• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.285-285
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• 2021

급격한 기후변화의 영향으로 강수량은 증가하는 반면 강수일수는 점차 감소하며, 지속적인 도시화로 인해 불투수 면적이 증가하여 침투량은 감소하고 우수 유출량은 증가하고 있다. 이러한 우수 유출량의 증가로 인한 홍수피해에 대한 대책으로 분산형 유출저감 시설인 저영향개발(LID)이 해결방안으로 제시되고 있다. 기존연구에서는 대부분 LID 시설별 우수 유출 저감 효과를 분석하거나, LID 시설의 설치 비율과 강우빈도를 다양하게 적용하여 유출량과 침투량 등을 분석하였다. 그러나 기후변화로 인하여 미래 호우 패턴은 과거와는 다를 것으로 예상되므로 장기적인 측면에서 기후변화 시나리오에 따른 분석을 수행할 필요가 있다. 따라서 본 연구에서는 대표농도경로(RCP)에 따른 기후변화를 반영한 미래 호우사상에 대하여 LID 적용 면적 대비 최고의 효율을 나타낼 수 있는 LID 적용 비율을 산정하였다. 이를 위해 빈번하게 침수피해가 발생하는 동대문구에 위치한 용두빗물펌프장 유역을 선정하였으며, 다양한 LID 기법 중 설치가 용이한 투수성 포장과 옥상녹화, 그리고 도로와 단지에 적용성이 높고 저류기능과 여과기능 등이 있는 식생 체류지를 대상 LID 기법으로 선정하였다. 과거와 미래의 대표 호우사상에 대한 유출량을 SWMM으로 산정한 결과, 강수량은 110.5 mm에서 319.42 mm로 증가하였고, 지표 유출량은 87.346 mm에서 294.63 mm로 증가하였다. 그리고 LID 기법 중 세 가지를 모두 적용한 경우 지표면 유출량이 294.63 mm에서 100.3 mm로 가장 큰 폭으로 감소하였다. 또한 저감 효율이 가장 좋은 설치 면적 비율을 도출하기 위하여 다양한 LID 설치면적 비율에 대한 분석을 하였으며, 유역전체면적대비 적용면적비에 따른 우수유출 저감율을 저감효율로 정의한 결과, LID 설치비율이 60%인 경우가 지표 유출량은 1.37, 저류량은 0.50으로 가장 큰 효율이 나타났다.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.5
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• pp.59-64
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• 2008

The urban is possessing of various landuses such as commercial, industrial, residential and official areas. All of these landuses is including the paved areas that are roads and parking lots. The NPS (nonpoint sources) pollutants are generally originated from pavement areas in urban by human activities. Especially the roads are stormwater intensive landuses because of high vehicle activities and high imperviousness. The main NPS pollutants from roads are particulates and metals from vehicles and pavements. The Korea MOE (Ministry of Environment) is developing the NPS control program to reduce the NPS pollutants from the basins. However, it is not easy to control the NPS because it has high uncertainty by characteristics of rainfalls and watersheds. Therefore, this research was conducted on characterizing the runoff and providing mean EMC from roads. The monitoring were performed for total 16 rainfall events from a road in Youngin City since 2006. The results show that the TSS is highly correlated with other pollutant parameters. The statistical regression models using TSS EMC have been developed to easily determine the EMC of other pollutant parameters.

• Journal of Environmental Impact Assessment
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• v.27 no.2
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• pp.170-180
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• 2018

Highland fields are concentrated in the Jaun area of Hongcheong-gun, a large amount of sediments are discharged from the highland fields. The sediment runoff affect the turbidity and water quality of the Soyang Lake, furthermore adversely affect water supply source of the capital region. There are several kinds of BMPs(Best management practices) to decrease the sedimentrunoff from the highland fields. Although construction cost of multistage sedimentation basins is very high, there is no actual survey data for the removal efficiency of suspended sediments and water quality in our country. In this study, stormwaterinflow and outflow of the multistage sedimentation basins were surveyed, and the removal efficiency of nonpoint source pollutants were analyzed. The stormwater survey results fortwo rainfall events show thatremoval efficiencies of SS, BOD and TP loads in the multistage sedimentation basins are 35%~62%, 24%~55%, 35%~58%, respectively. Although the measured efficiencies of the basins were lower than the theoretical efficiency, the proper operation and management can improve the removal rate of the basins. Turbid water problem in the upper parts of the Soyang River can be managed effectively through the additional installation of multistage sedimentation basins.

