Planejamento territorial e águas urbanas em Maceió: o Plano Diretor e a Bacia Hidrográfica do Riacho Reginaldo

Abstract

The theme of this dissertation focuses on the relationship between territorial planning and urban waters. In particular it considers the instruments used to regulate the use and occupation of urban land and the management of urban waters at the scale of the city. The principal objective is to discuss a new interpretation of the treatment of urban waters which associates the issue of urban drainage with the principles of low impact urban development. The empirical object of analysis is the state of the hydrographic basin of the Reginaldo river, which lies totally within the urban area of Maceió, the capital of the State of Alagoas, Brazil. This choice of theme emerged from the premise that the urban hydrographic basin is an important territorial unit for environmental analysis in the process of urban planning, and that understanding the interaction between its components allows one to describe the pressures of the urban environment on the hydrological cycle. The period studied was between 1985 and 2009. During this period two master plans of Maceió were produced. Secondary sources provided the information for an understanding of the socio-environmental and territorial context, with a focus on planning and the management of urban waters in built up areas, and for an understanding of the relationship of urban planning with the provision of water supply and sewerage. It was confirmed that the socio-environmental problems of Brazilian cities are explained, on the one hand, by the segregationist model of Brazilian urbanization and, on the other hand, by the absence of of an effective housing policy for low income groups. As a consequence we have the occupation of environmentally fragile areas, such as slopes and valley bottoms, which has had a direct impact on hydrological processes and, as a consequence, altered them. These alterations are systematically reinforced by the growing impermeabilisation of urban land, which has contributed decisively to the increase in surface run-off, and has, consequentially, affected the conditions of urban drainage. The conclusions, based on an empirical analysis of the hydrographic basin of the Reginaldo river, emphasise the fact that the form in which the occupation of urban land occurred, and the absence of an adequate level of provision of water related services, especially for the disposal of sewerage and the management of solid wastes, are the main pressures which have led to the degradation of that river basin. Furthermore it was noted that in spite of these pressures the institutional responses have not yet recognised the close relationship between urban planning and the management of urban waters at this scale. This therefore points to a close relationship between territorial planning, urban waters, and the elements of water related services. The study demonstrates that in Maceió the hygiene-based focus on matters of urban drainage still predominates, and that the Master Plan, more than 4 years after its approval, was not capable of enforcing changes in the customary local forms of use and occupation of the land, with a view to minimising the impacts of urbanisation on the system of urban drainage of Maceió.