Iranian Journal of Irrigation and Drainage
Year:2020 | Volume:14 | Issue:4|Papers Count:30

Drought is one of the natural and recurring climatic phenomena that has various effects on economic, social and environmental sectors. Drought, itself, is not a challenge, but it is the beginning of a crisis depending on the degree of vulnerability and impact it has on various sectors. Therefore, this study has attempted to calculate the risk of drought for the baseline period using natural risk definition and to estimate the best model for predicting its rate for future periods affected by different methods under climate change. Accordingly, drought risk was calculated using the two meteorological drought indices SPEI and eRDI the for years 1983-2015. Then, was determined the degree of vulnerability for the Afin area using a questionnaire. After estimating the risk during this time period, with the help of the Markov chain statistical technique, the drought risk characteristics of the region were obtained. Using the four modeling methods the best drought risk prediction model was determined and by using the meteorological variables studied from the three climate models of the CORDEX project the drought risk for the years 2020-2100was predicted. The results of this study showed a decrease in risk for 2020-2046 and an increase in 2047-2000 based on both RCP4. 5 and RCP8. 5 compared to the period 1983-1995.

Despite the high capability of field-scale agro-hydrological models to simulate plant growth interactions with water and solute transport in agricultural systems, their application to real conditions of large sugarcane fields in Khuzestan province faces many challenges, including spatial heterogeneity of irrigation scheduling across the field, the difficulty of determining initial and boundary conditions as well as several unknown model parameters, and data–, intensiveness of calibration procedure. This work aimed to implement the agro-hydrological modeling under real operational conditions of large fields with surface/subsurface drainage. In this work, a distributed agro-hydrological modeling scheme was developed through the application of a modified version of the SWAP model and an improved variant of the Unified Particle Swarm Optimization (UPSO) algorithm with capability of sub-daily calibration and simulation of controlled drainage. The developed model was applied to a sugarcane field with subsurface drainage with planted sugarcane (CP48-103 cultivar) in Imam Khomeini Sugarcane Agroindustrial company farms, during 2010-07-19 to 2011-12-11 (481 days). The results revealed the reasonable performance of the developed modeling scheme in retrieving the measured soil moisture, groundwater level, subsurface drainage outflow (with an EF of 0. 901, 0. 827, and 0. 877 for calibration dataset,and 0. 514, 0. 798, and 0. 672 for validation dataset, respectively), soil water solute concentration, subsurface drainage outflow salinity (with a NRMSE of 0. 039 and 0. 096 for calibration dataset,and 0. 154 and 0. 046 for validation dataset, respectively), Leaf Area Index, cane yield, and sucrose yield (with an EF of 0. 995, 0. 999, and 0. 972, respectively).

Forecasting of river discharge is an important aspect of efficient water resources planning and management. In this study, time series pre and post-processing methods along with support vector machine (SVM) and Gaussian process regression (GPR) kernel based approaches were used to estimate flow discharge of two natural river in the United States with two consecutive hydrometric stations. The first river contained about 2 years of data and in the second river 4 years of daily discharge data was used. Different models were defined based on hydraulic characteristics and the capability of integrated pre and post-processing methods in two states of interstation and between-stations was investigated. For data pre-processing, the Discrete Wavelet Transform (DWT) method was first used. Then, the high-frequency sub-series were selected and re-decomposed using the Ensemble Empirical Mode Decomposition (EEMD). Finally, sub-series with higher energy were imposed as inputs for kernel-based models. Non-linear neural average (NNA) model was also used for data post-processing. The obtained results from the defined models showed the high accuracy of the integrated methods used in the research in estimating flow discharge. At both stations, the error percentage was reduced by approximately 20 to 25% using the integrated pre-post-processing methods compared to the intelligent kernel based models. It was observed that in the case of river flow prediction based on the station's own data, the RMSE error value of the model decreased from approximately 0. 3 to 0. 26 and in the case of using the previous station data decreased from 0. 44 to 0. 33. Due to the high capability and accuracy of the pre-processing methods used in this study, similar studies are recommended in other rivers of the country.

