• Title/Summary/Keyword: Impermeable area

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A Study on the Criteria for Demarcating Ecological Types of Urban Areas by the Affection of Ecosystems - Case Study in Gangdong-Gu, Seoul - (시가화지역 생태적 유형구분을 위한 관련지표 특성 연구 - 서울시 강동구를 사례로 -)

  • Hong, Suk-Hwan;Lee, Kyong-Jae
    • Journal of the Korean Institute of Landscape Architecture
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    • v.36 no.2
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    • pp.24-31
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    • 2008
  • Studies for demarcation of urban areas by ecological type have been developed, but the demarcation of urban areas by ecological perception is thus far dependent on artificial land use. Therefore, the purpose of this study is to find factors that account for the urban area ecosystems by surveying a variety of ecosystem factors. By land use type, the urban area of Gangdong District, Seoul was defined. Then ecological factors in each polygon were surveyed. Ecological factors are associated with energy use(building coverage ratio, floor area ratio and ground temperature), water circulation(biotope area factors and impermeable pave ratio) and biological diversity(bird appearance index and green area ratio). The correlation between each factor was analyzed. The results indicate that urban ground temperature is divided into three groups(high, middle and low) by the biotope area factor. The bird population is divided into two groups(abundant and scarce) by the green area ratio. Therefore, demarcating the urban areas by ecological type is applicable to the biotope area factor and green area ratio.

Washoff Characteristics and Correlation of Nonpoint pollutants in a Bridge Storm Runoff (교량 강우유출수내 비점오염물질의 유출특성 및 상관성)

  • Wee, Seung-Kyung;Kim, Lee-Hyung;Jung, Yong-Jun;Gil, Kyung-Ikt
    • Journal of Korean Society on Water Environment
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    • v.24 no.3
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    • pp.378-382
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    • 2008
  • During the dry periods, many types of pollutants are being accumulated on the paved surface by vehicle activities and the accumulated various pollutants are inflowing into the near watershed areas for the rainfall periods. Particularly, bridges are the centralized region to be the surface runoff of the stromwater due to the high ratio of the impermeable area. Also, the metals, toxic chemicals and sediments originated from bridges could be strongly influenced to the watershed areas during the runoff. Therefore, the present study is achieved to provide washoff characteristics and correlation from the bridge during rainfall periods. The result shows that the EMC ranges for 95% confidence intervals in a bridge land use are 10.12~128.09 mg/L for TSS, 6.07~21.15 mg/L for BOD, 2.10~6.70 mg/L for TN and 0.06~0.85 mg/L for TP.

A study on the Effective Operation of Pump Stations (빗물펌프장 운영합리화 방안 연구)

  • 한국원자력연구소
    • Journal of Korea Water Resources Association
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    • v.31 no.2
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    • pp.133-144
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    • 1998
  • Recent development booms in urban watersheds have increased impermeable areas and brought about an increase of peak flood. Eventually, some people living in the lower area of an urban watershed, very often and seriously, have suffered form inundation. In this study, for minimization of inundation in urban watersheds, the operational criteria for pump stations are suggested. At first, ILLUDAS has been selected as a runoff model which can explain the past precipitations. Secondly the operational criteria for pump stations could be suggested by working out an operational criteria for pump stations could be suggested by working out an operation program from the relationship between pumping capacity and accumulative hydrographs, and from the Intensity-Duration-Frequency relationship.

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열수변질 점토맥과 산사태

  • Jo, Hwan-Ju;Jeong, Gyeong-Mun;Jo, Ho-Yeong
    • Mineral and Industry
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    • v.29
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    • pp.56-66
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    • 2016
  • In Korea, where hydrothermal alteration zones are widely distributed, clay veins formed by hydrothermal alteration processes on natural slopes or artificial slopes can play an important role in the slope stability. When the surface water infiltrates the ground where the clay vein exists, the pore water pressure in the ground can be locally increased due to impermeable properties of clay minerals. Infiltration of the surface water induces the increase in the pore water pressure, which can cause erosion of the fine clay particles. The eroded clay particles flow and deposit in an area where the flow velocity is slowed down. Where clay minerals are deposited, ground water can leak due to an increase in local pore pressures, which can cause slope failure. In this paper, studies related to hydrothermal clay vein and landslide are introduced.

