• The Korean Journal of Quaternary Research
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• v.16 no.2
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• pp.9-21
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• 2002

In Korea, many open-air upper palaeolithic sites are located at the river valley, particularly exposed in gently rotting terrain along the river course. They are situated at an altitude less trail 30 m above present river bottom, and covered with the blankets of slope deposits of several meters in thickness. The purpose of this research is to eluridate depositional and vegetational environment of the alluvial upper palaeolithic Jangheung-ri sites on the basis of analytical properties of grain size population, chronology, palynology, soil chemistry and clay mineralogy and magnetic susceptibility of the Jangheung-ri Quaternary formations. The lithostratograpy of Jangheung-ri sit is subdivided into 3 layers based on the depositional sequence and radiocarbon ages. From bottom to top, they are composed of slope deposits with lower paleosol layers, young fluvial sand and gravel with backswamp organic muds, and upper paleosol layers. The upper paleosol was formed under rather dry climatic condition between each flooding period. Dessication cracks were prevalent in the soil solum which was filled with secondarily minuted fragments due to pedogenetic process. The soil structure shows typical braided-typed cracks in the root part of cracking texture, and more diversified pattern of crackings downward. The young fluvial sand gravel were formed by rather perennial streams after LGM. The main part of organic muds was particularly formed after 15Ka. Local backswamp were flourished with organic muds and graded suspension materials in the flooding muds were intermittently accumulated in the organic muds until ca. 11Ka. This episode was associated with migration of Nam River toward present course. Organic muds were formed in backswamp or local pond. Abies/Picea-Betula with Ranunculaceae, Compositae, Cyperaceae were prevalent. This period is characterized with B$\Phi$lling, Older Dryas, Allerod, and Younger Dryas (MIS-1). Stone artefacts were found in the lower paleosol layers formed as old as 18Ka-22Ka. Based on the artefacts and landscape settings of the Jangheung-ri site, it is presumed that settlement grounds of old people were buried by frequent floodings of old Nam River, the river-beds of which were heavily fluctuated laterally and river-bed erosions were activated from south to north in Jangheung-ri site until the terminal of LGM9ca 17Ka).

• Journal of Korea Water Resources Association
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• v.56 no.9
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• pp.553-562
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• 2023

The Gobiobotia naktongensis is a species endemic to Korea, and it has recently been designated as a class I endangered species of freshwater fish. Naeseong Stream, one of the tributaries of the Nakdong River, where the Gobiobotia naktongensis was first discovered, provided an optimal habitat for the Gobiobotia naktongensis in the past with fine sand beds and riffle. Currently, due to the construction of Yeongju Dam and the excessive dredging of river channels by the local government, the riverbed armoring in the downstream area of the dam is undergoing rapid changes, and as a result, the habitat environment of the Gobiobotia naktongensis is deteriorating. In this study, the variations of the habitat suitability of the Gobiobotia naktongensis due to the change in the riverbed grain size of the Naeseong Stream were analyzed based on the WUA (weight usable area) using the physical habitat model, River2D. The study domain is the reach from Seoktap Bridge to Hoeryong Bridge downstream of Yeongju Dam. The change in riverbed grain size was analyzed using D50 acquired in 2010 and 2020, respectively. The substrate grain size of Naeseong Stream in 2020 was thicker than that in 2010, and the riverbed coarsening phenomenon was evident overall. As a result of the River2D analysis, the area in which the Gobiobotia naktongensis could inhabit was only about 0.75% in 2010 compared to the entire area of the flow, and even this decreased to 0.55% in 2020 due to riverbed armoring.

• Journal of Korean Society of Water and Wastewater
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• v.9 no.2
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• pp.97-107
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• 1995

Today a conventional water treatment system has many problems. The ozone/GAC process, sometimes termed Biological Activated Carbon(BAC), appeared to be effective for the removal of soluble organic matters in the drinking water. The water quality of Nak-dong river in Pusan, generally shows BDOC 30-40% and NBDOC 60-70%. The pilot plant installed at the Duk-san water works that was been largest treatability(1,650,000ton/day) in Pusan. A experimental water in the pilot plant made use of the water after sand-filteration. Following results are drawn from this study. Initial adsorption velocity($DOC/DOC_o/T$) in the pure adsorption of GAG had a 0.0225, it's velocity changed to 0.006 after ozone added and the optimum ozone dose ranged of $1.4-2.0mgO_3/L$. A experimental water in the pilot plant composed with humic material(78%). Humic material composed with humic acid(20%) and fulvic acid(56%), and it's rate changed to 18 and 50% respectively after ozone added. DOC constantly decreased in the EBCTs and removal efficieny in the 15min of EBCT was 45-50%. It showed the largest removal rate of BDOC in the EBCT 5 and among the season, characteristics of removal varied. The HPC distributed over $10^6-10^7CFU/cm^3$ in the bed depth and among the season, distribution of HPC were differential.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.174-178
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• 2009

