• Korean Journal of Ecology and Environment
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• v.43 no.2
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• pp.190-198
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• 2010

This study was conducted to examine the effects of dams on benthic macroinvertebrate communities in Korean streams and rivers. Four low-head dams and three large dams were studied throughout South Korea. Sampling was taken at immediately upper (impoundment), lower (riffle area), and control (riffle area) sites from the dams during 2004-2007. The upper sites, of which substrate heterogeneity and velocity were relatively low, showed a lower degree of species richness, density, and diversity indices, which is very different from the lower and control sites. Heavily polluted streams showed a lesser degree of community differences between the upper and lower sites. In the large dams, the upper and lower sites showed very low values of species diversity indices and very high values of dominance indices compared to the control sites. In the low-head dams, however, the difference of degree of the values was relatively smaller. Compositions of the functional feeding groups and the habitat orientation groups were relatively simpler at the upper sites than at the lower sites and the degree of difference was greater in the large dams. Species richness and community indices of benthic macroinvertebrates were more significantly affected by habitat characteristics than water quality at the upper sites; however, those were more significantly related with water quality at the lower sites. In conclusion, large and low-head dams could simplify stream habitats particularly at the upper sites (impoundment), and they negatively affected on the benthic macroinvertebrate communities inhabited the habitats. The impact was larger in the large dams than in the low-head dams.

• Journal of Korea Water Resources Association
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• v.47 no.6
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• pp.501-511
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• 2014

The effects of initial conditions and input values of the rainfall-runoff model were studied in the applications of a lumped concept model for flood event data extension. For the initial conditions of the rainfall-runoff model, baseflow effects and spatial distributions of saturation points ($R_{sa}$) for the storage function methods (SFM) were analyzed. In addition, researches on the effects of rainfall data conditions as input values for the rainfall-runoff model were performed. The Chungju Dam watershed was selected and divided into 3 catchments including smaller size of 22 sub-catchments. The observed discharge and inflow amounts at Yeongwol 1, Chungju Dam, and Yeongwol 2 water level stations were individually operated as criteria for flood data extension in 30 flood events from 1993 to 2009. Direct and base flow were distinguished from a stream flow. In order to test capability of flood data extension, obtained base flow was applied to the rainfall-runoff model for three water level stations. When base flow was adopted in the model, the Nash-Sutcliffe Efficiency(NSE) was increased. The numbers of over satisfaction for model performance (>0.5) were increased over 10%. Saturation points ($R_{sa}$) which strongly influence the runoff amount when rainfall starts were optimized based on the runoff amount at three water level stations. The sizes of saturation points for three locations were similar which means saturation point size is not depending on the runoff amount. The effects of rainfall information for flood runoff were tested at 2002ev1 and 2008ev1. When increased the amount of rainfall information, the runoff simulations were closer to the simulations with full of rainfall information. However, the size of improvement was not substantial on rainfall-runoff simulations in terms of the size of total amount of rainfall.

• Journal of the Korea Organic Resources Recycling Association
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• v.26 no.1
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• pp.65-78
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• 2018

According to the in social aspects such as population growth, urbanization and industrialization, development of livestock industry by meat consumption, amount of organic wastes (containing sewage sludge and food waste, animal manure, etc) has been increased annually in South Korea. Precise monitoring of 11 organic wastes biogas facilities were conducted. The organic decomposition rate of organic wastewater was 68.2 % for food wastes, 66.8 % for animal manure and 46.2 % for sewage sludge and 58.8 % for total organic wastes. As a result of analyzing the biogas characteristics before and after the pretreatment, the total average of the whole facility was measured to be 560 ppm using iron salts and desulfurization, and decreased to 40 ppm when the reduction efficiency was above 90 %. Particularly, when iron salt is injected into the digester, the treatment efficiency is about 93 %, and the average is reduced to 150 ppm. In the case of dehumidification, the absolute humidity and the relative humidity were analyzed. The dew point temperature of the facility where the dehumidification facility was well maintained as $14^{\circ}C$, the absolute humidity was $12.6g/m^3$, and the relative humidity was 35 %. Therefore, it is necessary to compensate for the disadvantages of biogasification facilities of organic waste resources and optimize utilization of biogas and improve operation of facilities. This study was conducted to optimize biogas utilization of type of organic waste(containing sewage sludge and food waste, animal manure) through precision monitoring.

