• Korean Journal of Environment and Ecology
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• v.25 no.5
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• pp.691-709
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• 2011

This study was performed to classify habitat types depending on environmental factors and to find out distribution characteristics of functional feeding groups of aquatic insects which were collected at that habitat types. Field survey was conducted twice in a year for every spring and fall from 2007 to 2008 for 38 sites in the Geum River. During the field survey 15 environmental factors were measured at each 38 sites and analyzed by similarity analysis method to classify habitat types. The result of similarity analysis showed that the 38 sites could be grouped into 7 classes like as C1 and C3 class belong to Head water(HD), C2 and C4 and C5 class belong to Middle stream(MS), C6 and C7 class belong to Large River(LR) based on euclidean distances 4. And also, we could extract the main environmental factors affecting the classification of habitat types such as Stream Width and Elevation of physical environmental factors, Water Temperature, Conductivity and DO of chemical environmental factors, percentages of Sand, Silt and Gravel of substrate factors. Total 142 species of aquatic insects in 46 families, 9 orders were collected during the field surveys and the occurrence number of species and individuals showed high correlation with the Velocity factor and the percentage of Sand factor of each habitat types. In addition, correlation analysis between functional feeding groups and environmental factors represented that (1) Filtering-collectors(FC) affected by Velocity, Stream Width and Silt, (2) Gathering-collector(GC) affected by Velocity, (3) Predator(P) affected by Elevation, Velocity, Boulder, Conductivity and Sand, (4) Plant-piecer(PP) affected by Water Width and Silt, (5) Scraper(SC) affected by Elevation and Conductivity, (6) Shredder(SH) affected by Elevation, Boulder, DO, pH, Conductivity and Water Temperature respectively. As a result of this study, Elevation, Stream Width, Velocity, Conductivity, Water Temperature and percentage of Sand factors which were deduced by stepwise multiple regression analysis had correlations($r{\geqq}0.600$, p<0.01) with biota community inhabitation. Therefore these six environmental factors were regarded as major environmental factors that might affect highly the distribution of functional feeding groups in stream ecosystem of the Geum River.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.929-936
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• 2011

To treat non-point source pollution in Dongbok lake, removal efficiencies of pollutants were investigated in Dongbokcheon constructed wetlands (CWs) at different treatment time and wastewater loading. The wetlands consisted of forebay, wetlands ($1^{st}$, $2^{nd}$, $3^{rd}$, $4^{th}$, $5^{th}$, $6^{th}$, $7^{th}$, and $8^{th}$ wetlands) and sedimentation pond. The concentrations of BOD, SS, T-N, and T-P in inflow ranged $0.85{\sim}3.14mg\;L^{-1}$, $3.33{\sim}9.70mg\;L^{-1}$, $0.64{\sim}5.33mg\;L^{-1}$, and $0.03{\sim}0.10mg\;L^{-1}$ from April to October in 2008, respectively. The removal rates of BOD, SS, T-N, and T-P in Dongbokcheon CWs were 34%, 5%, 31%, and 13%, respectively. The removal rates of BOD and T-N were higher than those for SS and T-P. The amounts of pollutant removal in Dongbokcheon CWs were higher in the order of forebay > wetlands > sedimentation pond for BOD, sedimentation pond > wetlands > forebay for SS, sedimentation pond > forebay > wetlands for T-N. The amount of T-P removal in wetlands was higher than forebay and sedimentation pond.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.3
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• pp.400-407
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• 2011

To evaluate the aquatic ecological characteristics in Sinpyongcheon constructed wetlands for treating nonpoint source pollution, the removal rates of nutrients in water, the total amounts of T-N and T-P uptakes by water plants, and chemical characteristics of T-N and T-P in sediment were investigated. The concentrations of BOD, COD, SS, T-N and T-P in inflow were 0.07~1.47, 0.60~2.65, 0.50~4.60, 1.38~6.26 and $0.08{\sim}0.32mg\;L^{-1}$, respectively. The removal rates of BOD, COD, SS, T-N, and T-P were 14%, 6%, 18%, 24%, and 10%, respectively. The maximum amount of T-N uptake by water plants in August was $813mg\;plant^{-1}$ for Phragmites communis TRIV in $2^{nd}$ bed, $1,172mg\;plant^{-1}$ for Typha orientalis PRESL in $3^{rd}$ bed, respectively. The maximum amount of T-P uptake by water plants in August was $247mg\;plant^{-1}$ for Phragmites communis TRIV in $2^{nd}$ bed, $359mg\;plant^{-1}$ for Typha orientalis PRESL in $3^{rd}$ bed, respectively. Organic matter, T-N, and T-P contents in sediments were high in the order of $1^{st}$ bed > $2^{nd}$ bed > $3^{rd}$ bed. Microbial biomass C/N/P ratios in sediments in $1^{st}$, $2^{nd}$, and $3^{rd}$ were 78~110/3~6/1, 73~204/1~6/1, and 106~169/1~6/1, respectively.

