دانشگاه تبریزدانش آب و هیدرولیک3092-611435420251222Investigation of Combined Leakage Control Methods with Simultaneous Numerical Analysis of the Cutoff Wall and Clay Blanket in Earth-fill Damsبررسی روشهای ترکیبی کنترل نشت با تحلیل عددی همزمان دیوار آببند و پتوی رسی در سد خاکی1142143510.22034/hws.2025.66816.1023FAابراهیماسدیاستادیار دانشگاه شهید مدنی آذربایجان - گروه مهندسی عمران، تبریز، ایرانمهدیسلطانی ستوبادیدانشجوی کارشناسی ارشد، مهندسی عمران -آب و سازههای هیدرولیکی- دانشگاه شهید مدنی آذربایجان، تبریز، ایرانتوحیدامیدپور علویاندانشجوی دکترای، مهندسی عمران -آب و سازههای هیدرولیکی-دانشگاه مراغه، مراغه، ایرانJournal Article20250517Earth dams, as critical hydraulic structures, are essential for water resource management, enabling irrigation, flood control, and hydropower generation, but their performance is often compromised by seepage through the dam body and foundation, which reduces storage capacity, increases pore water pressure, and risks structural instability, potentially leading to catastrophic failure. This study evaluates the performance of two widely used seepage control methods—cutoff walls and clay blankets—based on the specifications of an earthen dam in East Azerbaijan, employing numerical modeling with GeoStudio’s Seep/W module to analyze their effectiveness in reducing seepage and controlling pore water pressure. The research focuses on key design parameters, including the depth and thickness of the cutoff wall, the length and thickness of the clay blanket, and the permeability of the dam foundation, which significantly influence seepage behavior and structural stability. The numerical model was developed using detailed geotechnical data from the dam site, incorporating soil properties, hydraulic conductivity, and boundary conditions to simulate real-world seepage patterns under steady-state conditions. The cutoff wall, modeled with depths ranging from 10 to 20 meters and thicknesses from 1 to 3 meters, demonstrated superior performance, with a configuration of 15 meters depth and 2 meters thickness reducing seepage by 70–90%, as it effectively intercepts flow paths through the permeable foundation layers, significantly lowering the hydraulic gradient and mitigating pore water pressure buildup. In contrast, the clay blanket, tested with lengths of 50 to 100 meters and thicknesses of 0.5 to 2 meters, achieved a seepage reduction of 30–50% with a configuration of 93 meters length and 1.5 meters thickness, primarily by increasing the seepage path length across the upstream face, though its impact on pore water pressure was less pronounced due to its surface-level application, which does not penetrate deep foundation layers. The numerical simulations revealed that the cutoff wall’s effectiveness stems from its ability to create a low-permeability barrier deep within the foundation, reducing the risk of piping and internal erosion, while the clay blanket’s performance is limited by its dependence on the foundation’s inherent permeability and susceptibility to cracking under differential settlement. Economically, the cutoff wall accounted for 49.8% of the total project costs, driven by high material and excavation expenses, whereas the clay blanket constituted 50.2% of the budget, benefiting from simpler construction techniques and lower excavation requirements, making it a more viable option for shorter dams or sites with less permeable foundations. However, the cutoff wall’s superior seepage reduction per unit cost highlights its cost-effectiveness for large-scale projects where long-term stability is critical. A key innovation of this study is the proposal of a hybrid seepage control strategy combining a cutoff wall and a clay blanket to optimize both performance and cost. The combined model, integrating a cutoff wall with a reduced depth of 12 meters and a clay blanket with a thickness of 1 meter, achieved an 85% reduction in seepage, surpassing the clay blanket’s standalone performance and approaching the cutoff wall’s effectiveness, while reducing execution costs by 10% compared to implementing either method independently. This hybrid approach leverages the cutoff wall’s deep seepage barrier to control foundation flow and the clay blanket’s upstream coverage to extend the seepage path, creating a synergistic effect that enhances overall stability. Sensitivity analyses further confirmed that foundation permeability significantly influences both methods’ performance, with highly permeable foundations requiring deeper cutoff walls, while moderately permeable foundations benefit more from the hybrid configuration. The findings underscore the importance of site-specific geotechnical assessments in seepage control design, as variations in soil properties and hydraulic conditions can alter the optimal configuration. From a practical perspective, the proposed hybrid solution offers significant advantages for earthen dam projects, reducing construction costs and improving long-term performance, which is particularly valuable in regions with limited budgets or challenging geological conditions. The 85% seepage reduction achieved by the combined approach minimizes water loss, enhancing the dam’s storage efficiency and supporting sustainable water management, while the 10% cost savings can translate into substantial financial benefits for large-scale infrastructure projects. These results also have broader implications for civil engineering, as the hybrid strategy can be adapted to other hydraulic structures, such as levees or canal embankments, where seepage control is a concern. The study’s reliance on GeoStudio’s Seep/W module highlights the power of numerical modeling in optimizing hydraulic design, allowing engineers to simulate multiple scenarios and refine configurations without costly field trials. However, limitations such as the model’s assumption of steady-state conditions and homogeneous soil properties suggest the need for future research to incorporate transient seepage, layered soil profiles, and long-term material degradation effects, such as clay blanket cracking or cutoff wall deterioration. Field validation of the hybrid solution in operational dams would further confirm its practical efficacy, particularly under varying hydraulic loads and environmental conditions. Additionally, exploring alternative materials, such as geosynthetic clay liners or concrete diaphragms, could enhance the hybrid system’s performance and durability. This research provides a robust framework for designing seepage control measures in earthen dams, demonstrating that a combined cutoff wall and clay blanket approach can achieve high efficiency at reduced costs, offering a practical and innovative solution for improving the stability and sustainability of hydraulic infrastructure in large-scale civil engineering projects, with potential applications across diverse geological and hydrological contexts.