Sands in Moviment – A Morphodynamic Study at Ilha Comprida/SP

Abstract

For every environmental planning or management, understand the natural dynamic that governs the physical attribute of the space is an exigency. This understanding assumes larger importance in coastal areas face the speed of the action of agents that there act. The Ilha Comprida, south coast of São Paulo State (Brazil), with 74 Km of coastline, was defined as study area. That barrier island was formed by glacio-iso-eustatic events. For the study of the geomorphologic evolution of this Island, maps were made in three different scenarios - 1962, 1974 and 1991, being used for these stereoscope equals of aerial photographs in the scale 1:25,000. Thus, starting from the comparison and overlap of the same ones, it can be proven the great morphologic variation presented by the Ilha Comprida. The main verification is increment of area in its northeast extremity, caused by the contribution of sands. The erosive processes are linked to the progress of the coastline in detriment of the shore terrace, but at few points. In the interior margin of the Ilha Comprida the constant joining of “islands” and sandy banks have been the main geomorphologic modification found. The causes of this process, are the great mass of sediments and low energy of the river channels. Key-words: morphodynamic, coastal geomorphology, Ilha Comprida (SP - Brazil) INTR