Automated Methods for Estimating Baseflow from Streamflow Records in a Semi Arid Watershed

Abstract

Understanding of the runoff generation processes is important in understanding the magnitude and dynamics of<br />groundwater discharge. However, these processes continue to be difficult to quantify and conceptualize. In this study,<br />two digital filter based separation modules, the Recursive filtering method (RDF) and a generalization of the<br />recursive digital filter (GRDF) were1991–2002 in the Hableh Roud River at the stream gauge of Bonkuh, Semnan<br />province. A technique for assessing the recession constants of the sub flows based on calibration the average value of<br />the inverse of the value of the inverse of the slope of the linear path in the recession periods of an Ln (q)-time graph<br />is presented. The result show that, the GRDF method gave higher (Baseflow index) BFI values than the RDF method<br />with less variability and the mean baseflow calculated on an annual basis, ranged from 3.27 m3/s to 4.04 m3/s over<br />period of study by RDF and GRDF, respectively. Since the true values of the baseflow index are unknown, it cannot<br />be said, which one of the methods gives the best estimates.