• Journal of the Korean Institute of Landscape Architecture
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• v.45 no.5
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• pp.42-59
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• 2017

To investigate rooting and community forming ability, sod strips of Gramineae such as Miscanthus sacchariflorus (Maxim.) Benth., Miscanthus sinensis var. purpurascens(Andersson) Rendle, Imperata cylindrica var. koenigii(Retz.) Pilg., and Arundinella hirta(Thunb.) Tanaka were planted horizontally at a width of 10~15cm in October 2010 on the bank slope of Kwangju Stream in Korea. Seeds of each species were sown in April 2010 in plastic seedbeds(60cm length ${\times}$ 30cm width ${\times}$ 5cm depth) filled with 4cm of garden soil and grew until October 2010 to form rectangular sod, which then was cut into multiple strips(20cm length ${\times}$ 6cm width ${\times}$ 4cm root depth). Weeds growing on the experiment sites were removed twice a year until those four species had formed a community by 2013. Weeds were not eradicated during 2014 and 2015 to observe whether the community formation can be maintained without weed removal. t-tests on stem numbers and heights in May, July, and September were conducted between 2013 and 2014, and between 2014 and 2015. Stem numbers and heights of the four species in 2014 were significantly decreased(p<0.001) compared with those in 2013 due to weed damage to their growth in 2014. Stem numbers and heights of Miscanthus sacchariflorus(Maxim.) Benth., Miscanthus sinensis var. purpurascens(Andersson) Rendle, Imperata cylindrica var. koenigii(Retz.) Pilg. in 2015 were similar to those in 2014(p>0.05). Stem numbers and heights of Arundinella hirta(Thunb.) Tanaka in 2015, however, were significantly reduced compared with those in 2014(p<0.001) due to weed impact on its growth. After three years of weed removal, a community of each species was formed. Miscanthus sacchariflorus(Maxim.) Benth., Miscanthus sinensis var. purpurascens(Andersson) Rendle, Imperata cylindrica var. koenigii(Retz.) Pilg. were able to establish communities without any further weed removal. Arundinella hirta(Thunb.) Tanaka, however, was not able to maintain its community due to considerable damage to its growth caused by weeds even after three years of weed removal. Miscanthus sacchariflorus(Maxim.) Benth., Miscanthus sinensis var. purpurascens(Andersson) Rendle, Imperata cylindrica var. koenigii(Retz.) Pilg. are more suitable to sod strip plantings on stream bank slopes in terms of the maintenance of community formation without weed eradication. t-test on stem numbers and heights each September during the five year experiment period between sod strip planting and potted plants of the four species were conducted. Stem numbers of strip sod plantings were significantly higher(p<0.001) than those of potted one. Heights of strip sod plantings, however, were significantly lower(p<0.05) than those of the potted samples. Therefore, strip sod planting is more advantageous regarding bank slope erosion protection due to the higher number of stems.

• Magazine of the Korean Society of Agricultural Engineers
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• v.24 no.2
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• pp.49-55
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• 1982

The purpose of this study is to classify the factors influenced on the damages of head works suffered from the storm flood occurred on July 22 1980 in both Musim and Bochong rivers and to find out an integral counter measures against the causes influenced on the disaster of head works in the engineering aspect of planning, design, construction and maintenance. In this survey, number of samples was taken 25 head Works, and the counter measures against the causes of their disasters summarized was as follows, 1. In the aspect of planning a. As the flood water level after the establishment of head works is more increased than the level before setting of head works owing to having more gentle slope of river bed between the head works than nature slope of river bed. Number of head works should be reduced for the appropriate annexation of them b. In the place where head works is established on the curved point of levee, the destruction of levee becomes severe by the strong deflective current. Therefore the setting of head works on the curved point should be kept off as long as possible and in case of unavoidable circumstances the construction method such as reinforced concrete wall or stone wall filed with concrete and anchored bank revetments should be considered. 2. In the aspect of design a. As scoring phenomena at up stream is serious around the weir Where the concentration of strong current is present in such a place, up stream apron having impermeability should be designed to resist and prevent scoring. b. As the length of apron and protected bed is too short to prevent scoring as down stream bed, the design length should be taken somewhat more than the calculated value, but in the case the calculated length becomes too long to be profitable, a device of water cushion should be considered. c. The structure of protected river bed should be improved to make stone mesh bags fixed to apron and to have vinyl mattress laid on river bed together with the improvement for increasing the stability of stone mesh bags and preventing the sucked sand from the river bed. d. As the shortage of cut-off length, especialy in case of the cutoffs conneting both shore sides of river makes the cause of destruction of embankment and weir body, the culculation of cut-off length should be taken enough length based on seepage length. 3. In the aspect of design and constructions a. The overturing destruction of weir by piping action was based on the jet water through cracks at the construction and expansion joints. therefore the expansion joint should be designed and constructed with the insertion of water proof plate and asphalt filling, and the construction joint, with concaved shape structure and steel reinforcement. b. As the wrong design and construction of the weep holes on apron will cause water piping and weir destruction, the design and construction of filter based on the rule of filter should be kept for weep holes. c. The wrong design and construction of bank revetment caused the severe destruction of levee and weir body resulting from scoring and impulse by strong current and formation of water route behind the revetment. Therefore bank revetment should be designod and constructed with stone wall filled with concrete and anchored, or reinforced concrete wall to prevent the formation of water flow route behind the wall and to resist against the scoring and impulse of strong stream. 4. In the aspect of maintenance When the damaged parts occurred at head works the authorities and farmers concerned should find and mend them as soon as possible with mutual cooperation, and on the other hand public citizen should be guided for good use of public property.

