• Ecology and Resilient Infrastructure
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• v.2 no.4
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• pp.324-329
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• 2015

For the restoration of lateral connectivity between rivers and floodplains, it is important to find the isolated former floodplain (IFF) and to characterize its land use in Korean rivers which were channelized by levee constructions for flood protection. The aim of this study is to map the IFF and to assess its land use pattern in the Nakdong River, Korea. The isolated former floodplain was explored by being overlapped on a digital elevation model (DEM), digital topographic map and design flood level using a geographical information system (GIS) in the Nakdong River basin. The land use of the identified IFF was classified by land-use map. The total number of IFFs was 384 and their total area was $291km^2$. While IFFs were usually surrounded by mountain forest in the upper river area, they tended to be located on wide plain areas in the downstream area of Nakdong River. The land use pattern of IFFs was mostly farmland (73.9%) and urban areas (12.7%) in the river. The results of delineation and land use analysis of isolated former floodplain in the Nakdong River will be used as a base line data for planning stream restoration.

• Journal of Wetlands Research
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• v.16 no.2
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• pp.213-220
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• 2014

Recently, river maintenance is change due to concern for the environment increases. Thus, the river restoration and river environment is best part of river maintenance. In case of Korea, existing river is improvement straightly for flood control and transportation. When the stream channel is straightly, maintain stability is important. Thus, construction of levees along the river. The various river structures for the purpose of flood control and transportation are inhibit factors of longitudinal and lateral connectivity. Connectivity is defined as the maintenance of lateral, longitudinal, and vertical pathways for biological, hydrological, and physical processes. Long-term point of view, increased connectivity is very important for a healthy ecosystem composition. As the first step of river restoration, this study described theory and concept of river continuum and the numerical model was applied to a real topography to simulate the flow analysis with or without segregated and blocked space in the Mankyung river. The results of this study can be utilized to develop the watershed connectivity assessments methods in order to the river restoration.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.817-820
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• 2008

The river environments of many streams in korea have been deteriorate through the rapid industrialization and urbanization since the 1960s. In korea, on the other hand, much efforts on the research and project have been made for the restoration of the deteriorated streams to close-to-nature. in order to restore the deteriorated streams, therefore, it is necessary to investigate such advanced technologies and materials. In view of this requirement, various research paths are being taken focusing on coarse aggregates to make multi-functional porous concrete having continuous voids so as to improve water and air permeability, acoustic absorption, water purification and applicability to vegetation. The Purpose of this study is to investigate the method for recovery of the environment in the streams area using porous concrete retaining wall block. the multi-P.O.C block applies for test in the Jangduri-cheon have been monitored planting, stability etc. after 6 months, plant grows flourishing and reconstructed in state such as nature rivers.

• Korean Journal of Environment and Ecology
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• v.21 no.5
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• pp.390-399
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• 2007

We analyzed the vegetation environment at the stream section of habitat in which Cottus koreanus lives. The plant communities were classified into Fraxinus rhynchophylla community, Acer ginnala-Salix koreensis community, Phragmites japonica-Salix gracilistyla community, Salix gracilistyla community, Phragmites japonica community, Robinia pseudo-acacia community, and Oenanthe javanica-Persicaria thunbergii community. The frequency of Phragmites japonica-Salix gracilistyla community was the most. And also the frequencies of Fraxinus rhynchophylla community and Salix gracilistyla community were high. In stream bank zone and terrace zone, the typically represented vegetation was the Fraxinus rhynchophylla community and Acer ginnala-Salix koreensis community and Phragmites japonica-Salix gracilistyla community, respectively. The rNCD of the top-priority plants applied to restoration of the vegetation in stream bank zone came out by the order of Ulmus davidiana var. japonica, Salix koreensis, Acer ginnala, Salix gracilistyla, and Fraxinus rhynchophylla. The rNCD in terrace zone was arranged by the order of Salix gracilistyla, Phragmites japonica, and Artemisia princeps. The spatial distribution of vegetation was the most greatly influenced by cross-sectional position of the surveyed stream, and this aspect is believed to be due to the habitat's physical stability. Species diversity also obviously makes a great difference depending on their surrounding physical stability.

