Estudo da dinâmica da erosão na zona de restauração de mangal no bairro Icidua, Quelimane, província da Zambézia.

Abstract

From antiquity, the man indiscriminately deforests the mangrove for cultivation purposes, aiming at his own sustenance, exposing, in this way, the soil to the destructive action of rain, wind and hydrodynamic action when using it inappropriately. The gradual deterioration of soil results in the loss of the rich soil layer caused by erosion, causing untold damages. This work was carried out in the mangrove reforestation field in Icidua located in Quelimane city, Zambézia province, this area is dominated by semi-diurnal tides, composed of clay soils that contribute to the existence of the species Avicenna Marina. Considering the difficulties faced in that area, the current work focused on studying the erosion dynamics in the reforestation field, evaluate the erosion advance as well as finding out what are the main causes of this erosion. During the research many observers occurred for better development of this work, were used satellite images of 2002 to 2017 provided by Google Earth, equally happened a harvest of data in the study area which lasted 12 hours. We obtained during this campaign data of the absolute current of tides, turbidity, waves and tides information. The results obtained show that in the erosion dynamics station 1 and station 4 had less advance of the coastline, different from station 2 and station 3 that presented a greater advance reaching to exceed the 3 meters chosen for observations. The method used to monitor erosion in this reforestation field of mangrove showed effective having introduced above 90% acceptance in all stations. The area has the maximum speed of currents during the ebb tide that achieves 75cm / s of flow. Stations 1 and 4 are that covered by mangrove it protects this area from erosion, this area will take a lot of time to erode unlike stations 2 and 3 which is not covered by mangrove, the erosion rate will be higher, by the way will take less time to erode as in these areas the erosive processes are intensified leading to greater soil wear.