• Korean Journal of Ecology and Environment
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• v.43 no.4
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• pp.492-502
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• 2010

The study objects were to analyze long-term and seasonal variations of nutrients (N, P), suspended solids, N:P ratios, algal chlorophyll, and trophic state along with general water quality parameters in four sampling sites including two intake tower sites supplying drinking water in Daechung Reservoir. For the analysis, we used water quality long-term data sampled during 1998~2007 by the Ministry of Environment, Korea. Interannual and seasonal trends in inflow and discharge near the intake tower facilities over the ten years were directly influenced by rainfall pattern. The distinct difference between wet year (2003) and dry year (2001) produced marked differences in water temperature, pH, dissolved oxygen, organic matter contents, nutrients, and these variables influenced algal biomass and trophic state. Values of TP varied depending on the year and locations sampled, but monthly mean TP always peaked during July~August when river inflow and precipitation were maxima. In contrast, TN varied little compared to TP, indicating lower influence by seasonal flow compared to phosphorus. The number of E. coli were highest in Site 2 (Chudong intake tower) and varied largely, whereas at other sites, the numbers were low and low variations. Contents of chlorophyll-${\alpha}$ (CHL), as an estimation of primary productivity, varied largely depending on the year and season. The maximum of CHL occurred at Muneu intake tower (S4) during 2006 when the precipitation and inflow were lowest. In contrast, another CHL peak was observed in Site 2 (Chudong intake tower) in 2006 when one of the largest typoons (Ewinia) occurred and river runoff were maximum. So the CHL maxima were associated with both wet year (high flow, high nutrient supply) and dry year (low flow, nutrient supply by littoral zone). Such conditions influenced trophic states, based on Trophic State Index of nutrients and CHL. Based on all analyses, we can provide some clues for management and protection strategies of two intake tower sites.

• Tunnel and Underground Space
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• v.13 no.5
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• pp.353-361
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• 2003

For RMR and Q rock mass classification at the design and construction stage, evaluation of groundwater condition is usually based upon the experience due to the restriction of available methods. Based on the results of Taejon LNG Pilot Cavern which acquire joint water pressure, inflow rate of ground water and hydraulic conductivity model, estimates from numerical analysis and analytical solutions were compared to verify each evaluation method. As the result, the Raymer(2001) approach was found to be efficient for estimating inflow rate and corresponding value.

• Journal of Korean Society on Water Environment
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• v.24 no.2
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• pp.221-229
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• 2008

This study revised a model for hydrologically analyzing rainwater harvesting facilities considering their rainfall-runoff properties and the data available. This model has only a few parameters, which can be estimated with rather poor measurements available. The model has a non-linear module for rainfall loss, and the remaining rainfall excess (effective rainfall) is assumed to be inflow to the storage tank. This model has been applied for the rainwater harvesting facilities in Seoul National University, Korea Institute of Construction Technology, and the Daejon World Cup Stadium. As a result, the runoff coefficients estimated were about 0.9 for the building roof as a rainwater collecting surface and about 0.18 for the playground. This result is coincident with that for designing the rainwater harvesting facilities to show the accuracy of model and the simulation results.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.1323-1327
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• 2005

도시에서 배출되는 오수나 우수를 모아서 하수처리장 또는 방류수역까지 유하시키는 역할을 하는 관거시설은 하수도 시설의 근간으로서 일반주민의 일상생활과 밀접한 관계가 있기 때문에 시설의 실태를 충분히 파악하여 적절한 유지관리를 시행하지 않으면 안된다. 그러나 지금까지 하수관거에 대한 인식부족으로 인하여 유지관리는 물론 현 실태 또한 제대로 인식 되지 않았다. 따라서 본 연구에서는 인천지역의 승기천 유역을 대상으로 I/I분석 및 예측, 이에 따른 오염 저감 방안을 연구하였다. 본 연구는 승기천 유역 내 주요지점에 대한 관거 I/I 및 하수의 누수량을 조사하기 위하여 고정식 4개 지점(풍림지점, 우성지점, 동막지점, 성주지점)에 대해 하수처리장의 유입수량 및 수질의 영향을 파악하고 해당지역의 관거 문제점을 도출하여 정비방향을 모색하고, 사업시행에 따른 효과분석에 활용하며 성과분석 목표를 수립하기 위한 기초자료를 제공하는데 연구 목적이 있다.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1410-1414
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• 2006

Infiltration and Inflow(I/I) through the old or broken sewer are caused falling efficiency of sewage treatment plants. Recently, to solve these problems maintenance work of sewer pipes is progressing and sewer flow is metered for I/I survey. In this paper, metered sewer data at GyeongGi-Do H city for two years are analyzed by ToSS program. And this paper suggest particle use of sewer flow much data for many years.

