• Journal of Korean Society of Water and Wastewater
• /
• v.35 no.2
• /
• pp.163-174
• /
• 2021

Heatwaves are one of the most common phenomena originating from changes in the urban thermal environment. They are caused mainly by the evapotranspiration decrease of surface impermeable areas from increases in temperature and reflected heat, leading to a dry urban environment that can deteriorate aspects of everyday life. This study aimed to calculate daily maximum ground surface temperature affecting heatwaves, to quantify the effects of urban thermal environment control through water cycle restoration while validating its feasibility. The maximum surface temperature regression equation according to the impermeable area ratios of urban land cover types was derived. The estimated values from daily maximum ground surface temperature regression equation were compared with actual measured values to validate the calculation method's feasibility. The land cover classification and derivation of specific parameters were conducted by classifying land cover into buildings, roads, rivers, and lands. Detailed parameters were classified by the river area ratio, land impermeable area ratio, and green area ratio of each land-cover type, with the exception of the rivers, to derive the maximum surface temperature regression equation of each land cover type. The regression equation feasibility assessment showed that the estimated maximum surface temperature values were within the level of significance. The maximum surface temperature decreased by 0.0450℃ when the green area ratio increased by 1% and increased by 0.0321℃ when the impermeable area ratio increased by 1%. It was determined that the surface reduction effect through increases in the green area ratio was 29% higher than the increasing effect of surface temperature due to the impermeable land ratio.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.11 no.2
• /
• pp.193-198
• /
• 2011

This study aimed to provide basic data for permeable pavement application upon design and installation stages by analyzing the effect of permeable pavement used on the facility area rather than using non-point pollutants treatment facility upon development business in accordance with recent trend. To perform this study, the area of development target was separately applied as impermeable and permeable developments so as to compare and analyze the economics of cut pollution load and installation construction cost. Consequently, the processing amount and cut load of non-point pollutant sources are influenced much by permeable and impermeable developments, and it was turned out to be better to develop target river area as permeable area rather than installing non-point pollutants treatment facility of equipment type or natural type upon development to yield smaller discharge load. If we can prepare a countermeasure regulating impermeable area ratio to certain level to manage non-point pollutants upon development based on this result, we can minimize the source of pollution caused by the development.

• Korean Journal of Environment and Ecology
• /
• v.18 no.1
• /
• pp.53-60
• /
• 2004

This study was carried out to investigate the effect of green area in apartment complexes to variation of temperature. The inside temperature of each site was estimated by analyzing Landsat ETM＋ image data. The factors on variation of temperature were landcover type, building density, and Normalised Difference Vegetation Index(NDVI). The results of correlation between inside temperature of apartment complex and land cover type showed that the green area ratio had negative(－) correlation and impermeable pavement ratio had positive(＋) correlation. Building-to-land ratio was not significant with inside temperature. A coefficient of correlation between the temperature value and the value of permeable pavement ratio added up green area ratio was higher than a coefficient of correlation between the temperature value and the value of permeable pavement ratio added up impermeable pavement ratio. Thus we may define that permeable pavement area decrease urban temperature with green area in apartment complex. Floor area ratio had no significant correlation with inside temperature. Inside temperature was decreased as the NDVI was increased. To establish the temperature distribution model in a development apartment complex, As the result of regression analysis between inside temperature as dependent variable and permeable pave ratio+green area ratio, green area ratio, building-to-land ratio and NDIT as independent variables, only permeable pavement ratio added up green area ratio of the independent variables was accepted fur regression equation in both two seasons and adjusted coefficient of determination was 41.4 on September, 2000 and 40.4 on June,2001.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.23 no.3
• /
• pp.105-119
• /
• 2020

The purpose of this study is to analyze the hydrologic cycle environment of Gyeongui Line Forest Park, a linear city park, in order to improve hydrologic cycle systems in urban areas. The method of the study is the Biotope Area Ratio and the Permeable ratio survey. The study subject is the Gyeongui Line Forest Park, created in 2016 as a linear park in Seoul. The results showed that the Biotope Area Ratio improved by 31.2% (31,927㎡) from 35.7% (36,480㎡) in 2000 to 66.9% (68,407㎡) in 2019 on a site area of 102,117㎡. Next, the Permeable ratio improved by 43.8% from 29.0% to 72.8%, and the impermeable ratio decreased by 43.8% from 71.0% to 27.2%. The Biotope Area Ratio exceeded the target ratio of 60% by 6.9%, set by the Ministry of Environment. The ratio of green space exceeded the target ratio of 60%, by 4.0%. And so they contributed to the improvement of the hydrologic cycle by the creation of the Gyeongui Line Forest Park. Urban parks need to exceed the Biotope Area Ratio and the green area ratio of the legal standards, especially when creating large parks of over 100,000 square meters, in the era of climate change. It is necessary to continuously plant trees in the space where trees can be planted, and to contribute to the improvement of the hydrologic cycle system and urban heat island effect by conducting three-dimensional.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.23 no.6
• /
• pp.167-185
• /
• 2020

