• Water Engineering Research
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• v.7 no.1
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• pp.1-8
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• 2006

Recently, the population growth and agricultural development are rapidly undergoing in the South-West Texas. The junction of three river basins such as Lavaca river basin, Colorado-Lavaca Coastal basin and Lavaca-Guadalupe Coastal basin, are interesting for non-point and point source pollutant modeling: Especially, the 2 basins are an intensively agricultural region (Colorado-Lavaca Coastal/Lavaca-Guadalupe Coastal basins) and several cities are rapidly extended. In case of the Lavaca river basin, there are many range land. Several habitat types wide-spread over three relatively larger basins and five wastewater discharge regions are located in there. There are different hazardous substances which have been released. Total nutrient loads are composed of land surface load and river load as Non-point source and discharge from wastewater facilities as point source. In 3 basins region, where point and non-point sources of poll Jtion may be a big concern, because increasing fertilizers and pesticides use and population cause. This project objective seeks to how to assess and control the accumulation of non-point and point source and discuss the main impacts of agriculture and environmental concern as non-point source with water quality related to pesticides, fertilizer, and nutrients and as point source with wasterwater discharge from cities. The GIS technique has been developed to aid in the point and non-point source analysis of impacts to natural resource within watershed. This project shows the losses in $kg/km^2/year$ of BOD (Biological Oxygen Demand), TN (Total Nitrogen) and TP (Total Phosphorus) in the runoff from the surface of 3 basins. In the next paper, sediment contamination will show how to evaluate in Estuarine habitats of these downstream.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.191-191
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• 2017

Floods have become more widespread and frequent among natural disasters and consisted significant losses of lives and properties worldwide. Flood's impacts are threatening socio-economic and people's lives in the Mekong River Basin every year. The objective of this study is to identify the flood hazard areas and inundation depth in the Mekong River Basin. A rainfall-runoff and flood inundation model is necessary to enhance understanding of characteristic of flooding. Rainfall-Runoff-Inundation (RRI) model, a two-dimensional model capable of simulating rainfall-runoff and flood inundation simultaneously, was applied in this study. HydoSHEDS Topographical data, APPRODITE precipitation, MODIS land use, and river cross section were used as input data for the simulation. The Shuffled Complex Evolution (SCE-UA) global optimization method was integrated with RRI model to calibrate the sensitive parameters. In the present study, we selected flood event in 2000 which was considered as 50-year return period flood in term of discharge volume of 500 km3. The simulated results were compared with observed discharge at the stations along the mainstream and inundation map produced by Dartmouth Flood Observatory and Landsat 7. The results indicated good agreement between observed and simulated discharge with NSE = 0.86 at Stung Treng Station. The model predicted inundation extent with success rate SR = 67.50% and modified success rate MSR = 74.53%. In conclusion, the RRI model was successfully used to simulate rainfall runoff and inundation processes in the large scale Mekong River Basin with a good performance. It is recommended to improve the quality of the input data in order to increase the accuracy of the simulation result.

• Korean Journal of Agricultural and Forest Meteorology
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• v.8 no.3
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• pp.174-182
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• 2006

This study was to clarify the effects of forest stand changes on hydrological components of evapotranspiration and discharge. The forest-hydrological experimental stations in Gwangneung and Yangju, Gyeonggido near metropolitan Seoul have been operated by the Korea Forest Research Institute since 1979 to clarify the effects of forest types and practices on the water resources and nutrient cycling and soil loss. The hydrological regime of the forested catchments may change as forests develop. The ranges of change may be different depending on forest types. Evapotranspiration can be estimated to 679mm, 580mm and 368mm in planted young coniferous (PYC), natural old-growth deciduous (NOD) and rehabilitated young mixed (RYM), respectively. The slope of the discharge-duration curve shows the capacity of discharge control in a specific catchment. The slope tended to be steeper in RYM than NOD, the better forest condition. The slope in RYM became more gentle as the forest stand developed. Forests can modulate peak flows through interception, evapotranspiration and soil storage opportunity. PYC and RYM showed 100 and 50mm of threshold rainfall for modulating peak flows, respectively. The deciduous forest did not represent sudden changes of peak flow rates to rainfall, even 200 mm rainfall Forest development in PYC may play an important role in modulation of peak flows because peak flow rates reduced after 10 years.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.2 no.1
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• pp.1-7
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• 1997

