Impacts of baseflow contribution on the streamflow variability of major river systems in Korea

High streamflow variability is a potential risk factor in river management in Korea because the use of water resources in Korea depends primarily on surface water. In this regard, analysis of streamflow variability is critical for efficient water resources management. Because streamflow variability is mainly influenced by the contributions of direct runoff and baseflow, the relationship between baseflow and streamflow is an important hydrological indicator that reflects river characteristics. Accordingly, this study was conducted to estimate the effect of baseflow on streamflow variability. For this purpose, a number of streamflow variability indices (SVIs), such as the Richard–Baker flashiness index, the coefficient of variation, the ratio of high flow to low flow (Q5:Q95), and the coefficient of flow regime, were calculated for Korea’s major river systems to determine which SVI best reflects the characteristics of Korean rivers. In addition, baseflow separation was performed to calculate the relationship between SVIs and the baseflow index. The results of this study show that the baseflow index is inversely proportional to streamflow variability. In particular, the impact of baseflow on streamflow variability was highest in the Yeongsan–Sumjin River system. These results are valuable information expected to be used in river management to better secure water resources.