The Nakdong river being used as a drinking source has been significantly contaminated due to the increase of a significant rainfall by a climate change and the nonpoint source by an active land use as well as the inflow of properly untreated wastewater into the river. The objective of this study is to investigate a sustainable technologies for the improvement of the river water quality through mass loading management. In this study, the data obtained from the previous studies by QUAL2E model and an advanced wastewater treatment system were used to derive an optimal river water management. Based on the predictive result, an inflow increase of water with good quality (1st grade quality) into main stream showed a relative effective for reducing organic level in the down stream. This indicates that the security of water resource by weir play an important role to improve the river water quality. The reduction of contaminants in wastewater by an advanced treatment systems as well as an appropriate treatment of intial runoff from nonpoint source showed more effective than that of the inflow increase into the river in improving the river water quality.