• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.1219-1223
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• 2005

This study was accomplished to confirm the possibility of supplying stream minimum flow from detention storage which was determined to reduce peak flows of flood within developing planned district. The results analyzed was summarized as follows; Firstly, Sin-gil district situated in Ansan city was selected, of which watershed area has $0.56km^2$. And detention storage was determined to $5,370m^3$ from analyzing flood volume by the SCS unit hydrograph method. Secondly, using Visual Basic ver 6.0, a detention storage water balance model was developed, in which simulation was based on conditioning storage inflow and outflow according to streamflow volume or rate state. And streamflow was simulated using the DAWAST model. Thirdly, detention operation scenarios were consisted of the combinations with inflow referencing streamflow of 5mm/day, 10mm/day and outflow referencing streamflow of 1mm/day, 2mm/day. The developed detention storage water balance model was operated to simulate daily water storages of detention sized on flood by scenarios. Stream minimum flows were able to be supplied during 209 days to 237 days per a year, total volume of stream minimum flows supplied for this period was analyzed to reach 27 to $55\% of yearly streamflow volume. If inflow criteria of streamflows to detention was considered to be established on a theoretical condition, it is expected to supply stream minimum flows of 20 to $30\% of yearly streamflow from stream to detention. Also to maximize function of supplying urban stream minimum flow from detention storages, sewage waters within developing planned district have to be treated and entered to detention inflow together with streamflows to enrich function of detention planned to reduce flood volumes.

• Journal of the Korean Society of Marine Environment & Safety
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• v.13 no.4
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• pp.9-14
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• 2007

This study reviewed the behavior(movement) characteristics of floating marine debris flowing in the Nakdong River Estuary using a simple numerical particle-tracking model on the conditions of the maximum water discharge outflow from the Nakdong River barrage during the passage of typhoon Maemi in 2003. The simulation showed that the particle distribution and movement of floating marine debris in the Nakdong River Estuary reached a stable state at 72 hours after the typhoon had passed, during the flood period of river discharge. The quantity of floating particles distributed on the east coast of Gadeok and Jinu Islands increased by 40% at 33 hours after starting the model, while the change in other sea areas was 20-40%.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.3
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• pp.117-122
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• 2008

Generally, water is taken through channels and rivers, in which there are many weirs and structures, which cross rivers and temporally hold up water. But this way has its own shortcomings. It is main reason that the water flows through structures, and backwater come into being. So it causes many water quality problems and some flood side-effects and so on. In this study, among the various movable weirs, we installed bottom-discharged and air pressure movable weir in the experimental channel. And we analyzed flowing influence, which is followed by the angle variation of movable weir. We also make further study the flow characteristic variation followed by installing entrance at the bottom to discharge the bottom water. The analysis result was that installed weir angle was increased, and the discharge also gradually increased. The installed weir angle depended on the water quantity, which can be excluded in the bottom. In case of velocity, there was increased as maximum 21.9 times, according to there is entrance or not at the bottom. And in case of water level, it showed the water level of locally above the average decrease in the upper river of weir.

• Journal of Korea Water Resources Association
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• v.34 no.6
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• pp.627-640
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• 2001

Generally, the synthetic unit hydrograph method is presented to estimate the design flood in the ungaged watershed. However, due to the lack of rainfall-runoff data, the models developed in other countries such as U.S.A. and Japan have been widely used in Korea. Therefore, it may be essential to develope the rainfall-runoff model suitable for the hydrological char-acteristics in Korea. In this study, the representative unit hydrographs are derived from rainfall-runoff data at 19 basins in Selma-Cheon and 3-IHP experimental watersheds using ridge-regression method and Nash model. And a new synthetic unit hydrograph for Korea is suggested by integrating the described results and previous studies on unit hydrograph. The newly developed method is represented as two regression forms with three independent variables of watershed area, channel length, and channel slope by multiple regression analysis is carried out for each watershed, the coefficients of determination are not improved in all cases compared out for each watershed, the coefficients of determination are not improved n all cased the synthetic unit hydrograph for each watershed. Therefore, when the new method is applied to some watersheds, the result analyzed for all data has to be used.

• Journal of Environmental Science International
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• v.21 no.6
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• pp.739-747
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• 2012

Due to the difficulties for measuring flood discharge in the dangerous field conditions, conventional instruments with relatively low accuracy such as float still have been widely utilized for the field survey. It is also limited to use simple stage-discharge relationship for assessment of the flood discharge, since the stage-discharge relationship during the flood becomes complicated loop shape. In recent years, various non-intrusive velocity measurement techniques such as electromagnetic wave or surface images have been developed, which is quite adequate for the flood discharge measurements. However, these new non-intrusive techniques have little tested in the flood condition, though they promised efficiency and accuracy. Throughout the field observations, we evaluated the validity of these techniques by comparing discharge and velocity measurements acquired concurrently during the flood in a mountain stream. As a result, the flood discharge measurements between electromagnetic wave and surface image processing techniques showed high positive relationship, but velocities did not matched very well particularly for the high current speed more 3 m/s. Therefore, it should be noted here that special cares are required when the velocity measurements by those two different techniques are used, for instance, for the validation of the numerical models. In addition, authors assured that, for the more accurate flood discharge measurements, velocity observation as well as stage height is strongly necessary owing that the unsteady flow occurs during the flood.

• 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.

