• Journal of the Korean Society of Environmental Restoration Technology
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• v.25 no.6
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• pp.51-64
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• 2022

Along with the urbanization, the risk of urban flooding due to climate change is increasing. Flood regulation, one of the ecosystem services, is implemented in the different level of function of flood risk mitigation by the type of ecosystem such as forests, arable land, wetlands etc. Land use changes due to development pressures have become an important factor in increasing the vulnerability by flash flood. This study has conducted evaluating the urban flood regulation service using InVEST UFRM(Urban Flood Risk Model). As a result of the simulation, the potential water retention by ecosystem type in the event of a flash flood according to RCP 4.5(10 year frequency) scenario was 1,569,611 tons in urbanized/dried areas, 907,706 tons in agricultural areas, 1,496,105 tons in forested areas, 831,705 tons in grasslands, 1,021,742 tons in wetlands, and 206,709 tons in bare areas, the water bodies was estimated to be 38,087 tons. In the case of more severe 100-year rainfall, 1,808,376 tons in urbanized/dried areas, 1,172,505 tons in agricultural areas, 2,076,019 tons in forests, 1,021,742 tons in grasslands, 47,603 tons in wetlands, 238,363 tons in bare lands, and 52,985 tons in water bodies. The potential economic damage from flood runoff(100 years frequency) is 122,512,524 thousand won in residential areas, 512,382,410 thousand won in commercial areas, 50,414,646 thousand won in industrial areas, 2,927,508 thousand won in Infrastructure(road), 8,907 thousand won in agriculture, Total of assuming a runoff of 50 mm(100 year frequency) was estimated at 688,245,997 thousand won. In a conclusion. these results provided an overview of ecosystem functions and services in terms of flood control, and indirectly demonstrated the possibility of using the model as a tool for policy decision-making. Nevertheless, in future research, related issues such as application of models according to various spatial scales, verification of difference in result values due to differences in spatial resolution, improvement of CN(Curved Number) suitable for the research site conditions based on actual data, and development of flood damage factors suitable for domestic condition for the calculation of economic loss.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6D
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• pp.1019-1023
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• 2006

The slope information based on DEM is very useful for urban planning, landscape, road design and water resource areas such as rainfall-runoff and soil erosion estimation. The resolution of slope, which is from DEM, can be variously decided by an application fields and the kinds of modeling method. In particular, the more decreased resolution makes the more decreased slope value because of the increased horizontal distance. This study presents slope evaluation method by aggregation method based on discharge and Manning's velocity equation to advance the loss of slope information in according to the resolution, and then applied it to calculate topographic factors of soil erosion model. As a result, conventional method shows 34.8% errors but aggregation method shows 12.6% errors. This study selected up-, middle-, and downstream region in watershed and analyzed the capability of aggregation method in order to estimate the influence of topographic characteristics. As a result of estimation, aggregation method shows more advanced results than conventional method. Therefore, the slope evaluation method by aggregation method can improve efficiently the loss of slope information in according to the variation of resolution in water resource area such as rainfall-runoff model.

• Journal of Wetlands Research
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• v.19 no.3
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• pp.259-270
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• 2017

In this study, field-scale half-saturated bio-filter wetland equipped with recirculation system was operated with stormwater from the paved road, and its operational performance and functions of LID-BMP were analyzed and compared with other facilities. The reduction of TSS, COD, TN, and TP were 92%, 63%, 36%, and 75%, respectively. Comparison of the reduction efficiency were carried out with respect to ratio between surface and catchment areas(SA/CA). In addition, this LID-BMP facility can reduce about 70% of pollutant by treating only 18% of total rainfall runoff. The results show that LID used for this study gave similar efficiency although its ratio was smaller. In addition, comparison study was made between synthetic fiber as a filter media and organic media, which shows that there was not any significant difference between, TSS and TP reduction, but there were large difference in COD and TN removal due to the presence and absence of release of organic carbon. Meanwhile, wetland system in this study equipped with a first-flush capture gave a higher stability in terms of treatment performance.

• Journal of the Korean GEO-environmental Society
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• v.10 no.4
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• pp.33-40
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• 2009

In earthwork projects, the designer considers cut and fill balance for minimizing earthwork which may significantly decrease construction costs. Despite carrying out considerable earthwork design, the decrease in volume of earth occurs in construction sites because of embankment settlement under self-weight, consolidation settlement of soft ground, cavity filling and soil loss due to rainfall-runoff. To reflect the decrease in volume of earth, the specifications for road construction just give shrinkage factors in embankment for soils without consideration of embankment settlement under self-weight. In this study, the computational method is used to estimate the amount of embankment settlement under self-weight developed by Iseda (1972) and Ishii (1976). This research shows that the total compression settlements are between 3 to 10 percent of embankment height according to the property of embankment material and embankment height. As a result, the designer should consider the compression settlement on embankment material under selt-weight.

