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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of The Korean Society of Civil Engineers
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Journal DOI :
Korean Society of Civil Engeneers
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Volume & Issues
Volume 22, Issue 6D - Nov 2002
Volume 22, Issue 6C - Nov 2002
Volume 22, Issue 6B - Nov 2002
Volume 22, Issue 5D - Sep 2002
Volume 22, Issue 5C - Sep 2002
Volume 22, Issue 5B - Sep 2002
Volume 22, Issue 2D - Mar 2002
Volume 22, Issue 2C - Mar 2002
Volume 22, Issue 1D - Jan 2002
Selecting the target year
Rainfall Error and Runoff Error - (I) Runoff Model Parameter Estimation and Sensitivity Analysis -
Kim, Seong-Joon ; Kwon, Hyung-Joong ; Yoo, Chul-Sang ; Ha, Eun-Ho ;
Journal of The Korean Society of Civil Engineers, volume 22, issue 6B, 2002, Pages 753~763
As a first step of the study for evaluating the error propagation from rainfall to runoff, a runoff model named KIMSTORM (Kim, 1998; Kim, et al. 1998) was introduced and applied to the Yongdam Dam Basin for its parameter estimation. Total six rainfall events were used for the model parameter estimation. As the model parameters were all estimated within 10% deviation, we could assume the possible introduction of error in the parameter estimation was relatively low. Finally, the parameter sensitivity analysis showed that the errors involved in the model parameter estimation could be sent almost linearly to the runoff error.
Rainfall Error and Runoff Error - (II) Rainfall Generation and Error Analysis -
Yoo, Chul-Sang ; Kim, Sang-Dan ; Ha, Eun-Ho ; Kim, Seong-Joon ;
Journal of The Korean Society of Civil Engineers, volume 22, issue 6B, 2002, Pages 765~775
This study investigated the runoff error depending on the number of raingauges as well as its relation to the rainfall error. The input rainfall data were generated using the WGR model proposed by Waymire et al. (1984), and then the runoff data were simulated using the distributed model named KIMSTORM. The rainfall error in this study was designed to consider the rainfall amount by setting the rainfall intensity as a weighting factor, on the other hand, the runoff error was designed to consider the runoff volume, peak flow and peak time, respectively. This study was applied to the Yongdam Dam Basin, whose results are summarized as follows. (1) Little biases can be found in the area averaged rainfall estimated using the point measurements. (2) Rainfall error decreases exponentially as the number of raingauges increases. However, the mean as well as the standard deviation of the rainfall errors do not converge to zero, but stagnates around 10% of the total rainfall amount even after using more than 10 raingauges. This seems mainly due to the spatial-temporal variability of rainfall, which may not be easily reducible. The mean and the standard deviation were found to have similar values. (3) The errors in estimation of runoff volume were found to be positively biased, which were mainly due to several highly positively skewed events. Similar patterns can also be found for the errors in the estimation of peak flow and peak time. (4) The runoff error also showed the tendency to decrease exponentially, but hardly to zero similar to the rainfall error. About 3-5 raingauges are found to be enough to stabilize the runoff error. (5) The rainfall error and runoff volume error showed 1:1 relation, an obvious results that the error in the rainfall volume transfers directly to the runoff volume. However, the rainfall error has become amplified to the runoff peak error, by about two times in this study. On the other hand, no obvious relation could be found between the rainfall error and the peak time error.
Runoff Prediction by Tank Model Using Recession Curves and Automatic Calibration of the Parameters
Kim, Woon-Joong ; Kim, Min-Hwan ; Ceon, Ir-Kweon ;
Journal of The Korean Society of Civil Engineers, volume 22, issue 6B, 2002, Pages 777~784
A simple water-tank model using recession curves is constructed to predict the rainfall-runoff process in a catchment. To acquire reliable simulation results from the model, the parameters of the model should be calibrated. lo calibrate the parameters of the model, the algorithm of Hooke and Jeeves (1961) is applied as a automatic calibration technique. The sum of the squares of differences between observed and computed hydrographs is used for the objective function. The rate of runoff and the time lag between rainfall and runoff were determined from rainfall and hydrograph. The model is applied to Sumjindam catchment for predicting flood response to rainfall events. As a result, the parameters of the model were calibrated rapidly and the predicted value by the model coincided well with observed value.
