experimental farms were located in Birjand, Bushehr, Shahrekord and Gorgan with arid, semi-arid, semi-wet and wet conditions, respectively. Simulation was performed to measure the level of canopy cover with the aim of achieving the final yield of the crop by AquaCrop software in the 2018-19 crop season. The information required to calibrate the AquaCrop model (including cultivation parameters, plant characteristics, growth schedule and soil texture) was entered into the model and calibrated to achieve actual crop yield. One of the main components of modeling is the daily estimation of soil moisture, which affects the water requirement, root growth rate and canopy cover of the plant, and thus the final yield production. Understanding the relationship between water, soil and plants has expanded widely since the presentation of the relationship between Doorenbos and Kassam (1979). The need to increase water productivity as a tool for water scarcity has led the Food and Agriculture Organization of the United Nations (FAO) to develop the AquaCrop model to simulate the response of crops to the amount of water consumed. Water productivity (kg/m3) is expressed as the ratio of final crop yield (kg/ha) and irrigation water (m 3/ha). Moreover, different scenarios of groundwater allocation were considered to supply crop water requirement, using soil water balance model in the root zone. The results showed that the highest amount of plant transpiration was obtained in Bushehr, Birjand, Shahrekord and Gorgan farms with a total of 900, 790, 717 and 407 mm, respectively. The highest yield was estimated in Shahrekord with more than 1800 kg/ha and the highest irrigation water productivity in Gorgan with 0.26 kg/m3. The results also showed that cultivation of colza at the beginning of the autumn planting period in each region increases the use of precipitation for canopy growth and thus reduces irrigation water consumption at the end of the season and increases productivity. Among the studied areas, the best range was related to Shahrekord colza cultivation with long growth period, acceptable yield, adaptive climatic conditions and suitable rainfall distribution for rainfed cultivation. The planting date is one of the effective management parameters in increasing water use productivity and effective use of rainfall. Therefore, the modeling results estimated an average decrease of about 10% in plant water requirements and a 1% increase in water productivity due to a ten-day reduction in planting date compared with the experiments performed. Notably, this crop is planted alternately with crops such as rice and cereals and the spring crop which generally has a higher economic value; also there is a limitation after harvest to prepare the field regarding the planting date. Therefore, attention to crop rotation and the possibility of changing and managing the time of planting and harvesting the first crop should also be studied. Effective use of rainwater, especially in areas such as Birjand and Bushehr, where water constraints are the main cause of reduced performance can be considered by relying on planning based on daily information. Differences in plant transpiration rate in daily, weekly and monthly scales indicate that irrigation intervals in Bushehr should be done with irrigation intervals of less than seven days at the end of the growing season to complete the flowers and fill the seeds with increased yield. In addition to rainfed cultivation for Golestan area, rainfed cultivation with supplementary irrigation at the end of the growing season is recommended for climatic conditions near Shahrekord and sprinkler irrigation for arid areas.

In recent decades, urban, industrial and agricultural development has led to growing challenges in water resources supply. The challenge has deepened due to natural hydrological variability, severe droughts, climate change and inadequate water resources management policies. Thus, we are witnessing more and more conflicts among water users over limited water resources. Such conflicts are more intense in inter-basin water transfer projects which are often costly and affect water rights and interests of numerous water users. Due to the complexity of process, it is very important for water policy makers in such projects to rely on a tool for decision making. Sustainable development can be considered as an appropriate approach in this process based on existing needs, without conflicting with the needs of future generations. In this research, an experimental method has been adopted for assessing sustainability in a large-scale and controversial water transfer plan in central Iran, called Behesht-Abad. Sustainable development can be considered from different aspects, one of which can be taken into account as conflict stability and the other as hydrological sustainability. The first one can be evaluated by the concepts of stability definitions in non-cooperative game theories. Non-cooperative game theory involves a stability analysis in order to show which stability definition determine the behavior of the two players as source and recipient basins. If all players achieve a stable solution, they do not move from that condition and the situation remains stable. It is also necessary to evaluate each player's priorities and their choices and solutions in relation to the water transfer project to develop a conflict model. A conflict model called GMCR+ was executed to analyze various solutions and scenarios between the two players. GMCR+ generated a list of all possible states, whereas infeasible states were removed after evaluating the produced scenarios. Then, the most stable scenarios among various solutions are selected in terms of cooperative and non-cooperative scenarios. In the next step, the hydrological sustainability of the selected scenarios must be examined. Sustainability can be quantified by various multidimensional indicators. However, the largest problem is to interpret the combination of all these indicators in such projects. Various methods of aggregating could be applied to achieve composite indicators to help this problem. Development of composite indicators may be beneficial in such large-scale inter-basin water transfer project. Aggregating indicators involves multivariate analysis, data standardization, assignment of weights, and applying different methods of aggregating. In this study, 10 indicators of sustainability in three dimensions of economic, social and environmental were used, which finally turn into four composite indicators to obtain a robust analysis. Then, the hydrological sustainability of the two basins in the selected scenarios based on the composite indicators of sustainability (CIS) was investigated through a simulation model. MODSIM simulation model was adopted to simulate the selected scenarios. Also, a multivariate statistical method such as principal component analysis (PCA) was performed to determine the main indicators in the source and recipient basins. Comparative analysis of the individual