Original Article
Irrigation network management
omolbani mohammadrezapour; meysam salarijazi
Abstract
Extended Abstract
Introduction
In the design of underground drainage systems, the depth, diameter and distance of the drains are important decision making variables. Depending on the type of target, different combinations of them can be used. In the usual drainage designs, the design variables ...
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Extended Abstract
Introduction
In the design of underground drainage systems, the depth, diameter and distance of the drains are important decision making variables. Depending on the type of target, different combinations of them can be used. In the usual drainage designs, the design variables of the depth and diameter of the drain are determined by using experience and the conditions and facilities of material preparation, and the distance of the drains, after determining the drainage coefficient and water balance, is determined by using the Hooghoudt equation. Since design variables are intrinsically interdependent, methods can be used to determine the best combination of variables that leads to minimum implementation costs. The aim of this research is to optimize the design parameters of underground drainage systems with an economic approach. Optimization is finding the best solution in order to minimize or maximize one or more objectives by observing the constraints of the problem. The present study was conducted based on the current economic situation and observations of the country and on the basis of the actual executive figures of Iran in 2018. In this research, genetic and multiverse algorithm optimization model was used to optimize the main design parameters of the underground drainage system of regional agricultural lands around Gorgan city.
Methodology
In this research, Genetic and multiverse algorithm optimization model was used to optimize the main design parameters of the underground drainage system of regional agricultural lands around Gorgan city. The area of the construction area of the drainage system was around 200 hectares. These areas were divided into 25 plots of 8 hectares and project costs were calculated for each. Using genetic and multi-world algorithm, the design parameters were selected in such a way as to lead to the lowest implementation cost of the underground drainage system. In this regard, the design parameters were selected by combining Hooghoudt equation and optimization algorithms.
Results and Discussion
By applying the genetic algorithm optimization model to the data of the studied lands, the optimal parameters were calculated. Considering the entire search area (permissible depth of drainage installation from 1.5 to 3.5 meters from the ground surface), the results showed that, by entering the drainage coefficients of 1.5, 2, 2.5, 3, 3.5, 4 and 4.5 mm per day the lowest cost of 49.9 million Tomans was obtained in 8 hectares with a drainage coefficient of 4 mm per day, at a depth of 3.13 meters from the ground surface with an installation distance of 79.8 meters and a diameter of 100 mm. Also, the optimal parameters were calculated by applying the multiverse algorithm optimization model. The results obtained from Aliabad land input data showed that by entering the drainage coefficients of 1.5, 2, 2.5, 3, 3.5, 4 and 4.5 mm per day, the lowest cost is equivalent to 49.8 million tomans in an 8-hectare unit with a drainage coefficient of 4 mm per day was obtained at a depth of 3.13 meters from the ground surface with an installation distance of 80 meters and a diameter of 125 mm.
The best design parameters using the genetic algorithm according to the implementation criteria of the drains including diameter, the distance of the drains, the optimal depth and also the costs for an 8-hectare plot including 100 mm, 54 m, 2.11 m and 70.604 million Tomans have been obtained. In the multiverse algorithm, these values are 100 mm, 61.3 meters, 2.25 meters and 63.709 million Tomans, respectively. Also, the cost of the project decreases with the increase of the allowed depth of the drain installation, the lowest and highest costs obtained in the genetic algorithm for the maximum allowed installation depth of 1.75 and 3.5 meters are equal to 110.226 and 51.814 million Tomans, respectively. In the multi-world algorithm, it was obtained as 110.223 and 51.782 million tomans, respectively.
Conclusions
In this research, the optimization model of genetic and multiverse algorithm for lands around Gorgan city was used. The construction area of the drainage system was about 200 hectares. These areas were divided into small plots of 8 hectares and the design costs for that small unit were calculated. Therefore, 25 units of 8 hectares have been considered for the study area. In this study, using genetic and multi-verse algorithms, these parameters were selected in such a way as to lead to the lowest operating costs of the underground drainage system. Results showed the best design parameters using the genetic algorithm according to the implementation criteria of the drains including diameter, the distance of the drains, the optimal depth and also the costs for an 8-hectare plot including 100 mm, 54 m, 2.11 m and 70.604 million Tomans have been obtained. In the multiverse algorithm, these values are 100 mm, 61.3 meters, 2.25 meters and 63.709 million Tomans, respectively.
Acknowledgement
The responsible author of the article is grateful to the Jihad Keshavarzi Organization of Gorgan, this research was carried out with the financial support of this organization.