سدهای خاکی، سازههای حیاتی برای مدیریت منابع آب، با چالش نشت از بدنه و پی مواجهاند که میتواند ظرفیت ذخیرهسازی را کاهش داده و ناپایداری سازه را به دنبال داشته باشد. این پژوهش عملکرد دیوار آببند و پتوی رسی را برای کنترل نشت در یکی از سدهای خاکی آذربایجان شرقی با مدلسازی عددی در نرمافزار GeoStudio (ماژول Seep/W) بررسی کرد. تأثیر عمق و ضخامت دیوار آببند، طول و ضخامت پتوی رسی، و نفوذپذیری پی بر نشت و فشار آب منفذی تحلیل شد. نتایج نشان داد دیوار آببند با عمق ۱۵ متر و ضخامت ۲ متر، نشت را ۷۰–۹۰٪ کاهش داده و فشار آب منفذی را بهطور مؤثری کنترل میکند، درحالیکه پتوی رسی با طول ۹۳ متر و ضخامت ۵/۱ متر، نشت را ۳۰–۵۰٪ کاهش داد، اما در کنترل فشار آب منفذی کمتر مؤثر بود. ازنظر اقتصادی، دیوار آببند ۴۹/۸٪ و پتوی رسی ۵۰/۲٪ از هزینههای پروژه را تشکیل میدهند، اما دیوار آببند عملکرد بهتری نسبت به هزینه دارد و پتوی رسی برای سدهای کوتاهتر به دلیل اجرای سادهتر مناسبتر است. نوآوری پژوهش، ارائه راهکار ترکیبی دیوار آببند (عمق ۱۲ متر) و پتوی رسی (ضخامت ۱ متر) است که نشت را ۸۵٪ کاهش داده و هزینهها را ۱۰٪ کمتر میکند. این یافتهها راهکاری بهینه برای طراحی سدهای خاکی ارائه میدهند.https://hws.tabrizu.ac.ir/article_21435_fd5d562fabd997f129388f46a5b8c8ba.pdfدانشگاه تبریزدانش آب و هیدرولیک3092-611435420251222Comparison of Wind Drift and Evaporation Losses and Performance Evaluation Indices in Three Sprinkler Irrigation Systems with Emphasis on Water Resource Sustainability (Case Study: Poldasht County)مقایسه تلفات تبخیر و بادبردگی و شاخصهای ارزیابی عملکرد در سه سامانه آبیاری بارانی با تأکید بر پایداری منابع آب (مطالعه موردی: شهرستان پلدشت)15262145110.22034/hws.2026.70065.1036FAامیرنورجواستادیار، مرکز تحقیقات و آموزش کشاورزی و منابع طبیعی استان آذربایجان غربی، سازمان تحقیقات، آموزش و ترویج کشاورزی، ارومیه، ایران.0000-0003-4176-0375مجتبیرضاییاستادیار پژوهشی، موسسه تحقیقات برنج کشور، سازمان تحقیقات آموزش و ترویج کشاورزی ، رشت، ایرانمرتضیکمالیموسسه تحقیقات برنج کشور . سازمان تحقیقات، آموزش و ترویج کشاورزی، رشت ، ایرانJournal Article20250911Introduction<br />Water is the most critical and limiting input for agricultural production in Iran, where severe water scarcity poses substantial threats to food security and sustainable agriculture. Factors such as population growth, prolonged droughts, and the over-extraction of water resources have intensified the water crises across the country, leading to adverse social and economic consequences. Given that over 90% of the country’s renewable water resources are consumed in the agriculture sector, optimizing irrigation efficiency through the adoption of modern irrigation technologies has become an urgent necessity. Efficient water management not only conserves scarce resources but also enhances crop yield and mitigates environmental impacts. In this context, the present study was designed to comprehensively evaluate the performance of three sprinkler irrigation systems, namely the conventiona gun sprinklers, the spray boom, and a farmer-modified water distribution system, under field conditions along the Aras River in Poldasht, West Azerbaijan, Iran. The objective was to provide a detailed comparison of these systems in terms of water distribution uniformity, Christiansen’s uniformity coefficient (CU), application efficiency (Ea), and losses due to evaporation and wind drift. By systematically assessing these performance indicators, the research aimed to identify the most effective and sustainable irrigation method for semi-arid agricultural regions, where water scarcity and environmental challenges render efficient irrigation practices critical for crop productivity and long-term resource management. Furthermore, the study explored the potential of low-cost, site-specific modifications implemented in the farmer-designed systems to improve water use efficiency and reduce operational losses. The findings are intended to offer practical insights for optimizing irrigation strategies in similar agro-climatic zones.<br />Materials and Methods<br />The study was conducted on 59 hectares of privately owned farmland characterized by sandy loam soil, located in a semi-arid cold climate in Poldasht, West Azerbaijan, Iran. The site is situated along the Aras River at an elevation of 874 meters above sea level. Field experiments were carried out during July, August, and September 2018 to evaluate the performance of three sprinkler irrigation systems. The assessment focused on key performance indicators including distribution uniformity (DU), Christiansen’s uniformity coefficient (CU), application efficiency (Ea), and losses due to evaporation and wind drift. To quantify water distribution, catch cans were strategically placed in multiple rows across the irrigation strips, and the overlapping effects of adjacent irrigation lines were incorporated into the calculations to accurately determine the actual water depth received at each location. Soil physical and chemical properties, including texture, bulk density, infiltration rate, pH, and electrical conductivity, were analyzed to understand their influence on water movement and retention. Water quality parameters were also measured to ensure suitability for irrigation. Additionally, the farmer-designed system was adjusted and optimized under field conditions, Modifications included alterations to lateral pipes and nozzle configurations aimed at improving water application uniformity and reducing operational losses.