Overview

Currently, there are 1,476 water quality monitoring stations in operation throughout the nation; 697 for rivers, 185 for lakes and marshes, 474 for agricultural area, and 120 for other regions. Monitoring categories include 34 items for river, and 35 for lakes and marshes. Especially, there are 49 automatic operating monitoring stations. The water quality is being monitored by measuring 5 common items such as DO, TOC, pH and other optional items including VOC.

Underground water monitoring stations were used to evaluate water quality by measuring 20 items at 2,499 stations throughout the nation twice a year. As a result of the 2007 groundwater quality study, 299(6.3%) did not meet water quality standards. It has improved last year (5.4%), but has been on the rise over the past five years from 3.6% in 2003 to 5.4% in 2004, and 4.8% in 2005 and 6.3% in 2006.

River Water

Korea slightly revised its Green Vision 21 river quality targets during the review period (the share of rivers assigned Class I and II was reduced from 95 to 87%), but these nevertheless remain very ambitious: out of 114 watersheds (rivers and streams located in the four major basins of the Han, Nakdong, Geum and Yongsan), Korea has assigned a Class I (i.e. best) quality objective to 36 catchments and a Class II objective to a further 46 catchments. Of the 49 graded lakes/reservoirs, 26 have been assigned a Class I objective, 16 a Class II objective and 4 a Class III objective. The grading system takes biochemical oxygen demand (BOD) as its key variable, but also considers variables such as pH, suspended solids, dissolved oxygen, total phosphorus and nitrogen, and total e.coli count.

As for the achievement of these targets, the country's surface water quality has unmistakably improved during the review period, even if the eight droughts suffered in various parts of the country since 1993 account for significant year-to-year fluctuations in quality. Still, the distance-to-target remains considerable: overall, more than two-third of classified rivers and streams met the quality objective in 2007. Almost one-fifth of the watersheds in the Han basin (18%) and in the Nakdong (21%) did not meet their targets, and this also was the case in two-fifth of the catchments (41%) in the Geum basins and two-fifth of the watersheds (35%) in the Yongsan. A noteworthy weakness remains the lack of attention paid so far to the role of rivers as aquatic habitat: no biological water standards have been adopted and water managers appear to have little awareness of aquatic species.

The challenge is almost as great for Korea’s lakes, which are mostly artificial reservoirs supplying domestic, industrial and irrigation uses. One positive development is that the important 2005 water quality targets in the four major drinking water supply sources (Paldang, Mulguem, Daechong and Juam reservoirs) were met over the past three years; in the Paldang Reservoir, which is the main water source for the Seoul metropolitan area, some delicate fish and water insects, such as silver fish and planaria that live only in clean water, are being detected. Elsewhere, however, only 3 of the 26 Class I lakes and 4 out of 16 Class II lakes met the standard in 2007. Eutrophication is also a problem: 2 of the 49 graded lakes are classed hypertrophic, 11 are classed as eutrophic (rich in nutrients), 33 are mesotrophic (with medium levels of nutrients) and 3 are almost oligotrophic.

Drinking Water Sources

The challenge is almost as great for Korea's lakes, which are mostly artificial reservoirs supplying domestic, industrial and irrigation uses. One positive development is that the important 2005 water quality targets in the four major drinking water supply sources (Paldang, Mulguem, Daechong and Juam reservoirs) were met over the past three years; in the Paldang Reservoir, which is the main water source for the Seoul metropolitan area, some delicate fish and water insects, such as silver fish and planaria that live only in clean water, are being detected. Elsewhere, however, only 3 of the 26 Class I lakes and 4 out of 16 Class II lakes met the standard in 2007. Eutrophication is also a problem: 2 of the 49 graded lakes are classed hypertrophic, 11 are classed as eutrophic (rich in nutrients), 33 are mesotrophic (with medium levels of nutrients) and 3 are almost oligotrophic.

Rate of achievement of surface water quality objectives (%)

Water quality trends in four major drinking water reservoirs, 1998-2007 (mg/L)

Groundwater

Groundwater represents about 10% of overall abstractions in Korea and 30% of the estimated sustainable yield. The quality of groundwater is better than that of surface waters, even if on average 13% of shallow and 6% of deep aquifer observation wells show below-standard quality (groundwater quality is classified in three grades, depending on whether it is used for domestic, agricultural/fishery or industrial purposes). Abandoned boreholes pose a significant threat of contamination to groundwater: more than 43,000 such boreholes were capped and made safe during the review period. A nationwide search for further abandoned wells continues.

Coastal water

Coastal water quality is also categorized in three classes. About 35% of the coast meets the highest standard, for Class I. About 55% is in Class II and the remaining 10% is in the lowest grade, Class III. “Red tides” of decomposing algae, resulting from nutrient pollution from agricultural and other sources, are also occurring in some coastal waters and impose a considerable economic cost on fisheries and aquaculture. The Ministry of Maritime Affairs and Fisheries has formulated the National Marine Environment Preservation Plan to restore and maintain coastal water quality. Five severely affected areas, including Masan-Chinhae Bay on the south coast and the Incheon-Sihwa area near Seoul, were designated “Specially Managed Seas” under the Marine Pollution Prevention Act in 2000. Four other areas were designated “Environment Preservation Seas” the same year, to preserve their pristine environment.