• Title/Summary/Keyword: 물길

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Impact on Fish Community by Restoration of Ecological Waterway using Physical Habitat Simulation (물리서식처 분석을 통한 생태 물길 복원이 다양한 군집종에 미치는 영향)

  • Choi, Heung Sik;Choi, Jonggeun;Choi, Byungwoong
    • Ecology and Resilient Infrastructure
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    • v.6 no.1
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    • pp.1-11
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    • 2019
  • This study performed the impact of ecological waterway on fish community in a reach of the Dal River, Korea. Fish monitoring revealed that 9 fish species are dominant, namely Zacco platypus, Coreoleuciscus splendidus, Zacco koreanus, Pungtungia herzi, Acheilognathus yamatsutae, Rhinogobius brunneus, Tanakia signifer, Gobiobotia macrocephala, and Pseudopungtungia tenuicorpus, and account for 95% of the total fish community. The River2D model was used for the computation of the flow and the HSI model for the habitat simulation. The restoration of the waterway performed through the small dam removal, the formation of the pool-riffle structure, and the change of the bed elevation and width. Simulation results indicated that the restoration of the ecological waterway effects significantly increased by about 16% for the WUA (Weighted Usable Area) of the total fish community in optimal ecological flow conditions ($Q=7.0m^3/s$). The restoration of the ecological waterway is more advantageous to fish community.

Nasolacrimal Duct Obstruction after Radioactive Iodine Therapy for Thyroid Cancer (갑상선암에서 방사성 요오드 치료 후 발생한 코눈물길 폐쇄)

  • Hwang, Moon Won;Lee, Eung;Yang, Jae Wook
    • Journal of The Korean Ophthalmological Society
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    • v.55 no.1
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    • pp.1-6
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    • 2014
  • Purpose: To investigate the clinical manifestation of nasolacrimal duct obstruction after radioactive iodine therapy for thyroid cancer. Methods: The authors examined 622 patients who were treated with radioactive iodine therapy after the operation for thyroid cancer from January 2009 to December 2011. Fourteen patients (18 eyes) were diagnosed nasolacrimal duct obstruction based on the lacrimal irrigation test, lacrimal probing test and dacryocystography in our oculoplastic clinic. We analyzed the dose of radioactive iodine therapy, number of treatments, clinical manifestation and treatment type by retrospectively reviewing the patients' medical records. Results: The mean radioactive iodine dose ($215.7{\pm}23.1mCi$, p = 0.01) and the mean number of treatments ($1.36{\pm}0.50$, p < 0.001) were significantly greater in 14 patients who had nasolacrimal duct obstruction than in patients who did not. The average onset of tearing symptoms occurred 10.2 months after radioactive iodine therapy. The mean time between correct diagnosis and therapy was 18.4 months. Three patients (3 eyes) had occlusion at the common cannaliculus and 11 patients (15 eyes) had occlusion at the nasolacrimal duct. Ten patients (13 eyes) underwent endonasal dacryocystorhinostomy for complete obstruction and 4 patients (5 eyes) underwent silicone tube intubation for partial obstruction. Conclusions: Nasolacrimal duct obstruction is a rare complication associated with radioactive iodine therapy for thyroid cancer, thus, clinicians should be aware of this complication and refer patients with symptoms of epiphora to the oculoplastic department for specialized evaluation and treatment.

Impact on Habitat Changes by Restoration of Low-Flow Channel using Physical Habitat Simulation (물리서식처 모의를 통한 저수로 물길 조성이 서식처 변화에 미치는 영향)

  • Choi, Jong Geun;Kim, Jong Joo;Choi, Heung Sik
    • Proceedings of the Korea Water Resources Association Conference
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    • 2019.05a
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    • pp.107-107
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    • 2019
  • 하천은 과거부터 현재까지 인간의 삶에 있어서 중요한 공간이며 환경적, 생태적으로도 중요한 가치를 지니고 있다. 특히, 하천은 물과 흙으로 이루어져 있기 때문에 수생물이 살아갈 수 있는 독특한 생태 서식처 공간을 제공한다. 국내에서는 1980년대 말부터 하천환경의 개선 및 복원에 대해 관심과 인식을 높이고 공감대를 형성하여 훼손된 하천을 원래 모습으로 되돌리는 사업을 수행하였다. 이러한 하천복원사업이 하천에 서식하는 수생물의 어떠한 영향을 주는지 분석하기 위해 최근에는 다양한 물리서식처 분석이 수행되고 이를 통해 각종 복원계획을 수립하고 있다. 하천복원사업을 통한 생태유량 재산정, 보 철거의 영향, 다양한 복원기법을 통한 수생물에 미치는 영향 파악 등을 들 수 있다. 그러나 이러한 기존 연구들은 하천복원사업으로 인한 수리특성과 수생 서식처의 변화를 살펴보는 간접적인 영향에 대한 내용이었다. 그러나 직접적으로 영향을 미치는 하도의 단면을 재설계하고 다양한 복원기법을 적용하여 그 영향을 파악하는 연구도 수행되어야 할 것으로 판단된다. 본 연구는 수리학적으로 유리한 저수로 물길 조성 및 다양한 저수로 조성기법의 적용을 통해 우점종의 서식처에 미치는 영향에 대해 원주천을 대상으로 물리서식처 분석을 수행하였다. 대상구간은 원주천 중 상류에 위치한 900 m 구간으로, 대상 어종은 원주천의 중 상류에 서식하는 우점종인 참갈겨니를 목표로 하였다. 수리분석과 서식처분석은 각각 River2D 모형과 서식처 적합도 모형을 사용하였다. 서식처 적합도 모형에 사용된 서식처 적합도 곡선은 Gosse (1982)의 방법을 이용하여 구축하였으며, 수심, 유속, 기층을 모두 고려하여 물리 서식처 분석을 수행하였다. 저수로 물길 복원 조성을 위하여 수리학적으로 유리한 저수로 단면으로의 복원 및 거석, 여울/소 구조, 단면의 확폭을 통해 기존 자연형 하천과는 다른 복원을 조성하였다. 수리학적으로 유리한 저수로 물길 복원을 조성한 결과를 이용하여 물리서식처 분석을 수행하였을 때, 기존 자연하천인 현상태 대비 약 37% 가중가용면적이 악화되는 것으로 나타났다. 그러나 수리학적으로 유리한 저수로 단면의 설계 조건에서 거석, 여울/소 구조 및 단면의 확폭의 복원을 수행하였을 때 서식처가 최소 약 3%에서 최대 21%까지 가중가용면적이 향상되었다.

