Mudança da cobertura do solo e o coeficiente de escoamento de sub-bacias do Rio das Mortes - MT

Abstract

The study of the flow change of the basin is of extreme importance for an understanding of the differences caused by the different uses of the soil. The intensive agricultural use of the Rio das Mortes basin and availability of data at the national integrated system of hydrological information seek to find a relationship between the change in land use over the last 30 years and the change in the coefficient of outflow of the areas of Study within the basin. It was chosen as a way to study a representative sub-basin of the Upper Rio das Mortes and a subbasin representative of the Lower Rio das Mortes to analyze the variations within the basin. It was observed that the two sub-basins present similar behavior regarding annual precipitation and flow, correlating. The Lower Rio das Mortes sub-basin presented the highest precipitation volume per unit area while the Alto Rio das Mortes sub-basin presented the highest annual volume per unit area. The two sub-basins are exploited for agricultural use. Alto Rio das Mortes has 486 points with outflows granted in November 2017 and 98% for irrigation. In the Lower Rio das Mortes there are 25 flow points granted in November 2017 and 83% for agricultural use (irrigation and animal husbandry). The correlation coefficients showed a strong correlation between the flow coefficient and the agricultural use, also showed a strong correlation between the flow coefficient and the natural vegetation. While in the Upper Rio das Mortes, a higher vegetation rate provides a reduction in the coefficient of flow, in the Lower Rio das Mortes a higher vegetation rate provides an increase in the flow coefficient of the sub-basin. In the two sub-basins the flow coefficient shows a strong negative correlation with the agricultural use.