A STUDY ON THE WATER EXCHANGE IN MUNDAÚ LAGOON, NORTHEASTERN BRAZIL DURING THE DRY SEASON

Changes in the inlet morphology of choked coastal lagoons often restrict the water exchange with the sea, making them vulnerable to pollution release and eutrophication processes. In this study, the role of tides for the water exchange was investigated in a choked lagoon for critical scenarios during the low river flow season. Both an integrated and spatially distributed approach were employed using Lagrangian tracking of particles. The spring tides were responsible for the most pronounced water exchange and the spatially distributed approach identified different zones with similar water exchange characteristics. The tide action was primarily limited to the southern portion of the lagoon presenting a zone with rapid exchange times, whereas the other parts involved lower exchange and consequently long renewal times making it a more vulnerable area to different types of pollution releases.