The analysis of steady-state flow within rockfill materials is performed using two methods of gradually varied flow theory that analyzes the flow as one-dimensional and the Parkin equation that analyzes the flow as two-dimensional. The calculation of the hydraulic gradient (i) is of great importance in both methods. Most of the research in this area has been done in homogeneous rockfill materials and limited studies have been carried out on the flow in heterogeneous rockfill materials. In this study, we used the results of experiments in homogeneous and horizontal heterogeneous rockfill materials with three layers of aggregates with large, medium and small size. In the experimental data used in the present study, changes in hydraulic gradient relative to the flow velocity in each of the three homogeneous layers were available separately and also the changes in the horizontal heterogeneous media consisting of three layers were available separately. Due to the fact that in order to form a horizontal heterogeneous rockfill media, large, medium, and small homogeneous layers are placed on top of each other, respectively, in the approach presented in the present study, the data of the steady flow of homogeneous media are placed in the same order in the Particle Swarm Optimization (PSO) algorithm to optimize the coefficients of the binomial equation (a, b) and consequently the calculation of hydraulic gradient. In other words, in the present study, the values of the coefficients a, b, equivalent to the horizontal heterogeneous media, depending on how the homogeneous layers are placed on top of each other and only using the data of steady flow in the homogeneous media (large, medium and small size) Optimized. The results show that the difference of mean relative error (MRE) the approach presented in the present study than conditions where flow data in a horizontal heterogeneous media are directly used to calculate the coefficients a and b and consequently the hydraulic gradient, is 1. 38 percent.

The development of intelligent irrigation systems with the aim of providing the plant with water in a timely and adequate manner is an important strategy to increase the quantity and quality of agricultural products with minimal water consumption. On the other hand, determining the amount of water required by the plant largely depends on an accurate estimate of evapotranspiration in vegetation. In this study, neural network model was used to estimate the evapotranspiration in a lettuce hydroponic rotary culture system. The actual evapotranspiration of lettuce in the hydroponic cultivation system was estimated in order to design the irrigation system with the help of fuzzy logic model. Cultivation time was 30 days and data sampling time from temperature and humidity sensor was 10 minutes. According to the desired results obtained from the evaluation of the planted crop and water consumption, the efficiency of fuzzy model was proved. Therefore, it was used as a criterion for validating the neural network model of this study. The data volume for the neural network model was about 4500, which was randomly divided into three parts, 70% (training), 15% (evaluation) and 15% (test). Different ANN structures were evaluated to find the most suitable neural network architecture. The best result was achieved with BR algorithm with three hidden layers in an 8-10-10 topology and tansig transfer function in three hidden layers and output layer. For this architecture, the absolute error and coefficient of determination were 0. 43 and 99. 98%, respectively. Furthermore, considering a simple single layer network (one hidden layer), the BR algorithm with 8 neurons and logsig and tansig transfer functions for the hidden and output layers, were selected as the best model. The error and coefficient of determination of this structure were 0. 79 and 98. 84%, respectively. According to the sensitivity analysis, humidity and temperature were the most important parameters in predicting evapotranspiration, respectively.

In this paper, the issue of energy losses in Gabion Stepped Spillway and the effect of grain size on stone materials on it have been investigated. Laboratory models of the L r= 1/5 scale overflows for steps 2 and 3 were 40 and 60 cm high, respectively. The stone materials were prepared as round stones from borrowed sources based on the scale model with dimensions of 4, 6 and 8 cm, equivalent to the normal size of the stones used in gabion structures. The models were installed in a 50 cm wide hydraulic flow with a discharge capacity of up to 65 liters per second. The results show that energy losses in rocks with a diameter of 4 cm are higher than in other cases. Also, by increasing the number of steps from 2 to 3 steps in Gabion Weirs, the efficiency of Energy losses increases. In all cases, the efficiency of energy losses in these overflows decreases with increasing flow rate. Construction of gabion stairwells up to 3 steps will increase the efficiency of energy losses in the laboratory environment and consequently in nature.

Groundwater is an important water resource especially in arid and semi-arid regions. Therefore, according to the conditions, it is necessary to study and predict the qualitative changes of water in the future. In this study two quality parameters Including electrical conductivity (EC) and sodium adsorption ratio (SAR) taken from 18 groundwater wells in Chaharmahal and Bakhtiari Province during the years 1991 to 2016 were used. First, the primary zoning map was drawn from the parameters at the beginning and the end of the data range, then the suitable model for each parameter in each well was choiced and by drawing a map of groundwater quality zoning in 2021, the changes between these years was studied and groundwater quality was determined by Wilcox. Based on the results, selected ARIMA models have good performance. Also, according to these models, the average amount of predicted SAR (absorption rate) in all wells will decrease in 2021 compared to 2016, while the average amount of EC (electrical conductivity) is increasing in all wells. Therefore, according to the reviewed qualitative parameters, the majority of the region can be classified in the C2S1 and C3S1 classes, that will be salt and harmful water for agriculture.

