• Journal of Korean Society of Environmental Engineers
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• v.22 no.2
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• pp.355-362
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• 2000

The objective of this paper is to estimate the pollutant load based on event mear concentrations(EMC) in industrial complex. Eight sub-basins in the Chongju industrial complex were selected for sampling and study with different characteristics during the period from June 1997 to August 1998. During the storm events, measured EMC ranges of $BOD_5$, COD, SS, TKN, TP, HEM, $NO_3-N$, $PO_4-P$, Cr, Pb, Cu and Fe in the industrial complex watersheds were 11~176mg/L, 40~502mg/L, 23~633mg/L, 104~20.9mg/L, 0.22~7.51mg/L, 12.7~548.7mg/L, 0.06~2.66mg/L, 0.12~3.39mg/L, 0.01~0.50mg/L. 0.02~0.42mg/L, 0.01~0.15mg/L and 1.29~11.51mg/L respectively. And the calculated annual average pollutant unit loadings of $BOD_5$ COD, SS, TKN, $NO_3-N$, $PO_4-P$, TP, HEM, Cr, Pb, Cu and Fe were 374.4kg/ha/yr 924.1kg/ha/yr, 983.6kg/ha/yr, 48.8kg/ha/yr, 8.1kg/ha/yr, 9.7kg/ha/yr, 17.8kg/ha/yr 943.0kg/ha/yr, 0.7kg/ha/yr, 0.9kg/ha/yr, 0.3kg/ha/yr and 28.9kg/ha/yr, respectively.

• Journal of Wetlands Research
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• v.10 no.2
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• pp.129-141
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• 2008

This study analyzed and assessed the water quality of a small urban stream in the apartment complex of Yewol-Dong, Buchun-Si at Korea. The flows in the stream due to the interceptions of sewage and normal flow are usually low and the water quality and offensive odor problems by inflows of the sewage and other pollutants are occurred in the study area. Therefore we intended to monitor and identify the water quality conditions. Based on this, we simulated water quality using QUAL2E model and investigated water quality characteristics for the future. As the results, we found that the water quality depended on the inflows of point and non-point sources and so it is important to maintain instream flow for improvement of water quality problem and to intercept point and non-point sources in this study area.

• Journal of Wetlands Research
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• v.9 no.3
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• pp.25-34
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• 2007

We analyzed flood runoff and flood characteristics of an small urban river basin which is in an apartment complex in Yewol-Dong, Buchun-Si, Gyunggi-Do. This discharge normally flows a little by intercepting sewer and interception of pollutants. However in flood period it looks like risk of flood damage by high flood discharge and increase of flood elevation. After appling the analysis model on urban runoff, using the GIS data and cross section at the basin, and then we studied the degree of flood control safety at the basin through forecasting flood elevation. Eventually, there are the flood risks from the River structure for Multi-functional Urban river as well as the river safety. As flood runoff analysis in urban, we need to consider risks which are drainage depth and other.

• Journal of Korea Water Resources Association
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• v.39 no.8 s.169
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• pp.677-690
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• 2006

The LH-OAT (Latin Hypercube One factor At a Time) method for sensitivity analysis and SCE-UA (Shuffled Complex Evolution at University of Arizona) optimization method were applied for the automatic calibration of SWAT model in Bocheong-cheon watershed. The LH-OAT method which combines the advantages of global and local sensitivity analysis effectively identified the sensitivity ranking for the parameters of SWAT model over feasible parameter space. Use of this information allows us to select the calibrated parameters for the automatic calibration process. The performance of the automatic calibration of SWAT model using SCE-UA method depends on the length of calibration period, the number of calibrated parameters, and the selection of statistical error criteria. The performance of SWAT model in terms of RMSE (Root Mean Square Error), NSEF (Nash-Sutcliffe Model Efficiency), RMAE (Relative Mean Absolute Error), and NMSE (Normalized Mean Square Error) becomes better as the calibration period and the number of parameters defined in the automatic calibration process increase. However, NAE (Normalized Average Error) and SDR (Standard Deviation Ratio) were not improved although the calibration period and the number of calibrated parameters are increased. The result suggests that there are complex interactions among the calibration data, the calibrated parameters, and the model error criteria and a need for further study to understand these complex interactions at various representative watersheds.

• Magazine of the Korean Society of Agricultural Engineers
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• v.39 no.2
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• pp.53-61
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• 1997

The interface system, GIS-AGNPS was to be validated with field data from six tested small watersheds ranging from 0.7 to 4.7$km^2$ in size which have steep topography and complex landuses. The model validation involved the calibration of input parameters and component modifications, in efforts to develop a model applicable to general uses for identifying and controlling nonpoint source pollution loads from agricultural watersheds. The simulated direct runoff from AGNPS was in good agreement with the field data for the averaged antecedent moisture conditions or AMC- II. The results differed, however, from the observed for AMC- I or III. A simple empirical relationship was proposed to estimate the curve number for AMC- I or m from AMC- II, which was found to result in simulated runoff close to the observed. The peak runoff relationship at AGNPS was also modified to reflect the watershed conditions and tested satisfactorily with the field data. The simulated sediment yields from the watersheds were fair as compared to the observed. Nutrient loads simulated from the model were different from the observed data. It appeared that the model was incapable of adequate depicting nutrient transport processes at paddy field and other landuses of the tested watersheds. Some modifications may be needed for the accurate representing the processes at paddy field.

