A theoretical model, and experimental simulations in a wave tank, will be constructed and applied to the problem of wave run-up and damage on breakwaters. A prior numerical model developed by this investigator will be extended to include the effect of porosity in the medium beneath the rubble material which forms the armor of the breakwater. Further, the incident train of waves will be generalized to be irregular rather than periodic. Wave run-up statistics and reflected waves, as well as damage and breakwater profile changes will be determined.