Given the potential of modern irrigation system, it is important to perform intelligently irrigation, or in other words, determine the time, place and amount of water in order to maximize water use efficiency in the face of water shortages. This study was conducted to examine the effect of different levels of soil suction threshold before irrigation and crop rotation on yield and water use efficiency of maize in loam soil under drip-tape irrigation system. The three irrigation management levels contain,irrigation based on ETC calculation using FAO-PM equation (W1), soil moistures suction levels of 40 kPa (W2), and 20 kPa (W3), and two crop rotation contains,fallow-maize (Nfal) and wheat-maize sequence (Nseq). Total biomass, and leaf area index during the growing season and grain yield at maturity stage were measured. The maximum total biomass, grain yield, and leaf area index were observed in NfalW3 treatment with 25 ton/ha, 12. 6 ton/ha, and 5. 3 m2/m2, respectively. The difference between water use efficiency and irrigation water use efficiency was lowest in the third level of irrigation management, indicating a precise irrigation based on the water requirement of the plant and reducing evaporation and penetration losses.

Considering the current and prospect situation of Urmia Lake, the future study of variables of irrigation scheduling and management is one of the priorities of agricultural research to improve the cropping pattern in the east of lake. In this study, the time series of wheat evapotranspiration in sixteen regions of East Azarbaijan located at the east of Urmia Lake was determined using the Penman-Monteith FAO method with the regional crop coefficient. The analysis period was 80 years from 1330-31 to 1396-97, which 50 years (from1330-31 to 1379-80) was applied for the time series modeling, 17 years ( from 1380-81 to 1396-97) for testing and 13 years (from 1397-98 to 1409-1410) for future studying up to 1410. Among the eighteen possible models, the appropriate time series model for wheat evapotranspiration in cold climate regions such as Azarshahr, Osko, Bonab, Tabriz, Jolfa, Maragheh, Malekan, Marand and Miyaneh was acquired as ARIMA (0, 1, 1) and for very cold climates such as Ahar, Bostanabad, Sarab, Shabestar, Kaleibar, Harris and Hashtrood was obtained as an exponential trend model. The wheat evapotranspiration in East Azerbaijan in the past 67 years averaged 478 mm and for the next 13 years averaged 500 mm. The findings of this study are valuable and practical for irrigation scheduling in full and deficit irrigated conditions and reduction of drought damage in east Urmia Lake.

In order to investigate the effects of irrigation water and Nitrogen fertilizer on the quantity and quality charactristics of potatoes under drip irrigation, a two-year field experiment was conducted in Agricultural and Natural Resources Research Center of Semnan province (Shahrood). The experiment was conducted based on split plots in a randomized complete block design with three factors and four replications. The design factors were: 1-water rates (75 and 100 percent of requirement water) 2-rates and methods application of nitrogen (60, 80 and 100 percent requirement nitrogen with fertigation method and 100 percent requirement nitrogen with traditional method) 3-planting arrangement (35 and 45 cm), and a control treatment. The experiment was performed using a split factorial plot design (planning arrangement as main plots and water-nitrogen rates as sub plots). The amount of requirement water irrigation was determined by penman-mantith method and metrological data in tape irrigation method, also requirement nitrogen fertilizer was used by fertigation method until to before of flowering duration. Irrigation period was used 3-day. The results showed that the effect of irrigation water on the nitrate concentration of the tubers was significant. Nitrogen concentration in the irrigation water levels 75% and 100% were 310 and 287 ppm respectively. Also, the results showed that there was a significant difference between nitrogen concentrations in fertilizer treatments. The accumulation of nitrate concentration in the fertilizer treatments of 100, 80 and 60 (in drip irrigation method) was 339, 312, and 258, respectively. And in the fertilizer treatment 100% with a traditional method was 289 ppm. The effect of water treatments on water use efficiency have significant. The water use efficiency were obtained at 75 and 100 requirement water 3. 05 and 2. 82 respectively. The 80% Nitrogen fertilizer (fertigation), 75% irrigation water and 45 cm planting distance as the best treatment was selected.

Finding optimal pipe diameters in water supply networks for minimizing design costs due to the constraints and high decision variables is one of the major challenges for designers. In the last few decades, the development and introduction of new optimization methods, the good performance of these methods in solving complex engineering problems has led engineers to develop these methods in the design of water networks. In the present study, the performance of one of the emerging metaheuristic algorithms called Ant Lion Optimizer (ALO) in solving the problem of optimizing the diameters of water supply networks was considered. For this purpose, a multi-objective optimization-simulation model based on the ALO and the EPANET simulator model was developed. The developed model was used to optimize the diameter of Ismail Abad network pipes. The results were presented as a Pareto front between the design cost and the sum of the pressure difference squares. The results showed that using this model in addition to saving design costs about 15% compared to the existing design conditions,it has been significantly successful in reducing overload pressure in the nodes. As a result, this method can be used with confidence as an efficient method in designing water supply networks.