Original Article
Irrigation network management
Mostafa Aslani; Mohammad Javad Monem; Ali Bagheri
Abstract
Extended Abstract
Introduction
Education and Extension factors, both in improving the productivity of water resources and in observing the approved cultivation pattern by farmers, are among the factors that affect many performance indicators of irrigation networks. The effect of this training should ...
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Extended Abstract
Introduction
Education and Extension factors, both in improving the productivity of water resources and in observing the approved cultivation pattern by farmers, are among the factors that affect many performance indicators of irrigation networks. The effect of this training should be systematically investigated in the chain of water, food, and energy Nexus in irrigation networks.
Methodology
The trainings were analyzed in the developed Nexus conceptual model in the borders of the Qazvin irrigation network using a system dynamic approach. The presented quantitative model in this section includes eight subsystems, two of which are directly affected by training factors. The two considered subsystems are "Agricultural Development Limitation" and "Solutions for Solving Unsatisfied Water Needs". The Nexus index was defined as a linear combination of some indices including water efficiency, energy efficiency, Production Utility, and water delivery adequacy.
Results and Discussion
In this research, taking into account the incremental changes in the number of hours of extension training, in three options of 20, 40, and 60%, the number of changes in the indicators of network adequacy and agricultural water productivity, and finally the nexus index were investigated.
The amount of effectiveness improvement in the three options of 20, 40, and 60% was 0.35, 0.34, and 0.32 percent respectively, and the effectiveness rate for the three options was 0.072, 0.087, and 0.104 respectively. This means that increasing the amount of training, even to the smallest amount, can have a great effect on improving the performance of the network in terms of improving water consumption and observing the cultivation pattern in line with water demand management. Considering the effectiveness of the options, it can be claimed that with the maximum increase in education, we can expect more effective changes in the above-mentioned fields.
Conclusions
It can be claimed that one of the most important factors under agricultural services, whether to observe the cultivation pattern or to improve water consumption, is extension training. According to the results, it can point out the importance of the effect of training parameters along with other technical parameters on the performance of irrigation networks and the security of water food, and energy resources in the Nexus chain.
Original Article
Irrigation network management
Seyed Hasan Tabatabaii; Seyed Majid Mirlatifi; Hosein Dehghanisanij; Ashkan Shokri
Abstract
Extended Abstract
Abstract
The impact of the application of data assimilation (DA) on improving the accuracy of estimates of ET was investigated by applying two different methods of (DA) namely Ensemble Kalman Filter (EnKF) and Particle Filter (PF). The ET calculated using the SEBAL algorithm was used ...
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Extended Abstract
Abstract
The impact of the application of data assimilation (DA) on improving the accuracy of estimates of ET was investigated by applying two different methods of (DA) namely Ensemble Kalman Filter (EnKF) and Particle Filter (PF). The ET calculated using the SEBAL algorithm was used as the observations and the ET calculated according to the FAO 56 was considered as the model outputs. In order to ascertain the performance of these two aforementioned DA methods, the results obtained from three different approaches including a) application of DA using PF method, b) application of DA using EnKF method, and c) application of an open-loop simulation (OL) were compared with the results of another data assimilation system. In this alternative system, soil moisture contents were measured by a soil moisture sensing device (TDR) and the numerical solution of the Richards equation was utilized to calculate soil moisture content (BL). The results indicated that the PF and EnKF methods reduced the average bias error in the soil moisture estimations in the root zone layer by 7% and 9%, respectively, compared to the OL. Furthermore, the PF and EnKF methods were able to reduce the nRMSE of the soil moisture contents by 8% compared to the open-loop simulation (OL). These findings suggest that with the application of the DA, it is possible to improve the accuracy of the ET estimations and therefore, to enhance irrigation management.
Introduction
Data assimilation is a scientific method which integrates information from the actual measurements and the model predictions within a defined framework to enhance the accuracy of the estimations of variables or parameters under investigation. This process comprises of two phases called prediction and update. In the prediction phase, the model estimations are computed using the Monte Carlo simulation method. This process continues until observation data (measurements) becomes available. In the update phase, model estimations and observations are combined, taking into account the confidence level associated with each one of the data sources (observations, and model estimations), resulting in posteriori estimates (updated outcomes). This study focuses on improving the accuracy of the estimates of the soil moisture contents at root zone depth using the ET estimation model suggested for non-standard conditions by FAO 56 (Allen et al., 1998) through the utilization of two data assimilation methods namely the Ensemble Kalman Filter (EnKF) and the Particle Filter (PF). ET was calculated according to the Surface Energy Balance (SEBAL) algorithm using Landsat 8 satellite imagery as observation data for the data assimilation system.