• Journal of Korean Society of Transportation
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• v.24 no.7 s.93
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• pp.7-14
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• 2006

Most researches about rumble strips have Presented only the before-and-after analysis of the accidents. So, Researchers have not dealt with the estimation of rumble strip's effectiveness on the driver's alertness. In this study. the effectiveness of the rumble strips on the driver's alertness was estimated by measuring the bio-signal transmitted from the driver. The bio-signal acquired for this experiments were theta wave in central lobe. The experimental results revealed that the theta waves as measured form the drivers's head while in the rumble strip section differed from those while in non-rumbled section; 74 percent decrease in theta wave value, respectively. This fact finding could mean that the driver's alertness increased from 74 percent while in the rumble strip section of the road. In all five trials of driving experiments on the rumble strip section, all the drivers showed the best alertness as measured by the theta waves in the first driving trial.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.94-96
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• 2003

Since 1995, MOCT(Ministry of Construction and Transportation) and KOWACO(Korea Water Resources Corporation) have established the National Groundwater Monitoring Network in South Korea and also MOE(Ministry of Environment) has operated Groundwater Quality Monitoring network. Until 2001, 202 monitoring stations by MOCT and 780 monitoring wells by MOE have been constructed, measured groundwater level and analyzed water samples. Groundwater quality analysis has been conducted two times a year during last 6 years for all monitoring wells. The quality data has about 15 components including pH, COD, Count of Coliform group, and etc.. Trend analysis has been peformed for 6 components(Coliform, pH, COD, NO$_3$-N, Cl and EC) of water quality which are analyzed more than 7 times for total monitoring wells. Two test methods have been used ; Sen's test and Mann-Kendall test. These trend tests have been done at the 0.05 significance level. By the result of Sen's test, Count of Coliform group has either upward or downward trends at 4.3 percent of the monitoring points. pH does at 5.6 percent, COD does at 8.6 percent, Nitrate-Nitrogen does at 13.2 percent, Chloride does at 13.4 percent, and. EC does at 11.6 percent of the monitoring points. The exact causes of the groundwater quality trends are difficult to specify. Notable downward trends in nitrate at many monitoring points may be the result of reduction on some contamination sources. Potential causes include diminished agricultural areas, improvements in sewage treatment and a decrease in atmospheric deposition. Increase in chloride at many monitoring points may be the result of increased non-point source pollution such as road salting and runoff from sprawling paved developments and suburbs.

• Journal of Environmental Impact Assessment
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• v.18 no.5
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• pp.281-291
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• 2009

In Total Water Pollutant Load Management System of Korea, unit load approach based on land register data is currently used for the estimation of non-point pollutant load. However, a problem raised that land register data could not always reflect the actual land surface coverages which determine runoff characteristics of non-point pollution sources. As a way to overcome this, we tried to establish quantitative relationships between the aerial images (0.4m resolution) which reflect actual land surface coverages and the land registration maps according to the 19 major designated land-use categories in Kyeongan watershed. Analyses showed different relationships according to the land-use categories. Only a few land-use categories including forestry, road and river showed essentially identical and some categories such as orchard, parking lot and sport utility site showed no relationships at all between image data and land register data. Except for the two cases, all the other categories showed statistically significant linear relationships between image data and land register data. The analyses indicate that using high resolution aerial maps is a better way to estimate non-point pollutant load. If the aerial maps are not available, application of the linear relationships as conversion factors of land register data to image data could be an possible option to estimate non-point pollutant loads for the specific land-use categories in Kyeongan watershed.

• Economic and Environmental Geology
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• v.32 no.6
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• pp.633-644
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• 1999

Gully pot is a part of urban darainage system to butter the runoff water fluxes from road to rivers and to minimize environmental pollution by prevending over the surrounding area. A series of studies have been carried out concerning the physicochemical characteristics of the sewage sludge sediments sttling down in such a gully pot in order to over to evaluate the contamination for heavy metals such as pb, Zn, Cu and Cd. The roadside soil and sewage sludge samples from gully pots were characterized by XRD analyses and sequential extraction : Zn 2595.7$\mu$g/g; Cd9.8$\mu$/g; Cu602.5$\mu$g/g; Pb260.0$\mu$g/g),because of a long-term accumulation of vehicle- and industrial-related pollutants. Mean Zn concentration in Yeouido (3873$\mu$g/g) and Junggu(3262$\mu$g/g)areas are 4-5 times higher than those in Dobonggu area, suggesting that Zn may be derived from automobile traffic (including the rubber of automobile tires). The mean concentrations of Cu and Cr are very significantly high in Junggu and Gurogu areas, possibly due to the industrial activities in these areas. The low Pb levels throughtotut the whole study areas in Seoul can be accounted for the use of unleaded gasoline since 1987. Sequential extraction experiments illustrate that a major part of Zn is bound to FII and FIII, representing about 88% of the total Zn concentration. Fraction IV, related to orgnic matter, is mostly significant for Cu accounting for 60% of the total Cu, and FII is next in importance. The main carriers of Pb are the fractions III, II and FIV, and in that order. The behavior of Cd is quite different from other elements (Zn, Cu, Pb), and most of the Cd is associated with FV. Changes in the physicochemical environments (such as acidification) may result in severe environmental pollution of surface water and rivers with respect to heavy metals (especially Zn and Cu).