Drought is one of the meteorological and inseparable phenomena of climate in countries located in tropical latitudes such as Iran. In this study, drought monitoring data from MODIS sensors were used to extract VCI and TCI indices in plant growth months (March to August) from 2001 to 2017. The objective is to evaluate the satellite drought monitoring in the Greater Karun Basin using SPI index. After calculating the satellite indices in ENVI software, the values were compared with the SPI index calculated in MATLAB and zoned by IDW interpolation method. Finally, in all indicators, the southern part of the catchment showed severe drought. High correlation of VCI index was also shown by examining correlation between satellite indices and SPI index. The highest correlation coefficient of this index was for Azna and Yasuj stations with 0. 62 and 0. 59, respectively.

An experiment was conducted with greenhouse tomato plants to determine the effects of oxygen enrichment of the irrigation water on yield and yield components. The study was conducted based on randomized complete blocks as a split plot design with 4 replicates and 3 treatments for 2 years. It is possible to simultaneously irrigate and provide roots with sufficient oxygen via injection of ambient air by means of a venturi coupled to a subsurface drip irrigation system (SDI) called as oxygation. In this study, three levels of irrigation water aeration comprising 0 (the Control), 12 and 24 volumetric percent (i. e. air volume/water volume) was applied to tomato plants grown on a saline clay soil and saline water in a greenhouse in Esfahan Agricultural Research Centre. The type and amount of the required fertilizers were determined from the analysis of soil samples. Tomato plant growth was promoted under conditions which facilitated consistently high oxygen in the root zone. The differences between the aeration treatments and the zero aeration control were significant at the 5% level only for the fruit diameter, fruit length, the number of fruit and total fruits weight. There were no significant effects (P > 0. 05) between control and aeration levels for height plant, root dry mater and plant dry mater. The results also showed that the values of yield and water productivity in the treatment of 24% oxygenation compared to the control treatment increased by 21. 7% and 21. 5%, respectively. Data from this study indicate that tomato production in saline soils and saline water can be improved under SDI if the subsurface drip irrigation is aerated.

A good understanding of the river natural flow regime plays an important role in many hydrological studies Such studies also quantify the environmental flow, the basis for the conservation of river fish habitats and aquatic ecosystems, and need to be recognized in the policies and decisions of water resource development plans and their inclusion in watershed management plans. In the present study were calculated and evaluated hydrological methods such as Tennant, Aquatic Base Flow, Arkansas and Range of Variability Approach (RVA) to estimate the minimum ecological flow and Habitat Simulation model to preserve the ecological potential of the Jajroud River. In this regard, based on the research framework, after hydrological analysis and field observations, a habitat suitability model was developed for the target species and finally, habitat simulation was performed by combining ecohydraulic and hydrological indices of flow and analysis of flow-habitat physics time series using suitability curves. Based on the results, to maintain optimal conditions and protect the ecosystem components and habitat of biological communities, using the River2D model range of flow regime required to provide habitat ecological potential Squalius namak, it should be located along the Jajroud River between 1. 24 to 18. 55 m3/s, with mean annual flow 5. 91 m3/s (86. 7 Percent Mean Annual Flow). It is noteworthy that the Tennant methods should be used with caution in summer because this method offers between 9 and 96 percent of the mean annual flow. Finally, it was concluded that other methods of providing environmental flow provide values above 25% of the mean annual flow, which provide better protection of the stream for aquatic habitats. In contrast, the River2D ecohydraulic model can provide a general idea of habitat suitability across different river basins with respect to changes in natural flow regimes and the achievement of ideal and optimal flow conditions.

Irrigation management plays an important role in the performance and productivity of rice water consumption. This experiment was conducted to investigate the effect of irrigation time on yield and of Ratoon Hashemi cultivar in the form of a factorial design with three replications and in three crop years at the Rice Research Institute (Rasht). Irrigation treatment was at three levels of permanent flooding (I1), capillary cracking (2 mm) (I2) and coarse cracking (5 mm) (I3). The results of compound analysis of variance showed that all quantitative and qualitative traits of rice ratooning were significantly affected by the test years. In general, due to the right temperature and hours of sunshine, ratoon growth conditions in the first year of the experiment were better than in the other two years, which positively affected plant height, cluster length and 1000 grain weight, increasing grain yield by 1122 kg/ha. The effect of irrigation management on ratoon yield and yield components also showed that coarse crack irrigation increased yield by 463. 4 kg/ha compared to other treatments. Also, the highest plant height of 104. 8 cm was obtained from flood irrigation. Irrigation management was not effective on other traits such as 1000-grain weight, straw yield, and cluster length and harvest index. The highest water productivity in the first year was 0. 69 kg/m3/ha and the lowest in the third year was 0. 41 kg/m3/ha. Also coarse crack irrigation treatment compared to permanent flood irrigation treatment increased water productivity by 65%.