하천의 시간유량 혹은 일유량과 같은 연속유량을 획득하기 위해서는 각각 정해진 시각에 유량측정 시행해야한다. 그러나 매시각, 매일 유량측정을 시행하는 것은 경제적으로나 기술적으로 매우 어려운 일이다. 따라서 연속적인 유량자료를 획득하기 위해 수위-유량관계를 작성하고 이를 연속적으로 측정한 수위에 대입하여 유량으로 환산하다. 하상변동이 심하게 발생하지 않는 안정적인 하천에서는 수위-유량관계 또한 시간에 따라 변화하지 않고 안정적인 관계를 유지한다. 다만, 우리나라 대부분의 하천에서는 주요 홍수 전 후로 통제하도의 하상이 변화하기 때문에 일반적으로 2개 혹은 3개 기간으로 수위-유량관계를 분리하여 유량환산에 이용하고 있다. 통제하도가 모래하천인 경우에는 주요홍수 이외에도 지속적으로 세굴 혹은 퇴적이 발생하기 때문에 매 유량측정 마다 서로 다른 수위-유량관계를 나타낸다. 따라서 주요 홍수 전 후로 수위-유량관계를 기간 분리하여 작성한다고 해도 신뢰성 있는 유량자료를 확보하기 곤란하다. 이와같이 불안정한 하도 통제를 받는 지점에서는 매 유량측정시마다 수위-유량관계를 조정하여 유량을 환산하여야 한다. 본 연구에서는 모래하천인 내성천의 향석 지점의 유량측정 성과를 이용하여 수위-유량관계를 개발하고, 매 유량측정시에 측정한 수위와 유량자를 이용하여 수위-유량관계 조정곡선을 작성하였다. 이를 이용하여 수위-유량관계를 조정하여 연속적인 유량환산을 시행하였다. 이 결과 기존 홍수 전 후로 기간 분리하여 작성한 수위-유량관계를 이용한 환산유량과 비교하여 신뢰성 있는 유량자료를 확보할 수 있었다.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.2
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• pp.145-149
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• 2001

This study was performed to evaluate the growth and nodulation characters of hypernodulating soy-bean mutant, SS2-2, and to know the growth and yield performance of the mutant in infertile soil. Soil fertility was adjusted by mixing the different ratios of soil components including clay, river sand, and horticultural bed, which resulted in fertile and infertile soil. Dry weight, nitrogen concentration, and leaf nitrate reductase of each plant were measured around V6 stage (47 days after planting) and around R3 stage (82 days after planting). There were significant effects of soil fertility and soybean genotype on the total dry weights including root, nodule, stem, leaf, and pod dry weight at V6 and R3 stages. Total dry weight of hypernodulating mutant, SS2-2, was clearly less than that of its wild type, Sinpaldalkong 2. However, nodule development on the roots of SS2-2 was much greater than that of Sinpaldalkong 2, regardless of soil fertility. Though SS2-2 was smaller in plant size than Sinpaldalkong 2, genotypic difference in total nitrogen content was not significant at both V6 and R3 stages because SS2-2 fixed more nitrogen biologically than its wild type in the root nodule. The SS2-2 mutant showed lower plant yield in both infertile and fertile soil. The SS2-2 contained more crude seed protein than Sinpaldalkong 2, and was characterized with reduced top and root growth.

• Journal of Korea Soil Environment Society
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• v.3 no.3
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• pp.63-74
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• 1998

In the study, the feasibility of deposit soil in river and stream bed as a subsitute for conventional plant soil was investigated through the analysis of soil characteristics and germination/growth rate for 75 days. Proper mixtures among sediments from various places were compared to optimize the germination and growth rate of plant in the ratio of 2 : 1 and 3 : 1 (sand : deposit). From the results, it could be concluded that the sediment mixed 3 : 1 showed most favorable germination and growth conditions for pansy and the sediment containing enough amount of silt and clay components showed most favorable conditions for marigold. Consequently, the feasibility of sediments as a substitutional plant soil was evaluated to be high, once the sediments were properly mixed for each specific plant.

