Understanding of the groundwater (GW)-surface water (SW) interaction is essential for the both qualitative and quantitative determination of the exchanging flux between them. The commonly used conductance-based approach, which linearly relates the flux with the streambed conductance, avoids the inclusion of aquifer properties in the flux quantification. In this approach, aquifer properties are solely represented by a hydraulic head below the streambed. Applying an analytical approach to a superimposed GW-SW system, this work finds that the exchanging flux rather follows a nonlinear behaviour when aquifer properties are part of flux quantification. The developed approach is found to match the numerical results obtained from synthetic data. The study further provides approaches for simpler quantification of geometrical and hydraulic properties of the streambed and the aquifer.