Materials and Methods
In order to ascertain the effectiveness of the data assimilation methods applied, results obtained from a data assimilation system (referred to as BL) which was implemented in two sugar beet fields and two corn fields in the Jovein region were utilized. In the BL system, simulated soil moisture contents of the root zone layer obtained by numerically solving the Richards equation were combined with the soil moisture measurements taken at specific points in the fields using soil moisture sensors (TDR). 51 TDR access tubes were installed in the fields to measure soil moisture contents at various depths using Time Domain Reflectometry (TDR) sensors. Soil moisture measurements were recorded from Khordad to Aban 1399 (write in English calendar).
The essence of data assimilation methods lies in the amalgamation of homogeneous information about the studied phenomenon obtained through different mechanisms. In this study, the observations utilized included ET calculated based on the SEBAL algorithm. In the FAO-56 model, evapotranspiration and soil moisture content of the surface and root zone layers were computed. Since soil moisture contents of the surface and the root zone layers serve as the initial conditions for subsequent simulation steps, data assimilation was applied to the soil moisture content instead of the ET. To achieve this, ET obtained from the SEBAL algorithm was converted into soil moisture content and subsequently used in the data assimilation process.
Conclusion
The average standard deviation of the simulated soil moisture contents (σ) in the PF and EnKF approaches was 36% and 32% lower, respectively, compared to the open-loop (OL) approach. Throughout the growth period, PF and EnKF consistently resulted in lower σ compared to OL in the three fields which were irrigated by center-pivot irrigation systems. However, following each irrigation event in the field M, which was irrigated by a drip irrigation system, σ suddenly increased and became nearly equivalent to OL. This was attributed to the greater depth of irrigation water in this field as compared with the other three fields. On the average, the magnitude of σ change (σΔ), representing the reduction in σ before and after the update, was 0.032 and 0.037 for PF and EnKF, respectively. Consequently, the results suggested that data assimilation reduces the uncertainty of simulation results.
The research findings indicate that data assimilation significantly reduced the BIAS and nRMSE indices compared with the OL approach. The average BIAS for EnKF, PF, and OL was 0.018, 0.020, and 0.028, respectively, while the average nRMSE for the three methods was 17.3%, 17.5%, and 18.9%, respectively. In other words, the use of ET observations obtained from Landsat 8 satellite imagery and the SEBAL algorithm significantly improved the accuracy of the estimation of ET with the FAO-56 model. Therefore, the obtained results suggest that data assimilation can be employed to enhance the accuracy water consumption estimates and to improve irrigation management.
Original Article
River engineering
ali dankoo; Hojjat Allah Yonesi; Mojtaba Saneie
Abstract
Extended Abstract
Introduction
With the occurrence of flood, the velocity and depth of the flow in the river increases and the flow enters the flood plains. The velocity difference between the deeper section and the shallow area causes the transfer of momentum between these areas and complicates the ...
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Extended Abstract
Introduction
With the occurrence of flood, the velocity and depth of the flow in the river increases and the flow enters the flood plains. The velocity difference between the deeper section and the shallow area causes the transfer of momentum between these areas and complicates the flow structure. The formation process of secondary flows and its pattern in compound channels have been investigated by researchers such as:Tominaga & Nezu, 1991. The presence of vegetation on flood plains causes complexity in the analysis of hydraulic problems of compound channels. For example, Hamidifar et al. (2012, 2014), using laboratory measurements, showed that the presence of vegetation reduces the flow through the cross section by about 30%. At the same time as the water level rises during the flood, the deck of the bridges will go under water and the current passing under it will be pressurized. In this condition, the flow field is affected by the presence of vegetation, compound channel and pressurized flow. In this research, the laboratory investigation of these complex conditions has been done.
Methodology
The experiments of this research were done with 3 geometric ratios of the compound cross-section, 3 relative depths, 3 vegetation densities, and control experiments in a compound channel with a length of 10 meters and a width of 1.5 meters. The measurement of the flow velocity parameter, the scouring rate of the bridge pier in the conditions of pressurized flow has been done according to the variables mentioned above.
Results and Discussion
Comparison of depth velocity and logarithmic velocity distribution in the condition without vegetation on the flood plain, the sign shows that in all sections, the distance between the channel bed and the water surface, the difference between the measured velocity values with the logarithmic distribution of the velocity increases. This difference is due to the presence of the bridge deck and the flow retardation. Also, vegetation causes the depth distribution profile of flow velocity to deviate from the curve of logarithmic flow velocity, and the biggest difference will occur in the upstream area between the interface of main channel and flood plain. This phenomenon increases the amount of apparent shear stress between the main channel and the floodplain.
