Water quality in four major rivers has improved in August compared to that in July, and water quality of major water sources maintained the first or second grade.

The water quality of main stream in Han river is generally improved, as BOD level of Paldang Lake in Han River improved from 1.7 mg/L to 1.5mg/L.

Water quality in Nakdong River maintained the second water grade because increased amount of inflowing water improved the water quality. In Goryeong, Namji, Mulgeum at Nakdong watershed, BOD levels decreased by 0.6-1.3 mg/L.

Daechong Lake, the largest water source in central Korea located in Geum River watershed, maintained the first water grade, with BOD 0.9 mg/l. Water quality in upper stream of Geum River, like Okcheon and Daecheong remained the first water grade and BOD levels of lower stream like Cheongwon, Gongju and Buyeo also decreased by 0.3-0.6 mg/L.

In Yeongsan River watershed, the water quality of the upper stream, Damyang, maintained the same level(0.7mg/L). BOD levels of other areas decreased by 0.3-1.8 mg/L.

Juam Lake in Seomjin river maintained fairly good water quality as BOD 0.8 mg/L