Crop Models are useful tools for simulation of crops to environmental factors. In order to use crop model, it is necessary to evaluate their accuracies and efficiencies. So, the study was conducted to evaluate the accuracy and efficiency of AquaCrop and SWAP models for simulation of sugar beet under different irrigation intervals. Irrigation in four intervals (I1: 6, I2: 9, I3: 12 and I4: 15 days) during three continues year (Y1: first years, Y2: second year and Y3: third year) at Feiz Abad research station in Qazvin were studied. First year data was used for calibration and second and third year data were used for validation of both models. Results showed that both AqauCrop and SWAP had underestimate error for simulation of yield and water productivity. AquaCrop model (RMSE=1. 79 ton. ha-1) had better accuracy compared to SWAP (RMSE=1. 85 ton. ha-1) for simulation of yield. According to NRMSE, accuracy of both models was the same and classified in very good group. Efficiencies of both models (EF=0. 99 and d=0. 99) were acceptable. Regarding the results, it is proposed to use both models for simulation of sugar beet yield and water use efficiency.

The presence of nitrate in water resources is one of the most important global concerns, so it can be very helpful to prevent it from entering the water using materials such as hydrocar, biochar, zeolites and superabsorbents. For this purpose, this study with four treatments at 3 different levels and 4 repetitions was conducted in 2019. In this study, 36 PVC pipes with diameter and height of 10. 5 and 50 cm, respectively, were used at research farm Faculty of Water Sciencs Engineering, Shahid Chamran University of Ahvaz. Treatments included hydrocar (H), biochar (B), potassium zeolite (Z), and superabsorbents of type A200 (S) at three levels (M0, M2, and M5, respectively, including zero, 2, and 5 g / kg soil), respectively. The duration of the experiment included 10 irrigations, and at the end of each irrigation, the output nitrate was measured. The results showed that the effect of superabsorbent, zeolite and biochar in all irrigations and hydrocar other than irrigation 4 and 6 at 5% level was significant on reducing nitrate leaching. SM2 and SM5 treatments were 42% and 58%, respectively, ZM2 and ZM5 treatments were 20% and 29%, respectively, BM2 and BM5 treatments were 30% and 43%, respectively, and HM2 and HM5 treatments were 20% and 31%, respectively, compared to control treatment was effective in preventing nitrate leaching. In general, superabsorbent treatment is recommended due to higher absorption.

Excessive extraction of aquifers to produce agricultural products is reduced the amount of water in groundwater sources, in the manner that this amount decreasing follows irreversible effects in various areas. In order to decreasing difficulties resulting from decrease in amount of aquifer deciding in considerable level is needed. This matter has made balancing of aquifers as one of the important factors in water resources management. In this study, in order to recovery of groundwater sources and implementing extraction reduction in country's aquifers, as one of the equilibrium projects, optimization the cultivation pattern with economical approach and investigation changes farmer's profit with exploitation reduction scenarios to 1%, 3% and 5% From two popular perspectives and analytical comparisons between them is done in 1395. For optimize the cropping pattern, two perspectives of changing the cropping pattern have been used by NLP method and reduction of cultivated subspecies, and using PMP optimization method. Results of using extraction reduction scenarios in Qazvin plain's aquifer, which has yearly deficiency to the value of 376 MCM showed that in the scenarios of groundwater extraction, the values of 21. 2, 63. 7 & 106. 6 MCM of extraction are reduced from the aquifer of the case study. Also, the results of the analysis of the two planning methods showed that the NLP optimization model, gaining more economical profits than the PMP model.

