• Journal of Korean Society on Water Environment
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• v.28 no.6
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• pp.833-842
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• 2012

In this study Window interface to Hydrological Simulation Program-FORTRAN (HSPF) developed by the United States Environmental Protection Agency (EPA) was applied to the upstream of Namgang watershed to estimate its applicability for estimating Delivery Ratio (DR) of water pollutants for Total Maximum Daily Load (TMDL). BASINS/HSPF which is selected in this study, is found to be appropriate for simulation of daily flow and water quality in target basins. DR was estimated utilizing discharge loads of unobserved sub-basin and delivery load of unobserved locations obtained not by actual evaluation but by simulation through validation and verification. Annual average DR of BOD, TN and TP were 0.97 ~ 1.50, 2.23 ~ 3.21, and 0.81 ~ 1.09 respectively. Net DR of dependent basins excluding influence of upstream basin was 1.50 ~ 1.70, 0.55 ~ 0.69, and 0.24 ~ 0.31, all of which are lower than those of independent basins area. Utilizing the model selected by this research, DR and Net DR of unobserved basins will be estimated, which will help determine priorities in management of basin areas.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.23 no.1
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• pp.13-17
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• 2012

An understanding of the history of laryngology is both interesting and useful for those in the field so this study attempts to uncover some of the interesting aspects of its history. The oldest reference of laryngology in the Orient is in the medical documents called the "Whangjainaekyung",(황제내경) which was written over a time period between 3000-4000 B.C., and described the laryngeal function of respiration, protection of the airway and phonation. In the West, a drawing that seems to portray a tracheostomy was found in medical tombs in the plains of Saqqara in Egypt. These drawings date from approximately 3600 B.C. A watershed in laryngology occurred when a spanish music professor named Manuel Garcia in first successfully used a mirror to inspect the larynx. Since that time, laryngology has developed relatively quickly and clinical laryngology made it possible by means of a number of favorable developments. Great advances in laryngological diagnosis and treatment has occurred since the 1970s thanks to improvements in technology leading to the introduction of an operating microscope, endoscopes and lasers. Despite our recent advances in laryngology, we still have not achieved uniformly favorable outcomes and there is much that we do not know. Our future promises continued advances in the field of laryngology such as gene therapy to improve wound healing and tissue engineering to allow the recreation of normal mucosa. In this review, I divide the history of the larynx into the past, present and future. In the last section, I described the history of laryngology in Korea briefly.

• Smart Structures and Systems
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• v.26 no.6
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• pp.781-796
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• 2020

Prediction of total sediment load is essential in an extensive range of problems such as the design of the dead volume of dams, design of stable channels, sediment transport in the rivers, calculation of bridge piers degradation, prediction of sand and gravel mining effects on river-bed equilibrium, determination of the environmental impacts and dredging necessities. This paper is aimed to investigate and predict the total sediment load of the Wadi Arbaat in Eastern Sudan. The study was estimated the sediment load by separate total sediment load into bedload and Suspended Load (SL), independently. Although the sediment records are not sufficient to construct the discharge-sediment yield relationship and Sediment Rating Curve (SRC), the total sediment loads were predicted based on the discharge and Suspended Sediment Concentration (SSC). The turbidity data NTU in water quality has been used for prediction of the SSC in the estimation of suspended Sediment Yield (SY) transport of Wadi Arbaat. The sediment curves can be used for the estimation of the suspended SYs from the watershed area. The amount of information available for Khor Arbaat case study on sediment is poor data. However, the total sediment load is essential for the optimal control of the sediment transport on Khor Arbaat sediment and the protection of the dams on the upper gate area. The results show that the proposed model is found to be considered adequate to predict the total sediment load.