• Korean Journal of Agricultural and Forest Meteorology
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• v.7 no.1
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• pp.4-14
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• 2005

CarboKorea and HydroKorea are the domestic projects aiming to improve our understanding of carbon and water cycles in a typical Korean forest located in a complex terrain with a watershed connected to large rivers. The ultimate goal is to provide a nowcasting of these cycles for the whole Peninsula. The basic strategy to achieve such goal is through the inter- and multi-disciplinary studies that synthesize the in-situ field observation, modeling and remote sensing technology. The challenge is the fact that natural ecosystems are nonlinear and heterogeneous with a wide range of spatio-temporal scales causing the variations of mass and energy exchanges from a leaf to landscape scales. Our paradigm now shifts from temporal variation at a point to spatial patterns and from spatial homogeneity to complexity of water and carbon at multiple scales. Yet, a large portion of our knowledge about land-atmosphere interactions has been established based on tower observations, indicating that the development of scaling logics holds the key to the success of CarboKorea and HydroKorea. Here, we review the pioneering work of FIFE (First ISLSCP Field Experiment) on scaling issues in a temperate grassland and discuss the lessons from it for the application to Gwangneung forest site.

• Journal of Environmental Science International
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• v.18 no.9
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• pp.1017-1026
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• 2009

In Jeju island, the surface runoff characteristics are quite different from those of inland. Most of streams show dried characteristics by means of large portion of recharge which goes to the deep aquifer. For this reason, the accurate estimation of hydrologic components by using watershed model like SWAT is very difficult. On the other hand, the integrated SWAT-MODFLOW model is able to simulate the complex runoff structure including stream-aquifer interaction, spatial-temporal groundwater recharge and so on. The comprehensive results of Pyoseon region in Jeju island show that the amount of groundwater discharge to stream is very small, but it might be added to the discharge into the sea. Statistical analysis shows that SWAT-MODFLOW's results represent better than SWAT's. Also, SWAT-MODFLOW produces a reasonable water budget which shows a quite similar pattern of observed one. This result proves that the integrated SWAT-MODFLOW can be used as a proper tool for hydrologic analysis of entire Jeju island.

• Journal of Korean Neurosurgical Society
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• v.44 no.3
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• pp.159-162
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• 2008

Stenting is a useful alternative treatment modality in carotid artery stenosis patients who are too high-risk to undergo carotid endarterectomy (CEA). We report a case of contralateral cerebral infarction after stenting for extracranial carotid stenosis. A 78-year-old woman was admitted to the hospital with left-sided weakness. Based on magnetic resonance imaging (MRI) of the brain and conventional angiography, she was diagnosed with an acute watershed infarct of the right hemisphere secondary to severe carotid stenosis. Stenting was performed for treatment of the right carotid artery stenosis after a one-week cerebral angiogram was completed. Thirty minutes after stent placement, the patient exhibited a generalized seizure. Four hours later, brain MRI revealed left hemispheric cerebral infarction. Complex aorta-like arch elongation, tortuosity, calcification, and acute angulation at the origin of the supra-aortic arteries may increase the risk of procedural complications. In our case, we suggest that difficult carotid artery catheterization, with aggressive maneuvering during stenting, likely injured the tortuous, atherosclerotic aortic arch, and led to infarction of the contralateral cerebral hemisphere by thromboemboli formed on the wall of the atherosclerotic aorta.

• Water for future
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• v.27 no.2
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• pp.139-146
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• 1994

Simplified sewer networks have been used to simulate runoff hydrographs for urban watersheds since configurations of sewer networks in urban area are commonly so complex that it is too cumbersome to simulate them as what they are. If they were to be simulated without any simplification, it is not likely that satisfactory results are obtained due to accumulation of numerous little errors. Even for the well-known models widely used in everyday practicesit is not appropriate to simulate everything in the watershed as what they are. In resolving these problems, it is common practice to simplify network configurations so as to be fitted to the models for runoff hydrograph simulation. In case of netwrok simplication, hydraulic and hydrologic characteristics of the watersheds should be carefully taken into consideration to derive meaningful results. On the bases of these considerations, this study analyzes simulation outputs using simplified networks and compares them, as well as inestigates the methods to make hydraulically sound simplification of sewer networks.

• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.4
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• pp.66-77
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• 2003

Monitoring data from agricultural reservoirs throughout the country were analyzed to classify agricultural reservoirs according to physical characteristics and COD concentrations, and evaluate the relationships bet-ween water quality items. The physical and chemical data of total 498 reservoirs were analyzed from 1990 to 2001. Average COD, TP, TN, Chl-a, SS concentrations for the reservoirs and pollutant loadings from their watersheds were used for the analysis. It was possible that reservoirs were classified to 4 types using the relationships between the ratios of effective storage per water surface (ST/WS ratio) and COD concentrations. It is recommended that the improvement measures of polluted reservoirs should be performed as following order : integrated consolidation type (complex mechanism type) $\rightarrow$ watershed consolidation type $\rightarrow$ integrated consolidation type (external mechanism type) $\rightarrow$ in-lake consolidation type $\rightarrow$ conservation type and the depth (ST/WS ratio) of reservoir maintained over 5~6 m for water quality improvement. The decision coefficients ($r^2$) between Chl-a and other items (COD, T-P, SS, T-N) were 0.6915, 0.6732, 0.5327, 0.3352, respectively. Therefore, reservoir managers could evaluate the trophic state of reservoirs by COD concentrations.