• Parasites, Hosts and Diseases
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• v.55 no.1
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• pp.95-98
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• 2017

Fasciola hepatica is a trematode that causes zoonosis, mainly in cattle and sheep, and occasionally in humans. Few recent studies have determined the infection status of this fluke in Korea. In August 2015, we collected 402 samples of freshwater snails at Hoenggye-ri (upper stream) and Suha-ri (lower stream) of Song-cheon (stream) in Daegwalnyeong-myeon, Pyeongchang-gun in Gangwon-do (Province) near many large cattle or sheep farms. F. hepatica infection was determined using PCR on the nuclear ribosomal internal transcribed spacer 2 (ITS-2). Among the 402 samples, F. hepatica 1TS-2 marker was detected in 6 freshwater snails; thus, the overall prevalence in freshwater snails was 1.5%. The prevalence varied between collection areas, ranging from 0.0% at Hoenggye-ri to 2.9% at Suha-ri. However, F. gigantica ITS-2 was not detected in the 6 F. hepatica-positive samples by PCR. The nucleotide sequences of the 6 F. hepatica ITS-2 PCR-positive samples were 99.4% identical to the F. hepatica ITS-2 sequences in GenBank, whereas they were 98.4% similar to F. gigantica ITS-2 sequences. These results indicated that the prevalence of F. hepatica in snail intermediate hosts was 1.5% in Gangwon-do, Korea; however the prevalence varied between collection areas. These results may help us to understand F. hepatica infection status in natural environments.

• Journal of Korean Society of Rural Planning
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• v.6 no.1 s.11
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• pp.29-37
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• 2000

The purpose of this study was to propose section designs for the ecological improvement of streams in rural villages in Korea. According to the survey about ecological conditions of rural streams of 10 selected rural villages (sep., 1996), the streams could be classified into three divisions(upstream, inner village, downstream), and the average width of streams was 9m, and the height of banks 3.1m. The slopes of basin were 7.33%, 2.67%, 1.39% at upstream, inner village, downstream respectively. The survey about the residents' usage of stream and the preferred activities(jun., 1997) showed that the streams were most frequently used for the supply of agricultural water use(39%), for the washing(15%) and for the recreation and rippling(10%), etc.. Three standard designs were presented for upstream, inner village, and downstream, and three standard sections were made by each designs. For the upstream division, it was designed to be used for the recreational activities in summer and the major stream bank materials were base rock and existing boulders with least artificiality. As the streams in the residential area were expected to be frequent access and used by the residents, most facilities for the streamside activity such as waterfront, water holes, shallows, walk were concentrated in this part with some artificiality. The downstream was designed for the agricultural activities such as water supply, space for the preparation of work and some break during the work.

• Korean Journal of Environment and Ecology
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• v.18 no.1
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• pp.61-74
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• 2004

The study was to investigate and compare plants and frequency of appearing species of vegetation transect in a straight and a restoration Section of Bulgwang stream in Seoul. Some part of Bulgwang stream was restored as a closed-to-nature stream. This present study consists of two investigations, the first investigation being conducted on May and the second one on August -September 2003. Based on the analysis of the data collected from both investigations, this study classified and listed all of the plants appeared in a straight and a restoration section of the stream. The study used the Belt-transect method in order to examine and analyze discover the appearance frequency of the vegetaton transect per 200 meters. During the period of the first investigation and the second one, plants of 33 families, 73 classes, and 88 species appeared in the straight section, while plants of 36 families, 76 classes, and 90 species appeared in the restoration section. The Naturalized Index of the straight section was 22.7％, and that of the restoration section was 21.1％. As shown on the results indicating that the Urbanization Index of the straight section was 7.8％, and that of the restoration section was 7.4％, the Urbanization Index of the straight section was slightly higher than the restoration section. The results using belt-transect analysis method showed that in case of the straight section, the plants of the highest appearance frequency on the riverside were Persicaria hydropiper and Humulus japonicus. On the contrary, in the case of restoration section, the plants showing a higher appearance frequency on the riverside were identified as Salix gracilistyla, Persicaria hydropiper, Rumex crispus, and Humulus japonicus. In conclusion, there was no difference between the straight and the restoration section in the bank with regard to vegetation transect. However, a remarkable difference was found on the riverside for the Salix gracilistyla which was introduced in the restoration section.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.5
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• pp.135-147
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• 2018

