University of Tehran Press Iranian Journal of Soil and Water Research 2008-479X 57 3 2026 05 22 The Effect of Soil Water Characteristic Curve (SWCC) Parameters on Contaminant Transport in Homogeneous Earth Dams The Effect of Soil Water Characteristic Curve (SWCC) Parameters on Contaminant Transport in Homogeneous Earth Dams 531 547 107244 10.22059/ijswr.2026.409884.670088 FA Seyed Ali Asghari Pari Assistant Professor of Civil Engineering,, Faculty of Engineering, Behbahan, Khatam Al-Anbia University of Technology, 0000-0001-5230-9649 Journal Article 2026 01 20 Contaminant transport in homogeneous earth dams is strongly influenced by the soil's hydraulic parameters, the most important of which is the Soil-Water Characteristic Curve (SWCC). This research was conducted to investigate the impact of five key SWCC parameters—saturated volumetric water content (θₛ), residual volumetric water content (θᵣ), the inverse of the air entry suction parameter (α), the pore size distribution parameter (n), and the shape parameter (m)—on contaminant transport in a homogeneous earth dam. Numerical modeling was performed using Geo-Studio 2024 software and the CTRAN/W module, and the influence of variations in each parameter on breakthrough time, concentration profile, and contaminant penetration depth was analyzed. The results indicated that an increase in θᵣ and a decrease in n significantly reduce the time for the contaminant to reach the downstream side, whereas an increase in α and θₛ has the opposite effect and slows down the transport. Parameter m demonstrated a moderate effect on breakthrough time. Regression analysis also confirmed the high sensitivity of the model to parameters θᵣ, θₛ, and n. This study emphasizes the importance of accurate calibration of SWCC parameters in modeling contaminant transport and assessing pollution risk in earth dams. Contaminant transport in homogeneous earth dams is strongly influenced by the soil's hydraulic parameters, the most important of which is the Soil-Water Characteristic Curve (SWCC). This research was conducted to investigate the impact of five key SWCC parameters—saturated volumetric water content (θₛ), residual volumetric water content (θᵣ), the inverse of the air entry suction parameter (α), the pore size distribution parameter (n), and the shape parameter (m)—on contaminant transport in a homogeneous earth dam. Numerical modeling was performed using Geo-Studio 2024 software and the CTRAN/W module, and the influence of variations in each parameter on breakthrough time, concentration profile, and contaminant penetration depth was analyzed. The results indicated that an increase in θᵣ and a decrease in n significantly reduce the time for the contaminant to reach the downstream side, whereas an increase in α and θₛ has the opposite effect and slows down the transport. Parameter m demonstrated a moderate effect on breakthrough time. Regression analysis also confirmed the high sensitivity of the model to parameters θᵣ, θₛ, and n. This study emphasizes the importance of accurate calibration of SWCC parameters in modeling contaminant transport and assessing pollution risk in earth dams. https://ijswr.ut.ac.ir/article_107244_acc9612d3092b5bf3c8fe8008d350a83.pdf