CIS was performed to prove whether they are really delivering the same concept of sustainability in inter-basin water transfer. Correlations analysis among the composite indicators showed that they were normally distributed, so Pearson's ratio was utilized as a test of parametric correlation. The results revealed that using various methods to construct composite indicators can help further to analyze the dimensions of such large-scale projects. According to PCA method, all selected indicators were essential for extracting CIS approaches and none of them could be ignored. The results also indicated positive and significant correlations between more CISs. However, it depended on the kind of method used for weighting and aggregating methods. In addition, despite stability of the region, the hydrological sustainability of the two basins did not seem to be appropriate. Although obtaining revenue for source basin seemed fair in point view of the game theory analysis, the hydrological sustainability was reduced in every four applied methods. The recipient basin would not be in a better condition. The results showed, the hydrological sustainability of the recipient basin would not increase significantly due to the use of transferred water in projects development and lack of supply and demand management. Therefore, transferred water for a short time might solve the problem of water shortage in recipient basin, but in the long run, problem would return more seriously.

Today, streamflow prediction is considered as one of the basic components of water resources systems. This is important as climate change and human activities could affect hydrological processes which lead to major changes in water distribution. According to the fifth IPCC report, frequent use of greenhouse gases could indirectly change the natural flow patterns by rising surface temperature. Variable flow patterns eventually causes serious challenges in reservoir operation, since it uses past-oriented rule curves. As a result, the performance may decrease due to the future possible changes in streamflow patterns as an input of system. To solve this problem, a wide range of recent studies have proposed a hybrid platform to incorporate flow prediction into operation policies. However, the impacts of forecasts accuracy on operation performances have not yet been fully investigated. In other words, it is not possible to make an accurate estimation of operation outcomes commensurate with forecast accuracy. Accordingly, the purpose of this study is to develop a monthly forecast model and investigate the effects of corresponding accuracy on the operation performances. The general structure of this article consisted of two steps. In the first step, to develop a forecast model two methods were proposed: 1-Autocorrelation and 2-Ensemble learning. In the autocorrelation method, the discrete wavelet transform was used to decompose the streamflow time series. Next, each component was predicted independently using artificial neural network and autocorrelation function. While in the ensemble learning, the target was to have a direct estimation of coming streamflow. So, the wrapper method was used to identify the effective components amongst decomposed parameters. Then, all these effective components were combined using Adaboost algorithm to improve training process and have a better estimation for coming streamflow. Finally, the best forecast model was selected against some evaluation indices. In the second step, three conventional reservoir operation policies including polynomial, hedging and standard operation policies were introduced and combined with forecast model. In other words, an independent flow term was added in the rule curve relation to evaluate the corresponding impacts on operation. Finally, comparing some operation criteria using forecast and observed flow revealed the effects of forecast accuracy on the operation performance. The results showed that in the second method, the correlation coefficient R reached the highest value equal to 0.957. This number indicated a suitable linear performance against observed data. It was also deduced that the Willmott index behaved similarly and recorded the highest value above 0.971. Indeed, from the Nash perspective second approach was so satisfactory. Besides, flow simulation diagram showed poor performance of peak estimation in two methods which might originated due to little peak samples. In other words, as artificial neural network was a data-driven model and dependent to the size of sample data, so the small number of peak records led to poor peak estimation. Another point was about the role of preprocessing on indices improvement. Upon closer inspection, it was found that the Willmot index was the least effective against preprocessing, so that the highest change in the second approach was recorded at about 16%. Also using box and whisker chart showed that the data range of second method was more similar to the observed data. In addition, the minimum, maximum, and median values of this method were closer to the corresponding observed values and skewed to upper records. At the end, according to the results, the ensemble learning method was selected as the forecast model to be coupled with simulation-optimization model. In a polynomial rule curve, the simulation results indicated the direct effects of forecast component on the relative deficit reduction. Also, it can be seen that 4% improvement in R, which means the use of real observed data, reduced a relative deficit to 10%. In addition, in case of 2% and 10% improvement in WI and Nash indices, the same 10% in relative deficit could be expected. Therefore, it should be noted that the performance of a polynomial rule curve was more sensitive to the WI compared with R and Nash. The results also showed better performance of the coupled model in other evaluation indices such as reliability, quantitative reliability and maximum vulnerability of 5%, 5% and 1.3%, respectively. Comparing indices variation, it was observed that the relative deficit was more sensitive to the performance of forecast model and in opposite the maximum vulnerability was the least sensitive index to forecast. This could be traced to its nature, as this index was the maximum amount of monthly relative deficit and improvement in any values means a significant reduction in monthly vulnerability. However, the 5% improvement in quantitative reliability means the awareness of possible flows leading to clever release met more needs and caused more comprehensive management. Similarly, positive impacts of forecast accuracy were observed in hedging policy, as 4% variation in R reduced the deficit to 13% and improved reliability, quantitative reliability and maximum vulnerability of 6.2%, 5.3% and 1.4%, respectively. Aggregation of forecast term into the rule curve relation also resulted in better operational performance versus the standard policy. Finally, it turned out that hedging policy was more sensitive against forecasting accuracy.