<br />Results and Discussion<br />The results of the field evaluation revealed significant differences in performance among the three sprinkler irrigation systems. The spray boom system demonstrated the highest efficiency and uniformity, with average Christiansen’s uniformity coefficient (CU), distribution uniformity (DU), and application efficiency (Ea) of 94.7%, 91.1%, and 85.8%, respectively, indicating excellent irrigation performance. In contrast, the gun sprinkler system exhibited the lowest performance, with CU = 68.7%, DU = 64.9%, and Ea =67.6%, and recorded the highest evaporation and wind drift losses, averaging 22.7%. These performance variations were largely attributed to factors such as spray height, droplet size, and wind conditions, which significantly influenced water distribution and losses under field conditions. The farmer- modified water distribution system, which incorporated on-farm modifications including direct water application via lateral pipes and te removal of standard nozzles, achieved an acceptable performance level with CU = 89.9%, DU = 85.7%, and Ea = 94.2%. Evaporation and wind losses were negligible in this system due to the reduced exposure of water droplets to the atmosphere. The data further indicated that overlapping of irrigation lines played a critical role in achieving more uniform water distribution, particularly for the spray boom and gun sprinkler systems. Overall, the findings underscore the importance of system design, operational adjustments, and site-specific adaptations in achieving high irrigation efficiency and minimizing water losses.<br />Conclusion<br />The study demonstrated that the type of sprinkler irrigation system, along with its design and operational practices, has a decisive influence on water distribution uniformity, application efficiency, and losses due to evaporation and wind drift. Among the three systems evaluated, the spray boom system exhibited superior performance, achieving excellent uniformity and efficiency, whereas the gun sprinkler system showed the poorest results, primarily due to higher droplet height and susceptibility to wind. The farmer-designed water distribution system, despite being developed empirically, performed effectively, underscoring the potential of low-cost, site-specific modifications to enhance irrigation efficiency. These findings indicate that adopting spray boom systems or modified on-farm water distribution methods can substantially improve irrigation efficiency, reduce water losses, and promote sustainable water management in semi-arid and windy regions. Moreover, periodic evaluation of system performance and installation of proper filtration to prevent nozzle clogging are essential for maintaining long-term efficiency and reliability. Overall, this study offers practical insights for optimizing sprinkler irrigation practices and encourages the adoption of cost-effective, farmer-adapted solutions in water-scarce regions.با توجه به افزایش تقاضا برای منابع آب و سهم حدود 70 درصدی بخش کشاورزی از مصرف آب کشور، استفاده از سامانههای نوین آبیاری بهمنظور کاهش تلفات و ارتقای راندمان، ضرورتی اجتنابناپذیر است. هدف این پژوهش، مقایسه تلفات تبخیر و بادبردگی و ارزیابی عملکرد سه سامانه آبیاری بارانی شامل آبپاش تفنگی، بوم اسپری و سامانه بومیسازیشده توسط بهرهبردار در اراضی تحت پوشش رودخانه مرزی ارس در شهرستان پلدشت (استان آذربایجان غربی) است. دادههای موردنیاز از اندازهگیریهای میدانی طی سه نوبت در ماههای تیر، مرداد و شهریور سال ۱۳۹۷ و در سطح ۵۹ هکتار جمعآوری شد. شاخصهای یکنواختی توزیع آب (DU)، ضریب یکنواختی کریستیانسن (CU) و راندمان کاربرد آبیاری (Ea) برای هر سامانه محاسبه و تلفات تبخیر و بادبردگی تعیین گردید. نتایج نشان داد سامانه بوم اسپری با مقادیر میانگین CU=94.7، DU=91.1 و Ea=85.8 درصد، عملکردی مطلوب و یکنواختی بسیار مناسبی در توزیع آب دارد. سامانه آبپاش تفنگی با مقادیر CU=68.7، DU=64.9 و Ea=67.6 درصد، کمترین راندمان و بیشترین تلفات تبخیر و بادبردگی (میانگین 7/22 درصد) را نشان داد. در مقابل، سامانه بومیسازیشده با مقادیر CU=89.9، DU=85.7 و Ea=94.2 درصد و تلفات ناچیز تبخیر و بادبردگی، از راندمان بالایی برخوردار بود. یافتهها بیانگر آن است که استفاده از سامانههای بوم اسپری یا سامانههای اصلاحشده با پخش مستقیم آب بر سطح خاک، ضمن کاهش محسوس تلفات تبخیر و بادبردگی، موجب افزایش راندمان آبیاری در مناطق بادخیز میشود. توسعه این سامانهها میتواند گامی مؤثر در جهت بهرهبرداری پایدار از منابع آب و کاهش هزینههای انرژی و نیروی کار باشدhttps://hws.tabrizu.ac.ir/article_21451_6f32697ee898cae88d8155b16bf699b9.pdfدانشگاه تبریزدانش آب و هیدرولیک3092-611435420251222Application of MIDAS Model in Flood Forecasting (Case Study: Bahramjoo Basin, Lorestan Province)کاربرد مدل رگرسیونی MIDAS در پیشبینی سیلاب (مطالعه موردی: استان لرستان، حوضه بهرامجو)27432168910.22034/hws.2025.66375.1014FAمهدیکماسیدانشیار گروه عمران دانشگاه آیت اله العظمی بروجردی(ره)افسانهعبدلی کولیونددانشگاه آیت اله العظمی بروجردیJournal Article20250315Introduction<br />In recent decades, the increasing frequency and intensity of flood events have become a major concern in water resources management and environmental planning. Floods are among the most destructive natural hazards, causing substantial economic damage, loss of life, and disruption to ecosystems. The challenge of accurately predicting runoff is particularly significant in mountainous watersheds, where complex terrain, heterogeneous precipitation patterns, and rapid hydrological responses increase uncertainty in modeling processes. Seasonal variability of rainfall further complicates the prediction of runoff, making it essential to adopt advanced modeling techniques capable of capturing these dynamics.<br />The Bahramjoo watershed in Lorestan Province represents a typical mountainous basin characterized by seasonal precipitation and considerable variability in hydrological behavior. Traditional time series models often face limitations when dealing with such variability, especially when input data are available at different temporal frequencies. In recent years, data-driven approaches have gained increasing attention due to their flexibility and ability to model complex relationships without requiring detailed physical assumptions. Among these, the Mixed Data Sampling (MIDAS) model has emerged as a promising approach for handling mixed-frequency data, although its application in hydrology remains relatively limited compared to fields such as economics.<br />Objectives<br />The primary objective of this study is to evaluate and compare the performance of three time series models-MIDAS, Autoregressive Distributed Lag (ARDL), and Generalized Autoregressive Conditional Heteroskedasticity (GARCH) in predicting seasonal runoff in the Bahramjoo watershed. Specifically, the study aims to assess the capability of these models in handling mixed-frequency data, improving prediction accuracy, and preserving the inherent structure of hydrological time series. Another key objective is to investigate whether the MIDAS model can provide a methodological advantage over conventional models by directly incorporating high-frequency precipitation data into seasonal runoff forecasting.