• Journal of Korean Society of Water and Wastewater
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• v.18 no.3
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• pp.357-365
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• 2004

Effect of artificial circulation on amelioration of water quality in Yeoncho Lake was analyzed using summer data between 1991-2002. Two sites, intake tower area where aeration systems are concentrated in and near the inlet of reservoir were selected for comparison in this study. Summer averages between may and september Showed that aeration system might be beneficial in the improvement of water quality of BOD5, COD, and TN while Chl-a concentration and transparency did show opposite pattems. Wilcoxon's singed rank test for matched pair indicated slight increase of BOD5 and COD concentrations in the vicinity of intake tower while other variables did not show any significant differences from data of inlet of reservoir. During the study, it was found that the following subjects need to be investigated for more detailed analysis. 1) Dynamic pollutant loading from outside and inside the lake, 2) Biological, Chemical and Physical lake data when aeration systems are in and not in operation and 3) Radius of influence of aeration system.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.4
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• pp.445-452
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• 2004

Intermittent deep draw artificial circulation system is one of the most widely used destratification systems to control algal bloom in reservoirs in Korea. However, there have been neither theoretical background of design criteria nor operation guide line for efficient application of the system available for such systems. A design method was developed to calculate required compressor capacity and number of circulation units considering physical interactions between stratified water layers and plumes induced by the intermittent deep draw artificial circulation system. The program was tested with data observed in Yeoncho Lake. The results indicated that the developed method can applied in the fields successfully. Further validation processes would improve design and operation methods.

• Korean Journal of Environment and Ecology
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• v.29 no.1
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• pp.29-45
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• 2015

Water chemistry and fish community, based on fish compositions and ecological characteristics(trophic/tolerance guilds and condition factor), were compared in Gucheon Reservoir($G_cR$) and Yeoncho Reservoir($Y_cR$). Chemical parameters of water quality such as BOD, COD, nutrient(N, P) and suspended solids indicated that water quality was better in the $Y_cR$ than $G_cR$, and the temporal variability in seasonal and interannual patterns were greater in the $Y_cR$. The greater variability was mainly attributed to intense dilutions of reservoir water by Asian monsoon rain during July-August. Fish guild analysis indicated that species diversity was higher in the $G_cR$ than the $Y_cR$, and that the proportion of tolerant and omnivore species were greater in the $Y_cR$. Regression analysis of body weight-total length showed that the regression coefficient(b value) was lower in the $G_cR$(2.15 ~ 2.40) than the $Y_cR$(2.59 ~ 3.14). Condition factor(K) of fish against the total length showed negative slope of Zacco temminckii, Carassius auratus, Pseudorasbora parva and Rhinogobius brunneus population in the $G_cR$, and a positive slope of Carassius auratus and Rhinogobius brunneus population in $Y_cR$. Overall, our data suggest that the growth of the fish populations, based on the length-weight relations and condition factor, reflected the trophic regime of nutrients and organic matter.

• Journal of the Korean Society for Marine Environment & Energy
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• v.5 no.3
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• pp.16-22
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• 2002

The effect and the overall optimal operation of artificial aeration devices for mixing of thermally stratified water reservoir are under study, and its brief introduction is made. The study site is Yeoncho Lake in Geojae island, which is well known for its eutrophication problems in the summer. A few samplings have been made before and after the operation of two types of artificial aerators, and the effect is believed to be positive. Also, design methodology for such artificial aerators is reviewed and a few are applied to the case of Yeoncho Lake. Schladow's[1993] proposal is believed most proper based on the information we have gathered by now. In addition, a simple numerical experiment is also peformed to see the overall effect of the device on the flow and temperature profile.