• 한국안전학회지
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• 제35권2호
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• pp.28-33
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• 2020

Recently, the overseas construction market has been actively promoted for about 10 years, and overseas dam construction has been continuously performed. For the economic and safe construction of the dam, it is important to prepare the main dam construction plan considering the design frequency of the diversion tunnel and the cofferdam. In this respect, the prediction of river level during the rainy season is significant. Since most of the overseas dam construction sites are located in areas with poor infrastructure, the most efficient and economic method to predict the water level in dam construction is to use the upstream water level. In this study, a linear regression model, which is one of the simplest statistical methods, was proposed and examined to predict the downstream level from the upstream level. The Pyeongchang River basin, which has the characteristics of the upper stream (mountain stream), was selected as the target site and the observed water level in Pyeongchang and Panwoon gaging station were used. A regression equation was developed using the water level data set from August 22th to 27th, 2017, and its applicability was tested using the water level data set from August 28th to September 1st, 2018. The dependent variable was selected as the "level difference between two stations," and the independent variable was selected as "the level of water level in Pyeongchang station two hours ago" and the "water level change rate in Pyeongchang station (m/hr)". In addition, the accuracy of the developed equation was checked by using the regression statistics of Root Mean Square Error (RMSE), Adjusted Coefficient of Determination (ACD), and Nach Sutcliffe efficiency Coefficient (NSEC). As a result, the statistical value of the linear regression model was very high, so the downstream water level prediction using the upstream water level was examined in a highly reliable way. In addition, the results of the application of the water level change rate (m/hr) to the regression equation show that although the increase of the statistical value is not large, it is effective to reduce the water level error in the rapid level rise section. Accordingly, this is a significant advantage in estimating the evacuation water level during main dam construction to secure safety in construction site.

• 한국수자원학회논문집
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• 제51권11호
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• pp.1011-1020
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• 2018

본 연구에서는 미급수지역의 주요 수원인 지하수위 현황을 이용한 가뭄 모니터링 기법을 개발하기 위해 256개의 국가지하수관측망 관측 자료를 이용하여 관측소별, 월별 수위분포를 핵밀도함수로 추정하였다. 추정된 누적분포함수를 이용하여 월별 지하수위의 분위수를 구하고, 분위수를 정규화 하여 표준지하수지수(SGI)를 산정하였다. 관측소별로 산정된 SGI는 티센망을 이용하여 167개 시군별 SGI로 변환하였다. SGI의 범위에 따른 가뭄등급을 설정하여 시군별 지하수 가뭄 정도를 모니터링 할 수 있는 기법을 제시하였다. 이를 통해 계측이 이루어지지 않는 미급수지역의 지하수가뭄상황을 국가지하수관측망을 활용해 간접적으로 판단할 수 있도록 하였다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2017년도 학술발표회
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• pp.188-188
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• 2017

Rainfall is an important input to hydrological models. The accuracy of hydrological studies for water resources and floods management depend primarily on the estimation of rainfall. Thailand is among the countries that have regularly affected by floods. Flood forecasting and warning are necessary to prevent or mitigate loss and damage. Merging near real time satellite-based precipitation estimation with relatively high spatial and temporal resolutions to ground gauged precipitation data could contribute to reducing uncertainty and increasing efficiency for flood forecasting application. This study tested the applicability of satellite-based rainfall for water resources management and flood forecasting. The objectives of the study are to assess uncertainty associated with satellite-based rainfall estimation, to perform bias correction for satellite-based rainfall products, and to evaluate the performance of the bias-corrected rainfall data for the prediction of flood events. This study was conducted using a case study of Thai catchments including the Chao Phraya, northeastern (Chi and Mun catchments), and the eastern catchments for the period of 2006-2015. Data used in the study included daily rainfall from ground gauges, telegauges, and near real time satellite-based rainfall products from TRMM, GSMaP and PERSIANN CCS. Uncertainty in satellite-based precipitation estimation was assessed using a set of indicators describing the capability to detect rainfall event and efficiency to capture rainfall pattern and amount. The results suggested that TRMM, GSMaP and PERSIANN CCS are potentially able to improve flood forecast especially after the process of bias correction. Recommendations for further study include extending the scope of the study from regional to national level, testing the model at finer spatial and temporal resolutions and assessing other bias correction methods.

• 한국해양공학회지
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• 제5권1호
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• pp.25-34
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• 1991

An accurate estimation of water level variation when thewaves propagate to the coastal regionis very important for the port and harbor development plan. This study describes the application of a hybrid element model to harbor oscillation problem due to the construction of shore structure and implementation of shore boundary. The site selected is Pusan Harbor area with the third development and the Artificial Island plan. The observed water level changes at the site are compared with the result of the numerical experiment. The model gives a very important prediction of water level changes for navigation and harbor design.

• KDI Journal of Economic Policy
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• 제44권4호
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• pp.1-24
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• 2022

We investigate how reforestation contributed to stabilization of riverine water levels in South Korea. For the purpose, we estimate an equation capturing dynamic relationships among rainfall, upstream-area tree stock, and downstream water levels in three river systems of Hongcheon, Mangyeong, and Hyeongsan, using daily observations of precipitation and water levels for the period from 1985 to 2005. Simulation based on estimation results shows that increase in the tree stock in a river basin leads to a significantly suppressed peaking in riverine water levels in response to an abrupt and concentrated rain in the upstream area. For instance, an hour-long concentration of 100mm rain results in 0.7m rise in water level if the volume of growing stock is 1 million m³, whereas the rise in water level stays below 0.27m with 5 million m³ in the growing-stock volume.