<br />Materials and Methods<br />The dataset used in this study consists of seasonal streamflow data and monthly precipitation records collected from hydrometric and meteorological stations within the study area over the period 2006 to 2023. A major challenge in the analysis arises from the mismatch in temporal frequency between the dependent variable (seasonal runoff) and the independent variable (monthly precipitation). To address this issue, three modeling approaches were implemented. In the ARDL and GARCH models, monthly precipitation data were aggregated into seasonal values to match the temporal scale of the runoff data. However, this aggregation process may result in the loss of valuable information embedded in high-frequency data. In contrast, the MIDAS model allows for the direct integration of mixed-frequency variables without the need for aggregation, thereby preserving the original temporal resolution of the data. Each model was calibrated using historical data and evaluated based on statistical performance metrics, including the coefficient of determination (R²) and the root mean square error (RMSE). Additionally, cross-validation techniques were employed to ensure the robustness and reliability of the results. These evaluation criteria provide a comprehensive assessment of the models’ ability to capture both the variability and magnitude of runoff.<br />Results and Discussion<br />The results indicate that all three models are capable of capturing the general trend of seasonal runoff variations in the study area. However, significant differences are observed in their predictive performance. Among the models, the MIDAS approach demonstrates the highest level of accuracy, with an R² value of 0.82 and an RMSE of 0.61 m³/s. In comparison, the ARDL model achieves an R² of 0.66 and an RMSE of 0.93 m³/s, while the GARCH model yields an R² of 0.52 and an RMSE of 0.71 m³/s. The superior performance of the MIDAS model can be attributed to its ability to incorporate high-frequency precipitation data directly into the modeling framework. By avoiding temporal aggregation, the model preserves important information that would otherwise be lost in conventional approaches. Furthermore, the flexible weighting structure of the MIDAS model allows it to assign different levels of importance to lagged values of precipitation, thereby capturing delayed hydrological responses more effectively. The analysis also reveals that the runoff dynamics in the Bahramjoo watershed exhibit relatively stable behavior with characteristics of long-term memory. Runoff tends to increase during wet seasons and decrease during dry periods, reflecting the strong influence of precipitation patterns. The MIDAS model is particularly effective in capturing these seasonal fluctuations due to its ability to model interactions between variables with different temporal frequencies.<br />Overall, the findings highlight the limitations of traditional models such as ARDL and GARCH when applied to mixed-frequency hydrological data. While these models remain useful in certain contexts, their reliance on aggregated data reduces their ability to capture fine-scale temporal variations. In contrast, the MIDAS model provides a more comprehensive representation of the underlying processes, leading to improved predictive performance.<br />Conclusion<br />This study demonstrates that the MIDAS model offers a significant improvement over conventional time series models in predicting seasonal runoff in mountainous watersheds. Its ability to integrate mixed-frequency data without aggregation allows for better preservation of temporal information and enhances model accuracy. The results suggest that MIDAS is a robust and efficient tool for hydrological forecasting, particularly in cases where input data are available at different temporal scales.From a practical perspective, the application of the MIDAS model can contribute to more accurate flood forecasting, improved water resources management, and more effective mitigation of flood-related risks. The findings of this research provide valuable insights for hydrologists, engineers, and decision-makers seeking to enhance predictive capabilities in complex hydrological systems.Future research may focus on extending the application of the MIDAS framework to other regions and temporal scales, as well as integrating it with advanced techniques such as machine learning models. Such efforts could further improve the accuracy and reliability of hydrological predictions and support sustainable water resources management in the face of increasing climate variability.چکیده <br />باتوجهبه اهمیت سیلاب در مدیریت منابع آب، این مطالعه به پیشبینی رواناب فصلی حوضه بهرامجو طی سالهای ۲۰۰۶ تا ۲۰۲۳ میپردازد. برای مدلسازی دادههای رواناب فصلی بهعنوان متغیر وابسته و بارش ماهانه بهعنوان متغیر مستقل از ایستگاههای هواشناسی منطقه جمعآوری شد و با استفاده از سه مدل سری زمانیMIDAS، ARDL و GARCH تحلیل گردید. عملکرد مدلها با آمارههای ارزیابی ضریب تبیین R² و جذر میانگین مربعات خطا RMSE ارزیابی شد. به طور کلی نتایج نشان داد که هرچند سه مدل روند تغییرات رواناب را به درستی پیشبینی نمودند، اما دقت مدل MIDAS بالاتر میباشد. در این راستا مدل MIDAS ، بهترین عملکرد را با ضریب تبیین ۸۲/۰ و RMSE برابر با ۶۱/۰ مترمکعب بر ثانیه داراست. همچنین مدلهای ARDL و GARCH به ترتیب با ضرایب تبیین ۶۶/۰ و ۵۲/۰ و RMSEهای ۹۳/۰ و ۷۱/۰ مترمکعب بر ثانیه عملکرد ضعیفتری را نسبت به مدلMIDAS داشتند. نتایج این پژوهش بیانگر آن است که رواناب حافظه بلندمدت خود را در فراز و فرود سری زمانی حفظ کرده و در فصول پر بارش روند افزایشی و در فصول کمبارش روند کاهشی را داراست. نتیجه کلی بدست آمده پژوهش نشان داد که مدلMIDAS به دلیل توانایی ادغام دادههای با فرکانسهای زمانی متفاوت روزانه، ماهانه و فصلی، توانایی بهتری را در الگویابی و پیشبینی دقیقتر رواناب داشته و در نتیجه در مدیریت و کنترل سیلابها به عنوان راهکار مناسب می تواند مورد بهره برداری قرار گیرد.https://hws.tabrizu.ac.ir/article_21689_1cd7c2937e9dba8b0027dc479d87b79a.pdfدانشگاه تبریزدانش آب و هیدرولیک3092-611435420251222Estimating the Uplift Pressure under Hydraulic Structures with Dual end Cutoff Walls with Finite Element, Regression and Intelligent Approachesتخمین مقدار زیرفشار بالابرنده در زیر سازههای هیدرولیکی با دیوارهای آببند دوگانه انتهایی با روشهای المان محدود، رگرسیونی و هوشمند45582172010.22034/hws.2026.70179.1038FAبهرامنورانیفارغالتحصیل دکتری علوم و مهندسی آب- سازههای آبی، سازمان آب منطقهای آذربایجان شرقی، تبریز، ایران.سولمازکمالی نژادفارغالتحصیل کارشناسی ارشد علوم و مهندسی آب- آبیاری و زهکشی، گروه مهندسی آب، دانشگاه تبریز.فرزینسلماسیاستاد گروه مهندسی آب، دانشگاه تبریز.