We have monitored nutrients, chlorophyll, suspended solids, and salinity in the Keum Estuary to understand the temporal fluctuation of oceanographic parameters and to illustrate any variation due to the gate operation of the Keum River Dike from June, 1995 to September, 1996, approximately for 500 days. Tidal range is used as the key factor to explain the fluctuations and atmospheric parameters such as air temperature, wind velocity and rainfall are also used supplementally. The fresh water discharge was selected as another major impact on the estuarine environment due to the gate operation of the Keum Dike. In addition, daily variation by tidal cycle was investigated twice in April and July, 1996. In diurnal variation, salinity was positively correlated with tidal elevation, whereas negatively correlated with nutrients. Relatively high suspended solid and chlorophyll contents were found in the period between high and low tide. In 500 days continuous observations, salinity was negatively correlated with the volume of fresh-water discharge, but positively correlated with nutrients. A major chlorophyll bloom occurred in spring. A similar pattern of variation was observed between suspended solid and the neap-spring tidal cycle. In comparison with the data of the Keurn Estuary before the gate operation of the Keum River dike, fresh-water discharge predominated other environmental factors during the rainy season. In addition, the velocity of tidal current and the concentration of suspended solid were decreased, while nutrients and chlorophyll contents were increased.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.3
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• pp.321-335
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• 2023

Monitoring sediment loads in natural rivers is the key process in river engineering, but it is costly and dangerous. In practice, suspended loads are directly measured, and total loads, which is a summation of suspended loads and bed loads, are estimated. This study proposes a real-time sediment discharge monitoring system using the horizontal acoustic Doppler current profiler (H-ADCP) and support vector regression (SVR). The proposed system is comprised of the SVR model for suspended sediment concentration (SVR-SSC) and for total loads (SVR-Q_TL), respectively. SVR-SSC estimates SSC and SVR-Q_TL mimics the modified Einstein procedure. The grid search with K-fold cross validation (Grid-CV) and the recursive feature elimination (RFE) were employed to determine SVR's hyperparameters and input variables. The two SVR models showed reasonable cross-validation scores (R²) with 0.885 (SVR-SSC) and 0.860 (SVR-Q_TL). During the time-series sediment load monitoring period, we successfully detected various sediment transport phenomena in natural streams, such as hysteresis loops and sensitive sediment fluctuations. The newly proposed sediment monitoring system depends only on the gauged features by H-ADCP without additional assumptions in hydraulic variables (e.g., friction slope and suspended sediment size distribution). This method can be applied to any ADCP-installed discharge monitoring station economically and is expected to enhance temporal resolution in sediment monitoring.

• Water for future
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• v.28 no.5
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• pp.151-162
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• 1995

A two-dimensional stream tube dispersion model is developed to simulate accurately transverse dispersion processes of pollutants in natural channels. Two distinct features of the stream tube dispersion model derived herein are that it employs the transverse cumulative discharge as an independent variable replacing the transverse distance and that it is developed in a natural coordinate system which follows the general direction of the channel flow. In the model studied, Eulerian-Lagrangian method is used to solve the stream tube dispersion equation. The stream tube dispersion equation is decoupled into two components by the operator-splitting approach; one is governing advection and the other is governing dispersion. The advection equation has been solved using the method of characteristics and the results are interpolated onto Eulerian grid on which the dispersion equation is solved by centered difference method. In solving the advection equation, cubic spline interpolating polynomials is used. In the present study, the results of the application of this model to a natural channel are compared with a steady-state flow measurements. Simulation results are in good accordance with measured data.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.45-50
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• 2006

