• Journal of Korean Society on Water Environment
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• v.24 no.1
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• pp.7-18
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• 2008

The objective of this study was to develop and apply a water quality simulation model for the evaluation of ungaged watershed. The Modified WASP5 consisted of three sub-models, LOAD-M, DYN-M, and EUT-M. LOAD-M, an empirical model, estimates runoff loadings using point and non-point source data of villages. Daecheong Dam watershed was selected for the research to calibrate, verify and application of Modified-WASP5. LOAD-M model was established using field data collected from all items of water quality and water quantity gaging stations of the watersheds, and was applied to the ungauged watersheds, taking the watershed properties under consideration. The result of water quality simulation using ModifiedWASP5 shows that the observed BOD data of Yongpo and Daechong Dam in 1999 were 0.8 mg/L and 1.0 mg/L, and simulated data were 0.9 mg/L and 0.9 mg/L, respectively. In case of 1999, average BOD concentrations were 0.8 mg/L and 1.0 mg/L. Simulated concentration showed 1.1 mg/L and 1.5 mg/L, respectively. Generally, the simulation results were in good agreement with the observed data. This study was focused on formulating an integrated model for evaluating ungauged watersheds. Even though simulation results varied slightly due to limited availability of data, the model developed in this study would be a useful tool for the assessment and management of ungauged watersheds.

• Journal of Environmental Science International
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• v.18 no.6
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• pp.683-690
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• 2009

The water quality of reservoir can be controled by water quality prediction model because it can not only grasping the present water state but also predicting the water quality in future. In this study, WASP model is used to predict the water quality of Chungju reguration reservoir. This model has some special option which predicts the pollutant outflow phenomenon caused by the contamination sources. So this model is widely used because that can present the scientific basis in this field. This model can help the managers make the right choice of water quality policy. Environmental grade of Chungju reguration reservoir is in III,IV grade which is in bad condition comparatively. The water contamination will be in poor as the year passes. When considering T-N, T-P which are the nutrient to control eutrophication, the concentrated administration about contamination sources is in urgent.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.6
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• pp.65-76
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• 2012

Agricultural reservoir water quality simulation model (ARSIM-rev) was developed in this study for water quality simulation of a small and shallow agricultural reservoir with limited observed water quality data. Developed ARSIM-rev is a zero-dimensional water quality model because of little spatial differences in water quality between stations in a small and shallow agricultural reservoir. ARSIM-rev used same water quality reaction equations with WASP except for several equations, and daily based input parameters such as settling rate, release rate from sediment, and light extinction coefficient changed yearly based input parameters in ARSIM-rev. A number of pre- and post-processors were developed such as auto calibration and scenario analysis for ARSIM-rev. CE-QUAL-W2, WASP, and developed ARSIM-rev were applied to Mansu agricultural reservoir to evaluate model performance, and ARSIM-rev demonstrated similar model performance with CE-QUAL-W2 and WASP when low number of observed data was used for agricultural reservoir water quality simulation. Overall, developed ARSIM-rev was feasible for water quality simulation in a small and shallow agricultural reservoir with limited observed water quality data, and it can simulate agricultural reservoir water quality precisely enough like common water quality model such as CE-QUAL-W2 and WASP within a limited time.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.2037-2041
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• 2008

댐의 상류에서 유입되는 하천수는 상수원수의 수질농도와 직결되기 때문에 보다 심도 있는 수질관리가 필요할 것이다. 본 연구에서는 댐 상류에 위치한 저수지와 하천에서의 수질해석을 위해 WASP 모형을 사용하여 수질해석을 실시하였다. 대상구간은 강원도 횡성군의 남한강 제1지류인섬강에 위치한 횡성댐 상류 계천의 매일수위국에서부터 횡성호 구간인 13.9km에 대해 적용하였다. 이를 위해 2005년 1월부터 2006년 6월까지 매일수위국을 비롯한 주요 지점에서 측정된 수질자료를 이용하여 WASP 모형에 대한 부정정 수질모의를 실시하였으며, 이를 실측자료와 비교하여 모형에 대한 정확성을 검증하였다. 또한 하천 수질해석에 널리 사용되는 QUAL2E 모형을 대상구간에 적용하여 WASP 모형의 모의결과와 비교하여 적용성을 검토하였다.

• Journal of Korean Society on Water Environment
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• v.20 no.5
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• pp.422-431
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• 2004

Water quality modeling was performed for the purpose of diagnosis and prediction of water quality in Gyoung Choen reservoir, using EUTR05/WASP Build model. WASP Builder is capable of visual display in window and it has an advantage of updating and modification for data. Field data of 1992, Spring, Summer, and Fall, were used to calibrate model and these results were validated using data of 2000, Spring, Summer, and Fall. The reservoir was divided into 4 epilimnion segments. Water quality system for modeling were consist of BOD, Chlorophyll-a, DO, $NH_3-N$, $NO_3-N$, T-N, $PO_4-P$, T-P. The results of water quality modelling using EUTR05/WASP Builder, a range of the Correlation for calibration of BOD, T-N, T-P, and Chlorophyll-a according to three seasons are 0.63~0.90, 0.81~0.97, 0.75~0.98, and 0.77~0.98 respectively. And the correlation between simulated and observed values for verification of BOD, T-N, T-P, and Chlorophyll-a according to three seasons are 0.93, 0.94, 0.81, and 0.80 respectively. Among the pollutant sources for a basin of the Gyoung Choen reservoir, generated amount of livestock is the highest and BOD, T-N, T-P of generated loading percentage are 94%, 81%, and 95%. So, we suppose that inflow load amount will decrease 50% and increase 50% only livestock about current load amount. If increasing load amount of livestock 50% in segment 2 and 3, BOD, T-N, and T-P simulated increasing to range of $0.02~0.15mg/{\ell}$, $0.029~0.08mg/{\ell}$, $0.011~0.029mg/{\ell}$ in comparison with current water quality

