The Protective Role of a Riparian Vegetation to the Sources of a Rural Watershed

Abstract

A recent review of the Brazilian forest law has suggested the possibility of decrease the riparian buffer width along the banks of waterways. This vegetation can trap solutes which had been deposited in the soil and which would otherwise be carried to the waterways in runoff water. In the current study, we applied the AVSWAT model to the Rio Bonito micro-basin of city of Descalvado, State of São Paulo, Brazil, to verify the amount of nitrogen (N) and phosphorous (P) entering the water resource, and to evaluate the environmental protection provided by the riparian vegetation zones. Our results demonstrate this protection is effective in reducing the amount of nitrogen (N) and phosphorous (P) carried to the river. The scenario produced by the data could be used to diagnose the contamination of this particular watershed and to indicate the measures that should be adopted to ensure the restoration and preservation of riparian vegetation zones.