• Korean Journal of Environment and Ecology
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• v.26 no.1
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• pp.46-56
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• 2012

Benthic macroinvertebrates were investigated in Hoeongseong Lake region from March to October 2010, Korea. Macroinvertebrate communities, composition of the functional feeding groups, habitiat oriented groups and the biological water quality were assessed above and below Hoeongseong Dam in the lake region. Six sites, two (St.1~2) above the lake, two (St. 3~4) into the lake, and two (St. 5~6) below the dam, were selected for quantitative (Surber sampler $30cm{\times}30cm$, mesh size 0.2 mm) and qualitative (Hand net) samplings of benthic macroinvertebrates. As a result, a total of 83 species belonging to 43 families, 17 orders, 8 classes, and 5 phyla were recognized. The EPT-group (50 spp. : 60.24%) that is major taxa or EPT-group plus Diptera (61 spp. : 73.49%) occupied most of benthic macroinvertebrates community. Based on quantitative sampling, the number of benthic maroinvertebrates above the lake was 2,399 individuals including 54 species, 28 families, 11 orders, 4 classes, and 4 phyla, whereas 510 individuals including 16 species, 12 families, 7 orders, 4 classes, and 3 phyla in the lake and 626 individuals including 62 species, 33 families, 13 orders, 6 classes, and 4 phyla below the dam were collected respectively. Dominance index was the highest, with 0.82-0.93 ($0.87{\pm}0.05$) in Hoeongseong lake (St. 3-4), diversity index was 3.04-3.16 ($3.10{\pm}0.06$), evenness index was 0.79-0.85 ($0.82{\pm}0.03$), and richness index was 7.27-8.52 ($7.90{\pm}0.63$), which were relatively higher below the dam sites. In the functional feeding groups, collector-gatherers and collector-filterers were the highest in the whole sites, and predators (Micronecta sedula) was appeared highly in the lake. Moreover, swimmers, burrowers, and clingers were considerably occupied in all collecting sites. The result of the DCA, similarity analysis, and MRPP were well reflective of the composition of lake and stream macroinvertebrates. ESB indicate that the lake sites were evaluated heavily polluted under priority improvement waters. Also, Semisulcospira gottschei, Ecdyonurus kibunensis, Epeorus pellucidus, Rhoenanthus coreanus, Stenelmis sp., and Cheumatopsyche brevilineata are considered as an indicator species above and below Hoeongseong Lake, whereas Macrobrachium nipponense and Micronecta sedula are indicated in the lake.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.30 no.4
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• pp.14-22
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• 2012

The position, size and landscape of the former Donam SeoWon as well as the physical organization of the old site, are studied to extract data for the enhancement of the authenticity of Donam SeoWon since its registration as a world heritage site. The results are as follows. The 'Donam(豚巖)' encaved rock, the tombstone of teacher Sagye(沙溪), Kimjipsadang(金集祠堂), the head of the Gwangsan Kim family, the Sagye stream in front of them, and the Gyeryong and Daedun mountains in the distance are united in the former Donam SeoWon as landscape elements that clearly show the characteristics of the former site, which was called 'Donam-Wollim(豚巖園林).' Moreover Yangseongdangsipyoung(養性堂十詠), adds the garden elements of a medical herb field, twins pond, a bamboo forest, a school, and a peach field. On this site, one can also engage in activities that are related to the land and are closely related to Neo-Confucianism such as fish watching, conferencing, visit in seclusion(訪隱), looking for monks, and overseeing farming. The former site facing east is assumed to have Sau(祠宇) - Eungdodang(凝道堂) - Ipdeokmum(入德門) - Sanangru(山仰樓: estimated). Jeonsacheong seems to have been located to the left of the Sau area, Yangseongdang, which contained upper and lower twin lotus ponds, on the right and was surrounded by various plants. As it has been used as a lecture hall for the past 250 years, the former Donam SeoWon, located 1.8km away from the current area, must be preserved, and the landscape should be formed to establish the authenticity of Donam SeoWon.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.28 no.3
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• pp.98-104
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• 2010

