Baseflow separation using graphic method of recursive digital filter on Wae Batu Gajah Watershed, Ambon City, Maluku

Abstract

The most commonly used baseflow separation graphics method is the recursive digital filter. Choosing an RDF graphic filter method to estimate the base stream requires a sure accuracy. The application of the RDF graphics method on small island watersheds must take into account the unique hydrological conditions of small island watersheds with a small area of rain catch so that the RDF method approach can be applied. This research aims to analyze graphic methods for the hydrological characteristics of the small island watershed of the Ambon City of Maluku Province. The research method uses five RDF methods: one parameter algorithm, two-parameter algorithm, RDF Lyne & Holick, RDF Chapman, and RDF Eckhard. The results showed that the appropriate filter parameter value for small island watersheds was based on optimal parameters for assessing accuracy. The five RDFs showed that Eckhardt’s filters performed better than one parameter algorithm, two parameters algorithm, Lyne and Hollick algorithm, and Champman algorithm, on a more extensive range of conditions. The optimal value of the filter parameters is relatively uniform for all five filter methods depending on the characteristics of the watershed and somewhat similar hydrological inputs.