• Title/Summary/Keyword: urban rivers

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Diagnosis of Vegetation for the Ecological Rehabilitation of Streams - The Case of the Namhan River - (하천의 생태적 복원을 위한 식생학적 진단 - 남한강을 중심으로 -)

  • Myung, Hyun;Kwon, Sang-Zoon;Kim, Chang-Hwan
    • Journal of the Korean Institute of Landscape Architecture
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    • v.30 no.5
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    • pp.98-106
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    • 2002
  • This study was designed to present a river model with the aim of restoring the ecosystem and improving the landscape along the urban rivers on the basin of the Namhanl river, a core life channel for the National Capital regin. The revelation of botanical status, transition trend and correlation of plants might lead to providing the urban river restoration projects and ecological river formation projects with basic data for a model of ideal aquatic ecology and landscape. The outcomes of this study could be summed up as follows: 1. The plant communities of river flora found on the basin of the Namhan river could be categorized largely into 39 plant communities 2. Most diverse plants were distributed in the rivers lower reaches such as Unsim-ri where the protected zone of Paldang reservoir for city water borders the body of Jodae swamp where natural streams flow nearby. 3. One of the greatest threats to the biomass of the River Namhan is that the communities of such invasive alien plants as Panicum dichotomiflorum and Ambrosia artemisiifolia var. elatior dominate most parts of the area, a fact that has resulted in a reduced variety of plants and will, sooner or later, be likely to cause an ecological imbalance in the hitherto healthy Aquatic plant life. It is highly advisable to gradually diversify the species of trees and to return the plants bark to their original state since, besides the naturalized plants, plantations afforested with Erigeron canadensis and Erigeron annuus stocks in buckwheat field, Robinia Pseudo-accacia in riverside forest, Pinus rigida in terrestrial forest on the river basin and Larix leptolepis are anticipated to act as interceptors of normal migrations of the fluvial and terrestrial ecosystems. Finally, it seems also desirable to continue to explore the relationship between fluvial and terrestrial ecologies with the purpose of building up a model of natural streams in urban areas based on the surveyed factors for plant life, soil and landscape and, moreover, on the forecasting for overall influences derived from the rotation upon the ecosystem.

A Study for the Calculation of Instream Flow in the Rehabilitation of Urban stream (도심하천 복원에 따른 하천유지유량 산정 연구)

  • Choi, Gye Woon;Chang, Yun Gyu;Han, Man Sin
    • Proceedings of the Korea Water Resources Association Conference
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    • 2004.05b
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    • pp.448-452
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    • 2004
  • Instream flow is necessary to manage the basic function of the rivers. The evaluation method of instream flow in a big river has been studied widely. However, the study in a urban hasn't researched. In theses days the environmental function of a river becomes very important. The evaluation method and secure of instream flow are basic conditions to perform it. Especially view of stream, recreation, protection of ecology are highly demanded In a urban according to the multipurpose of river spaces. In this paper the evaluation methods of instream flow were compared and investigated with many papers. This paper presents a proper evaluation procedure of instream flow in a urban stream through comparison and examination. According to the demanded hydraulic conditions the method can be considered the environmental function depend on the purpose of river restoration. The relationship of the coefficient of roughness and the slope of the river bed were examinated in order to estimate the minimum instream flow corresponding to proper Hydraulic conditions. Also calculate the instream flow of Sueng-gi stream in In-cheon.

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A Study on Improving the Unbalanced Deployment of Urban Parks (신·구시가지의 도시공원 불균형 분포 분석 및 개선방안 연구)

  • Sung, Hyun-Chan;Lee, Yang-Ju
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.15 no.3
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    • pp.1-15
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    • 2012
  • The objective of this study is to analyze the distribution of urban parks and its problems in a city in Gyeonggi-do where new towns and old towns are mixed. The study will also analyze and understand the unbalanced deployment of urban parks - rest areas and carbon absorbers of an entire city - between old towns and new towns, suggest improvement opportunities and examine and suggest plans to create and expand urban parks in old cities that lack urban parks. Findings showed that first, new towns were 1.2~1.6 higher than old towns in the number of parks, park area, and per capita park area, indicating that parks were unbalanced across towns. Second, as for a plan for improving the unbalanced deployment of urban parks, when the use area needs to be changed in an urban development project, it was suggested to donate 10% of the project site to the city to create it into a park and it was suggested to identify and proactively improve alternative park resources that can replace parks such as rivers and recreational sites. Third, regarding a plan for improving urban parks in old towns, it was suggested to secure urban parks by attracting various urban development projects to old town areas. The amendment of related laws was proposed to double required park area to $6m^2$ per household. Amendments were also suggested for one law and four guidelines to specifically define the location of urban parks as well.

