Hydrological Engineering

The current growth of the population, the successive expansion of urban areas and the lack of hydrologic data, mainly in small catchments, have added increasing emphasis on issues related to the control of the risk of flooding and diffuse pollution, specially in urban catchments. However, urban hydrology models (small urban catchments) should be able to handle the rapidly evolving morphology of urbanized areas. Considering the efforts that have been made to overcome the difficulties encountered in predicting hydrological responses in ungauged catchments, this study aims to derive a geomorphological unit hydrograph (GUH) of an urban subcatchment of the Ribeirão das Pedras from the information available in an urban databank (UDB) and compare it with the unit hydrographs (UHs) obtained experimentally from events recorded in the field. The study area covers a sector of the urban stormwater drainage system in the Campus University Professor Zeferino Vaz. In the first stage, is developed a UDB of the drainage area of the network studied from the information obtainable in cadastral maps. From the information available at the UDB and the application of propagation models over surfaces and channels, it is obtained the GUH of the study area. In the second stage is used a Doppler flow meter to collect field data flow. The application of the UDB in modeling allows to explicit description of the production areas and their runoff flow paths along the drainage system, which contributes to the development of morphological approaches in urban hydrology. The results show a good approximation between the modeled GUH and the average UH observed. In some of the events recorded is observed the influence of variability of rainfall intensities and the performance of the previous rain in the results. Possible factors that influence the adherence between the hydrographs are identified. It is noted the importance of using the GUH based on UDB in the study area, as well as in other ungauged catchments.