• Proceedings of the Korea Water Resources Association Conference
• /
• 2009.05a
• /
• pp.966-970
• /
• 2009

경기도 용인시, 오산시와 화성시 지역의 농업용수와 공업용수의 공급원으로 이용되고 있는 신갈호는 현재 유입하천으로부터 미처리된 도시하수, 공장 폐수, 축산 폐수 등의 점오염원 및 도시 지역 불투수층에 쌓여있는 오염물질인 비점오염원이 무분별하게 유입되어 수질이 매우 악화되어 용수로의 사용이 어려운 지경에 달하였으며, 자연정화능력도 감소하는 등 심각하게 오염되었다. 또한 최근에는 신갈호 유역의 개발에 따른 토지이용 변화로 신갈호 유역의 총오염부하량이 증가하고 있는 실정이다. 따라서 본 연구에서는 현재 날로 심각해지는 신갈호 유입하천의 비점오염원 조사를 통해 신갈호 및 유입하천의 기초데이터의 확충 및 현황 파악을 하고자 하였다. 본 연구에서는 강우 시 신갈호로 유입되는 3개의 유입지천인 신갈천(SG), 지곡천(JK), 공세천(KS)에서 비점오염부하량을 산정함으로써 강우 시 호소로 유입되는 총오염부하량 및 비점오부하량의 비율을 알아보고자 하였다. 강우사상에 따른 총 오염물질 부하량은 EMC 농도를 구한 후 총 유출유량을 곱하고 총 강우지속시간을 곱하여 산정하였다. 조사결과 강우기에 있어서 거의 모든 항목의 농도는 평수기보다 매우 높은 수치를 나타냈다. 특히 SS 농도는 토사의 하천유입으로 인해 다른인자에 비해 큰 변동폭을 나타내었으며, COD와 T-P는 토양입자에 흡착되어 함께 이동하기 때문에 SS와 밀접한 관계를 가졌다. 강우시의 각 유입하천별 오염부하 기여율은 SG의 경우 SS 74.1%, BOD 64.4%, COD 65.7%, T-N 63.8%, T-P 73.8%를 나타내었다. JK의 경우 SS 25.4%, BOD 31.5%, COD 30.5%, T-N 32.5%, T-P 24.2% 였고, KS의 경우 SS 0.5%, BOD 4.1%, COD 3.8%, T-N 3.7%, T-P 2.0%를 나타내었다. 강우시의 각 유입하천별 오염부하 기여율을 평수기때의 오염부하 기여율과 비교하였다. 비교결과 SS의 경우는 SG가 강우시에 74%, 평수기에 83%, BOD의 경우는 강우시 64%, 평수기 80%, T-N은 강우시 64%, 평수기에 84%, T-P의 경우는 강우시 74%, 평수기에 82%로 모든 항목에서 평수기에 신갈천이 신갈호의 오염부하에 미치는 영향이 큰 것으로 나타났는데, 이는 강우시 지곡천의 기여율이 평수기 보다 상대적으로 높아지기 때문인 것으로 판단된다.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.6 no.4
• /
• pp.37-44
• /
• 2003

In order to evaluate the contribution of MMSTP operation to the improvement of marine water quality of Mokpo harbour and to estimate the change of pollution loads flowing into Mokpo harbour after the operation of Mokpo Municipal Sewage Treatment Plant (MMSTP), the pollution loads flowing into Mokpo harbour from land in dry weather were surveyed and estimated on the bases of the seasonal flow rates and the seasonal water qualities of streams and effluents located around Mokpo harbour from summer, 1997 to spring, 1998 before the operation of MMSTP, and the pollution loads of the inflow and the effluent of MMSTP were also surveyed and estimated from winter, 1998 to spring, 1999 after the operation of MMSTP. The treatment rates of MMSTP were shown to be about 49% in COD, 76% in TSS, 79% in VSS, 3% in T-N, 7% in DIP, 29% In T-P and -32% in DIN. The change rates of pollution loads flowing into the inner harbour of Mokpo due to the operation of MMSTP were shown to be about 56% in COD, 78% in TSS, 84% in VSS, 45% in DIN, 22% in T-N, 34% in T-P and -14% in DIP The contribution rates of MMSTP operation to the reduction of total pollution loads flowing into the entire Mokpo harbour were found to be about 3% in COD, 3% in TSS, 5% in VSS, 1% in DIP, 3% in T-P and -1% in DIN.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.8 no.2
• /
• pp.154-160
• /
• 2000