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Mapping and Analyzing the Park Cooling Intensity in Mitigation of Urban Heat Island Effect in Lahore, Pakistan

  • Hanif, Aysha;Nasar-u-Minallah, Muhammad;Zia, Sahar;Ashraf, Iqra
    • Korean Journal of Remote Sensing
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    • v.38 no.1
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    • pp.127-137
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    • 2022
  • Urban Heat Island (UHI) effect has been widely studied as a global concern of the 21st century. Heat generation from urban built-up structures and anthropogenic heat sources are the main factors to create UHIs. Unfortunately, both factors are expanding rapidly in Lahore and accelerating UHI effects. The effects of UHI are expanding with the expansion of impermeable surfaces towards urban green areas. Therefore, this study was arranged to analyze the role of urban cooling intensity in reducing urban heat island effects. For this purpose, 15 parks were selected to analyze their effects on the land surface temperature (LST) of Lahore. The study obtained two images of Landsat-8 based on seasons: the first of June-2018 for summer and the second of November-2018 for winter. The LST of the study area was calculated using the radiative transfer equation (RTE) method. The results show that the theme parks have the largest cooling effect while the linear parks have the lowest. The mean park LST and PCI of the samples are also positively correlated with the fractional vegetation cover (FVC) and normalized difference water index (NDWI). So, it is concluded that urban parks play a positive role in reducing and mitigating LST and UHI effects. Therefore, it is suggested that the increase of vegetation cover should be used to develop impervious surfaces and sustainable landscape planning.

Surface Image Analysis for Evaluating Porosity and Permeability Coefficient of Permeable Concrete Block (투수 콘크리트 블록 공극률 및 투수계수 평가를 위한 표면 이미지 분석 기법 개발)

  • Jo, Sangbeom;Son, Younghwan;Kim, Donggeun;Jeon, Jihun;Kim, Taejin
    • Journal of The Korean Society of Agricultural Engineers
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    • v.65 no.2
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    • pp.47-57
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    • 2023
  • The increase of impermeable area ratio is causing hydrologic cycle problems in urban areas and groundwater depletion in rural areas, permeable pavements are getting attention to expand permeable areas. The performance of the permeable concrete block pavement, which is part of the permeable pavement, is greatly affected by the porosity. In addition, the permeability coefficient is a major factor when designing permeable concrete block pavement. Existing porosity and permeability test methods have problems such as uneconomical or poor field applicability. The object of this study was to develop a methodology for evaluating porosity and permeability coefficient using a surface image of a permeable concrete block. Specimens are manufactured with various porosity ranges and porosity and permeability tests are performed. After surface image preprocessing, normalization and binarization methods were compared. Through this, the method with the highest correlation with the lab test result was determined. From the results, the PDR (pore determined ratio) was obtained. Simple linear regression analysis is performed with PDR and lab test results. The results showed a high correlation of R2 more than 0.8, and the errors were also low.

A Study on Non-point Source Pollutants from Pavement of Coastal Area and Guidance for Selecting BMP (연안지역 포장면 비점오염물질 유출 및 최적관리방안 시설의 선정을 위한 가이던스에 관한 연구)

  • Ko, Woong;Park, Kisoo;Chen, Yaoping;Kim, Youngchul
    • Journal of Wetlands Research
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    • v.15 no.4
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    • pp.543-553
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    • 2013
  • In Korea, there have been many studies and progresses on various types of pilot scale or commercialized field scale Best Management Practices(BMP) during the last 10 years. Runoff characteristics of diffuse pollutants from different land uses are well identified and documented. However, for the coastal area connected directly with shoreline, runoff patterns and management schemes of non-point pollution were not fully studied. Recently, coastal area is emerging as a new development axis especially in west coast side of Korea such as Incheon city and Chungnam province, thus urbanized area rapidly increased but there are no buffer zones and BMP facilities to aim at preventing direct discharge of the first flush into coastal sea and beaches. In this study, parking area in Deacheon harbor, Boryeong City in Chungnam Province was selected and rainfall runoff was monitored for two year period in order to examine run-off features from which proper type of BMP suitable for coastal area is proposed. Coastal area usually has a low ground water level and consists of plain land, so that large scale BMP such as storm water retention pond and wetland requiring great excavation works is not best management plan. In addition, monitoring study shows that storm water from the paved parking area has a high salinity compared with those in storm water from the inland. High salinity is detrimental for the vegetation. Therefore, BMP employing least vegetative cover and also in terms of maintenance is a good option such as infiltration trench and porous pavement.