Estimation of runoff from atmospheric rainfall has a special importance in hydrology studies, watershed management and soil science water conservation. In order to efficiently manage the watershed, the need to investigate the efficiency of hydrological models is more effective. The software package RRL is designed to simulate the runoff relationships of the basin and consists of five sub-conceptual models. In this study, conceptual models of AWBM, SACRAMENTO, SIMHYD, SMAR and TANK were used for Silakhor plain watershed (Rahim Abad station). The daily data of precipitation, evaporation and discharge were used in the statistical period of 1998 to 2018. For all conceptual models, from 1998 to 2000, as a balance period, from 2001 to 2013 as calibration and from 2014 to 2018, it was selected as the verification period. In the SIMHYD model, the Nash-Sutcliffe coefficient in the Multi Pattern Search Start method in the calibration and validation stages were 0. 70 and 0. 68, respectively, which indicates the relative ability of this model to simulate runoff among other models. In the TANK model, calibration and validation using Genetic Algorithm, the Nash-Sutcliffe coefficient were 0. 47 and 0. 44, respectively, which had the lowest efficiency among the models. The results showed that in the different optimization methods, the Multi Pattern Search Start method provides better results.

In this study, an Analytical program has been conducted to identify the behavior of of amplitude aquifer to different water turbulence and find a relationship for optimal groundwater abstraction of this aquifer. The geographic information system is first used to process geological, hydrological, and hydrogeological data, and then the MODFLOW-2000 code is used to simulate the flow. After the initial simulation, the hydraulic conductivity parameter in a stabilized steady situation (April 2005) and in a unstable situation (2004-2005) The hydraulic conductivity parameter and the discharge coefficient, in particular, were measured. Then, for a period of 18 months, with the data of 2012-2013 and for the optimized parameters, the validation test was performed. Two different management scenarios for a 102-month period were defined to predict groundwater level fluctuations and the effect of water pumping from the domain aquifer. The results of the numerical model analysis show that if the aquifer is operate with the current situation, the sharp drop in water in the aquifer and the gradual drying of the aquifer will continue in the future, so that the maximum and minimum drop limit of observation wells number 5 und 3 is respectively 12/20 meters and 1. 70 meters. Of course, lowering the discharge pumping rate will improve this situation. Therefore, considering that the range amplifier is fully developed, the power supply-pumping diagram was drawn. The results show that by using the nutrition-pumping diagram, the water level can be controlled to a certain extent by considering economic and environmental issues and the areas of aquifer that are close to the aquifer (trava boundaries) are affected and the wells operating in this area have the least effect on the drop in water level.

Evapotranspiration (ET) is one of the essential components of the hydrological cycle, which plays a crucial role in the study of a watershed water balance. In calculating the water requirement of plants, it is essential to calculate the reference evapotranspiration, and then, the crop evapotranspiration is estimated using the calculated value. In the present research, for accurate determining of daily reference evapotranspiration of Lake Urmia watershed, three stations of the watershed, including Urmia, Mahabad, and Khoy, were selected and daily reference evapotranspiration values were calculated based on the standard FAO-Penman-Monteith method. The best input parameters for modeling reference evapotranspiration were selected based on Malo’, s coefficient. The MT model, which is used in the current study, is one of the inference-classification algorithms. To deal with the complexity and instability of time series data, the empirical mode decomposition (EMD) preprocessing algorithm was used. The results of the methods were compared with the empirical relationships of Romanenko and Schendel. The results of this study show that although the tree modeling method performs relatively equal and sometimes weaker than the ANN method, the combination with EMD technique increases the accuracy of the model and reduces the error in daily ET0 prediction. According to the results, the EMD-MT method in correlation coefficient index for Urmia, Mahabad, and Khoy stations increased 1. 02%, 4. 39%, and 2. 04%, respectively. Also, among the empirical relations, the Romanenko relation is more accurate than the Schendel equation, and it is a reliable empirical model.

Water scarcity is a prominent feature of arid and semi-arid regions that jeopardize agricultural production. Therefore, efficient management and use of water resources in agricultural production is essential. One way to manage and increase water use efficiency (WUE) in agriculture is to determine the amount of water used in the production process of agricultural crops, which is used to calculate the amount of water consumed in crop growth stages from the virtual water index. Therefore, the purpose of this study is to calculate the water use efficiency (WUE) of agricultural products in the Khash region under the virtual water and water footprint approach. Therefore, the water requirement was first obtained using the CROPWAT model. Then, the volume of virtual water, green water footprint, and blue water were calculated using Data Envelopment Analysis (DEA) to calculate water use efficiency. The results showed that 20. 15% of the total water requirement of Khash agricultural crops is provided by green water and 79. 85% by water. The virtual water content of crop production in this region is 853 m3/ton and the water footprint shows the total amount of water harvested for agricultural production is 133. 554 million m3. The DEA results show that the average water use efficiency of crops in the Khash region is 70. 8%. Corn, potato, onion, tomato, eggplant, melon and watermelon, alfalfa, forage corn, and sorghum with efficiency score 1 Component of efficient crops and dates, grapes, wheat, rice, and barley were among the inefficient products. Using the Fair Ranking Method (FRM) we found that the least efficiency was related to dates and the highest to sorghum product. Finally, it was found that products with a higher water footprint had a lower water use efficiency.

