• 상하수도학회지
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• 제25권5호
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• pp.751-757
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• 2011

The monitoring technique based on electrical conductivity (EC) can provide researchers with some advantages in maintenance management and is cost-effective as compared with existing CSOs monitoring. In this study, the flow rate estimation using EC data was executed in two sites where storm overflow chamber had installed. In the result of A-site, R2 of second order multinomial between dilution ratio of EC and observed flow rate was showed the range of 0.68 ~ 0.77. And $R^{2}$ of B-site was 0.62 ~ 0.81. On the other hand, cumulative frequency of A-site was 43.4 ~ 52.2% in the relative error level of under 20%. And B-site was 10.1 ~ 46.5%. The flow rate estimation formula was improved through consideration of some parameters including antecedent dry days and rainfall duration. And difference between estimated flow rate and observed flow rate in total rainfall event was very small.

• 한국수자원학회논문집
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• 제40권7호
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• pp.511-521
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• 2007

본 연구에서는 제주도내 강우 관측자료를 활용하여 강우지속시간 및 표고에 따른 강우량 보정기법을 개발하였다. 이를 위해 기상청 관측소(기상관서:4개소, AWS:13개소)의 시우량 자료와 표고별 분포를 이용하여 표고와 강우지속 시간에 대한 다항회귀분석을 수행하였다. 회귀된 모형의 평가에서 강우지속시간은 표고보다 강우량과 좋은 상관성을 나타내었으며, 강우량 보정시 표고만을 고려한 모형은 과대한 보정을 하였다. 따라서 수자원 설계시 기존의 표고만을 고려한 모형보다 본 연구에서 제시된 강우지속시간 및 표고를 동시에 고려한 모형을 적용할 경우 실제 강우 사상을 더욱 잘 반영할 것으로 판단된다. 그러나 본 연구에서 제시된 모형은 향후 부족한 표고별 강우 관측소와 짧은 강우 관측기간 등에 대한 보완이 필요하다.

• 한국수자원학회논문집
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• 제44권1호
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• pp.41-49
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• 2011

본 연구는 한 유역 내에서 단위유량도의 첨두치가 강우 강도에 따라 변동되는 기존 연구 분석 사례를 근간으로 하여 고찰된다. 시간불변이라는 이론적 기본 가정과 달리 호우별 강우강도에 따라 시변(時變)하는 단위유량도를 설정하고 강우사상에 적용하여 유출수문곡선을 산출하여 검토한다. 이 때 적용되는 단위유량도의 경우 첨두유량과 첨두발생시간은 기왕 연구된 강우강도와의 관계식을 검토하여 이용하고 단위유량도 형상은 산출된 첨두치를 적용한 Nash의 단위유량도로 설정된다. 비교 목적을 위해서 적용하는 유역 평균 단위유량도는 강우사상별로 유도된 26개의 단위유량도의 평균 첨두치에 의한 Nash의 모형이다. 호우사상의 강우강도별로 변동되는 단위유량도와 평균단위유량도로부터 산출된 수문곡선의 첨두유량과 첨두발생시간을 관측수문곡선과 비교한다. 비교한 결과 본 연구에서 보완적으로 제시한 시변(時變)의 단위유량도는 평균 단위유량도에 의해서 계산한 첨두홍수량과 첨두발생시간 보다 관측치에 접근함을 보인다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2005년도 학술발표회 논문집
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• pp.583-587
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• 2005

At present, various methods are available to analyze storm runoff data. Among these, application of Z-transform is comparatively simple and new, and the technique can be used to identify rainfall and unit hydrograph from analysis of a single storm runoff. The technique has been developed under the premise that the rainfall-runoff process behaves as a linear system for which the Z-transform of the direct runoff equals the product of the Z-transforms of the transfer function and the rainfall. In the hydrologic literatures, application aspects of this method to the rainfall-runoff process are lacking and some of the results are questionable. Thus, the present study provides the estimation of Z-transform technique by analyzing the application process and the results using hourly runoff data observed at the research basin of International Hydrological Program (IHP), the Pyeongchanggang River basin. This study also provides the backgrounds for the problems that can be included in the application processes of the Z-transform technique.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2002년도 학술발표회 발표논문집
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• pp.245-248
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• 2002

The Soil Conservation Service (SCS) developed a unique procedure for estimating direct runoff from storm rainfall. But, It is very difficult to estimate accurately flood hydrograph by SCS method, because the initial ion of Ia(0.2Sa) itself has lots of systematic errors and there is no investigation on Ia in the Korean watershed. The maximum storage capacity of Umax is calibrated in the DAWAST model and is related to the present ability of rainfall to be infiltrated into the unsaturated soil. Effective rainfall for design and real-time flood hydrograph can be estimate more reasonably by introducing new Ia relationship made from the rainfall-runoff data observed in the Korean watersheds.

