At riverbank filtration sites, groundwater levels of alluvial aquifers near rivers are sensitive to variation in river discharge and pumping quantities. In this study, the groundwater level fluctuation, pumping quantity, and streamflow rate at the site of a riverbank filtration plant, which produces drinking water, in the lower Nakdong River basin, South Korea were interrelated. The relationship between drawdown ratio and river discharge was very strong with a correlation coefficient of 0.96, showing a greater drawdown ratio in the wet season than in the dry season. Autocorrelation and cross-correlation were carried out to characterize groundwater level fluctuation. Autoregressive model analysis of groundwater water level fluctuation led to efficient estimation and prediction of pumping for riverbank filtration in relation to river discharge rates, using simple inputs of river discharge and pumping data, without the need for numerical models that require data regarding several aquifer properties and hydrologic parameters.

Abstract
 1. Introduction
 2. Geological and hydrogeological setting
 3. Methods
 4. Results and Discussion
  4.1. Seasonal trends in stream discharge, groundwater level, and pumping quantity
  4.2. Auto- and cross-correlation analyses
  4.3. Autoregressive analysis
 5. Conclusion
 REFERENCES

• Jae-Yeol Cheong(R&D Institute, Korea Radioactive Waste Agency)
• Se-Yeong Hamm(Department of Geological Sciences, Pusan National University) Corresponding author
• Hyoung-Soo Kim(Department of Renewable Energy, Jungwon University)
• Soo-Hyoung Lee(Korea Institute of Geoscience and Mineral Resources)
• Heung-Jai Park(Department of Environmental Engineering, Inje University)