The objective of this study was to understand the origin and characteristics of stone tower's style through the study of the 'Village Shrine at Seoji-ri, Andong'. The three kinds of stone towers were located forming a line of 9m on the hill of a red pine forest along the stream in the village. Toward the direction looking at the village, the three-story stone located on left, the two-story stone located in the middle, and the common style stone tower located on right. The bottom part of the three-story stone was 2.5m in length, 1.8m in width, 1.3m in height. The bottom part of the two-story stone was 1.3m in length, 1.5m in width, 0.9m in height. The common style stone heap tower was 3.0m in diameter, 1.8m in height with a cone shape. The small hat-shaped stone was presumed to be the top part of a three-story stone. According to the three factors(heaven, earth, human) of the idea of the universe in Korea, most ancient remains have components of odd numbers. Then it had been substituted with smaller three-story stone(at present, two-story stone). And then altered to a common stone tower later, such as the 'Village Shrine at Seoji-ri, Andong' that shows the combination of the Bronze Age's megalithic and a folk religion. The 'Village Shrine at Seoji-ri, Andong' is a valuable relic that shows the stone towers, and is derived from the Bronze Age. The 'Village Shrine at Seoji-ri, Andong' shows that the 'Village Shrine at Seoji-ri, Andong' was embodied the three-factor(heaven, earth, human) idea of the universe in three-story stone of megalithic culture' remains.

• Economic and Environmental Geology
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• v.47 no.6
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• pp.589-599
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• 2014

This study selected optimal sites in Myeongsasimni located in west coast of Korea for stratigraphic research containing extreme climate event during quaternary period by spatio-temporal analyses of changes in sedimentary environment and land use employing 1918 topographic map, 2000 digital terrain map, 1976 and 2012 air photographies. The study area shows no significant changes in topographic characteristics that hilly areas with relatively large variations in elevation are distributed over north and south part of the study area, and sand dues are developed along the coast line. Moreover, flat low lying areas are located at the back side of the sand dues. The movement of surface run off and sediment loads shows two major trends of inland direction flow from back sides of sand dunes and outland direction flow from high terrains inland, and the two flows merge into the stream located in the center of the study area. Two sink with individual area of $0.2km^2$ are observed in Yongjeong-ri and Jaryong-ri which are located in south central part and south part of the study area, respectively. In addition, sea level change simulation reveals that $3.4km^2$ and $3.64km^2$ are inundated with 3 m of sea level rise in 1918 and 2000, respectively, and it would contribute to chase sea level change records preserved in stratigraphy. The inundated areas overlaps well with sink areas where it indicates the low lying areas located in south cental and south part of the study area are identical for sediment accumulation. The areas with minimal human impact on sediment records over last 100 years are $3.51km^2$ distributed over central and south part of the study area with the land use changes of mud and rice field in 1918 to rice field in 2012. The candidate sites of $0.15km^2$ in central part and $0.09km^2$ in south part are identified for preferable locations of geologic record of extreme climate events during quaternary period based on the overlay analysis of optimal sedimentary environment and land use changes.

• Korean Journal of Environmental Agriculture
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• v.27 no.1
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• pp.1-9
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• 2008