• Journal of Korean Society on Water Environment
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• v.32 no.1
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• pp.30-35
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• 2016

Urban areas generate large amounts of stormwater and non-point source (NPS) pollutants during rainfall events. These are caused by various land use runoffs, vehicular and human activities and increased impervious cover. The increased runoff and NPS pollutants cause water quality deterioration in the receiving waters and adversely affect the aqua-ecosystem. These environmental impacts could be reduced through the application of low impact development (LID) techniques. In Korea, more than 80% of the total rainfall occurs in summer and most of these were 10 mm or less. Therefore, if the LIDs developed were able to cope with rainfall of 10 mm and below, NPS management could be efficiently conducted. This research was performed to determine the effect of varying amounts of rainfall on the performance capability of an established infiltration and filtration facility (IF facility) that can be applied to Korea's common rainfall ranges. The IF facility area was 1.75% of the catchment area, however the facility treated more than 40% and 60% runoff volume and pollutant reduction respectively for a 10 mm rainfall. Lastly, higher volume and pollutant reduction could be attained when the LID area was at least 2% of the entire catchment.

• Journal of Wetlands Research
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• v.16 no.3
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• pp.423-429
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• 2014

Due to high imperviousness rates of the roads, various pollutants originated from vehicle activities and air depositions are accumulated on the road surfaces. The washed-off pollutants can deteriorate the water quality and destroy the aqua-ecosystems with their toxicity. Usually the roads are paved with asphalt and concrete, which can affect on the pollutant concentrations with different frictional forces. Therefore, this research is performed to evaluate the influences of different pavement type on discharged concentrations of pollutant. The results shows the first flush phenomenon was occurred on both pavement types. However, peak concentrations are higher in concrete pavement areas than asphalt pavement because concrete pavement has high contact area with vehicles. The EMCs(Event Mean Concentration) also shows high values in concrete paved roads. As a result of this research, it can be concluded the pavement type is also one of the important affecting factors on pollutant emissions from the roads.

• Korean Chemical Engineering Research
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• v.50 no.6
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• pp.980-987
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• 2012

Nonpoint source pollution causes leaks and overtopping, depending on the state of the sewer network as well as aggravates the pollution load of the aqueous water system as it is introduced into the sewer by wash-off. According, the need for efficient sewer monitoring system which can manage the sewage flowrate, water quality, inflow/infiltration and overflow has increased for sewer maintenance and the prevention of environmental pollution. However, the sewer monitoring is not easy since the sewer network is built in underground with the complex nature of its structure and connections. Sewer decontamination mechanism as well as pipe network monitoring and fault diagnosis of water network system on system analysis proposed in this study. First, the pollution removal pattern and behavior of contaminants in the sewer pipe network is analyzed by using sewer process simulation program, stormwater & wastewater management model for expert (XP-SWMM). Second, the sewer network fault diagnosis was performed using the multivariate statistical monitoring to monitor water quality in the sewer and detect the sewer leakage and burst. Sewer decontamination mechanism analysis with static and dynamic state system results showed that loads of total nitrogen (TN) and total phosphorous (TP) during rainfall are greatly increased than non-rainfall, which will aggravate the pollution load of the water system. Accordingly, the sewer outflow in pipe network is analyzed due to the increased flow and inflow of pollutant concentration caused by rainfall. The proposed sewer network monitoring and fault diagnosis technique can be used effectively for the nonpoint source pollution management of the urban watershed as well as continuous monitoring system.

• Journal of Korean Society of Disaster and Security
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• v.12 no.4
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• pp.1-13
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• 2019