• Journal of Environmental Impact Assessment
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• v.27 no.6
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• pp.685-694
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• 2018

We measured ecological niche space (ENS) using carbon and nitrogen stable isotope ratios of benthic macroinvertebrates to estimate its applicability for large river assessment. In particular, we compared ENSs of selected macroinvertebrates between upper and lower area of Seungchon Weir in Yeongsan River to estimate the impact of weir on biological community. We also measured basic water quality and community indices including benthic macroinvertebrates index (BMI) to estimate their correlations with calculated ENS. ENS was calculated using the Bayesian Stable Isotope in R statistics (package "SIBER"). The results showed that seasonal variations in water quality and community indices were found, but there was no apparent tendency between upper and lower area of the Seungchon Weir in June (before rainy season) and August (after rainy season). However, ENS of benthic macroinvertebrates markedly decreased across the weir in both June and August regardless of changes in water quality. This means the physical change of the stream due to the weir cause decrease of ecological isotopic niche space of benthic macroinvertebrates regardless of water quality, suggesting physical modification by the weir can affect the interaction between habitat condition and macroinvertebrates. Therefore, the ecological isotopic niche space can be a useful supplementary indicator for the river ecosystem assessment.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.2
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• pp.317-324
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• 2012

To reduce non-point source pollutants in Juam Lake eco-wetlands, purification efficiencies of pollutants were investigated at three different systems. The constructed wetlands (CWs) consisted of A system, B system and C system. A system consisted of $1^{st}$ free water surface (FWS) CW, $2^{nd}$ FWS CW, $3^{rd}$ FWS CW, $4^{th}$ subsurface flow (SSF) CW and $5^{th}$ SSF CW. B system consisted of $1^{st}$ FWS CW, $2^{nd}$ FWS CW, $3^{rd}$ FWS CW, $4^{th}$ FWS CW and $5^{th}$ SSF CW. C system consisted of $1^{st}$ FWS CW, $2^{nd}$ FWS CW, $3^{rd}$ FWS CW, $4^{th}$ FWS CW and $5^{th}$ SSF CW. The concentrations of BOD, COD, SS, T-N and T-P in inflow ranged 0.20 ~ 0.91, 1.24 ~ 8.00, 0.60 ~ 8.60, 0.04 ~ 2.50 and $0.001{\sim}0.685mg\;L^{-1}$ from March to October in 2011, respectively. Removal rates of BOD, SS, T-N and T-P were high in Autumn, Spring, Spring and Summer, respectively. In A system, $1^{st}$ FWS CW, $2^{nd}$ FWS CW and $3^{rd}$ FWS CW were dominated by Leersia oryzoides. In B system, $1^{st}$ FWS CW, $3^{rd}$ FWS CW and $4^{th}$ FWS CW were dominated by Leersia oryzoides. In C system, $2^{nd}$ FWS CW and $3^{rd}$ FWS CW were dominated by Nymphaea teragona.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.4
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• pp.642-648
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• 2012

To evaluate the water quality in Juksancheon constructed wetlands for treating non-point source pollution, the removal rates of nutrients in water and the total amounts of T-N and T-P uptakes by water plants were investigated. Chemical characteristics of T-N and T-P in sediment were investigated. The concentrations of BOD (Biochemical Oxygen Demand), COD (Chemical Oxygen Demand), SS (Suspended Solids), T-N and T-P in inflow were 0.07~1.47, 0.60~2.65, 0.50~4.60, 1.38~6.26 and $0.08{\sim}0.32mg\;L^{-1}$, respectively. The removal rates of BOD, COD, SS, T-N, and T-P were -10, 51, 66, -3 and 5%, respectively. The maximum amount of T-N uptake by water plants in August was $368.7mg\;plant^{-1}$ in the $2^{nd}$ treatment stage by Nymphoides peltata, $1314.6mg\;plant^{-1}$ in the $3^{rd}$ treatment stage by Iris pseudacorus, $1160.4mg\;plant^{-1}$ in the $4^{th}$ treatment stage by Nymphaea tetragona GEORGI, respectively. The maximum amount of T-P uptake by water plants in August was $121.7mg\;plant^{-1}$ by Nymphoides peltata in the $2^{nd}$ treatment stage, $268.7mg\;plant^{-1}$ by Iris pseudacorus in the $3^{rd}$ treatment stage and $212.0mg\;plant^{-1}$ by Nymphaea tetragona GEORGI in the $4^{th}$ treatment stage, respectively. Organic matter contents in sediments were not different. Contents of T-N and T-P in sediments were higher in spring. Microbial biomass C:N:P ratios in sediments in spring, summer, autumn and winter were 117~140:1~4:1, 86~126:5~6:1, 68~101:2~6:1 and 47~138:2~4:1, respectively. We could conclude that Juksancheon constructed wetlands show high removal efficiencies of COD and SS. However, improvements of management in winter season should be considered to improve the removal efficiencies of pollutants.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.12
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• pp.886-892
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• 2011

