مجله آبیاری و زهکشی ایران
سال چهاردهم شماره 3 (امرداد و شهریور 1399)

Flood simulation using the hydrological model requires an appropriate rainfall dataset and unfortunately, in most parts of the Iran country the spatiotemporal resolution and density of ground gauges aren’t suitable. Hence, using remotely sensed high spatiotemporal resolution datasets can be useful for filling this gap. The main objective of this research is the assessment of PERSIANN-CCs hourly rainfall dataset for simulation of flood hydrograph using HEC-HMS event-based model at the Asalem river basin (ARB), Iran. Furthermore, to better evaluation of this model, three different spatial scenarios (including lumped, Thiessen and link-lumped) at 1, 3 and 6 hour time steps are used. Findings showed that using of link-lumped scenario at 3 and 6-hour time steps for simulation of flood hydrograph leads to the best results. For example, in this case, the average values of Nash-Sutcliffe efficiency (NSE) and Correlation Coefficient (CC) values for all events are about 0.58 and 0.78 (for Δt= 3 hr) and 0.56 and 0.74 (for Δt= 6 hr), respectively. Moreover, if the main purpose of modeling is the accurate estimation of peak flow, using the second spatial scenario leads to minimum error (with the relative error ranging between 0.2 and 7.6 %) at 1 and 3 hr time steps, while the third spatial scenario(link-lumped) hasn’t the required potential for simulation of peak flow. Also, combing the first spatial scenario and PERSIANN- CCs dataset is the best case for estimation of time to peak (Tp) which is very important in flood warning systems. Findings of this study indicate that in the lack of ground observations, the high spatiotemporal resolution rainfall datasets such as PERSIANN-CCs can be used for flood simulation.

Water is one of the most important factors limiting agricultural development in arid and semi-arid regions of the world. One of the most important issues in water management is to assess and determine the water requirement of plants. Water management, water resources and water requirements are essential for effective irrigation planning and efficient water resource management. In this way, Carla (bitter melon), which is the crop of the drug, were designed and tested in 2020 in dry climatic conditions using drained lysimeters and water balance methods. Four drainage lysimeters at the Agricultural Research Center were used for the experiment. Lysimeters of 50cm diameter and 120cm height were installed in the center of 25 × 20 m. Carla was planted in two lysimeters and in two lysimeters similar to the other reference plant (alfalfa). All planting operations were optimally performed and during the experiment it was tried to ensure that the soil moisture was not lower than the moisture content of the crop by timely irrigation so that the plant could not be subjected to moisture stress during the growing season. The experiment was conducted during a crop season from May 3 to July 27 for 88 days. Carla water requirement was determined between two consecutive irrigation intervals using soil water balance relationship. Carla water requirement was 915.15 mm during a experiment season. Also, the average coefficients of four stages of primary, developmental, intermediate and final growth in one experiment season were calculated 0.81, 0.915, 1.05, and 0.625, respectively.

New developed numerical models for solving hyperbolic Saint-Venant equations while having scientific and research value, play a significant role in the structural and performance management of hydraulic structures. In this paper, while developing two reverse explicit and semi-implicit numerical models based on Preissmann four points scheme, their application has been evaluated in a reach of Doab Samsami River, sub basin of Karoon. The reverse explicit has been developed based on Preissmann scheme and semi-implicit model has been developed using Preissmann scheme for distance derivatives with the Upwind scheme. Simulating of an output hydrograph using Manning roughness coefficient as setting parameter was performed with five accuracy criteria Nash-Sutcliff (NS), R-square (R2), Root mean square error and its standardized value (RMSE, NRMSE) and Developed discrepancy ratio (QDDR) for two calibration and verification periods. The amount of mentioned criteria for explicit and implicit models were calculated as (0.9352,0.9886,2.604,24.6,3.146) and (0.9843,0.9943,1.283,12.1,3.909) illustrating the reliable performance of the two models with the tangible superiority of the semi-implicit model. For more assurance of models performance, another hydrograph was simulated so that the values of NS, NRMSE and QDDR for semi-implicit and reverse explicit models were calculated (0.97,8.172,3.713) and (0.9339,12.28,2.612), respectively. These values proved the reliability and performance of the two models. The semi-implicit model had more accuracy than the explicit one in all cases. Solution stability in addition to high calculation efficiency is advantages of the semi-implicit model while leading to coupled complicated non-linear equations is its restriction.