Land use change is one of the most important factors affecting runoff from the basin, which changes the factors affecting water infiltration. According to the statistics collected by the Forests Organization, from the beginning of 2011 to the first six months of 2015, 552 floods occurred in Iran. Land use change is one of the important factors in changing hydrological flow, basin erosion and biodiversity destruction. Lack of attention to land use change and exploitation of natural resources due to disturbing the biological balance has been one of the effective factors in increasing flood zones. Therefore, it is possible to take a step towards equilibrium by knowing the trend of land use changes in order to lead ecosystems and simulate the hydrological reaction of the watershed with less error. Mathematical models have a great ability to estimate runoff and its flood plain and provide users with effective information by recognizing the factors and parameters affecting the flood. Such models provide the relevant managers and experts with considerable ability to manage the basin before floods, and even crisis management and rescue during floods. In this study, in order to investigate the effect of land use changes on hydrological characteristics, for an approximate distances of 40 km from the Kashkan River in Lorestan Province, first land use maps for 1989 and 2014 were extracted using satellite images of 5 and 8 June of the years 1989 (TMC1) and 2014 (Landsat8) with a spatial resolution of 30 m. Then, the number of the basin curve and lag time were measured using the help maps in order to calculate the runoff height in the hydrological model. On the other hand, the runoff precipitation simulation was performed through considerin other required parameters. In order to correspond to the land use extraction periods, two normal periods related to 1989 and 2014 were selected for simulation. To evaluate the efficiency of the model in simulating daily flood values, the coefficient of determination error criteria (R2), dispersion index (SI), volume error percentage (V%), peak error value (  %), and error peak time ( ) were considered. In the next step, in order to locate and adapt different land uses to flood plains in different return periods; the flood maps of these zones were extracted in different return periods and placed on land use change maps. And the area of land uses in different return periods was calculated for the studied periods. In order to achieve this goal, the first step involves preparing input information for HEC-RAS software. To prepare the required geometric layers of RAS and calculate the flood plains, the TIN of the area from a 1:150 digital map (mapped by Lorestan Regional Water Organization) was prepared and in order to achieve the peak discharge with different return periods, two 18-year statistical periods (from 1972 to 1990 and from 1999 to 2017), and maximum instantaneous discharge of Doab Veysian hydrometric station were used. The Manning coefficient was determined by using Cowan's (1956) method and geometric data. This data includes obstacles and structures in flow path that obtains and simulated in software. To analyze the flow in a steady way, the HEC-RAS software and HEC-geo-RAS extension in Arc-GIS environment have been used. The EasyFit software has been used to prepare peak discharges for different return periods. The results of land use changes during the period of 1989-2014 have shown that the area of land uses such as rangelands and forests has decreased and the area of land uses such as wastelands and human structures has increased. As a result, the value of the calculated curve number has increased from 45 to 68.4, and the lag time has increased from 41 to 24.3 mm, which indicates the flooding of the basin. The area of different uses on the flood maps in the period of different returns showed the residential areas in the new period compared to the old period, which were flooded in the 50-year return period. They are now flooded due to increase in the flood discharge and the development of rural areas along the river during a short 25-year return period; Even the new farms in the river side is danger of flood in shorter period such as 10-year.