In a study on THMs formation at the distribution facilities in Seoul water supply for past 3 years from 2007 to 2009, THMs production was increased from inlet to outlet during the process in water treatment plant. However, such increased THMs amount was very small compared to THMs production formed after pre-chlorination and post chlorination. Accordingly, this study is aimed to investigate the characteristics of water quality parameters of Han River related to THMs formation in 6 water treatment plants in Seoul. The results showed that THMs and other factors such as temperature (r = 0.539~0.846) and turbidity (r = 0.421~0.863) had positive correlation while THMs had negative correlation with pH (r = -0.613~-0.800) and algae (r = -0.582~-0.901). There is no correlation between THMs and $NH_3-N$. According to the factor analysis, generally metabolite and organic matter factor $X_1$ (pH, BOD, algae), and seasonal and natural factor $X_2$ (temperature, turbidity) played an important role in the formation of THMs. Multiple regression analysis for THMs formation showed significance of regression appeared in most water systems.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.5
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• pp.836-841
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• 2012

Distributions and growth of submerged plants with water level were investigated in a flood control reservoir around Dongbok Lake. In adddition, the total amount of biomass and uptakes of plants per unit area ($m^2$) in the flood control reservoir were investigated. The total vegetation area was $156,871m^2$ in the Dongbok flood control reservoir ($209,160m^2$) before flooding. By July 11, the Dongbok flood control reservoir was flooded during rainy season except for upper area. Dominant plants were CRXDM (Carex dimorpholepis Steud), ECHCF (Echinochloa crusgalli), POLHY (Polygonum hydropiper L) and BROTE (Bromus tectorum L) which occupied 75% of the flood control reservoir. The total amounts of organic matter uptakes per unit area ($m^2$) with distribution rates by CRXDM, ECHCF, POLHY and BROTE under different submerged plants were 65.5, 6.8, 7.0 and 13.0%, respectively. The total amount of nitrogen uptakes per unit area ($m^2$) with distribution rates at different submerged plants were in the order of CRXDM ($1.30g\;m^{-2}$) > POLHY ($0.34g\;m^{-2}$) > BROTE ($0.30g\;m^{-2}$) > ECHCF ($0.25g\;m^{-2}$). The total amounts of phosphorus uptakes per unit area ($m^2$) with distribution rates at different submerged plants were great in the order of CRXDM (51.8%) > BROTE (17.7%) > POLHY (10.3%) > ECHCF (9.6%). Thus, the results of this study suggest that O.M, T-N and T-P by submerged plants in Dongbok Lake were strongly influenced at water quality in flood control reservoir.

• Journal of Korea Water Resources Association
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• v.50 no.4
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• pp.263-275
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• 2017

Integrated numerical approaches with physically-based conceptualization are required for accurate urban inundation simulation. In this study, we described, applied and analyzed an integrated 1-dimensional (1D) sewerage system and 2-dimensional (2D) surface flow model, which was suggested by Lee et al. (2015). This model was developed based on dual-drainage concept, and uses storm drains as an discharge exchange spot rather than manholes so that interaction phenomena between surface flow and sewer pipe flow are physically reproduced. In addition, the building block concept which prevents inflows from outside structures is applied in order to consider building effects. The capability of the model is demonstrated via reproducing the past flooding event at the Sadang-cheon River catchment, Seoul, South Korea. The results show the plausible causes of the inundation could be analysed in detail by integrated 1D-2D modeling.

• Journal of Environmental Science International
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• v.14 no.11
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• pp.1057-1062
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• 2005

The present study investigated runoff characteristics of non-point pollutants and discharge load amount according to the land utilization in Yeinam river basin. The land utilization of target basin was divided into paddy field, dry field, forest, residential area and composition area. The study on the runoff characteristics of non-point pollutants by rainfall-runoff process showed that COD, SS and T-P had the first-flushing effect with relatively high concentration in early-stage of the rainfall-runoff process, but the T-P revealed similar runoff characteristics. Event Mean Concentration(EMC) of BOD and COD according to the land utilization revealed the range of $3.11\~15.50mg/L$ and $3.37\~33.42mg/L$, and the highest concentration of EMC corresponding to BOD and COD was detected in the paddy field. The EMC of SS showed $1.7\~305.02mg/L$ and it's highest concentration was found in the dry field. The EMC of T-N and T-P represented the highest concentration in the paddy field and dry field with range of $0.91\~8.76mg/L$ and $0.02\~0.44mg/L$.