• 제목/요약/키워드: levees

검색결과 113건 처리시간 0.022초

배내천 中流의 底棲性 大形無脊椎動物에 대한 硏究 (A Study on the Benthic Macroinvertebrates in the Middle Reaches of Paenae Stream , a Tributary of the Naktong River , Korea 2 . Comparison of Communities and Environments at the Upper and Lower Sites of Levees)

  • Oh, Yong-Nam;Tae-Soo Chon
    • The Korean Journal of Ecology
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    • 제14권4호
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    • pp.399-413
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    • 1991
  • Benthic macroinvertebrate communities and environments at the upper and lower sites of levees in the middle reaches of paenae stream, a tributary of the naktong river,were investigated in four seasons from August 1989 to may 1990. Current velocities were significantly fast at the loer sites than the upper sites of levees. Substratum compositions were also different between these two sites. Abundances of major species of benthic macroinvertebrates occurring in four seasons were primarily dtermined by temperature. in each location of levees, however, current velocities and substratum particle sizrs were important in determining species were generally higher than upper sites of levees. Biological indices were also high at the lower sites of levees. diversity, evenness and dominance indices were positively correlated with the quantity of the middle-sized large pebbles(3∼5cm in diameter) in stream bed.

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Distribution of Meiobenthic Arthropod Communities in the Hyporheic Zone of Nakdonggang

  • Lee, Chi-Woo;Park, Jong-Geun
    • Journal of Species Research
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    • 제5권1호
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    • pp.157-165
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    • 2016
  • The hyporheic zone is an ecologically important area for investigating habitat biodiversity. However, only few studies have been conducted on this aspect in Korea. This study aimed to investigate the distribution of arthropod communities in the hyporheic zone of Nakdonggang River between 2012 and 2013. The meiobenthic arthropod communities found in the hyporheic zone were identified using a stereomicroscope and classified into 9 taxanomic groups. The abundance of arthropod communities was higher in the hyporheic zones of streams having well-formed sandbanks and gravelly areas. The arthropod communities found along the Nakdonggang River differed depending on the conditions of levees and the regions of the river from where they were collected. The frequency of species of the order Harpacticoida was high in the Nakdonggang main stream and western downstream region. The abundance of species belonging to Cyclopidae was high in the upstream region, midstream region, and eastern downstream region of the river. The frequency of species of the order Bathynellacea was high in the riverside parks or cement levees, but that of species belonging to Cyclopidae was high in the natural levees and gabion levees. Our findings suggested that arthropod communities preferred natural levees.

신소재 활용 제방의 월류 붕괴 경감 효과 분석 (Analysis of Breach Mitigation Effect on Levee made with New Substance by Overtopping)

  • 고동우;강준구
    • 한국산학기술학회논문지
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    • 제19권2호
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    • pp.1-8
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    • 2018
  • 최근 전 세계적으로 이상기후에 따른 국지성 폭우로 인한 홍수 발생과 하천제방의 노후화로 인하여 제방이 소실되고 저지대에서의 엄청난 재산 피해 및 인명 피해가 발생되고 있다. 특히 월류에 의한 제방붕괴는 약 40%에 달하는 것으로 보고되고 있다. 본 연구는 월류에 의한 제방붕괴의 원인 및 메커니즘을 파악하기 위해 수리모형실험을 수행하였고 제방의 내구성 향상을 위한 친환경 신소재인 바이오폴리머를 이용하여 월류에 따른 제방사면의 안정성 및 붕괴지연효과 등을 평가하였다. 영상계측장치를 이용한 실험분석 결과, 제방사면에 신소재 적용 시 총 제방붕괴시간은 흙 제방과 비교했을 때 약 2.25배의 차이를 보였고 신소재가 적용되지 않은 흙 제방의 경우 초기 붕괴발달속도가 약 1.43배 빠르게 나타났으며 시간이 지날수록 제체가 급격하게 붕괴되는 것을 관찰할 수 있었다. 또한 신소재 적용 제방의 붕괴메커니즘은 흙 제방에 비해 확연히 다르게 나타났으며 월류 흐름에 저항하여 사면침식속도를 경감시킴으로써 급격한 제체붕괴 예방이 가능한 것으로 평가되었다.

관행농업과 유기농업이 논둑에 서식하는 토양배회성 무척추동물에 미치는 영향 (Effects of Conventional and Organic Farming on Ground-dwelling Invertebrates in Paddy Levees)

  • 김명현;최락중;한민수;최순군;나영은;강기경;어진우
    • 한국유기농업학회지
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    • 제24권3호
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    • pp.539-556
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    • 2016
  • This study was conducted to compare the community structure and biodiversity of ground-dwelling invertebrates between conventional and organic paddy fields's levees. Ground-dwelling invertebrates were collected using a pitfall trap every month for two years (2010-2011) in levees of conventional and organic paddy fields. The numbers of species and individuals were higher in organic paddy field than in conventional paddy field. For the pests, the treatment of insecticide and herbicide reduced the number of Delphacidae, and Chrysomelidae, but did not affect the other pests such as Chronomidae, Culicidae, Thripidae, and Aphididae. For the natural enemies, the treatment reduced the number of individuals of most of enemy's taxon (except only one taxonomic group, Ichneumonidae) in the levee of conventional paddy field.

