Detention dams in hydrographic basin with the use of synthetic triangular hydrograms and volume curves

Abstract

This study aimed to apply a flood control proposal, through the use of dams to the runoff of detention for the area of influence of the Itaim stream in Taubaté, Brazil. The basin was divided from upstream to downstream into 4 sections that defined this way, sub- basins A, B, C and D. To calculate the maximum inflow of water into the pond we adopted the maximum rainfall with 100 years of time and return time equal to the concentration time using the PAI‑I-Wu method to obtain the C2 volume flow coefficient using the curve number method. To verify the level of flooding, a synthetic triangular hydrograph methodology and the quota-volume curve were observed. Flow coefficients (C) obtained by the method of curve number of values of 0.24 showed; 0.18; 0.24; 0.32 and 0.34, respectively, for the Itaim basin and sub basins A, B, C and D. These values are lower than those recommended by DAEE SP. Flood areas and levels were assigned and the result showed that the bridge over the Itaim stream would be flooded from the leaf 0.5 meters of a maximum precipitation of 100 years. On the other hand, in the construction of dams (A, B, C and D) at the edge of the sub-basins, flows would be contained, and the bridge on the highway would have a difference of about 1.80 meters above the D of water. These results reflect the buffer capacity of the flood of buses, because the flows diminish with the adoption of these practices.