• Journal of Korean Society of Environmental Engineers
• /
• v.34 no.12
• /
• pp.792-800
• /
• 2012

The study was performed to simulate the reduction efficiency of suspended solids (SS) for cultivated land located at riverine area at the Namhan River and the Bukhan River watershed sites (site A, B, C) under the rainfall conditions using HUFF & SCS UH-based VFS Design module of Web GIS-based VFSMOD System. The study indicates that the field 5% sloped, located at Bukhan River watershed (site A), requires at least 0.5 m width of Vegetative Filter Strip (VFS) to reduce 70% of SS while the field 10% sloped requires the at least 1.0~1.5 m width of VFS to reduce 70% SS, under the condition 106.2 mm of rainfall event and bell pepper or corn of crops. Against the conditions 95.1 mm of rainfall event and sweet potato or soy bean of crops, the field 5% sloped, located at Namhan River watershed (site B) requires at least 0.5 m width of VFS to reduce 70% of SS while the field 10% sloped requires at least 1.0 m width of VFS to reduce 50% SS. The crops sweet potato and soy bean are cultivated in the site C, located at Namhan River watershed, 1 m of VFS is capable of 64.0% and 62.0% of SS reduction against 102.6 mm and 151.2 mm rainfall conditions respectively, for the 5% sloped field. The result supports that VFS is one of most potential methods to reduce SS from cultivated area, which is environment-friendly hydrologic structure. The VFS design, however, needs to be simulated before its installation in the field, the simulation needs to consider not only various characteristics of the field but also different conditions affecting the VFS, using a model capable to consider a lot of factors.

• Korean Journal of Ecology and Environment
• /
• v.51 no.1
• /
• pp.60-70
• /
• 2018

The distribution of benthic macroinvertebrates was investigated at 1,157 sites of 7 main water systems in Korea, including 442 sites of Han River system (Namhan River, Bukhan River, Han River main stream, Anseongcheon, etc.), 305 sites of Nakdong River system (Nakdong River, Hyeongsan River, Taehwa River, etc.), 199 sites of Geum River system (Geum River, Sapgyocheon, Mangyeong River, Dongjin River, etc.) 102 sites of Seomjin River system (Seomjin River), 102 sites of Yeongsan River system (Yeongsan River, Tamjin River, etc.), and 7 sites of Jeju stream system. A total of 151 families were found in the whole survey sites, including 141 families in Han River, 122 in Nakdong River, 115 in Geum River, 106 in Seomjin River, 113 in Yeongsan River, and 50 in Jeju. Chironomidae (20.8%) was the most dominant species in Korea, followed by Hydropsychidae (17.1%), Baetidae (12.6%), Tubificidae (10.3%), Heptageniidae (8.6%), Ephemerellidae (6.3%), Asellidae (2.7%), Leptophlebiidae (2.4%), Planariidae (1.7%), and Tipulidae (1.6%). Substrates compositions consisted of large sand (22.6%), large gravel (18.4%), silt (10.5%), and boulder (8.2%). The mean stream width was 133.5 m and the mean watercourse width was 61.7 m. The mean water depth and velocity were 30.2 cm and $33.1cm\;s^{-1}$, respectively. Results of cluster analysis based on distributional characteristics of benthic macroinvertebrates were divided into six groups according to the frequency of benthic macroinvertebrate taxa which appeared in the study area. Finally, altitude, current velocity and substrate composition were the most influencial factors determining the distribution patterns of macroinvertebrate communities.

• Journal of the Korean Geographical Society
• /
• v.39 no.6 s.105
• /
• pp.833-844
• /
• 2004

In Chugaryeong rift valley, lava plateau formation by the fissure eruption had vanished original landforms and effected on drainage derangement and revision. 4 rivers including Namdae-cheon, Bukhan-gang, Imjin-gang and Hantan-gang watersheds have shared Cheolwon-Pyeonggang lava plateau, that is, ownerless watershed. Main agency of the dividing process are central-eruption volcanic peaks such as Orisan(453m) and 680 Peak. Especially, Orisan has played the role of divide point for 4 watersheds. In the lower-relief plateau zone, complex drainage system have caused continually river capture between neighboring watersheds. In more elevated range slope, river capture have proceeded to headward erosion. Hydrogeomorphologically, lava-filled valley has initiated decrease of the original size of flood plain, maybe, causing higher capability of inundation by heavy rains, and then more active dissection of lava plateau layer.