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.232-232
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• 2023

고속도로 및 편의시설 건설로 불투수층의 면적이 증가하여 강우 시 고속도로 및 편의시설에서 발생하는 오염원에 의한 하천의 수질 영향도 커지고 있다. 특히 휴게소에서는 자동차의 급가속, 급감속으로 더욱 많은 분진과 오염물질이 발생할 수 있으며 타이어 마모 입자, 자동차 배기가스, 중금속 및 오일류 등이 휴게소나 도로 지표에 집적되어 있다. 이렇게 발생한 오염물질은 우기에 강우와 함께 불투수면을 침투하지 못하고 배수로를 통해 유출되어 인근 하천의 수생태 및 토양의 주요 오염원으로 작용하고 있다. 이에 따라 고속도로 및 인근 휴게소의 비점오염 저감대책이 필요하며 효율적인 비점오염원 저감을 위해 장기적인 모니터링, 지속적인 자료 수집 및 분석이 필요하다. 본 연구에서는 강원지역 고속도로 및 인근 휴게소에서 강우 시 강우유출수 모니터링을 통해 강우유출수 유량가중평균농도 (Event Mean Concentration) 산정하고 강우유출수 수문곡선 (hydrograph)을 작성하였다. 또한 강우사상에 따른 분석항목별 초기세척효과(First Flush Effects)와 오염부하량을 산정하였다. 추가적으로 차량 기인 입자를 확인하기 위해 μ-FT-IR 현미경 분석 실험을 하였다. 모니터링 장소는 휴게소 및 고속도로 일원이며, 모니터링은 선행무강우일수 2일 이상, 강우량 10mm 이상일 때 실시하였으며 2022년 6월부터 10월까지 총 4회 실시하였다. 모니터링 결과 타이어 및 브레이크 패드 마모와 관련된 중금속인 Zn, Cu, Pb 등의 중금속이 높게 분석되었으며 이러한 중금속의 오염부하량 역시 높게 산정되었다. 강우유출수 수문곡선에서 강우 초기 오염물질의 세척효과가 나타났다. MFFn 산정 결과 강우 30% 구간에서 초기세척효과를 보였다. μ-FT-IR 현미경 분석 결과 PE (Polyethylene)가 가장 많이 검출되었고 PP (Polypropylene), PS (Polystyrene) 순으로 검출되었다. 이러한 강우유출수 모니터링 데이터는 향후 고속도로 휴게소 및 고속도로 주변 오염저감 시설 설치 및 사회적 동참을 위한 타당한 근거 확보를 위한 기초자료로서 제공될 수 있을 것이다.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.11
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• pp.1007-1018
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• 2009

Hydrocyclone is widely used in industry, because of its simplicity in design, high capacity, low maintenance and operational cost. The separation action of a hydrocyclone treating particulate slurry is a consequence of the swirling flow that produces a centrifugal force on the fluid and suspended particles. In spite of hydrocyclone have many advantage, the application for treatment of urban stormwater case study were rare. We conducted a laboratory scale study on treatable potential of micro particles using hydrocyclone filter (HCF) that was a combined modified hydrocyclone with perlite filter cartridge. Since it was not easy to use actual storm water in the scaled-down hydraulic model investigations, it was necessary to reproduce ranges of particles sizes with synthetic materials. The synthesized storm runoff was made with water and addition of particles; ion exchange resin, road sediment, commercial area manhole sediment, and silica gel particles. Experimental studies have been carried out about the particle separation performance of HCF-open system and HCF-closed system. The principal structural differences of these HCFs are underflow zone structure and vortex finder. HCF was made of acryl resin with 120 mm of diameter hydrocyclone and 250 mm of diameter filter chamber and overall height of 800 mm. To determine the removal efficiency for various influent concentrations of suspended solids (SS) and chemical oxygen demand (COD), tests were performed with different operational conditions. The operated maximum of surface loading rate was about 700 $m^3/m^2$/day for HCF-open system, and 1,200 $m^3/m^2$/day for HCF-closed system. It was found that particle removal efficiency for the HCF-closed system is better than the HCF-open system under same surface loading rate. Results showed that SS removal efficiency with the HCF-closed system improved by about 8~20% compared with HCF-open system. The average removal efficiency difference for HCF-closed system between measurement and CFD particle tracking simulation was about 4%.