Control of Short-period and Solitary Waves Using Two-rowed Impermeable Rectangular Submerged Dike (2열 불투과성 사각형 잠제를 이용한 단주기파랑 및 고립파의 제어)

  • Lee, Kwang-Ho;Jung, Sung-Ho;Ha, Sun-Wook;Kim, Do-Sam
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.22 no.4
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    • pp.203-214
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    • 2010
  • This study numerically investigates the wave control of 2-rowed Impermeable Rectangular Submerged Dike(IRSD) with an object of how to control short-period and solitary waves simultaneously based on the Bragg resonance phenomenon that elevates the wave control performance. The boundary integral method using Green formula and the 3-D one-field Model for immiscible TWO-Phase flows (TWOPM-3D) by 3-D numerical wave flume have been used for the numerical predictions for short-period and solitary waves, respectively. These numerical models were verified through the comparisons with the previously published numerical results by other researchers. Through the parametric tests of numerical experiments for short-period waves, an optimum model of 2-rowed IRSD of a lowest transmission coefficient has been found. Furthermore, the performances of 3-D wave control for solitary waves were evaluated for the various free board, crown widths and gap distance between dikes, and have been compared with those of a single-rowed IRSD. Numerical results show that a 2-rowed IRSD with a less cross sectional area than 1-rowed one improves the wave attenuation performances when it is compared to that of single-rowed IRSD. Within the test frequency ranges of the numerical simulations conducted in this study, 2-rowed IRSD with an optimum gap distance shows an outstanding improvement of the wave attenuation up to 58% compared to that of single-rowed IRSD.

Ecological Landscape Characteristics in Urban Biotopes - The Case of Metropolitan Daegu - (도시 비오톱의 경관생태학적 특성분석 - 대구광역시를 사례로 -)

  • 나정화;이정민
    • Journal of the Korean Institute of Landscape Architecture
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    • v.30 no.6
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    • pp.128-140
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    • 2003
  • The purpose of this research was to present characteristics for the classification of biotopes and classification method of biotopes as basic data for ecological landscape planning in Metropolitan Daegu. The results of this study were as follows. 1) The study identified fifteen characteristics for classification of biotopes. Ecological landscape characteristics were divided into structural and functional factors. There are six structural factors such an inclination, and nine functional factors such as temperature. 2) The study area was separated into sixty eight biotope types. For example, an industrial district was divided into two biotope types: a biotope type of an industrial district with abundant green space, and a biotope type of an industrial district with scarce green space. 3) In the result of cluster analysis using the average linkage method between groups, biotope groups were divided into fifteen clusters and biotope groups were divided into seven clusters. Each cluster was named according to the features of a descriptive statistics analysis. For example, cluster 8 was identified as a biotope type with an impermeable pavement rate of more than 90 percent and an afforestation rate under 10 percent. 4) Fifteen biotope groups were converted to land use patterns for remote application and utilization of urban biotope in city planning. Biotope groups of a building area beyond an intermediate floor with an afforestation rate under 20-30 percent was converted to a land use pattern such as a tall apartment complex or commercial district. When examining the characteristics that were established in this research, there was a limit to achieve the objective of grade-classification because of a lack of related basic data. The research of landscape ecological characteristics for the classification of biotopes could not be completed due to a lack of time and resources, thus the study of ecological landscape characteristics will be accomplished over time.

Analysis of Non-Point Source Pollution Reduction using Water Sensitive Urban Design in Gimhae, South Korea (김해시 물 순환 개선 도시계획에 의한 비점오염물질 저감효과 분석)

  • Jung, Kang-Young;Kim, Shin;Kwon, Hun-Gak;Yang, Duk Seok;Kim, Kyosik;Jang, Kwang-Jin;Shin, Dong-Seok;Ahn, Jung-Min
    • Journal of Environmental Science International
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    • v.25 no.11
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    • pp.1499-1509
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    • 2016
  • This study was performed to analyze the effects of a water circulation green area plan on non-point source pollution in Gimhae South Korea. A quantitative analysis of Arc-GIS data was conducted by applying a watershed model based on Fortran to investigate the changes to direct runoff and pollution load. Results showed that prior to the implementation of the water circulation green area plan in Gimhae, direct runoff was $444.05m^3/year$, total biological oxygen demand (BOD) pollution load was 21,696 kg/year, and total phosphorus (TP) pollution load was 1,743 kg/year. Implementation of the development plan was found to reduce direct runoff by 2.27%, BOD pollution load by 1.16% and TP pollution load by 0.19% annually. The reduction in direct runoff and non-point source pollution were attributed to improvements in the design of impermeable layers within the city.