STWAVE is a steady-state,  finite difference, spectral model based on the wave action balance equation.  STWAVE simulates depth-induced wave refraction and shoaling, current-induced  refraction and shoaling, depth- and steepness-induced wave breaking,  diffraction, wave growth because of wind input, and wave-wave interaction and  white capping that redistribute and dissipate energy in a growing wave field.  The purpose of STWAVE is to provide an easy-to-apply, flexible, and robust model  for nearshore wind-wave growth and propagation. Recent upgrades to the model include wave-current interaction and steepness-induced wave breaking. STWAVE is written by the U.S. Army Corps of Engineers Waterways Experiment Station  (USACE-WES). The method of analysis used by the STWAVE code along with the file formats and input parameters are described in the STWAVE documentation. SMS supports both pre- and post-processing for STWAVE.