In recent years, inter-basin water transfer is inevitable due to an increase in population cities and inappropriate spatial water resources distribution and is considering as a way for dealing with water shortage. Regarding the complexity of these projects caused by various factors of getting involved such as environmental issues, right of water and water balance, social conflicts and immigration, decision-making with regard to the effects of inter-basin water transfer is very important. The increasing need for water resources for various purposes, such as agriculture, drinking and industry, has faced many difficulties and limitations in achieving available and usable water. In such circumstances, inter-basin water-transfer plans have become part of the country's management policies to provide new water resources. In these projects, the capacities of the source and destination basins may not be properly evaluated, despite the variety of multi-criteria decision-making methods that determine the best option considering all effective decision-making criteria. These methods have not yet been used appropriately in national executive and infrastructure projects such as inter-basin water transfer in Iran. Based on literature review on various political, security, social, cultural, economic and environmental dimensions, the negative and positive effects of the inter-basins water transfer could be assessed by Fuzzy inference system. Proponents and critics of the water transfer projects mostly focus on the negative environmental consequences. From a social and political viewpoint, the inter-basin water transfer has positive outcomes that could be leading to an increase in social capital and avoid conflicts. Therefore, water transfer could be the origin of many changes in origin and destination basins that should be assessed by different viewpoints and considering technical, economic and environmental aspects and emphasis on the social and political assumptions. Hence, the water transfer project is feasible when technical ability and also environmental evaluation were confirmed. In this research, on the basis of problem’s nature, decision-making criteria were identified. The applied criteria in water resources researches returns to benefit-cost ratio calculation. Employment factor is another key factor that could have an important role in selection of the best project. Also, regrading to people's welcome and their satisfaction from execution of the project, this criterion was also very important. The main decision-making criteria were defined based on investigating different sources. Fourteen studied criteria were assessed independently in decision-making matrix, including: Land acquisition, induction earthquake, migration, water quality depletion and pollution of water resources, springs and wells, dam geology problems, reservoir geology problems, transmission line problems, current costs, capital costs, production energy, consumption energy, ease of use, and duration of project implementation. The decision matrix was formed by determining the values of each criterion for each option. In the second case, the sub-criteria were defined and each criterion was subdivided into several sub-criteria. Then, the model developed by matrix along with the sub-criteria. The following criteria were defined as follows:  (1) Social: Including 3 subgroups of land acquisition, earthquake induction and migration; (2) Environment: Includes 2 subgroups of water quality depletion and contamination of water resources and drying of wells and springs; (3) Geological and Executive Problems: Includes 3 subgroups of dam geology problems, reservoir geology problems, and transmission line implementation problems; (4) Economic: Includes 4 subcategories of the current cost, capital cost, energy consumption and production energy; (5) Ease of operation; (6) Duration of project implementation. Fuzzy inference system method is one of the most widely used multi-criteria decision making methods and in this research, the inter-basin water transfer scheme in Beheshtabad in Chaharmahal-and-Bakhtiari province has been investigated by the fuzzy inference system and hierarchical analysis methods. The purpose of this study is to apply the fuzzy inference system method to evaluate the suitable option of Beheshtabad Basin Water Transmission System considering 14 quantitative and qualitative criteria. Pairwise comparisons were carried out according to experts and then 14 criteria were ranked using hierarchical analysis of multi criteria and the best option for water transfer was selected based on fuzzy inference system method. The results showed that the first option is superior to the others and also the current cost and capital cost were the most important criteria; while, the reservoir geological problems criterion was introduced as the least important one. The second option with a confidence level of 86.9% based on fuzzy decision making was recognized as desirable. The confidence level of the sixth option was 38.9% and the seventh option was 23.9%, based on the fuzzy method. Option seven was chosen as the lowest priority of Beheshtabad water transfer project, because it had a low numerical value according to many criteria.