The purpose of this study is to prepare a plan for improving the bird habitat environment of Linear Park. To this end, after grasping the status of bird habitats on the Gyeongchun Line Forest Road, a representative linear park in Seoul, the habitat environment was evaluated and the correlation with the bird habitat was analyzed to derive a plan to improve the habitat environment. The results for correlation between diversity of birds and habitat environment were as follows. For the habitat environment inside the park, the order of positive correlation was in the order of park area (0.92), number of insect species (0.87), green area ratio (0.77), average width of linear park (0.74), Biotope area ratio (0.73), Immigration planted species (0.57). Also, for habitat environment outside the park, the bird diversity was influenced in the order of area outside the park (0.88), green area ratio of the park (0.76). Thus, in order to enhance the diversity of birds found in the park, the bird habitat environment inside the park needs to expand the park area, secure insect diversity, enhance green area ratio and ecological area ratio, expand the width of linear park, and lower the impermeable layer. For the bird habitat environment outside the park, wider area, green area ratio, and forest area of the park influenced on better bird habitation while lower ratio of road space and building-to-land ratio influenced on higher bird diversity. It is necessary to create an environment inhabitable for various species of birds and to make a healthy and pleasant city urban system for co-existence of human and living creatures.

• Korean Journal of Remote Sensing
• /
• v.20 no.5
• /
• pp.329-335
• /
• 2004

Biotop map can be utilized for nature conservation and assessment of environmental impact for human activities in urban area. High resolution satellite images such as IKONOS and KOMPSAT1-EOC were interpreted to classify land use, hydrology, impermeable pavement ratio and vegetation for biotop mapping. Wildlife habitat map and detailed vegetation map obtained from former study results were used as ground truth data. Vegetation was investigated directly for the area where the detailed vegetation map is not available. All these maps were combined and the boundaries were delineated to produce the biotop map. Within the boundary, the characteristics of each polygon were identified, and named. This study investigates the possibility of biotop mapping using high resolution satellite remote sensing data together with field data with the goal of contributing to nature conservation in urban area.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.36 no.2
• /
• pp.24-31
• /
• 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.

• Journal of Korea Water Resources Association
• /
• v.38 no.3 s.152
• /
• pp.213-222
• /
• 2005

This study is a sensitivity analysis of the parameters which affect the simulation results under various design rainfall conditions, using the SWMM model, for three selected basins in urban areas. The sensitivity of the peak flow rate is defined by $S_Q$ (=1.0 - (min. ratio of peak flow rate/max. ratio of peak flow rate)), and the rainfall conditions are classified in terms of design rainfall frequency, duration, and distribution. The simulation results show that in most conditions the parameters - the impermeable area ratio, the sewer slope, and the initial infiltration capacity - have more significant effects on the results than other parameters. As the design rainfall frequency increases, the sensitivity of the sewer slope and sewer roughness increases, while the parameters related with the surface runoff decrease. When the rainfall duration increases, the sensitivities of most parameters of surface runoff and sewer flow decrease. Also, at the 1st quarterly Huff rainfall distribution condition, the impermeable area ratio has high sensitivity, but at the 4th quarterly condition the parameters related with sewer flow show higher sensitivities. These tendencies can be explained by considering the procedure for computing the effective rainfall and kinematic wave on the surface and sewer flow.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.23 no.5
• /
• pp.1-14
• /
• 2020

In order to improve the urban thermal environment, efforts are being made to increase green areas in cities that include park construction, planting, and green roofing. Among these efforts, urban parks play an important role not only in improving the urban thermal environment, but also in terms of ecosystem services (serving as resting places for citizens, providing cleaner air quality, reducing noise, etc.). Therefore, the purpose of this study is to suggest planning and management guidelines for urban parks that are effective in improving the thermal environment, by analyzing the urban surface temperature reduction performance of urban parks. To do this, first, land surface temperature was calculated by using Landsat 8 images. Second, the PCI (Park Cool Island) index was calculated to identify the temperature reduction performance of urban parks. Third, the characteristics of parks (area, shape, vegetation) and the surrounding spatial characteristics (land cover, building-related variables, etc.) were identified. Finally, the relationship between the PCI indices (PCI scale, PCI effect, PCI intensity) and the characteristics of the parks and their surroundings were analyzed. The results revealed that the parks consisting of a larger area, simple shape, and higher tree coverage ratio had increased PCI performance, and were advantageous for improving the urban thermal environment. Meanwhile, PCI performance was found to have decreased in areas with a higher impermeable area ratio and building coverage ratio. The outcomes of this study can be used to identify priority areas for planning and management of urban parks and can also be utilized as planning and management guidelines for improving urban thermal environment.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.65 no.2
• /
• pp.47-57
• /
• 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.