Review article

Mini-review on river eutrophication and bottom improvement techniques, with special emphasis on the Nakdong River

Andinet Tekile , Ilho Kim , Jisung Kim


Received June 19, 2014,Revised October 07, 2014, Accepted , Available online April 23, 2015

Volume 27,2015,Pages 113-121

Water quality in rivers is vital to humans and tomaintenance of biotic and ecological integrity. During the FourMajor Rivers restoration of South Korea, remarkable attempts have beenmade to decrease external nutrient loads and moveable weirs were designed to discharge silt that may deposit in pools. However, recently eutrophication of the Nakdong River, which was limited to the lower reaches, is seen to be spreading upstream. The reduction of external nutrient loads to rivers is a long-termgoal that is unlikely to lead to reductions in algal blooms for many years because of the time required to implement effective land management strategies. Itwould therefore be desirable to implement complementary strategies. Regulating the amount of water released is effective at preventing algae blooms in weir pools; so, the relationship between discharge, stratification and bloom formation should be understood in this regard. However, pollutants are likely to accumulate in the riverbed upstream from release points. Thus, to control phosphorus levels, total phosphorus density should be lowered by applying in-river techniques as well. As many ecosystem properties are controlled by multiple processes, simultaneous river bottom improvement techniques, such as combined dissolved oxygen supply and nutrient inactivation, are likely to be effective. The purpose of this review is to present a series of technological approaches that can be used to improve the river bottom area and hence sediment nutrient release, and to illustrate the application of these techniques to the Nakdong River.

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