Baseflow Separation Using the Digital Filter Method: Review and Sensitivity Analysis

Taeuk Kang,Youngkyu Jin,Sangho Lee,Namjoo Lee

doi:10.3390/w14030485

Taeuk Kang, Youngkyu Jin + Show 2 more

Open Access

https://doi.org/10.3390/w14030485

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Journal: Water	Publication Date: Feb 7, 2022
Citations: 9	License type: CC BY 4.0

Affiliation: Pukyong National University, Kyungsung University

Abstract

The baseflow separation method based on a digital filter is a simple method for separating the baseflow from streamflow. Appropriate estimation of filter parameters is required to use the digital filter method for analysis. We carried out sensitivity analysis on four digital filter methods: Lyne–Hollick (LH), Chapman, Chapman and Maxwell (CM), and exponentially weighted moving average (EWMA). Furthermore, appropriate filter parameters were suggested for each method in this study. By applying them to 25 stage stations in the Nakdong River in the Republic of Korea, the four methods were evaluated. The results of the evaluation showed that the Chapman and CM methods had problems separating the baseflow during the dry seasons. The EWMA and LH methods were able to achieve reliable baseflow separation of the outcomes by selecting appropriate the filter parameters. Thus, the EWMA and LH methods can be used easily and reasonably among the digital filter methods that have one filter parameter.

Highlights

Baseflow is the portion of streamflow that contains delayed subsurface flow, and it is generally maintained by groundwater discharge [1]
Baseflow accounts for most of the streamflow during the dry season, which has a crucial impact on the water quality and aquatic ecosystems [2]
There is a necessity for a baseflow separation method that can accurately separate the direct runoff and the baseflow from the measured streamflow data [4]

Summary

Introduction

Baseflow is the portion of streamflow that contains delayed subsurface flow, and it is generally maintained by groundwater discharge [1]. Baseflow can be obtained using mass-balance methods with tracers [5,6,7,8,9]. These methods usually require monitoring tracer concentrations (ions, isotopes, conductivity, etc.) in surface runoff, stream water, and groundwater, and tracers in different basins can perfectly reflect the hydrogeological conditions [10]. These methods are very laborious and expensive, especially for long-term field measurements [9,11]

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