Technical note: An operational implementation of recursive digital filter for baseflow separation

Baseflow estimation is of overwhelming importance in hydrological modelling and water resources management. One of the widely used techniques to derive baseflow from measured stream flow is the Recursive Digital Filter (RDF). Yet its application still raises methodological issues related to the determination of its parameters. In this study, we propose a practical and automatic procedure to calibrate the RDF with respect to the measured stream flow. The method operationality and robustness are first demonstrated on three gauging stations in the Ourthe catchment (Belgium). The calibrated parameters compare well with those obtained by a standard graphical approach. Next, the proposed approach is compared to the technique of Conductance Mass Balance (CMB) for two gauging stations in the Hoyoux catchment (Belgium). A fair agreement between the results of the two techniques is obtained, suggesting that the proposed automatic calibration procedure of RDF takes the baseflow separation process to a higher level of practicality and transparency.FloodLan