سمیرارومیانفردانشجوی دکتری عمران-مهندسی و مدیریت منابع آب، سازمان آب منطقهای آذربایجان شرقی، تبریز، ایران.مرتضیانصاریشرکت آب منطقه ای آذربایجان شرقی- تبریز- ایرانJournal Article20251126ABSTRACT <br />The amount of uplift pressure in under hydraulic structures plays a significant role in the dimensions and stability of engineering designs, so its determination and estimation by accurate methods is very important. The purpose of this study is to model and estimate the uplift pressure force at key points under floors with dual end cut-off walls. For this aim, first numerical simulations with finite element method (FEM) using SEEP/W software was performed and after extracting the results, three intelligent models ANN (MLP), ANN (RBF) and GEP and multiple nonlinear regression (MNLR) model were used to estimate the amount of uplift pressure at key points using the parameters affecting it and their performance were evaluated together. Evaluation of the obtained results was performed using statistical criteria R2, RMSE, RE% and KGE as well as graphic diagrams. The results of statistical criteria indicated the superiority of ANN (MLP) model over other approaches. Comparison of violin plots and related indexes showed that the data estimated by the ANN (MLP) model are very closely correlated with the FEM data. It should also be noted that in the this study, a series of nonlinear and explicit regression equations were presented to estimate the amount of uplift pressure at key points with the extracted data, which can be used by design engineers due to its higher accuracy. <br />KEYWORDS <br />Cut-off Walls, Finite Element Method, Hydraulic Structure, Intelligent Model, Uplift Pressure. <br />BACKGROUND AND OBJECTIVES:<br />Uplift pressure exerted beneath hydraulic structures is a critical factor governing their structural stability and design dimensions. The accurate prediction of this force is therefore paramount for safe and economical engineering. While cutoff walls are widely used as an effective countermeasure to control seepage and reduce uplift, the specific configuration of dual end cutoff walls—particularly those of unequal depth—has remained a less explored area in existing literature. Traditional methods, including physical modeling and numerical simulations like the Finite Element Method (FEM), often involve significant computational cost, time, and expertise. This research gap necessitates the development of robust, accurate, and computationally efficient predictive models. The primary objective of this study is to model and estimate the uplift pressure force at key points (designated as C at the upstream point and E at the downstream point) beneath hydraulic structure floors equipped with dual end cutoff walls. To achieve this, the study leverages data from extensive numerical simulations to develop and compare the performance of multiple intelligent and regression models.<br />METHODOLOGY:<br />The research methodology was executed in a systematic, multi-stage process. First, a comprehensive numerical simulation was conducted using the Finite Element Method (FEM) implemented in SEEP/W software (part of the Geo-Studio package). A total of 90 numerical models were developed, encompassing various configurations of dual cutoff walls, including both equal-depth (30 models) and unequal-depth (60 models) scenarios. The influential dimensionless parameters considered were the ratio of floor width to foundation depth (B/D), the ratio of floor width to downstream cutoff depth (B/d₂), and the ratio of upstream to downstream cutoff depths (d₁/d₂). The model was validated against established analytical solutions, confirming its high accuracy.<br />Subsequently, the dataset generated from the FEM analysis (90 data points) was utilized to develop and train four distinct predictive models:<br />1. Intelligent Models:<br />• Artificial Neural Network - Multi-Layer Perceptron (ANN-MLP)<br />• Artificial Neural Network - Radial Basis Function (ANN-RBF)<br />• Gene Expression Programming (GEP)<br />2. Regression Model:<br />• Multiple Non-Linear Regression (MNLR)<br />For all models, 70% of the data (63 points) was used for training, and the remaining 30% (27 points) was used for testing. The models were designed to predict the percentage of uplift pressure at the key points (PC% and PE%) based on the three input parameters. The performance of each model was evaluated using a suite of statistical metrics, including the Coefficient of Determination (R²), Root Mean Square Error (RMSE), Relative Error Percentage (RE%), and Kling-Gupta Efficiency (KGE), supplemented by graphical analyses such as scatter plots, violin plots, and density diagrams.<br />FINDINGS:<br />The findings of this study provide significant insights into both the physical phenomenon and the performance of the predictive models:<br />• Numerical Simulation Results: The FEM analysis successfully demonstrated the impact of varying cut-off wall configurations on seepage patterns and uplift pressure. For instance, increasing the B/d₂ ratio led to a rise in PC% (at C-key point) and a concurrent decrease in PE% (at E-key point). The study also produced a set of explicit, high-accuracy MNLR equations for directly estimating PC% and PE%, which are valuable for practical engineering design.<br />• Model Performance Comparison: The evaluation of the predictive models revealed a clear ranking in performance. The ANN-MLP model consistently outperformed all other approaches, achieving near-perfect agreement with the FEM data.<br />• For the test phase, the ANN-MLP model yielded exceptional statistical results: For PE%, R²=0.997, RMSE=0.223%, RE=0.069%, KGE=0.997. For PC%, R²=0.999, RMSE=0.015%, RE=0.184%, KGE=0.997.<br />• The relative error (RE%) for the superior ANN-MLP model was confined within an impressive range of less than ±2%.<br />• Graphical analyses, particularly the violin and density plots, visually confirmed that the data estimated by the ANN-MLP model closely matched the distribution and statistics of the original FEM data.<br />• The overall ranking of models based on a comprehensive scoring system was: 1. ANN-MLP, 2. ANN-RBF, 3. GEP, and 4. MNLR for key point E, and a similar order for key point C, affirming the superiority of the ANN-MLP approach.