• Title, Summary, Keyword: Rainfall condition

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Analysis of Performance Characteristic for Small Scale Hydro Power Plant with Rainfall Condition Change (강우형태 변화에 의한 소수력발전소 성능특성분석)

  • Park, Wan-Soon;Lee, Chul-Hyung
    • 한국신재생에너지학회:학술대회논문집
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    • pp.614-618
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    • 2009
  • The effects of design parameters for small scale hydro power(SSHP) plants due to rainfall condition have been studied. The model to predict hydrologic performance for SSHP plants is used in this study. The results from analysis for rainfall conditions based on KIER model show that the capacity and load factor of SSHP site had large difference between the period. Especially, the hydrologic performance of SSHP site such as design flowrate due to rainfall condition of recent period varied sensitively. And also, the methodology represented in this study can be used to decide the primary design specifications of SSHP sites.

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Estimation of Discharge Load due to Combined Sewer Overflows in the Management of Total Maximum Daily Loads (수질오염총량관리 관거월류부하 변화에 따른 배출부하량 산정방법)

  • Park, Jun Dae;Oh, Seung Young;Choi, Ok Youn
    • Journal of Korean Society on Water Environment
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    • v.27 no.3
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    • pp.293-299
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    • 2011
  • The quantity of a discharge load can change with changes in rainfall in the area with a combined sewer system (CSS). To evaluate the implementation appropriately in the management of total maximum daily loads (TMDLs), the effects of rainfall changes should be considered in the estimation of the discharge load. The rainfall condition for the estimation of the discharge load in a certain year should be standardized to the same rainfall condition as that of the reference year. However, the calculation process is very complicated with its potential limitations. This study investigated and developed relatively simple methods for estimating the discharge load. Load conversion method (LCM) is designed to convert the discharge load under the current rainfall condition into that of the reference rainfall conditions. Simple rainfall data method (SRDM) is to simplify the estimation process of the discharge load by the simple conversion of rainfall data. These methods were applied to calculate the discharge load and examine the estimation results. From the results of this study the application of these methods may be useful for estimating the discharge load in the TMDL process.

Changes of Outflow with Time Varied Monthly Rainfall Data (월강우의 시간분포에 따른 유출량 변화)

  • Hwang, Man-Ha;Kang, Shin-Uk
    • Proceedings of the Korea Water Resources Association Conference
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    • pp.1967-1971
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    • 2007
  • In general, outflow is larger with rainfall but it is various in the initial moisture condition of basin and condition of rainfall distribution in both time and space. In this study, changes of outflow with time varied rainfall data were analyzed in the basin in which the moisture distribution is constant. Outflow differences with rainfall intensive of first period, middle period, and last period of month are 6.1% in January, 7.8% in February, 9.8% in March, 22.6% in April, 15.7% in May, 19.1% in June, 22.6% in July, 22.4% in August, and 16.8% in september respectably. The results show that 10 days outflow differences are ranged from 6.1% to 22.6% under the constant moisture condition, Outflow differences in the flood seasons are larger than them in the drought seasons.

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Analysis of rainfall infiltration characteristics for unsaturated soils using a column test equipment (모형실험장치를 이용한 불포화토의 강우 침투특성 분석)

  • Park, Kyu-Bo;Chae, Byung-Gon;Kim, Kyeong-Su
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.736-742
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    • 2010
  • This study was conducted to characterize on the relationships of rainfall intensity and infiltration rate of rainfall dependent on unit weight change in the gneissic weathered soil by a column test equipment. In this study, volumetric water content and pore water pressure were measured using TDR sensors and tensiometers at regular time intervals. Rainfall conditions including continuous rainfall and repeated rainfall were selected in order to know the effect of antecedent rainfall. In the condition of rainfall intensity 20mm/h and the unit weights of soil as $1.35g/cm^3$, $1.55g/cm^3$ and $1.61g/cm^3$, average rainfall infiltration rate was $2.814{\times}10^{-3}cm/sec$, $1.969{\times}10^{-3}cm/sec$ and $1.252{\times}10^{-3}cm/sec$ respectively. The higher rainfall intensity and lower unit weight of soil, the faster average infiltration rate. Overflow in the column was happened except rainfall condition of rainfall intensity 20mm and soil unit weight $1.35g/cm^3$. Increasing the soil unit weight, overflowed water was increased and occurrence time was faster.

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SCS Curve Number and temporal Variation of Rainfall (강우의 시간분포를 고려한 CN값 산정)

  • Cho, Hong-Je;Lee, Tae-Young
    • Journal of Korea Water Resources Association
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    • v.36 no.2
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    • pp.183-193
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    • 2003
  • A relation between the temporal variation of rainfall and direct runoff was characterized using temporal indexes of rainfall(1st, 2nd, 3rd, and 4th moment). Curve Number has a relation with 1st and 2nd moment for AMCIII condition when the rainfall duration is relative (10th quantile). Also peak runoff ratio(QP/Q) has a relation with 1st and End moment for AMCIII condition as well as 3rd and 4th moment for AMC I condition. Considering all durations of rainfall, alternatively, Curve Number has a relation with 1st and 2nd moment for AMCIIIcondition besides every moments for AMC I condition. But peak runoff ratio(QP/Q) has few relations excepting 3rd and 4th moment for AMC I condition. As a results, temporal indexes of rainfall are useful to determine curve numbers regarding the temporal variation of rainfall.

