Original Article
Irrigation network management
Omid Raja; Sajjad Veysi; Ali Barzegar
Abstract
Extend AbstractIntouductionMany factors have contributed to the drop in the water table of groundwater, including the increase in cultivated area, decrease in rainfall, climate change, and the continuation of drought in recent years, and withdrawing excessive amounts of surface water sources and groundwater ...
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Extend AbstractIntouductionMany factors have contributed to the drop in the water table of groundwater, including the increase in cultivated area, decrease in rainfall, climate change, and the continuation of drought in recent years, and withdrawing excessive amounts of surface water sources and groundwater from unauthorized wells, which has faced serious challenges in the water sector in Alborz province. The Hashtgerd plain is located in the Alborz province. The current situation of the Hashtgerd plain is the result of a series of human and natural factors over the past few decades, and the restoration and balance of the underground water of the plain is a priority. According to long-term statistics, the groundwater level has decreased by 19.8 m in 29 years (1990-2019) on average, there is a drop in the groundwater level of about 68 cm. per year. The total aquifer deficit is 487.85 million cubic meters, and the average annual amount of the aquifer deficit is 16.82 million cubic meters (6.2%). Given these conditions, it is essential to apply effective solutions for optimal and efficient water management.MethodologyThe purpose of this study was to provide practical and low-cost solutions to save water consumption in Hashtgerd Plain. There are different solutions with minimal cost, such as improving irrigation efficiency, changing the planting date, and different patterns of deficit irrigation. The approach of this study is to present and examine solutions that do not require changing the irrigation system or even changing the cultivation pattern and also not reducing the cultivated area in the region. It is the examination of the solutions that can be implemented at the lowest possible cost without adversely affecting the livelihood of farmers. The objective of the study was to reduce water consumption or prevent from excessive groundwater of Hashtgerd plain aquifer. The proposed solutions do not require new tools such as precision leveling machines and, so on. Each of the above strategies was evaluated based on the actual conditions in the region. The main objective was to evaluate and estimate the water requirements of the dominant crops in the Hashtgerd Plain, and to present different scenarios for improving irrigation efficiency according to the superior conditions in the region. The feasibility of saving water consumption through strategies to change the planting date and deficit irrigation was evaluated using the AquaCrop 6.0 model.Results and discussionIn this study, the AquaCrop model was used to simulate the yield of crops and the amount of water use in the region. The calibration of the AquaCrop model for regional conditions has demonstrated that the AquaCrop model is capable of predicting crop yield with the lowest relative error (RE) for wheat, barley, fodder corn, and alfalfa for the plains during the calibration phase of the simulation model. According to the levels of efficiency improvement in different regions and for different crops, it will lead to savings of 17.7 million cubic meters (5.9%) in the amount of allocated water consumption. This will can provide the possibility of supplying water to a larger area of land without reducing yield under water scarcity conditions. The outcomes of the scenario involving a change in planting date through AquaCrop model simulation demonstrated that this management pattern has the potential to reduce water consumption by 2.4 million cubic meters (0.8%) in the region. In addition, different levels of deficit irrigation can save 19.3 million cubic meters of water consumption.ConclusionThe obtained results show that in many cases, it is possible to provide without modern facilities and huge costs, applying different scenarios such as improving efficiency, changing planting dates and deficit irrigation has achieved significant savings in the required irrigation water consumption. Naturally, the share of each crop in the amount of savings is proportional to the average water consumption per hectare and the area of land under each crop. In general, the AcuCrop model can be used as a practical tool for simulating crop yield and evaluating management scenarios.
Original Article
River engineering
Iman Karimi Sarmeydani; Mohammad Heidarnejad; Aslan Egdernezhad
Abstract
Extend Abstract
Intouduction
Groynes at water intake locations significantly increase the flow diverted from rivers by optimizing incoming water control. Vaghefi and Ghodsian (2017) experimentally studied flow patterns around a T-shaped Groyne within a 90-degree arc using a moving bed. Shaker and Kashfipour ...
