Temporal analysis of the relationship between land use and land morphology in urban areas: drainage basins of Guacuri and Apurus rivers, Billings Reservoir (SP)

Abstract

The objective of this work was to analyze the relationship between land use and land morphology in the Guacuri and Apurus river basins, on the right bank of the Billings Reservoir, located in the metropolitan area of São Paulo. In order to achieve this objective, correlations between morphological parameters (hypsometry, slope, morphological units) and land use were made for the basins from 1962 to 2001. Throughout this period, an increasing number of self-build houses and buildings was observed in risk areas, which are characterized by concave hillside and steep slopes, whereas planned constructions were built in lowslope areas (convex hill tops and saddles). The anthropic activities caused changes in the original morphology (cuts and embankments), which modified the geomorphological dynamics in both surface and subsurface layers, increasing surface flow, exposing to weather agents the material previously protected by vegetation, reducing soil infiltration rates, among others. Based on the correlations, it was possible to identify three successive stages of urban development. The first stage, the “sub-urban period”, was observed in 1962, when the conditions were similar to the original one, with dominant vegetation cover and few changes in terrain morphology. Between 1962 and 1994, the “construction period” was characterized by the predominance of exposed areas. Finally, the third stage, the “developed-urban period” (1994 to 2001), was characterized by a reduction in vegetation cover and exposed areas, which gave rise to an increase in the consolidation of urban sprawl.