• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.599-602
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• 2007

Flood damage has been increased due to abnormal climate and extreme rainfall. Especially, the increase of impervious areas and the decrease of flow travel times due to the urbanization have been caused heavy division of flood with the recent rainfall characteristics. In this study, hydrodynamics flow analysis has been needed two dimensional numerical analysis for correct stream flow interpretations on bridges as hydraulic structures in rivers. Therefore, comparative analysis has been accomplished by using HEC-RAS model and SMS-RMA2 model for one and two dimensional flow. Also, flood characteristics have been analyzed in urban stream basin.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.1306-1310
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• 2009

The roughness coefficients were estimated by the Manning's equation for the measured stage and flow velocity of Bocheong stream basin in Kum river. The relationships between the estimated roughness coefficients and the geomorphologic factors were formulated by the linear, logarithmic, exponential and power type function, thereafter correlation equations were presented. The correlation analysis was performed between the measured stream length and the basin area of Bocheong stream basin by the linear, logarithmic, exponential and power type function, and correlation equation for the stream length was given. The roughness coefficient has strong correlationship with stream slope, but low correlation coefficients with stream length and basin area. For the correlationship with the roughness coefficients and the stream slope, the logarithmic type function has the smallest correlation coefficient, on the other hand, the exponential type function has the largest correlation coefficient. For the relationship between the stream length and the basin area, the correlation coefficient of the logarithmic type function shows the smallest value, linear type function shows the largest value.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2003.10a
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• pp.67-70
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• 2003

This study is to trace the change of stream shape using the past series of aerial photographs and compare the land use changes of inland along the stream. For the Gyeong-an national stream, aerial photographs of 1966, 1981 and 2000 was selected and ortho photograph was made with RMSE of 1.25, 0.54, 0.72 pixels, respectively. As apparent changes of the stream, the consolidated reaches of stream with levee construction were straightened and their stream width widened. Especially the stream width of inlet part of Paldang lake was widened almost twice because of the rise of water level by dam construction in 1974.

• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.458-462
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• 2004

This study is to trace the change of stream shape using the past series of aerial photographs and compare the land use changes of inland along the stream. For the Gyeong-an national stream, aerial photographs of 1966, 1981 and 2000 was selected and ortho photograph was made with RMSE of 1.05, 0.54, 0.72 pixels, respectively. As apparent changes of the stream, the consolidated reaches of stream with levee construction were straightened and their stream width widened. Especially the stream width of inlet part of Paldang lake was widened almost twice because of the rise of water level by dam construction in 1974.

• Magazine of the Korean Society of Agricultural Engineers
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• v.23 no.1
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• pp.64-74
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• 1981

The stream morphological characteristics of watershed have important influence upon the analysis of runoff. In this study, the effect of the map scale on the stream morphological characteristics was used on the data taken from 15'(1:50, 000) and 7'30"(1 :25,000) topographic maps which could cover the whole Miho River basin This basin are the first tributary of the Geum. River. Otherwise, the longitudinal stream bed profile was calculated by Yang's theoretical stream bed profile, equilibrium profile and actual profile. In the result of this investigation the conclusion is that the resultant relationship obtained from different topographic maps in the scale on the same stream system has come upon the same result as the stream morphological characteristics. Therefore, the great amount of time and effort can be saved in studing the stream morphological charecteristics by using the 15' instead of the 7'30"map system excluding the first order streams.

• Journal of Energy Engineering
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• v.10 no.4
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• pp.299-309
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• 2001

This shell-and-tube heat exchanger design code based on stream analysis method was developed to design accurate and advanced heat exchangers. Several geometry factors which affect the heat exchanger design was explained. Stream analysis method to calculate flow fraction of each stream and heat exchanger design flow chart was introduced. Performance of developed simulation code was compared with Delaware09, Delaware10, DongHwa and ANL experimental data. The statistical results of performance evaluation indicated that most data points are predicted within $\pm$30%. But the pressure loss was over predicted.

• Journal of The Korean Society of Agricultural Engineers
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• v.61 no.4
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• pp.11-22
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• 2019

