• Journal of Microbiology and Biotechnology
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• v.17 no.11
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• pp.1805-1810
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• 2007

Purple nonsulfur bacteria were isolated from river sediments and their growth promoting capabilities on tomato were examined. Isolated strains KL9 and BL6 were identified as Rhodopseudomonas spp. by 16S rDNA sequence analysis. Rhodopseudomonas strain KL9 maximally produced 5.56 mM/min/mg protein and $67.2\;{\mu}M/min/mg$ protein of indole-3-acetic acid (IAA) and 5-aminolevulinic acid (ALA), respectively, which may be one of the mechanisms of plant growth enhancement. The germination percentage of tomato seed, total length, and dry mass of germinated tomato seedling increased by 30.2%, 71.1%, and 270.8%, respectively, compared with those of the uninoculated control 7 days after inoculation of strain KL9. The lengths of the root and shoot of germinated seedling treated with 3 mM tryptophan, a precursor of IAA, increased by 104.4% and 156.5%, respectively, 7 days after inoculation of strain KL9. Rhodopseudomonas KL9 increased 123.5% and 54% of the root and shoot lengths of germinated seedling, respectively, treated with 15 mM glycine and succinate, precursors of ALA. This plant growth promoting capability of purple nonsulfur bacteria may be a candidate for a biofertilizer in agriculture.

• Journal of Korean Society on Water Environment
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• v.28 no.2
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• pp.238-246
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• 2012

Organic matters budget in Lake Hoengseong were monthly investigated from April 2009 to November 2009. The intense rainfall occurred at between July and August and the hydrological factors were highly varied during the rainfall season. By the concentrated rainfall, the elevation, influx and efflux were sharply increased and the turbid water was also flowed into the middle water column in Lake. The inflow of turbid water increased the nutrient concentrations in water body and this appears to stimulate of phytoplankton regard as the primary productivity of influx of organic matter. Monthly average concentration of dissolved organic carbon (DOC) was generally higher than the particulate organic carbon (POC) concentration in Lake, but Temporal and spatial variation of POC concentration was higher than DOC and the maximum POC concentration was recorded in surface water in August, had the highest phytoplankton biomass. Organic carbon concentration in inflow site was rarely changed during the dry season, but the concentration was rapidly increased by the initial intense rainfall. In organic matters budget, the most of the organic matters was inflowed from the inflow site at rainfall season. Especially, the influx of allochthonous organic matters during the intense rainfall was 72.4% in the total influx organic matters.

• Journal of Environmental Science International
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• v.24 no.3
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• pp.275-280
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• 2015

In order to measure the Radionuclides and Concentration, the directly grinded land samples (river soil, pine leaves and mugwort) among the environment samples around the nuclear power plant were filled in a 450 mL Marinelli beaker and weighed to obtain the dry mass ratio of the samples. Then the background and land samples were measured for 80,000 sec. The analysis of the collected land samples showed that most of them contained less radiation nuclide than the detection minimum limit in the 'Ministry of Education, Science and Technology Public Notice No. 2010-32.'In others, the natural radionuclides $^{40}K$ were detected. Of the products of nuclear reaction discharged by a nuclear reaction, $^{134}Cs$ and $^{137}Cs$ are more easily detected, and their discharge sources can be traced using the relative ratio. Although the radioactive concentration in the vicinity of Kori Nuclear Power Plant, which is more than 1,100km away from Fukushima, the Japanese nuclear accident site, continuous monitoring is needed as the radionuclides can still be accumulated in the soil or animals and plants.

• Journal of the Korean Institute of Landscape Architecture
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• v.28 no.5
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• pp.39-47
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• 2000

This study is to investigate the conditions closely related to the establishment of vegetation in the riparian zone: the soil condition, an important factor along with climate and light. Especially, the soil structure of the microtopographical formations in the specific area known as the riparian microtopographical zone investigated. In addition, the effect of the riparian microtopographical features on the ground water level, soil moisture content, and vegetation was studied. The results of this study are as follows; 1) At all sample sites, below the sand layer, a gravel layer is always present. This is the result of past floods. 2) Although Salix koreensis experiences frequent disturbances such as increase in river level and floods, this vegetation establishes itself in the most secure are in the microtopographical zone. 3) The growth of Phragmites japonica is closely related to the underground water level. 4) It is clear that Miscanthus sacchariflorus grows concentrated in dry areas. 5) The soil accumulation conditions differ according to the soil moisture content of each microtopgraphical feature. Accordingly, the moisture content of the soil is clearly different within the microtopographical zone. The continuous and long-term investigation and research on the relation of riparian reproduction and the relevance with location surrounding factors are necessary in the future.

• Journal of Conservation Science
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• v.12 no.1 s.15
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• pp.26-30
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• 2003

We examined the species of charcoals excavated at the late paleotithic site of Suyanggae. Suyanggae is located on the riverbed of Han river near Banyans, central Korea. The charcoals belong to the post-glacial period (radiocarbon dates: $18,630\~16,400\;BP$). Only two species were identified. Most of samples (139 among 142) examined were Pinus spp. (diploxylon). The other 3 samples were Picea spp. The results suggest the upper layer at $235\~245\;cm$ below the ground level was formed during dry and warm post glacial period, predominated by two needle pines and lower layer at 270 cm below the ground layer during the last glacial maximum period, predominated by spruces.

