Comparative analysis of hydrological behavior between two sub-basins of Rio das Mortes – MT

Abstract

The present study had as objective to know the hydrological behavior in two sub-basins of the Rio das Mortes, one representing the portion of the Upper Rio das Mortes and another representing the Lower Rio das Mortes and comparing them. Hydrological information was sought in the Hydrological Information System of the National Water Agency, the information was worked in QGIS 2.12 Software and statistical analysis was performed in Microsoft Excel. As the period of availability of hydrological data is different, it was decided to analyze the data from the Upper Rio das Mortes of the last 30 years and compare the data of the last 15 years with the representative sub-basin of the Lower Rio das Mortes. The Lower Rio das Mortes sub-basin presented higher precipitation per unit area while the upper Rio das Mortes sub-basin had the highest annual volume per unit area. A negative trend was identified in the precipitated annual volume over 30 years in the Upper Rio das Mortes, while the Lower Rio das Mortes presented a slight positive trend in the precipitated maximum monthly volumes.The two sub-basins present irrigation as the largest user of water, which is higher in proportion in the Upper Rio das Mortes. The annual flow coefficients in the Upper Rio das Mortes ranged from 0.31 to 0.47 while in the Lower Rio das Mortes subbasin ranged from 0.20 to 0.50. The values of the runoff coefficients are influenced by environmental and social factors.