The objective of this study was to analyze the characteristics of combined 1D/2D inundation simulation of riverside farmland using the Hydrologic Engineering Center - River Analysis System (HEC-RAS). We compared and analyzed inundation simulation results between 1D and combined 1D/2D hydraulic simulation using HEC-RAS. Calibration and validation of stream stage were performed using three rainfall events. The coefficient of determination ($R^2$) and root mean square error (RMSE) between simulated and observed stream stage were 0.935 - 0.957 and 0.250 m - 0.283 m in calibration and validation, respectively. The inundation area showed no significant difference in 1D and combined 1D/2D simulation ($8.48km^2$ in 1D simulation, $8.75km^2$ in combined 1D/2D simulation). The average inundation depth by 1D simulation was 1.4 m deeper than combined 1D/2D simulation. In the lower inundation depth, the inundation area by combined 1D/2D simulation was larger than inundation area by 1D simulation. As the inundation depth increased, the inundation area by 1D simulation became wider. In the case of the 1D/2D combined simulation, low elevation areas along the river bank were inundated widely. Compared to 1D/2D combined simulation, the flood radius in some sections was longer in 1D simulation. In the 1D analysis, because the low altitude riverside farmlands are also assumed to stream, it is calculated that riverside farmlands have the same stage as the mainstream when the stream is overflowed. Therefore, the inundation area seems to be overestimated in those sections. In other regions, the inundation areas tend to be broken depending on overflow by each stream cross-section. In the case of river flooding, the overflow is expected to flow to the lower area depending on the terrain, such as the results of the combined 1D/2D simulation. It is concluded that the results of combined 1D/2D inundation simulation reflected the topographical characteristics of low-lying farmland.

• Animal Systematics, Evolution and Diversity
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• v.27 no.3
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• pp.246-261
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• 2011

Adult chironomid collections were carried out near Namdae stream located at Jeollabuk-do, Muju-gun, Mujueup, Dangsan-ri in 2008 and 2009. Among 21 species of the tribe Tanytarsini identified from Muju collections, six new species (Cladotanytarsus neovanderwulpi, Paratanytarsus paramikesecumdus, Rheotanytarsus parapentapodus, Rheotanytarsus sungili, Tanytarsus neotamaoctavus, and Tanytarsus synyunosecundus) and four previously unrecorded species (Cladotanytarsus vanderwulpi, Paratanytarsus inopertus, Tanytarsus tamagotoi, and Tanytarsus uresiacutus) were confirmed. They are fully described with illustrations. As a result of this report, the Korean fauna of Tanytarsini consists of 37 species, 6 genera. In total, 128 species, 52 genera, 5 subfamilies of the family Chironomidae are listed in Korea.

• Journal of Korea Water Resources Association
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• v.30 no.1
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• pp.15-22
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• 1997

The flow in meandering channel has a great influence on curved bank revetment in river morphology. It is difficult to state generalized cirteria for channel improvement applicable to any paricular river. But it is very important to provide some principles and guidelines for design engineers. The objective of this experimental study in fixed bed model is to povide effective data that find out maximum velocity size by the mean velocity and the radius of curvature in curved channel, for the purpose of improving small stream without hydraulic modeling test each time.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1464-1468
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• 2007

The restoration project of Cheonggyecheon was conducted to creates the refreshing water-friendly environment in the downtown Seoul. It already have passed almost 2 years after restoration. This project changed environment of Cheonggyecheon dramatically, so historic hydrological data became useless. There are not so many hydrological data to manage and control this newly restored urban stream. The main purpose of this study is collecting and analysing the hydrological data of Cheonggyecheon. At first, we analysed the mechanism of Cheonggyecheon discharge using the sewage design maps and some GIS data. We also monitored the water levels and discharges of 5 main points of Cheonggyecheon. Rating curves of these 5 points were derived. There were 249 blocks of water gates which were located at both sides of bank. We also monitored the behaviors of these water gates. Through the these monitorings, some equations were derived to give useful information to the manager of Cheonggyecheon.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.11 no.3
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• pp.74-86
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• 2008

To assessment the disturbances of the Namgang caused by dam construction, upstream area was selected for the reference reach and downstream area was selected for the comparison reach. And these reaches were surveyed and analyzed according to the assessment criteria of the river disturbances.The artificial factors of river disturbances were classified as river improvement works, dam construction and aggregate dredging. The indexes were physical factors as like epifaunal (bottom), embeddedness, velocity/depth regime, sediment deposition, channel flow status, channel alteration, frequency of riffles, bank stability, vegetative protection, riparian zone etc.The assessment results showed 46% of the assessment criteria which was serious status in dam downstream area and 89.5% of it which was excellent status in dam upstream.Finally, the results showed that physical river environment in downstream area was disturbed by the discharge control and the interception of sediment discharge by dam, consequently this disturbance give rise to impact of ecosystem in river.