• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.612-615
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• 2007

The environmental damage caused by river-improvement and slope of incision cliff can dest habitations of animate nature and it takes long time for restoration. River system constructed with stability of flood control, fine biotope, harmony with surroundings should be need to protect and restore nature. Therefore, in this study, conduct comparative experiment in various methods which are stable hydraulically and develop vegetation on revetment of bank, stream bed protection and disaster prevention aspect.

• Water for future
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• v.13 no.2
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• pp.49-54
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• 1980

Meandering has been attributed to the earth's rotation, to the excessive slope and energy of a river, to changes in stage, etc. The purpose of this study is a geometrical approach of meander shape and to derive the relationship among meander characteristics. In the analysis of sime field examples, in spite of variety of meander shapes, the sine-generated curve was fit actual quite well and better than alternatives against the channel distance. An attempt is made to find considerable relation among meander characteristics. But width and meanderbelt did not show any defined trend considerable scatter of points was observed.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.09a
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• pp.351-352
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• 2005

• Journal of Korea Water Resources Association
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• v.51 no.8
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• pp.687-701
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• 2018

A multi-function weir is representative control structure in the stream flow. Estimation of accurate flood discharge according to gate operations and prediction of floodwave travel times at the downstream are very important in terms of water use and river management. This study analyzed the limitation and improvement through the current gate operation data on the Young-san river. in addition, flood discharge was calculated considering lower and upper water level condition and gate operating using the modified slope-area method in the Seoung-chon weir. As a result, the current state was required improvement because exceed the theoretical range and rapidly fluctuation of discharge coefficient, can not be considered difference between the upper and lower water level and the estimation by the regression equation. As a result of applying the proposed method in this study, the above mentioned limitations can be compensated, compared with the current discharge data. Also it was analyzed as more physically valid because using the evaluated hydraulic equation and estimate the slope and friction loss of natural stream by iteration and to reduce the error. In conclusion, the process carried out serves as a representative flow control point of the water system through reliable discharge estimation, it is expected that it will be possible to properly river management.

• Ecology and Resilient Infrastructure
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• v.2 no.2
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• pp.118-127
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• 2015

Because streams have a great diversity of morphological features according to their reaches, it is necessary to classify the types of streams in order to assess their characteristics of channel. In addition, a quantitative assessment system for channel characteristics should be reflected in the stream type properties. Therefore, this study compares two stream classification system (Rosgen's and Yamamoto's) to review their applicability on Korean streams, and the two classification systems were applied on the Nam River. In order for the mean bed slope and the longitudinal connectivity of the provincial and national streams to be reflected in the assessment system of channel characteristics, the Yamamoto system is considered highly adaptable in the stream geomorphology side. In addition, it has been found the Rosgen system has a low correlation of bed slope compared to the Yamamoto system in the view of bed materials. On the other hand, the Yamamoto system was found to be capable of reflecting sediment sorting (hydraulic sorting) of the bed slope. According to the results obtained at the Nam River, the Rosgen system could not classify a type of stream by relationship between bed material and bed slope, but the Yamamoto system can verify the correlation of stream type. However, further review is needed with respect to the applicability of natural rivers. Three types of stream that can be applied to the assessment system of channel characteristics were proposed.

• Korean Journal of Remote Sensing
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• v.12 no.2
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• pp.169-198
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• 1996

The objectives of this investigation are : 1. To analyze spectral signature and the associated vegetation index for geometric illumination conditions inf1uenced by low solar elevation and high slope orientations in mountainous forest. 2. To assess the accuracy of the spectral angle mapper classification for the a winter land cover in comparison with the maximum likelihood classification. 3. To produce the image of water quality and water properties that could be used to estimate the water pollution sources and the tide-included by turbid water in estuarine and coastal areas. These objectives are to characterize environmental and ecological monitoring applications of the Nak-Dong River Basin by using Fuyo-1 OPS VNIR data acquired on December 26, 1992. The results of this paper are as follows : 1. The spectral digital numbers and vegetation indexes (NDVI and TVI) of mountainous forest are higher on the slope facing the sun than on the slope hidden the sun under low sun elevation condition. 2. The spectral angle mapper algorithm produces a more accurate land cover classification of areas with steep slope, various aspects and low solar elevation than the maximum likelihood classifier. 3. The maximum likelihood classification images can be used for identifying the location and movement of both freshwater and salt water, regardless of geometric illumination conditions. 4. The color-coded density sliced image of selected water bodies by using the near-infrared band 3 can provide distribution of the water quality of the Lower Nak-Dong River. 5. The color-coded normalized difference vegetation index image of the selected mountain forest is suitable to classify winter vegetation cover types, i.e., forest canopy densities for slope orientations.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.26-26
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• 2012

