University of Qom Civil Infrastructure Researches 2783-140X Articles in Press 2026 02 19 Numerical Analysis and Optimization of Drainage System in Agh-Chay Earth Dam Numerical Analysis and Optimization of Drainage System in Agh-Chay Earth Dam 4215 10.22091/cer.2026.14400.1662 FA Ebrahim Asadi Civil Engineering Department, Shahid Madani University, Tabriz, Iran. 0009-0002-3456-8748 Tohid Omidpour Alavian, Civil Engineering Department,, Maragheh University, Maragheh, Iran. 0000-0003-3130-7876 Mahdi Soltani Sotobadi Civil Engineering Department, Shahid Madani University, Tabriz, Iran. 0009-0000-7228-4119 Farzad Ghafarzadeh Arefi Civil Engineering Department, Shahid Madani University, Tabriz, Iran. 0009-0000-9879-1645 Journal Article 2025 12 03 Earth dams represent critical hydraulic infrastructure for sustainable water resource management, yet seepage-induced issues, accounting for over 35% of failures per ICOLD reports, pose significant risks to stability and longevity. This study employs advanced finite element modeling to numerically analyze the impact of a 10% increase in horizontal and vertical drain dimensions on seepage control in the Agh-Chay earth dam, a 108-m-high clay-core structure in West Azerbaijan, Iran. Utilizing SEEP/W software, a refined mesh of 28,450 quadratic elements was constructed for the maximum cross-section (108 m height, 480 m base width), calibrated against 36 months of instrumentation data achieving an R² of 0.958. Incorporating sensitivity analysis, three-dimensional simulations in PLAXIS 3D, and transient flow assessments under critical scenarios like flooding and heavy rainfall, the framework innovatively integrates hydro-mechanical coupling and uncertainty quantification via Monte Carlo methods to optimize drainage efficiency. Results demonstrate a 22% enhancement in seepage discharge (from 0.018 to 0.022 m³/s), a 0.31% reduction in maximum core pore water pressure (from 668.9 to 666.8 kPa), an 8.57% decrease in exit hydraulic gradient (from 0.35 to 0.32), and a 2.11% improvement in downstream slope factor of safety (from 1.42 to 1.45 via Bishop method). This scalable, data-driven optimization not only bolsters dam safety by mitigating erosion risks by up to 91% but also yields 80% savings in maintenance costs and 20% in operational expenses, offering a novel paradigm for resilient earth dam design in tectonically active regions. Earth dams represent critical hydraulic infrastructure for sustainable water resource management, yet seepage-induced issues, accounting for over 35% of failures per ICOLD reports, pose significant risks to stability and longevity. This study employs advanced finite element modeling to numerically analyze the impact of a 10% increase in horizontal and vertical drain dimensions on seepage control in the Agh-Chay earth dam, a 108-m-high clay-core structure in West Azerbaijan, Iran. Utilizing SEEP/W software, a refined mesh of 28,450 quadratic elements was constructed for the maximum cross-section (108 m height, 480 m base width), calibrated against 36 months of instrumentation data achieving an R² of 0.958. Incorporating sensitivity analysis, three-dimensional simulations in PLAXIS 3D, and transient flow assessments under critical scenarios like flooding and heavy rainfall, the framework innovatively integrates hydro-mechanical coupling and uncertainty quantification via Monte Carlo methods to optimize drainage efficiency. Results demonstrate a 22% enhancement in seepage discharge (from 0.018 to 0.022 m³/s), a 0.31% reduction in maximum core pore water pressure (from 668.9 to 666.8 kPa), an 8.57% decrease in exit hydraulic gradient (from 0.35 to 0.32), and a 2.11% improvement in downstream slope factor of safety (from 1.42 to 1.45 via Bishop method). This scalable, data-driven optimization not only bolsters dam safety by mitigating erosion risks by up to 91% but also yields 80% savings in maintenance costs and 20% in operational expenses, offering a novel paradigm for resilient earth dam design in tectonically active regions.