versão impressa ISSN 1405-3195
MARTINEZ-MARTINEZ, Sergio I. e CAMPOS-ARANDA, Daniel F.. Algorithms used to estimate physical properties of rural watersheds and their application in the calibration of the rational methods, in hydrological region No. 12 partial (Santiago River). Agrociencia [online]. 2010, vol.44, n.4, pp. 393-408. ISSN 1405-3195.
The hydrological processes that cause floods are very complex, such that their mathematical modeling requires pluviographic and hydrometric information that is generally not available in most watersheds. The records of maximum annual flows are the best data for predicting these events and for calibrating estimation methods that can be applied to similar watersheds, in particular those that have not been gauged. This study comprises processing two types of data. The first type refers to geographic information in the form of digital elevation models (DEM) to determine the watershed divide, watershed area and physical characteristics of its main channel, including its selection. This analysis concludes with the estimation of the concentration time of each of the seven watersheds that were processed. The second type is based on hydrometric, pluviographic and pluviometric information available in the seven watersheds to identify the Rational method runoff coefficient associated with different return periods. With the numerical results the regional flood estimation method was developed for ungauged rural watersheds or those with unreliable records over short periods. The predictions are shown to be quite reliable since its relative error by defect is below 15 %. This method applies the Rational formula estimating the runoff coefficient (CTr) based on regional median calibrated ratios (CTr/C10).
Palavras-chave : GIS; DEM; ArcHydro; Rational method; runoff coefficients; regional flood estimation.