• 상하수도학회지
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• 제22권6호
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• pp.619-625
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• 2008

Urban sewer systems are designed to operate in open-channel flow regime and energy loss at square manholes is usually not significant. However, the energy loss at surcharged manholes is considered as one of the major causes of inundation in urban area. Therefore, it is necessary to analyze the head loss associated with manholes, especially in surcharged flow. Hydraulic experimental apparatus which can change the manhole inner profile(CASE I, II, III, and IV) and the invert types(CASE A, B, C) were installed for this study. The experimental discharge was $16{\ell}/sec$. As the ratio of b/D(manhole width/inflow pipe diameter) increases, head loss coefficient increases due to strong horizontal swirl motion. The head loss coefficients for CASE I, II, III, and IV were 0.46, 0.38, 0.28 and 0.37, respectively. Side covers increase considerably drainage capacity at surcharged square manhole when the ratio of d/D(side cover diameter/inflow pipe diameter) was 1.0. The head loss coefficients for CASE A, B, and C were 0.45, 0.37, and 0.30, respectively. Accordingly, U-invert is the most effective for energy loss reduction at surcharged square manhole. This head loss coefficients could be available to evaluate the urban sewer system with surcharged flow.

• 환경영향평가
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• 제22권1호
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• pp.99-107
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• 2013

This study is an impact assessment of building blocks on urban inundation depth and area. LiDAR data is used to generate two original data set in terms of DEM with $5{\times}5$ meter and building block elevation layer of the study drainage area in Cheongju and then the building block elevation layer is modified again to the mesh data with same size to DEM. Two-dimensional inundation analysis is carried out by applying 2D SWMM model. The inundation depth calculated by using the building block elevation layer shows higher reliability than the DEM. This is resulted from the building block interference to surface flow. In addition, the maximum flooded area by DEM is two times wider than the area by building block layer. In the case of the surface velocity, the difference of velocity is negligible in either DEM or building block case in the low building impact zone. However, If the impact of building on the surface velocity was increase, the gap of velocity was significant.

• 한국물환경학회지
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• 제23권5호
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• pp.748-755
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• 2007

To develop an efficient pump operating rule for a retard basin, it is necessary to estimate inflow to the retard basin accurately which is affected by the backwater effect at the outlet of the conduit. The magnitude of the backwater effect is dependent on the water depth of a retard basin; however, the depth is determined by the amount of inflow and outflow. Thus, a real time simulation system that is able to simulate urban runoff and the pump operation with the consideration of the backwater effect is required to estimate the actual inflow to a retard basin. With this system, the efficient pump operating rule can be developed to diminish the possible flood damage on urban areas. In this study, a realtime simulation system is developed using the SWMM 5.0 DLL and Visual Basic 6.0 equipped with EXCEL to estimate inflow considering the backwater effect. The realtime simulation can be done by updating realtime input data such as minutely observed rainfall and the depth of a retard basin. Using those updated input data, the model estimates actual inflow, the amount of outflow discharged by pumps and gates, the depth of each junction, and flow rate at a sewer pipe on realtime basis. The developed model was applied to the Joonggok retard basin and demonstrated that it can be used to design a sewer system and to estimate actual inflow through the inlet sewer to reduce the inundation risk. As results, we find that the model can contribute to establish better operating practices for the pumps and the flood drainage system.

• 물과 미래
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• 제26권3호
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• pp.125-135
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• 1993

본 연구의 목적은 도시유역에 적합한 유량 및 수질 모형을 선택하고 그 모형을 임의의 대상유역에 적용하여 그 적합성을 판정하는 데 있다. 본 연구를 위하여 선택된 모형은 EPA의 SWMM 모형으로, 이 모형은 도시유역의 유량 및 수질, 특히 NPS(non-point source) 오염물의 배출의 모의에 적합한 모형이며, 실제 적용에 있어서는 지표면유출을 위해서는 Runoff Block을, 관거 추적을 위해서는 Transport Block을 사용하였다. 본 연구의 적용대상유역은 전형적인 도시유역인 서울시 동대문구 용두유수지 유역이며, 이 유역을 위한 기존의 4개의 연속유량 측정치와 2개의 연속수질 측정치를 가지고 모의를 수행하였다. 유량 및 수질, 특히 NPS 부하량의 검정을 첨두치, 첨두시간, 유출 및 배출 용적과 그들의 상대오차에 대하여 수행하였으며, 그 결과, SWMM 모형은 유출 및 NPS 오염물 배출 모두를 모의하는데 적합한 모형임이 밝혀졌다. 본 연구의 결과는 차후 도시유역의 유출과 NPS 오염물 배출간의 상관관계의 분석 및 그를 통한 유역의 오염물의 년, 월, 부하량의 산정을 통한 물질수지계산 방법의 연구에 바탕이 될 수 있을 것이다.

• 한국수자원학회논문집
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• 제40권1호
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• pp.25-38
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• 2007

본 연구에서는 지표면 유출의 시간적 변화와 공간적 분포를 모의할 수 있는 격자기반의 도시유역 지표면 유출모형을 개발하였다. 개발된 모형에서는 지표면 유출의 메카니즘을 연속방정식과 Manning식을 결합한 비선형저류방정식으로 표현하고 있으며, 대상유역을 일정한 크기의 격자로 구성하고 개개의 격자마다 유출해석을 위한 지형정보와 수문정보를 입력하여 격자별 유출량을 계산 추적하게 된다. 본 모형을 이용하여 가상유역 및 실제 도시유역인 군자 배수구역에 대해서 시공간적인 유출양상을 모의해 봄으로써 모형의 적용성을 검토하였다. 이동강우에 대한 유출량의 변화, 유입구 설치에 따른 유출양상의 변화, 확률강우량에 대한 Huff 분위별 유출양상의 변화 등 도시지역의 유출특성을 분석하여 그 결과를 제시하였다.