In recent decades, the technique of systems analysis has attracted serious attention in planning and management of water resources. This research was based on the idea of modeling surface water resources and connecting them to the aquifer in the form of separate subsystems, taking into account the side factors. In fact, this study considered the interaction of surface and groundwater, using system simulation and integrated dynamic connection between surface and groundwater resources in the area. In other words, one of the innovative aspects of this research was the integrated management of surface and groundwater through the dynamic system method. System dynamics (SD) is among the available tools for simulating complex water resources systems, in which the links between the system elements are expressed as causal relationships. The SD-based software packages can serve as flexible and integrated tools for a wide range of modeling applications, from participatory modeling to economic analysis. First, the conceptual model and causal relationships between the effective parameters in the groundwater equations of the plain were prepared, and then the model was made in the Vensim software. Monthly data for water use and resources were imported to the model, in Excel format. Afterwards, the scenarios were designed and defined for the model. Finally, the performance of the catchment was examined in terms of meeting the desired needs and maintaining groundwater balance. Since the climate is continuously changing due to man-made activities, the output of GCM models was used in this research to assess the different management scenarios. So, the GFDL-ESM2M model was employed to predict the future rainfall, under the fifth average future climate scenarios (RCP4.5). The reason for choosing GFDL_ESM2M model was that it has been recently developed by NOAA to gain better understand of the Earth's biochemical cycle, including human actions and interaction with the climate system. Then, river runoff was simulated using derived rainfall in the time period of 2015 to 2030, through ARMAX statistical model. This runoff time series then was fed into the system dynamic model to assess the water balance of the study area under different management scenarios. This study was to evaluate the condition of the aquifer, apply recharge scenarios, and improve the groundwater storage system of the Nesa plain in Bam County, Iran. A comprehensive model was thus developed based on the SD approach. Within this system, the relationships and the feedback of the changes in the sub-systems were expressed using cause-and-effect diagrams. In order to implement the model, several scenarios were further considered alone or in combination with each other. Due to the outputs of the prepared model and regarding the priorities for allocation of the volume of water stored in the reservoir of the Nesa plain (supply of the drinking water for Bam city, and consumption of industry and services, respectively), water budget in the plain was negative. The water budget of the plain could reach - 65.4844 mcm, in the following 20 years, indicting the critical situation of the region. Given that about 4395 ha of the lands in the region were under the predominant cultivation of alfalfa (approximately 60%) and wheat (about 30%) with a total of 60 mcm of water consumption. modifying the cultivation pattern (eliminating the cultivation of these crops) alone had no significant impact on water balance. Installation of volume meters and implementation of well regulation policy to about 75% of current permits would thus boost the water balance of the region to -44.84 mcm. Via artificial recharging of the plain by flood spreading method, the budget of water resources was equal to -35.17 mcm, which implies the success of the combined policy. Therefore, the application of regulatory policies and the implementation of modern irrigation systems, especially for date orchards (as the main crop in the region) with an annual consumption of about 2300 mcm/ha, and preventing the drilling of more wells could be steps towards balancing the water resources in the region. This could not be possible except through the cooperation of stakeholders and beneficiaries along with the implementation of support packages. In general, assessing the process of flood spreading, recharging the groundwater aquifers, raising the water level of wells, increasing the discharge of springs and canals, improving the quality of the groundwater, and meeting the satisfaction of local communities will bring about a decrease in urbanization and rural prosperity.

Rice is one of the most important food products for more than 50% of the world's population (more than 3.5 billion people). This plant is one of the crops that can be cultivated in various ways in different areas of the world. In most areas, rice is traditionally grown by transplanting seedlings into puddled field known as puddled transplanted rice (TPR). The other method of cultivation of this plant is dry seeded rice (DSR). While, direct dry seeded rice (DDSR) is the direct cultivation of rice seeds in a dry, non-submerged bed, without plowing and mulching. Other benefits of this method, in order to implement sustainable agriculture, can be mentioned as: reducing the movement of agricultural machinery on the farm, developing crop rotation, reducing environmental pollution and greenhouse gases, increasing the efficiency of consumption of high-consumption fertilizers and micronutrients. Regarding the worldwide prevalence of DDSR and some successful experiences in Golestan and Khuzestan Provinces, Iran, the current study was conducted to investigate the possibility of dry direct seeded rice by trickle irrigation (T-tape). A field study was conducted using split plots based on randomized complete block with 3 replications at Lenjan region, Isfahan Prov., during 2019-2020. Main plots included drip irrigation at 80, 100, and 120×pan (E-pan) which were called I1, I2 and I3, respectively and flood irrigation (I4) as a control. Two cultivars of Sazandegi rice and line No. 2 were considered as sub plots. The dimensions of the main plots and the sub-plots were 20 × 5.5 meter and 20 × 2.5 meter, respectively. All amount of phosphorus and potassium fertilizers and one third of nitrogen fertilizers were used at the time of bed preparation. In addition, the remaining two thirds of urea was divided and consumed equally during tillering and flowering stages. During the period of plant growth, the amount of irrigation water was calculated and applied based on the cumulative evaporation from the Class A evaporation pan. For this purpose, by installing a Class A evaporation pan at the project site, the amount of daily evaporation was calculated and by considering the relevant coefficients, the amount of irrigation water depth was calculated and performed. Statistical analyzes and graphs were performed using SAS ver. 9.1, Excel software and comparisons of means were performed using Duncan's multiple range test. The results showed that grain yield, water consumption and irrigation