Anthropic impacts on the morphological and sedimentary processes in the coast of Paraná, in Southern Brazil: past and future perspectives.

Abstract

The anthropization of the coast of Paraná was conducted without considering its effects on the coastal morphology, dynamics, and sedimentary processes; all past and present interventions have been proposed still disregarding these aspects. The dredging of channels to port access at sand bars composing ebb-tidal-deltas, which interrupts longshore drift, and consequently, sand deficit downdrift, can be considered the major impact on coastal dynamics. Moreover, natural and anthropic induced estuary silting represents a problem for navigation activities. A significant impact is caused by the obliteration of foredune ridges and urbanization over the beach dynamic fringe, which originates coastal erosion problems in several sectors in the region. The hard stabilization accelerates the process of sand beach loss; up to now, several beach erosion problems remain unsolved. In most of the cases, retreat occupation to release the beach dynamic fringe seems to be a viable solution, however, no projects considering this strategy have been proposed. Special attention is necessary to prevent interventions that could cause irreversible effects on coastal processes and result in more problems than solutions.