• Journal of Korea Water Resources Association
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• v.40 no.12
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• pp.931-941
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• 2007

Traditionally, the decision of river width has aimed majorly at flood control and good river conveyance. And the river width has been decided by practitioner#s subjective and empirical opinion. Recently, however, there is a need for more objective and thus quantitative decision method for decision of river width considering not only economical aspect but also social or environmental aspect. This study adopts the analytic hierarchy process (AHP) to improve the objectiveness in the decision of river width. Criteria and a standardized process are presented for field application. Using the proposed method, one can prioritize various river width and make the optimal decision. We believe that the method can serve as a useful tool for river engineers in practice.

• Journal of Industrial Technology
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• v.27 no.B
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• pp.229-233
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• 2007

This research investigated the way of generating the flowing of water in case of artificial fluctuation of river width by the unidimensional numerical analysis in order to reconstruct vertical and expanse features of flowing, and the problem of existing numerical analysis in accordance with local enlargement and reduction of river through hydraulic model experiments with results of numerical analysis. The result revealed that when the local section change in the same river is exist, it showed 0.93m in the case of no change of local section in the hydraulic model experiments and numerical analysis, however, it presented 1.645m on the occasion of local section changes in the hydraulic model experiments and numerical analysis. In other words, there was a significant difference in the existing numerical analysis, when there was a local section change. As a result of the experimental section for the enlargement and reduction of local river width, due to the sensitive change for fluctuation of flood discharge, there was a significant difference between numerical analysis and hydraulic model experiments. In addition, the result of comparison between the enlargement and reduction of local river width confirmed that the result of numerical analysis with hydraulic model experiments showed larger generation of deviation in case of enlargement of section than in case of reduction of section.

• Korean Journal of Environmental Biology
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• v.39 no.1
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• pp.6-15
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• 2021

Various biometric and geometric measures were used to discriminate between the morphologically similar river puffer, Takifugu obscurus, tiger puffer, T. rubripes, their hybrids, and their triploid hybrids. The hybrids and triploid hybrids had greater anal fin width, nostril width, and snout length than the parental species (p<0.05). However, they had less caudal peduncle depth, inter-orbital width, head length, and head width(p<0.05). The morphometric and meristic characteristics of the hybrids and triploid hybrids were either intermediate between the parental species or more similar to those of one parental species. However, the external morphology of the hybrids and triploid hybrids was predominantly maternal. The triploid hybrids had asymmetry in the fin rays and gill raker numbers. This study identified phenotypic characteristics by distinguishing the morphological variables of river puffer, tiger puffer, their hybrids, and their triploid hybrids.

• Journal of Environmental Science International
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• v.22 no.2
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• pp.195-203
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• 2013

I investigated the river morphology and river naturality according to the environment of the Hwang River. The numbers of flexions at the upstream regions were more than those of downstream regions. The Hwang River showed very low overall diversity of the flow. Materials of river shore at low channel width were mainly boulders or gravel at the upstream regions, and the middle and downstream were silts and clay. Artificial masonry and natural materials were mixed from materials of river levees. The Hwang River was some of the natural herbaceous vegetation to riparian zones. Land utilities for floodplain were extremely overall farmland were predominant, and partly used by natural vegetation in the forest, a soccer field, some park facilities, residential, and commercial facilities. The water was width sleep / rivers beam ratio of 10 to 20%. Currently estimation for river naturality widely used in rivers were consisted of a narrow wide a variety of items and did not reflect the actual.

• Journal of Korea Water Resources Association
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• v.31 no.6
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• pp.675-684
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• 1998

This paper presents the empirical formulas for determining the design-width for medium rivers in the Han river basin. The design flood, the watershed ares, and the channel slope of 216 medium rivers in the Han river basin are collected. the design width formulas are then determined by 1) the least squares (LS) method, 2)the least median squares (LMS) method, and 3) the reweighted least squares method based on the LMS (RLS). The six types of formulas are considered to determine the acceptable type for medium streams in the Han river basin. The root mean squared errors (RMSE), the absolute mean (AME) errors, and the mean errors (ME) are computed to test the formulas derived by three regression methods. It si found that the equation related stream width to the watershed area and the channel slope is acceptable for determining the design width for medium streams in the Han river basin. It is expected that the equations proposed by this study be used an index for determining the design-width for medium streams in the Han river basin.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.728-733
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• 2002

The measurement of river discharge is among the most fundamental observations and is necessary for understanding many water-related issues, such as flooding hazards, sediment transportation, and nutrient movement. Traditionally river discharge is estimated by measuring the water stage and converting the measurement to discharge using a stage-discharge rating curve. The possibility of monitoring river discharge from satellites has been largely ignored, because it is difficult to measure water surface information from space with sufficient precision. In this paper, an efficient approach to discharge estimation using mainly satellite data is developed and described. The proposed method, which focuses on the measurement of water-surface width coupled with river width-stage and stage-discharge relationships, is applied to the Yangtze River with good results.

