Abstract : The long-term goal of this research is to provide a capability to extend limited observations of local waves and currents into a larger domain using physics-based models within the littoral zone. It is anticipated that unmanned underwater vehicles (UUVs) and/or underwater autonomous vehicles (UAVs) will be used to provide local observations, and the tool will be able to be run quickly on a laptop. The objectives of the proposed program are to utilize video from UAVs in the littoral region to generate estimates of wave conditions and bathymetry. This would be the first step to more long-term goals, which would require incorporating UUV and in situ observations as well as current estimations. The proposed program will have three parts: (1) develop a ray-trace solver for the wave action balance equation that will allow the prediction of shoaling wave spectra given the local bathymetry and currents, and the assimilation of wave observations inside the domain into the wave field coming into the domain that would reproduce the observations; (2) using the ray-trace solver, generate estimates of wave conditions and bathymetry from video observations of breaking waves; and (3) using the ray-trace solver, generate estimates of wave conditions from video observations of nonbreaking waves (i.e. seaward of the surf zone). So far, the authors have developed the ray-trace solver to the wave action balance equation for shoaling waves and incorporated the sources and sink terms that are in the SWAN model. This required some modifications to the SWAN approach. They have done a comparison between SWAN and this model for a linear beach and a quasi-monochromatic wave and have shown that they are identical (i.e., they can reproduce the SWAN result). They are currently performing a comparison between SWAN and this model for a more realistic beach (the actual bathymetry measured at Duck, NC) and a more realistic wave spectrum (a Pierson-Moskowitz wind-wave spectrum).