• Title/Summary/Keyword: Urban rivers

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An Application of Infiltration Facilities for Reducing the Runoff in the Basin (유출저감을 위한 유역내 침투시설의 적용)

  • Lee, Jae-Joon;Seol, Ji-Su
    • Journal of the Korean Society of Hazard Mitigation
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    • v.11 no.3
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    • pp.133-141
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    • 2011
  • Urban development of basin causes increasing runoff volume and peak flowrate and shortening in time of concentration, which may cause frequent flooding downstream. An infiltration facilities are operated as a method of reducing flood discharge of urban rivers and peak flowrate. There are various types of infiltration facilities like infiltration trench and porous pavement. In this study, runoff reduction effect due to installation of infiltration facilities are performed and focused on $0.18km^2$ residential area of Ok-kye dong and $0.67km^2$ industrial area of Gong-dan dong in Gumi City. The analysis is fulfilled with comparison of total runoff volume and runoff reduction volume by using the WinSLAMM and the relation equation between area ratio of infiltration facilities and ratio of runoff reduction are derived and peak flow reduction effect for installation of infiltration facilities is analyzed.

Analysis of Physical Characteristics Affecting the Usage of Public Bike in Seoul, Korea - Focused on the Different Influences of Factors by Distance to Bike Station- (서울시 공공자전거 이용에 영향을 미치는 물리적 환경 요인 분석 -대여소별 거리에 따른 요인의 영향력 차이를 중심으로-)

  • Sa, Kyungeun;Lee, Sugie
    • Journal of Korea Planning Association
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    • v.53 no.6
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    • pp.39-59
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    • 2018
  • This study examines the relationship between the usage of public bike and physical environment factors around the public bike stations using the public bike rental history data from 2016 to 2017 in Seoul, Korea. Focusing on the different influences of determinant factors by distance to public bike station, this study identifies influential factors that affect the usage of public bike. The results of the analysis are as follows. First, both the land use and physical environmental variables of bike station areas show strong associations with the usage of public bike. Second, the usage of public bike is also associated with neighborhood living facilities, business facilities, land use mix, the distance to subway station, public facilities and universities. This finding indicates that public bike has played a role as a transportation mode for the short-distance travel and commuting purposes in everyday life. Third, this study shows that the usage of public bike is strongly associated with the average slope, traffic volume around public bike stations, distance to streams or rivers, and the types of bike lane. This finding also indicates that surrounding environmental factors play an important role in the usage of public bike. Finally, this study identifies the different influences of determinant factors on the usage of public bike by distance to public bike station. This study suggests policy implications for the potential locations of public bike stations in the future.

Study on the Removal Characteristics of Diazinon Using Ozone / Hydrogen Peroxide (오존/과산화수소공정(Peroxone AOP)을 이용한 Diazinon 제거 특성 연구)

  • Youn, Hyojin;Han, Ihnsup;Yoon, Woohyun
    • Journal of the Korean Society of Urban Environment
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    • v.18 no.4
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    • pp.391-399
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    • 2018
  • In this study, Diazinon which is the most widely used organophosphorus pesticides (OPPs) among pesticides was removed by ozone/hydrogen peroxide advanced oxidation process (Peroxone AOP). Diazinon is mainly found in groundwater, drinking water, rivers and ponds that are near agricultural areas using the pesticide. Accumulation of Diazinon on the body in the form of metabolites causes neurotoxicity, confusion, dizziness and vomiting. Diazinon is not easily removed by conventional water treatment processes. This study investigated the Diazinon removal characteristics with OH radicals with strong oxidizing power generated by using ozone and hydrogen peroxide. We determined optimal hydrogen peroxide/ozone injection molar ratio and confirmed the elimination reaction to initial Diazinon concentration, pH and DOC concentration, which are factors influencing the removal efficiency. Domestic researches on pesticide removal in the environment are much less than the cases of overseas. This study is expected to provide a basis for the process design for pesticide removal.