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A Case Study of the Habitat Changes due to the Restoration of Low-Flow Channel (저수로 물길 복원을 통한 서식처 공간 변화 연구)

  • Choi, Jonggeun;Choi, Heung Sik;Choi, Byungwoong
    • Ecology and Resilient Infrastructure
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    • v.6 no.1
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    • pp.58-68
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    • 2019
  • This present study conducted the impact of the restoration of low-flow channel on fish habitat in a reach of the Wonju Stream, Korea. The target species were Zacco koreanus, a dominant species in the middle- and upper-stream of Wonju Stream. The River2D model was used for the computation of the flow and the habitat suitability index model was used to estimate the quantity and quality of fish habitat using habitat suitability curves. In order to restore the study area, the low-flow channel was identified through the bankfull discharge of the study reach, and the best hydraulic section was designed. In addition, various restoration techniques were applied to the low-flow channel through rocks, pool/riffle structures, and the change of the channel width. Simulation results indicated that the restoration of the best hydraulic section effects decreased habitat suitability for the target species. However, when various restoration techniques were applied, the WUA (Weighted Usable Area) was improved by about 11%.

A Study on the Characteristics of Planning of Hwa-sung from the Point of Water System (수체계로 본 수원화성 건설의 계획적 특성에 관한 연구)

  • Kang, In-Ae
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.29 no.4
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    • pp.137-147
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    • 2011
  • This study aims to find out the construction process and planning characteristics of Suwon and Hwa-sung in 18th century from the point of water system. This study has an explanatory approach. The planning intents in the water system was driven out by analyzing various planning elements in relation to water system in the process of constructing Hwa-sung in 18th century. Using Entire Map of Hwa-sung, land registration map made in 1911 and topographic map of 1/10,000 scale made in 1917, water system and interpretation of spatial structure in Hwa-sung were analyzed. The results are as follows(Planning characteristics of the water system in Haw-sung in 18th century are as follows). Firstly, in determining the spatial structure and location of Hwa-sung, water system had an important role. Secondly, integrated drainage system was planned by the organization of natural and artificial water stream. Thirdly, the main street system and land use structure were planned in relation with water system. Fourthly, territoriality of main area was planned with water stream. Fifthly, ponds were constructed for flood control and they had important role as landscape elements. Sixthly, water stream was used as intentional BiBo element. As a result of the study, the weater system of Hwa-sung in 18th century was planned by the organization of natural and artificial water stream in relation with the location of new town and wide area's spatial structure, street system, land use structure, territoriality of main area, terriflood control, water quality protection, landscape, 비보 and urban daily life.

Wind and Bathymetry Effects on the Fresh Water Plume Structures (담수 확산에 미치는 바람과 해저 지형의 영향)

  • Lee, Jungwoo;Yun, Sang-Leen;Oh, Hye-Ceol
    • Journal of Korean Society of Environmental Engineers
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    • v.36 no.10
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    • pp.698-703
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    • 2014
  • The structures of fresh water plume depending on estuarine geometries and wind directions (upwelling, onshore, downwelling, and offshore winds) were studied using the Regional Ocean Modeling System (ROMS). Four idealized estuaries, which are different in bathymetry, were considered. The results showed that the fresh water plume was restricted close to the shore line where a river was connected to the sloping shelf rather than the flat shelf due to the fast momentum exchanges from x, y to z momentums on the sloping shelf. Mild upwelling and offshore winds (${\mid}{\tau}_{\omega}{\mid}=0.01Pa$) enhanced stratification on the contrast to previous studies which showed that winds destroyed stratification by enhanced vertical mixing. However, downwelling and onshore winds had similar effects on the vertical structure of the fresh water plume as in previous studies enhancing vertical mixing. The plume was confined above the underneath submarine channel, thus the plume path was directly affected by the direction of the submarine channel on the shelf.