Decadal and seasonal scale changes of an artificial lake environment after blocking tidal flows in the Yeongsan Estuary region, Korea.
Artificial lakes, initially built in estuaries for positive purposes such as flood prevention and providing irrigation water, have been found to have negative impacts including blocking tidal cycles, disappearance of brackish water zones, sediment increase, water pollution, change of microbial diversity inhabiting patterns, and a decline in fish diversity. In this study, multidisciplinary field studies including physical, chemical, and biological analyses were performed to demonstrate decadal and seasonal scale changes in the ecological environment in Yeongsan Reservoir (YSR), Korea, since the construction of a 4.35 km-long dam in 1981. The results of the study show that the volume of sediment accumulated in YSR was 75.2 million m(3) since the dam was constructed, resulting in a 33.6% reduction of the total water storage capacity. Also, water quality in YSR was affected by complex physico-chemical and hydrological phenomena, including saline and thermal stratifications, and pollutant loadings leading to eutrophication. Subsequent sediment bacteria analyses showed microbial diversity according to different depths in sediment, indicating the environmental change of sediment ecology. Moreover, the fish diversity in this study (2006-2007) was found to be considerably reduced compared to a similar study in 1989 (42% reduction), and the ecological health was deemed to be in a "poor" condition based on the 10-metric Lentic Ecosystem Health Assessment (LEHA) model. Accordingly, these results indicate that aquatic ecosystems are detrimentally affected by estuarine dams that block tidal flows, and when applied to short/long-term management strategies for artificial lakes in estuaries, suggest that similar construction projects have to be suitably controlled.
Lee
Young Geun
YG
Department of Environmental Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea.
An
Kwang-Guk
KG
Ha
Phuc Thi
PT
Lee
Keun-Young
KY
Kang
Joo-Hyon
JH
Cha
Sung Min
SM
Cho
Kyung Hwa
KH
Lee
Yun Seok
YS
Chang
In Seop
IS
Kim
Kyoung-Woong
KW
Kim
Joon Ha
JH
Kimj
Joon Ha
JH
D000818:Animals; D044822:Biodiversity; D017753:Ecosystem; D005399:Fishes; D005618:Fresh Water; D019015:Geologic Sediments; D056910:Republic of Korea; D012621:Seasons