Morphometric and pluviometric caracterization of the Manso river watershed – MT

Abstract

Watershed management is an important tool for the maintenance of water resource quality and quantity, and the knowledge of physiographic characteristics is basic to the watershed management. The objective of the present paper is to conduct a morphometric characterization of the Manso River watershed, located inside the municapilities of Chapada dos Guimarães and Rosário Oeste Cities, in the Mato Grosso State, as well as to estimate the basin’s mean precipitation with different methods. Initially, a Digital Elevation Model (DEM) was interpolated from plani-altimetric informations extracted from the IBGE topographic map, in the scale of 1:100.000, using the Tin module of the ArcView GIS-software. Based on the DEM, morphometric parameters of the basin were calculated. The drainage area was found to be 10,793.11 km² and the watershed perimeter about 532.66 km. The compactness coefficient was 1.43, the shape factor 0.21 and the circularity index 0.48, characterizing a watershed with an elongated shape. The drainage density was found to be 0.46 km/km². The annual mean rainfall was determined to be 1526 mm using the arithmetic mean method and 1482 mm applying the Thiessen method. The elongated shape of drainage-basin means that the rainfall on the watershed is concentrated in different points, and it is therefore unlikely to have flood. The elongated form of the watershed indicates that the precipitation falls little concentrated, and is and it is therefore unlikely to suffer floods. Keywords: morphometry, drainage-basin, precipitation.