The main purpose of this study is to accumulate the fundamental data representing groundwater of plastic film houses by means of water quality and its multivariate statistical analysis. Groundwater samples were collected in every two years since 2000 to 2004 from total 211 sites. According to the result of water quality analysis, ground water quality was suitable for irrigation purpose averagely. Correlation analysis showed that EC was highest positively correlated with $Mg^{2+}$ to 0.810(p<0.01), 0.776(p<0.01) in April and July, respectively. $NO_3-N$ was highest positively correlated with T-N to 0.794(p<0.01) in October. This result shows that it can lead to a different result even in similar case sometimes. Four factors were extracted through factor analysis in April and July, but five factors were extracted in October. The proportions of cumulative variance by the factor were 64.9, 60.2, and 70.7 in April, July, and October, respectively. The first factor was highly related to anions and cations such as $Ca^{2+},\;Mg^{2+},\;Cl^-,\;{SO_4}^{2-}$, and EC in contrast to that of stream water. According to the cluster analysis, 211 sites are classified into four groups. Common type of ground water quality was shown in group A. The pH and $PO_4-P$ were highest in Group B. The anions and cations were highest in Group C. $COD_{Cr}$ was highest in Group D.

• Korean Journal of Ecology and Environment
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• v.48 no.3
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• pp.153-167
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• 2015

In order to understand the relationship between the distribution of epilithic diatoms and the habitual environments, land-use, water qualities, and epilithic diatoms were studied at 141 sampling sites in the midwestern stream of Korean peninsula (Geum river, Mangyeong river, Dongjin river, and Sapgyo river). The total 183 diatom taxa was appeared in the study, while the dominant species were found to be Nitzschia palea (10.9%) and Achnanthes convergens (8.4%). Based on the abundance of epilithic diatoms, a cluster analysis results indicate that the sampling sites divided the sampling sites into 4 groups (G) at the 25% level. In term of geographic and aquatic environments, G-I and -II accounted for the upper and mid streams of the Geum river, and had large forest areas and good in water quality. G-III accounted for farmland and urban, and high concentration nutrient levels (TN and TP) and electric conductivity. G-IV accounted for mostly farmland, and high levels in turbidity, BOD, nutrient and electric conductivity. CCA results showed that the saproxenous taxa Meridion circulare was the indicator species of G-I, which strongly influenced by altitude and forests. In G-II, the indifferent taxa Navicula cryptocephala was influenced by Chl-a, AFDM, and DO. In G-III and -IV, the indifferent taxa Fragilaria elliptica and saprophilous taxa Aulacoseira ambigua were influenced by electric conductivity, turbidity, and nutrient counts. Meanwhile, random forest results showed that the predicting factor of indicator species appearance in G-I, -II, and -III was found to be electric conductivity whereas in G-IV it was found to be turbidity. Collectively, the distribution of diatoms in the midwestern of Korean peninsula was found to depend more on the land-use and its subsequent water qualities than the inherent characteristics of the aquatic environment.

• Korean Journal of Ecology and Environment
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• v.40 no.3
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• pp.403-411
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• 2007

The purpose of the study was to evaluate fish community, based on conventional at Shannon-Weaver diversity index (H'), and ecological health, based on the Index of Biological Integrity (IBI) using fish assemblage in the eight sites of Nakdong River during June${\sim}$August 1999. Total number of species sampled was 19 species, and two sensitive species of Zacco temminckii (51%) and Rhynchocypris oxycephalus (28%) dominated the fish community. Also, trophic guild analyses showed that insectivore was 87% of the total and omnivore was rare, indicating that the ecological health is well maintained in the system. The pattern of spatial variation in the diversity index(H') was very similar to patterns of the species number and individual number, whereas the pattern of H' was not matched with the tolerance and trophic guild data. The diversity index (H') showed highest (1.56) in Site 6 where the proportion of sensitive species and tolerant species was minimum and maximum, respectively, and where the insectivore and omnivore were minimum and maximum. In other words, the diversity index was not matched at all with the trophic and tolerant guilds, indicating that the conventional index did not reflect the ecological characteristics of fish community in the system. In the mean time, the ecological health (IBI) averaged 33.5 (n=8), indicating "good${\sim}$fair condition" and the IBI values matched with trophic and tolerance guilds. Maximum IBI occurred in Site 2 where the sensitive and msectivore species were nearly maximum, and the tolerant and omnivore species were almost minima, indicating that IBI values were closely associated with the ecological functions and health conditions. Overall data suggest that the conventional diversity index may not effective for a evaluation of fish community, and that in contrast the IBI approach may be a useful tool for diagnosis of stream community.