مجله آبیاری و زهکشی ایران
سال شانزدهم شماره 2 (خرداد و تیر 1401)

The FAO Penman-Monteith (FAO-56 PM) model is proposed as a standard model to estimate reference evapotranspiration (ETO) in various climates. Different models are used to estimate the total solar radiation (Rs) as one of the essential inputs of this model. This study aimed to calibrate and validate four Rs estimation models (Ångström-Prescott, Hargreaves-Samani, Mubiru et al., and Chen and Li) in Ahvaz (with arid climate) and Hamedan (with semi-arid climate) stations during the 1992-2020 climate period and the effect of these models on the ETO estimation. The coefficients of these models were calibrated by the intelligent shuffled frog leaping algorithm (SFLA). To evaluate the efficiency of these models, the estimated Rs values were compared with measured values. Based on the root mean square error (RMSE), the coefficient of determination (R2) statistics and Nash-Sutcliffe, the A-P model with RMSE=1.929, R2=0.918, NS=0.896 and Mobiro et al. model with RMSE=2.925, R2=0.875, NS=0.860 showed better performance than the other models in Ahvaz and Hamedan stations, respectively. A decrease of about 20% was observed in the percentage of ETO difference between, the calculated and the estimated Rs compared to the measured Rs in 2 stations at all of the models.

In recent decades, several factors such as population growth, limited surface water resources due to reduced rainfall, and over-withdrawal of aquifers have caused a sharp drop in groundwater levels (GWLs) in many plains of Iran, including Salmas plain located in the province of West Azerbaijan. In this study, the numerical model of the Salmas plain aquifer was prepared using MODFLOW model in GMS software in both states of steady flow (September 2015) and non-steady flow (from September 2016 to August 2017). The input parameters of the model were calibrated for the measured values of GWL at the location of observation wells and validated from August 2016 to July 2018. Finally, the GWL was investigated applying 6 scenarios including a 10% to 30% decrease in pumping wells and a 5% to 15% increase in rainfall. The results of studied scenarios showed that reducing the pumping rate of the wells significantly improves the condition of groundwater resources. By reducing the pumping rate of the wells up to 30%, the volume of groundwater will increase by 13.66 mcm and shortage of the aquifer reservoir will be compensated. However, 15% increase in annual rainfall will improve the condition of the aquifer by only 0.5 mcm. Results show that reducing the rate of withdrawal from wells reduced the amount of groundwater flow entering the aquifer from 41.98 mcm in the calibration state of the model to 38.7 mcm in terms of 30% reduction of discharge rate in the wells. However, the increase in rainfall did not cause significant changes in the amount of groundwater inflow and outflow. The results of this study indicate that management scenarios such as preventing over-withdrawal from authorized wells and blocking unauthorized wells have more significant effects on improving the GWL than possible climatic scenarios.

Changing rainfall patterns and increasing population in Mazandaran province has caused the correct use of surface water resources in various sectors, especially agriculture is inevitable. Despite appropriate rainfall potential in Mazandaran province, there is no regular plan for the management of surface resources. While using the ab bandan, some of the problems of the water sector in this area can be solved. To evaluate this issue in the present study, the SWAT model was used in the Tajan watershed from 2000 to 2017. First, the efficiency of the model and its results were evaluated as the current situation, then the scenario was implemented without considering the ab bandans. The SUFI2 algorithm in SWAT CUP software was used to analyze the uncertainty, calibration and validation of monthly discharge and sediment at six selected stations. The performance of the model was evaluated by coefficient of determination and Nash Sutcliffe. R2 coefficient in runoff and sediment simulation was obtained in the range of 0.68_ 0.87 and 0.62 _ 0.79, respectively. Also, the NS coefficient for runoff was in the range of 0.52 _ 0.72 and sediment was in the range of 0.58 _ 0.74. The results showed that the model had a satisfactory performance in simulating discharge and sediment. The findings of the scenario show that in the absence of ab bandans, runoff discharge and sediment output will increase by 16.3% and 17.5%, which indicates the inhibition of discharge and sediment by these structures. Also, by examining this scenario, during the floods, these structures had an effective role in flood control by inhibiting 17% of runoff and 27% of sediment. Due to the capacity of ab bandans in controlling discharge and sediment, it can be planned to manage surface water resources control floods by increasing the surface area and volume of these structures.