Evaluation of Drain Pump System by Inundation Analysis in Urban Underground Passage (도시 지하차도 침수 분석을 통한 강제배제시설 평가)

  • Lee, Jung-Ho
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.8 no.5
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    • pp.1192-1200
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    • 2007
  • A general rainfall outflow in urban drainage has early time of concentration because urban drainage areas are most paved area. In general, rainfall outflow is flowed in drainage pump station and is discharged to rivers in urban areas. However it is excluded through drainage pumps about a heavy rainfall which exceed the design rainfall and the rainfall outflows increase the urban inundation risk. A current pump operation is control according to water level of collecting well or reservoir in drain pump station. But recently, the localized downpours are happened frequently in urban drainage and the current pump stations are frequently incapable of the heavy rainfall outflows. In this study, a real urban inundation was simulated and the drain capacity of drain pump station was evaluated by analysis about flood-factor in urban underground passage. Then the analysis about the inundation was done by the simulation about the real rainfall which cause the inundation. Also, in the simulation the inundation risk and the evaluation of flood-factor were analyzed according to change of the pump operation rule.

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Determination of Pollutant Unit Loads from Various Transportation Landuses (교통관련 포장지역 비점오염원에서의 오염물질 유출원단위 산정)

  • Lee, So-Young;Lee, Eunju;Maniquiz, Marla C.;Kim, Lee-Hyung
    • Journal of Korean Society on Water Environment
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    • v.24 no.5
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    • pp.543-549
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    • 2008
  • Human activities and land-use practices are intensely widening the urban areas. High impervious surface areas cover much of urban landscapes and are the primary pollutant sources which can lead to water quality and habitat degradation in its watershed. As the urban areas expand, transportation land-use such as parking lots, roads, service areas, toll-gates in highways and bridges also increase. These land-uses are significant in urban pollution due to high imperviousness rate and vehicular activities. To regulate the environmental impacts and to improve the water quality of rivers and lakes, the Ministry of Environment (MOE) in Korea developed the Total Pollution Load Management System (TPLMS) program. The main objective is to lead the watershed for a low impact development. On a local scale, some urban land surfaces can be emitting more pollution than others. Consequently, in urban areas, the unit loads are commonly employed to estimate total pollutant loadings emitted from various land-uses including residential, commercial, industrial, transportation, open lands such as parks and golf courses, and other developed land like parking areas as a result of development. In this research, unit pollutant loads derived specifically from transportation land-uses (i.e. branched out from urban areas) will be provided. Monitoring was conducted over 56 storm events at nine monitoring locations during three years. Results for the unit pollutant loads of transportation land-use are determined to be $399.5kg/km^2-day$ for TSS, $12.3kg/km^2-day$ for TN and $2.46kg/km^2-day$ for TP. The values are higher than those of urban areas in Korean MOE and US highways. These results can be used by MOE to separate the pollutant unit load of transportation landuses from urban areas.

An Assessment of Urban Water Cycle in Changwon-si Using GIS-based Water Cycle Area Ratio (GIS 기반의 물순환 면적률을 활용한 창원시 도심지역의 물순환성 평가)

  • Song, Bonggeun;Park, Kyunghun;Lee, Taeksoon
    • Journal of Environmental Impact Assessment
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    • v.22 no.5
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    • pp.397-408
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    • 2013
  • The purpose of this study is to analyze water cycle area ratio and spatial evaluation of water cycle in urban area of Changwon-si, Gyeongsangnam-do. Water cycle area ratio are analyzed by using spatial data of land-cover and land-use, and Hot spot analysis of GIS program was used for spatial evaluation of water cycle. The results are as below. Firstly, the high water cycle area ratio areas were forests, parks, and rivers, but urban areas covered asphalt and concrete were low under 40%. Public institutions and co-residential of urban areas were higher than others because of high area ratio of pervious land-cover. Spatial evaluation of water cycle was analyzed to vulnerable areas there are dense residential and commercial area. These areas are really occurring frequently flooding and immersion, therefore, is required water management facilities and improvement of land-cover from impervious to pervious. In the future, it will require additionally analysis of water cycle area ratio supplemented data of water management facility and ground water.

Characterization of Combined Sewer Overflows from a Small Urban Watershed and Determination of Optimum Detention Volume (소규모 도시유역 합류식 하수관거 월류수 특성화 및 최적 저류지 용량 결정)

  • Jo, Deokjun;Kim, Geonha
    • Journal of Korean Society on Water Environment
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    • v.22 no.2
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    • pp.314-320
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    • 2006
  • Diffuse pollution from an urban area contributes to the significant pollution loading to a receiving water body. In this paper, rainfall runoffs from an urban basin with combined sewer systems located in the city of Daejeon were monitored to measure the rainfall runoff discharge rates and pollutant concentrations. Strong first flush effects were observed for all monitored rainfall runoffs. The first flush effects were closely related to rainfall intensity, while suspended solids were closely related to pollutant constituents. The observed averaged Event Mean Concentrations (EMCs) of Combined Sewer Overflows (CSOs) were 536.1 mg SS/L, 467.7 mg CODcr/L, 142.7 mg BOD/L, 16.5 mg TN/L, and 13.5 mg TP/L. Storage volumes for containing the first flush to improve water quality of the receiving stream can be estimated based on suspended solid concentration. In this study, retainment of the first flush equivalent to 5mm of precipitation could reduce diffuse pollution loading induced by CSOs to a receiving water body by up to 80% of suspended solid loading.

