AvaliaÃÃo ambiental e percepÃÃo dos usuÃrios sobre os efeitos das obras de proteÃÃo de costa nas praias da Casa Caiada (Olinda) e Janga (Paulista)

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

The coastal zones and special the beaches are dynamical and fragile regions in a continuous change. The high population concentration in these areas results in a pressure increment upon natural resources and increased risk of environmental degradation. The coast of the Sate of Pernambuco, is experiencing coastal erosion that has many times being mitigated with the installation of coastal defense structures, as is the case of the beaches of Casa Caiada (Olinda) and Janga (Paulista). Both of these beaches are located along the northern coast of the State of Pernambuco, where series of wave breakers were constructed to contain the erosion process. Costal interventions need to be continuously evaluated and monitored, what also includes surveying the usersâ perceptions. The present work focused on the evaluation of the hydrological, hydrodynamic, sedimentological and of bathing conditions along the beaches of Casa Caiada and Janga after the implantation of coastal defense structures, as well as the infra-structure and security conditions and the profile and perception of the beach users. The in situ survey were carried out in a way to characterize the study areas during raining (June and July/2006) and dry seasons (December/2006 and November/2007). The work included, for both areas, morphobathymetric survey using an ecosounder associated to a GPS system; the obtention of CTD profiles; measurements of the intensity and direction of water currents with a SD30 current meter, besides the collection of water and sediment samples. Hydrologic and hydrodynamic surveys and water sampling for water quality were conducted at 11 stations at Casa Caiada and at 9 stations at Janga with, 30 and 53 sediment sampling sites respectively. Obtained results indicates that the coastal defenses structures installed at the Casa Caiada and Janga beaches contributed to minimize the erosive process, but modified bottom coverage, favoring the deposition of fine sediments particles on the infralittoral, deposition leeward of the wave breakers and of the jetty, as well as the formation of channels were most of the drowning accident occurs. At these beaches, the horizontal and vertical distribution of the variables temperature, salinity and pH were relatively homogeneous. Detected fluctuations being associated to the seasonal cycle (precipitation and wind regimes) that controls the greater or smaller influence of the continental inflows and the tidal regime that propitiates a larger or smaller exchange with the adjacent marine waters. The two studies beaches present low water quality during the raining season, with indices above the limits indicated on the CONAMA resolution 357/05 for saline water of primary contact, but tends to improve significantly during the dry season. The users of the beaches of Casa Caiada and Janga utilize the areas mostly for the practice of exercises and leisure and leaves nearby. At Casa Caiada existent infra-structure, cleaning and security conditions are better. At Janga there is a notorious lack of satisfaction of the usersâ relative cleaning, security and available beach infrastructure

ASSUNTO(S)

environmental evaluation avaliaÃÃo ambiental casa caiada janga janga obras de contenÃÃo usersâ perception percepÃÃo dos usuÃrios casa caiada oceanografia fisica coastal defense structures

ACESSO AO ARTIGO

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