Water shortage is one of the main problems of Hamedan province. Meanwhile, the agricultural sector is more vulnerable than other economic sectors due to its high share in water consumption. Therefore, appropriate and efficient use of this limited resource is essential. The aim of this study was to determine the productivity and economic value of water in the agricultural sector and the revenue-generating potential of this resource in the production of two major crops of wheat and barley. For this purpose, farms in Hamadan province were selected by random sampling and were studied. The required information was prepared through field measurements, completing a questionnaire and interviewing farmers. The economic value of water was calculated using the final analysis method and the Cobb–Douglas production function. The average water productivity of wheat with two sprinkler and surface irrigation systems was determined as 1.24 and 1.03, respectively, and in barley as 1.55 and 1.02 kg / m3. Wheat and barley production elasticity was estimated to be 0.139 and 0.283, respectively. these amounts indicated that if water consumption increases by an average of one percent, the average wheat and barley production will increase 0.139 and 0.283, percent respectively. The economic value of water for two crops of wheat and barley was estimated at 2043 and 3755 Rials per cubic meter, respectively. Considering the cost of 496 Rials, water extraction from underground sources, it can be said that the economic value of water in the two crops studied is much higher than the costs incurred by farmers for its extraction. Therefore, by determining the economic value of water and receiving water prices, incentives can be directed towards more efficient water allocation and increased productivity.

Labyrinth weirs are considered as an appropriate choice to correct the weirs that are having difficulty in passing the maximum possible flow. For this purpose, in the present study, a new weir was introduced called the of pseudo-Cosine labyrinth weir. First, models with different widths and heights were built in FLUENT software as a virtual laboratory. The anti-corona algorithm and adaptive neuro-fuzzy inference system (ACVO-ANFIS) were used for predicting discharge coefficient. of pseudo-Cosine labyrinth weir. Validation of the proposed method was performed using Experimental data. Then, to identify the superior model and determine the parameters affecting the discharge coefficient of pseudo-cosine labyrinth weir, the combination of different dimensionless parameters was evaluated. The performance of the proposed method was evaluated with five statistics, including determination coefficient (R2), root means squared error (RMSE), mean absolute percentage error (MAPE), nash-sutcliffe (NSE), and relative root mean square error (RRMSE). The results showed that in low hydraulic heads, the discharge coefficient has its highest value. As the radius increases, the discharge coefficient increases due to the increase in the effective length of the labyrinths. At a constant H/W, with increasing weir height, the discharge coefficient increased. The results of the ACVO-ANFIS model showed that the input variables are the ratio of the radius to the weir height (R/W), the ratio of the length of the weir to weir height (L/W), and the ratio of the hydraulic head to the weir height (H/W), with error values R2=0.971, RMSE=00.9, MAPE=0.006, RRMSE=0.010, and NSE=0.977, the most effective parameters in determining the discharge coefficient of pseudo-cosine labyrinth weirs.

Optimization of cropping pattern can be the best approach to reduce water consumption with maintaining maintain or increasing agricultural productions and consequently increase farmers' incomes. In this research, the cropping pattern of Mahabad irrigation and drainage network (with an approximation area of 12,000 ha) was determined using the PSO optimization algorithm with the objective of increasing the net benefit of the network based on the specified amount of delivered water and increasing water productivity. Optimization was done in 6 treatments of full and deficient irrigation and two strategies of deficient irrigation implementation (H1: in delivered water to the network and farm and H2: in delivered water to the network). Finally, the amount of water consumption, net benefit and economic productivity in the optimal cropping pattern were compared with the present condition. The results showed that in H1 strategy, with water consumption equal to the present condition, the amount of net benefit and economic productivity in the optimum cropping pattern increased about 16.7% compared to the current situation. In H2 strategy, productivity increased compared to the present situation in all treatments. Even by a reduction of about 40% of delivered water to the network, economic productivity increased about 37% compared to the present condition.