Landfill gas (LFG) utilization in old landfill was estimated using LFG models. The results showed that Scholl Canyon model best described the LFG generation. LFG was extracted more than the amount of natural production which caused air inflow from outside that resulted in dilution of methane concentration and increase of oxygen concentration. It was negative for the LFG utilization. Therefore, to use LFG, the plan of stabilization by LFG extraction should be ineffective. The use of LFG will have no problem if LFG is extracted less than the amount of natural production which was estimated based on modeling. At 8 years elapsed from landfill, now, the amount of natural landfill gas production was decreased sharply. The plan for using LFG from old landfill is feasible if LFG is used for the less than the amount of natural production as a small scale even though for the aspect of efficiency, it was less economic than use of LFG just after closing landfilling and it was helpful for stabilization of landfill by LFG extraction.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.24 no.2
• /
• pp.56-66
• /
• 1982

This study was carried out in order to estimate water losses in irrigation canals, which may be used to evaluate the water requirement for irrigation projects. The conveyance losses were measured by the inflow-outflow method, the seepage losses were measured by the ponding method, and the operation losses in the course of irrigation were calculated by comparing the two kinds of losses. The results obtained in this experiment were as follows; 1. Conveyance losses per unit area of wetted perimeter by the main irrigation canal, the secondary irrigation canal and the tributary irrigation canal, were 1.399${\times}10^{-5}m^3/sec/m^2$, 5.154${\times}10^{-5}m^3/sec/m^2$, and 2.67${\times}10^{-5}m^3/sec/m^2$ respectively in the Goong-sa area. And they were 1.934${\times}10^{-5}m^3/sec/m^2$, 2.149${\times}10^{-5}m^3/sec/m^2$, and 4.558${\times}10^{-5}m^3/sec/m^2$ respectively in the Seong-dug area. 2. Seepage losses per unit area of wetted perimeter by the secondary irrigation canal and the tributary irrigation canal, were 2.180${\times}10^{-6}m^3/sec/m^2$ and 2.168${\times}10^{-6}m^3/sec/m^2$ in the Goong-sa area, 1.150${\times}10^{-6}m^3/sec/m^2$ and 1.084${\times}10^{-6}m^3/sec/m^2$ in the Seong-dug area respectively. 3. Operation losses per unit area of wetted perimeter by the secondary irrigation canal and the tributary irrigation canal, were 4.936${\times}10^{-5}m^3/sec/m^2$ and 2.453${\times}10^{-5}m^3/sec/m^2$ in the Goong-sa area, 2.034${\times}10^{-5}m^3/sec/m^2$ and 4.450${\times}10^{-5}m^3/sec/m^2$ in the Seong-dug area respectively. 4. Conveyance, seepage and operation losses in the Goong-sa area were 6.7%, 94.6%, and 14.0% more than those in the Seong-dug area. Operation losses amount to about 17 times as much as seepage losses in the Goong-sa area and about 29 times in the Seong-dug area. 5. The seepage losses depend much on the soil texture, ranging from 7.437${\times}10^{-7}m^3/sec/m^2$ to 2.430${\times}10^{-6}m^3/sec/m^2$. 6. Water loss rates in the main irrigatin canal, the secondary irrigation canal and the tributary irrigation canal, were estimated as 8.49%, 37.27% and 9.81% respectively in the Goong-sa area. And they were estimated as 15.10%, 32.67% and 13.78% respectively in the Seong-dug area.