With the increase in the density of vegetation, the percentage of floodplain participation in the total discharge is reduced by 20%. The highest participation percentage of floodplain is about 30% in the state without vegetation. In different densities of vegetation with an increase in relative depth from 0.3 to 0.5, the percentage of floodplain participation in the total discharge is less than 10%. With the increase in the density of vegetation, the difference between the percentage of floodplain participation in different cross section widths has decreased.
Conclusions
The findings of recent research to check hydraulic parameters can be summarized as follows:
- Increasing the density of vegetation increases the longitudinal velocity in the main channel and decreases it in the floodplain.
- Longitudinal velocity and average depth of flow in the main channel in the case without vegetation is lower than the case with vegetation.
-Increasing the relative depth increases the percentage of floodplain participation by an average of 5%, and the increase in vegetation density decreases the floodplain participation by 17% on average.
- With the increase in the vegetation density of the floodplain, the speed changes in the floodplain decrease compared to the main channel.
-The increase in relative depth and density of vegetation increases the non-uniformity of flow lines and finally increases the correction coefficients of kinetic energy and movement size.
-In high-density vegetation, the interference effect of eddies prevents the formation of large secondary currents on the floodplain.
Original Article
Pressurized Irrigation Systems
syeed Hassan mousavifazl
Abstract
Extended AbstractIntroductionAlfalfa is irrigated by drip, strip, Furrow and rain irrigation methods. Surface irrigation methods are unjustifiable and not economical due to the low potential of irrigation efficiency in dry areas. Rain irrigation methods cannot be justified in hot and dry areas due to ...
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Extended AbstractIntroductionAlfalfa is irrigated by drip, strip, Furrow and rain irrigation methods. Surface irrigation methods are unjustifiable and not economical due to the low potential of irrigation efficiency in dry areas. Rain irrigation methods cannot be justified in hot and dry areas due to high evaporation and high water requirement of alfalfa. Alfalfa is a plant whose leaves are sensitive to burns caused by poor quality water as a result of water spraying in the rain irrigation method (Hengeller, 1995). Micro irrigation methods (surface and subsurface drip) are among the alternative methods of rain methods. The subsurface drip irrigation method has not been developed in Iran due to the existence of ambiguities and some dark and unclear points regarding its efficiency for crops (clogged outlets, salt accumulation, and risk of blockage of pipes by roots). These concerns require that before any development of subsurface drip irrigation method for different crops, necessary researches should be done in this field. Therefore, conducting any research on the efficiency of this method for alfalfa, which is a valuable fodder plant but requires a lot of water, seems necessary. This research was conducted with the aim of investigating the effect of subsurface drip irrigation method on alfalfa yield, the amount of water consumed and determining the appropriate distances and depths for sub-pipes. Methodology In order to investigate the effect of installation depth and distance of irrigation strips (laterals) in subsurface drip irrigation method on yield and water use efficiency in alfalfa cultivation, a study was conducted for two years on the farm of Damghan Agricultural Research Station. The design was implemented in the form of split strips based on randomized complete blocks with two factors and three replications. Factors included: 1- Distance of irrigation strips from each other in three levels (80, 100 and 120 cm) 2- Depth of installation of irrigation strips in two levels (30 and 45 cm below the soil surface). Depth of strips installation was considered as the main factor and distances as the sub-factor. The length of each experimental plot was 60 m and the width of the plots for the distances of 80, 100 and 120 cm were selected as 4, 5 and 6 m, respectively. Strips irrigation with a with a diameter of 20 mm with a discharge of 1.6 (lit/hr) and a distance of 60 cm for each dropper were selected. After preparing the ground and sowing the seeds, the subsurface irrigation pipes were placed (according to the treatments) with using the machine. Irrigation water was calculated by Penman-Monteith method and was given to the plant with an irrigation cycle of 4 days.Results and DiscussionThe results showed that the effect of pipe spacing on product yield (dry matter) and water use efficiency was significant, but the effect of pipe installation depth on yield and water use efficiency was not significant. The interaction effect of distance and depth of tapes irrigation on crop yield and water use efficiency was significant. There was no significant difference between crop yield in treatments with lateral distance of 80 and 100 cm. With increasing lateral distance from 80 to 120 cm, crop yield decreased sharply. Due to the yield of treatments and the cost of subsurface drip irrigation, the treatment of lateral distance of 100 and depth of 45 cm was suggested as the superior treatment. Conclusions The subsurface drip irrigation method for perennial crops is one of the efficient and appropriate methods. This method has a much higher efficiency than other irrigation methods due to the reduction of evaporation losses and the increase of irrigation efficiency especially in arid and semi-arid areas. The non-interference of irrigation in this method with the traffic of agricultural machines (especially during harvest) increases the ability and functionality of this method. But one of the problems of this method is the damage of rodents to the sub-pipes under the soil surface, which makes it difficult to determine the places of damage and repair them. Based on the results of this research, to prevent the damage of rodents, it is recommended to fight against these rodents and also to increase the installation depth of secondary pipes up to 50 cm. Clogging of droppers caused by poor filtration performance and penetration into and around the pipes are other problems of this method. To avoid these problems, it is recommended to inject acid and herbicide regularly into the irrigation system.
