Comparing groundwater recharge and base flow in the Bukmoongol small-forested watershed, Korea

Groundwater recharge and base flow using different investigated methods are simulated in the 15-ha Bukmoongol small-forested watershed located at the southern part of Korea. The WHAT system, PART, RORA, PULSE, BFI, and RAP software are used to estimate groundwater recharge or base flow and base flow index from the measured streamflow. Results show that about 15-31 per cent of annual rainfall might be contributed for base flow. The watershed groundwater recharge proportions are computed to about 10-21 per cent during the wet period and 23-32 per cent for the remainder periods. Mean annual base flow indices vary from 0.25 to 0.76 estimated using different methods. However, the study found out that all methods were significantly correlated with each other. The similarity of various methods is expressed as a weighted relationship provided by the matrix product from the principal component analysis. Overall, the BFI and WHAT software appeared consistent in estimating recharge or base flow, and base flow index under Korea's conditions. The case study recommends the application of different models to other watersheds as well as in low-lying areas where most observation groundwater wells are located with available streamflow data.