• Journal of Korea Water Resources Association
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• v.52 no.12
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• pp.975-984
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• 2019

As an essential prerequisite for systematic and integrated management of river water, it is necessary to secure the basic data such as discharge supplied to the river and released from the river. Under the current permit system for river water use, 59.1% of licensed facilities were found to have no discharge meters in 2017, especially for agricultural water, which makes it difficult to secure reliable data as a large portion of the reports are voluntarily reported by users. In this study, the indirect discharge measurement method of calculating the discharge through the power usage of the pumping station was applied to secure reliable discharge data. In particular, focusing on the fact that the discharge calculated by the power usage method differed with the actual discharge according to the level of the river, the study was conducted on improving the power usage method reflecting the river water level and improving the accuracy of discharge data. Analysis of the discharge calculated using the power usage method considering river water level using the correlation analysis method such as regression analysis, percent difference, root mean square error etc. confirmed that the results are not high compared to the conventional power usage method, but are slightly more approximated to the actual discharge. Therefore, although reliable discharge data can be obtained from the existing power usage method, it is expected that more accurate data on intaking water of river water can be obtained if the improved power usage method is used at points where the variation in the water level of the river is large.

• Journal of Korea Water Resources Association
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• v.38 no.7 s.156
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• pp.537-544
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• 2005

For the proper management of high pressurized gas storage caverns, analysis of groundwater flow field and inflow quantity according to the groundwater head, gas storage pressure and water curtain head should be performed. The finite element method has been widely used for the groundwater flow analysis surrounding underground storage cavern because it can reflect the exact shape of cavern. But the various simulations according to the change of design factors such as the width of water curtain, shape of cavern etc. are not easy when elements were set up. To overcome these limitations, two dimensional groundwater flow model is established based on the boundary element method which compute the unknown variable by using only the boundary shape and condition. For the exact computation of drainage rate into cavern, the model test is performed by using the exact solution and pre-developed finite element model. The test result shows that the model could be used as an alternative to finite element model when various flow simulations are needed to determine the optimizing cavern shape and arrangement of water curtain holes and so forth.

• Magazine of the Korean Society of Agricultural Engineers
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• v.14 no.3
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• pp.2741-2748
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• 1972

With 31 existing reservoirs selected in the Yong San River Basin, the sedimentation of the reservoirs has been calulated by comparing the precent capacity with original value, which revealed its reduced reservoir capacity. The reservoirs have a total catchment area of 13,871 ha. with a total capacity of 17.6 million cubic meter, and are short of water supply due to reduction of reservoir capacity. Annual sedimentation in the reservoir ranged from 120 to 3,770 cubic meter per square kilometer with great difference in its distribution, and the average value was 877 cubic meter. This wide disparity is analysed to come principally from the topography, geology, vegetation and hydraulics. The reservoir basin had a large portion of devastated land but has become green more and more in the last 10 years. It can be summarized that in the reservoirs with an average period of sedimentation of 26 years, the reduction rate of reservoir capacity amounts 12.5%, and 0.48% is shown for annual capacity reduction rate.

• Journal of Korea Water Resources Association
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• v.49 no.4
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• pp.283-291
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• 2016

As the infrastructures and populations are the condensed in the mega city, urban flood management becomes very important due to the severe loss of lives and properties. For the more accurate calculation of runoff from the urban catchment, hourly or even minute rainfall data have been utilized. However, the time steps of the measured or forecasted data under climate change scenarios are longer than hourly, which causes the difficulty on the application. In this study, daily rainfall data was disaggregated into hourly using the stochastic method. Based on the historical hourly precipitation data, Gram Schmidt orthonormalization process and K-Nearest Neighbor Resampling (KNNR) method were applied to disaggregate daily precipitation into hourly. This method was originally developed to disaggregate yearly runoff data into monthly. Precipitation data has smaller probability density than runoff data, therefore, rainfall patterns considering the previous and next days were proposed as 7 different types. Disaggregated rainfall was resampled from the only same rainfall patterns to improve applicability. The proposed method was applied rainfall data observed at Seoul weather station where has 52 years hourly rainfall data and the disaggregated hourly data were compared to the measured data. The proposed method might be applied to disaggregate the climate change scenarios.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.1991-1994
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• 2008