About 50% of the population and 75% of the properties concentrate on the flood plain in Japan. The rivers have intimate relationship with our lives. Those conditions have been seen after modern river improvement projects that began about a century ago. The technology which was introduced from foreign countries was improved in conformity with geographical features and the climate condition of our nation, and has redeveloped as a Japanese original technology. In 1940's, Japan had serious natural disasters that were caused by large- scale typhoons. Those typhoons wiped out everything completely. Even though the government realized the importance of flood control and management after those natural disasters, civil work still aimed to economic development. Those construction works have become the one of factors for concentrating population and degrading natural environment in urban areas. Deterioration of river environment has become serious issue in urban development and main cause of pollution. The approaches for environmental restorations which were started about 30 years ago aimed to harmonize with nature environment and cities and human lives. There have been going on many projects called 'river environmental improvement projects', the 'nature friendly river works' and 'natural restoration projects.' The society has tried to find a way to live in harmony with nature. As for societies symbiotic with habitats will form the safe country in the history and the spectacle. Such as the symbiotic of the river or the basin where discharge, water quality, nature, the history, landscape, the local society and also for culture were built in is achieved. Examples of working, applied to restoration technologies and the one to describe the mechanism construction are been shown in the paper. Furthermore, write for an international spread of the river technology of Japan to attempt.

• Korean Journal of Pharmacognosy
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• v.39 no.3
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• pp.186-193
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• 2008

Astragali Radix, known as Huangqi, is the most important tonic in the traditional oriental medicine. It reinforces 'qi' (vital energy), strengthens the superficial resistance and promotes the discharge of pus and the growth of new tissue. It has long been used as an anti-perspirant, anti-diuretic or a tonic. Eleven compounds were isolated from the hexane and EtOAc fractions from the roots of Astragalus membranaceus (Leguminosae) and their structures were identified as four triterpenoids [lupenone (1), friedelin (2), lupeol (3), soyasapogenol E (9)] and seven sterols [${\beta}-sitosterol$ (4), stigmastane-3,6-dione (5), $7{\alpha}-hydroxysitosterol$ (6), $5{\alpha},6{\beta}-dihydroxysitosterol$ (7), $7-oxo-{\beta}-sitosterol$ (8), ${\beta}-sitosterol$ glucoside 6'-O-palmitate (10), ${\beta}-sitosterol$ glucoside (11)]. The chemical structures of these compounds were identified on the basis of spectroscopic methods and comparison with literature values. Among these compounds, lupenone (1), friedelin (2), lupeol (3), stigmastane-3,6-dione (5), $7{\alpha}-hydroxysitosterol$ (6), $5{\alpha},6{\beta}-dihydroxysitosterol$ (7), $7-oxo-{\beta}-sitosterol$ (8), soyasapogenol E (9), and ${\beta}-sitosterol$ glucoside 6'-O-palmitate (10) were isolated from this plant for the first time.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.2B
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• pp.139-147
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• 2012

This study is derived relationships of the resistance coefficients of Darcy-Weisbach and Manning for flow resistance and the dimensionless velocity using many field measurements for 1,875 rivers consist of sand 179, gravel 992, cobble 651 and boulder 53 channels in natural rivers, respectively. The relationships of power law forms are developed as a function of flow discharge, friction slope, and relative submergence by the regression and the semi-empirical method. The measurements distribution of Manning resistance coefficients by the Box-Whisker Plots show the values which ranges from 0.004~0.151 for sand, 0.008~0.250 for gravel, 0.015~0.327 for cobble, 0.023~0.444 for boulder in natural rivers, respectively. Relationships of these semi-empirical and resistance coefficients will be useful to give information in hydraulic engineering.

• Journal of Yeungnam Medical Science
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• v.8 no.2
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• pp.35-44
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• 1991

Recently many authors have reported about the relationship of the volumes of hemorrhage in the brain parenchyme, hemorrhagic sites, optimal operation time, and the effects of mannitol and steroid on control of ICP to clinical manifestations. Many attempts to measue ICP in hydrocephalus, brain tumor, and head injury have been reported. But the measurements of intracranial pressure in spontaneous intracerebral hemorrhage are rare. Intracranial pressure was monitored prospectively in 30 patients who had stereotaxic surgery for spontaneous intracerebral hemorrhage. The results are as follows. 1. Intracranial pressure was increased in high $PaCO_2$. 2. There were no correlation in ICP, rebleeding and ADL at discharge(P > 0.05). 3. ICP was the most high level in 72 hours after operation. 4. There was 63.2% decrease in ICP after litigation with 6000 IU urokinase in the site of hemorrhage. 5. There was no correlation between the numbers of natural drainage and ADL at discharge(P > 0.05). 6. The higher the initial GCS, the higher the Postoperative GCS.