• Korean Journal of Environment and Ecology
• /
• v.22 no.2
• /
• pp.184-191
• /
• 2008

To investigate the effect of turbid water on fish population, the length-weight relationship and its condition factor were applied to Kumgang fat minnow Rhynchocypris kumgangensis collected in turbid (the Daegi and the Jaun streams) and non-turbid stream (the Bongsan and the Gyebang streams) for a year from 2004 to 2005. The mean length of minnow between turbid water and non-turbid water streams was not significantly different. In the South River system, the regression coefficients (b) based on length-weight relationship were 3.21 in the non-turbid Bongsan stream and 3.07 in the turbid Daegi stream, respectively. On contrary, the regression slope in the turbid stream was a little higher than that of the non-turbid stream located in the Bukhan River system. The values were 3.20 in the Gyebang-stream and 3.23 in the Jaun stream, respectively. Our result suggested that chronic turbid water effect on the level of fish population has a little or no effect.

• Korean Journal of Ecology and Environment
• /
• v.51 no.4
• /
• pp.287-298
• /
• 2018

The zooplankton community and environmental factor were investigated on a weekly basis from March to November 2015 in Lake Paldang, Korea. The seasonal succession of zooplankton community structure was influenced by hydraulic and hydrological factors such as inflow, outflow and rainfall. However, the hydraulic retention time in 2015 (16.3 day) was affected by the periods of water shortage that had continued since 2014 and increased substantially compared to 2013 (7.3 day). Therefore, the inflow and outflow discharge were decreased, and the water quality (COD, BOD, TOC, TP, Chl-a) of Lake Paldang (St.1) was the same characteristics as the river type Bukhan river (St.3), compared with the lake type Namhan river (St.2) and Gyeongan stream (St.4). Zooplankton community dominated by rotifers (Keratella cochlearis, Synchaeta oblonga) in spring (March to May). However, Copepod (Nauplius) and Cladoceran (Bosmina longirostris) dominated in St.4. In summer (June to August), there was a few strong rainfall event and the highest number of individuals dominated by Keratella cochlearis (Rotifera) and Difflugia corona (Protozoa) were shown during the study period. In autumn (October to November), the water temperature was decreased with decrease in the total number of individuals showing Nauplius (Copepoda) as the dominant species. As a result of the statistical analysis about zooplankton variation in environmental factors, the continuous periods of water shortage increased the hydraulic retention time and showed different characteristic for each site. St.1, St.3 and St.2, St.4 are shown in the same group (p<0.05), showing the each characteristics of river type and lake type. Therefore, the water quality of catchment area and distribution of zooplankton community would be attributed to hydraulic and hydrological factors.

• Journal of Korean Society of Environmental Engineers
• /
• v.32 no.4
• /
• pp.349-356
• /
• 2010

Ion chromatography (IC) coupled with conductivity detector (CD) is a common system for the determination of perchlorate in water samples. Although the IC method with CD has been widely used for the determination of trace level perchlorate ion in water, sensitivity decreases dramatically as the complexity of the matrices increases. Here we proposed the application of ion chromatography coupled with mass spectrometry (IC-MS/MS) to significantly improve selectivity of perchlorate. The mean recovery of the method was 104.4 ${\pm}$ 5.7% and the relative standard deviation (RSD%) was 1.9 ${\pm}$ 1.3%. The alculated method detection limit (MDL) was 0.0207 ${\pm}$ 0.0099 ${\mu}g/L$. The concentrations of perchlorate were minimum <0.1 ${\mu}g/L$ and maximum 18.3 ${\mu}g/L$ in source water (Namhan, Bukhan and Han River). Hongreung showed higher concentrations ($1^{st}$-14.3 ${\mu}g/L$, $2^{st}$-18.3 ${\mu}g/L$) than the other places. And the concentrations of perchlorate were 0.18~0.34 ${\mu}g/L$ in the samples taken from the six water treatment plants and six intake stations in Seoul.