• Journal of the Korean Institute of Landscape Architecture
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• v.39 no.2
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• pp.103-112
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• 2011

The purpose of this study is to specify the prior eco-preserve zone by establishing the eco-landscape unit on the stream corridor and evaluating the stream ecosystem in the dam basin. The fundamental ecological data was surveyed and collected through "the ecosystem project on Yongdam multipurpose dam watershed" from 2008 to 2009. The Yongdam Dam Watershed has several streams, Jujacheon, Jeongjacheon and Guryangcheon, of which the area is $930km^2$, stretching to Jinangun, Jangsugun and Mujugun Jellabukdo. In spite of being used for drinking purpose, the dam water quality and ecosystem is threatened by in-watershed pollution produced by development, golf course grounds and sports complex, etc. The landscape unit of stream corridor was zoned across by 250m, 500m, and 750m from the vicinity line of stream, which was decided to the accuracy of mapping and surveying. Types of evaluation are the Stream Corridor Evaluation(SCE) and the Vegetated Area Evaluation(VAE). In the process of SCE, several indices were analysed, fish species diversity, species peculiarity, and stream naturality. Indices for VAE were forest stand map, vegetation protection grade, species diversity and peculiarity for wild bird and mammal life. The importance of the ecological items is categorized into three levels and overlapped for specifying the prior preserve zone. The area at which legally protecting species appeared is categorized as absolute preserve area. This study might be meaningful for proposing the evaluation process of a stream corridor ecosystem, which can synthesize a lot of individual ecological surveys. We hope further research will be actively performed about the ecotope mapping which is based on a individual wildlife territory and habitats and also their relationships.

• Journal of Environmental Science International
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• v.27 no.6
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• pp.411-423
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• 2018

To investigate the distribution characteristics of grain size and organic matter of surface sediments from the Nakdong-Goryeong Mid-watershed, surface sediments were collected and analyzed. The samples were collected from six sited at four different times between May 2013 and May 2014. The were analyzed for grain size, water content, ignition loss, chemical oxygen demand, total organic carbon and total nitrogen. The surface sediments were mainly composed of medium sand (mean 44.7%) and coarse sand (mean 32.8%) and became coarser in May 2014. Fine sediments at the site NG-2 were poorly sorted and positively skewed, and occur in a tributary environment that is relatively low-energy compared with the other sites. The water content at the studied sites (15.3 ~ 34.9%) averaged 20.25%, and ignition loss (0.4 ~ 5.8%) and total nitrogen (274 ~ 2493 mg/kg) averaged 1.33% and, 696 mg/kg, respectively. These values indicated that the sediments were not seriously contaminated when compared with the sediment pollution evaluation standard of the National Institute of Environmental Research. The chemical oxygen demand (mean 0.17%) was at the non-polluted level compared with United States Environmental Protection Agency sediment quality standards. The total organic carbon (mean 0.18%) at all sites except site NG-2 (lowest effect level) was the no effect level of the Ontario sediment quality guidelines. The COD/IL (0.02 ~ 0.20) and C/N (0.73 ~ 6.76) were less than 1 and 10, respectively. Organic matter in the study area produced naturally from aquatic organisms. Results of principal component analysis showed that fine sediments (very fine sand and silt) were significantly affected by organic matters (ignition loss, chemical oxygen demand, total organic carbon and total nitrogen). In addition, the highest organic matters content in the study area occurred at the site with the finest sediments (NG-2).

• Journal of Korea Water Resources Association
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• v.46 no.1
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• pp.35-45
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• 2013

The aim of study is to present how to estimate and use the FRI (Flood Risk Index) for classifying area zones based on regional flooding risk in terms of the integrated flood risk management. To estimate the FRI at a spatial resolution of city/county/town units for the Nakdong River Watershed, the 17 representative flood indexing factors are carefully selected for the three flood indexes, such as PI (Pressure Index), SI (State Index), and RI (Response Index) under the P-S-R (Pressure-State-Response) classification system. Because flood indexing factors are measured at different scales and units, they are transformed into a common domain by the T-Score normalization technique. The entropy weight coefficient method is also applied to calculate the weight of flood indexing factors in order to reduce subjective judgement on the effect of weight coefficients. The three flood indexes of PI, SI, and RI are integrated for an overall value of the FRI to evaluate the flood risk of districts. To examine the practical application of the proposed FRI, the FRI results with/without the weight coefficients are compared with flooding zones of natural disaster risk areas officially announced in 2010. It is expected that the FRI ensured by full verification can make regional protection plans against flooding disasters with respect to causes and characteristics of past floods.