• Journal of Korean Society of Water and Wastewater
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• v.8 no.3
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• pp.1-8
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• 1994

In the general process of design for aerobic digestion, the design for field plant of which inflow pattern is continuous inflow is performed using the results from lab scale batch reactor. However, the recent researchers reported that the general designs were performed as over-estimated, Therefore, in this study, laboratory batch experiments were carried out at $20^{\circ}C$ and pH 7.5 on the aerobic digestion of waste activated sludge at different solid levels. This treatise could consider the negligence about effective digestion periods the usage of VSS as solid concentration, and the effect of initial solid concentration of solid degration rate coefficient($k_d$) as reasons of the overestimated design, and showed the scheme of how to design for aerobic digestion from batch experiment.

• Journal of Biosystems Engineering
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• v.32 no.2 s.121
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• pp.115-120
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• 2007

The adhesive performance of marine mussel extract was compared with that of the commercial medical adhesives for fastening biotissue (SIS) bandages. Joints bonded with mussel extract showed stronger strength than those bonded with other commercial adhesives. The bonding strength was much improved when the moisture in the Joint was reduced using superporous hydrogel regardless of curing time under humid condition ($37^{\circ}C$ and 91% relative humidity). Water inflow into the SIS joint seemed to degrade the performance of mussel extracts adhesive especially for the joints of short period of curing time. The strength of SIS joints coated with surgical sealant was well maintained after being exposed to water inflow.

• Proceedings of the Korea Water Resources Association Conference
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• 2001.05a
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• pp.45-51
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• 2001

The daily inflow is apparently one of nonlinear and complicated phenomena. The nonlinear and complexity make it difficult to model the prediction of daily flow, but attractive to try the neural networks approach which contains inherently nonlinear schemes. The study focuses on developing the forecasting models of daily inflows to a large dam site using neural networks. In order to reduce the error caused by high or low outliers, the back propagation algorithm which is one of neural network structures is modified by combining a regression algorithm. The study indicates that continuous forecasting of a reservoir inflow in real time is possible through the use of modified neural network models. The positive effect of the modification using tole regression scheme in BP algorithm is showed in the low and high ends of inflows.

• Journal of Korea Water Resources Association
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• v.52 no.11
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• pp.947-950
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• 2019

The main feature of this paper is to provide a driving control strategy to improve the primary clarifier treatment efficiency in the initial rainfall inflow. With the recent development of IoT technology and sensing technology, the basis for operation control of wastewater treatment facilities has been improved. As a result of improving the efficiency of treatment of primary clarifier using on-line measurement results, it is possible to minimize the outflow of untreated sewage and contribute to the improvement of operation efficiency of wastewater treatment plants.

• Journal of the korean society of oceanography
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• v.33 no.3
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• pp.41-52
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• 1998

A seasonal circulation pattern in the eastern Yellow Sea (EYS) is suggested from the water mass analysis and geostrophic calculation using the hydrographic data collected by National Fisheries Research and Development Institute during the years of 1970 to 1990. This research focuses on the presence of inflow of warm (and saline) waters into EYS in summer. EYS is divided into two regions in this paper: the west coast of Korea (WCK) and the central Yellow Sea (CYS). In CYS, waters are linked with warm waters near Cheju Island in winter, but with cold waters from the north in summer (in the lower layer). It is not simple to say about WCK because of the influences of freshwater input and tidal mixing. Nevertheless, water mass analysis reveals that along WCK, waters have the major mixing ratios (40-60%) of warm waters in summer, while the dominant mixing ratios (50-90%) of cold waters in winter. Such a seasonal change of water mass distribution can be explained only by seasonal circulation. In winter, warm waters flow northward into CYS and cold waters flow southward along WCK. In summer, warm waters flow northward along WCK and cold waters flow southward into CYS. This circulation pattern is supported by both statistical analysis and dynamic depth topography. Accordingly, Yellow Sea Warm Current may be defined as the inflow of warm waters to CYS in winter and to WCK in summer.