Water balance is one of the most important issues that should be paid special attention in the discussion of water resources management and as a result of decisions and plans for water consumption in different sectors. In this paper, using remote sensing products, the conceptual model of Thomas water balance (abcd) in a basin with semi-arid climatic conditions was calculated and evaluated. First, the monthly output of IMERG satellites and the re-analysed temperature of ERA5 were compared with ground-based measurements. Evaluation results of these products using five statistical indicators including Pearson correlation coefficient (R), root mean square error (RMSE), mean absolute error (MAE), Nash-Sutcliffe efficiency coefficient (NS) and deviation coefficient (BIAS) in the Zarandeh sub-basin located in Neishabour region shows their high accuracy and correlation with observations. Then, using these products and GIS, the conceptual model of Thomas for this sub-basin was developed in MATLAB software and its performance in basin runoff simulation was investigated. Fuzzy numbers and the Monte Carlo method were also used to reduce uncertainties in model parameters. This model was optimized with two different objective functions of Nash-Sutcliffe efficiency coefficient and determination coefficient. The results show the high accuracy of the abcd water balance model using remote sensing products in the study area and well simulation of the discharge behavior.

Corn is one of the most important grain crops in the world. Corn yield and production is highly dependent on water and nitrogen availability. In this study, the calibrated AquaCrop model, using data collected from a research study in Seed and Plant Improvement Institute, Iran, was used to determine the appropriate irrigation amount and nitrogen fertilizer level under field conditions during 2008-2010. In addition, irrigation-yield, fertilizer-yield and irrigation-fertilizer-yield production functions were determined in order to quantify the results. Hence, yield and water use efficiency of corn were simulated by the AquaCrop model under different irrigation amounts (at levels of 30 to 120% of water requirement) and nitrogen fertilizer treatments (at four levels of 100, 80, 60 and zero percent of fertilizer requirement). The results showed that by providing 80% of the total crop irrigation requirement, acceptable amount of yield and water use efficiency will be achieved. However, crop yield and water use efficiency were improved by increasing fertilizer application rate. Results demonstrated that, corn grain yield in W3 treatment was equal to 11, 10.8 and 10.2 ton ha-3 under 100, 80 and 60% fertilizer treatments, respectively. Also, the obtained Water use efficiency of these treatments was equal to 1.45, 1.53 and 1.36 kg m-3, respectively. In addition, a simple form of production functions for both irrigation-yield and fertilizer-yield simulation models were recommended. However, for irrigation-fertilizer-yield production function, the quadratic form was the best suited model among others.

Although direct measurement of Silage maize yield is accurate but is difficult, time-consuming, costly despite, and not applicable in large scale. Due to these limitations, the tendency to use indirect methods has increased such as remote sensing in estimating crop yield. However, accurate estimation of crop yield through remote sensing always faces challenges such as the use of images and image parameters suitable for each region. The aim of this study was to increase the accuracy of estimating the fresh weight of Silage maize before the harvest by using Monteith Model (1972) and remote sensing. The parameters of the Monteith model were optimized such as the energy efficiency coefficient absorbed in the area, and the biomass of Silage maize was estimated using Landsat 8 satellite data and compared with the biomass measured in the field. The estimated yield with the optimized model showed a significant correlation (R2 = 0.85) with the actual yield of the fields. The results showed that the estimation error was reduced to an acceptable level (± 10%) by optimizing the parameters with the Monteith model compared with the none-optimization of the parameters. The corn dry weight estimated by the optimized model was converted to fresh weight yield and then by using the NDVI values of satellite images, after the highest NDVI value, a linear relationship with an acceptable correlation coefficient (R2= 0.81) for fresh weight estimation of fodder corn was presented in during the growing period in the study area. Overall, the yield of Silage maize can be predicted with acceptable accuracy by using NDVI results with one or two pre-harvest images (1-3 weeks before harvest) and using the obtained relationship.