The Kurobe river, which runs through eastern Toyama Prefecture is one of the most famous rivers for wild water because of its steep slope in the range from 1/5 to 1/120. This river forms an alluvial fan in the range up to 13 kilometers from the sea. In this region, significant seepage flow occurs and thus the stream sometimes been intermitted. Moreover, the amount of seepage flow seems to vary with the groundwater level of the region. To keep the river environment healthy for flora and fauna, especially to conserve good condition for spawning of fishes, an appropriate environmental flow should be maintained in the river. To achieve this target, controlling of the upstream reservoir has to be studied in depth. One of the major problems to decide the amount of water to be released from the reservoir to maintain the environmental flow is to estimate the amount of water leaked into the groundwater from the river. This phenomenon is affected by the river flow rate as well as the groundwater level in the alluvial fan and the conditions vary in space and time. Thus, a grid-based hydrological cycle analysis model NK-GHM has been applied to clarify the hydrological cycle componentsin this area including seepage/discharge from/to the river. The model was tested by comparing with river flow rate, groundwater levels and other observations and found that the model described those observations well. Consequently, the seepage from the Kurobe river was found significant but it was also found that the groundwater in this region has been preserved by the recharge from the irrigation water supply into paddy fields in the alluvial fan.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.1B
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• pp.57-62
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• 2011

The river disaster caused by installation of hydraulic structures on the river gives varieties to flowing water stream, tractive force and so on. In this study, the changes of tractive force and energy from the side weir installation for the purpose of flood control was analyzed through laboratory experiment. The experiments of the pre and after-installation have been performed under conditions that waterway is trapezoidal shape, waterway slope ranges are from 0.1 to 1.0 percentage, and flow rates are 25 l/sec. As results, the specific energy ratio increases in the higher slope and at a certain point, larger specific energy ratio showed than 1 in the 1.0% slope. The tractive force ratio decreases in higher slope and the sections that tractive force ratio appeared higher than 1 are more widespread in the direction of downstream. And calculated tractive force is about 1.3.

• Journal of Korea Water Resources Association
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• v.44 no.3
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• pp.179-188
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• 2011

In this study, the regional factors in Gangwondo were used to analysis the relationship between point precipitation and areal precipitation. The most province area in Gangwondo is consist of mountainous terrain. At the east part of the Taebaek Mountains, the slope is very steep and the coastal plains don't exist. At the west part of the Taebaek Mountains, the slope is mild, there are many rivers, such as South Han-river and North Han-river, and the regions are very complex terrain. The data of 66 stations in Gangwondo and the PRISM (Parameter-elevation Regression on Indepedent Slope Model) were used to estimate the spatial distribution of precipitation. According to the topographic conditions, such as elevation and slope, and the regional conditions, such as Youngdong and Youngseo, the spatial distribution of precipitation is well shown. At the results of cross-validation, the RRBIAS and the RRMSE are under 0.1 and therefore the analysis of the PRISM are well conducted. Consequently the PRISM in this study is a appropriate method to estimate the spatial distribution of precipitation in Gangwondo.

• Journal of Korea Water Resources Association
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• v.34 no.4
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• pp.365-379
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• 2001

This paper presents an echo-hydraulic experimental approach to assessment of ascending capacity of migratory fish in a baffled fishway. Sweetfish, Plecoglossus altivelis, trout, Oncorhynchus mykiss, are used in these experiments. Ascending environment of the migratory fish in rivers is analyzed through the results of taco-hydraulic experiments. Important factors affecting the ascending capacity of migratory fish in baffled fishways are the discharge and slope of fishways and the fall height between the fishway entrance and the river bed. In these fishways the migratory capacity of sweetfish for a given fishway discharge is mainly affected by fishway slope, whereas the ascending capacity of trout for a given fishway slope was influenced by the change of fishway discharge. Loss of ascending properties of landlocked salmon, Oncorhynchus masou var ishikawai, was confirmed by these experiments. An ascending hydraulic criteria of the baffled fishway is defined by means of dimensionless factor F$_{f}$ and falling head H$_{f}$. Ascending capacity of migratory fish in existing baffled fishways in river of eastern coastal region is poor because the slope of fishways is verb steep.eep.