• 한국건설순환자원학회논문집
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• 제10권1호
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• pp.101-110
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• 2022

본 연구에서는 고주파가열법, 단위용적질량법, 정전용량법 및 마이크로파법의 4가지의 굳지 않은 콘크리트의 단위수량 시험방법의 신뢰성을 검토하기 위해 배합요인, 혼화재 치환율 및 골재의 물리적 특성 변화에 따른 다양한 콘크리트를 대상으로 단위수량 실험을 실시하고 시험방법별 단위수량 추정값의 오차를 분석하였다. 단위수량의 시험방법과 무관하게 추정오차는 5 % 이하의 수준을 나타냈으며, 모르타르를 이용하는 시험의 경우 상대적으로 추정값의 오차가 크게 나타났다. 다양한 배합의 콘크리트에 대한 단위수량 실험결과를 토대로 각 실험방법별 추정오차를 모집단으로 하는 확률밀도함수를 분석한 결과 모르타르 시료를 이용하는 단위수량 실험방법은 추정오차 ± 15 kg/m³ 내 97 %, 콘크리트 시료를 이용하는 단위수량 실험방법은 추정오차 ± 10 kg/m³ 내 97 % 이상의 신뢰성을 나타냈다. 향후 실제현장에서 다양한 생산변수를 고려하여 단위수량 실험방법의 신뢰성을 추가적으로 검증할 수 있는 연구가 필요할 것으로 판단된다.

• 한국농공학회논문집
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• 제63권1호
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• pp.27-35
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• 2021

KRC (Korea Rural Community Corporation) is in charge of about 3,400 agricultural reservoirs out of 17,240 agricultural reservoirs, and automatic water level gauges in reservoirs and canals were installed to collect reservoir and canal water level data from 2010. In this study, 10-minute water level data of 173 reservoir irrigation canals from 2016 to 2018 are collected, and discharge during irrigation season was calculated using rating curves. For estimation of water supply, irrigation water requirement was calculated with HOMWRS (Hydrological Operation Model for Water Resources System), and the summation of reservoir water storage decrease was calculated with daily reservoir storage data from RAWRIS (Rural Agricultural Water Resource Information System). From the results, the total yearly amount of irrigation water supply showed less than 10% difference than the irrigation water requirement. The regional analysis revealed that reservoirs in Jeollanam-do and Chungcheongnam-do supply greater irrigation water than average. On the contrary, reservoirs in Gyeongsangnam-do and Chungcheongbuk-do supply less than others. This study was conducted with a limited number of reservoirs compared to total agricultural reservoirs. Nevertheless, it can indicate irrigation water supply from agricultural reservoirs to provide information about agricultural water use for irrigation.

• 한국대기환경학회지
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• 제11권1호
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• pp.69-76
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• 1995

Water content and strong acidity are estimated for ambient particles measured between Fall, 1991 and Summer, 1992 in Seoul using a gas/aerosol equilibrium model, called SCAPE. Particle water content and formation of solid species are closely related to ambient relative humidity and ionic concentrations. Generally, water content of particles is high during the night and summer. Estimated particle strong acidity level of Seoul is similar to that of Los Angeles, U.S.A. Acidity of wet and dry depositions in Seoul is discussed.

• 자원ㆍ환경경제연구
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• 제18권1호
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• pp.105-138
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• 2009

본 연구는 한강의 수질측정망에서 관측된 오염물질별 연평균 오염도를 이용하여 지난 15년 동안 수질오염도의 공간적 분포에 유의한 변화가 발생하였는지를 분석하였다. 구체적으로 각 오염물질별의 비모수적 커널확률밀도함수를 추정하였고, 연도간 유의한 변화가 있는지 검정하였다. 또한 일반화된 엔트로피 계열의 불평등지수를 구하고, 부트스트래핑 기법을 통해 불평등지수의 차이가 유의한지를 검정하였으며, 순위 상관을 이용하여 오염도 순위의 동태적인 측면을 분석하였다. 분석결과 최근 15년 동안 수질오염도의 불균등 정도는 전반적으로 완화되거나 일정한 수준을 유지하였고, 오염도 순위에 동태적인 변화는 거의 일어나지 않은 것으로 나타났다.

• 한국수자원학회논문집
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• 제39권12호
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• pp.985-996
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• 2006

본 연구는 자갈하천에서 하상에 분포하는 입자에 작용하는 전단력을 이용하여 등가조도를 산정할 수 있는 모형을 개발하였다. 산정된 등가조도는 수위-유량자료가 부재한 하천에서 유량에 대한 수위를 산정하고 조도계수를 산정하는데 이용하였다. 대상하천은 섬진강의 중 하류부인 구례수위표와 송정수위표 구간으로 선정하였다. 등가조도는 개발된 모형에 의해 구례수위표지점에서 0.194m가 산정되었다. 산정된 등가조도를 흐름모형에 적용하여 계산된 수위유량자료를 관측된 자료와 비교한 결과 6% 이내의 오차를 보였다. 조도계수는 대상구간에 대해 부정류 해석을 실시하여 유량규모별로 계산된 수위와 관측된 수위에 대해 산정하였다. 그 결과 관측된 수위와 계산된 수위에 의해 산정된 조도계수는 $0{\sim}0.002$의 오차를 보였고, 조도계수의 가변성도 고려할 수 있었다.