• Proceedings of KOSOMES biannual meeting
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• 2007.11a
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• pp.23-28
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• 2007

This study estimated the behavior(movement) characteristics of floating marine debris flowing in the Nakdong River Estuary using a simple numerical particle-tracking model. This numerical experiment considered the maximum water discharge outflow from the Nakdong River barrage during the passage of typhoon Maemi in 2003. The simulation showed that the particle distribution and movement of floating marine debris in the Nakdong River Estuary reached a stable state at 72 hours after the typhoon had passed, during the flαxl period of river discharge. The quantity of floating particles distributed on the east coast of Gadeok and Jinu Islands increased by 40% at 33 hours after starting the model, while the change in other sea areas was $20{\sim}40%$.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.243-243
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• 2011

수문조사를 우량, 수위, 유량을 측정하는 것으로 정의하고, 위와 같은 기록을 바탕으로 하면 우리나라의 근대 수문조사는 1911년에 시작된 것으로 볼 수 있다. 이에 따라 2011년은 우리나라의 근대 수문조사 100년이 되는 해이다. 이를 계기로 과거 우리나라 수문조사의 역사를 정리하고 새로운 발전방향을 제시하는 것이 필요하다. 본 연구에서는 1910∼1945년의 기간에 발간된 고문서를 대상으로 하여 수문조사에 대하여 작성한 문서를 발굴, 정리 및 분석하여 과거 수문조사에 대한 내용을 쉽게 파악하고, 역사적, 학술적으로 중요한 수문조사의 문서를 쉽게 접할 수 있도록 하였다. 1911년 이후에 수문조사, 하천, 기상, 수력, 홍수 등에 대하여 작성된 문서를 수집하기 위해서 문헌 조사를 실시하였다. 특히, 1911년부터 1940년의 일제 강점기때 조선총독부에서 우리나라의 수문조사 및 수자원 등에 대하여 발행한 문서 중에서 아직까지 일반인에게 보급되지 않은 문서를 중심으로 조사하였다. 이러한 문헌 조사는 국내외 도서관에서의 문서 검색, 고문서 판매서점의 판매문서 확인 등의 방법으로 이루어졌고, 이렇게 하여 수집된 문서는 총 115권이었다. 수집한 문서 중에서 조사 및 공사 연보, 원문 내용을 확인하기 곤란한 경우, 기번역된 문서를 제외한 나머지 문서에 대해서 내용을 쉽게 파악할 수 있도록 주요 내용을 정리하였다. 주요 내용에는 서지정보로서 저자, 발행기관, 발행연도, 핵심용어 등을 정리하고, 일본어로 작성된 문서 내용을 파악하는데 도움을 주기위해 주요 내용과 목차를 번역하여 정리하였다. 이렇게 정리된 문서는 본문 내용, 발행연도, 발행기관 등에 대하여 경향성을 살펴볼 수 있었다. 본문 내용에 대하여 살펴본 결과, 호우 등에 의한 수해 현황을 기술한 문서, 수문관측 자료를 기술한 문서, 하천조사 내용을 기술한 문서 등이 많은 것으로 나타났다. 발행연도별로 살펴보면, 1920년도와 1930년도에 많이 발행된 것으로부터 이 시기에 수문관측, 하천조사, 하천공사 등이 활발하게 이루어졌음을 짐작할 수 있었다. 그리고 이 문서들은 조선총독부에서 발행한 것으로 일본이 조선의 하천 상황을 파악하기 위해 계획적이고 체계적으로 수문관측, 하천조사 등을 실행하였음을 짐작할 수 있었다. 이와 같이 우리나라 수문조사의 역사를 발굴하고 분석한 결과 자료는 향후 우리나라 수문조사의 발전방향을 제시하는데 있어 밑거름이 될 수 있을 뿐만 아니라 학술적, 기술적으로 활용할 수 있을 것으로 판단된다.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.12
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• pp.1209-1217
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• 2008

For efficient turbid water management a SWAT model was established for the Imha-Andong watershed where serious turbid water problems have frequently occurred. To evaluate soil loss combined with rainfall runoff process, the analysis focused on comparing the daily runoff discharge and concentration of suspended sediment (SS) using measured data sets. The results of annual SS load analysis for each sub-basin using the calibrated model showed that in the entire target watershed the soil loss ranged from 0.7 to 5.9 tons/ha in year 2005 and from 3.0 to 34.0 tons/ha in year 2003 when the typhoon 'Maemi' severly affected the area. In the future, it is suggest to increase model simulation accuracies supported by a long-term and extensive monitoring to enhance basin-wide suspended sediment estimation and management.

• Water for future
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• v.9 no.1
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• pp.55-69
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• 1976

The purpose of this paper is to provide basic data for construction methods of leakage pretaction for estuary barrien which is constructed to in take restoration water from irigative use and a river flow in its ultimate dsicharge to ward to sea, The water, accordingly, has reviewed the discrepancis between theories and experiments based on the hydraulic analysis of ground water through a series of sourveys on equi-patential line of seepage flow and a series of some experiments. apparently, however, the research results herein might reflect in some part not more than inference since those experiments are not conducted in a real foundation but from an indoor experiment or calculation, conclusion in brief are itemized here-under. 1. small-scale barrier require cut-off wall, which should reach the complete impereable layer, 2. Duplication barrier is provided effective in protection saline water seepage. 3. a barrier with broad crest might enable protection of massive seepage by fresh water lens formed from precipitation.