Due to the vulnerable nature of earthen dams , all factors affecting the stability of these dams should be studied. Consecutive wetting and drying of the earthen dam core is one of the important factors that can affect the physical and mechanical parameters of the dam core. These changes increase the subsequent risks such as leakage, piping and subsidence. This is especially happen in arid and semi-arid regions such as Iran. Various researches have been done in this field and some of these researches have provided suitable mathematical models for their data, but because the results of each research related to the studied soil are specific to the same study, these models can be unusable for other data. In the present study, after collecting 866 laboratory data from 23 researches, the effect of wetting and successive drying of clay dam cores on physical-mechanical parameters was investigated and multivariate mathematical relationships between physical-mechanical parameters and number of wetting and drying were investigated. This study showed that the effect of wetting and drying on mechanical parameters is very important and should be considered in the analysis of embankment dam structures.

Dam construction is one of the most common development programs for the use of water resources, which is considered one of the most challenging topics in water resources management due to changes in the hydrological cycle. In this study, by modeling the Neyshabur aquifer using GMS software, the effects of conjunctive use of surface water and groundwater resources for drinking water supply in Neyshabur city (water intake of dam and exploitation wells) have been evaluated in different parts of the aquifer. The results show that based on the water balance prepared for the four periods of dam intake (from 2014 to 2017) and the mathematical model of the aquifer, the intensification of groundwater level drop occurred up to 1.35m in the Neyshabur aquifer. Moreover, in the case of transferring water for drinking in Neyshabur city and reducing the exploitation of drinking water wells ,reduction of drop intensity between 1.1 and 2.66 m will be observed for two scenarios, namely water transfer based on water intake and approved allocation. In addition, the intensification of groundwater level rise in the urban area will be realized by 0.25 and 0.93 m for the two mentioned scenarios, respectively. The results of research reveald, Bar dam construction has significant impact on water table fluctuations in parts of aquifer and range of impact can be well assessed and predicted by modeling.

This study was conducted to investigate the response of salicornia persica, directly irrigated with Persian Gulf saline water in Bushehr region, to reducing its required water and to determine the relationships between applied water and dry matter. The experiment was performed in a randomized complete block design with 3 replications. The treatments included T1, T2, T3, T4, T5 and T6, with total applied water of 6700, 8800, 9600, 10000, 11800 and 14700 m3.ha-1, respectively. The results showed that the applied water has important role in the dry matter; So that in the treatments of T1 to T5 with a significant difference it applied water, no significant increase was obtained for the crop yield. The average dry matter of the treatments was relatively constant and about 3000 kg.ha-1. However, increasing the volume of applied water in T6 treatment had a positive and significant effect on dry matter and increased it to 4600 kg.ha-1. Under the mentioned field conditions, Salicornia water productivity (WP) was obtained between 0.15 to 0.44 kg.m-3. Therefore, to achieve yields of 5 tons per hectare and more, a timely and sufficient water supply system (by shortening of the irrigation cycles) will be required for the Salicornia fields. The latter conclusion confirms the positive response of Salicornia to the increase of applied water, which can well illustrate the challenge of water supply importance in Salicornia fields.