Hydrological regimes play a major role in restructuring and operating ecological processes, wetlands and river ecosystems. Hydrological regimes of rivers flowing due to the construction of significant changes in the dam cause spatial and temporal heterogeneity of river systems and degradation of natural ecosystem services and threat to biodiversity. In this regard, effective management of the river ecosystem needs to describe the parameters of the hydrological regime of the natural flow and determine the degree of changes in the two statistical periods before dam construction and altered flow regime (after dam construction). In this study using IHA software, 33 hydrological parameters as indicators of hydrological change, in five statistical groups at Molasani and Ahvaz Hydrometric stations, to evaluate changes in Karun River downstream of Gotvand Dam from 1983 to 2018 in two periods Statistical normal flow regime and modified flow regime were used. According to the results, the hydrological indices at the Molasani and Ahvaz hydrometry stations changed significantly during the changed flow regime, so that the mean discharge values significant decrease in most months. Also, the percentage of hydrological change of 23 parameters in Molasani Hydrometry Station high, and 11 other parameters were low, and in Ahwaz Hydrometry Station, 24 parameter medium to high, and 12 other their changes were low. This indicates the high degree of hydrological changes in the Karun River Basin. The results of maximum daily, weekly, monthly and quarterly flows show that the construction of the dam has a negative effect on the Karun River discharge. The results of the study on the variability of the river variability approach also showed that the appropriate range of monthly discharge values at Molasani Hydrometric Station for the first six months of the water year, provided river life goals proportional to 2231.4 to 532.3 m3/s and for the second six months of the year this range was between 345.5 to 1235.4 m3/s, while at Ahvaz Hydrometric Station, for the first six months of the year, the appropriate range of monthly discharge ranges between 272.7 to 562.8 m3/s and for the second six months of the year this range was between 314.2 to 1255.6 m3/s. Finally, up to the annual values of each hydrological index of the river after the dam construction as far as possible in equilibrium with the flow domain reported inof the range of variability approach, in order to maintain optimal ecological conditions and integrity of the Karun River ecosystem water resources management (Regulatory role of Gotvand dam on flow regime).

Debris flow breaker protects the downstream against the risk of these flows by water drainage and energy dissipation. It seems that structure changing in such a way that it reduces the kinetic energy of the debris, increases the efficiency of the structure. In this research, based on the dimensional analysis, some experiments were carried out in other to improve the structure performance of the stony debris flow breaker in a flume with slope adjustment capability. In these experiments, the efficiency of the debris flow breaker was studied with different barriers by changing in size, shape and arrangement under the different conditions of debris flow. Jagged and multiple barriers are selected to stop debris on the structure. Based on the results of jagged barriers, the different placements were able to increase the efficiency of debris flow breaker by up to 25%. In addition, two or three-row barriers even with their low height, have increased the structure control efficiency by 10%. Based on these results, a new and optimized structure was introduced.

Baffled chutes are structures that are used to dissipate energy in chutes and water transmission and distribution structures. In the present study, baffled chutes were numerically studied using the Flow-3D numerical model. For this purpose, upon defining the boundary conditions, the validation was done using available experimental data and then, the effect of slope, chute length as well as the distance between baffles and their height on the energy dissipation rate of the baffled chutes was studied. The results showed that by increasing the distance between the baffle rows, the energy dissipation rate decreased. By increasing the height of the baffles using the design method proposed by the USBR, the energy dissipation rate slightly decreased. For similar slopes and other dimensions, by increasing the chute length by three times, the energy dissipation increased by 21.4%, and the energy dissipation rate decreased by increasing chute slope.

The use of spur dikes is one of the most common methods for controlling bank erosion and protecting river shores. In fact, the presence of the spur dikes causes the modification of hydraulic flow conditions as well as the reduction of water erosion power at the distance of two spur dike, that eventually causes the sedimentation and stabilization of the river banks. In this study, we investigated the effect of T-shaped spur dikes on erosion control by constructing a laboratory channel of meandering and using five spur dike. The experiments were conducted by taking three effective lengths three different froude numbers in impermeable and non-submerged conditions. The results of this study indicate that with the increase of the length of the spur dikes, the retreat rate has decreased. For the length of 9, 12 and 15 cm respectively, about 31.7, 35.4 and 58.0 percent of the mean retreat of the bank compared to the state without the spur dike decreased. In this study, three criteria R2, RMSE and MAE were used to compare the data obtained from the formula and the laboratory data, the amount of these indices were estimated 0.924, 0.127 and 0.097, respectively.

