The effect of total maximum daily loads (TMDL) program on water quality improvement in the Geum River basin, Korea

AbstractIn this study, an analysis using nonparametric statistical methods was conducted to assess the effect of Korean total maximum daily load (TMDL) program on the improvement of water quality in the Geum River basin, Korea. The result of analyzing the trend of long-term BOD change from 2003 to 2012 by seasonal Mann–Kendall test showed that there was no significant change (GR-1, GS-1, MH-1) or a trend of increase (GR-2) in “water quality improvement plan area,” whereas a trend of decrease was observed in “implementation plan area” (GR-3, GR-4, GR-5, GS-2, MS-2). The period of TMDL implementation was divided into four time sections, and the BOD in each time section was compared with the others using the Kruskal–Wallis test. Compared with pre-TMDL stage, the effect of water quality improvement did not appear in the early first stage but appeared first in the tributaries, Gap Stream (GS-2) and Miho Stream (MS-2) in the late first stage of TMDL. At the mainstream sites (GR-3, GR-4, GR-5), the effect of wat...