Studi Pemisahan Baseflow Menggunakan Metode Grafis

Abstract

This research was conducted to estimate the baseflow at five watersheds in UPT PSDA Pamekasan (Madura - Eastern part of East Java, Indonesia). The methods used in this research was the graphics methods (Local Minimum Method and Fixed Interval Method) and RDF (Recursive Digital Filters) method (Eckhardt Filter). Methodology consist of: (1) data inventoring, (2) data processing, (3) calibrating and validating, and (4) evaluating of models performances. Daily discharge were used as main input for the baseflow analysis, then each recursive digital filter used to separate the baseflow from the total daily discharge. Furthermore, each algorithm was calibrate using daily discharge data for each year. The mean values of parameters obtained used to separate baseflow for whole period of record. RMSE, scatter plot and FDC used to evaluate the model performance during dry period (Juli to September – with assumtion that there was no rainfall occurred in this period). Calibration was conducted on each watershed with the same technique. Validation was conducted from the watershed complete data (Blega Telok watershed) to others watersheds. The results showed that Fixed Interval Method perform better then others algorithms.