Restrictions on water resources in agriculture highlight the need for effective and efficient irrigation methods. On the other hand, deficit irrigation as a limiting factor to affects plant growth. In order to study the effects of regulated deficit irrigation and partial root zone drying on yield and yield components of greenhouse cucumber. an experiment was conducted in Jiroft. The experiment treatments were arranged as randomized complete block design with three replications. The irrigation regimes consisted of full irrigation. regulated deficit and partial root zone drying irrigation (RDI75. RDI55). The results showed that deficit irrigation resulted in water saving at the rates of 15.9-31.4 percent. The highest yield (257.6 ton/ha) was produced by full irrigation. There was no significant difference between yield of full irrigation treatment and 75 percent water replacement in partial root zone drying. The highest water use efficiency was 56.4 kg/m3 was obtained in 75 percent water replacement in partial root zone drying. Also. despite the same water consumption of 75 percent water replacement in partial root zone drying and regulated deficit. yield was decrease 13.4 percent. Therefore. it can be concluded that 75 percent water replacement in partial root zone drying. which resulted in a non-significant decrease of yield and while resulting in a 25 percent decrease in water use and increased 12.9 percent of water use efficiency. which can be considered as a superior treatment and a suitable strategy to cope with the water crisis and increasing irrigation efficiency in greenhouse cucumber cultivation in Jiroft area. to move towards a sustainable agricultural system.

Groundwater resources,as one of the most important resources of water supply, have been faced with the qualitative decline and increasing the concentration of pollutants in addition to a quantitive problems in recent years. According to the importance of the role of water supply quality in exploitation, recognizing the aquifer and factors affecting it is very important. This study was conducted to investigate the movement of pollutants with the view of assessing aquifer vulnerability in one of the branches of Zanjan River. Accordingly, two types of intrinsic and special vulnerability in the region were investigated by two methods of drastic and HPI. The results of vulnerability index show that the soil of region is effective in decreasing the concentration of heavy metals under study (lead, chromium, nickel, cobalt, zinc) and the concentration reduces in the direction of groundwater flow. The results of vulnerability index showed that the Drastic index is more than 80% in the medium to low and low ranking and the HPI index of the basin with an average of 30.3 is in the low risk, however, this basin has the potential to develop pollution. In order to determine the direction of pollution and the role of alluvial in the area MODPATH numerical model was used to simulate under the influence of the advection process in order to determine the direction of pollutants movement and the role of alluvium of the region. The numerical simulation of the region was carried out for three years after modeling and calibrating the MODFLOW model. Based on the results, the wells located along the groundwater and surface water flow path in the center of the basin have longer length compared to the wells that are around and far from the center of the basin. Based on the results, different patterns can be used such as creating barriers to modify and reduce the amount of pollutants transfer in this basin and other basins leading to Zanjan River.

Water conservation and increasing water use efficiency is one of the major principles of sustainable agriculture, especially in arid and semi-arid regions. Application of natural eco-friendly mulches is an effective method for reducing soil evaporation and consequently water consumption in agriculture. In this study, the effect of different mulch types on soil evaporation was investigated under saline and non-saline conditions. A factorial pot experiment in a completely randomized design was conducted with four mulch types (C1: bare soil, C2: gravel, C3: sesame residue and C4: pistachio residue), three levels of irrigation water salinity (S1: EC=0.8 dS m-1 (fresh water), S2: EC= 6 dS m-1 and S3: EC=12 dS m-1) in three replications. Results showed that the highest evaporation reduction after 3 weeks was observed in soil with gravelly mulch (58%) followed by sesame (41%) and pistachio (37%) residue as compared to the bare soil. Soil evaporation and residual water content in gravelly covered soil were respectively 7% lower and two times higher than those ones of the bare soil even 105 days after irrigation. Although the effect of water salinity on soil evaporation was not significant, however soil moisture in saline treatments was about 1-3% higher than that of non-saline one in any type of mulch. By generalizing the results of the evaporation reduction to the field, irrigation interval become at least 5 days longer and irrigation events of the pistachio orchards in Ardakan region decrease at least one time during the growing season. The amounts of reserved water due to application of gravel, sesame and pistachio mulch were 8.5, 6 and 5.4 Mm3, respectively. In view of the aquifer balance, these amounts of saving water results in 185 wells with 20 lit/s discharge being off for 27, 19 and 17 days, respectively.

