• Advances in environmental research
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• v.2 no.4
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• pp.279-290
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• 2013

In this study, a comprehensive model developed to estimate greenhouse gas (GHG) emissions from urban area with low impact development (LID) and its integrated management practices (IMPs). The model was applied to the actual urban area in Asan Tangjeong district (ATD) as a case study. A rainwater tank (1200 ton) among various LID IMPs generated the highest amount of GHG emissions ($3.77{\times}10^5kgCO_2eq$) and led to the utmost reducing effect ($1.49{\times}10^3kgCO_2eq/year$). In the urban area with LID IMPs, annually $1.95{\times}104kgCO_2eq$ of avoided GHG emissions were generated by a reducing effect (e.g., tap water substitution and vegetation $CO_2$ absorption) for a payback period of 162 years. A sensitivity analysis was carried out to quantitatively evaluate the significance of the factors on the overall GHG emissions in ATD, and suggested to plant alternative vegetation on LID IMPs.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.24 no.6
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• pp.109-119
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• 2021

Thermal environment of city is getting worse due to severe urban heat island caused by climate change and urbanization. Green roof improves the urban thermal environment and save the cooling energy in buildings. This study presented a green roof combined with a storage system that stores rain-water and supplies water through a wick and evaluated the temperature reduction effect as surface temperature and amount of evapotranspiration. For about a week, the surface temperature using a infrared thermal imager and the evapotranspiration by recording change of module weight were measured at intervals of 30 minutes from sunrise to sunset. The results show that the mean surface temperature of the green roof was 15.4 degrees lower than that of the non-green roof from 12:00 P.M. to 14:00 P.M. There was no significant difference between mean surface temperature of green roof with and without storage system immediately after rain, but more than a week after rain, there was a difference with average of 2.49 degrees and maximum of 4.72 degrees. The difference in daily amount of evapotranspiration was measured to be 1.66 times on average. As drought stress increased over time, the difference in daily amount of evapotranspiration and surface temperature between with/without storage system increased simultaneously. The results of the study show a more excellent cooling effect of green roof combined with the rainwater storage system.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.6
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• pp.719-726
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• 2009

One of the alternative runoff management measures is on-site runoff mitigation, such as rainwater retention tank and infiltration facilities especially the latter that is possible to manage simultaneously runoff quality and quantity as a perspective of water-cycle. This study was conducted to develop a particle separator, inclined-pipe settling system, that could improve particle removal efficiency of road runoff as a pre-treatment device of stormwater infiltration. Solid particles larger than $100{\mu}m$ are separated by simple sedimentation; however, the significant amount of pollutants with a diameter less than $100{\mu}m$ remain in suspension. Without any treatment in that case of the runoff into infiltrate, groundwater would be deteriorated and also infiltration rate would be decreased by clogging. Therefore, we suggest optimal design parameters (inclined angle, pipe length, and surface loading rate) of inclined-pipe settling system which can be designed to effectively remove particles diameter smaller then $70{\mu}m$. Thus, the results showed TSS removal efficiency more than 80% with a particle diameter between $20{\mu}m$ and $70{\mu}m$, 100% above particle diameter $70{\mu}m$ for the inflow rate $0.018 m^3/m^2{\cdot}hr$ with pipe inclined at angle $15^{\circ}$.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.1
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• pp.92-99
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• 2009

Deeply-driven ground rod in the rainy season may contact with rainwater and ground water. When surge voltages are applied to the submerged ground rods, the ionization around the ground rods are occurred. Ionization in soil and/or water is affected in dynamic performance of ground rod systems. This work aims at studying the transient performance of ground rod system under impulse voltage using scale model in an electrolytic tank. The potential reduction and energy dispersion caused by ionization were treasured and quantitatively analyzed using the Matlab Program. As a result, the peak voltage at the terminal of ground rod was varied with water resistivity and charging voltage of Marx generator. The potential at the terminal of the ground rod was approximately reduced to a half of the applied voltage just below breakdown voltage. Also the energy more than half of the applied energy was dispersed through the ground rod due to ionization just below breakdown voltage.

• Journal of Environmental Science International
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• v.22 no.5
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• pp.639-649
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• 2013

Over 96.2% of the agricultural water in Jeju Island is obtained from groundwater and there are quite distinct characteristics of agricultural water demand/supply spatially because of regional and seasonal differences in cropping system and rainfall amount. Land use for cultivating crops is expected to decrease 7.4% (4,215 ha) in 2020 compared to 2010, while market garden including various vegetable crop types having high water demand is increasing over the Island, especially western area having lower rainfall amount compared to southern area. On the other hand, land use for fruit including citrus and mandarin having low water demand is widely distributed over southern and northern part having higher rainfall amount. The agricultural water demand of $1,214{\times}10^3\;m^3/day$ in 2020 is estimated about 1.39 times compared to groundwater supply capacity of $874{\times}10^3\;m^3/day$ in 2010 with 42.4% of eastern, 103.1% of western, 61.9% of southern, and 77.0% of northern region. Moreover, net secured amount of agricultural groundwater would be expected to be much smaller due to regional disparity of water demand/supply, the lack of linkage system between the agricultural water supply facilities, and high percentage of private wells. Therefore, it is necessary to ensure the total net secured amount of agricultural groundwater to overcome the expected regional discrepancy of water demand and supply by establishing policy alternative of regional water supply plan over the Island, including linkage system between wells, water tank enlargement, private wells maintenance and public wells development, and continuous enlargement of rainwater utilization facilities.

• Journal of the Korean association of regional geographers
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• v.19 no.4
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• pp.615-626
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• 2013

In this study, spatial patterns of the urban flood vulnerability index in Seoul are examined by considering climate exposure, sensitivity, and adaptability associated with floodings for recent 5 year (2006~2010) period by the smallest administrative unit called Dong. According to the results of correlation analyses based on the IPCC(Intergovernmental Panel on Climate Change)'s vulnerability model, among many variables associated with urban flooding, rainwater tank capacity, 1-day maximum precipitation and flood pumping station capacity have statistically-significant, and relatively-high correlations with the number of flood damage in Seoul. The flood vulnerability map demonstrates that the extensive areas along Anyang and Joongnang streams show relatively high flood vulnerability in Seoul due to high sensitivity. Especially in case of Joongnang stream areas, climatic factors also contribute to the increase of flood vulnerability. At local scales, several Dong areas in Gangdong-gu and Songpa-gu also show high flood vulnerability due to low adaptability, while those in Gangnam-gu do due to high sensibility and climate factor such as extreme rainfall events. These results derived from the flood vulnerability map by Dong unit can be utilized as primary data in establishing the adaptation, management and proactive policies for flooding prevention within the urban areas in more detail.