Land as a sustainable resource in city planning: The use of open spaces and drainage systems to structure environmental and urban needs

Abstract

The lack of open spaces in urban areas, associated with degraded river environments aggravates one of the main problems faced by cities nowadays: flood risk. This study aims to contribute to the sustainable management of cities by recognizing land as an important finite resource and emphasizing the importance of land use planning in designing resilient cities. The combination of an open space system with urban drainage solutions in multifunctional arrangements can provide a safer setting, better able to structure urban growth. This discussion is supported by an assessment framework that comprises historical analysis, mathematical modeling and estimation of the expected annual damage, in a case study applied to the Canal do Mangue (Mangue Channel) watershed in Rio de Janeiro, Brazil. Three scenarios were built to support the analyses. The first scenario refers to the current situation while the second corresponds to an official proposal of the municipal government to mitigate floods. Finally, the third scenario corresponds to a hypothetical alternative historic growth, from the start of the nineteenth century, assuming that urbanization was based on orderly land use planning, driven by the drainage network interacting with the urban open spaces as a planning structure axis. The results indicate that planning land use and urban development in advance while recognizing water dynamics and natural limitations, can produce better responses in terms of avoiding flood damages than adopting mitigation actions after development of water spaces and stressing land resources. The possible structural mitigation measures face limited space constraints. Therefore, the actions represented in Scenario 3 can configure a set of guidelines that can help growing cities to develop more sustainably.