Determining groundwater storage changes, especially in arid and semiarid areas, is a vital issue for groundwater management and planning. GRACE satellite produces changes in water storage with 1 degree spatial resolution using Earth's gravity field changes. In this study, it is tried to evaluate monthly groundwater storage changes between August 2002 and June 2016 in two pixels of one square degree of Khorasan Razavi province, which cover the whole area or parts of 6 aquifers using data from four GRACE satellite information processing centers named CENS, CSR, GFZ and JPL. Utilizing amount of Terrestrial Water Storage (TWS) obtained from GRACE satellite data, with data of soil moisture, snow water equivalent and canopy water storage derived from the GLDAS model which are presented with 1 degree spatial resolution on a monthly basis lead to estimates of monthly groundwater level changes. An estimation of monthly changes in groundwater level of the GLDAS model was obtained at a 25 degrees resolution in order to compare with the results of the GRACE satellite data. Observational data containing monthly groundwater level changes from the piezometric wells of the study area were used to validate the results. The results show that data of GRACE (CENS) with (RMSE = 14.35 and MAE = 12.645) are the weakest estimation of groundwater level changes. While the GRACE (JPL) data with RMSE = 5.708 and MAE = 5.038 shows the best estimation. It should be noted that the GLDAS model data with a resolution of 0.25 degree with an RMSE of 2.350 cm and a MAE of 1.826 cm shows a more appropriate estimate than the GRACE data types. GRACE data (CSR) showed the most favorable prediction of the trend of monthly changes in groundwater level by presenting a trend of -0.089 cm / month.

Today, using piano key weirs is a proper solution to increase the discharge capacity compared to existing weirs. The appropriate design of these weirs requires sufficient precision to predict the discharge capacity. In the current study, a new type of piano key weirs with a triangular nose has been used and to determine the effects of geometric parameters of the inlet to outlet key width ratio on the flow coefficient, various experiments have been carried on three-cycle weirs with a triangular nose under hydraulic conditions. The results of the study indicated that with the increase of hydraulic charge, the flow coefficient increases firstly and then decreases. The flow coefficient also shows an increase in Piano Key weir when the ratio of input key to output key increases from 0.8 to 1.25 and from 19.2 to 25.2%.A mathematical equation has been obtained using the results of the experiment to determine the discharge coefficient of three-cycle piano key weirs. This equation has less errors than other equations found in the previous findings. Furthermore, throughout the whole process of adhesion-aeration, piano key weirs reached the highest discharge coefficient (0.1 ≥Hd/P≤ 0.2) and two-cycle weirs gave a significantly higher discharge coefficient than three-cycle weirs. The results of this study revealed that the proportion of Wi/Wo=1.25 and the slope of 25.2 percent had the highest discharge coefficient (0.592).

Zarrineh Roud basin plays an important role in supplying water to Lake Urmia and the region's drinking and agricultural needs. Agricultural development, water transfer outside the basin and climate change have reduced the flow into Lake Urmia. In this study, we investigate the simultaneous impact of climate change and managers' s policies on the availability of water resources in the Zarrineh Roud basin. For this purpose, first using AOGCM model and SDSM downscaling model and considering two A2 and B2 emission scenarios, the minimum temperature, maximum and rainfall data for 2070 to 2084 are reduced and then basin's charge was calculated by using SWAT model. The results showed an average increased in water and temperature stress to 6/29 and 5/27 Centigrade degree and an average decrease in annual discharge into the lake under A2 and B2 emission scenarios. In the next step, a comprehensive dynamic system model of the zarrineh Roud basin was developed by taking into account the set of factors affecting it, and the impact of inland and out of case study basin on water resources was investigated after validation and calibration of model. The results indicate a conflict between the agricultural sector and the environmental need of Lake Urmia that increased production and agricultural levels would reduce the inflow into Lake Urmia.

In Iran, about 70% of agricultural crops are obtained through irrigation and the share of irrigation has been increasing since 1960. Given the growing trend in the world's population and to meet the water demand of other sectors, the share of water in the agricultural sector should be adjusted by improving water productivity. In Iran, the average water productivity is lower than that of the developed countries. In Ardebil plain, due to the decrease of groundwater resources and the decrease of rainfalls over the past 30 years, it is necessary to manage the water productivity and to reduce water consumption properly. The purpose of this study was to compare water productivity indices for major crops in Ardabil plain. In this study, the sample size was determined using Cochran's and Bartlett's et al. relationships, and the required information was collected by questionnaire. At first, 50 questionnaires were distributed among experts in agriculture. After assuring the validity and reliability of the questionnaire, 1046 questionnaires were distributed among the farmers in Ardabil plain. Results of water productivity (CPD index) showed that potato crop had the highest water productivity of 2.95 kg m-3 and rapeseed crop had the lowest water productivity of 0.67 kg m-3. Furthermore, potato (6093 Tomans) and barley (505 Tomans) had the highest and the lowest net profit per cubic meter of irrigation water, respectively. Based on the results, it is suggested that strategic crops such as wheat and rapeseed should be cultivated in order to reduce import level and facilitate the export mechanism for crops such as potatoes.