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Extend Abstract
Intouduction
Groynes at water intake locations significantly increase the flow diverted from rivers by optimizing incoming water control. Vaghefi and Ghodsian (2017) experimentally studied flow patterns around a T-shaped Groyne within a 90-degree arc using a moving bed. Shaker and Kashfipour (2013) compared flow velocity and shear stress distribution with and without Groynes. Behnam-Talab et al. (2018) simulated porous Groynes using FLOW-3D software. Shahinejad et al. (2022) applied a multi-objective algorithm to optimize T-shaped Groyne dimensions, achieving superior results, compared to previous designs. Zare and Honer (2016) investigated how simple Groynes reduce lateral erosion in river arches under laboratory conditions, emphasizing the influence of Groynes on erosion patterns. These studies collectively highlight the importance of Groyne design in enhancing water extraction and mitigating erosion.
The review of literatures confirms that both laboratory and numerical studies have been conducted to examine the characteristics of various types of Groynes and the impact of flow patterns on them. However, there is a lack of studies addressing the simultaneous application and comparison of numerical and data-driven models in the investigation of geometric and hydraulic characteristics, particularly concerning the effect on the amount of diverted discharge from a canal into intake featuring T-shaped and L-shaped Groynes. Consequently, this research aims to evaluate the performance of two MLMs, specifically SVM and GEP in comparison with the Computational Fluid Dynamics (CFD)-based FLOW-3D model, on a laboratory scale.
Materials and Methods
Groynes play a crucial role in river engineering by regulating river flow. This study assesses the efficacy of two machine learning algorithms—support vector machine (SVM) and gene expression programming (GEP)—in comparison with FLOW-3D software for simulating diverted flow in a laboratory setting. The experimental model was tested in a laboratory flume with T-shaped and L-shaped Groynes positioned at 90 and 135-degree angles to channel the discharge into the intake system. The machine learning models incorporated three independent variables: the flow Froude number, the angle of water intake, and the relative length of the Groynes. Out of 96 laboratory data points, 70% were allocated for model training and 30% for model testing. Model performance was assessed using the root mean square error (RMSE), mean absolute error (MAE), and coefficient of determination (R²) indices.
Results and Discussion
The results indicated that the GEP model surpassed the SVM model. For the L-shaped Groyne, the values for (R², MAE, RMSE) during both the training and testing phases were (0.9325, 0.9878, 1.2536) and (0.9836, 0.4102, 0.6325), respectively. For the T-shaped Groyne, the corresponding values were (0.9025, 1.2534, 1.8502) during training and (0.9873, 0.3337, 0.4972) during testing. In the FLOW-3D model, after calibration and validation, a Manning's roughness coefficient of 0.035 and the Prandtl's mixing length model were chosen for turbulence simulation. The performance indices during the testing phase for the L-shaped and T-shaped Groynes were (0.9607, 0.9363, 1.2070) and (0.9513, 1.1256, 1.3759), respectively. The GEP model showed a relative advantage over the FLOW-3D model.
Concutions
This study compares the performance of MLMs (SVM, GEP) with FLOW-3D in simulating diverted flow using T-shaped and L-shaped Groynes. Results from laboratory flume tests showed GEP outperformed SVM and FLOW-3D, particularly in simulating flow diversion, evaluated by RMSE, MAE, and R² performance indices.
Original Article
Pressurized Irrigation Systems
Mohammad Joleini; Ardalan Zolfagharan
Abstract
Extended AbstractIntroductionRazavi Khorasan province is one of Khorasan provinces in northeastern of Iran, the center of this province is Mashhad. The area of this province is 118854 square kilometers. Due to having high evaporation potential and low rainfall, mostly associated with inappropriate distribution, ...
