• Title/Summary/Keyword: Nature stream restoration

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Flood Stage Analysis and Prediction of River Bed Change for Stream Corridor Restoration Model with River Vegetation (하천식생 복원모형의 홍수위 분석과 하상변동 예측)

  • Song, Joong-Geun;Kim, Byeong-Chan;Lee, Jong-Seok
    • Proceedings of the Korea Contents Association Conference
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    • 2009.05a
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    • pp.437-441
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    • 2009
  • The modern times is as special as from the river, the river is very important of our life. The importance to preserve the river environment has been issued and the river developing method is being changed to use potential function of nature as well as flood control. Essential element of the river restoration is a vegetation. The flow resistance by vegetation along the river banks is greatly increase the flood stage. Therefore, the flow resistance due to vegetation in the river and roughness coefficient changes to understand the hydraulic characteristics is an important elements in the river restoration. The purpose of this study is to analyze the flood stage and the aspects of riverbed changes due to the corridor restoration with river vegetation. In order to simulate the flood stage and riverbed changes, HEC-RAS, RMA-2, and SED-2D model were applied for the upstream and downstream in study reaches, respectively.

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Investigation of Changes in Fluvial Landforms in the Yeoju Reach of the Han River by the Han River Restoration Project (한강살리기사업에의한 한강 여주 구간의 하천 지형 변화 고찰)

  • Kim, Jong Yeon
    • Journal of The Geomorphological Association of Korea
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    • v.27 no.2
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    • pp.29-46
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    • 2020
  • In this study, changes in the fluvial landforms of the Yeoju section of the Han River, which was made up of the Han River Restoration Project, were examined through existing previous research data, government's environmental impact assessment data, satellite images, and field observations. For example, In the vicinity of Dori Island, the most upstream part of the study section, the location of the confluence of the Han River and Cheongmi Stream was changed, and it was found that a significant portion of the sand sedimentary layer disappeared. In the Bawuinupgubi area, the wetland, which is the first class in the ecological nature, was greatly modified, and the elevation of the ground rose as Gangcheon island and it was completely separated from the river by dredging The confluence of Geumdangcheon and the point bar of Yeonyang-ri in the south were also dredged, turned into an artificial waterfront park, and a chute channel remained in the form of a wetland was also developed as a recreational park. The deposional forms around Baekseok-ri islands also disappeared as dredging was carried out. Among the areas adjacent to the confluence of Bokcheon and Yangchon-ri Island, some sedimentay forms remains, but the abandonned channel between Yangchon-ri and the northern river bank has been changed into a riverside reservoir through dredging and embankment construction, and the waterway of the tributary river(Yazoo) has been greatly changed.

A Study on the Construction Methods and the Distribution of Proper Spatial Function for Restoring Urban Streams into Close-to-Nature Streams - A Case Study of Hongjecheon(Stream) in Seodaemun-Gu, Seoul - (도시 내 자연형 하천 조성을 위한 적정 공간기능 배분과 조성방안 연구 - 서울시 서대문구 홍제천을 사례로 -)

  • Jung, Tae-Jun;Lee, Kyong-Jae;Han, Bong-Ho
    • Journal of the Korean Institute of Landscape Architecture
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    • v.41 no.3
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    • pp.43-55
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    • 2013
  • The purpose of this study is to propose a plan that properly organizes urban close-to-nature streams by evaluating the city park functions, ecological functions and landscape functions required for urban stream and setting up space function suitable for the space. The site of this study is Hongjecheon located in Seodaemun gu of Seoul City, whose length of channel spans 6.12km in total. The plan for the construction of close-to-nature streams had been established from late 2003, and the construction was completed. Evaluation Categories and indications were deduced from 4 stages. First, based on theoretical examination, we made a list of stream and park evaluation categories and added Category about Characteristic of urban streams. Next, we set Final Evaluation Categories and indications through the process of goal-relevance, indication verification, merging similar category. Final Evaluation Categories were deduced such as usage demand, usability(city park functions), biodiversity, inhabitation potential, rarity(ecological functions), historical cultural elements, and landscape Quality(landscape functions). As a result of allotting space functions, zones 1 through 4, got high grades at usage demand, was classified as a civic resort district; zones 5 through 6, close to major green area and remained original landscape, as ecological conservation and restoration district; zones 7 through 8, get high grades at usage demand and usability, as environmentally-friendly use district; and zones 9 through 10, many historical cultural elements and view points, and high green possession rate, as stream scenic district. In addition, detail space function and construction plan for each zones were proposed. As a result of this study, proposed space function assignment considering natural characteristics, humanities and social characteristics and landscape characteristics and is expected to be utilized at reasonable spatial planning considering various functions required for urban stream.

