INTERVEN ES ANTRóPICAS EM CANAIS FLUVIAIS EM áREAS URBANIZADAS: REDE DE DRENAGEM DO IGARAPé CARAN , BOA VISTA - RR

This work aims to evaluate the effects of urbanization on the drainage network of the Caran stream in the Boa Vista city in Roraima state. The study included the basins of the Caran stream, which drains the urban area, and Carrapato stream, located adjacent to this city and has geomorphological characteristics similar to the first stream. The work was supported by the interpretation of satellite images, the identification and mapping of drainage networks before and after urbanization, supported by field visits, as well as the basic survey of the discharge of the two basins. The results showed that urbanization was derived from Boa Vista in a slight increase in the extent of drainage area (2.7km) and a significant reduction of the lake basin Caran stream, represented by the drainage of lakes, with the reduction of these areas 6.77to 3.03km2. It was found that the low gradient portions of the lake drained and the high volume of precipitated during the high season (May-July), determine a low efficiency in the drainage of these environments. It was verified that urbanization and drainage lacustrines environments resulted in altering the hydrology of the Caran stream, which increased the amplitude of annual discharge, with higher flow rates during the wet season and smaller discharges at the top of the dry season.