As a study of deep seawater utilization, application for possible improvement of seawater quality in an enclosed harbor area was examined by a numerical analysis. The effect of direct discharge of deep seawater is compared with that of surface water discharge. Although deep seawater turned out to be more effective than the surface water, rather large discharge at least 100, 000m3/day was required to achieve a significant improvement of water quality. As an another possible improvement of water quality using deep seawater, nutrient absorption by seaweed community in the enclosed area was evaluated.
