Abordagem distribuída para simulação chuva-vazão em pequenas bacias hidrográficas

Abstract

Urban floods are a constant problem in Brazil, mainly due to inadequate management and planning of rainwater drainage systems. To mitigate such effects, hydraulic works are projected based on precipitation data, which, in turn, are used for flow estimation in hydrological models. The use of empirical models specifically tailored to surface estimates has been frequently used in regions where there is no hydrological information. Recently, hydrological models have been developed that incorporate the spatial variability of the physical characteristics of the river basins. The use of computational tools to optimize the processes of analysis, definition and management of water resources are increasingly common. Generally, these tools use a series of mathematical models and hydrological and hydrogeological simulation. This work analyzes the incorporation of the physical characteristics of a urban water basin from the adaptation of the curve number model and the triangular synthetic unit hydrograph, both proposed by the Natural Resource Conservation Service (NRCS). The incorporated alternatives cover the use of these methodologies in order to simulate the hydrological processes at the pixel level. The proposed model was applied in Arroio Cascata I, located in the city of Porto Alegre - RS, chosen according to the availability of observed precipitation and flow data. The results indicate that the distributed approach has the characteristic of overestimating the peak flows and underestimating the peak times. However, the calibration validated the distributed model, by generating good alternatives for the estimation of surface flow at the pixel level. It presents, on average, its best result when applied to the hydrograph HUjus, together with combinations of 0,05 for the initial losses and 0,45 for the time to peak factor. Not being discarded the results of the simulations carried out by the distributed hydrograph HUexe.