• Journal of Environmental Impact Assessment
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• v.19 no.5
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• pp.465-473
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• 2010

This study was carried out to investigate the effect of EFDC hydrodynamic result on the WASP7.3 water quality modeling result in accordance with the change of number of grid for the dam reservoir to be constructed. The simulated flow and BOD, T-N and T-P loads by the HSPF watershed model was used for boundary conditions and the hydrodynamic modeling results was linked with WASP model to predict future water quality after dam construction. The scenarios for EFDC modeling were composed of Scenario 1(141 grid cells) and Scenario 2(568 grid cells). The results of Scenario 2 showed that BOD, T-N, T-P and Chl-a concentrations were decreased 0.073mg/L(8.5%), 0.032mg/L(2.6%), 0.003mg/L(6.8%), 0.644mg/L(4.2%) compared with those of Scenario 1, respectively. As number of grid cell increased, water quality concentrations were decreased and also it caused the longer running time. Therefore, this study suggests that the consideration of the geometry of water body is more important than the number of grid cells for the prediction of water quality of a dam reservoir in EIA.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.1
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• pp.15-22
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• 2009

This study reports the serial use of a 3-D hydrodynamic model, EFDC-Hydro and a dynamic water quality model WASP7.2 that are maintained by USEPA. The 48 km section of the Geum River downstream between Daechung Dam and Gongju was selected as a sample study site. Topographical information was used to accurately represent morphology of the study site and boundary conditions were derived from governmental databases including WAMIS by Ministry of Land and Ocean and WEIS by Ministry of Environment. EFDC-Hydro was successfully calibrated for observed water level and WASP was calibrated using monthly observed water quality data obtained from the above sources. It was found that the current water quality target of BOD for the Geum River-H point could not be met on monthly basis though every other tributary of the area would meet its own water quality target as assigned in Korean TMDL. This study proposed the new target BOD water quality for the Gabcheon and Mihocheon as 4.3 and 3.6 mg/l, respectively so that the Geum River-H point can meet the target. When Sejong City is constructed, it is estimated that effluent discharge limit of BOD must be less than 4.5 mg/l to meet water quality of the point. This study shows that it is possible to carry out more precise modeling considering both water movement and water kinetics by using EFDC and WASP simultaneously.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.5
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• pp.29-40
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• 2018

Even if a small amount of arsenic (As) is entering to small agricultural reservoir from upper streams, small agricultural reservoir becomes sensitive to changes in arsenic concentration depending on the water level in case of accumulation continuously because of its scale. If we want to manage arsenic concentration in small agricultural reservoir, it is very important to understand arsenic changes in agricultural reservoir. In spite of the fact that modeling is the most accurate method for analyzing arsenic concentration changes in small agricultural reservoirs, but, it is difficult to monitor arsenic change everyday. So, if data is prepared for modeling arsenic changes, water quality modeling is more effective than monitoring. Therefore, in this study, arsenic concentration changes was simulated and arsenic concentration change mechanism in small reservoir was analyzed using hydrological and water quality monitoring data and by conducting EFDC (Environment Fluid Dynamics Code)-WASP (Water Quality Analysis Simulation Program) linkage. EFDC-WASP coupling technique was very useful for modeling arsenic changes because EFDC can consider hydrodynamic and WASP can perform arsenic concentration simulation, separately. As a results of this study, during dry season, As concentration was maintained relatively high arsenic concentrations. Therefore, water level control will be needed for managing As concentration of reservoir.

• Journal of Environmental Impact Assessment
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• v.23 no.6
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• pp.432-444
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• 2014

When the water quality modelling is done with a manual calibration, it is possible that the researcher's opinion may affect the objectivity of the research. Hence, the role of the automatic calibration is highly important. This research applies a technique to automatically calibrate the water quality parameters by implementing an optimization method. This involves estimating the optimum water quality parameters targeting influential parameters towards the lake's BOD, DO, Phosphorus, Nitrogen and Phytoplankton. To accurately calculate the water temperature and hydraulic characteristics of a deep, stratifying lake, EFDC, a 3-dimensional hydraulic model which can be linked to the WASP7 was applied. With EFDC, the segment of the lake is formed and utilized as an input data of the WASP7. For the calibration of the water quality parameters of the WASP7, an influence coefficient algorithm and a genetic algorithm was applied. Of the five water quality variables for calibration, the normalized residuals of the observed and calculated values of DO, TN, CBOD were relatively small and the three water quality variables were calibrated properly. Yet the accuracy of the calibration of TP and Chl-a was relatively low.

• Korean Journal of Environmental Agriculture
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• v.16 no.3
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• pp.233-238
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• 1997

WASP5 was applied to evaluate water quality of Bokha stream with 17km of its main stem located in Ichon-city, Kyunggi province in Korea. Boundaries of the stream for the WASP5 were the Jumi bridge, 10 major tributaries and one wastewater treatment system. The stream was divided into 37 segments with about 350m length. The flowrate of the 10 day's average of the stream was obtained from the hydrograph data and the discharge-stage rating curve. Simulated quality constituents included nitrogen, phosphorus, BOD and DO. Monthly records of water quality and loads in 1996 were used for the calibration of parameters of WASP5. Simulation showed high correlations between calculated and observed concentration with monthly runoff ratio in Bokha stream. At downstream boundary, Jumi bridge [Seg.36], similar correlations were appeared. However, simulated concentrations by using annual runoff ratio were somewhat differentiated from those of the observed.