water use efficiency were significantly affected by irrigation regimes. The maximum grain yield (4709.8 kg. ha-1) was obtained in treatment I4 which was 59.31%, 25.60% and 17.72% higher than the grain yield in treatments (I1), (I2) and (I3), respectively. The higher yield in continues flooding treatment can be attributed to the absence of drought stress in this treatment, as well as higher number of full seeds per panicle and 1000-grain weight, reduction of percentage of porosity and more effective weed control. Comparison of means showed that the maximum water consumption (21008.3 m3. ha-1) in continues flooding treatment and the minimum (8193.3 m3. ha-1) in irrigation treatment based on 80% evaporation from evaporation pan occurred. The reduction of water consumption in drought treatments was mainly due to the reduction of deep and lateral infiltration of water into the soil and the reduction of evaporation rate, which has been mentioned in other studies. This was while the highest rate of water saving in treatments (I1), (I2) and (I3) was equal to 61.00%, 50.95% and 41.21%, respectively, compared to the control treatment. In addition, the maximum efficiency of irrigation water consumption was calculated in treatments (I1), (I2), (I3) and (I4) to be 0.34, 0.34, 0.31 and 0.22 kg.m-3, respectively. The results also showed that drought treatment led to a decrease in plant height, plant tillering power, total number of paws and the number of fertile paws per unit area. The maximum plant height was obtained in the treatment of continues flooding of plants (99.11 cm), while the height in drought treatments with an average height of 85.3 cm showed a decrease of about 13%. Based on the results of this study, grain yield and optimal irrigation water efficiency obtained in treatment (I3) indicated that Dry Direct-Seeded rice can be used as a substitute for continues flooding of rice to increase production and save water consumption.

Iran is one of the countries exposed to many natural disasters, of which the flood phenomenon is one of the most serious. According to official statistics, more than 50% of casualties due to natural disasters in Iran are due to floods. Accurate and timely information is needed to plan any flood management measures. Currently, many researchers have examined the methods of obtaining water area information. Among these methods, land use classification and change analysis are the most important applications of remote sensing techniques. One of the most widely practical classifications is the separation of water class from other classes.Also, Landsat images are one of the most common data sources in this field. In this regard researches have been done in the field of identifying water areas, due to its high importance in flood crisis management with the advancement of satellite technology in remote sensing. In this study, an automated method has been developed to prepare flood change maps and use different capabilities of different water and humidity indicators to provide automated training data. This can reduce the challenge of operator interferences. Besides, the efficiency of the high level of automation in the extraction of flooded areas in accelerating and facilitating the management of this crisis is indisputable. Therefore, when manual training data is not available, applying a fully automated approach will be helpful. The integration of indicators can also be effective in improving the accuracy of existing water indicators. Floods are one of the most important natural disasters in the world that occurred due to different factors such as human encroachment on rivers and vegetation damages. The purpose of this study is to develop an automated method for preparing training data for supervised classification of images and using the capabilities of integrated indicators to identify flooded areas. Therefore, several approaches for flood in Golestan province, 2019, were implemented by Landsat-8 data and the results of each were examined. The Kmeans clustering algorithm, Otsu, Multi and Adaptive thresholds were used to generate automated training data based on different water indices (NDWI, AWEI and MNDWI; Then the ANN, SVM, ML, MD and BE classifications) was implemented to monitor flood changes. The results compared with the manual classification method indicated that the proposed approach, in addition to providing a high-level of automation in monitoring changes, also had high efficiency and accuracy. In another development approach, different water and moisture indices were combined with the aim of improving the production process of automated training data. Among the 85 tests performed, the combined approaches had the highest accuracy. Due to the nature of different water indicators, their selection and appropriate combination, in addition to reducing the noise in the water indicator image was also effective in increasing the ability to identify impure water areas. Finally, a comprehensive deductive analysis of automated methods and hybrid indicators was carried out to help to manage flood crisis, facilitate and accelerate the process. It can be said that with the advancement of technology and the emergence of various aerial / satellite images, many opportunities and possibilities have been created for effective and sustainable management. One of the best ways to extract information from digital images is to classify the image. One of the challenges in image classification is to reduce the interference of users using algorithms that have high level of automation. This issue has high importance due to the sensitivity and sudden occurrence of the flood crisis. Therefore, to promote this challenge, in this research, an automated and efficient approach for supervised classifications with emphasis on automatic production of training data to prepare a map of flood changes is presented. In total, 85 different studies were performed to obtain flood change maps, using hybrid and non-hybrid automated methods to prepare automated training data for supervised classifications. It is considered that the obtained results had acceptable accuracy. For example, in all approaches studied, ANN classification offered better accuracy, which could be seen from the diagrams provided. Also, due to the lack of significant difference in the accuracy of the maps, obtained from this classification with different indicators and thresholds, it can be said that this classification is also highly robust. The results indicate that ANN classification in combined approaches with Otsu and Adaptive thresholds has the highest accuracy and maximum robustness. In comparison with methods related to execution speed, ML and MD classifications also provided good performance. However, the difference in the accuracy of these classifications compared to the ANN classification is not significant in some cases and will be possible to replace due to higher execution speed. Finally, by analysis of the results, it can be stated that the automated approaches proposed in this research can be replaced by traditional classification methods.

