• Korean Journal of Ecology and Environment
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• v.39 no.2 s.116
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• pp.198-208
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• 2006

This research was to apply a multi-metric approach, so called the Index of Biological Integrity (IBI) as a tool for biological evaluations of water environments, to a wadable stream. For the study, we surveyed 5 sampling locations in Kap Stream during August 2004 ${\sim}$ September 2005. We also compared the biological data with long-term water quality data, obtained from the Ministry of Environment, Korea and physical habitat conditions based on the Quantitative Habitat Evaluation Index (QHEI). We used ten metric systems for the IBI model to evaluate biological stream health. Overall IBI values in Kap Stream averaged 24 (range: 20${\sim}$30, n=5), indicating a "fair ${\sim}$ poor" conditions according to the modified criteria of Karr (1981) and US EPA(1993). Exclusive of 4th survey, average IBI values at the upstream reach (S1 ${\sim}$ S3)and downstream reach (S4 ${\sim}$ S5) were 20 and 24, respectively. However, in 4th survey the averages were 21 and 20 in the upstream and downstream reaches, respectively. This difference was larger in the upstream than in the downstream because of physical condition disturbed during summer monsoon. Values of the QHEI varied from 75(fair condition) to 148 (good condition) and values of QHEI in the S3 were significantly (P=0.001, n=5) lower than other sites. Biochemical oxygen demand (BOD), chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) were greater by 3 ${\sim}$ 8 fold in the downstream than in the upstream reach. We believe that present IBI approach applied in this study may be used as a key tool to set up specific goals for restoration of Kap Stream.

• Journal of Korean Society of Forest Science
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• v.86 no.4
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• pp.509-520
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• 1997

This is a report on the early vegetation, plant community structure, and secondary succession of cut and uncut sites of burned areas in Mt. Gumo-sun. The forest fire occurred on April, 1994 and the pine forest and its floor vegetation were burned down. The investigation was carried out from April, 1995 to October, 1996. The results are summarized as follows : The floristic composition of cut and uncut sites of burned area and unburned area were composed of 32, 36, and 34 kinds of vascular plants respectively. The biological spectra showed the $H(G)-D_1-R_5-e$ type, $H(M)-D_1-R_5-e$ and $M(N)-D_1-R_5-e$ in cut, uncut, and unburned site respectively. The dominant species based on $SDR_3$ of the cut site were Miscanthus sinensis var. purpurascens(100.00). Caret humilis(52.27), Quercus serrata(51.19) and Lysimachia clethroides(39.40), however, in the uncut sites the dominant species were Quercus acutissima(56.91), Pinus densiflora(26.83) in the tree layer, Quercus serrata(50.43), Lindera glauca(40.51), Lespedeza bicolor(37.85) in the shrub layer, and Miscanthus sinensis var. purpurascens(72.27), Pteridium aquilium var. latiusculum(60.92), Carex humilis(63.63) in the herb layer. Pinus densiflora(99.88), Miscanthus sinensis var. purpurascens(82.74), Quercus serrata(77.47) and Carex humilis(74.02) were dominant in the unburned site. The species diversity(H) and evenness index(e) were 1.05, 0.70 and 1.32, 0.85 in the cut and uncut site, respectively and 0.22, 0.63 in the unburned site. Dominance index(C) was 0.15, 0.06 and 0.96 in the cut, uncut site and unburned site, respectively. Degree of succession(DS) was 345.19, 747.47 and 674.34 in cut, uncut and unburned site, respectively. The index of similarity(CCs) was 0.66 between cut and uncut sites, 0.50 between unburned and cut sites and 0.61 between unburned and uncut sites. The amount of exchangeable sodium, calcium, magnesium and soil pH were increased, but the amount of organic matter, available phosphous, total nitrogen, total carbon and exchangeable potassium were decreased in cut site after fire.

• Korean Journal of Environment and Ecology
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• v.23 no.4
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• pp.353-364
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• 2009

This study was conducted to evaluate the effect of erosion control works on the stream ecosystem in a mountain torrential stream. The species composition of benthic macroinvertebrates and biological water quality were investigated before and after construction of erosion control works at 5 sites. The total number of benthic macroinvertebrates before construction was 3,086 individuals including 4 phyla, 6 classes, 11 orders, 22 families, and 25 species, but after construction it has decreased to 1,208 individuals including 4 phyla, 6 classes, 10 orders, 17 families, and 19 species. Especially, the diversity, richness, and evenness indices, which were calculated based on existing number of biological species, have decreased or not produced at the erosion control sites, where biological species were not found or the minimum number of species were found. The results of community analysis of benthic macroinvertebrates and ESB(Ecological Score of Benthic macroinvertebrate community) indicated that the environmental qualities of the stream based on saprobity, environmental condition, and water quality decreased after the construction at all sites: before construction, the top of the stream was satisfactory and some satisfactory, the middle was some defectiveness, and the lower was defectiveness and very defectiveness; after construction, all parts of the stream except some parts of the top were very defectiveness. Moreover, the water quality of torrential stream was rated between I to III before construction, but after construction, it declined to $IV{\sim}V$ except control. The habitat damage of benthic macro invertebrates occurred at all investigation sites after the construction of erosion control works led to reduction of the number of biological species and water quality deterioration. The results reported in this study were collected directly after the construction of erosion control works. Therefore, additional studies are needed to further explore the effect of disaster-prevention of erosion control works and the recovery process of stream ecosystem through long term monitoring.