Application of Close-to Nature Revetment Techniques Adapted to Low Flow Channel & Monitoring of Vegetation Restoration - Case Study for Hakyoul in the Yangjaech'on - (도시하천에서 자연형 저수로 호안공법의 적용과 식생복원 모니터링 - 서울시 양재천의 학여울 구간을 사례지역으로 -)

  • 최정권
    • Korean Journal of Environment and Ecology
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    • v.11 no.2
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    • pp.210-213
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    • 1997
  • This study for development of close-to nature revetment techniques is conducted to rehabilitate disturbed stream ecosystem. For this objective, the experimental reach as on-site dimonstrated research was set up in Hakyoul, the Yangjaech'on from Oct. 1995 to Nov. 1996. Special emphasis on the developing process of the design of revetments was given to geomorphic character of 3 types of low flow channel bank: point bar, attack point and shallow bay. Each revetment was developed with the consideration on revegetation of emergent plants. And designed techniques were applied to the experimental reach, and were evaluated with monitoring for 1 year. As a result of the process, the experiment suggested ecological alternatives to enhance technical feasibility and to replace the conventional river-work.

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Application of Three-Dimensional Model to Evaluate Stream Discharge Capacity due to Vegetation (식생분포에 따른 하도의 통수능 검토를 위한 3차원 모형의 적용)

  • Noh, Joon Woo;Lee, Jin Young;Ahn, Ki Hong
    • Journal of Environmental Impact Assessment
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    • v.20 no.1
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    • pp.37-48
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    • 2011
  • Recently, the social and environmental functions of nature river are important due to the increase of expectation for river restoration. So it should be considered the effect of vegetation affecting the conveyance capacity and hydraulic resistance. However, it has not yet proposed a objective standard and modeling method to estimate the effect of conveyance capacity according to vegetaion distribution in the watercourse such as water level or velocity. Therefore, this study simulates the variations of water level and velocity using 3-dimensional hydrodynamic model, EFDC, to consider a conveyance capacity in downstream of the Soyang Reservoir. The simulation results were validated using statistical index such as F-test and T-test. As results, the water level rises about 0.01 to 0.47m and velocity difference are about -0.95m/s to 0.23m/s.

Analysis on Fluvial Geomorphological Characteristics based on Past and Present Data for River Restoration: An Application to the Miho River and the Naesung River (하천 복원을 위한 과거 및 현재 자료 기반의 하천지형학적 특성 분석: 미호천과 내성천을 중심으로)

  • Lee, Chan Joo;Kim, Ji Sung;Kim, Kyu Ho;Shin, Hyoung Sub
    • Journal of Korea Water Resources Association
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    • v.48 no.3
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    • pp.169-183
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    • 2015
  • As a basic work for river restoration, analysis on fluvial geomorphological characteristics is made using past and present data to understand close-to-nature geomorphic status. The Miho and the Naesung Rivers are targets of this study. Fluvial geomorphic variables including valley-floor width, sinuosity, bankfull width, channel gradient, bed material size, bankfull discharge and unit stream power are evaluated with dominant processes. Though common sand-bed rivers with similar catchment area, the Miho and the Naesung Rivers are different in terms of valley-floor width, channel shape variables and dominant processes related with longitudinal location. In addition, analyses on interrelationship among the geomorphological variables are carried. Bankfull width is shown to be proportional to bankfull discharge, as is in a rough agreement with the previous studies. Relationship of bankfull discharge and channel gradient shows meandering and braiding are prevalent in the Miho River, whereas the most of the sub-reaches of the Naesung River fall to braiding. Relationship of channel gradient with width-depth ratio indicates dune-ripple processes are dominant in the Miho River, while the Naesung River shows longitudinal diversity from braiding in the downstream sub-reaches to riffle-pool and plane-bed along the upper ones. Analyses based on the past data on a river in a close-to-nature status are thought to be rather reasonable in comparison with those on the same river in a engineered condition.

A Study on the Nature-friendly Management Regarding the User Pattern of Yangjae Stream (양재천의 이용특성을 고려한 환경친화적 관리방안에 관한 연구)

  • Kim Sun-Hee;Hong Suk-Hwan;Bae Jung-Nam
    • Korean Journal of Environment and Ecology
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    • v.18 no.3
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    • pp.306-315
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    • 2004
  • Yangjae stream, stretching through Seocho-gu and Gangnam-gu, is a representative city stream with its environmentally friendly stream makeover project model, launched in 1995. The district of Gangnam-gu, the subject of this study, is under high pressure from the residents for its use as a huge residential areas close to the stream. The study has two main purposes. The first is to identify the condition and characteristic of utilization of Yangjae stream which is currently being increased in use by the stream restoration. Secondly, the study aims to suggest the environment-friendly management to accomplish arrangement of the naturally friendly stream based on the identification survey, The result from the user survey with 303 valid answer sheets show that the people from neighboring residential areas use this stream a lot doing exercising(51.8%) and taking a walk(24.4%) in their free time. Also regular use rate is high, and people are likely to use it alone(30.4%) or as a family(28.4%). With regard to the need of facility increase, even though the respondents required resting places in the shade(80.8%) most, overall, additional introduction of facilities was analyzed as unnecessary(78.8%). safety issue(22.0%) and a lack of convenience facilities(17.6%) and resting places in the shade(16.6%) are pointed as main problems while the users are generally satisfied(59.5%) with the stream. Improving walk-way and planting trees for shade on the slope were designed as a solution for these problems. For securing safety through improvement of walk-way, the scattering of pressure of current walk with building new walk using berms was presented. In order to increase safety on the walk-way(see above figure), the study proposes to build a new walk-way with berms to disperse excessive pressure. It also suggests the tree planting to provide shade in the stream and to make a provision for the planting of forest trees in the current law.