• Journal of Korean Society of Disaster and Security
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• v.14 no.4
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• pp.9-15
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• 2021

The frequency of flash floods in mountainous areas is increasing due to the abnormal weather that occurs increasingly in the recent, and it causes human and material damages is increasing. Various plans for disaster mitigation have been established, but artificial plans such as raising embankment and dredging operation are inappropriate for valleys and rivers in national parks that prioritize nature protection. In this study, flood risk assessment was conducted for Gyeryongsan National Park in Korea using the WMS (Watershed Modeling System)which is rainfall runoff model for valleys and rivers in the catchment. As the result, it was simulated that it is flooding in three sub-catchments (Jusukgol, Sutonggol, Dinghaksa) of a total in Gyeryongsan National Park when rainfall over the 50 years return period occurs, and it was confirmed that the risk of trails and facilities what visitors are using was high. The risk of trails in national parks was quantitatively presented through the results of this study, and we intend to present the safe management guidelines of national parks in the future.

• Journal of Korea Water Resources Association
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• v.30 no.6
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• pp.691-698
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• 1997

The risk assessment model for dam and levee is applied to a river where two adjacent dams are located in the upstream of the watershed. "A" dam is proven to be safe with 200-year precipitation and unsafe with PMP condition, whereas "B" dam to be safe with 200-year precipitation and PMP condition. The computed risk considering the uncertainties of the runoff coefficient. initial water depth and relevant data of the dam and spillway turn out to be equivalent results in Monte-Carlo and AFOSM method. In levee risk model, this study addresses the uncertainty of water surface elevation by Manning's equation. Monte-Carlo simulation with the variations of Manning's roughness coefficient is calculated by assuming that it follows atriangular distribution. The model can be used for preparing flood risk maps, flood warning systems, and establishing nation's flood disaster protection plan.

• Water Engineering Research
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• v.6 no.2
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• pp.39-48
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• 2005

The Brazos River is one of the longest rivers contained entirely in the state of Texas, flowing over 700 miles from northwest Texas to the Gulf of Mexico. Today, the Brazos River Authority and Texas Commission on Environmental Quality interest in drought protection plan, waterpower project, and allowing the appropriation of water system-wide and water right within the Brazos River Basin to meet water needs of customers like farmers and local civilians in the future. Especially, this purpose of this paper primarily intended to provide the data for the engineering guidelines and make easily geological mapping tool. In the Brazos River basin, many stream-flow gage station sites are not working, and they can not provide stream-flow data sets enough for development of the Probable Maximum Flood (PMF) for use in the evaluation of proposed and existing dams and other impounding structures. Integrated GIS-Spatial Interpolation (GIS-SI) tool are composed of two parts; (1) extended GIS technique (new making interface for hydrological regionalization parameters plus classical GIS mapping skills), (2) Spatial Interpolation technique using weighting factors from kriging method. They are obtained from the relationship among location and elevation of geological watershed and existing stream-flow datasets. GIS-SI technique is easily used to compute parameters which get drainage areas, mean daily/monthly/annual precipitation, and weighted values. Also, they are independent variables of multiple linear regressions for simulation at un gaged stream-flow sites. In this study, GIS-SI technique is applied to the Brazos river basin in Texas. By assuming the ungaged flow at the sites of Palo Pinto, Bryan and Needville, the simulated daily/monthly/annual time series are compared with observed time series. The simulated daily/monthly/annual time series are highly correlated with and well fitted to the observed times series.

• Journal of Wetlands Research
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• v.12 no.3
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• pp.39-47
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• 2010

Annually, the scale of agricultural areas in Korea were being reduced as the lands were converted to other land uses. While the rate of productivity were either being maintained or increased, the pollution load from these areas were still greater in magnitude. Although the levels of pollutant concentration released in the agricultural watersheds were minimal, the combined quantities mostly from diffuse sources were high. As a consequence, the Ministry of Environment (MOE) in Korea adopted the use of free water surface (FWS) flow constructed wetlands to reduce the pollutant loadings emitted from agricultural watersheds for the improvement of water quality and protection of aquatic ecosystems. In this study, a constructed wetland treating stream water in an agricultural watershed was monitored since April 2009 subsequent to its completion in December 2008. Satisfactory performance was achieved for TSS, BOD and TP with 26%, 28% and 39% pollutant removal rates, respectively. In addition, the effluent water quality was improved and achieved compliance the national water quality criteria. Results of this study can be useful to establish design parameters and employ proper removal techniques of similar natural treatment systems for future implementation in the country.