• The Journal of the Korea Contents Association
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• v.13 no.5
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• pp.485-492
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• 2013

The point sand bars of Hahoi Village on Nakdong River have undergone considerable changes including fluvial and vegetation characteristics due to flood regulation by the dams constructed upstream. In this study, the numerical fluvial/sediment and water quality model, KU-RLMS, is applied to the aquatic area near Hahoi Village (middle/upper region of the Nakdong River) for clarifying the mechanisms of changes in hydraulic and aquatic characteristics. The fixed-bed hydraulic experiment was carried out for horizontal two-dimensional numerical model. The numerical simulation reveals that flow is accelerated near the left bank of Booyongdae downstream of the Hahoi Village area. Circulatory flow pattern was observed at the right bank downstream of Hahoi Village. The simulation was in good agreement with the hydraulic/physical experiment. For the discharge of design flood, at the area of circulatory flow pattern, the superelevation of about 1.0 m at the right bank was predicted compared to the left bank of high flow velocity, which is also in good agreement with hydraulic experiment.

• Journal of environmental and Sanitary engineering
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• v.5 no.1
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• pp.1.1-14
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• 1990

This study was conducted to investigate the contents of heavy metals in soils of the Kumho river basin, by analyzing soils according to the distance from edge of the river and to the soil layers. The contents of heavy metals in soils showed highly in its downstream. Namely there was shown a remarkably high contents of these heavy metals in the Kum-ho bridge areas where Kongdan stream joins Dalseo stream, such as 39.52ppm for zinc, 35.92ppm for copper, 97.90ppm for iron, 102.45ppm for manganese, 13.92ppm for lead, respectively, and 0.48ppm for cadmium. However, the heavy metals contents in soils around Kangchang bridge tended to gradually decrease in its contents, probably because its main soils consisting of sand. Based on their soil layers, the average contents of these heavy metals in the surface soils were higher than one of the subsurface soil. Its contents according to the distance from the river edge indicated some difference every individual area. Nevertheless, its contents showed lower contents in the area far away from the edge. And its contents tended to again increase in the outside bank. In addition, a remarkable positive correlation is shorten between individual heavy metals, except correlation between iron and lead. Also cadmium just shows reverses correlation in the statistics. With respect to comparison between soil layers, there was a remarkable positive correlation between surface layers and subsurface layers. Considering the above results, it seems that the pollution of river bed's soil is in proportion to it of stream.

• Korean Journal of Ichthyology
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• v.27 no.4
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• pp.275-283
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• 2015

Habitat characteristics and feeding ecology of Iksookimia pacifica were investigated in this study to provide baseline data for its ecological characteristics in Bukcheon (stream), Goseong-gun, Gangwon-do, Korea. The main inhabit of I. pacifica was found to be sand bottoms of Bb or Bc river type with slow water flow. Based on studies of their habitat preferences according to age, their preference for sand bed was the same. However, their preference for depth and velocity was different. When their age was increased, their depth preference was also increased ($24.9{\pm}17.61cm$ for 0+ year, $69.6{\pm}30.32cm$ for 1+ year, $82.4{\pm}33.30cm$ for 2+ years, and $90.0{\pm}31.55cm$ for $3+{\leq}$ years). The water velocity was found to be 3.8 ~ 4.0 cm/sec for ages between 0+ and 1+ and 6.0 ~ 7.3 cm/sec for ages between 2+ and $3+{\leq}$. They were active on sand from March to November. They would hibernate in sand during the winter season. During the day from 12 pm to 24 am, they were highly active with high food consumption. Their main food sources analyzed with index of relative importance (IRI) include Chironomidae (76.7%), Simuliidae (10.3%), Rotatoria (7.3%), and Arcellidae (2.2%). Their juveniles (total length 20~40 mm) would feed on small-sized preys such as Rotatoria, Copepoda, and Arcellidae. Older I. pacifica would feed on big-sized preys such as Chironomidae and Simuliidae.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.8
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• pp.683-691
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• 2015

Circulating Fluidized Bed(CFB) combustion has the several advantages which are the fuel flexibility, the economy, the efficiency and the environment. It is necessary to apply a renewable energy to produce electricity due to the Renewable Portfolio Standard(RPS) mandates recently. So, in this study, co-combustion with a coal and a wood pellet was investigated to evaluate the combustibility and the environment as function of blending ratio of them in a Lab-scale CFB reactor. To investigate the characteristics of the co-combustion, the blending ratio which is the weight of wood pellet by the total calorific value of the supplied, was considered. Bed material was a river sand(No. 7). As increasing the blending ratio, the exhausted gas emissions such as CO, NOx, HC and SOx were decreased. But in case of wood pellet over 30%, CO, HC and SOx emission were increased. And the gas temperatures at the downstream were decreased.