Turbulence Modeling of Compound Open-Channel Flows Using Nonlinear
Joung, Young-Hoon ; Choi, Sung-Uk ;
Journal of The Korean Society of Civil Engineers, volume 22, issue 6B, 2002, Pages 785~793
This paper presents a numerical model to investigate the mean and turbulence characteristics of compound open-channel flows. The nonlinear
model, which is a non-isotropic turbulence model, is used for the turbulence closure. The experimental case in Tominaga and Nezu (1991) is simulated by the numerical
model. The predicted isovel shows the secondary currents over the entire cross section and the twin vortices especially at the interface between the floodplain and the main channel. The magnitude of the secondary currents is seen to be similar to the observed one. The computed profiles of the bottom shear stress, eddy viscosity, Reynolds stress, and the turbulence kinetic energy appear to agree well with the measured data. Through the comparison with the profiles by the standard
model, the effect of isotropic turbulence assumption on the numerical computation is also investigated.
Capability of Evapotranspiration Estimation with Short Field Data
Oh, Nam-Sun ; Lee, Khil-Ha ; Ko, Young-Chan ;
Journal of The Korean Society of Civil Engineers, volume 22, issue 6B, 2002, Pages 795~801
This paper presents the application of the different methods to evaluate the evapotranspiration. A high degree of accuracy in calculating potential evaporation might not be possible since various assumptions and simplifications of model inputs were required due to the limited nature of the input data. Some methods presented here is, however, encouraging in that they are feasible in the area in which many parameters required as input have measured in no field experiments. First, evapotranspiration is evaluated by a physically-based Soil-Vegetation Atmosphere Transfer Scheme (SVATS), and next, comparatively simple semi-empirical methods are utilized to evaluate evapotranspiration. Both are compared with a field experimental data. The results shows a tolerable accuracy and Hargreaves equation is very encouraging because of it's less requirement of input parameters. In the following, it is expected to contribute to the effective and consistent management of the water resources.
Effects of Sludge Pre-Treatment on the Performance of Membrane-Coupled Aerobic Digestion
Yeom, Ick-Tae ; Lee, Ki-Ryong ; Kwon, Jae-Hyun ; Kim, Hyung-Soo ;
Journal of The Korean Society of Civil Engineers, volume 22, issue 6B, 2002, Pages 803~809
The effects of ozone and alkaline pre-treatment of sewage sludge on the performances of membrane-coupled aerobic sludge digestion were investigated. In particular, the effects of sludge pre-treatment on the sludge degradation and the stability of membrane filtration were evaluated. Three sets of reactors were operated under three conditions of sludge treatment; 1) ozone treatment at 0.1 gram ozone per gram SS of the influent sludge, 2) alkaline treatment at pH 12, 3) no pre-treatment. Without sludge pre-treatment, 27% of SS reduction was obtained at the HRT of 5 days. With ozone treatment and alkaline treatment, the average SS reduction increased to 84% and 76%, respectively, at the same HRT. Membrane fouling occurred earliest with the non treated sludge and the alkaline treated sludge, the next. With ozone treated sludge, stable membrane filtration for more than 200days was possible without any kind of membrane washing. The viscosity of the MLSS in the reactor fed with ozone treated sludge was relatively low indicating the role of ozone treatment in controlling membrane fouling. In conclusion, sludge pre-treatment followed by aerobic digestion in a membrane-coupled bioreactor can achieve a very high rate of sludge reduction at a relatively short HRT. Ozone treatment appears to be more advantageous in terms of both the sludge reduction efficiency and the membrane fouling control.