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Extended AbstractIntroductionRazavi Khorasan province is one of Khorasan provinces in northeastern of Iran, the center of this province is Mashhad. The area of this province is 118854 square kilometers. Due to having high evaporation potential and low rainfall, mostly associated with inappropriate distribution, this region is among the dry and semi-arid regions of our country, so that water is considered the most important factor limiting the development of agriculture. Nowadays, limitations in water resources has made it necessary to create ways to increase water productivity. This is a proof of the importance of careful planning and finding the use of different irrigation methods to increase water productivity in agricultural activities. Reviewing the sources indicated that the volume of water used in the cherry orchards varied in different regions and with different irrigation systems. This research aims to measure the volume of applied water, the yield, and the productivity of cherry under the management of farmers in three plains: Mashhad - Chenaran, Torghabe - Shandiz, and Nyshabor, and to compare the volume of applied water with the volume of water requirement of cherry mentioned in the national document and calculated by Penman- Monteith method using meteorological data.MethodologyThis project was carried out in the field in order to determine the optimum water requirement of cherry in the orchards under the management of farmers during one cropping season (2021). Three plains: Mashhad - Chenaran, Torghabe – Shandiz, and Nyshabor were selected in Razavi Khorasan province, these plains have the largest area under cherry cultivation in the province. Based on the data required to implement the project, a questionnaire containing necessary information and logical conclusion was prepared. The required data of the selected farms in each plain were either measured or gained through interviews with the farmer or were calculated and completed according to the data obtained. The measurements were carried out in type of water source, irrigation network, irrigation method, and water source discharge. The field and area under cultivation of cherry, variety, planting arrangement, planting date, soil texture, electrical conductivity of irrigation water and soil saturation extract, date of first irrigation, irrigation cycle, different irrigation methods, etc. The volume of applied water were compared with the net irrigation water requirement estimated by the Penman- Monteith method using the last 10 years meteorological data (2011 to 2021) and also with the national water document values. Crop yield was recorded at the end of the growing season and water productivity was calculated as the ratio of yield to total water (irrigation applied water and effective rainfall). Results and DiscussionIn Razavi Khorasan province, underground water sources are facing with deficit. Therefore, efforts towards better use water and reducing exploitation of underground water resources are inevitable. In this project, the water given by the farmers for cherry production during one cropping season was measured in three plains of Mashhad - Chenaran, Torghabe – Shandiz, and Nyshabor, without interfering farmer’s irrigation schedule; these plains had the largest area under cherry cultivation in Razavi Khorasan province. The method of irrigation of the fields was surface and drip irrigation. The results showed that the volume of applied water in Mashhad - Chenaran, Torghabe - Shandiz and Nyshabor plains were 7760, 7590 and 7740 m3/ha, respectively. The average amount of applied water, the amount of cherry yield and the water productivity in those plains were 7799 m3/ha, 7049 kg/ha and 0.907 kg/m3, respectively. Also, the average volume of irrigation water, yield, and productivity of water in the surface irrigation method were 8029 m3/ha, 6489 kg/ha, and 0.8013 kg/m3 respectively; for drip irrigation method the figures were 7638 m3/ha, 8439 kg/ha, and 0.972 kg/m3 respectively. ConclusionsThe results showed that the average volume of water, yield and water productivity in three plains were 7799 m3/ha, 7049 kg/ha, and 0.907 kg/m3 of water, respectively. The difference between the volume of applied water, performance and water efficiency in two methods of surface and drip irrigation was significant. Under the drip irrigation system, comparing to surface irrigation method, the volume of applied water was 5% less (7638 cubic meters per hectare versus 8029 cubic meters per hectare), the yield was 14% higher (7439 kg/ha versus 6489 kg/ha) and the water productivity was about 20% higher (0.972 kg/cubic meter of water versus 0.813 kg/cubic meter of water).
Original Article
Pressurized Irrigation Systems
Amal Savaedi; mohamadreza zayeri; Mehdi Ghomeshi; Mehdi Daryaee
Abstract
Extended Abstract
Introduction
Dams, as barriers constructed across rivers, are comprised of essential components such as the body, spillway, and drainage systems. Various labyrinth spillway designs, including triangular, trapezoidal, circular, and polygonal horizontal ...
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Extended Abstract
Introduction
Dams, as barriers constructed across rivers, are comprised of essential components such as the body, spillway, and drainage systems. Various labyrinth spillway designs, including triangular, trapezoidal, circular, and polygonal horizontal layouts, extend the effective flow path over a fixed width compared to linear spillways. Researchers aim to identify optimal designs balancing high performance and cost-efficiency. Recent advancements highlight the integration of optimization methods and computational fluid dynamics (CFD) to improve labyrinth spillway designs. Studies have explored the hydraulic and geometric factors affecting discharge coefficients (Cd) and flow velocity. Research includes the application of artificial intelligence (AI) models such as artificial neural networks (ANNs), adaptive neuro-fuzzy inference systems (ANFIS), and regression techniques to predict Cd. Notable contributions demonstrate that AI models effectively capture complex nonlinear relationships between geometric parameters and flow rates, outperforming traditional methods. For instance, models like support vector machines (SVM) and adaptive regression spline (MARS) have demonstrated high accuracy in predicting Cd.