The objective of this study was to improve the cross-sectional area and height estimation method using stream width. Stream water levels should be calculated together to simulate inundation of agricultural land. However, cross-sectional survey data of small rural rivers are insufficient. The previous study has developed regression equations between the width and the cross-sectional area and between the width and the height of stream cross-section, but can not be applied to a wide range of stream widths. In this study, cross-sectional survey data of 6 streams (Doowol, Chungmi, Jiseok, Gam, Wonpyeong, and Bokha stream) were collected and divided into upstream, midstream and downstream considering the locations of cross-sections. The regression equations were estimated using the complete data. $R^2$ between the stream width and cross-sectional area was 0.96, and $R^2$ between width and height was 0.81. The regression equations were also estimated using divided data for upstream, midstream and downstream considering the locations of cross-sections. The range of $R^2$ between the stream width and cross-sectional area was 0.86 - 0.91, and the range of $R^2$ between width and height was 0.79 ? 0.92. As a result of estimating the cross-sections of 6 rivers using the regression equations, the regression equations considering the locations of cross-sections showed better performance both in the cross-sectional area and height estimation than the regression equations estimated using the complete data. Hydrologic Engineering Center - River Analysis System (HEC-RAS) was used to simulate the flood stage analysis of the estimated and the measured cross-sections for 50-year, 100-year, and 200-year frequency floods. As a result of flood stage analysis, the regression equations considering the locations of cross-sections also showed better performance than the regression equations estimated using the complete data. Future research would be needed to consider the factors affecting the cross-sectional shape such as river slope and average flow velocity. This study can be useful for inundation simulation of agricultural land adjacent to an unmeasured stream.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.3
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• pp.265-272
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• 2007

This study uses the SWAT model to analyze the characteristics of long-term runoff at the Ssang-cheon Basin located in the city of Sokcho, which is located in the province of Gangwon. The study considers the effect of snow packing and snow melting in a runoff simulation. In this simulation, the study examines the need to introduce a snow pack and snow melt model to evaluate the water resources of the mountainous region of the Gangwon province. The findings of this study indicate that the runoff hydrograph that was produced approximates the true measured flow when the effect of the snow pack and snow melt are considered, compared to when they are not factored in. The analysis of the flow duration curve indicates that the stream flow largely increases when the effect of the snow pack and snow melt are considered. The wet stream flow was shown to increase by nearly 3% due to the melting effect, while the normal stream flow, low stream flow and drought stream flow were shown to increase by slightly more than 10%. Specifically, it was found that as the stream flow decreases, the effect of the snow pack and snow melt on the stream flow increases.

• Journal of Korean Society of Rural Planning
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• v.5 no.1 s.9
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• pp.35-44
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• 1999

The purpose of this study is to find the bi-polar adjectives for rural stream landscape evaluation by the semantic differential scale and to suggest the major determinants of visual preference in rural stream landscapes. For this, the bi-polar adjectives for rural stream landscape evaluation was found by the method of the reliability test, and the spatial image was analyzed by the factor analysis. The level of visual preference was measured by slide simulation test, and these data were analyzed by the multiple regression. The major findings of this study can be summarized as follows : 1) Of the bi-polar adjectives expressing psychological and physical characteristics, the hi-polar adjectives which demonstrated reliability and consistency run as follows : Bi-polar adjectives expressing psychological characteristics : 'calm-bustling', 'unfamiliar-familiar', 'still-active','depressing-brisk', 'discomfortable-comfortable', 'suppressed-free', 'lifeless-living', 'quiet-noisy', 'unpleasant-pleasant'. Bi-polar adjectives expressing physical characteristics : 'artificial-natural', 'narrow-wide', 'rocky-not rocky', 'desolate-fertile', 'dirty-clean', 'enclosed-open', 'flat-steep', 'not gravelly-gravelly', 'thicketed-not thicketed', 'not weedy-weedy'. 2) Two factors, the harmony and the movement, were derived from the factor analysis for the psychological variables. Three factors, the naturalness, the rock, and the vegetation, were derived from the factor analysis for the physical variables. 3) Rural stream landscape types were classified into four types by the multi-dimensional scaling method. Type III, IV obtained higher rank of visual preference and type I, II obtained lower. 4) For all types, the factors determining the level of visual preference were found to be the harmony, the naturalness, and the vegetation. The visual preference determinants of rural stream landscape need to be considered in improving or restoring the rural stream landscapes.

• Journal of Korean Society on Water Environment
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• v.34 no.2
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• pp.164-172
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• 2018

This study aims to determine the community patterns of benthic macroinvertebrates and analyze the relationship between the communities and the water quality in the Pungyeongjeong Stream. We collected the samples four times by season. The number of species was 28 and the dominant species were Cheumatopsyche brevilineata, Hydropsyche kozhantschikovi, Baetis fuscatus, Chironomidae spp., and so on. The range of the dominant index was 0.54 to 0.93 and the mean was 0.77. The range of the diversity index was 0.94 to 2.54, and of the mean index it was 1.75. The ratio of filtering-collectors and clingers got lower, but the ratio of gathering-collectors and sprawlers got higher as collection progressed from the upper stream to the lower stream. The results of the Pearson correlation analysis showed COD, SS, TOC and total coliforms were highly related with biotic indices of benthic macroinvertebrates. The results of cluster analysis and non-metric multidimensional scaling ordination showed that the survey sites and periods were divided into three groups. The survey sites were divided into upper stream and middle-lower stream. The survey periods were divided into winter season and other seasons. Distribution of benthic macroinvertebrates showed some characteristics according to various influence factors; however long-term and regular investigations were thought to need analysis and prediction with various statistical methods.