Arid and semi-arid regions always face the challenges of food security, ecosystem sustainability and, consequently, increased water productivity. Crop water productivity can be used as a suitable indicator to identify areas prone to cultivate a particular crop in these areas. In return, identifying and selecting suitable cultivation areas will help increase productivity. Selecting suitable areas for cultivation is not enough to achieve high crop water productivity. Using appropriate management scenarios to achieve this goal is essential. Deficit irrigation is one of the management strategies to increase water productivity. Investigating the effect of various management scenarios on water productivity in the field studies will be time-consuming and costly. The computer models could be used as tools to simulate the effects of management scenarios on crop yield and water productivity. So far, various crop growth simulation models have been developed and used to investigate the impacts of management scenarios on crop water productivity. In large-scale decision and policy-making, the growing conditions of crops in different farms are not the same. Most of crop growth simulation models are designed for point and field scales, and for large-scale use, the use of auxiliary tools such as GIS is essential. Agricultural activities are the most important means of livelihood for a large number of people in Kermanshah province. According to the Jihad Agricultural Organization, this province is a leading province in terms of the area under cultivation of crops. Soybean is a raw material for the production of many food products and an important source of vegetable oils and proteins which could be a good choice for the farmers of this province. This study was performed to investigate temporal and spatial variations of soybean water productivity, under different irrigation scenarios, in Gavshan irrigation and drainage network –Razavar river- Kermanshah and Kordestan provinces, as an important indicator to identify areas suitable for the cultivation of this crop. For this purpose, a GIS-based software (for presentation and analyzing spatial data), was used along with a tool called Reference Weather from the Crop Growth Monitoring System (for weather data interpolation) and AquaCrop software plug-in version (for simulating scenarios). The study area was divided into 37 regular grids of 5 by 5 km. Based on the available soil reports, 24 homogeneous soil units were identified in the study area. Then to simulate a model, 94 homogeneous units were delineated by overlaying of grid weathers and soil units. For each grid of weather, daily reference crop evapotranspiration was calculated using the Penman-Monteith equation based on daily weather data (1988-2015). The files required to run the AquaCrop model were prepared based on the available information for each homogeneous unit. Then, soybean growth was simulated under 3 irrigation scenarios (60, 80 and 100% potential irrigation requirement) for all homogeneous units, and for 28 years (1988-2015), using a calibrated model. For these simulations, 7896 projects were prepared and implemented with the AquaCrop plug-in version. The results showed that grain yield, seasonal evapotranspiration and consequently soybean water productivity are affected by irrigation scenarios. The mean grain yield, seasonal evapotranspiration, and water productivity under 60% irrigation scenario decreased to 56.64, 30.76, and 37.78% relative to the full irrigation scenario, respectively. The results also indicated that these parameters had temporal and spatial variations. These changes increased with increasing water stress intensity (except for temporal changes in seasonal evapotranspiration) in irrigation scenarios. The reason for temporal changes in the studied parameters can be due to annual changes in weather parameters (temperature, precipitation, sundial, etc.). But, spatial changes are due to the simultaneous effect of spatial changes in climatic and soil conditions (water holding capacity, topography, hydraulic conductivity, etc.) and their interactions on each other. With increasing water stress intensity, the annual fluctuations of seasonal evapotranspiration decreased. The reason for this is the dependence of seasonal evapotranspiration on the growth period and air temperature, which does the opposite. In general, the average water productivity of soybean in Mian-Darband plain was higher than in Bile-var plain. According to simulated water productivity, B1 and B4 irrigation zones in the Bile-var plain, and D4 and D9 irrigation zones in Mian-Darband plain were more suitable to soybean cultivation from the point of view of water productivity, which is the key factor in arid and semi-arid climate of Iran.