The Piano key weirs are new types of weirs which have a high discharge capacity and are more economical and highly efficient. in the current study, to determine the effects of geometrical parameters of ratio of input key on discharge coefficient, 180 experiments have been done on two-cycle and three-cycle weirs under different hydraulic conditions. The results of the study indicated that by increasing hydraulic load, at first discharge coefficient increases and then it decreases. Discharge coefficient in the piano key weir also increases to 26% by increasing ratio of input key to output key from 0. 8 to 1. 25. the analysis of number of cycles revealed that the maximum rate of discharge coefficient for two-cycle weir was between 0. 6 and 0. 76 and for three-cycle weir was between 0. 4 and 0. 59. throuout the whole process, the performance of two-cycle weir was much better than threecycle weir since the discharge coefficient of it was 29%. the reasons for this are the complexity of discharge conditions in three-cycle weir, more streamlines interference, local immersion, more energy loss and the increasing number of cycles in a specified width with the same effective length. The optimum condition of Atype piano key weir in terms of the simultaneous effect of weir slope and ratio of input width to its output using triangular nose has been examined. The analysis of findings showed that a piano key weir with a ratio of key width of 1. 25 and a slope of 25. 2% with a triangular nose is the best combination for the maximum rate of discharge coefficient.

Quadratic weir is one of the unique types of available thin plate weirs that can be used for flow measuring in water transmission channels, irrigation networks and urban runoff networks because of its unique capabilities. In this research with the aim of investigation the effect of side contraction ratio on discharge coefficient of this weir, the flow through a quadratic proportional (chimney) weir in a rectangular channel with 10 bed widths and with side openness ratios of 10 to 100 percent, is simulated in 3D by ANSYS FLUENT software and has been calibrated using similar laboratory results. After measuring of water depth at the upstream channel for different passing discharges in each channel widths, The average of discharge coefficient in range of water depth between two and three times the height of triangle basin was calculated and results showed that in side openness ratio between 10 and 30%, the discharge coefficient value was 0. 6 with no change, but with the increase in the crosssectional openness ratio from 30% to 100%, the discharge coefficient increased and its final value in the 100% openness was 0. 65. Finally an experimental relationship was proposed to correct the discharge coefficient based on the side openness ratio.

Water as a vital resource is one of the most important factors for growth and development in human societies. Mashhad plain is one of the critical plains of Iran that the drought of the past years has caused the level of aquifers to drop. This study aims to investigate the factors affecting water demand in the Mashhad plain. Necessary statistics and information for this purpose were collected by the Ministry of Jihad for Agriculture and the Meteorological Department of Khorasan Razavi Province for the dominant crops in the region's cultivation pattern, including wheat, barley, tomatoes, alfalfa, cucumbers and potatoes. In order to determine the amount of water required by the products, the net water demand index, which is a function of evaporation, humidity, rainfall and wind speed, and NETWAT software were used. The factors affecting the net water requirement of these products were investigated using the Sur panel pattern. The net estimated need for the model was used as the amount of water demand. The spatial panel pattern was used to investigate the factors affecting this index. The meaningful of the Neighborhood Variable (Rho) indicates that the pattern under study is spatial and that the use of classical patterns is difficult. The results of the data analysis show that as the price of water, the cost of irrigation, the cost of chemical fertilizers and the cost of renting land increase, the amount of demand for irrigation water decreases and the excessive consumption of water is prevented.

In order to determine the best irrigation method to improvegrowth and physiological traits of some promising peanut (Arachis hypogea L. ) lines in Guilan province, two experiments carried out in 2017-2018 cropping seasons as split plot based on randomized complete block design with three replications in Rasht, Iran. Two irrigation methods including of cretaceous (conventional) and furrow (ridge) methods and five promising peanut lines ( 128, 176, 192, 201 and 208) comprised experimental treatments as main and sub plots, respectively. Results showed that cretaceous irrigation methodcaused to increase pod numbers per plant (26. 46). In this experiment, peanut 192 line produced the greatest seed yield (3128 kg/ha), seed unmber per pod (2. 08) and biological yield (8983 kg/ha) in response to cretaceous irrigation method. In addition, the greatest seed oil content (52. 94 %) was obtained under conventional cretaceous irrigation method. In general, results showed that the cretaceous (conventional) irrigation method ofpeanut enhanced seed numbers per pod, seed yield and biological yield of peanut promising lines under region climatic condition.