Despite advancements, precise predictive models for labyrinth spillways with harmonic plans remain underdeveloped. This study addresses this gap by introducing new methodologies, including SVM, random forests (RF), and MARS, to predict Cd. It also quantifies the influence of dimensionless parameters on Cd, synthesizing experimental data to enhance understanding and bridge existing research gaps.
Methodology
In this study, soft computing models were developed using experimental results from Arham Namazi and Mozaffari (2023) and Yıldız et al. (2024). To evaluate the accuracy of proposed soft computing equations in estimating the discharge coefficient (Cd) for circular labyrinth weirs arranged harmonically in open channels, the following experimental data were utilized: Yıldız et al. (2024): conducted 215 experiments for weirs with three different heights (P = 20 cm, P = 30 cm, and P = 40 cm) and three different cycle numbers (N = 2, N = 3, and N = 4). Arham Namazi and Mozaffari (2023): performed 18 experiments with a fixed weir height (P = 15 cm) configured as a single cycle (N = 1).
In total, 233 experimental results were collected for soft computing-based modeling. Among these, 175 samples (75%) were used for model training, and 58 samples (25%) were allocated for testing the developed models.
Results and Discussion
Violin plots for both measured and predicted data inferred by various machine learning models are presented. Violin plots are typically used to compare the distribution of data across different groups in terms of their shape. Additionally, a small box plot is embedded within each violin plot, where the ends of the rectangle represent the first and third quartiles, and the central point denotes the median. it can be observed that all three models—RF, SVM, and MARS—predict similar first and third quartiles and medians, compared to the measured data. In contrast, the first or third quartiles in the equations proposed by Arham Namazi and Mozaffari (2023) and Equation 18 show significant deviations from the measured values. Furthermore, from the perspective of the overall data distribution, the SVM and MARS algorithms demonstrate distributions more similar to the measured data compared to the RF algorithm. This highlights the superior predictive capability of the support vector machine (SVM) approach.
Conclusions
Labyrinth weirs are consistently proposed as an effective solution for enhancing flood discharge efficiency, particularly in cases where space for weir construction is limited. These weirs have a longer crest length compared to linear weirs, allowing floods to pass at shallower depths. Due to the complex relationship between the discharge coefficient and its associated parameters, empirical equations often fail to predict the discharge coefficient with acceptable accuracy.
In this study, three different machine learning models were developed to predict the discharge coefficient of semicircular labyrinth weirs with harmonic designs. The results confirm the advantages of the Support Vector Machine (SVM) algorithm. Key findings of the study are summarized as follows:
Parameter Sensitivity Analysis: To minimize prediction errors in the machine learning models, a sensitivity analysis was conducted to identify the relative head is importance of different input parameters. Based on this analysis, five input combinations were designed and applied to the machine learning models.
Optimal Input Combination: Statistical comparisons between predicted and experimental data revealed that the optimal input combination effectively predicted the discharge coefficient for this type of weir.
Model Performance: Using the best input combination, the results showed that the SVM and MARS algorithms outperformed tree-based models, such as Random Forest (RF), in prediction accuracy for harmonic weirs with varying cycles.
MARS Model Evaluation: Although the MARS model performed well, comparisons with other regression models from previous studies demonstrated that MARS delivered satisfactory and improved accuracy over those models.
Original Article
Hydraulic
Mehrdad Asadi; Mohammad Javad Monem; Jamal Mohammad Vali Samani
Abstract
Extended Abstract
Introduction
Sediment accumulation is a persistent challenge in the operation of diversion dams, which are critical infrastructures for water diversion and flow management. Sediments tend to deposit in front of intake structures, obstructing water flow and impairing operational efficiency. ...
