In the past decade, the grouting industry has made significant technological advancements in real-time monitoring of flow rate and pressure of pumped grout, stable grout mix design, and with grout curtain concepts dealing with placement and orientation. While these practices have resulted in improved construction practices in the grouting industry, current design guidelines for grout curtains are still predominately based on qualitative measures such as engineering judgment and experience or are based on proprietary methods. This research focused on the development of quantitative guidelines to evaluate the effectiveness of a grout curtain in porous media using piezometric and hydraulic flow data. In this study, a laboratory-scale physical seepage model was developed to aid in the understanding and development methodology to evaluate the effectiveness of a grout curtain. A new performance parameter was developed based on a normalization scheme that utilized the area of the grout curtain and the area of the improved media. The normalization scheme combined with model-based Lugeon values that correspond to pore pressure and flow rate measurements at different soil unit weights and grout curtain spacings, produced a mathematical equation that can be used to quantify the effectiveness of a grout curtain. This study found a relationship that takes into account soil unit weight, grout curtain spacing and a new performance parameter that can be used to help predict the effectiveness of a grout curtain.