The high rate of evaporation from water surfaces, especially in hot and dry areas, is one of the most important challenges which the water resources managers are facing with. Jiroft is one of these areas where the evaporation rate reaches five to six times the global average. This region is one of the most important agricultural hubs in the country and has a large number of water storage pools for agricultural purposes, which a large volume of water are wasted annually due to the evaporation induced by high sunlight, high temperatures, long hours of sunshine and relatively strong winds. In the present study, the effect of two types of artificial (granular polystyrene) and natural (Cordia myxa leaves) cover on the intensity of evaporation from the water surfaces of this region (study location: Jiroft University’, s research farm) in the hottest days of the year (May 15 Until June 15). The effect of each of these covers on the five densities of 10, 25, 50, 75 and 100% and three replications was investigated and the results were compared with the reference (without cover) test. The results of comparing the means and statistical analysis with the least significant difference (LSD) test showed that both types of covers in all densities had a significant effect on the reduction of evaporation. Comparison of the daily evaporation rate of covered treatments compared to reference test showed that artificial covers performed better than the natural covers in reducing the evaporation. The results of monthly evaporation showed that artificial and natural covers at 100% density, reduced evaporation by 29% and 24%, respectively, compared to the reference test.

Having a pervasive knowledge about the groundwater balance conducts the engineers and managers to have an optimal management about these resources. In the present study, with using meshless local Petrov-Galerkin, one of the meshless methods in the field of fluid dynamic, groundwater balance is computed for a real field aquifer. The independency of this method from meshing the domain, removes the drawbacks and errors come from meshing state and improves the accuracy of results. The case study is Birjand unconfined aquifer located in South Khorasan province, east of Iran. After groundwater flow simulation and model calibration in one year 2011-2012 with monthly time step, the groundwater head is computed for each month and compared with the results of finite difference method (FDM). RMSE, MAE and ME criterion are calculated for both methods. They are 0. 757m, 0. 573m,-0. 08m for MLPG method and 1. 197m, 1. 434m, 0. 159m for FDM, respectively. The higher results of MLPG shows more correspondence of this method to real condition of aquifer. Finally, the input and output volume of water are computed for the aquifer. They are almost 91 and 88 MCM respectively. Therefore, the value of groundwater balance is computed. It was 3 MCM with minus sign which indicated the higher amount of output regarding to inputs.

This research was conducted as a split plot experiment based on completely randomized design with three replications at natural resources and agricultural research center of Kashmar. Irrigation treatments including full irrigation (i. e. providing 100% irrigation water requirement of plant), 80, 60 and 40% irrigation water requirement were as main plots and plant density treatments including density of 10, 20 and 30 plants per square meter were as sub-main plots. The results showed that irrigation treatments and plant density were significant on some traits such as plant height, 1000-grain weight, grain yield and water productivity (WP) at one level percentage (P<0. 01). Interaction of irrigation treatments and density was only significant on biologic yield and panicle no. per plant. The highest grain yield and WP with quantities of 3395 Kg/ha and 0. 87 Kg/m3 respectively, was observed for full irrigation treatment and density of 10 plants per square meter. In all of the irrigation treatments by increasing the plant density, the biologic yield decreased significantly. There was no significant difference among the harvest index in all of the deficit irrigation treatments. Considering the effect of drought stress and increasing of plant density was significant in grain yield and WP reduction, it is recommended that full irrigation method and density of 10 plants per square meter was applied for planting of grain millet in Kashmar region.

Due to the ambiguous dimensions of clay pipe sub-surface irrigation in different soil texture a two-year study was conducted aimed to investigate the effect of two water qualities with electrical conductivity of 0. 87 and 3. 78 dS/m on emission of clay pipes respectively, under laboratory and field conditions with three types of clay loam, sandy loam and loamy texture at two meters hydrostatic pressure. The laboratory results of emission measurements resulted in a multivariate model for predicting long-term final pipe emission. Also, water salinity significantly changed the parameters of the equation, hence confirming the effect of salinity on pipe emission reduced. The significant point in this study is the significant reduction in initial emission in saline water use compared to low salinity water. On the other hand, a mathematical regression relationship was found with high correlation for total water volume. The study of emission of clay pipes in laboratory and field showed the susceptibility of these pipes to reduced emission even in low salinity water use, even showed that the amount of pipes in the long run will be significantly reduced, which should be replaced according to the salinity of water, irrigation and soil type.