<br />CONCLUSION:<br />This study successfully demonstrates the application of intelligent computing techniques in geotechnical and hydraulic engineering. The research conclusively establishes that the ANN-MLP model is a highly superior, reliable, and accurate tool for estimating uplift pressure under hydraulic structures with complex dual cutoff wall configurations. Its performance surpasses that of other intelligent models (ANN-RBF, GEP) and regression (MNLR) methods. Furthermore, the study provides practicing engineers with two practical tools: a set of explicit MNLR equations for quick estimations and a highly precise ANN-MLP model for critical design scenarios. The methodologies and findings are directly applicable to the design and safety assessment of hydraulic infrastructures, enabling more efficient and risk-mitigated engineering solutions. Future work could focus on integrating a wider range of soil properties and structural geometries to further generalize the developed models.مقدار زیرفشار بالابرنده در زیر سازههای هیدرولیکی نقش بسزای در ابعاد و پایداری طرحهای مهندسی دارد، لذا تعیین و تخمین آن با روشهای دقیق بسیار حائز اهمیت میباشد. هدف از این تحقیق، مدلسازی و تخمین نیروی زیرفشار بالابرنده در نقاط کلیدی در زیر کف بندهایی با دو دیوار آببند انتهایی میباشد. برای این منظور ابتدا شبیهسازی عددی با روش المان محدود (FEM) و با به کارگیری نرمافزارSEEP/W صورت گرفت و پس از استخراج نتایج، از سه مدل هوشمند ANN(MLP)، ANN(RBF) و GEP و مدل رگرسیونی چندگانه غیرخطی (MNLR) در تخمین مقدار زیرفشار بالابرنده در نقاط کلیدی با استفاده از پارمترهای موثر بر آن استفاده شد و عملکرد آنها با یکدیگر مورد بررسی قرارگرفت. ارزیابی نتایج بهدستآمده با استفاده از معیارهای آماری R2، RMSE، RE% و KGE و همچنین نمودارهای گرافیکی انجام گردید. نتایج شاخصهای آماری، برتری مدل ANN(MLP) نسبت به سایر روشها را نشان داد. مقایسه نمودارهای ویولنی دادهها و شاخصهای مربوط به آن نشان داد که دادههای تخمین زده شده به وسیله مدل هوشمند ANN(MLP) با دادههای حاصل از FEM تطابق بسیار نزدیکی را داراست. همچنین لازم به ذکر است، در تحقیق حاضر یکسری روابط رگرسیونی غیرخطی و صریحی نیز برای تخمین مقدار زیرفشار بالابرنده در نقاطکلیدی با دادههای استخراج شده ارائه گردید که به دلیل داشتن دقت بالاتر و مطلوب (RE% < 2 و R2 > 0.95) میتواند مورد استفاده مهندسان طراح قرار گیرد.https://hws.tabrizu.ac.ir/article_21720_7a151199893a92d8ae15d90fdf317162.pdfدانشگاه تبریزدانش آب و هیدرولیک3092-611435420251222Investigation of the effects of water suspended load on soil hydraulic characteristics in different soil texturesبررسی اثرات گلآلودگی آب بر ویژگیهای هیدرولیکی خاک در خاکهای با بافت مختلف60722187710.22034/hws.2026.70535.1040FAعلی رضاواعظیبخش مهندسی حفاظت آب و خاک گروه علوم و مهندسی خاک دانشگاه زنجانمهدیهعسگری2-، فارغالتحصیل کارشناسی ارشد – گروه علوم خاک- دانشگاه زنجانJournal Article20251207Background and Objectives <br />Infiltration rate is the rate at which water enters into the soil. It affects the water supply needed for plants and the recharge of groundwater. This soil hydraulic properties can be affected by the soil physicochemical characteristics such as particle size distribution, organic matter, structure and porosity, and management practices (grazing, traffic, tillage etc.). Along with, the rate of water infiltration into the soil can be affected by water characteristics such as hydraulic head and concentration of muddy water. Deposition of suspended load in the soil’s pores blocks the soil pathways for water movement. In various studies that had been done in the flood spreading areas, the researchers have found that soil hydraulic characteristics varies remarkably after flood spreading. Although there is a lot of information on the effects of flood spreading on the soil infiltration rate, little information is available on the effects of concentration of muddy water on water infiltration process. Therefore, this study was conducted to determine effects of different concentrations of muddy water on the soil hydraulic characteristics in different soil textures.<br /><br />Materials and Methods<br />A field study was designed in three areas with different soil textures (sandy loam, silt loam and clay loam) with six concentrations of muddy water consist of zero (clear water), 10, 100, 1000, 10000 and 100000 mg lit-1. Water infiltration rate was measured using small rings with 32-cm in diameter in eighteen points of each land (six treatments at three replications) with 2-m intervals. In total, fifty four field experiments were done using the ring infiltrometer in three areas. Initial infiltration rate and final infiltration rate was calculated for each muddy water concentration using the loss of water head (cm) per unit of time during infiltration process (hours). Soil samples were taken from soil surface (0-30 cm depth) and various physicochemical properties consist of particle size distribution, bulk density, organic matter content and structure stability were determined in the lab. The analysis of variance was done for determining independent effects of two factors (soil type and muddy water concentration) and their interactions on the initial and final infiltration rate using the Tukey’s test. Statistical significant level was considered to be more than 95% (p< 0.05). <br /><br />Results and Discussion<br />Based on the results, the highest initial and final infiltration rate of the soils occurred at zero muddy water concentration (clear water). The highest initial infiltration rate and final infiltration rate was in sandy loam (91.2 cm h-1 and .6 cm h-1, respectively), while the lowest values were observed in clay loam (58.8 cm h-1 and 5.7 cm h-1, respectively). A large difference was among the soils in final infiltration rate (35 %) as compared with initial infiltration rate (11 %). Higher infiltration rate of sandy loam under muddy water concentration is associated with higher macrospore percentage as well as hydraulic conductivity. Initial infiltration rate under muddy water concentrations was significantly affected by soil texture (p< 0.001), muddy water concentration (p< 0.001) and their interaction (p< 0.01). Initial infiltration rate in the soils decreased considerably with increasing muddy water concentration in all soils. The lowest effect of muddy water concentration was in sandy loam, while the highest difference was observed in clay loam. There was no similar decreasing trend in initial infiltration rate with increasing muddy water concentration in the soils. This result showed that there is significant interaction between soil type and muddy water concentration in initial infiltration rate. A large decline in initial infiltration rate (20%) in sandy loam was at 1000 mg lit-1 muddy water concentration, whereas the loss of initial