Bendway weirs are short-height structures that are completely submerged and are constructed to control the movement of bends, improve shipping conditions, create aquatic habitats, etc. The purpose of this study was to evaluate the pattern of erosion and sedimentation in a 90 degree bend with a relative radius of curvature 3.3 in the presence of Bendway weirs. To achieve this goal, a series of weirs with relative height 30 and 70% and crest slope of 0 and 7% were constructed on the outer wall of the bend. The angle (〖60〗^°), length (30% of channel width) and distance between weirs (3 times of weir length) were considered constant. The results show that due to the construction of weirs with relative height of 70% and flat crest slope, the maximum sedimentation (56.66% higher than the no-structure state) occurred at the maximum scour location. The maximum relative depth of scour in weirs with a relative height of 70% was about 17% higher than its value in weirs with a relative height of 30%. By increasing the crest slope for weirs with a relative height of 30%, the average maximum relative scour depth decreased by almost 27% in all hydraulic conditions around weir 5.

Monitoring long-term changes in water resources in each basin acts as a monitoring system. Investigating changes in water resources, how they are altered and their percentage in each basin will greatly contribute to the water resources management. In this study, after introducing water deficit signatures, we investigate the changes in these signatures using modified Mann-Kendall test with eliminate the effects of internal autocorrelation. In this study, the values of precipitation, discharge and groundwater levels deficiency were measured during 10, 30 and 60 days durations in 12 sub basins in Lake Urmia Basin. Rain gauge and hydrometric stations were used for precipitation and discharge values and the entropy theory was used to select the piezometer stations. The results of changes in deficiency signatures values showed that the overall changes are incremental, which in some cases is significant and in some cases not significant. In general, the results indicated that, on average, the rainfall deficit, discharge deficit and groundwater level deficit signatures increased by 52, 35, and 23 percent, respectively, over the long-term average. These changes for Lake Urmia Basin indicate an increase in meteorological, hydrological and groundwater droughts.

Plant water uptake under water stress conditions can be described quantitatively by some mathematical models. Water absorption models are useful tools for irrigation planning and optimal water management if they can provide accurate predictions of plant response to water stress. In general, two broad categories of water absorption modeling approaches, models are microscopic and macroscopic models Microscopic models of water flow to the single root and macroscopic models of water harvesting by the whole root area. The purpose of this study was to evaluate some macroscopic models under water stress conditions. For this purpose, experiment with three irrigation treatments I1, I2, I3, 100, 80, 60% water requirement, respectively, in a completely randomized design with three replications on summer maize cultivar (KSC-704) in Ahvaz climatic conditions in summer 2018. also treatments without cultivation were used to measure evaporation from the soil surface. To evaluate the models used (Fedes et al. 1978, van Genuchten 1987, Dierksen et al. 1993 and Homay 1999) from four statistical indices of coefficient of explanation (R2), root mean square error (RMSE), normalized error (NMSE) and mean relative error percentage (MRE) were used. The results showed that for I2 and I3 treatments, Van Genuchten (1987) model with statistical indices (R2 = 0.58, RMSE = 0.10), for I2 treatments, Van Genuchten& Co (1987) model with Statistical analysis (R2 = 0.35 and RMSE = 0.10) and for the I3 treatment, van Genuchten's (1987) model with R2 = 0.51 and RMSE = 0.10 compared to other models had the best fit with the measured data.

In order to optimal management of groundwater resources, accurate estimate of groundwater level fluctuations is required. In recent years, the use of artificial intelligence methods based on data mining theory has increasingly attracted researchers' attention. The purpose of the present study is to compare the performance of adaptive neuro-fuzzy inference system (ANFIS) and support vector machine (SVM) methods to simulate groundwater level fluctuations. A 22-year dataset (1996-2018) including hydrological parameters such as monthly precipitation (P) and groundwater level (GL) from 25 observation wells in some parts of Maragheh plain located in East Azarbaijan province were used as models input data. The average groundwater level in the study area is 1321 m and the annual precipitation and temperature was calculated 294 mm and 14 ◦C, respectively. Mean values of statistical indices of correlation coefficients and root mean square error were calculated 0.91 and 0.38 m for the ANFIS model and 0.92 and 0.40 m for the SVM model, respectively. Results showed that the addition of monthly precipitation parameter to the input data had no significant effect on the accuracy of the ANFIS model, however, the model prediction accuracy increased by 14% for the SVM model. In general, the simulation accuracy of both models was acceptable. However, it can be stated that the ANFIS model has a slight advantage over the SVM model.

