• 보존과학연구
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• s.30
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• pp.103-124
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• 2009

Major and trace elements and cross section textures of the large-sized jar-coffins excavated in the Young San river area have been analyzed for categorization according to geochemical characteristics of the raw materials. As results, we have found out that the jar-coffins of the Oryang-dong and Ungok-dong have very similar characteristics, and those of Songwol-dong and Jangdeung show distinguishable characteristics from the others. In addition, similar characteristics have been detected in some U-shape jar-coffins from several sites such as Oryang-dong, Ungok-dong, Sinchon-ri, Mansu-ri and Yeon-ri posess on trace elements and cross section texture. These results indicate that there was active physical migration although the detail route of the physical migration is unclear at current stage.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.30 no.1
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• pp.67-73
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• 2012

Coastal erosion and its impact on human activities as well as the economic damage and environmental conservation of coastal area is one of major concern in the national policies. In this study, we conducted physical investigations to evaluate effects of erosion in the Geojin beach, which is located nearby the Geojin Port, for a detecting of shoreline change and beach cross-sectional area. The results showed that significant coastal erosion of the Geojin beach has occurred by the complex resources of natural factor, such as rising sea level, storm surges, high wave, and man-made construction. Especially, due to the sand supplement from Jasan river, the section which is nearby the estuary of Jasan river is maintained as a stable beach, whereas beach erosion of the other site in GW04 section has been increased indeed. Therefore, we suggest that it is need to continuous monitoring using DGPS and various surveying techniques to prevent beach erosion onto the GW04 section.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.52-59
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• 2005

The goal of this project is to estimate the instream flow of the Han River Basin to ensure the adequate supply of suitable quality water for preservation and enhancement of aquatic ecosystems. A applied model is Physical Habitant Simulation System(PHABSIM) of Instream Flow Incremental Methodology(IFIM). The parameters which are needed to simulation by PHABSIM such as flow depth, velocity distribution and channel cover with cross section data are obtained by field survey. The Habitat Suitability Criteria with the application of univariate curve on Zacco platypus as a target species was able to be established by conducting the field investigation. The estimated results of ecological recommended instream flow by this study has important meanings that the future river management have to seriously take into account for the natural environment and functions of river system.

• Korean Journal of Remote Sensing
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• v.34 no.2_1
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• pp.203-211
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• 2018

Dam discharge is carried out for the management of rivers and area around rivers due to rainy season or drought. Dam discharge should be based on an accurate understanding of the flow rate that can be accommodated in the river. Therefore, understanding the allowable storage capacity of river is an important factor in the management of the environment around the river. However, the methods using water level meters and images, which are currently used to determine the allowable flow rate of rivers, show limitations in terms of accuracy and efficiency. In order to solve these problems, this paper proposes a method to automatically calculate the allowable storage capacity of river based on the images taken by drone. In the first step, we create a 3D model of the river by using the drone images. This generation process consists of tiepoint extraction, image orientation, and image matching. In the second step, the allowable storage capacity is calculated by cross section analysis of the river using the generated river 3D model and the road and river layers in the target area. In this step, we determine the maximum water level of the river, extract the cross-sectional profile along the river, and use the 3D model to calculate the allowable storage capacity for the area. To prove our method, we used Bukhan river's data and as a result, the allowable storage volume was automatically extracted. It is expected that the proposed method will be useful for real - time management of rivers and surrounding areas and 3D models using drone.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.8 no.3
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• pp.61-71
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• 1988

The stage-discharge relation curve(rating curve) is the basic formula in hydrologic analysis. It plays an important role in converting to the discharge from available flood water level data including the daily mean stage. However, the river induces a cross section change at the gauging station because of the composed material of the river bed and three processes of the stream flow; i.e., erosion, transportation, and sedimentation. Rating curve has to be revised according to the temporal variation of the river bed due to the those factors. In this study, the basic rating curve is developed with respect to the current river bed to convert the existing rating curves and also to seize the hydraulic and geometric characteristics for the temporal variation of the river bed, relationships among the basic rating curve and the existing rating curves, water level, cross sectional area, and flow velocity are analyzed. Indogyo station, which is not only the key station of the Han river but also greatly changed the river bed after completion of the Han river development plan during the year 1983 to 1986, was chosen for the study. In this study, the river bed is assumed in a dynamic equilibrium condition. The basic rating curve is developed using hydrologic data of the physical year of 1987. For a given discharge, relationships for conversion of previous data, stage and velocity, the current one are formulated. To verify the usefulness of the relationships, stage-cross sectional area and stage velocity formula are also derived. Both hydrologic method using continuity equation and statistical method by the rating curve are compared and checked, then the validation of the both are positively shown.

• Magazine of the Korean Society of Agricultural Engineers
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• v.22 no.4
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• pp.96-107
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• 1980

This study is carried out to estimate the rate of sediment transportation both to measure the amount of suspended and bedload sediment that moves on or near the river bed and passes through the cross section of a river in unit time, with suspended and bed load samplers used for the Milyang river and to determine the most satisfactory and convenient formula of some formulas for sediment discharge by comparing the measured rate with the calculated rate. The results of this study are summarized as follows; 1) The interrelationship (1) between the total discharge and the total sediment discharge (2) between discharge and suspended sediment load and (3) between discharge and bed load in the Milyang river are (1) i) 4$\leq$Q$\leq$100 C.M.S. Qr=0. 00272 Q0.70 (kg/sec) ii) 150$\leq$Q$\leq$800 C.M.S. Qr=0. 4807 Q0.46 (kg/sec) (2) Qs~=0. 07576 Q1.02 (kg/sec) (3) QB=0. 00957 Q0.44 (kg/sec) 2) The rate of suspended sediment load to total sediment discharge is found to be about; 99%. The suspended load is shown to be almost wash load which consists of silt and clay. 3) The relation between the total discharge and the suspended sediment load that are measured at three medium and small rivers in Korea is Qs=0. 13831 Q0.97 (kg/sec) 4) Brown's formula is determined to be the most convenient formula for application and comparison with observed data obtained for the Milyang river.