• Journal of Environmental Science International
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• v.20 no.10
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• pp.1309-1317
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• 2011

This study selected 6 river reach, which have various curved-channel, included in an object of study as making the Nakdong River, which is a real nature river, as a point of an object of study by using SMS RMA-2 model, a 2D numerical analysis model, and applied project flood and analyzed and examined characteristic of hydrological property and super-elevation, which includes characteristic of the velocity of a moving fluid. As a result, in a river reach, whose width is wide, angle of curved-channel has impact on the velocity of a moving fluid of inside of curved-channel and in a river reach, whose width is narrow, the radius of curvature and width of the river have impact on the velocity of a moving fluid of inside of curved-channel. Also it found out that the ratio of reduction in water-level of inside of curved-channel is more bigger than ratio of increasing in water-level of outside of curved-channel when project flood is increasing and angle of curve is increasing. Based on this, this study would be used as a expectation of danger and preliminary data in planning real river or a business, that creates an environment.

• Journal of the Korean Society of Hazard Mitigation
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• v.7 no.1 s.24
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• pp.47-56
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• 2007

The parameters are determined analyzing the hydraulic and hydrological characteristics of design floods, watershed, channel length, and river bed slope. The models are calibrated while the input hydrologic data are the field data of middle size areas in Guem river basin in Korea. The basic equations of design width are suggested by the multiple regression analysis and the results show excelled in comparisons as well as calibrations with the existing empirical formulas and the design criteria, respectively. The basic equations of design width in validation process is determined the regression functions with the design floods, watershed, channel length, river bed slope as the four parameters using other database in the same scales watershed. As a results, this study will be used for apply to determine of design width and river alignmentof the watershed in hydraulic fields.

• Journal of Korea Water Resources Association
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• v.48 no.3
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• pp.169-183
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• 2015

As a basic work for river restoration, analysis on fluvial geomorphological characteristics is made using past and present data to understand close-to-nature geomorphic status. The Miho and the Naesung Rivers are targets of this study. Fluvial geomorphic variables including valley-floor width, sinuosity, bankfull width, channel gradient, bed material size, bankfull discharge and unit stream power are evaluated with dominant processes. Though common sand-bed rivers with similar catchment area, the Miho and the Naesung Rivers are different in terms of valley-floor width, channel shape variables and dominant processes related with longitudinal location. In addition, analyses on interrelationship among the geomorphological variables are carried. Bankfull width is shown to be proportional to bankfull discharge, as is in a rough agreement with the previous studies. Relationship of bankfull discharge and channel gradient shows meandering and braiding are prevalent in the Miho River, whereas the most of the sub-reaches of the Naesung River fall to braiding. Relationship of channel gradient with width-depth ratio indicates dune-ripple processes are dominant in the Miho River, while the Naesung River shows longitudinal diversity from braiding in the downstream sub-reaches to riffle-pool and plane-bed along the upper ones. Analyses based on the past data on a river in a close-to-nature status are thought to be rather reasonable in comparison with those on the same river in a engineered condition.

• Journal of the Korean Institute of Landscape Architecture
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• v.35 no.1 s.120
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• pp.28-35
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• 2007

The purpose of this study is to evaluate the visual preference factors for river scenery, which can vary according to changes in water levels, to estimate the optimal ratio of water surface/river width. Five locations on the Youngsan and Sumjin Rivers were selected as representative samples and field survey data such as channel geometry with water levels were prepared to develop the slide of river scenery, To estimate the level of satisfaction in river scenery, slides of 4 different water levels at each of the representative locations were developed through questionnaire. To analyse the correlation between the visual preference for river scenery and preference factors, a multi regression analysis method was adopted in this study. According to the results of the multi regression analysis, Factor B(Aesthetic factors) have the greatest affect on visual preferences and Factor A(A Feeling of Open space and Physical factors) affect significantly to visual preferences for river scenery. The results of analysis shows that the most preferred W/B ratio varies from 0.5 to 0.7 and this result indicates that many people prefer high levels river flow to maintain a natural and harmonious view of rivers. The results of this study will contribute to the field of river landscape design and river restoration projects in order to maximize the human being's satisfaction as a part of nature.