Fuzzy methods in simulating water flow in to the soil has attracted the attention of researchers because of the possibility of considering the uncertainty and variability of the parameters in this methods. The sensitivity of the fuzzy model is to find the balance between the accuracy of the fuzzy model and its speed of execution, which depends on the number of fuzzy rules. Therefore, our goal in this research is to investigate the effect of the number of fuzzy rules on the accuracy of the model. In order to achieve this, the fuzzy model for predicting water movement in unsaturated soil was evaluated by considering fuzzy sets with different supports and consequently different rule numbers. The rules of the fuzzy model were derived from the large training sets obtained by numerical solution of Richards equation by using HYDRUS-1D model. The results showed that increasing the number of fuzzy rules initially increased the accuracy of the model (NRMSE value decreased from 4.3 to 3.1 and maximum error value from 0.128 to 0.09 for fuzzy model with 9 and 49 rules, respectively but by increasing the number of input fuzzy sets and increasing the rules to 81, the accuracy of the fuzzy model was reduced. The reason for the reduced efficiency of the fuzzy model is rules overlap.

Leaf area index (LAI) plays an important role in hydrological, agricultural, and land irrigation management studies. In order to adopt an appropriate, accurate, and robust algorithm to estimate the spatial-temporal distribution of LAI using Sentinel-2 images, the Support Vector Regression (SVR), Kernel Ridge Regression (KRR), Relevance Vector Machines (RVM), and Gaussian Process Regression (GPR) were calibrated and investigated. The research data were collected from silage maize farms in Ghaleh-Now county in Tehran province during the whole growing season in summer 2018 through destructive measurement and hemispherical photography. Our results were compared with the conventional algorithms in this field, i.e. random forest (RF) and artificial neural network (ANN). The results revealed that the GPR algorithm not only has higher accuracy (in 20-m band group, R2=0.913 and RMSE=0.641), speed, and robustness to estimate the LAI, but also it has the unique ability to generate uncertainty pixel-based map (uncertainty and relative uncertainty were less than 0.7 and 30% by 96% and 74% of the total area, respectively). Based on R2 and RMSE, SVR is the second accurate technique for LAI estimation followed by RVM, KRR, RF and ANN, respectively. Comparison of the estimated and field LAI at sampling times with RMSE=0.276 and bias=0.099 and other superiorities indicated the efficiency of GPR algorithm to estimate the spatial-temporal distribution of LAI.

According to the reduction of water level in many aquifers of Iran due to irregular extractions from these sources, implementation of the restoration and balancing plan for aquifer management is important particularly in arid and semi-arid regions. Artificial recharge by injection well is one of the management strategies available in this project that directly stores water in aquifers. The purpose of this study was to investigate the effect of injection wells on the unconfined aquifer of Birjand plain using MODFLOW-2000 numerical model in unsteady state conditions and based on injection of the annual runoff volume of the plain. In this regard, information about hydrodynamic characteristics of aquifer including hydraulic conductivity and specific yield, observation wells, extraction wells, aquifer surface recharge, top elevation of aquifer, bedrock and drainage was prepared then level of aquifer with The MODFLOW-2000 model was simulated in GMS 7.1 in steady state and saturated environment during 2010-2011. After simulation, the model was calibrated by manual calibration method and the results of steady state was entered as input of unsteady model and was validated in the 2011-2012 period. At the end, Artificial recharge management scenario was added to the model by injection well method with using 20 wells with discharge equal to 1909.61 m3/day for each well in one year. The validation results show the model's ability to simulate water level under unsteady conditions. Also, simulation of artificial recharge plan with injection wells showed that by applying this scenario, the level of water in all observation wells will increase on average 77 cm.

Considering the importance and special status, the critical conditions of water scarcity in production systems, and the lack of traceability of wheat water in Khuzestan, in this study, green, blue and gray water footprints of wheat product were estimated. The studied areas were Ahvaz, Dezful, Shooshtar, Behbahan, Izeh and Khorramshahr. The total water footprint of wheat was obtained from the sum of green, blue and grey water footprint. Then, the relationship between wheat water footprint and actual yield was compared. The results showed that among the study areas, Khorramshahr needed more water (1704 m3 t-1) to produce the product and thereafter, Ahvaz (1228 m3 t-1), Behbahan (1083 m3 t-1), Izeh (1012 m3 t-1), Dezful (959 m3 t-1) and Shushtar (915 m3 t-1). To produce 1 ton of wheat, Izeh needs 778 cubic meters of green water, and after that, Khorramshahr was ranked second with 458 cubic meters of green water. However, Izeh had the lowest blue water footprint, and the zoning of Khuzestan province in terms of the blue water footprint of wheat showed that the blue water footprint in the southern half of the province is more than the northern half. Grey water footprints also follow a similar blue-water trend. Whereas Shooshtar has the lowest water footprint with the highest yield, and Khorramshahr has the lowest wheat yield and the highest water footprint among the other studied cities.

