A faixa terrestre da zona costeira e os recursos hídricos na Região Hidrográfica do Atlântico Sul, Brasil

Abstract

No Brasil, o Plano Nacional de Gerenciamento Costeiro II delimita a faixa terrestre da zona costeira, utilizando, principalmente, critérios administrativos, os limites municipais. Contaminação das águas costeiras e aumento da intrusão salina são exemplos de problemas que podem surgir quando a delimitação da área de gestão não contempla o funcionamento dos sistemas físicos, como as bacias hidrográficas. Partindo da premissa de que existe uma relação de causa e efeito entre o uso da terra na bacia e a qualidade ambiental costeira, o presente estudo analisa a delimitação da zona costeira terrestre da Região Hidrográfica do Atlântico Sul. A partir do confronto entre a definição federal e a dos estados com os limites da bacia que drena para o oceano, propostas são elaboradas para os estados que apresentam deficiências na integração dos processos físicos com as fronteiras de gestão costeira. Observa-se que os estados, muitas vezes, não utilizam a mesma definição proposta pela esfera federal. Os estados do Rio Grande do Sul, Paraná e São Paulo incluem, de alguma forma, na sua definição de zona costeira terrestre, o critério da bacia de drenagem. Somente o estado de Santa Catarina não o considera, e, além disso, usa uma definição que diminui a delimitação nacional O estado de Santa Catarina deve aprimorar a sua definição. Em primeiro lugar, através da inclusão dos municípios excluídos da definição nacional. Em segundo lugar, por meio da criação de uma zona de influência costeira, que não faz parte da zona costeira propriamente dita, mas que seria uma zona para a integração das políticas ambientais, sobretudo da gestão costeira com os recursos hídricos. O estado do Rio Grande do Sul, apesar de considerar a bacia de drenagem na sua definição de zona costeira, não considera os limites municipais, preconizados pela definição nacional. As definições dos estados do Paraná e de São Paulo estão aceitáveis, considerando suas características físicas. Observa-se a tendência de utilizar definições mais específicas no nível estadual. Contudo, dos estados analisados, não há nenhuma que possa ser extrapolada para os outros estados. Cada estado deve considerar delimitações mais específicas em função das suas particularidades físicas, sobretudo a área da bacia de drenagem costeira.

The Brazilian National Coastal Management Plan II defines the terrestrial stripe of coastal zone using mainly administrative criteria, namely the municipal boundaries. Pollution of coastal waters and increase in saltwater intrusion are examples of problems that may occur when the management boundaries does not consider the physical systems, such as the catchment basin. The hydrographical basin is the area that drains the rainwater to the watercourses, following the geographic and topographic environmental characteristics. Thus, the hydrographical basin can be set as the unit of environmental management. Assuming that there is a cause-effect interaction between the land use in the basin and the coastal environmental quality, this article does an analysis of the terrestrial coastal zone definition in the Brazilian South Atlantic Hydrographical Region. The federal coastal definition is compared with the states definition and with the hydrographical basin that drains directly to the ocean. Then proposals for new coastal zone boundaries are made for the states that have deficiencies in integrating the physical boundaries in the coastal management boundaries. There are conflicts regarding the territorial cuts in the integrated management in Brazil. The water resource policy uses the hydrographical basin as unit; the environmental policy uses the territorial limits of the federal entities (union, states and municipality) and the coastal management uses the Coastal Management National Plan definition and the municipalities as units. In this context, this article aims to propose a manner to find an intersection of these territorial cuts, especially between water resources and the coastal zone. The concept used was that the boundaries of coastal zone can be the basis for the integration of environmental policies. It was noted that states often do not apply the same definition as the federal government The states of Rio Grande do Sul, Paraná and São Paulo somehow include in their coastal zone definition the criterion of drainage basin. Only the state of Santa Catarina does not. Furthermore, it uses a smaller definition than the national one. The Santa Catarina state must improve its coastal definition. Firstly, through the inclusion of municipalities excluded from the national definition, which has in their territory activities of great environmental impact (coal mining). Second, by creating a zone of coastal influence (ZCI), which is not part of the coastal zone itself, but an area for the integration of environmental policies, especially coastal and water resources. The ZCI could be defined based in the physical dynamics of the environmental and the drainage basin. The management strategy of the ZCI will be different from the coastal zone itself. It will not be under the rules of the national coastal management plan, i.e., having a municipal plan of coastal management, but will be an area where the land and water use should considerer the consequences to the coastal zone. Environmental licensing and water permits in the ZCI should observe the cause-effect relation in the coastal zone. The water permits must control the freshwater inflow necessary to the estuarine ecosystems and the natural saltwater intrusion in the estuary. The environmental licensing and the qualitative water permits must be used to maintain a good water quality in the coastal zone. The ZCI could be defined based on the Kjerfve (1987) estuary’s definition – in which the upper estuary is bounded in the tidal penetration. Then, the ZCI would be the area between the upper limit of the estuary and the coastal zone (defined by the National Plan of Coastal Management) Although the state of Rio Grande do Sul observes the catchment basin in its definition, it do not consider the municipality limits, as recommended by the national government. The management process becomes complicated when the instruments of coastal management can be applied only in part of the municipality territory. The Rio Grande do Sul definition should be improved by including the municipality criterion. The intersection between the municipality and the basin criteria should be done by rounding off. The municipalities with an area of more than 50 % inside the coastal drainage basin is included in the coastal zone, and the ones with less than 50% of the area will be not coastal zone. The Paraná and São Paulo coastal zone definitions are considered acceptable as it includes the catchment basin and the municipality criteria. It is observed a tendency to use more specific definitions at the state level. However, in the states analyzed, there is no definition that can be extrapolated to other states. Each state should have a specific definition in terms of their physical peculiarities, especially the size of the coastal catchment. In the states of Rio Grande do Sul, Paraná and São Paulo the integrated coastal and water resources management should be done in the coastal zone, and there is no need for a zone of integration. Outside the coastal zone, the instruments of water resources and environmental management should be applied as usual.