The objective of distribution and delivery of water canal scheduling in irrigation canal networks is timely and adequate delivery of water with minimum operational stages of the head gate of supply canal in the presence of canal capacity and irrigation rotation period constraints. Poor performance of irrigation canals and its effect on decreasing of Agricultural water productivity requires attention for their improvement. Traditional approach for water delivery planning is based on personal experiences, which is not necessarily Satisfactory. The use of analytical and optimization methods could resolve some of these difficulties. Classical optimization methods are facing some limitations such as: being trapped in local optimum points, and difficulties in handling different variables. To overcome some of these limitations, new techniques which can solve complex problems could be used. This study has used the meta-optimization algorithm of PSO optimization to distribute and deliver optimal water in the irrigation network of Nesa Dam in Bam city located in Kerman province. In this research the delivery and distribution program in distribution channel branches are provided so that the various objects such as decreasing in distributor channel capacity and decreasing in time needed for complete the irrigation program optimize as a single and two objectives. In this program, first branch numbers, upper and lower limit of delivery discharge to per branch and branch coverage, gross irrigation requirement, irrigation interval and block numbers as input are defined to the model. By running the model, the best intermittent of branches in per block, minimum of distributer channel capacity and minimum irrigation duration in optimum conditions define to the model as outputs. According to the results presented the maximum flow rate is 2469 lit/s and the maximum irrigation time is 356 hours, which is reduced by 531 lit/s and 4 hours of irrigation time.

The combined behavior of the overflow flow from the overflow with the outlet jet under the valve creates different conditions downstream of such structures and causes scouring downstream of these structures. To solve this problem, the overflow and the valve can be combined. And formed a centralized hydraulic system called a weir-gate, which allowed the transfer of sediment from under the valve and floating material from the spill. The geometry of the present research model in FLOW-3D software was created in a rectangular channel with a sedimentary and erodible bed state and in a non-lateral compression state. Bed materials, non-stick sand and fluid used were considered as clear water and zero channel slope. In this study, two turbulence models (LES) and model (RNG) and 3 equations of bed load transfer rate were used and after validation with laboratory data, it was observed that the numerical model data with Van Rijn relation And with LES turbulence model with coefficient of determination R2 = 0.985 and mean absolute error RMSE = 0.107 has a good fit with laboratory data. The presented results indicate that with increasing upstream depth, the maximum scour depth increases Find. Also, by increasing the height of the overflow structure in a fixed opening of the valve, the maximum scour depth increases due to the jet falling, and with increasing the opening of the valve, the height of water on the structure decreases and also the outlet jet decreases and causes Reduce scour depth. Also, with increasing the flow rate over the overflow and under the valve and the upstream water level, the maximum scouring depth increases.

The purpose of this study is to evaluate the agriculture sustainability and determine the cultivation pattern in the Caspian temperate climate by the implementation of water consumption reduction policies (price, quota and a combination of the two) based on five scenarios of economic, environmental, social, and equal and experts' opinion preferences. The required information including documentary and field data from the production cost questionnaire and face-to-face interviews with farmers were obtained in the 2019-2020 crop year. The questionnaire and interviews with experts were used to calculate the weights of sustainability criteria and sub-criteria. In order to achieve the goals of the study, Positive Mathematical Programming method and Analytic Hierarchy Process were used. Based on the average opinion of experts used in this study, economic, social and environmental weights criteria in sustainability were calculated to be 0.453, 0.232 and 0.315, respectively. Also, the cultivation pattern will change based on the implementation of water consumption reduction policies. According to the economic and environmental sub-criteria, a 30% water quota policy and according to the social sub-criteria, a 50% price increase policy will lead to agriculture sustainability and optimal water consumption at the same time. In addition, to improve the pattern of water consumption in the agricultural sector, in the city of Turkmen as a representative of the Caspian temperate climate, a policy to reduce the volume of water use by 30% is proposed by applying policies (price, quotas and a combination of the two) in all preferential scenarios except the social preference. In the social preference scenario, a 50% increase in the water price is proposed. In the other words, there is an opposition between economic and environmental sustainability and social sustainability when implementing water consumption reduction policies And there must be an exchange between them..