• Korean Journal of Environment and Ecology
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• v.27 no.1
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• pp.85-98
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• 2013

In order to propose effective conservation management plan, this study verified ecological characteristics, humanities and Social characteristics. The research site is private property which is owned belonging to the Kim's of Gimhae that have long history. The study site is more than a thousand years old and was created for protecting from typhoon. There held the religious ritual what is called Dongsinje until 1960s. There have been protected and managed by the villagers. As the results of analysis, the area of windbreak are $12,392.69m^2$. The windbreak is dominated old years deciduous broad-leaved tree such as Zelkova serrata, Celtis sinensis, Aphananthe aspera. Around there were farmlands(52.1%), urbanized area(26.3%), forest area(16.6%). The vegetation communities of windbreak were classified by considering the dominant species and current status of forest. The forest types are following as; A. aspera community(I) which is using less pressure, Platycarya strobilacea-Carpinus coreana-Z. serrata community(II). Z. serrata community(III) which is using high pressure, Z. serrata-A. aspera community(IV), Z. serrata community(V) which is damaged under canopy trees. The windbreak was in good condition whereas, there were concerns the some wrong status was being undermined such as the wrong forest restoration projects in the past, the trails that is penetrating inside the forest, building up education facilities. Therefore, in order to restore the value of windbreak what is so called Suwol forest, we should improve the problems of forest ecosystem such as wrong management, forest fragmentation by facilities and decline in forest by lack of growing the next generation trees. In addition, we should remove excessive resting facilities and lead to passive use of forest. to improve the way of wrong management, moreover, we should close off he trails that is penetrating inside the forest for improving fragmentation. We should restore vegetation restoration and fostering the next generation trees for forest ecosystem. In order to restore unique of histo-cultural and ecological forest landscape, the next generation trees should be grown up that is the dominant species in Suwol forest. Moreover, as a results of comparing the between good vegetation communities and damaged vegetation communities, it is necessary to complementary planting for demeged vegetation communities, therefore there needs to 10.8 under canopy trees, 79.7 shrubs.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.4 no.1 s.6
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• pp.43-56
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• 2005

This research has examined a time series analysis(TSA) of an every hour traffic information such as occupancy, a traffic flow, and a speed, a statistical model of a surveyed data on the traffic fundamental diagram and an expand aspect of a traffic jam by many Parts of the traffic flow. Based on the detected data from traffic accidents on the Cheonan-Nonsan high way and events when the road volume decreases dramatically like traffic accidents it can be estimated from the change of occupancy right after accidents. When it comes to a traffic jam like events the changing gap of the occupancy and the mean speed is gentle, in addition to a quickness and an accuracy of a detection by the time series analyse of simple traffic index is weak. When it is a stable flow a relationship between the occupancy and a flow is a linear, which explain a very high reliability. In contrast, a platoon form presented by a wide deviation about an ideal speed of drivers is difficult to express by a statical model in a relationship between the speed and occupancy, In this case the speed drops shifty at 6$\~$8$\%$ occupancy. In case of an unstable flow, it is difficult to adopt a statistical model because the formation-clearance Process of a traffic jam is analyzed in each parts. Taken the formation-clearance process of a traffic jam by 2 parts division into consideration the flow having an accident is transferred to a stopped flow and the occupancy increases dramatically. When the flow recovers from a sloped flow to a free flow the occupancy which has increased dramatically decrease gradually and then traffic flow increases according as the result analyzed traffic flow by the multi regime as time series. When it is on the traffic jam the traffic flow transfers from an impeded free flow to a congested flow and then a jammed flow which is complicated more than on the accidents and the gap of traffic volume in each traffic conditions about a same occupancy is generated huge. This research presents a need of a multi-regime division when analyzing a traffic flow and for the future it needs a fixed quantity division and model about each traffic regimes.

