Caracterização física da microbacia hidrográfica do rio Caiabi com vista ao florestamento compensatório

Abstract

This study aimed to survey the physical characteristics and use and occupation of the watershed stream Caiabi and correlate the area to be reforested with the increased volume of water to be retained. For delimitation of watershed was used a digital model of hydrologically consistent elevation, classification of land use and occupation was performed by supervised classification through a Landsat 8 image and data collection in fields using GPS, and the water to be retained by the watershed using the methodology of compensatory forestation for retention of water in watersheds. The watershed in this study presents an area of 439.40 km², with 154.01 km² of forest, 174.01 km² of agriculture and 90.35 km² of pasture. The slope ranges from 0% to 13.59% with an average of 2.27%. Form factor, compactness coefficient and circularity index, respectively, 0.33 (Ff), 2.43 (Kc) and 0.17 (Ic), the watershed shows no tendency to flooding or flooding peaks. The areas of permanent preservation which are in accordance with the new Forest Code (Law nº 12.651/2012) added 9.67 km² and areas that are in conflict use 2.27 km². The watershed loses in excess water that fails to infiltrate 85.58 million m³/year, which needs to 4767.08 hectares (10.85% of the area of the watershed) reforestation to retain the lost volume.