Análise morfométrica dos afluentes principais da bacia hidrográfica do rio Uruguai e sua influência nas enchentes na cidade de Itaqui - RS

Abstract

This work aimed to study the basin of the Uruguay River and its main tributaries, taking into account the three regions defined along the basin (high, medium and medium low Uruguay river), applying the morphometric parameters, analyzing the slope and altitude differences in the defined regions, aiming to identify the influence of those in the floods occurring in urban and riparian areas in the municipality of Itaqui - RS. The delimitation of the basin and sub-basins as well as other processing required to reach the desired results were achieved in ArcGIS 10.2.2 software using Digital Elevation Models SRTM, provided by NASA. Overall, taking into account the Uruguay river basin and its main tributaries, it was found that the study area has little propensity to flooding, or have values of compactness coefficient, circularity index and form factor away from unit. With the hypsometric curve, and analyzing the slope of the Uruguay River, it was observed that the highest peaks are found in the upper Uruguay River region with the predominance of a wavy relief. The region of the middle Rio Uruguay presents medians altitudes compared to the high and medium low Uruguay River and also has predominance of a wavy relief. Soon the medium low river Uruguay has low altitudes compared to sea level and the slope class with higher occurrence is gently rolling. These parameters have influence on the speed of runoff basin, and the flood peaks, infiltration and susceptibility to soil erosion depend on how quickly the runoff occurs on the grounds of the basin. Thus, it was found that the intensification of the occurrence of floods in the city of Itaqui - RS, occur due to the damming of waters both in the river Ibicuí, located downstream from the urban area, and in the river itself Uruguay, taking into account the slope and the altitude of the region.