Comparison of inundation patterns of urban inundation model and flood tracking model based on inundation traces (침수 흔적도 기반으로 도시침수 모형과 홍수추적모형의 침수양상 비교)

  • Choi, Jonghwa;Jeon, Jaehyun;Kim, Taehyung;Kim, Byungsik
    • Journal of Korea Water Resources Association
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    • v.54 no.2
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    • pp.71-80
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    • 2021
  • In recent years, the possibility of flooding due to the increase in the incidence of high-frequency rainfall due to abnormal rainfall and the increase in concentrated torrential rain is increasing. Also, the amount of rainwater runoff is increasing due to the increase of the impermeable layer in the city due to the concentration of population due to urbanization and concentration of development. Due to the characteristics of the developed city, it is located in the vicinity of rivers and in the lowlands. For the analysis of inundation in water, using XP-SWMM, which can analyze stormwater pipelines and surface flows, and FLO-2D models that can track flood-sluice curves and rainfall-spill curves, based on hydraulic and hydrological analysis. Inundation analysis was conducted and comparative review was conducted. The patterns of flooding of the two models were compared, and a model suitable for domestic flooding was selected.

A Study on LIT Girder Performance Improvement (LIT 거더 성능 개선에 대한 연구)

  • Kim, Sung;Park, Sungjin
    • Journal of Urban Science
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    • v.11 no.2
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    • pp.19-24
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    • 2022
  • Conventional RC beams for crossing small and medium-sized rivers do not have a cross-sectional area, so the floating debris is accumulated and disasters such as damage to bridges occur. To improve this, the PSC method was invented. However, this also had problems such as transverse curvature, increase in dead weight due to cross-sectional shape, and negative moment generated during serialization, so it was necessary to develop a new type of girder. Therefore, it was intended to propose a LIT(Leton Interaction Thrust) girder bridge that is safer and has better performance than the conventional PSC girder with improved section efficiency. Unlike existing girder bridges, the LIT girder has the feature that the change in the strands of the entire girder occurs only in the vertical direction when the first tension is applied because the tendon arrangement is symmetrical by applying the raised portion. In addition, slab continuation generates a secondary moment that is advantageous to the continuous point, effectively controlling the negative moment and preventing the corrosion of the tendon. The dimensions of the cross section were determined, and the arrangement of the strands was designed to conduct structural analysis and detailed analysis. As a result of the structural analysis, the stress of the girder showed results within the allowable compressive stress, and the deflection showed the result within the allowable deflection. showed results. In addition, a detailed analysis was performed to examine the stress distribution around the girder body and the anchorage area and the stress distribution of the embossed portion, and as a result, the stress of the girder body due to the tension force showed a stable level.

Comparison and Application Quantitative Indices for Analyzing Total Green Space in an Urban Area - Guro-gu in Seoul - (도시 공원녹지의 총량 산정을 위한 지표 비교 및 적용 - 서울시 구로구를 사례로 -)

  • Lee, Kyong-Jae;Choi, Jin-Woo;Han, Bong-Ho
    • Journal of the Korean Institute of Landscape Architecture
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    • v.36 no.4
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    • pp.27-35
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    • 2008
  • The purpose of this study was to compare and apply quantitative indices for analyzing the total green space in an urban area, targeting Guro-Gu, Seoul. The indices were classified in terms of plane, solid and urban planning. The park area per person as an index of the park green's total volume was $2.34m^2$. This clearly shows the deficiency of park area. However, it did not reflect actual green space, since undesignated forests, rivers and green spaces in the city were excluded. Green coverage area per person in terms of plane was $18.85m^2$ and was useful as an index of actual urban planting, focusing on expansion of the green space. However, the conception of total volume of park green had limitation to be recognized as a unit of area. The number of trees and green area volume per person in terms of solid was 4.1 trees and $35.8m^2$, respectively. This enabled reflection on qualitative improvement plans such as increasing the volume of trees for the high density of developed areas.

Interaction between Groundwater and Surface Water in Urban Area (도시지역의 지하수와 하천수의 교류량)

  • Bae, Sang-Keun;Lee, Seung-Hyun
    • Journal of Korea Water Resources Association
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    • v.41 no.9
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    • pp.919-927
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    • 2008
  • Flow exchanges between stream and groundwater are assessed on urban streams in Daegu, Korea. Two rivers and 25 streams with the total length of 240 km run through the study area. The interaction between surface water and groundwater was estimated using Darcy's method. The study was conducted by dividing the basin into 16 smaller watersheds, and for comparison purposes. Groundwater level, surface water level, hydraulic conductivity, thickness of aquifer, and the distance between the well and the nearest stream were used for quantifying the interaction. To investigations the groundwater interaction in the watersheds, the amount of effluent seepage from groundwater to the stream, the amount of influent seepage from the stream to groundwater, and the amount of annual interaction between surface water and groundwater were computed. The total amount of effluent seepage from the groundwater to stream in the basin was approximately $72{\times}10^6m^3/year$. The total amount of influent seepage from the stream to groundwater was approximately $35{\times}10^6m^3/year$. It appeared that the total amount of annual interaction between surface water and groundwater was approximately $108{\times}10^6m^3/year$ and the total groundwater flow balance was approximately $37{\times}10^6m^3/year$. The annual amount of interaction between the surface water and groundwater was the largest in the Goryung Bridge Basin($29{\times}10^6m^3/year$) and the least in the Dalchang Dam Basin($0.2{\times}10^6m^3/year$). The results show that flow exchanges between stream and groundwater are very active and that there are significant difference among the smaller watersheds. Finally, the results indicate that it is necessary to further investigate to more precisely understand the interaction characteristics between surface water and groundwater in urban areas.