infiltration rate in clay loam was at 100 mg lit-1 muddy water concentration (55%). Also, significant differences were found in final infiltration rate in the soil textures (p< 0.001) and muddy water concentration (p< 0.01). Nevertheless, there wasn’t significant interaction between the two factors in final infiltration rate. A large decline in final infiltration rate in sandy loam and clay loam was at 10000 mg lit-1 muddy water concentration (27%) and 100 mg lit-1 (26%), respectively. <br /><br />Conclusion<br />The results indicated that soil hydraulic characteristics (initial and final infiltration rate) are significantly affected by both soil texture and muddy water concentration. Soil type is an important factor determining the effect of muddy water concentration on initial infiltration rate, while the effect of muddy water concentration on final infiltration rate in all soils is relatively similar. This study revealed that effect of muddy water concentration on the loss of initial water infiltration rate is more than final infiltration rate. Initial infiltration rate in a fine textured soil such clay loam is more susceptible to muddy water concentration as compared to a coarse textured soil (sandy loam). This research showed that the flood spreading to recharge of groundwater in fine-textured soils is limited and is only possible at very lower muddy water concentration.ویژگیهای هیدرولیکی خاک در زمینهای کشاورزی و عرصههای پخش سیلاب میتواند تحت تأثیر درجه گلآلودگی آب قرار گیرد. اگرچه اطلاعات در زمینه شدت نفوذ آب به خاک موجود است اما اطلاعات در زمینه نقش گلآلودگی آب بر ویژگیهای هیدرولیکی خاک وجود ندارد. از این رو این مطالعه به صورت مزرعهای با هدف تعیین تغییرات شدت نفوذ آب تحت تأثیر گلآلودگی آب در خاکهای مختلف انجام گرفت. برای این منظور آزمایش در سه زمین با بافت خاک مختلف (سیلتی لوم، لوم رسی و لومی شنی) در شش غلظت گلآلودگی آب (غلظتهای صفر، 10، 100، 1000، 10000 و 100000 میلیگرم بر لیتر) به صورت فاکتوریل در قالب طرح کاملاً تصادفی با سه تکرار انجام شد. شدت نفوذ آب به خاک در 36 واحد آزمایشی در بازه زمانی مختلف با استفاده از استوانه دوگانه اندازهگیری شد. بر اساس نتایج، شدت نفوذ اولیه و نهایی آب در خاکها تحت تأثیر معنیدار درجه گلآلودگی آب (001/0>p) قرار گرفت. با این وجود اثرات گلآلودگی آب بر افت شدت نفوذ نهایی آب در خاکها کمتر از تأثیر آن بر افت شدت نفوذ اولیه آب بود. اثرات گل-آلودگی آب بر شدت نفوذ اولیه در خاکهای مختلف بسیار متفاوت بود و بیشترین افت شدت نفوذ اولیه آب در خاک لوم رسی رخ داد. در این خاک حتی در غلظتهای بسیار پایین گلآلودگی آب (100 میلیگرم بر لیتر) افت شدیدی در شدت نفوذ اولیه آب (55 درصد) وجود داشت در حالی که در خاک شنی در غلظتهای بالاتر گلآلودگی آب (1000 میلی-گرم بر لیتر) افت کمتری (21 درصد) رخ داد.https://hws.tabrizu.ac.ir/article_21877_94b4ba622ccfc012dd1e5488b142e223.pdfدانشگاه تبریزدانش آب و هیدرولیک3092-611435420251222Evaluation of Surface Irrigation Management Scenarios and Their Impacts on System Performance Indicators Using SIRMOD: A Case Study of Kabutarabad, Isfahanارزیابی سناریوهای مدیریت آبیاری سطحی و تأثیر آنها بر شاخصهای عملکرد سامانه با استفاده از SIRMOD مطالعه موردی کبوترآباد، اصفهان73902187810.22034/hws.2026.71586.1047FAبیژننظریدانشیار گروه مهندسی آبیاری و آبادانی، دانشگاه تهرانمرتضیکمالیگروه مهندسی آبیاری و آبادانی، پردیس کشاورزی و منابع طبیعی، دانشگاه تهران، کرج، ایرانعلیقدمی فیروزآبادیمرکز تحقیقات و آموزش کشاورزی و منابع طبیعی استان همدان، سازمان تحقیقات، آموزش و ترویج کشاورزی، همدان، ایرانJournal Article20260218Introduction<br />Surface irrigation remains one of the most widely used irrigation methods in many developing countries. However, its relatively low performance, primarily caused by deep percolation losses and tailwater runoff, necessitates improved management strategies to enhance water productivity. In regions facing increasing water scarcity, climate variability, and recurrent droughts, optimizing surface irrigation systems has become a critical priority for sustainable agricultural production. Furrow irrigation, as a common surface irrigation method, can achieve acceptable performance when properly designed and managed. Key operational parameters such as inflow discharge, furrow length, and time of cutoff strongly influence infiltration dynamics, advance and recession behavior, and ultimately irrigation efficiency. However, field based evaluation of these parameters is often costly, time consuming, and operationally constrained. Consequently, simulation models such as SIRMOD provide a practical and reliable tool for analyzing hydraulic processes and evaluating management scenarios without extensive field experimentation. SIRMOD incorporates hydrodynamic, zero inertia, and kinematic wave approaches to simulate flow and infiltration processes and has been widely validated for furrow irrigation systems. Despite numerous studies employing SIRMOD, most have examined the effect of input variables in isolation, whereas real-world field conditions involve simultaneous changes in multiple parameters. Understanding the combined influence of inflow discharge, time of cutoff, and furrow length on irrigation performance indicators, including application efficiency (Ea), irrigation requirement efficiency (Er), deep percolation ratio (DPR), and tail water ratio (TWR), is therefore essential for identifying optimal management strategies. This study aims to evaluate the simultaneous effects of these parameters using SIRMOD and to determine the most effective combinations for improving water use efficiency under field conditions.<br />Materials and Methods<br />The study utilized field data from the Kabutarabad Research Station in Isfahan, Iran, previously reported by Salemi et al. (2022). Soil physical properties, hydraulic characteristics, and furrow geometry were employed as model inputs. The soil texture across the 0–60 cm depth was classified as silty clay loam, with bulk density ranging from 1.34 to 1.41 g/cm³ and field capacity between 34% and 36% (vol.). The baseline furrow characteristics included a length of 120 m, width of 0.6 m, slope of 0.002 m/m, and inflow discharge of 1.5 L/s. Infiltration parameters (K, a, f0) were incorporated based on the Kostiakov–Lewis equation. The hydrodynamic model of SIRMOD, which demonstrated the highest accuracy in predicting advance and recession times in the reference study, was selected for simulations. To assess sensitivity and performance, three key management variables of discharge (Q), cutoff time (Tco), and furrow length (L) were each increased and decreased by 20% relative to their baseline values. This yielded 26 combined scenarios in addition to the reference condition. For each scenario, SIRMOD simulated infiltration, runoff, and water distribution along the furrow. Performance indicators were calculated using standard equations: application efficiency (Ea); defined as the ratio of stored water to applied water; irrigation requirement efficiency (Er), defined as the ratio of stored water to soil moisture deficit; deep percolation ratio (DPR), defined as the ratio of deep percolation to applied water; and tailwater rati (TWR), defined as the ratio of runoff to applied water. Model accuracy was evaluated by comparing simulated and measured infiltration and runoff volumes. All simulations were performed under identical soil and hydraulic conditions to isolate the effects of management parameters.