Author(s): Bartolomeu, Alexandre Paulo Macundje
Date: 2008
Persistent ID: http://hdl.handle.net/10400.1/841
Origin: Sapientia - Universidade do Algarve
Subject(s): Teses; Engenharia do ambiente; Águas costeiras; Gestão integrada; Erosão; Moçambique; 551.468
Tese mest. , Engenharia do Ambiente, 2008, Universidade do Algarve
Bay of Maputo presents beauty, biodiversity and productivity originating pressure on the coastal resources and speeding up the degradation of the quality in the area. Throughout the last years jibs of shoreline in beaches of Costa do Sol occurred, due to insufficiency in sedimentary supply to the coastal drift. The aim of this study is to determine the evolution of the shoreline and sedimentary transport type verified in Costa do Sol - City of Maputo, in 37 years, in approximately 6 km extension, in the Polana beach to Costa do Sol. Different methods to calculate shoreline evolution rates exist. In this work aerial photograph analysis was used. The results indicate that in this period the phenomena’s of jib was verified. From 1996 to the 2006 the jib rates had been more significant in the two analyzed sectors. The erosive trends is mainly verified in of the Praia da Polana, Miramar, Clube Marítimo, ATCM, Bairro de Triunfo and Costa Sol contributing for the retreat of the shoreline, with a maximum erosion rates of - 2,32 m/year. The average shoreline evolution rates have been calculated between -0.53 and -0.62 m/year for 1969/1996 and 1996/2006 respectively and are within in interval verified in previous studies. The current trend shoreline behaviour, in beaches of Costa do Sol, in general, tends for erosion aggravation towards North. Erosion is related to the lack of sedimentary supply, harnessed for the action dams, the dredging of the Canal de Xefina and the sediment retention at coastal protections, leading to the degradation of the natural structures of coastal protection, mainly to the dune ridge between the dry beach and the Avenida Marginal. The implementation of the Integrated Program for the Coastal Zones (PGIZC) for this coastal area faces political constraints, technician-administrative and of coordination between interested organisms, whose activities have negative consequences for the hydrodynamic conditions of the Bay of Maputo. These constraints could be minimized and/or surpassed by application of management and control instruments: legislation, regulations of the drawn plans of development. The solutions proposed to mitigate the problem of coastal erosion are: rehabilitation of the engineering structural - goynes and revetment, combined with the artificial beach replenishment to locations currently suffering erosion; and protection, rehabilitation and dune grassing. The requalification of the maritime edge, based in plans of territorial management plans and intensification of shares of environmental education was considered necessary for transversal sectors of the society, in particular for the beach users and local population.
