Simulação hidrológica do reservatório do Vacacaí-Mirim/Santa Maria - RS utilizando o sistema IPHSI

Abstract

The growing human activity in the proximity of the rivers, has been accelerating the ground erosion process and consequently the aggradation of this rivers. Particularly in the reservoirs, the aggradation causes the reduction of the storage capacity and also the useful life of this structures. This research shows a assessment of the aggradation effects on the flood routing in the reservoir of Vacacaí-Mirim in Santa Maria/RS. It was used the inflow series to the reservoir, generated by the IPH2 model, the batometrias data accomplished in 1961 and 2001, reservoir levels and flow data. Theses information were insert in the IPHS1 sistem for Windows, to simulate the reservoir s level variation in two differents sceneries 1961 and 2001. The comparison of the observed levels in the reservoir with the simulated for the scenery of 2001, showed a better adjustment in the inundation periods regarding the recessive periods. In these, the calculated levels were very below observed, making necessary a revaluation of the period base flow for an adjustment improvement. The simulated levels in each scenery were very close in flood periods, this result was confirmed of the output hidrograph reservoir in flood events. The output maximum flows of the 2001 scenery were in average 2,28 % larger than 1961 scenery. This difference was too small considering the reduction of 29,45 % in the reservoir storage capacity proved the 2001 batometria. In the recessives periods the results were the expected, presenting 2001 simulated levels smaller than 1961. The research concluded that the reduction of extreme flows deadening capacity founded was small, considering the accentuated aggradation process occurred in the reservoir during its operation. However the application of IPHS1 sistem was valid to simulate the reservoir levels in the described sceneries, being a useful tool of the reservoir s behavior study by the alterations occurred during the years.