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Extended Abstract
Introduction
Sediment accumulation is a persistent challenge in the operation of diversion dams, which are critical infrastructures for water diversion and flow management. Sediments tend to deposit in front of intake structures, obstructing water flow and impairing operational efficiency. Sediment flushing, achieved through sluiceways equipped with control gates, is an effective approach to alleviate these deposits. However, one of the key design parameters the gate opening-to-width ratio (a/b) significantly influences flushing efficiency, though no standardized guideline for optimizing this ratio currently exists. This study investigates how the gate opening-to-width ratio (a/b) and sluiceway width (Ws) affect sediment flushing performance using the FLOW-3D computational fluid dynamics (CFD) model. Simulations under controlled flood conditions provide insights into optimal design parameters to enhance sediment flushing efficiency, aiming to inform best practices in hydraulic design.
Methodology
This study employs FLOW-3D, a high-resolution CFD software that solves the Navier-Stokes equations for incompressible, turbulent flow. The model integrates the RNG k-ε turbulence model, which accurately captures complex shear flows and turbulent interactions, making it ideal for studying sediment transport in hydraulic structures.
Simulations were conducted under constant flood inflow conditions, with variations in the gate opening-to-width ratio (a/b) for each sluiceway width (Ws). To ensure model accuracy, results were validated against experimental data from prior research, confirming the model's ability to reproduce sediment flushing patterns. The study examined sluiceway widths from 0.58 to 1.83 times the intake channel width (Wi), assessing how each width and its corresponding a/b ratio affected flushing performance. Key parameters such as Froude number (Fr), gate dimensions, and sluiceway configurations were analyzed to determine their impact on sediment removal efficiency.
Results and Discussion
Results indicated that a Froude number between 0.16 and 0.3 produced the best flushing efficiency, providing sufficient flow energy to mobilize and transport sediments while minimizing turbulence and backflow. Analysis of sluiceway widths showed that as the width increased, flushing efficiency declined due to reduced flow velocities. A narrower sluiceway width of 0.58Wi exhibited high sediment removal rates, but this aggressive flushing risked destabilizing upstream structures due to increased erosive forces. Conversely, a wider sluiceway (1.83Wi) promoted sediment deposition, as lower flow energy led to ineffective flushing and potential blockages.
An optimal range for sluiceway width between 1.0 and 1.15 times the intake width (Wi) was identified. This range provided adequate flow velocity and shear stress to minimize sediment deposition within the sluiceway and control downstream sediment transport without risking erosion of upstream structures.
Regarding the gate opening-to-width ratio (a/b), simulations showed that an a/b ratio of 0.5 consistently enhanced flushing efficiency across different sluiceway widths. Lower ratios (<0.5) resulted in reduced flushing due to insufficient flow energy, while higher ratios (>0.5) created localized turbulence and erosion, compromising overall system stability. Optimizing the a/b ratio at 0.5 balanced sediment mobilization with flow stability, achieving efficient flushing without excessive backflow or structural impacts.
The study further evaluated sediment transport length, or the effective flushing range, within the sluiceway. With an a/b ratio of 0.5, the effective sediment transport distance reached approximately 60% of the sluiceway length for narrower configurations, though this range decreased with increased sluiceway widths. These results underscore the need to balance sluiceway width and gate ratio to maintain effective sediment transport along the sluiceway length.
Conclusion
This research presents essential guidelines for enhancing sediment flushing in diversion dams through optimized sluiceway design. A Froude number between 0.16 and 0.3, combined with an a/b ratio of 0.5, was found to maximize sediment removal efficiency. An optimal sluiceway width between 1.0 and 1.15 times the intake width (Wi) further improved sediment transport, achieving efficient flushing with controlled downstream flow and minimizing upstream erosion.
Original Article
Irrigation network management
Hassan Ojaghlou; Zahra Amiri Abdobochali; Sepideh Oroumi
Abstract
Extended AbstractIntroductionPopulation pressures continue to undermine effective land and water management in many developing countries. Improving water productivity in agricultural lands is essential for enhancing production and adapting to the water scarcity crisis. Rainfed lands play a crucial role ...