Analyzed Change of Soil Characteristics by Rainfall and Vegetation (강우 및 식생에 의한 토질특성 변화 분석)

  • Lee, Moon-Se;Kim, Kyeong-Su;Song, Young-Suk;Ryu, Je-Cheon
    • The Journal of Engineering Geology
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    • v.19 no.1
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    • pp.33-41
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    • 2009
  • In this study, some changes of soil characteristics in a field were analyzed to investigate the effect of heavy rainfall during rainy season. The heavy rainfalls were often induced geohazards like landslides. To do this, the reaching rainfall in the ground surface was investigated according to a condition of vegetation, and the change of soil characteristics induced by infiltrating rainfall was analyzed. The study site is a natural terrain located in Daedeok Science Complex. This site has same geology and soil condition whereas it has different vegetable condition. The rainfall records during the rainy season of 2006 and 2007 were selected. The rainfall records are based on the measuring date from Daejeon Regional Meteorological Administration adjacent to the study site. Also, the rainfall records according to the condition of vegetation were measured using rainfall measuring device made by ourselves. The soil tests were carried out about soil specimen sampled before and after rainfall, and then the change of soil characteristics related to rainfall and vegetation were analyzed. As the result, the density of vegetation was influenced by reaching rainfall quantity in the ground surface, and its influence intensity was decreased with rainfall intensity and rainfall duration. Also, it shows that degree of saturations, water contents, liquidities and shear resistances are directly influenced by heavy rainfalls.

Characteristics of Rainfall and Landslides according to the Geological Condition (지질조건에 따른 강우와 산사태의 특성분석)

  • Kim Kyeong-Su;Song Young-Suk;Cho Yong-Chan;Kim Won-Young;Jeong Gyo-Cheol
    • The Journal of Engineering Geology
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    • v.16 no.2
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    • pp.201-214
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    • 2006
  • To study the relationship between rainfall conditions and landslides according to a geological condition in land-slides areas such asJangheung Kyounggi, Sangju and Pohang Kyoungbuk, the data of rainfall and landslides are investigated and analyzed. Many landslides occurred at these areas because of the heavy rainfall in two or four days of the summer 1998. The data of rainfall are collected in observatories within a 50km radius from landslides occurrence areas, and the data of landslides are investigated directly in landslides areas. The data of rainfall are the accumulative rainfall and the rainfall intensity, and the data of landslides are the occurrence frequency considering the geological condition. These data are analyzed statistically to know the relationship the rainfall and landslides. The landslides are concentrated in the heavy rainfall area from the analysis of these data. It knows that the land-slides are triggered by the heavy rainfall. Meanwhile, the rainfall factors such as the accumulative rainfall, the rain-fall intensity and the dropping time are different in each landslides area, and the shape and frequency of landslides are different respectively. The landslides have occurred in the area of high accumulative rainfall, while the land-slides have not occurred around that area. Therefore, the rainfall is very important factor induced by the landslides, and the accumulative rainfall is really related to the frequency of landslides.

Variation of Non-Point Source Pollution according to AMC Condition Using Probable Rainfall (확률강우량을 이용한 AMC 조건에 따른 비점원 오염량의 변화)

  • 안승섭
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.42 no.3
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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.

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Analysis on Design Parameters of Small Hydropower Sites with Rainfall Conditions (강우상태에 따른 소수력발전입지의 설계변수 특성 분석)

  • Lee, Chul-Hyung;Park, Wan-Soon
    • Journal of the Korean Solar Energy Society
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    • v.32 no.4
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    • pp.59-64
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    • 2012
  • The correlation between hydrologic performance design parameters of small hydro power(SHP) sites and rainfall condition have been analyzed for major river systems. The model, which can predict flow duration characteristic of stream, was developed to estimate the inflow caused from rainfall. And another model to predict hydrologic performance for SHP plants is established. Based on the models developed in this study, the hydrologic performance characteristics for SHP sites have been analyzed. The results show that the hydrologic performance characteristics of SHP sites have some difference between the river systems. Especially, the specific design flowrate and specific output of SHP sites located on North Han river and Nakdong river systems have large difference compared with other river systems. It was found that the hydrologic performance design parameters such as specific design flowrate and specific output were affected by rainfall condition in basin area of SHP sites.

Evaluation and Forecasting Model for State of Drought in the Irrigation Reservoir (관개저수지의 한발평가 및 예측모형(관개배수 \circled2))

  • 이성희;이재면;김태철
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • pp.187-192
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    • 2000
  • The severity of drought could be evaluated by the accumulative rainfall method, soil moisture condition method, storage ratio method, and water supply restriction intensity method, etc. The pattern of drought could be forecast with the most similar pattern of accumulative rainfall out of the file of past rainfall history. The information that how much rainfall should be expected to overcome the present drought could be obtained from the reservoir storage ratio and soil moisture condition.

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