The Cook Inlet Regional Citizens Advisory Committee (CIRCAC) and the Prince William Sound Regional Citizens Advisory Committee (PWSRCAC) have jointly produced an oil spill model that entirely encompasses Cook Inlet as well as Shelikof Straight and a small part of the Gulf of Alaska. The modeled region is approximately 400 Km by 400 Km. Cook Inlet is a resonant basin with tidal ranges in some areas on the order of 10 meters with extensive areas that go dry at low tide and currents in excess of 5 Kts. Because of the large currents and current variations in Cook Inlet it was necessary to place considerable emphasis on a flow model to construct an oil spill model. The model allows the user to specify the location of the oil spill, time, date, duration of the spill as well as other parameters. The model has an interactive graphical interface. To aid in this interactive process, displays of the path and shape of the oil spill are included as well as water velocity, date and time. The user can update wind speed and direction as desired. The model will allow the user to update a spill location if field data becomes available. Other useful features of the model include the location of land impacts, and a trace facility. The trace facility displays a history of the spill trajectory.