• Journal of Korea Water Resources Association
• /
• v.43 no.5
• /
• pp.445-453
• /
• 2010

Energy loss at manholes, often exceeding friction loss of pipes under surcharged flow, is considered as one of the major causes of inundation in urban area. Therefore, it is necessary to analyze head losses at manholes, especially in case of surcharged flow. Hydraulic experimental apparatus which can change the manhole shape (square, circular) were installed for this study. In the experiments, two inflows ($Q_1,\;Q_2$) were varied from 0 to $4{\ell}$/sec and 15 combinations were tested in total. The flow ratios $Q_2/Q_3$ were varied from 0 to 1 for a total flow $Q_3$ ($Q_3=Q_1+Q_3$) of 2, 3, and $4{\ell}$/sec, respectively. The variation of head losses were strongly influenced by the lateral inflow because the head loss coefficient increases as the flow ratio $Q_2/Q_3$ increases. There was no significant difference of head loss between square manhole and circular one, and also no large variation of head loss as discharges change. The relation equations between K and $Q_2/Q_3$ were suggested in this paper.

• Journal of Environmental Policy
• /
• v.10 no.1
• /
• pp.71-91
• /
• 2011

The purpose of this paper is to estimate the environmental performance of 29 Chinese provinces by adopting the advanced measurements, integrated pollution intensity index, IPI, which can be computed using Data Envelopment Analysis(DEA) techniques. This index has the advantage of accounting for multiple resources used, good outputs produced and pollutants emitted simultaneously. The result obtained using the methodology shows the obvious evidence that provinces located around eastern area of China take relatively low levels and these phenomenons have been clearly observed throughout the sample period 1998~2007. The estimated index can be interpreted that the environmental burden in China has been steadily decreased as economic growth. This paper also tries to figure out the relationship among IPI, income levels, economic structures, the level of environmental regulations and FDI inflow. The estimated relationship between IPI and income per capita predicts improving environmental performance with increasing income levels. This explains the improvement in IPI which is simultaneously observed with income increases. According to the 'pollution haven hypothesis', many researches have been concerned the possibility that a large amount of foreign capital has been invested in China to avoid the strict environmental standards in advanced countries. However, the estimated coefficients in all model specifications take negative sign with IPI and highly statistical significant. This is a indication that there are positive impacts of foreign investments on IPI by adopting clean and high technologies from advanced countries.

• Journal of Wetlands Research
• /
• v.14 no.4
• /
• pp.519-535
• /
• 2012

In order to establish a rainfall-runoff model, calibration of hydrological parameters for the model is very important. Especially, Curve Number(CN), estimated by NRCS method, is a main factor to apply unit hydrograph theory to calculation of peak discharge. For using NRCS method, it is needed selecting AMC because CN is strongly connected with that. In this study, we focus our concern on finding a applicable standard for selecting AMC for CN. For this, three dams which are Boryeong, Habchon, Namgang are selected as target basins to use observed data including rainfall and dam inflow. As a result of this research, it is found that CN must be included as a calibrated parameter to calculate effective rainfall for the rainfall-runoff model. Also, it is preferred to use PWRMSE of HEC-HMS program as a objective function for optimizing hydrological parameters. From the analyzing result of variation of AMC for peak discharge, it is recommended to apply AMC-III to estimation of CN for calculating effective rainfall of design hydrograph.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.12
• /
• pp.668-678
• /
• 2017

In this study, the hydrological and meteorological drought index with precipitation as a major factor were calculated, and various analyses of hydrological drought were conducted. The Modified Surface Water Supply Index (MSWSI) was applied to the hydrological drought index and Standardize Precipitation Index (SPI) was used to estimate the meteorological drought index. The target area for the estimation is the dam area among MSWSI categories. The 4001 basin with 43 years data from 1975 to 2017 was analyzed for the drought occurrence status and time series plotted with the monthly SPI and MSWSI. For the dam watershed based on the precipitation that has the role of a water supply in the hydrological cycle, correlation analysis of precipitation, dam inflow, and stream flow was performed by the monthly and moving average (2~9 months), and the correlation between meteorological and hydrological index by monthly and moving average (3, 6 months) was then calculated. The result of multifaced analysis of the hydrological drought index and meteorological drought index is believed to be useful in developing water policy.