A Study of Waterfront Use in Urban Rivers (도시하천의 수변공간 이용에 대한 연구)

  • Kim, Byeong-Chan;Kim, Man-Sik;Oh, Ji-Eun
    • Proceedings of the Korea Contents Association Conference
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    • 2011.05a
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    • pp.467-468
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    • 2011
  • 하천에서의 친수활동은 하천의 경관, 생태계, 물 등을 이용하여 이루어지는 인간활동과 심리적 만족감으로 하천어메니티의 한 요소로서 매우 중요하다. 그중 도시하천은 이용에 대한 요구와 자연환경보전이란 관심이 고조되고 있어 본 연구에서는 설문지 조사를 통한 전문가 의견을 토대로 다기준의사결정 기법을 이용하여 하천이용지수를 개발하였다.

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Analysis on the Use Characteristics of Citizen based on Urban Green Spaces Type - Focuses on Suwon-City - (도시녹지 유형에 따른 도시민의 이용 특성 연구 - 수원시를 대상으로 -)

  • Kim, Yea Sung;Kim, Hyun;Ko, Jinsoo
    • Journal of the Korean Institute of Landscape Architecture
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    • v.42 no.5
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    • pp.31-40
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    • 2014
  • The importance of green spaces in the city is growing each day. Local governments are taking charge of park development works that are having difficulty in developing and managing urban parks due to high land value as well as a shortage in finances. This is even though an urban park is defined as an urban planning facility and the law provides park area per person. Civil residents, meanwhile, are using not only urban parks provided by law but also other green areas such as rivers, reservoirs, and school playgrounds because they recognize urban green areas by the concept of use. In this study, accordingly, urban green areas were sorted into two types, urban parks, parks provided by law, and other green areas, and the difference in use pattern and use satisfaction by type was analyzed. As a result of analysis, there was no remarkable difference between the two types. According to such results, it was found that it is necessary to include other green areas, such as rivers, reservoirs, school green areas, and apartment green areas in addition to the current park green areas provided by law when park area per person is calculated, and such calculation of urban green areas reflecting local characteristics can reduce local governments' financial burden and improve the effectiveness of future urban park policies. It is judged that such results can become a plan against the cancellation of unexecuted urban facilities. The fact that accessibility factors, such as road satisfaction, access convenience, and convenient movement, are affecting satisfaction with the use of urban parks suggests that it is important to improve urban park accessibilities rather than to quantitatively expand park area in order to improve satisfaction with urban parks. Considering that people travel to urban green areas mostly by walking, it is necessary for access convenience to conduct follow-up studies such as barrier-free and securing walking stability through analysis of routes to urban green areas.

Urban Instream Flow Augmentation Using Reclaimed Water in Korea (하수처리수 재이용을 통한 도시하천 물순환 및 수질 개선)

  • Jee, Yong-Keun;Ahn, Jong-Ho;Lee, Jin-Hee
    • Journal of Korean Society of Water and Wastewater
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    • v.26 no.2
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    • pp.285-294
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    • 2012
  • Current urban stream conditions and their restoration projects were investigated by surveying the urban stream management experts in 29 cities with high population density (more than 1,000person/$km^{2}$). The survey results showed that the ratio of covered urban streams decreased by 1.4% (from 14% to 12.6%) in the last 5 years through steady river restoration projects promoted by governments. Nonetheless, 36.3% of 369 urban streams surveyed still report stream depletion problems; therefore, more efforts to alleviate the problems caused by distorted water circulation of urban streams are still necessary. Water depletion in many local urban streams, unlike national rivers, is accelerated due to negligence in stream management, budget shortage, and other reasons. To prevent stream depletion, the use of reclaimed water is suggested as one of the prevention plans. When available amounts of reused sewage are estimated through actual available nationwide sewage discharges of each watershed and instream flow of stream, annual instream flow supply of 780 million $m^{3}$ is expected; 4.8% reduction in the pollution load of public sewer treatment facilities is expected; and the creation of new value through water reuse service is expected. Thus, it is important for the reviews of feasibility and alternatives of water reuse projects for flow augmentation to consider not only investment budget reductions, but also environmental aspects. Also it is necessary to provide the financial support of unified government with strict water quality management policy.