Intense coastal sedimentation and erosion in the Cananéia outlet, southern State of São Paulo, Brazil

Abstract

SynopsisThe extreme mobility of submerged sand bars at the mouth of the Cananéia outlet has made safe access diificult to the lagoonal region of Cananéia~ on the southern coast of the State of Sao Paulo. This problem is serious enough to have been treated by various authors over the past thirty years. Erosional and depositional processes in the area are the result of the combined~ very often conflicting action of tidal currents~ waves~ and longshore currents that are active in the dispersal of the sand sediments o Thus~ at the time that processes of accelerated sedimentation occur at the mouth of the outlet~ intensive erosional phenomena act upon neighboring salient f eatures of the coastline~ such as Ponta do Perigo on Ilha do Cardoso and Ponta da Trincheira on Ilha Comprida. Compara tive analysis of aerial photographs taken in 1962 and 1973 and of some bathymetric profiles allowed us to evaluate the evolution of the erosional process on the eastern side of Ilha do Cardoso during this period interval and to determine the growth tendency of the sand bars in the Cananéia outlet. De scriptors: Sedirnent transport , Coa~tal eros i on , Sediment-water interface, Canané i a ou tl e t (S P) . Ouaternary period. Descritore s : Transpor t e de sedirnento, Ernsão das cost a s , InterFac e se di~ent()-ãaua. Barra de Can anéia ( SP ) . Período quaternári o . o CREEKS __ TRENDS OF THE BEACH RIDGES / J~ \. Ó O Ó05 o Cor