• Journal of Distribution Science
• /
• v.11 no.10
• /
• pp.73-79
• /
• 2013

Purpose - This study examines the impact of oil price volatility on economic activities in Korea. The new millennium has seen a deregulation in the crude oil market, which invited immense capital inflow into Korea. It has also raised oil price levels and volatility. Drawing on the recent theoretical literature that emphasizes the role of volatility, this paper attends to the asymmetric changes in economic growth in response to the oil price movement. This study further examines several key macroeconomic variables, such as interest rate, production, and inflation. We come to the conclusion that oil price volatility can, in some part, explain the structural changes. Research design, data, and methodology - We use two methodological frameworks in this study. First, in regards to the oil price uncertainty, we use an Exponential-GARCH (Exponential Generalized Autoregressive Conditional Heteroskedasticity: EGARCH) model estimate to elucidate the asymmetric effect of oil price shock on the conditional oil price volatility. Second, along with the estimation of the conditional volatility by the EGARCH model, we use the estimates in a VECM (Vector Error Correction Model). The study thus examines the dynamic impacts of oil price volatility on industrial production, price levels, and monetary policy responses. We also approximate the monetary policy function by the yield of monetary stabilization bond. The data collected for the study ranges from 1990: M1 to 2013: M7. In the VECM analysis section, the time span is split into two sub-periods; one from 1990 to 1999, and another from 2000 to 2013, due to the U.S. CFTC (Commodity Futures Trading Commission) deregulation on the crude oil futures that became effective in 2000. This paper intends to probe the relationship between oil price uncertainty and macroeconomic variables since the structural change in the oil market became effective. Results and Conclusions - The dynamic impulse response functions obtained from the VECM show a prolonged dampening effect of oil price volatility shock on the industrial production across all sub-periods. We also find that inflation measured by CPI rises by one standard deviation shock in response to oil price uncertainty, and lasts for the ensuing period. In addition, the impulse response functions allude that South Korea practices an expansionary monetary policy in response to oil price shocks, which stems from oil price uncertainty. Moreover, a comparison of the results of the dynamic impulse response functions from the two sub-periods suggests that the dynamic relationships have strengthened since 2000. Specifically, the results are most drastic in terms of industrial production; the impact of oil price volatility shocks has more than doubled from the year 2000 onwards. These results again indicate that the relationships between crude oil price uncertainty and Korean macroeconomic activities have been strengthened since the year2000, which resulted in a structural change in the crude oil market due to the deregulation of the crude oil futures.

• Journal of Korean Society on Water Environment
• /
• v.28 no.3
• /
• pp.375-383
• /
• 2012

Soil erosion has been emphasized as serious environmental problem affecting water quality in the receiving waterbodies. Recently, Best Management Practices (BMPs) have been applied at a field to reduce soil erosion and its effectiveness in soil erosion reduction has been monitored with various methods. Although monitoring at fields/watershed outlets would be accurate way for these ends, it is not possible at some fields/watersheds due to various limitations in direct monitoring. Thus modeling has been suggested as an alternative way to evaluate effects of the BMPs. Most models, which have been used in evaluating hydrology and water quality at a watershed, could not reflect rainfall intensity in runoff generation and soil erosion processes. In addition, source codes of these models are not always public for modification/enhancement. Thus, runoff-sediment evaluation system using hourly rainfall data and vegetated filter strip (VFS) evaluation module at field level were developed using open source MapWindow GIS component in this study. This evaluation system was applied to Bangdongri, Chuncheonsi to evaluate its prediction ability and VFS module in this study. The NSE and $R^2$ values for runoff estimation were 0.86 and 0.91, respectively, and measured and simulated sediment yield were 15.2 kg and 16.5 kg indicating this system, developed in this study, can be used to simulate runoff and sediment yield with acceptable accuracies. Nine VFS scenarios were evaluated for effectiveness of soil erosion reduction. Reduction efficiency of the VFS was high when sediment inflow was small. As shown in this study, this evaluation system can be used for evaluation BMPs with local rainfall intensity and variations considered with ease-of-use GIS interface.