• Environmental Engineering Research
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• v.15 no.4
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• pp.191-195
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• 2010

This study was carried out to investigate the important factors relating to runoff and pollutant loads in a plot unit located in an agricultural area. Of the precipitation parameters, such as total precipitation, days since last rainfall (ADD, the rainfall was more than 10mm) and average rainfall intensity on runoff, the strongest effect was obtained due to total precipitation, but the rainfall intensity showed a slightly positive correlation. It was expected that both variables, i.e. total precipitation and rainfall intensity, would lead to the generation of greater runoff. In contrast, runoff was negatively correlated with ADD, which is understandable because more infiltration and less runoff would be expected after a long dry period. The TSS load varied greatly, between 75.6 and $5.18{\times}10^4g$, per event. With the exception of TN, the TSS, BOD, COD and TP loads were affected by runoff. The correlations of these items were proportional to the runoff volume, with correlation coefficients (r) greater than 0.70, which are suitable for use as NPS model data. The TSS load showed very good relationships with organics (BOD & COD) and nutrients (TN & TP), with correlation coefficients greater than 0.79. Therefore, the removal of TSS is a promising factor for protecting water basins.

• Journal of Korean Society on Water Environment
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• v.22 no.2
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• pp.349-357
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• 2006

Nowadays, the discharges of urban streams during dry season are depleted because the hydrologic cycle in the watershed has been destroyed due to the expansion of the impermeable area, the excessive groundwater pumping, climate change, and so forth. The streamflow depletion may bring out severe water quality problems. This research are to investigate the hydrologic characteristics and to develop a technology to restore sound hydrologic cycle of Anyangcheon watershed. For the hydrological cycle analysis of the Anyangcheon watershed, continuous simulations of urban runoff were performed for the upstream basin of Gocheok bridge whose basin area covered 4/5 of the whole catchment area. The increase of impervious area by urbanization was analysed and its effect on urban runoff was evaluated. The SWMM 5 (Storm Water Management Model 5) was used for the continuous simulation of urban runoff. The analysis results of urbanization effect on runoff are as follows: the surface runoff in 2000 increases to 65% of the whole precipitation whereas the surface runoff in 1975 amounts to 50% of the precipitation; the groundwater runoff in 2000 amounts to 7% and shows 6% decrease during the period from 1975 to 2000.

• Magazine of the Korean Society of Agricultural Engineers
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• v.34 no.3
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• pp.43-52
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• 1992

Design low flows were derived from the decision of a best fitting probability distribution and of an optimum transformation method can be contributed to the planning of water utilization and management of various hydraulic structures during dry season in the main river systems in Korea. The results were analyzed and summarized as follows. 1.Basic statistics for the selected watersheds were calculated as one of means for the analysis of extremal distribution. 2.Parameters for the different frequency distributions were calculated by the method of moment. 3.Type m extremal distribution was confirmed as a best one among others for the frequency distribution of the low flows by x$^2$ goodness of fit test. 4.Formulas for the design low flows of the Type m extremal distribution with two and three parameters were dervied for the selected watersheds. 5.Design low flows for the Type m extremal distribution when a minimum drought is zero or larger than zero were derived for the selected watersheds, respectively. 6.Design low flows of the Type m extremal distribution with two parameters are appeared to be reasonable when a minimum drought approaches to zero and the observed low flows varied within a relating small range while those with three parameters are seemed to be consistent with the probability distribution of low flows when a minimum drought is larger than zero and the observed low flows showed a wide range.

• Journal of Environmental Impact Assessment
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• v.22 no.4
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• pp.329-343
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• 2013

According to previous studies, the increased air temperature can lead to change of thermal stratification structure of lakes and reservoirs. The changed thermal stratification may result in alteration of materials and energy flow. The objective of this study was to predict the effect of climate change on the water temperature and stratification structure of Daecheong Reservoir, located in Geum River basin of Korea, using a three-dimensional(3D) hydrodynamic model(ELCOM). A long-term(100 years) weather data set provided by the National Institute of Meteorological Research(NIMR) was used for forcing the 3D model. The model was applied to two different hydrological conditions, dry year(2001) and normal year(2004). It means that the effect of air temperature increase was only considered. Simulation results showed that the surface water temperature of the reservoir tend to increase in the future, and the establishment of thermal stratification can occur earlier and prolonged longer. As a result of heat flux analysis, the evaporative heat loss can increase in the future than now and before. However, the convective heat loss and net long wave radiation from water surface decreased due to increased air temperature.

• The Journal of Engineering Geology
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• v.23 no.2
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• pp.117-125
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• 2013

Flooding of riparian groundwater caused by changes in rainfall patterns has become a critical problem in areas of agricultural and arable land. Therefore, quantitative analysis of direct runoff and baseflow, which are the most important factors in determining the flow rate of a river, is required to clarify the flooding mechanisms of riparian groundwater. In this study, baseflow obtained using the WHAT system of hydrograph analysis based on Web GIS, and baseflow measured from direct runoff were quantitatively analyzed. Baseflow during the rainy season was 0.489 $m^3/s$ on 17 July 2012, 0.260 $m^3/s$ on 18 July 2012, and 0.279 $m^3/s$ on 19 July 2012, while that during the dry season was 0.006 $m^3/s$ on 6 March 2013 and 0.009 $m^3/s$ on 30 March 2013. The results show that an increase in baseflow occurred during the rainy season in the alluvial area of a riparian zone, and that the measurement error was less during the dry season than during the rainy season.