Integrated water and land resource's strategies requires consideration of physical process in bio-physic model parallel to hydrological, agricultural, social and economic feedbacks in dynamics system. Coupling SD-based models of with physically- based models of environment is therefore a promising method for obtaining the best of both worlds to enable data exchange between different models which could cover the complex behavior caused by the various interactions. Therefore, in this study, in order to water resources allocation and performance estimation of Tajan irrigation and drainage scheme, VENSIM dynamics system model and WOFOST crop growth model were developed using scripting approach and PySD-PCSE coupling model. On this basis, the VENSIM and WOFOST models were first applied and calibrated in 2015, and were returned to Python according to coding instructions and the integration of the two models was performed. The results of the present study showed that the water resources balance was insufficient to supply agricultural demand, and from 155 million cubic meters, only approximately 81 million cubic meters were supplied that the deficiencies for fruits, citrus, rice, grain maize, cereal, oilseed and wheat are 52, 25, 30, 2, 1.2, 0.05, 1 and 1.52 MCM, respectively, which greatly impacts on crop yield. Also, according to the poor potential of water resources in the Tajan scheme, the calculated yield for crops such as corn, wheat and oilseeds is significantly different from the actual yield of crops. On the other hand, since the potential water resources of the Tajan irrigation and drainage scheme are insufficient to provide for agricultural demands, no supplies have been made for pulse in all areas and for oilseeds, wheat, corn and beans in some areas. Also, in order to estimate the best yield function of the coefficient of explanation of the different plotted graphs, the results of this comparison showed that all of these functions are of polynomial type and are consistent with the Dornbus-Kasam relation.

In this study, flow characteristics in 90 degree four-branch open channel junction with two inlets and two outlets simulated using FLOW 3D. Effect of parameters such as ratio of lateral to main inlet discharge, height of weirs on ratio of main outlet discharge to inlet discharge and water surface profile in junction were investigated and were compared with experimental results. Compression of experimental and numerical results showed good agreement, in simulation outlet discharge, so that RMSE and NRMSE in main outlet channel obtained 0.00047 m3/s and %3.357, in lateral outlet channel obtained 0.00488 m3/s and %4.834, respectively. For a constant discharge ratio, a decrease in height of outlet weirs, led to higher Froude number. Also comparison of experimental and numerical results for water surface profile showed good agreement, Too. In a constant height of weirs, when flow approaching the junction water surface profile decreased, and as crossing the junction, water surface profile showed increasing trendency, so that RMSE and NRMSE for water surface profile in main channel were obtained 0.036884 m and %15.75 and in lateral channel obtained 0.04891 m and 1.996%, respectively. An increase in inlet discharge ratio led to more water surface fluctuation in junction whereas height of weir decreased water surface fluctuations

Accurate simulation of scour hole’s geometric specifications, created due to flow jet collision to plunge pool bed, has a significant role in the design, construction and performance of weirs and energy dissipater structures. In this research, a comparative evaluation was done between experimental and numerical study of scour phenomena downstream of a siphon spillway using SVM algorithm with three sediment particles and three buckets angles for different magnitudes of flow discharge and tail water depths in a rectangular flume made from plexiglas. Three linear-independent dimensionless parameters were formed. Classic linear and non-linear regression model and FFBP and CFBP neural networks were applied more over the SVM algorithm to simulate the scour hole dimensions and were compared using five statistical indices as R, RMSE, MAE, N.S and DDR. A comparison of the quintuple accuracy indices showed that SVM algorithm had better performance than to the other models, especially classic regression ones. Among all parameters, SVM algorithm had acceptable prediction with higher and lower level of accuracy for "L" _"S" /"h" _"t" and "L" _"6" /"h" _"t" by quintuple above mentioned indices as (0.9954, 0.2056, 0.987,0.9851,7.855) and (0.8924,2.860,2.23,0.7587,1.405), respectively. Finally, a comparison was done among SVM algorithm and empirical predictors of scour hole depth. Comparison of accuracy indices showed that the SVM had a tangible and absolute advantage over empirical equations presented by other researchers.

As the rarest agricultural input, water has increased its productivity over the last few decades. Surveys based on the amount of virtual water and water productivity indicators in agricultural crops, we need to examine the relationships that indicate the actual amount of water consumption for crop production. The present study, virtual water content of selected crops (Wheat, Barley, Chickpea, Sugar beet, Potato, Tomato, Cucumber, Alfalfa and Clover) examined in Saqqez city of Kurdistan province using three indices of physical and economic productivity of water including CPD, BPD and NBPD in the year 2015-16. The results of CPD index for Sugar beet and chickpea products were 9.5 and 0.2 kg / m3 with the highest and lowest values, respectively. Also, the results of BPD, and NBPD for Potato and Tomato products were about 3900 and 395 Toman per cubic meter respectively, and the NBPD index of 1420 and -110 Toman per cubic meter had the highest and the lowest values respectively. Other results of the research on the amount of virtual water showed that the chickpea product with 4.2 m3 / kg virtual water had the highest level of virtual water, which is also the lowest virtual water productivity in this product. In contrast, the index for sugar beet at 10 kg / m3 has the highest amount of virtual water productivity in the study area