<br />Results and Discussion<br />Model validation demonstrated strong agreement between measured and simulated values, with relative errors of 6.55% for runoff, 2.22% for infiltrated water, and 0.68% for advance time, thereby confirming the suitability of the hydrodynamic model for simulating furrow irrigation processes. Scenario analysis revealed that reducing inflow discharge significantly decreased deep percolation ratio (DPR) and tailwater ratio (TWR) while increasing application efficiency (Ea), indicating improved water application uniformity and reduced losses. Conversely, increasing discharge led to higher runoff and deep percolation, reducing overall efficiency. Variations in furrow length showed that longer furrows reduced TWR and increased Ea due to extended opportunity time at downstream sections, whereas shorter furrows increased runoff and diminished efficiency. Among all parameters, Ea and TWR exhibited the greatest sensitivity to furrow length, while Er and DPR were most responsive to cutoff time. Cutoff time exerted the strongest influence on DPR and irrigation requirement efficiency (Er). Shortening the cutoff time minimized deep percolation and increased Ea; however, it reduced Er due to insufficient soil moisture replenishment in downstream portions of the furrow. In contrast, extending the cutoff time substantially increased DPR, indicating excessive infiltration beyond the root zone. The scenario combining reduced discharge, reduced cutoff time, and increased furrow length produced the highest Ea (86.2%) and lowest TWR (13.8%). Conversely, the highest DPR (95.8%) occurred when discharge was held constant while both furrow length and cutoff time were increased. Collectively, these findings underscore the nonlinear and interactive effects of management variables on irrigation performance, highlighting the necessity of integrated, multi‑parameter optimization strategies for improving water use efficiency in surface irrigation systems..<br />Conclusion<br />The study demonstrates that effective optimization of furrow irrigation performance cannot be achieved through isolated adjustments of individual management parameters; rather, it necessitates the simultaneous consideration of inflow discharge, cutoff time, and furrow length. The results clearly indicate that reducing inflow discharge and cutoff time while increasing furrow length can substantially improve application efficiency (Ea) and significantly reduce tailwater ratio (TWR). This improvement is primarily attributed to enhanced opportunity time distribution along the furrow, which promotes a more uniform infiltration pattern and minimizes both runoff and deep percolation losses. However, the findings also reveal important trade-offs among management variables. Excessively short cutoff times may result in insufficient soil moisture replenishment in downstream sections of the furrow, thereby reducing irrigation requirement efficiency and potentially inducing water stress within the root zone. Conversely, prolonged cutoff times markedly increase deep percolation losses, particularly in upstream areas, which in turn diminishes overall system performance and water productivity. These results underscore the critical need to balance applied water depth with crop root-zone moisture requirements in order to avoid both under- and over-irrigation conditions. The application of the SIRMOD simulation model proved to be highly effective for evaluating a wide range of management scenarios and identifying optimal combinations of design and operational parameters without the need for extensive, time-consuming field experiments. Based on the simulation outcomes, the study suggests that farmers and irrigation managers can improve water use efficiency by adopting moderate inflow rates, adjusting cutoff times according to advance and recession behavior, and selecting furrow lengths that provide sufficient opportunity time while minimizing runoff and deep percolation losses. Ultimately, integrating simulation‑based decision support tools like SIRMOD into routine irrigation management offers a cost‑effective and practical pathway toward sustainable water resource utilization in regions facing increasing water scarcity.آبیاری جویچهای به عنوان یکی از رایجترین روشهای آبیاری سطحی، در صورت مدیریت صحیح میتواند تلفات آب را کاهش داده و موجب افزایش راندمان و کارآیی سامانه شود. با وجود پژوهشهای متعدد در زمینه ارزیابی متغیرهای مدیریتی، بررسی اثرات همزمان و اندرکنش این متغیرها بر شاخصهای عملکرد آبیاری کمتر مورد توجه قرار گرفته است. در این پژوهش، از نرمافزار SIRMOD برای شبیهسازی و ارزیابی تأثیر تغییر همزمان سه عامل مدیریتی شامل دبی ورودی، زمان قطع جریان و طول جویچه بر شاخصهای کارآیی آبیاری شامل راندمان کاربرد آب (Ea)، راندمان نیاز آبیاری (Er)، نسبت نفوذ عمقی (DPR) و نسبت رواناب پایاب (TWR) استفاده شد. برای این منظور، هر یک از عوامل ورودی به میزان ۲۰ درصد نسبت به مقدار اولیه افزایش یا کاهش یافت و مدل در قالب سناریوهای مختلف اجرا و نتایج مقایسه شد. یافتهها نشان داد بالاترین مقدار Ea (86/2 درصد) و کمترین مقدار TWR (13/8 درصد) در سناریوی کاهش دبی و زمان قطع جریان و افزایش طول جویچه حاصل شده است. همچنین بیشترین مقدار DPR (95/8 درصد) در سناریوی افزایش طول جویچه و ثابت نگهداشتن دبی و زمان قطع جریان مشاهده شد. تحلیل حساسیت نیز نشان داد که شاخصهای Ea و TWR بهترتیب با میانگین 19/12 و 29/99 درصد بیشترین حساسیت را به طول جویچه دارند. بهطور کلی، نتایج بیانگر آن است که با وجود پیچیدگی مدیریت آبیاری جویچهای، استفاده از مدلهای شبیهساز مانند SIRMOD میتواند بدون نیاز به تغییر زیرساخت، ترکیب بهینهای از پارامترهای مدیریتی را برای افزایش بهرهوری آب در شرایط واقعی مزرعه فراهم کند.https://hws.tabrizu.ac.ir/article_21878_a9ddbb0bb51ea67be25ea64e08162f81.pdf