Análise hidrográfica avaliando rede de drenagem brasileira: implicações limnológicas

Abstract

It is well-established that water has a crucial importance to life on Earth. Nearly 70% of the Earth surface is covered by water, being the greatest part of it covered by the oceans. Out of all the water on Earth, 3.46% can be found in continents. However, the numbers concerning the continental water surface of the planet are changeable, once researchers generally do not consider the total surface of smaller water bodies. Therefore, this study aims at estimating the length of the Brazilian hydrographic network, as well as its distribution over 12 Brazilian hydrographic regions, by means of the Shuttle Radar Topographic Mission (SRTM). The study included geoprocessing techniques supported by the Geographic Information Systems (GIS). In addition to an estimated length of 7,325,672 km – correspondent to the sum of all the Brazilian rivers, this work also discriminated the stream order, as proposed by Strahler’s methodology, which casts about for the hierarchy of both rivers and streams. Through this discrimination, it was observed that first order rivers (those which communicate directly with their source) represent 51% of the total length of the rivers and streams inside the Brazilian territory, thus indicating that small rivers are most abundant than large ones.