In this paper, some recent numerical test results of an innovative treatment of open boundaries are presented. One of popularly adopted techniques of minimizing wave reflections at open boundaries is to use an "absorbing beach", over which wave energy is dissipated. In addition to a kinetic energy based dissipation term traditionally added to the dynamical boundary condition to form an "absorbing beach", a potential energy based term is added, tested and compared with the case of kinetic energy dissipation alone. Our numerical results show that the newly added dissipation mechanism can dissipate energy more effectively over an absorbing beach and consequently result in a much less reflection of wave energy back to the computational domain. KW - Open boundary conditions KW - absorbing beach KW - nonlinear water waves DO - 10.3970/cmes.2001.002.227