SELECTING THE TIME OF CONCENTRATION CONSIDERING GROUNDWATER DEPTH AND RUNOFF COEFFICIENT IN THE ARGENTINIAN PAMPA REGION

Seleção do tempo de concentração considerando profundidade das águas subterrâneas e coeficiente de escoamento na região do pampa argentino

Abstract

The time of concentration (Tc) is one of the most sensitive parameters for calculating the maximum runoff in a basin and plays a key role in the determination of design flows. In this work, the consistency of the equations that make up the analytical methods used to estimate the Tc is evaluated through the contrast of observed events from the application of the graphical method in a plain basin located in the Pampa region, Argentina. The methodology used considers the complexity of the runoff generation process and of the water dynamics of the region taking into account the analysis of the groundwater depth and the runoff coefficient. This study shows that the equations available may generate Tc predictions with errors by up to 95% in plain basins. The results indicated that Ventura’s and Pasini’s equations are suitable to determine Tc under water deficit, while Izzard’s and Kinematic Wave equations are appropriate for saturated conditions of the system.