Simulation models based on the elliptic mild or steep slope wave equation are frequently used to estimate wave properties needed for the engineering calculations of harbors. To increase the practical applicability of such models, a method is developed to include the effects of rubble mound structures that may be present along the sides of entrance channels into harbors. The results of this method are found to match those of other mathematical models (i.e. parabolic approximation & three-dimensional solution) under appropriate conditions, but they also deviate from results of parabolic approximations in some cases because dissipation can create angular scattering. Comparison with hydraulic model data also shows that this approach is useful for designing pocket wave absorbers that are used to reduce wave heights in entrance channels.