Recently, as the occurrence frequency of sudden floods due to climate change increased, it is necessary to install the facilities that can cope with the initial stormwater. Most researches have been conducted on the design of facilities applying the Low Impact Development (LID) and the reduction effect on rainfall runoff to examine with 1D or 2D numerical models. However, the studies on the examination about flow characteristics and stability of pipe network systems were relatively insufficient in the literature. In this study, the stability of the pipe network system in rainwater storage tank was examined by using 3D numerical model, FLOW-3D. The changes of velocity and dynamic pressure were examined according to the number of rainwater storage tank and compared with the design criteria to derive the optimal design plan for a rainwater storage tank. As a results of numerical simulation with the design values in the previous study, it was confirmed that the velocity became increased as the number of rainwater storage tank increased. And magnitude of the velocity in pipes was formed within the design criteria. However, the velocity in the additional rainwater storage pipe was about 3.44 m/s exceeding the allowable range of the design criteria, when three or more additional rainwater storage tanks were installed. In the case of turbulence intensity and bottom shear stress, the bottom shear stress was larger than the critical shear stress as the additional rainwater storage was increased. So, the deposition of sediment was unlikely to occur, but it should be considered that the floc was formed by the reduction of the turbulence intensity. In addition, the dynamic pressure was also satisfied with the design criteria when the results were compared with the allowable internal pressure of the pipes generally used in the design of rainwater storage tank. Based on these results, it was suitable to install up to two additional rainwater storage tanks because the drainage becomes well when increasing of the number of storage tank and the velocity in the pipe becomes faster to be vulnerable to damage the pipe. However, this study has a assumption about the specifications of the rainwater storage tanks and the inflow of stormwater and has a limitation such that deriving the suitable rainwater storage tank design by simply adding the storage tank. Therefore, the various storage tank types and stormwater inflow scenarios will be asked to derive more efficient design plans in the future.

• Journal of Wetlands Research
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• v.21 no.4
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• pp.384-391
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• 2019

Nutrients in stormwater runoff have raised concerns regarding water quality degradation in the recent years. Low impact development (LID) technologies are types of nature-based solutions developed to address water quality problems and restore the predevelopment hydrology of a catchment area. Two LID facilities, infiltration trench (IT) and infiltration planter (IP), are known for their high removal rate of nutrients through sedimentation and vegetation. Long-term monitoring was conducted to assess the performance and cite the advantages and disadvantages of utilizing the facilities in nutrient removal. Since a strong ionic bond exists between phosphorus compounds and sediments, reduction of total phosphorus (TP) (more than 76%), in both facilities was associated to the removal of total suspended solids (TSS) (more than 84%). The efficiency of nitrogen in IP is 28% higher than IT. Effective nitrification occurred in IT and particulate forms of nitrogen were removed through sedimentation and media filters. Decrease in ammonium- nitrogen (NH₄-N) and nitrite-nitrogen (NO₂-N), and increase in nitrate-nitrogen (NO₃-N) fraction forms indicated that effective nitrification and denitrification occurred in IP. Hydrologic factors such as rainfall depth and rainfall intensity affected nutrient treatment capabilities of urban stormwater LID facilities The greatest monitored rainfall intensity of 11 mm/hr for IT yielded to 34% and 55% removal efficiencies for TN and TP, respectively, whereas, low rainfall intensities below 5 mm resulted to 100 % removal efficiency. The greatest monitored rainfall intensity for IP was 27 mm/hr, which still resulted to high removal efficiencies of 98% and 97% for TN and TP, respectively. Water quality assessment showed that both facilities were effective in reducing the amount of nutrients; however, IP was found to be more efficient than IT due to its additional provisions for plant uptake and larger storage volume.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.6
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• pp.137-148
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• 2008

There have been many cases of using wetlands as an alternative in controlling stormwater, treating mining leachate, and agricultural discharge, and so on, recently. The reality is, however, that the wetlands are not properly applicable because of the lack of enough longterm data for wetlands due to the difficulty of long-term monitoring. Therefore, this study tries to analyze the storage of Upo, Mokpo, Sajipo, and Jjokjibeul in Topyeong watershed using SWAT(Soil and Water Assessment Tool) model, one of the long-term runoff hydrologic model, for the purpose of generating the long-term data and analyzing the hydrologic behavior of wetlands based on the generated data. Also, the changes in runoff at the outlet are analyzed after applying the simulation of constructing washland in Topyeong watershed and the storage in Upo is analyzed. The result shows that the runoff at the outlet of the watershed is decreased in rainy season from July to August and increased in dry season from December to February. In addition, the analysis of Upo storage concludes that Upo can be influenced by the construction of the washland. The duration curve of washland is then analyzed in order to evaluate the wetland's sustainability in terms of washland and it appears that the runoff of washland is simulated to be less than that of the existing wetland. Moreover, runoffs of some washlands are simulated to be less even in wet season. These results lead to the fact that there should be further hydrologic management for constructed washland. Then, the changes in loads (TN and TP) because of constructing washland are analyzed. The result shows that the loads are reduced because of the construction. Also, the changes in loads due to the construction of buffer strips are analyzed to compare the load reductions caused by a washland. Finally, REMM model, a riparian management model, is applied to overcome the hydrologic ambiguousness of SWAT model, and then, the SWAT model results are compared to those of REMM.

• 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%.