• Economic and Environmental Geology
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• v.54 no.2
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• pp.233-245
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• 2021

Many studies on the microstructures in rocks have been conducted using experimental methods with various equipment as well as natural rock studies to see the development of microstructures and understand their mechanisms. Grain boundary migration of mineral aggregates in rocks could cause grain growth or grain size changes during metamorphism or deformation as one of the main recrystallization mechanisms. This study suggests improved ways regarding the analog material experiments with reformed equipment to see sequential observations of these grain boundary migration. It can be more efficient than the existing techniques and carry out an appropriate microstructure analysis. This reformed equipment was implemented to enable optical manipulation by mounting polarizing plates capable of rotating operation on a stereoscopic microscope and a deformation rig capable of experimenting with analog materials. The equipment can automatically control the temperature and strain rate of the deformation rig by microcontrollers and programming and can take digital photomicrographs with constant time intervals during the experiment to observe any microstructure changes. The composite images synthesized using images by rotated polarizing plates enable us to see more accurate grain boundaries. As a rock analog material, norcamphor(C7H10O) was used, which has similar birefringence to quartz. Static grain growth and simple shear deformation experiments were performed using the norcamphor to verify the effectiveness of the equipment. The static grain growth experiments showed the characteristics of typical grain growth behavior. The number of grains decreases and the average grain size increases over time. These case experiments also showed a clear difference between the growth curves with three temperature conditions. The result of the simple shear deformation experiment under the medium temperature-low strain rate showed no significant change in the average grain size but presented the increased elongation of grain shapes in the direction of about 53° regarding the direction perpendicular to the shearing direction as the shear strain increases over time. These microstructures are interpreted as both the plastic deformation and the internal recovery process in grains are balanced by the deformation under the given experimental conditions. These experiments using the reformed equipment represent the ability to sequentially observe changing the microstructure during experiments as desired in the tests with the analog material during the entire process.

• Journal of Environmental Impact Assessment
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• v.30 no.1
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• pp.35-48
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• 2021

In this study, the assessment of field applicability of in-situ remediation of nitrate-contaminated groundwater located in Yesan-gun was performed. Zero-valent iron/bio composite media injected PRB (Permeable Reactive Barrier) and monitoring well were installed in the contaminated groundwater site and monitored main remediation indicators during the PRB operation. Nitrate, nitrite, ammonia, Fe ion, TOC, and turbidity were analyzed and the diversity and population of microorganism in the PRB installed site were investigated for the verification of effect of injected PRB. In the study site where is an agricultural area, a river flows from west to east that forms a river boundary and the southern area has an impermeable sector. It was found that nitrate flows into the river, which is similar as groundwater flow. Simulation result for the fate of nitrate in groundwater showed steady state of nitrate arrived after 3~5 years passed. However, it is just to consider current conditions with no additional input of contaminant source, if additional input of contaminant source occurs contamination dispersion and time for steady state are expected to be increased. The monitoring results showed that Fe ion, TOC and turbidity in groundwater were not clearly changed in concentration after PRB installation, which indicates adaptability of the injected PRB for remediation of groundwater with no additional harmful effect to water quality. The concentration of nitrate maintained less than 5mg/L until 42 days after PRB installation and recovered its initial concentration after 84 days passed and showed termination of reactivity of injected zero-valent iron/bio composite media for removal nitrate. Nitrite and ammonia ions found after installation of PRB indicates reductive removal of nitrate. And the outstanding increase of microorganism diversity and population of Betaproteobacteria Class which includes denitrification microorganism explains biologically reductive removal of nitrate in injected PRB.

• Korean Journal of Ecology and Environment
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• v.54 no.1
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• pp.24-38
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• 2021

Microhabitat In the upper stream is created by various environment variables such as the bottom substrate and the physicochemical factors, and may influence the distribution of benthic macroinvertebrates. We investigated the bottom substrate and environmental variables influencing the distribution of benthic macroinvertebrate in 26 stream-type waterways established at upper reaches of Geum River. During study period, total 85 families, 160 species, 9305 individuals of benthic macroinvertebrates were recorded. The stream-type waterways, where the bottom substrates consist mainly of pebble (16~64 mm) and cobble (64~256 mm) or with rapid water velocity (more than 0.2 m/s) and high dissolved oxygen (more than 120%), were supported by high species diversity of benthic macroinvertebrate. Hierological cluster analysis and the nonparametric multidimensional scale (NMDS) divided 26 stream-type waterways into a total of three clusters. In Cluster 1, the invertebrate species, such as Branchiura sowerbyi, Cloeon dipterum, Ischnura asiatica, Paracercion calamorum, and Radix auricularia, closely related to aquatic macrophytes, and Chironomidae spp., Limnodrilus gotoi, and Tanypodinae sp. were abundant in waterways, with high coverage of silt and clay as well as high turbidity and total nitrogen. The benthic macroinvertebrate species (Cheumatopsyche brevilineata, Drunella ishiyamana, Dugesia japonica, Ephemera orientalis, Gumaga KUa, Macrostemum radiatum, Potamanthus formosus, Semisulcospira libertine, Stenelmis vulgaris, and Teloganopsis punctisetae) included in Cluster 2 were dominated in sites with high cover rates of pebble and gravel. Cluster 3 was predominantly covered by the Cobbles, was supported by Simulium sp. Such a clear distinction in the study sites means that each stream-type waterways is governed by a clear habitat environment. In the case of some sites with low species diversity, improvement measures are required to restore nature, such as improving the function of inflows and outflows, creating meandering channel, and inducing the settlement of littoral vegetation.