• Ecology and Resilient Infrastructure
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• v.10 no.2
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• pp.40-49
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• 2023

To reduce the damage of extreme flooding caused by climate change and to create flood mitigation sections in a nature-friendly riparian area, it is necessary to restore the floodplain area by referring to the past floodplain section of the current inland waterfront area before the levee was built. This study proposed a method of selecting a location for floodplain restoration using old maps of the Geum River study section and analyzed the effect of flood level reduction through unsteady flow numerical simulations using the floodplain as a flood mitigation space. As a result of analyzing changes in the river areas using old maps, the river section was estimated to gradually reduce by 27.8% (1,059,380 m²) in 2020 compared to 1919, and it was found to have an effective storage capacity of 2,200,868 m³ when restored to offline storage. The flood level and discharge control effects analyzed based on HEC-RAS unsteady flow simulation were 16 cm and 219.01 m³/s, respectively, in the downstream cross-section. In the numerical simulation in this paper, the flood mitigation space was applied as an offline reservoir. The effect of reducing the flood level may differ if levee retreat/relocation is applied.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.3B
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• pp.283-296
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• 2008

The Urban Stream Assessment Technique (USAT) was suggested to give information about present urban stream condition. Domestic and foreign stream evaluation methods were analyzed and some streams were previously investigated to decide evaluation factors that could evaluate stream condition and have concern with characteristics and flood control of urban stream. The USAT consisted of three steps. High step has three characteristics concerned with functions of stream such as flood risk, stream, and ecology. In middle step, three characteristics were subdivided by ten features to describe changes and degradations of urban stream. Low step consisted of fifty three factors that explain the present condition of ten features. A survey of river experts was conducted to reflect weight among characteristics and features. The weights were calculated by analytic hierarchy process(AHP). The USAT was carried out to check over application of that in Suwon, Anyang, and Joongrang stream. The results of stream evaluation were expressed by factor index, feature index, characteristic index, total index, and evaluation grade. The results of the USAT were useful to realize changed and degraded areas. It is expected that the USAT can be used as base investigation for restoring and managing urban streams.

• Ecology and Resilient Infrastructure
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• v.3 no.1
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• pp.70-75
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• 2016

The purpose of this study was to develop water-purification vegetation mats consisting of the eco-friendly materials and to validate their water purification capabilities with the objective of reducing nonpoint pollution into streams. The developed vegetation mats are made of coconut fiber shell and filling consisted of zeolite, diatomaceous earth or a mixture of calcinated foam media. The bench scale assessment of the water purification capability of the three filling materials showed that the removal efficiencies of suspended solid (SS), total nitrogen (T-N) and total phosphorus (T-P) were higher in the foam media than in zeolite or diatomaceous earth. From the results of the field experiment, the removal efficiencies of the vegetation mats filled with the foam media were 60.1% in SS, 32.2% in T-N and 20.2% in T-P. Therefore the vegetation mats filled with the foam media calcinated from zeolite and diatomaceous earth should have higher efficiencies in controlling the nonpoint source pollutions in streams.

• Journal of Wetlands Research
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• v.14 no.3
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• pp.413-418
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• 2012

In this study, both habitat use analysis by rumen contents of Eurasian river otter (Lutra lutra) were carried out to investigate the preference of habitat environment and diet using their fecal samples. As the target sites, two streams (the Naechon-cheon and the Koonup-cheon) were selected in the upstream of the Hongcheon river, Hongcheon County, Gangwon Province. A total of 478 track samples (e.g., feces, scent and footprint) were found during the survey periods (May to November, 2009 and November, 2010). The dominant points, where the tracks of river otters were observed, were areas with the low depth(0.5-1m) and the slow flow velocity (5m/sec). Also, both rocks and rock-beds were preferred but artificial facilities were avoided. This ecological study of river otters using habitat use analysis and diet analysis by rumen contents will be useful fundamental information to conserve the river otter populations, and to protect their habitats.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.485-490
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• 2009

