Modelagem de cotas de cheias a partir de vazões derivadas de hidrogramas unitários instantâneos geomorfológicos. ; Modeling of water levels from stream flows derived from geomorphological instantaneous unit hydrographs.

Given the lack of hydrological and meteorological monitoring in small and mediumsized watersheds and due to the current temporal discretization of the stream flow historical series freely available to the public, studies and development of techniques for estimating direct surface runoff (DSR) hydrographs have been increseangly conducted. Such studies have great relevance for the analysis of stream flows resulting from intense rainfall events. Among these techniques, the Instantaneous Unit Hydrograph (IUH) and the Geomorphological IUH (IUHGEO) theories deserve attention. Clark (CIUH) is a widely used IUH model and several geomorphological approaches have been developed for it by establishing relationships between CIUH’s parameters and watersheds’ physical characteristics. The modified version of the CIUH (ModClark) has been widely applied in order to verify its performance in relation to the discretization of the watersheds in modules. With regard to flood management in watersheds, the combination of hydrological and hydraulic models is of great importance, as it enables simulation of water levels and water surface profiles. In this context, the main objective of this study was to evaluate a tool for estimating water levels originated from extreme rainfall events, combining hydrological modeling – by means of the ModClark based on geomorphological parameters – and hydraulic modeling. The study area comprises the experimental Cadeia river watershed (CRW), an important sub-watershed of the Pelotas river watershed (PRW), which has active hydrological monitoring and is situated in the south of Rio Grande do Sul State. Different rainfall-runoff events were initially selected and the corresponding hyetograhs and hydrographs were then analyzed. The runoff separation and the DSR depth were determined for each event by the Inflection Method and the Numerical Integration, respectively, whereas, effective rainfall hyetographs were derived from the Curve Number (CN) method. The aforementioned dataset was used as input for ...