Naturalness Assessment of Riverine Wetland by Vegetational Prevalence Index (식생우세도 지수에 의한 하천습지의 자연도 평가)

  • Chun, Seung-Hoon;Ko, Shin-Hye;Ahn, Hong-Kyu;Chae, Soo-Kwon
    • Journal of Wetlands Research
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    • v.13 no.3
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    • pp.535-545
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    • 2011
  • This study was carried out to suggest the baseline data necessary for vegetation restoration by naturalness assessment of riverine wetland within stream corridor. We selected stream reach both of near nature and urbanized by Nonsan stream and Hongchun river as experimental site. Composition of vegetation community and land use pattern between two sites indicated considerable difference, which imply for many different watershed property and process disturbed each other at river ecosystem. Naturalness of the sampled reaches showed that near nature is in better condition for riverine wetland than urbanized of all two sites. However, the prevalence index of Hongchun river within its natural state was lower than that of Nonsan stream, because the index included some vegetation communities occurred at upland fringe and bank slope. In conclusion assessment system using prevalence index would be considered an effective method for evaluating of natural states of riverine wetland.

Cultural Landscape of Saegumjeong Area as a Recreation Place of Scholars in Joseon Dynasty (조선시대 선비들의 행락공간으로서 세검정 일대의 문화경관)

  • Lee, Jaei;Sung, Jong-Sang;Son, Yong-Hoon;Kim, Tae-Gyun
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.34 no.2
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    • pp.75-86
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    • 2016
  • The area surrounding Segeomjeong, one of the famous pavilions near the capital in the Joseon Dynasty, was a favorite place of scholars to visit and enjoy the beautiful natural landscape. The recreational culture of Segeomjeong area in traditional societies representing the prototype of urban tourism in modern society indicates cultural landscape which is a combination of the surrounding landscape and human activities. At this point, the purpose of this research on Saegumjeong area as a recreation place was to examine recreational activities and landscape elements before restoration. Through the relevant historical literature, there were several recreational activities such as traveling to enjoy scenery, taking a view of stream with waterfalls, doing creative writing of reciting poems and drawing about the greatness of nature and gathering on a broad and flat rock or Tangchundae. Also, the main landscape elements-such as Saegumjeong, stream, broad and flat rocks, pine trees, Tangchundae Peak, and mountains-were extracted through paintings of Saegumjeong drawn before restoration. Consequently, in this study, it was confirmed that the Segeomjeong area was the spot that scholars visited consistently, the center for travel, and the place for communication between scholars and national banquets. This study is significant, in that it drew conclusions on the cultural landscape of the Korean people through the ages and helped to discover the meaning and value of cultural landscape of recreation places based on Korean natural characteristics and cultural climate.

Analysis and Prediction for Spatial Distribution of Functional Feeding Groups of Aquatic Insects in the Geum River (금강 수계 수서곤충 섭식기능군의 공간분포 분석 및 예측)

  • Kim, Ki-Dong;Park, Young-Jun;Nam, Sang-Ho
    • Journal of the Korean Association of Geographic Information Studies
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    • v.15 no.1
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    • pp.99-118
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    • 2012
  • The aim of this study is to define a correlation between spatial distribution characteristics of FFG(Functional Feeding Groups) of aquatic insects and related environmental factors in the Geum River based on the theory of RCC(River Continuum Concept). For that objective we had used SMRA(Stepwise Multiple Regression Analysis) method to analyze close relationship between the distribution of aquatic insects and the physical and chemical factors that may affect their inhabiting environment in the study area. And then, a probabilistic method named Frequency Ratio Model(FRM) and spatial analysis function of GIS were applied to produce a predictive distribution map of biota community considering their distribution characteristics according to the environmental factors as related variables. As a result of SMRA, the values of decision coefficient for factors of elevation, stream width, flow velocity, conductivity, temperature and percentage of sand showed higher than 0.5. Therefore these 6 environmental factors were considered as major factors that might affect the distribution characteristics of aquatic insects. Finally, we had calculated RMSE(Root Mean Square Error) between the predicted distribution map and prior survey database from other researches to verify the result of this study. The values of RMSE were calculated from 0.1892 to 0.4242 according to each FFG so we could find out a high reliability of this study. The results of this study might be used to develop a new estimation method for aquatic ecosystem with macro invertebrate community and also be used as preliminary data for conservation and restoration of stream habitats.