Análise ambiental da bacia hidrográfica do Rio São Nicolau (semiárido piauiense) a partir do diagnóstico físico- conservacionista- DFC

Abstract

The basin São Nicolau river is located in north Piauí and crosses the territory in EW flowing to Sambito tributary of the Poti. Encompasses five municipalities of the state covering an area of 5.389.8 km2 and has been intensely busy with many uses generating sometimes degradational effects. The area has great importance about maintenance of water resources in this region besides forming ruiniform landscapes in semiarid area. Given the above, the objective was to make the environmental analysis the basin area especially considering the use of this water resource, and verify which state conservationist she presents and how enables the development of wide variety of activities. For this, we used the Physical Conservation Diagnosis (FCD), proceeding to the literature survey and mapping, geoprocessing and analysis of the parameters that make up the end of the DFC descriptive formula such as: Vegetation Cover Index (VCI), in two periods, Climate Index (CI) Rainfall erosivity (R), soil erodibility (K), Average Slope (DM) and drainage density (DD). The diagnostic result was expressed in the descriptive formula which showed the level of degradation/ preservation in the bowl is located. It is observed that there was a decreased risk of physical degradation in sectors A and B in the time interval between 1989 and 2010, in contrast, there was increased risk in C sector, which presented index of 10,54 in 1989 and 10,92 in 2010. However, the basin that showed the highest rate of degradation was the C sector. The lifting of físicoambientais characteristics together with the results of the analysis of the forms of use and cover the basin contributed to the understanding of the results achieved. Thus, it is observed that the levels of degradation of the basin does not have quite pronounced, even because they have been reduced over the years, however it was not what happened in sector C which had major changes in terms of investments, infrastructure and activities at the same time interval. With this, it is necessary to conduct proper planning throughout the basin, especially in the C sector where the level of degradation was considerably increased in recent years. The shift in the use of resources and application of measures of active management on a larger scale would allow more appropriate management and development facing the sustainability of the region.