Original Article
Drainage Engineering
Kasra Ahikhteh; Maryam Navabian; Mohamad Hasan Biglouei
Abstract
Extended Abstract
Introduction
It is possible to effectively control water in paddy fields, prevent flooding problems, and create optimal conditions for the growth of agricultural products with simultaneous and correct management of irrigation and drainage. Due to the high initial cost of the construction ...
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Extended Abstract
Introduction
It is possible to effectively control water in paddy fields, prevent flooding problems, and create optimal conditions for the growth of agricultural products with simultaneous and correct management of irrigation and drainage. Due to the high initial cost of the construction of subsurface drainage, Mole drainage is a suitable and more economical alternative in clay soils. Constructing the mole drain at a critical depth and passing the water through the cracks, improves the soil conditions and removes excess water from the soil surface. Mulqueen (1985), reported that gravel mole drain is a suitable alternative to traditional mole drain. Considering the limited studies in the field of mole drainage, the purpose of this study is to evaluate the performance of low-cost mole drainage for draining excess water from paddy fields and its environmental effects. Therefore, the effect of traditional mole and gravel mole drain on drainage water quality and control of the water table of paddy fields in the mid and end of rice season was investigated.
Materials and Methods
The experiment was conducted in the agricultural year of 2022-2023 in the research farm of the Faculty of Agricultural Sciences, University of Guilan (IRAN). The split-plot experiment was implemented in a randomized complete block design in three replications under the main drainage treatment on two levels: (1) Traditional mole drain (without gravel) and (2) Gravel mole drain and the sub-treatment of irrigation method in two levels: (1) Flood irrigation and (2) Alternative irrigation. In the stages of tillering and harvesting, mid and end season drainage were done respectively. During the drainage period, the water table was measured with a piezometer. By sampling the drainage water, its quality parameters including acidity, electrical conductivity, nitrate, nitrite, phosphate, sulfate, chloride, total suspended and dissolved solids, sodium, calcium, magnesium, and ammonium were measured. The results of the investigated treatments were statistically analyzed using SAS software.
Results and Discussion
With the start of mid season drainage, after one day, the water table reached the middle of the soil profile and more than half of the root development depth was in anaerobic conditions. Five days after the drainage in the traditional mole drain, the depth of root development was in aerobic conditions. The highest value in average acidity and sodium adsorption ratio was 6.99 and 4.65 meq/l respectively in mid season in gravel mole drain and flood irrigation. The highest concentration of ammonium and nitrate in mid season drainage was 0.20 and 0.21 mg/l, respectively, and the highest average electrical conductivity and total dissolved solids at the end season were 3845 µS/cm and 2475 mg/l, respectively, in traditional mole drain and flood irrigation. In mid and end season drainage, the amount of total suspended solids in the mole drain with gravel was 60% and 88% higher than the traditional mole drain, respectively. The highest concentration of nitrite was obtained in the gravel mole drain and flood irrigation with a value of 6.75 mg/l during mid season drainage. The average concentration of phosphate and sulfate in gravel mole drain compared to the traditional mole in mid and end season decreased by 25 and 30%, respectively, and sulfate by 3 and 5.5%. Also, the average concentration of chloride in the gravel mole drain was lower than the traditional one.
Conclusion
The comparison of results indicated that the average amounts of electrical conductivity, total dissolved solids, sodium adsorption ratio, sodium, ammonium, phosphate, sulfate, and chloride of drainage water in mid and end season were lower in gravel mole drain than that in traditional one. The results of statistical analysis showed that the treatment of drainage, irrigation, and time at the level of one and five percent were effective on most of the parameters, while the values of electrical conductivity, total dissolved solids, and nitrite of the drainage water showed that their difference was not significant. The traditional mole drain was more successful in controlling the water table. A comparison of the quality parameters of drainage water with the standard of the Iranian Environmental Protection Organization for the discharge of drainage water into surface waters showed that most of the parameters, except for ammonium and total suspended solids, were within the permissible limits.
