Introduction: The lagoon system of the Ciénaga Grande de Santa Marta (Colombia) (Fig. 1) was exposed to adverse hydrological conditions during the second half of the past century. As a consequence, 56 % of the mangrove forests died. In the Barra Vieja lagoon (Fig. 1, 2), a little water body behind the beach ridge, mangroves perished immediately after the construction of the Barranquilla-Ciénaga Road between 1955 and 1960, due to the interruption of water exchange with the nearby Ciénaga Grande. The construction of two box culverts under the road in 1989 and 1995 renewed the water exchange between the two water bodies. Mangrove regeneration was studied since 1994 by observations in the field and studies of aerial photographs and satellite pictures. The aims of the investigation were to determine the efficiency of the hydraulic works on regeneration, the time necessary for a complete plant recovery and to find out similarities or differences between the original and the new mangroves..
