use dynamic of Luís Alves Watershed a Sub Basin of Itajai, Santa Catarina State

Abstract

This study, had the objectives to analyse the land use dynamic of Luís Alves watershed through the years 1956, 1978 e 2000. The Luís Alves watershed is the smallest of the Itajaí Valley seven sub-basins, it is located near Itajaí river estuary. Itajaí Valley is the biggest Atlantic shed of Santa Catarina State, has about 16% of the State population, and give about 30% tribute of the State, therefore, there are many industries and agricultural activities. The precipitation is about 1.800mm per year, the yearly medium temperature is about 20 ºC and the relative moistness is about 85%. By the help of the softwares like Microstation Descartes (Microsoft Corporation), Spring (INPE) and ArcView, the 1956 and 1978 air-photographs were scanned, registered e interpreted, and then produced land use maps and tables. There was an increment in the tree cover since 32% in 1956 for about 70% in 2000. The grass fields e agricultural forms were covering in 2000 smaller area than in 1956 (50% in 1956 for 22% in 2000). The reason to this dynamic is related to the abandonment of grazing and agriculture and the seasonality of agricultural activities.