Year of Publication



Martin School of Public Policy and Administration

Committee Chair

Dr. J. S. Butler

Executive Summary

The Ministry of Environment of the Republic of Korea has been making efforts to improve water quality and the health of the aquatic ecosystems of the inland waters. Establishing water quality standards for point sources and permissible wastewater emission standards to achieve the target environmental standard were part of the efforts. Nevertheless, water quality indexes such as Biochemical Oxygen Demand(BOD) and Chemical Oxygen Demand(COD) has not improved significantly. Also, harmful cyanobacteria blooms have frequently been occurred, which, in particular, has brought people to lose faith in the environmental policy and has created anxiety about drinking water. As the solution, the government introduced the Total Maximum Daily Loads Management(TMDL) System for the major rivers in 2004. In the system, if water quality is worse than a target water quality, the local government should establish a TMDL implementation plan to limit pollution loads into the streams.

In this paper, I use a difference-in-difference approach to investigate whether the implementation plan for TMDL on total phosphorus (TP) was effective in reducing TP concentration. For that, I constructed a balanced panel data from three rivers in Korea from 2004 to 2015. Also, a fixed effects model was employed to handle the unobserved variables. The results show that the TMDL policy has a statistically significant effect on reducing TP concentration. It may be suggested that for the health of people and aquatic ecosystems, the government may need to expand the TMDL implementation plan to all regions where people rely on rivers for their drinking water. Even though water quality of these regions satisfies the target water quality, the TMDL implementation plan might be helpful for preventing cyanobacteria blooms.