Heavy Metal Pollution in Sub-Saharan Africa and Possible Implications in Cancer Epidemiology

  • Fasinu, Pius Sedowhe;Orisakwe, Orish Ebere
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.6
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    • pp.3393-3402
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    • 2013
  • The increasing scourge of cancer epidemiology is a global concern. With WHO emphasizing that 40% of all cancer cases are preventable, exposure to known and suspected carcinogens must be discouraged. The battle with communicable diseases and other third world challenges has greatly de-emphasized anti-cancer campaigns in sub-Saharan Africa. The abundant deposit of mineral resources in sub-Saharan Africa has attracted high mining activity with its negative environmental aftermath. Poor regulatory mechanisms have led to environmental contamination by products of mining including heavy metals. In addition to poor urban planning, the springing up of settlements in industrial areas has led to generation and exposure to more hazardous wastes consequent on poor disposal systems. Studies establishing close association between exposure to heavy metals and cancer epidemiology in sub-Saharan Africa are increasing. The current review assesses the level of environmental pollution by heavy metals in sub-Saharan Africa, and brings to the fore available evidence implicating such in the increasing cancer epidemiology in the sub-continent.

Multi-Dimensional Hybrid Design and Construction of Skyscraper Cluster -Innovative Engineering of Raffles City Chongqing-

  • Wang, Aaron J.
    • International Journal of High-Rise Buildings
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    • v.6 no.3
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    • pp.261-269
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    • 2017
  • Designed by star architect of Moshes Safdie, Raffles City Chongqing includes a total of 6 mega high-rise towers 250 to 380 m tall, a sky conservatory, a 5-storey high shopping mall and a 3-storey basement car parking. Located at the confluence of the Yangtze and Jailing Rivers, the site for the project is imbued with a significance that is immediately symbolic, both as a sign of Chongqing's important past and as a vivid indicator of the city's thriving present and future. The design for the project to be situated at this gateway takes as its governing idea the image of powerful sails upon the water. The outer facades of the project's eight towers - the transparent surfaces that will face the water to the north - are meant to recall a fleet of ancient Chinese ships, with their huge rectangles of white canvas filled by the wind. This is a $1.13million\;m^2$ mega scale integrated project of office, retail, hotel, service residence and high-end residence with the transportation hub and traffic circulation at various levels of the project. This paper presents the multi-dimensional hybrid design, engineering and construction of this mega scale project. The innovations and the cutting-edge technology used in this project are introduced and discussed benchmarking the design and construction of the skyscraper cluster in a major city like Chongqing of China.

An Analytical Study of Foreign Researches and Examples on Ecological Restoration for the Small Stream (샛강 생태복원을 위한 해외 사례 연구의 고찰)

  • Kwon, Tae-Ho;Park, Jae-Hyeon;Kim, Dong-Wook
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.7 no.5
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    • pp.26-37
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    • 2004
  • Most domestic small rivers and streams due to industrialization and urbanization have managed by concrete structures. The environmental functions of the river and stream are disappearing and urban streams play only the role of drainage systems. Also, the researches to restore natural streams are something yet to develop and not established the restoration for ecological functions of a small stream. Therefore the researches are required to develop ecological engineering system for watershed management system to handle various pollutants with restoration for ecological functions of a small stream. To develop this, the ecological engineering system for watershed management system could be developed with ecological conservation. In addition, ecological engineering system for watershed management system should be prior to conserve the habitat of biological resources and water conservation and applied to the original shape of streams. Also, it should be designed to restore the micro-topography of stream, the habitat of plant population in watershed. It is needed to develop the integrated researches to restore a small stream ecosystem.