Preferential flow is formed through large pores in soil. The flow transmission in the large pores is faster than the regular parts of soil. Therefore, the effect of preferential flows, which are created by factors such as cracks, should be assessed on the distribution of moisture profile. The analytic, empirical and quantitative models can be used to assess the various modeling parameters and water distribution in soil in various environmental conditions, in order to save money and time. Hydrus-2D model is one of the potent models for stimulating the movements of water and salts in soil, based on the Richards' equation numerical solution. Nowadays, the use of deficit irrigation methods is increasing due to the water resources shortage. In addition, the preferential flows creating in farms have an important role in water and contaminant transport. Therefore, the purpose of this study is to investigate the effect of pore geometry (with different width and depth) on soil moisture distribution in soil profiles, at different levels of irrigation. To investigate the effect of preferential flow on soil moisture profile, sandy and sandy loam texture (in the preferred area) was used. In this study, column with a diameter of 160 mm and a length of 350 mm were applied. The soil columns were filled in layers. The method of Wang et al. (2013) was employed to establish the preferential flow. Due to this method, the columns were placed in the water container from the floor and a pipe with a diameter of 16 mm and a height of 350 mm was placed in the center of the column. The soil was poured in layers around a 16 mm pipe and after each layer a little water was sprinkled on the soil surface. After filling the soil column, the 16 mm tube was gently pulled out of the larger column, and then the 16 mm tube was filled with find grain sand (treatment T1). Irrigation levels of 120, 100, 80 and 60% were selected (T120, T100, T80 and T60, respectively). The initial soil moisture of the treatments was the lower limit of readily available water. The T80 and T60 treatments had 20 and 40% less irrigation volume and T120 treatment had 20% more than the T100 treatment, respectively. The RETC software was used to estimate the Van-Genuchten coefficients. To calibrate the Van-Genuchten equation coefficients, soil moisture profiles were used in Hydrus. The model initial conditions were the initial soil water content at different depths. To compare the amount of simulation and observational values, the root mean square error (RMSE), NRMSE and correlation coefficient (r) were used. The Hydrus-2D software was employed to investigate the soil moisture distribution under different geometric shapes of the preferential flow (PF). The PF’s geometries created in V-shaped pores from the soil surface to deep where the top-width was 0.5, 1 and 1.5 cm (B0.5, B1, B1.5) and the total depth was 10, 20 and 30 cm (H10, H20, H30). In this study, the soil moisture was simulated with the Van-Genuchten coefficients. The results showed that the water content with the coefficients was estimated with a good accuracy. The minimum and maximum correlation coefficients were 0.83 and 0.95, respectively. The average percentage of moisture error at depths of 0 and 20 cm in the T60 and T120 was about 2% and the moisture content of the model was slightly different from the observed values. According to the research results, by increasing the depth of cracks, the amount of soil moisture in the soil surface decreases, compared with the non-cracked soils. Thus, the water transfers to the lower depths and consequently increases the soil moisture. In the deficit irrigation condition, the presence of preferential flow causes a more uniform soil moisture distribution in the soil profiles; But, the more irrigation level/ time increases the more deep percolation losses that finally decreases the irrigation efficiency. Some research result showed that PF in most farms has caused increasing deep percolation losses about 71%. Playan and Matthews (2004) evaluated irrigation efficiency by changing irrigation management. Their results showed that with decreasing irrigation time, irrigation water use efficiency increased from 44% to 71%. Also in their study, the soil moisture content at the soil surface in T60, T80, T100 and T120 treatments in the presence of the PF with depth of 30 cm (H30) and a width of 1.5 cm (B1.5), decreased about 11, 9.3, 9.2 and 9.1%, respectively, where the moisture at the depth of 20 cm increased about 24.1, 25, 27 and 21.1%, respectively. In our research, the results for different PF forms in T120 and T80 showed that the presence of a crack with low depth (h=10 cm), for all width scenario (B=0.5, 1 and 1.5 cm), had not a significant effect on the distribution of soil moisture profiles. For the PF with H=20 and H=30 cm, the effect of the crack width (B) on the soil moisture distribution in T80 became more noticeable at a distance of 3.5 cm from the center of the column. The amount of soil moisture in the soil profile did not differ much for the different crack’s width in T120 treatment, but with increasing the depth of the cracks (H20, H30), the moisture distribution at different depths became more uniform. The results of this study showed that with increasing the depth and width of the preferential flow, the moisture distribution is more uniform and the higher the irrigation level, the more uniform distribution is. This process decreases surface soil moisture and causes water flow to the lower depth in comparison with the non- preferential flow condition. For example, in the soil surface in treatments with irrigation levels of 60, 80, 100 and 120%, the amount of soil moisture at the soil surface, under preferential flow conditions with a depth of 30 cm and a width of 1.5 cm, was decreased around 11, 9.3, 9.2 and 9.1 %, respectively and it caused increase in the soil moisture at depth of 20 cm with 24.1, 25, 27 and 21.1 percent, respectively.