강원도의 약 89%가 산지로 되어 있기 때문에 강원지역 주민의 거주지는 대부분 홍수 피해를 강하게 받는 계곡이나 하천변에 잡고 있으며 매년 반복되는 홍수의 피해 위험이 높다. 따라서 홍수 시 생활공간을 보호하기 위한 제방의 안전성을 확보하는 것은 강원도의 하천관리에서 가장 중요한 점이다. 호안공법은 일반적으로 하천의 생태계나 경관적인 측면에서 부정적인 경우가 많은 인공시설물이기 때문에 최근에는 자연과 어울리는 친자연형 호안공법을 추구한다. 본 연구는 강원도 내 1개 국가하천 6개 지점, 214개 지방하천 2,760개 지점에 대한 하천 호안공법의 종류, 식생상태, 하천특성, 호안파괴 특성 등을 조사하고 하천호안공법 적용 하천특성과 호안공법, 식생 등의 관계를 분석하여 강원도형 호안공법 개발의 기초자료를 제공하는 데 목적이 있다. 강원도에 설치된 호안공법은 망태형, 붙임형, 블록형, 쌓기형, 옹벽형으로 구분할 수 있으며, 영동지역은 망태형 25%, 옹벽형 20.1.%, 블록형 18.3%를 차지하고 있으나 영서지역 하천은 쌓기형 32.9%, 망태형 19.2%, 옹벽형 16.6%를 나타내고 있다. 두 지역에서 옹벽이 16%이상을 차지하는 것은 하천경사가 급하고 만곡 수충부가 많아 홍수 시 구조적인 안정성이 큰 옹벽을 통한 호안보호에 따른 것으로 판단된다. 옹벽을 제외하면 하천평면이 호안공법 선택에 큰 영향을 미치지 않은 것으로 보이며 오히려 하천경사나 하천재료 특성이 반영된 것으로 판단된다. 호안파괴의 원인은 홍수 시 하상의 세굴이다. 그러나 옹벽호안은 국부적인 하상세굴에도 콘크리트 구조특성으로 쉽게 파괴되지는 않는 것으로 판단된다. 보 하류지점에 설치된 돌망태 호안은 하상저하와 보에 의한 유향변동으로 발생된 강한 수충현상에 의해 파괴되는 것으로 조사되었다. 호안의 식생 활착은 블록형, 망태형, 쌓기형 호안의 순으로 양호한 것으로 나타났다. 망태형이나 쌓기형 호안은 영동지역보다는 영서지역에서 높은 식생 피복도를 나타냈으며, 이는 하천의 경사와 호안의 침수빈도와 관계가 큰 것으로 판단된다. 식생블록형 호안은 지역 구분 없이 식생피복도가 높고 하천경사나 재료특성에도 불구하고 강원도의 하천호안공법으로 우수한 기능을 한다. 시급히 식생을 도입하고자 하는 경우 식생블록형 호안이 추천되며 호안공의 안정성과 식생의 다양성 측면에서는 망태형 호안공법이 추천된다.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.2033-2037
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• 2008

최근 들어 국지성호우와 장마, 태풍에 의한 자연재해는 모든 분야에서 심각한 영향을 미치고 있다. 자연재해로 발생한 토사는 하천, 농업용 저수지, 댐 및 하구를 메워 흐름을 방해하고 저서생태계에 미치는 영향은 매우 크다. 이러한 토사는 농업용 저수지와 홍수 조절용 구조물의 사용 수명을 단축시키고, 하상을 높여 흐름을 방해하거나 변화시켜 하천 범람을 발생하기도 한다. 한편 하천범람과 제방 붕괴 등은 농지 침수는 물론 작물의 성장을 방해하는 등 많은 경제적 손실을 가져오고 있다. 본 연구에서는 토사의 농도와 분광반사특성의 상호관계를 알아보기 위하여 분광복사계(Li-1800)를 이용하여 미리 제작한 수조 안의 토사(실트질, 모래질) 농도를 변화시켜 토사농도에 따른 분광반사 특성을 파악하고, 그 특징에 대해 검토, 고찰하였다. 연구결과 실트질의 체적반사율이 모래에 비해 약 40% 높게 나타났으며, 실트와 모래 모두 $554{\sim}588nm$영역에서 최대반사율을 나타내었다. 상관분석 결과 각 토사의 상관계수는 실트질이 $0.63{\sim}0.99$, 모래가 $0.73{\sim}0.96$의 값을 나타냈으며, 두 토양 모두 $550{\sim}900nm$영역에서 r>0.90의 높은 상관성을 보였다. 또한, 토사농도에 따른 반사특성은 실트질의 경우 토사 농도가 $0{\sim}60%$까지 $470{\sim}740nm$영역에서 큰 상승폭을 보인 반면, 모래의 경우 토사농도가 25%까지 크게 증가하였으나 30%이상의 농도에서는 변화 폭이 매우 적어지는 특징을 보였다. 토사농도의 변화에 따른 탁수의 분광 반사특성은 토사의 종류에 따라 크게 다르다는 것을 확인할 수 있었다.