This paper presents an innovative approach integrating the Image Processing Method and the Beer-Lambert Law to study Sea Water Intrusion in riverine systems. Using an experimental setup, this study characterizes the dynamics between saline and fresh waters, providing detailed spatial and temporal salinity distribution analyses. The Beer-Lambert Law is employed to convert image pixel data to accurate concentration measurements, essential for understanding the diffusion and mixing processes of saline wedges. This study not only bridges technological advances with hydrological research but also provides crucial data for water resource management in coastal areas affected by Sea Water Intrusion. The integration of the Image Processing Method and Beer-Lambert Law exemplifies a significant advancement in environmental monitoring, promoting sustainable water resource management in regions vulnerable to saline intrusion. Results showed that the concentration of the salt water is decreased when it flows upstream horizontally. also, the concentration of the saline water is decreased vertically, due to the salt and fresh water mixing.