Advance data and infiltration parameters are used to evaluate surface irrigation. Philip infiltration equation is one of the most widely used equations in surface irrigation. For the first time, Shepard et al. (1993) presented a one-point method to determine the parameters of the Philip infiltration equation in surface irrigation. In recent years, a new two-point method has been proposed to determine the parameters of Philip infiltration equation. In the new method, the volume balance equation is not presented. As a result, the Shepard et al. (1993) volume balance equation is used to determine the advance phase (Ebrahimian-Sheppard method). In this study, the volume balance equation for the new two-point method is presented. The volume balance equation presented in this study was evaluated with five independent furrow irrigation data sets and different input conditions. Results showed that mean value of root mean square error in Shepard et al. (1993), Ebrahimian-Shepard (2010) method and new two points were 40.5, 30.3 and 10.9, respectively. The absolute mean error of prediction had the lowest equilibrium of 9.6% in the new two-point method followed by the Ebrahimian-Sheppard (2010) and Sheppard et al. (1993) methods with 19.5 and 20.4%, respectively. The coefficient of determination for all three methods was more than 0.97. In general, it can be concluded that the method presented in this study predicts the advance curve with higher accuracy compared to the other two methods.

Desalination is one of the ways to cope with water scarcity in agriculture sector, especially in areas with saline water. The condensation irrigation as a method for irrigating with saline water and solar energy, is a combination of subsurface irrigation and simple solar distillation. In this study, a condensation irrigation with area of two square meters was developed in a greenhouse, in order to study the feasibility for meeting plant water requirement, so a humidifier with dimensions of 170×70×15 cm was made in which saline water was evaporated using a heating element. The vapor humidified the air above the salty water surface and warmed it. The air was blown into 5 two-meter-long perforated pipes buried with 20 cm intervals at deep of 8 cm. The water vapor then condensed inside the pipe wall and soil, providing the required water for the basil plants grown in the soil. The results showed that daily average of humidifier insertion into the perforated pipes was 12550 ml of water, of which 4167 ml were converted into liquid water in the soil and tubes. Also, this system with average daily irrigation of more than two millimeters was able to meet basil water requirement and production of wet and dry matter in this system was 32% and 63% more than control pots.

The purpose of this study was to evaluate the application of SARIMA time series statistical model in different climatic samples of Iran in order to forecast meteorological drought. To this end, the standardized precipitation index (SPI) was used on a 12-month scale. Precipitation data were used over a 20-year period (2000–2019) at 7 synoptic meteorological stations of Iran located in climatic samples classified from extra-arid to per-humid. The SARIMA time series model was developed after checking the stationary and seasonality of precipitation data in the MiniTab software. Akaike and Bayesian Information Criteria (AIC & BIC) were used to identify the optimal model. The results showed that due to the periodic and seasonal trend of precipitation, the use of SARIMA model is appropriate in all the studied stations. The precipitation residuals in the study stations were very close to normal and the model performance was satisfactory in forecasting precipitation and consequently drought. It is also expected that in the extra-arid moderate climates, arid and semi-arid (very cold and cold) climates, Mediterranean moderate climates, humid cold climates, and per-humid types A and B climates, the probability of severe drought, moderate drought, near-normal and moderately wet will occur, respectively.

Impact of frequent wetting and drying cycles process on soil mechanical parameters is important issue that should be considered in selecting the borrow area of fine-grained soil in many structures such as earth dams’ core, irrigation canal bed soil and road subbase. In this study, the effects of sequential wetting and drying cycles on physical and mechanical properties of clay soil is investigated. The uniaxial shear, triaxial shear, direct shear, swelling potential, hydraulic conductivity, and pressure plates tests were conducted on clay samples during wetting and drying cycles. The results showed that the wetting and drying cycles resulted in significant changes in the physical and mechanical properties of the soils and the compressive strength of the samples decreased by 32% after six wetting and drying cycles. The results of direct and triaxial shear tests also showed that application of 6 wetting and drying cycles reduced soil cohesion by about 40% but had no significant effect on the internal friction angle of the soil. Hydraulic conductivity tests showed that soil permeability increased about 19 times after wetting and drying. The pressure plates test, which shows the relationship between moisture content and suction in unsaturated soils (SWCC), revealed that as the number of cycles increased, the soil-water characteristic curve shifted downward and soil water retention capacity decreased.