• Environmental Engineering Research
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• 제22권1호
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• pp.87-94
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• 2017

This study was conducted to determine the effect of the climate change to the level of groundwater recharging. This research was conducted on the watershed of Bangga by using the Soil Water Balance of MockWyn-UB model. Input data compose of evapotranspiration, monthly rainfall, watershed area, canopy interception, heavy rain factor and the influence of climate change factors (rainfall and temperature). The conclusion of this study indicates that there is a decreasing trend in annual groundwater recharge observed from 1995 to 2011. The amount of groundwater recharge varied linearly with monthly rainfall and between 3% to 25% of the rainfall. This result implies that rain contributed more than groundwater recharge to runoff and evaporation and the groundwater recharge and Bangga River discharge depends largely on the rainfall. In order to increase the groundwater recharge in the study area, reforestation programmes should be intensified.

• 한국환경보건학회지
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• 제31권1호
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• pp.1-6
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• 2005

This study was conducted to identify the runoff characteristics of non-point source according to rainfall in Nam watershed. Land-uses of the Nam watershed were surveyed paddy field 4.5%, crop field 6.8%, mountainous 78.7%, urban 2.4%, and etc. 7.7%. Mean runoff coefficients in each area were observed Ⅰ area 0.08, Ⅱ area 0.08, and Ⅲ area 0.05. In the relationship between the rainfall and peak-flow, correlation coefficients(r) were investigated Ⅰ area -0.8609, Ⅱ area 0.6035, and Ⅲ area -0.4913. In the relationship between the antecedent dry period and first flow runoff, correlation coefficients(r) were investigated Ⅰ area -0.9093, Ⅱ area -0.1039, and Ⅲ area -0.7317. The discharge of pollutant concentrations relates to the flow rate of storm-water. In the relationship between the rainfall and watershed loading, exponent values of BOD, COD, SS, and T-N were estimated to 1.2751, 1.2003, 1.3744, and 1.1262, respectively.

• 한국농공학회지
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• 제37권3_4호
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• pp.48-60
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• 1995

A flood - flow forecasting system model of river basins has been developed in this study. The system model consists of the data management system(the observation and telemetering system, the rainfall forecasting and data-bank system), the flood runoff simulation system, the reservoir operation simulation system, the flood forecasting simulation system, the flood warning system and the user's menu system. The Multivariate Rainfall Forecasting model, Meteorological factor regression model and Zone expected rainfall model for rainfall forecasting and the Streamflow synthesis and reservoir regulation(SSARR) model for flood runoff simulation have been adopted for the development of a new system model for flood - flow forecasting. These models are calibrated to determine the optimal parameters on the basis of observed rainfall, 7 streamfiow and other hydrological data during the past flood periods.

• 한국농공학회지
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• 제42권3호
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• pp.76-88
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• 2000

AGNPS model is applied in this study to analyze the changes of non-point source pollutant according to AMC condition using probable rainfall. Probable rainfall of H-dam area by Gumber's extreme value distribution is computed through frequency analysis for each return period. 35 coarse grids are subdivided into 134 find grids of finite differential network to analyze peak flow soil loss quantity and nutrients of study area and the modified CN estimation equation shows good result about rainfall events-peak flow relationship. And as the consequence of estimation of soil loss quantity for each rainfall event soil loss quantity shows 120%-170% of actual soil loss quantity Regression analysis for the observed and calculated values of flow T-P AMC has an important effect on nutrients concentration of outflow and it if found that the excessive fertilization under AMC III condition may cause eutrophication by nutrients because the range of increase of outflow concentration appears relatively high.

• 한국농공학회논문집
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• 제46권4호
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• pp.25-36
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• 2004

This study was conducted to derive the design rainfall by the consecutive duration using the at-site frequency analysis. Using the errors, K-S tests and LH-moment ratios, Log Pearson type 3 (LP3) and Generalized Extreme Value (GEV) distributions of Gamma and Non-Gamma Family, respectively were identified as the optimal probability distributions among applied distributions. Parameters of GEV and LP3 distributions were estimated by the method of L and LH-moments and the Indirect method of moments respectively. Design rainfalls following the consecutive duration were derived by at-site frequency analysis using the observed and simulated data resulted from Monte Carlo techniques. Relative root-mean-square error (RRMSE) and relative efficiency (RE) in RRMSE for the design rainfall derived by at-site analysis in the observed and simulated data were computed and compared. It has shown that at-site frequency analysis by GEV distribution using L-moments is confirmed as more reliable than that of GEV and LP3 distributions using LH-moments and Indirect method of moments in view of relative efficiency.