Evaluation of Water Supply Capacity for Multi-Purpose Dam Using Optimization and Simulation Techniques
Yi, Jae-Eung ; Song, Jai-Woo ;
Journal of The Korean Society of Civil Engineers, volume 22, issue 6B, 2002, Pages 811~818
Water supply capacity of multi-purpose dam means the amount of water that can be supplied from reservoir formed by dam. The evaluation of water supply capacity for a dam is an essential element for establishment of water supply planning such as new water resources securing and reservoir size determination. The evaluation of water supply capacity is very important process not only for a multi-purpose dam itself but also for basin-wide water resources system scheduling and operation. Water supply capacity of Yongdam multi-purpose reservoir is evaluated using simulation and optimization techniques in this study. Applying 35 years stream data from 1963 to 1997, water supply capacity of Yongdam multi-purpose reservoir is estimated as 648.7MCM by a simulation technique and 680.01MCM by a optimization technique based on 95% reliability.
Optimal Design of the Monolithic Vertical Caisson of Composite Breakwaters by the Minimization of Expected total Lifetime Costs
Lee, Cheol-Eung ;
Journal of The Korean Society of Civil Engineers, volume 22, issue 6B, 2002, Pages 819~831
A minimization of expected total lifetime costs is formulated by incorporating the results of reliability analyses in the economic analyses, from which the optimal width of vertical caisson of composite breakwaters may be determined. lo minimize the expected total lifetime costs consisted of the expected initial construction costs and the expected damage costs due to sliding failure such as the optimal technique, all of expected costs in economic analyses should be defined as a function of design variable, the width of vertical caisson of composite breakwaters. Additionally, the minimization of expected total lifetime costs uses a exponential function so that the probability of sliding failure resulting from the reliability analyses can be related to the width of vertical caisson directly. The variations of economical growths and interest rates are taken into account by the introduction of net annual discount rate by which the future damage values due to sliding failure can be accounted the present values. Applying the minimization of expected total lifetime costs to the fictitious composite break-waters, it is confirmed that the optimal design variable can be determined in the sense that the expected total lifetime costs is minimized. Also, the overall trends of results are in a good agreement with the those of the previous several studies. From the sensitivity analyses, it is finally concluded that the minimization of expected total lifetime costs may be applied straightforwardly to the optimal designs of the vertical caisson of composite breakwaters if the economic analyses such as the expected initial construction costs and the damage costs are evaluated correctly.
Applicability Evaluation of One Dimensional Consolidation Theory to the New Type Soft Ground Breakwater
Kwon, O-Soon ; Jang, In-Sung ; Park, Woo-Sun ; Yum, Ki-Dai ;
Journal of The Korean Society of Civil Engineers, volume 22, issue 6B, 2002, Pages 833~842
In constructing breakwaters, which have generally been located on a soft ground in Korea recently, considerable expenditure and time consumption are required for a ground improvement. Therefore, a new type of breakwater applicable to soft ground conditions was developed with considerations of economy and stability, and the evaluation on the behavior of the soft ground breakwater has also been investigated. In this study, the consolidation behavior of the soft ground breakwater was analyzed from the laboratory model test, and its applicability was examined by comparing with consolidation settlement based on Terzaghi's one dimensional consolidation theory. It is found that a validity of square root-t method, which was utilized to eliminate the effect of initial settlement from total settlement, was verified. lest results also reveal that the Terzaghi's one dimensional consolidation theory can conservatively be adopted with some accuracy if assumed the location of the consolidation loading is an end of the bottom wall.
Statistical Near Field Mixing Characteristics of Sokcho Outfall Plumes by the Oceanographic Field Observation
Kang, See-Whan ; Kim, Young-Do ; Kim, Sang-Ik ; Oh, Byung-Cheol ;
Journal of The Korean Society of Civil Engineers, volume 22, issue 6B, 2002, Pages 843~850
Near Field mixing characteristics of Sokcho outfall plumes were investigated using NRFIELD model on the basis of oceanographic field observations. Ocean currents and tidal elevations were observed near the discharging area, and effluent flowrates and temperature were also monitored at Sckcho wastewater treatment plant for 57 days between November 15,2000 and January 20,2001. The results show that wide range of variability in the Sokcho oufall's mixing characteristics during the observation period occur due to the temporal changes in oceanic ambient and effluent conditions. Near-field dilutions were ranged from 58 to 325, with the averaged dilution of 90, and mixing zone length were ranged from 6.4m to 104.1m with the average length of 18.7m. For 33% of the whole observation period ambient current velocity is smaller than 5 cm/sec, that is, ambient Fruode number is smaller than 0.1, the ambient current did not affect the dilution behavior. In this period, the mixing zone length were limited to about 6.5m.