• Journal of Korea Water Resources Association
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• v.54 no.3
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• pp.203-215
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• 2021

In the present study, hydrologic data and topographical data from 2010 to 2019 were collected from three gauging stations placed in the watershed of Naeseong stream to determine changes and rates of changes in rainfall, water level & mean velocity, and water level & discharge, together with changes in rates of erosion and deposition at cross-sections of the river. Besides, effects of regulated and non-regulated rivers according to the presence of artificial regulation of flow rate of the river via artificial structure located at Seo stream (Yeongju si (Wolhogyo) station), the tributary free from construction of dams, were compared and analyzed. Results of analyses conducted in the present study revealed vegetational establishment and landforming due to increasing area of vegetational sandbar evolved in the flood plain (intermediate- or high- water level) by the drought sustained from 2013 to 2015. Continuous erosion of river bed was appeared because of narrowed flow area with low water level and increased velocity and tractive force on river bed.

• Journal of Korea Water Resources Association
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• v.45 no.2
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• pp.127-136
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• 2012

River is able to change by various environmental factors. In order to conduct river restoration design, it is necessary to evaluate the stable channel through the analysis of past and present river channels. River evaluation requires various data, such as geometry, hydraulic and hydrology, but there is a lot of difficulty to understand topographical information of river change on time and space due to a lack of past data by domestic conditions. This study was analyzed abandoned channel formation, changes in the vertical-section and cross-section length of rivers, and micro-landform changes etc using an image analysis technique. Purpose of this research is to evaluates the stable channel through a river channel morphology change from past and present river channels image. Mangyoung river was conducted artificial river maintenance through straight channel consolidation form 1920 to 1930 year. In the result river maintenance, mangyoung river length was decreased by 15 km and abandoned channels of six points were made. Since then, weir was continuously increased to control bed slope and use water. Install of weir was to be the reason of changes on channel width, thalweg, vegetated bar, sand bar, water area. Present Mangyoung river show that water area was temporary increased in upper and middle reach because of weir installation. Total sand bar was only decreased in upper channel. The change of vegetated bar and sand bar was slight recently. In this result, Mangyoung river is inferred to reach stabilized channel although there is some difference to the lower reach.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.8 no.4
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• pp.305-313
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• 1996

CTD measurements were conducted in the Nakdong estuary on the several sections or along-plume and cross-plume directions in 1993 and 1994. Internal Froude number Fi=0.22-0.35 in ebb tides and 0.14 in flood tides suggest that Nakdong river plume may go farther seawards in the along-plume direction with little mixing with the adjacent sea water after the construction of Nakdong river barrier. From Dadae-Po to Gaduk-Do section of cross-plume direction, three cores of low salinity were found. The main plume outflows from the newly made channel by cutting Ulsuk-Do after the construction of barrier. The low salinity core found near Gaduk-Do is the plume patch advected by tidal currents. Rossby deformation radius varied with the tidal cycle so that Coriolis effect is strengthened in flood tides to deepen the isohalines westwards to the Gaduk-Do site. Internal wavelike shape was found in the section of cross-plume direction during ebb tides. Richardson number of the section suggests the possibility of forming internal wave but more precise observations are necessary.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.494-494
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• 2023

수치모형을 활용하여 하천 흐름을 해석하기 위해서는 하도의 형태를 나타내는 지형자료가 요구되며, 주흐름 방향에 직각 방향으로의 횡단면도는 다량의 자료가 필요하다. 측량을 통한 횡단면도의 확보는 시간과 비용이 많이 소요될 뿐 아니라 날씨와 같은 외부적 요인에 따라 측량 결과물의 정확도가 달라질 수 있다. 또한 하천의 유속이 매우 빠를 때에는 정확도 높은 횡단 측량자료를 얻기는 불가능하며 접근이 어려운 지역이나 중소규모의 하천 측량자료는 구축되어 있지 않은 실정이다. 이에 따라 위성영상과 수치표고모델(Digital Elevation Model, DEM)에 기반하여 하천구역과 하도의 특성을 정의하는 방법이 대안으로 제시되고 있다. 본 연구에서는 하천지형 측량자료가 존재하는 섬진강댐부터 오수천 합류전까지를 대상으로 가상하도 생성기법을 적용하고, 1차원 하천흐름해석을 수행하여 가상하도 구축방안의 유효성을 검토하고자 하였다. 위성영상 자료를 활용하여 하천구역을 정의하였으며 DEM에서 추출된 표고에 기반하여 제방고와 횡단면도를 구축하였다. 구축된 횡단면도와 실단면 비교시, DEM 표고 및 하천구역 정의 지점의 정확도에 따라 제방고가 달라지는 것으로 나타났으며, 홍수터에 대한 고려가 포함되지 않아 실단면과 다소 차이가 있는 것으로 확인된다. 구축한 지형자료를 1차원 하천흐름해석 모형인 K-River에 적용하였으며, 상류단 경계조건으로는 섬진강댐 방류량을 하류단 경계조건으로는 등류조건을 적용하였다. 구축영역 내 존재하는 지류의 유입량은 측방유입으로 고려하였다. 수치모의 결과로부터 구축된 횡단면의 최심고와 실단면의 최심고가 유사한 지점에서는 수위재현성이 양호한 것으로 확인되었다.