• Korean Journal of Ecology and Environment
• /
• v.52 no.2
• /
• pp.71-80
• /
• 2019

Effects of environmental factors on phytoplankton succession and community structure were studied in Lake Chuncheon located in Bukhan River, South Korea. The data were sampled at three sites such as CC1 (lower side), CC2 (middle side), and CC3 (upper side of Lake Chuncheon) from 2014 to 2017. The annual average precipitation in Lake Chuncheon was 992 mm during the study period (2014~2017), and the annual precipitation was lower than 800 mm in 2014 and 2015. The annual average water temperature, total phosphorus (TP), and total nitrogen (TN) ranged from 17.0 to $21.1^{\circ}C$, 0.012 to $0.019mg\;L^{-1}$, and 1.272 to $1.922mg\;L^{-1}$, respectively. The TN concentration was relatively high in 2015 compared with the other study years, as a drought continued from 2014 to 2015. When comparing the correlation between precipitation and environmental factors, water temperature (p<0.01) and TP(p<0.05) showed positive correlations with rainfall. The average numbers of phytoplankton cells by branch were 2,094, 2,182, and $3,108cells\;mL^{-1}$ in CC1, CC2, and CC3, respectively. CC3 is considered advantageous for phytoplankton growth, even in small pollution sources due to low water depth. As a result of analyzing the relationship between precipitation and phytoplankton, the correlation between the two was shown to be high for 2016 (p<0.01) and 2017 (p<0.05), which is when precipitation was high. However, the correlation was not clear to 2014 and 2015. The relationship between water temperature and phytoplankton indicated a negative correlation with diatoms (p<0.01), yet positive correlations with green algae (p<0.01) and cyanobacteria (p<0.01). Diatoms increased in spring and autumn, which are characterized by low water temperature, and green algae and cyanobacteria increased in summer, when the water temperature is high. Our findings provide a scientific basis for characteristics of phytoplankton and water quality and management at the Lake Chuncheon.

• Journal of Wetlands Research
• /
• v.13 no.3
• /
• pp.515-522
• /
• 2011

This study examined the epiphytes using stable isotopes. Separated epiphytes should represent the water quality. In study areas, where agricultural paddies were prevailing, biomass of epiphytes can increase nitrogen isotopes(${\delta}^{15}N$) and as a result decrease in carbon isotopes(${\delta}^{13}C$). Naerin stream and Inbuk upper areas showed higher nitrogen isotopes(${\delta}^{15}N$) than in Hangye and Buk stream. Also, stable carbon isotopes(${\delta}^{13}C$) in Naerin stream and Inbuk streams tended to increase than in Hangye and Buk stream. This can indicate the epiphytes can be a good indicator for water quality pollution.

• Korean Journal of Ecology and Environment
• /
• v.38 no.3 s.113
• /
• pp.297-303
• /
• 2005

The analysis of fish community structure in the Peace Dam, Korea, was investigated from April 2003 to September 2004. Eight families and 31 species were collected during the period surveyed. Korean endemic species were 13 and the relative abundance was 41.9% of the total, along with Hemibarbus mylodon, Acheilognathus yamatsutae and Coreoleuciscus splendidus. Dominant was Hemibarbus labeo (14.1%) and subdominant species was Zacco temmincki (13.7%). Also, Z. platypus (11.9%), H. longirostris (9.3%), and Siniperca scherzeri (8.1%), were numerous. The biomass of collected fishes were H. labeo (24,278 g), S. scherzeri (19,487 g), Anguilla japonica (10,400 g), Cyprinus carpio (8,418 g), and Carassius auratus (4,020 g), According to the community analyses, the artificial reservoir with in the Bukhan River system were divided into 2 groups by unweighted pair-group method analysis (UPGMA), and it revealed that the community structure in Peace Dam was similar to those in Soyang and Paro Reservoirs.

• Korean Journal of Ichthyology
• /
• v.18 no.2
• /
• pp.78-86
• /
• 2006

We examined the genetic diversity in intra-populations of Korean shiner, Coreoleuciscus splendidus, in six major rivers (Bukhan, Namhan, Geum, Osipcheon, Nakdong and Seomjin river) of Korea based on two different mitochondrial genes, the mitochondrial cytochrome b and the 16S rRNA. Analysis of sequence variation in a 657-bp segment of the mitochondrial cytochrome b gene revealed deep divergence among populations (98.2~99.9%) and high genetic diversity from geographically isolated populations. Intra-specific variation in this 697-bp segment of the 16S rRNA gene sequences was very low and nearly identical. Six isolate populations of C. splendidus showed a high similarity (97.7%~99.7%). This result may be indicative of a complex history of connection and isolation of the rivers in the Korea peninsula.