MODEL TESTS ON LEVEES REINFORCED WITH SHEET PILES UNDER HIGH WATER CONDITIONS WITH/WITHOUT SEISMIC LOADING HISTORY

  • Koseki, Junichi;Tanaka, Hiroyuki;Otsushi, Kazutaka;Nagao, Naoya;Kaneko, Masaru
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2010년도 추계 학술발표회 3차
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    • pp.49-54
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    • 2010
  • In order to study the performance of levees reinforced with steel sheet piles under high water condition, a series of model tests was conducted by simulating the high water condition before and after applying severe seismic loading history. As a result, the seepage behavior through the subsoil layers underlying the levee was not significantly affected by the seismic loading history. It was also verified that, irrespective of the seismic loading history, the sheet piles installed at the levee crest or shoulder are effective in preventing the breakage of levees caused by overflow. In addition, applicability of drainage works at the foot of the levee in preventing the seepage failure was confirmed.

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육안점검표 및 스마트폰을 이용한 하천제방 배수통문 육안점검시스템 개발 (Development of Visual Inspection System for Culvert in Levee Using Checklists and Smart Phone)

  • 김진만;조진우;최봉혁;조원범
    • 한국구조물진단유지관리공학회 논문집
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    • 제17권3호
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    • pp.97-107
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    • 2013
  • 배수통문은 하천제방을 횡단하여 설치된 하천시설로, 연속적으로 시공되어져야 하는 제방의 특성에 반하여 불연속적인 단면을 제공함으로써 하천제방 안전성을 저하시키는 구조물로 알려져 있다. 본 논문에서는 배수통문의 효율적인 점검 체계 구축을 위하여 육안점검표 및 휴대용 단말기를 이용한 육안조사 시스템을 제시하고 향후 개선방향을 제시하였다. 제안된 육안점검표는 적용성 평가결과 간단한 육안점검에 의한 손상 파악을 통해 배수통문의 보수 계획 수립과 보수 및 정밀안전진단에 대한 투자우선순위 선정에 적용성이 높은 것으로 평가되었다.

드론영상을 이용한 하천 제방 매핑에 관한 연구 (A Study on Mapping Levees Using Drone Imagery)

  • 정윤재;박현철;최수영
    • 한국수자원학회:학술대회논문집
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    • 한국수자원학회 2018년도 학술발표회
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    • pp.30-30
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    • 2018
  • 제방 매핑 연구는 제방 안전도 측정을 위해 중요하며, 드론 영상은 실시간 제방 지도를 만들기 위해 활용될 수 있다. 본 연구에서는 하천유역을 촬영한 드론 영상을 이용하여 제방 매핑 연구를 진행하였다. 우선 테스트 베드의 하천유역을 촬영한 드론 영상을 수집한다. 그리고 드론 영상을 이용하여 사진측량/영상처리 기법을 기반으로 3차원 디지털 표고모델(DEM)과 정사영상을 제작한다. 최종적으로 수동/자동화 기법을 이용하여 제방 표면에 존재하는 중요한 객체(둑마루, 제방법선, 비탈경사면, 침식지역 등)를 디지털 표고모델과 정사영상으로부터 탐지한다. 추후 연구에서는 드론 영상으로부터 중요한 객체를 탐지할 수 있는 자동화 기술 개발을 목표로 한다.

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Socio-economic and Environmental Impact Assessment in Agricultural Cultivation, Case Studies in Rice Cultivation and Shrimp Farming in the Mekong River Delta, Vietnam

  • Nguyen, Tran Nhan Tanh;Tran, Thi Hong Ngoc
    • 환경영향평가
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    • 제18권6호
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    • pp.461-467
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    • 2009
  • This paper provides two case studies of environmental impacts with socio-economic values. The first case is on flood protection levees conducted from 2003 to 2004 in Phu Tan district, An Giang province. The impacts were found by comparing full flood protection levees area (FFPL) to non-full flood protection levees area (NFFPL). Participatory Rural Appraisal (PRA) tools per each group of rich, middle, and poor people were used to list the impacts. Then, major impacts were selected by ranking and interviewing 60 households per site, and assessed by Cost Benefit Analysis (CBA) in rice production from 1996 to 2002 between two areas. The tested research indicated moving system of NFFPL to that of FFPL lost about 11 million VND/ha/year. The second case is on impacts of Penaeid shrimp farming conducted in Duyen Hai District, Tra Vinh Province in 2004-2005. Ninety households and 12 local officials were interviewed. Four PRAs were conducted and 36 water samples were taken inside and outside shrimp pond to measure values of DO, COD, Fe total, TSS, N-$NO_3{^-}$, N-$NH_4{^+}$, P-$PO{_4}^{3-}$, and Chlorophyll-a. Research results showed only 36.7% of the households got profit from shrimp farming. Highest financial efficiency was 0.72 for the semi-intensive system. Tested water indicators showed surface water quality did not match Vietnamese standard for surface water in coastal area (TCVN 5943-1995) and in rain. The water was very muddy and contaminated by organic aluminum. Summarily, the impacts were clarified more obviously via adding socio-economic values to assessment. Importantly, the values were transformed to household's income which is an indicator for policy-makers to consider the impacts obviously. Besides, data of different group of people impacted are cases contributing to consideration of the impacts in an appropriate social level.