우리나라는 도시화, 산업화에 따른 수질저하 및 용수확보 문제를 해결하기 위하여 각종 환경기초시설의 증설과 수질개선을 위한 대책을 수립하여 왔다. 그러나 점오염원에 국한한 수질개선은 한계가 있었으며, 1995년 환경부는 전국 비점오염원 조사를 통해 비점오염원이 수질오염에 기여하는 비율이 T-N, SS는 50% 이상을 점유하고 기타 BOD, T-P도 $20{\sim}30%$ 수준임을 밝힌 바 있다. 이에 정부는 오염총량관리제를 도입하여 비점오염원의 관리를 시작하였으나, 강우시 정확한 유량자료를 바탕으로한 수질 측정자료의 부족으로 비점오염원 관리에 있어 어려움이 따르고 있다. 따라서 본 연구에서는 비점오염원 관리 및 연구를 위한 기초자료로 활용될 수 있도록 수도권 및 인근지역 주민의 식수원인 팔당호로 직유입되고, 정확한 수질자료 확보가 필요한 경안 수위관측소 지점에서 2007년 6월${\sim}$9월에 일어난 강우 중 4개의 강우사상에 대하여, 수질측정을 실시하였다. 본 연구에서 이용한 유량자료는 2007년 수위-유량관계곡선식으로 산정한 환산 유량이며, 실측한 수질자료를 바탕으로한 유량과 부하량의 관계는 통계학적으로 분석하였다. 수질측정 항목은 수온, DO, pH, EC, SS, BOD, CODMn, CODCr, T-N, T-P 등이며, BOD의 농도는 2개의 강우사상에서만 분석하였다. 현장에서 휴대용미터를 이용하여 수온, DO, pH, EC를 측정하였고, 나머지 항목은 한국건설기술연구원내 환경정밀분석 센타에 의뢰하였다. 각 항목별 유량-부하량 관계식은 기존의 지수식이 아닌 선형이나 다항식으로 산정하였다. 다항식으로 산정된 식의 결정계수($R^2$)는 BOD, T-N 항목을 제외한 각 항목에서 0.6 이상의 값을 가졌다. 항목별로 보면 SS는 0.90, $COD_{Mn}$은 0.87, $COD_{Cr}$은 0.84, T-P는 0.62의 값을 가졌다. 또한, T-N은 0.53, BOD는 0.32의 값을 가져 유량과 부하량의 관계가 거의 상관성이 없는 것으로 나타났다. BOD의 경우는 4개의 강우사상 중 2개의 강우사상에서만 분석되어 다른 항목에 비해 실측자료가 부족한 관계로 그 특성을 판단하기 어려웠다. 본 연구가 주로 홍수기에 이루어져 실측자료가 많지 않았기 때문에 본 연구의 대상지점을 대표할 수 있는 유량-부하량 관계식으로는 미흡한 한 것으로 분석되었다. 본 연구자료를 기초로 장기간 많은 자료를 확보하여 유량-부하량 관계식을 수정 보완한다면, 차후 비점오염원 관리의 기초자료로 활용될 수 있을 것으로 판단된다.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.1972-1975
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• 2008

우리 인간이 수원으로 가장 많이 이용하는 지표수의 이동 및 저장 역할을 하는 호소는 자연환경과 인간을 이어주는 중요한 매개체임은 분명하다. 그러나 최근에 경제 성장만을 위주로 발전을 추구해온 결과, 급격한 산업화에 따른 도시지역으로의 인구 집중 현상은 호소에 자연적 혹은 인위적으로 큰 영향을 주고 있다. 하천의 자정능력을 초과하여 발생하는 오염물질이 신갈 저수지로 유입되어 생태계를 파괴하고, 하천의 최종 유입지인 호소의 오염을 가중시켰다. 경기도 용인시, 화성군, 오산시 지역의 농 공업용수의 공급원으로 이용되고 있는 신갈 저수지로 유입하는 하천 역시 도시로의 인구 집중으로 인한 막대한 생활하수와 주변 지역에 조성된 공장에서 발생하는 사업장 배수의 유입으로 인해 심각하게 오염되어 신갈 저수지의 오염을 가중시키고 있다. 현재 용인시에서는 기흥 호수공원을 2010년까지 신갈 저수지 일대 118만평에 여가와 문화, 휴양시설이 연계된 대규모 유원지로 조성한다는 계획을 가지고 있다. 이에 본 연구에서는 신갈 저수지의 퇴적물 오염도를 조사하여 호수공원 조성 시 기초 데이터의 확충 및 현황파악을 위하여 신갈 저수지의 퇴적물에 대한 모니터링을 실시하였다. 측정 시기는 1차(2007년 7월)와 2차(2007년 10월)로 총 2회 실시하였으며, 조사 지점선정은 수역 전체의 특성을 가장 대표할 수 있는 지점(호심 또는 가장 깊은 곳 등), 주요 유입하천수가 유입된 후 충분히 혼합되는 지점, 호수가 유출되는 지점, 폐수나 하수의 유입으로 항상 오염이 인정되는 지점을 고려하여 신갈저수지의 6지점을 선정하여 조사하였다. 퇴적물 분석항목 중 VS, COD, T-N, T-P, 중금속 농도를 중심으로 신갈 저수지의 퇴적물 오염도를 조사하였다. 각 지점별 1차 퇴적물 조사 결과, VS $23.1{\sim}46.6\;g/kg$, COD $8.5{\sim}26.4\;mg/g$, T-N $0.35{\sim}1.52\;mg/g$, T-P $0.60{\sim}1.05\;mg/g$ 등의 농도로 조사되었으며, 중금속은 수은, 시안, 카드뮴은 검출되지 않았고 구리의 농도는 $0.1{\sim}0.6\;mg/kg$, 납의 농도는 $2.1{\sim}3.5\;mg/kg$로 조사되었다. 또한 각 지점별 2차 퇴적물 조사 결과, VS $22.8{\sim}41.4\;g/kg$, COD $7.9{\sim}21.5\;mg/g$, T-N $0.31{\sim}1.44\;mg/g$, T-P $0.82{\sim}1.01\;mg/g$ 등의 농도로 조사되었으며, 중금속은 수은, 시안, 카드뮴은 검출되지 않았고 구리의 농도는 $0.2{\sim}0.7\;mg/kg$, 납의 농도는 $2.4{\sim}3.8\;mg/kg$로 조사되었다. 본 연구의 조사 결과는 앞으로 호수공원이 조성되는 신갈 저수지를 효율적으로 관리함에 있어 중요한 근거자료가 될 수 있을 것으로 판단된다.