Influence of pH on the Hydrolysis and Acidogenesis of Food Waste
Song, Young-Chae ; Woo, Jung-Hui ; Paik, Byeong-Cheon ;
Journal of The Korean Society of Civil Engineers, volume 22, issue 6B, 2002, Pages 851~857
Influence of pH on the anaerobic hydrolysis and acidogenesis was investigated to determine the proper alkalinity requirement in the fermentation of food waste. Two completely mixed acidogenic reactors were used for the experiment. The food waste was obtained from a university dining hall and shattered after removal of impurities and screening with a sieve. The prepared food waste was intermittently fed into the reactor once a day and the organic loading rate was 5 g VS/L/d. During the experiments, dilution water was supplied continuously into the reactors and the flow rate was 4.29L/d. When the alkalinity in the dilution water was controlled to at 3,000 mg/L, 5,000 mg/L and 8,000mg/L as
, the pH values of the acidogenic reactor were maintained around 5.3, 6.3 and 7.0, respectively, at steady state. The hydrolysis of particulate food waste was improved from 32.1% to 55.2% according to the increase of pH from 5.3 to 7.0. However, at lower pH around 5.3, the acidification percentage of hydrolyzed organics was higher as 82.2% than those of higher ranges of pH. The major components of VFAs produced from the acidogenesis of food waste were the short chain fatty acids such as acetic acid, propionic acid, and butyric acid. However, the contents of valeric and caproic acid were gradually increased according to the decrease of the pH from 7.0 to 5.3.
Evaluation for Practical Utility on the Anaerobic Acidogenesis of Municipal Primary Sludge
Kim, Hyeong-Seok ; Kho, Hyun-Woong ; Sung, Nak-Chang ;
Journal of The Korean Society of Civil Engineers, volume 22, issue 6B, 2002, Pages 859~864
Anaerobic acidogenesis of municipal primary sludge is one way of producing external carbon sources within sewage treatment plant. The practical utility was evaluated for the TVA (Total Volatile Acids) production by anaerobic acidogenic of primary sludge on the sewage treatment plant. The reactor was fed with primary sludge alone and operated HRT 1.5 day at
. Results show that SCOD/TCOD ratio was 8.2%, average TVA production rate was
and average SCOD production rate was
. In the batch denitrification tests, the denitrification efficiency was about 39.6%, and the contents of SCOD which can be external carbon source in denitrification process was about 34%. The required gCOD for
Advenced Estimation Method for Leachate Production from Sanitary Landfill Using Modified HELP Model
Seo, Sang-Won ; Hwang, Sun-Jin ; Whang, Gyu-Dae ;
Journal of The Korean Society of Civil Engineers, volume 22, issue 6B, 2002, Pages 865~872
Among the several disposal methods of municipal solid waste (MSW), above half of the MSW disposal is depends on landfill as for present. Most of the landfill sites being under construction are sanitary landfill that has leachate collection and treatment facilities to prevent pollution of its surroundings. For the reason, accurate estimation of leachate production from a landfill site by a reliable method becomes very important. The objective landfill site of this study is the Landfill Zone-1 (LZ-1) of Sudokwon Landfill Site (SLS). It covers total area of 4.08 million square meters with filled-up area of 2.5 million square meters. And it has a landfill capacity of 64million cubic meters. Landfilling of LZ-1 was started in 1992, February and ended in 2000, October. Leachate from the three ways i.e. bottom layer of landfill site
, slope of landfill site
and condensed water from landfill gas (LFG)
were calculated for to estimate total amount of leachate from LZ-1 of SLS.
were calculated with HELP Model, and
was put equal to the amount of condensed water generated from LFG. And LFG production was estimated with LAEE Model. As a result it could be said that
at the early stage increased to the range of
with serious seasonal fluctuations and because of precipitation,
increased gradually up to
, it was determined to be generated maximum
. The sum of three estimated amount
showed a range of
and actual amount of leachate from SLS was reported as
. So it was known that methods and logics applied in this study for to estimate the leachate production from SLS were considerably valid.