A three-dimensional numerical model of the coastal plume in an ideal basin for the western Gulf of Maine of USA, based on the observations, was configured to examine the dynamical properties under the spring riverine, tidal, and wind forcing.The purpose of this paper is to reveal possible effects of different factors on the coastal plume.The control run with a sloping bottom mimicking the western Gulf of Maine reproduced a southward advection speed of 14 km/d, rnnsistent with the observed speed of 13.3 km/d.The plume evolutions due to the two typical wind forcing, upwelling favourable (wind from north) and downwelling favourable (wind from south), were simulated to explain the observations during the spring of 1993.A systematic sensitivity study was also conducted on the following themes:model parameters, dynamic processes, and topography effect.