• Journal of Korea Water Resources Association
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• v.41 no.4
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• pp.379-394
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• 2008

Recently, extreme precipitation events beyond design capacity of hydraulic system have been occurred and this is the causes of failure of hydraulic structure for flood prevention and of severe flood damage. Therefore it is very important to understand temporal and spatial characteristics of extreme precipitation events as well as expected changes in extreme precipitation events and distributional characteristics during design period under future climate change. In this paper, climate change scenarios were used to assess the impacts of future climate change on extreme precipitation. Furthermore, analysis of future extreme precipitation characteristics and I-D-F analysis were carried out. This study used SRES B2 greenhouse gas scenario and YONU CGCM to simulate climatic conditions from 2031 to 2050 and statistical downscaling method was applied to establish weather data from each of observation sites operated by the Korean Meteorological Administration. Then quantile mapping of bias correction methods was carried out by comparing the simulated data with observations for bias correction. In addition Modified Bartlett Lewis Rectangular Pulse(MBLRP) model (Onof and Wheater, 1993; Onof 2000) and adjust method were applied to transform daily precipitation time series data into hourly time series data. Finally, rainfall intensity, duration, and frequency were calculated to draw I-D-F curve. Although there are 66 observation sites in Korea, we consider here the results from only Seoul, Daegu, Jeonju, and Gwangju sites in this paper. From the results we found that the rainfall intensity will be increased and the bigger intensity will be occurred for longer rainfall duration when we compare the climate conditions of 2030s with present conditions.

• Journal of Korea Water Resources Association
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• v.47 no.8
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• pp.717-728
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• 2014

In this study, we developed a depth-damage function based on flood damage survey with focusing on building damage in urban area. We designed items for the questionnaire survey to develop a depth-damage function which estimates the amount of damage based on inundation depth targeting Dongducheon, Korea, which has experienced severe inundation damage due to significant flooding in July 2011. Based on the survey of the area, we developed a depth-damage function and used this to estimate the real amount of damage on buildings in the inundation area. To assess the damage on buildings, we categorized buildings into two groups; namely residential buildings and commercial buildings. Also, in order to calculate the real amount of damage caused by flooding, properties and detailed damaged items were sub-divided into two groups for the survey; facilities loss (wall paper, floor paper, painting, electrical facilities, and boilers) and furnishing loss (furniture, electronic products, and daily necessities. We expect this study on the process for developing depth-damage function and on the investigation research for flooded area to help in the efficient implementation of all kinds of disaster management policies and the attainment of a society safe from disaster.

• Journal of Korea Water Resources Association
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• v.49 no.1
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• pp.1-9
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• 2016

A correlation analysis between raw water turbidity at two wide-area water treatment plants and hydrological data was conducted for efficient water supply, design and management of water treatment plant. Both correlation analysis and principal component analysis were conducted using hydrological time series data such as inflow discharge, outflow discharge, and rainfall at dam basin of intake station of wide-area water treatment plants. And, forecasting of change in turbidity was conducted using regression equation for turbidity prediction. The raw water turbidity of two water treatment plants was strongly related to time series of discharge. The raw water turbidity of Chungju water treatment plant is strongly related to outflow discharge at Chungju dam (0.708). Whereas, the raw water turbidity of Wabu water treatment plant is strongly related to inflow discharge at Paldang dam (0.805). Similar trends between turbidity forecasting result using regression equation and calculation result using estimation equation on Korea water supply facilities standard were obtained. The result of this study can provide basic data for construction and management of water treatment plant.

• Journal of Korea Water Resources Association
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• v.40 no.3
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• pp.223-236
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• 2007

Recently in urban area flood damages increase due to local concentrated heavy rainfall. Even in the cities where stormwater drainage systems are relatively well established flood damage still occurs because of the capacity limitations of the existing stormwater drainage systems. When the flood exceeds the capacity limitation of the urban storm sewer system, it yields huge property losses of public facilities involving roadway inundation to paralyze industrial and transportation system of the city. To prevent such flood damages in urban area, it is necessary to develop adequate inundation analysis model which can consider complicated geometry of urban area and artificial drainage system simultaneously. The Dual-Drainage model used in this study is the urban inundation analysis model which combines SWMM with DEM based 2-dimensional surface flood inundation model. In this study, the dual drainage model has been modified to consider the effect of complex buildings in urban area. Through the simulation of time variable inundation process, it is possible to identify inundation alert locations as well as to establish emergency action plan for the residencial area vulnerable to flood inundation.