Análise das inundações a partir de atributos hidro-climatológicos e ambientais na bacia hidrográfica do Rio Peixe-PB

Abstract

The river basin of the Peixe, a sub basin of the Alto Piranhas, with a dimension of 3. 443 km2 which gathers 18 municipalities in its lower course, suffers the phenomenon of flooding during the rainy season, causing the flooding of the cities of São João do Rio do Peixe, Sousa, and Aparecida. This research aims to understanding the phenomenon from the relationships of the physical framework and geomorphological studies of a basin shape and the indices that are related to the laws of fluvial geomorphology, as well as the interrelationships between the physical substrate and precipitation through the interactions between watershed and atmospheric systems at synoptic, regional and local scales. The use of GIS software for the collection, modeling and analysis of the data was essential for the objectives of this work. The modeling of the maps using the gvSIG software, Arc GIS, Hidroflow make it possible to achieve the objectives linked to Hydrology and Climatology. The results shows the indices Kc, Kf and Ic, of 1.77, 0.19 and 0.31 respectively which states that the basin is not prone for flooding showing that other variables that causes flooding are present there. The results of observations shows that the climatological atmospheric systems operating in the analyzed event for the year 2008, the ITCZ ​​in conjunction with other systems on a regional scale, one Vortex Cyclonic Higher Level - VCAN or a Squall lines are responsible for the precipitation above climatology of the area. For the rainy pattern of the year (2008) the ITCZ ​​was the main atmospheric system, followed by VCANS DOLs and that coupled with the negative dipole, an ENSO episode of La Niña totaling only from January to May a precipitation above annual climatology. The analysis made by referring to the vegetation NDVI - Normalized Vegetation Index shows that there was considerable reduction in the São João do Rio do Peixe and other areas of the basin, however it should be considered that there was a recovery in other areas especially in the mountains, which allows one to state that flooding can be related to assaults of removal of vegetation in the area of ​​ São João do Rio do Peixe especially with the removal of riparian vegetation. The occupation of urban land in the cities of São João do Rio do Peixe and Sousa shows that floods are related to the occupation of the river channel and as well as interventions in the drainage of small dams, dams on the river bed near the city hinder the flow of a larger volume when the aforementioned events.