• 한국환경복원기술학회지
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• 제17권3호
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• pp.1-11
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• 2014

Recently, major cities in Korea are suffering from frequent urban flooding caused by heavy rainfall. Such urban flooding mainly occurs due to the limited design capacity of the current drainage network, which increases the vulnerability of the cities to cope with intense precipitation events brought about by climate change. In other words, it can be interpreted that runoff exceeding the design capacity of the drainage network and increased impervious surfaces in the urban cities can overburden the current drainage system and cause floods. The study presents the green roof as a sustainable solution for this issue, and suggests the pre-design using the LID controls model in SWMM to establish more specific flood prevention system. In order to conduct the computer simulation in connection with Korean climate, the study used the measured precipitation data from Cheonan Station of Korea Meteorological Administration (KMA) and the forecasted precipitation data from RCP 8.5 scenario. As a result, Extensive Green Roof System reduced the peak runoff by 53.5% with the past storm events and by 54.9% with the future storm events. The runoff efficiency was decreased to 4% and 7%. This results can be understood that Extensive Green Roof System works effectively in reducing the peak runoff instead of reducing the total stormwater runoff.

• 한국물환경학회지
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• 제23권4호
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• pp.490-497
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• 2007

A Combined sewer overflows (CSOs) are themselves a significant source of water pollution. Therefore, the control of urban drainage for CSOs reduction and receiving water quality protection is needed. Examples in combined sewer systems include downstream storage facilities that detain runoff during periods of high flow and allow the detained water to be conveyed by an interceptor sewer to a centralized treatment plant during periods of low flow. The design of such facilities as stormwater detention storage is highly dependant on the temporal variability of storage capacity available (which is influenced by the duration of interevent dry periods) as well as the infiltration capacity of soil and recovery of depression storage. As a result, a continuous approach is required to adequately size such facilities. This study for the continuous long-term analysis of urban drainage system used analytical probabilistic model based on derived probability distribution theory. As an alternative to the modeling of urban drainage system for planning or screening level analysis of runoff control alternatives, this model have evolved that offer much ease and flexibility in terms of computation while considering long-term meteorology. This study presented rainfall and runoff characteristics of the subject area using analytical probabilistic model. This study presented the average annual COSs and number of COSs when the interceptor capacity is in the range $3{\times}DWF$ (dry weather flow). Also, calculated the average annual mass of pollutant lost in CSOs using Event Mean Concentration. Finally, this study presented a decision of storage volume for CSOs reduction and water quality protection.

• 한국환경복원기술학회지
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• 제3권4호
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• pp.11-21
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• 2000

This study was aimed to establish different drainage types of soil media on the plant growing in rooftop. For this study, experiment plots were installed on the roof of Social Science building, Chongju University, from April, 1998 to September, 1999. (1) Sand and sandy loam as base and check soils, (2) vermiculite as a inorganic soil media (3) "humus sawdust" and "burned rice hull" as organic soil media were used by various mixing ratio Zoysia japonica, was selected for the experiment. The results of this study are as follows : L5B3S2 and L5H3S2 of bad drainage character with a plastic drainage plate combination caused good growth effect on Zoysia japonica examined in 3 types of drainage layer with 5 types of soil media. From this result, it could be suggested that combined design of plastic drainage plate with 2 soil types - L5B3S2 and L5H3S2 - be desirable composition for regarding weight load and plant growth.

• 한국지반환경공학회 논문집
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• 제24권11호
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• pp.25-31
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• 2023

대표적인 비탈면 배수공법인 수평배수공은 비탈면 내 간극수압을 감소시키기 위해 국내외에서 다수 활용하고 있다. 이에 따라 다양한 연구들이 선행되어 왔으나, 수평배수공의 수량을 산정하기 위한 명확한 설계기준이 없어 획일적으로 시공되고 있다. 따라서 본 논문에서는 다양한 수평배수공의 배수성능과 영향인자에 대한 메커니즘을 규명하고자 현장토를 이용하여 모형토조실험을 수행하였다. 또한, 배수재 형상이나 크기에 따른 배수성능을 비교하고자 입도분포가 다른 시료에서의 유출량 결과를 비교 및 검토하였다. 정상류 상태에서 배수실험을 확인하기 위해 유출량을 측정한 결과, 모든 시료에서 최소 3분에서 최대 15분 뒤 일정한 속도로 배수되는 것을 확인하였다. 조립질 지반에서 단일 시간당 유출되는 양(단위 유출량)으로 비교한 경우, 배수재 형상과 크기에 따른 배수효과가 상이하여 배수성능에 영향을 미치는 것을 확인하였다. 향후 세립질 지반에서의 배수 성능실험과 수량을 결정하기 위한 기초자료로 충분히 활용될 수 있을 것으로 기대된다.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2007년도 정기총회 및 학술발표대회
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• pp.211-214
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• 2007

The purpose of this study was to establish the basic information for natural drainage capacity assessment in urban area. We sorted midium watershed of Han river and Nak-dong river, and selected 30 rainfall events during 1995 to 2000 according to high level of damage. The inundated area showed high watershed slope about 25% and it indicated the greatest damage around the watershed located in 200-300m of altitude. Besides, the great damage by inundation was occurred in the mountainous agriculture region, where the forest scale was high and the urbanization was being progressed gradually. However, inundated area was small in case of grassland, water tone such as riparian area, bare ground and wetland. Moreover, the inundated area was different according to river shape and characteristics of river distribution such as the density of the stream order, conservation constant of the river system, and the number of undulations in the watershed. Therefore, it showed that land use, river shape and distribution characteristics of stream influence on inundation.