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Extended AbstractIntroductionPopulation pressures continue to undermine effective land and water management in many developing countries. Improving water productivity in agricultural lands is essential for enhancing production and adapting to the water scarcity crisis. Rainfed lands play a crucial role in food production. Breeding and crop improvement are two important strategies for increasing water productivity. Supplemental irrigation is considered one of the crop improvement managements in rainfed lands. This management approach involves providing one or two irrigations during critical growth periods, which can significantly improve yield and water productivity on rainfed lands. However, the effectiveness of supplemental irrigation depends on accessibility to water resources, water quality, soil fertility, and other important factors. Therefore, locating suitable rainfed areas for implementing supplemental irrigation will be the first step. The area under cultivation of rainfed lands in Zanjan Province is substantial, covering 338,000 ha. It is recognized as one of the provinces with a high capacity for producing rainfed crops in the country. This paper presents a comparative analysis of the Analytic Hierarchy Process (AHP) in the context of decision-making for supplemental irrigation site selection using Geographic Information Systems (GIS) in Zanjan Province. For this purpose, several criteria were employed in the selection process, based on the literature concerning factors that influence supplementary irrigation performance. MethodologyIn this research, Zanjan Province was selected as the study area. The criteria examined in this research encompass the accessibility of water resources, water quality, soil properties, climatic factors, topography, and road accessibility, including its sub-criteria. The AHP method was employed to prioritize rainfed lands for supplemental irrigation. The AHP process consists of three key components: identifying a hierarchy of objectives, criteria and alternatives; conducting pairwise comparisons of the criteria; and integrating the results from these comparisons to determine the relative importance across all levels of the hierarchy. The factors influencing site selection exhibit various characteristics; some are descriptive and can vary in quantity, while others possess numerical values. Consequently, it is essential to standardize the values and weights of each factor. Zoning maps for each sub-criterion were prepared as information layers using ArcGIS software, and subsequently, all prepared maps were re-scored through a reclassification process. The pairwise comparison tables for the AHP method were generated using the extAHP plugin in ArcGIS software, establishing the weight coefficients for the criteria. The land classification map was created by overlaying the zoning maps corresponding to each criterion while considering the assigned weights. Finally, by integrating the obtained map with the rainfed land map of Zanjan Province, suitable rainfed fields for supplementary irrigation were determined. Results and DiscussionThere are generally no significant restrictions in most areas of Zanjan Province regarding the water quality, soil properties, climatic factors, road accessibility, and topography for implementing supplemental irrigation. However, in certain regions, limited accessibility to water resources has caused restrictions. The access to water resources received the highest weight and importance in the AHP prioritization method, while the water quality criterion ranked second in significance and influence on decision-making. Based on classified land maps of Zanjan Province, the central and eastern regions received higher scores for implementing supplemental irrigation. Additionally, the central areas of rain-fed lands were identified as having a high potential for supplemental irrigation capability. The area and percentage of various land classes were calculated. Approximately 44.2% of the province's land is classified as either completely suitable or suitable for supplemental irrigation, while about 32.4% falls within the moderate range, and 23.4% is deemed unsuitable. Furthermore, around 59.6% of rainfed land is classified as suitable or completely suitable, about 27.8% falls within the moderate range, and 12.6% is considered unsuitable. ConclusionsImproving yield and water productivity through supplemental irrigation in rainfed areas is a crucial crop improvement strategy. Zanjan Province, with its significant area of rainfed land, relatively favorable rainfall, and good soil quality in most regions, possesses significant production and productivity potential in these agricultural areas. In this research, suitable rainfed areas in Zanjan Province were identified for supplemental irrigation by considering relevant criteria and utilizing the AHP method. Approximately 59.6.2% of the areas in the Zanjan Province, particularly in the central and eastern regions of Zanjan, were identified as suitable or fully suitable for supplemental irrigation, while the remaining lands faced low to severe limitations. Ultimately, the effectiveness of the AHP method can be assessed in feasibility studies for the implementation of viable water projects, and its use is recommended during the initial project identification phase. The final selection of suitable locations for implementing supplemental irrigation is suggested by integrating the results obtained from AHP with findings from field surveys and regional conditions. It is indicated that the water resources required for implementing supplemental irrigation can be harvested from the current permitted allocations, without any new extraction of water resources.
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