• Title/Summary/Keyword: Water quality level model

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Estimation of Daily Solar Radiation at the Missing Point for Water Quality Impact Assessment in Nakdong River Watershed: Comparison of Modified Angstrom Model and Transmittance interpolation Model (수질 영향평가 신뢰수준 향상을 위한 낙동강 유역 미관측 지점에서의 일사량 추정: 수정형 Angstrom모형과 투과율모형의 비교)

  • Lee, Khil-Ha
    • Journal of Environmental Impact Assessment
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    • v.21 no.1
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    • pp.219-227
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    • 2012
  • Daily solar radiation is essential for water resources planning and environmental impact assessment. However, radiation data is not commonly available in Korea other than in big cities, and there has been no direct measurement for rural areas where water resources planning and environmental impact assessment is usually most needed. In general, missing radiation data is estimated from nearby regional stations within a certain distance, and this study compared two dominant methods (modified Angstrom equation and transmittance interpolation method) at six stations in Nakdong River watershed area. Two methods shows a similar level of accuracy but the transmittance interpolation method is likely to be superior in that there is no need for any measurement element since the modified Angstrom equation require the sunshine hour measurement. This study will contribute to improve water resource and water quality management in Nakdong River watershed.

Development and Assessment of a Dynamic Fate and Transport Model for Lead in Multi-media Environment

  • Ha, Yeon-Jeong;Lee, Dong-Soo
    • Environmental Engineering Research
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    • v.14 no.1
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    • pp.53-60
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    • 2009
  • The main objective was to develop and assess a dynamic fate and transport model for lead in air, soil, sediment, water and vegetation. Daejeon was chosen as the study area for its relatively high contamination and emission levels. The model was assessed by comparing model predictions with measured concentrations in multi-media and atmospheric deposition flux. Given a lead concentration in air, the model could predict the concentrations in water and soil within a factor of five. Sensitivity analysis indicated that effective compartment volumes, rain intensity, scavenging ratio, run off, and foliar uptake were critical to accurate model prediction. Important implications include that restriction of air emission may be necessary in the future to protect the soil quality objective as the contamination level in soil is predicted to steadily increase at the present emission level and that direct discharge of lead into the water body was insignificant as compared to atmospheric deposition fluxes. The results strongly indicated that atmospheric emission governs the quality of the whole environment. Use of the model developed in this study would provide quantitative and integrated understanding of the cross-media characteristics and assessment of the relationships of the contamination levels among the multi-media environment.

Prediction of the DO concentration using the machine learning algorithm: case study in Oncheoncheon, Republic of Korea

  • Lim, Heesung;An, Hyunuk;Choi, Eunhyuk;Kim, Yeonsu
    • Korean Journal of Agricultural Science
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    • v.47 no.4
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    • pp.1029-1037
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    • 2020
  • The machine learning algorithm has been widely used in water-related fields such as water resources, water management, hydrology, atmospheric science, water quality, water level prediction, weather forecasting, water discharge prediction, water quality forecasting, etc. However, water quality prediction studies based on the machine learning algorithm are limited compared to other water-related applications because of the limited water quality data. Most of the previous water quality prediction studies have predicted monthly water quality, which is useful information but not enough from a practical aspect. In this study, we predicted the dissolved oxygen (DO) using recurrent neural network with long short-term memory model recurrent neural network long-short term memory (RNN-LSTM) algorithms with hourly- and daily-datasets. Bugok Bridge in Oncheoncheon, located in Busan, where the data was collected in real time, was selected as the target for the DO prediction. The 10-month (temperature, wind speed, and relative humidity) data were used as time prediction inputs, and the 5-year (temperature, wind speed, relative humidity, and rainfall) data were used as the daily forecast inputs. Missing data were filled by linear interpolation. The prediction model was coded based on TensorFlow, an open-source library developed by Google. The performance of the RNN-LSTM algorithm for the hourly- or daily-based water quality prediction was tested and analyzed. Research results showed that the hourly data for the water quality is useful for machine learning, and the RNN-LSTM algorithm has potential to be used for hourly- or daily-based water quality forecasting.

Simulation for Chlorine Residuals and Effect of Rechlorination in Drinking Water Distribution Systems of Suwon City (수원시 상수관망에서 잔류염소와 재염소주입의 효과 예측)

  • Kim, Kyung-Rok;Lee, Byong-Hi;Yoo, Ho Sik
    • Journal of Korean Society of Water and Wastewater
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    • v.14 no.1
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    • pp.108-116
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    • 2000
  • Chlorine is widely used as a disinfectant in drinking-water systems throughout the world. Chlorine residual was used as an indicator for prediction of water quality in water distribution systems. The variation of chlorine residual in drinking water distribution systems of Suwon city was simulated using EPANET. EPANET is a computerized simulation model which predicts the dynamic hydraulic and water quality behavior within a water distribution system operating over an extended time period. Sampling and analysis were performed to calibrated the computer model in 1999 (Aug. Summer). Water quality variables used in simulations are temperature, roughness coefficient, pipe diameter, pipe length, water demand, velocity and so on. Extended water residence time affected water quality due to the extended reaction time in some areas. All area showed the higher concentration of chlorine residual than 0.2mg/l(standard). So it can be concluded that any area in Suwon city is not in biological regrowth problem. Rechlorination turned out to be an useful method for uniform concentration of free chlorine residual in distribution system. The cost of disinfectant could be saved remarkably by cutting down the initial chlorine concentration to the level which guarantees minimum concentration (0.2mg/l) throughout the distribution system.

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Serial Use of Hydrodynamic and Water Quality Model of the Geum River using EFDC-Hydro and WASP7.2 (EFDC-Hydro와 WASP7.2 를 이용한 금강하류의 수리-수질 연계 모델링)

  • Seo, Dongil;Seo, MiJin;Koo, Myungseo;Woo, Jaekyun
    • 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.

Application Load Duration Curve for Evaluation of Impaired Watershed at TMDL Unit Watershed in Korea (수질오염총량 단위유역의 유량조건별 수체 손상 평가를 위한 부하지속곡선 적용성 연구)

  • Hwang, Ha-Sun;Yoon, Chun-Gyeong;Kim, Ji-Tae
    • Journal of Korean Society on Water Environment
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    • v.26 no.6
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    • pp.903-909
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    • 2010
  • The purpose of this study was evaluated on the applicability of Load Duration Curve Method (LDC Method) using HSPF watershed model and sampling data for efficient TMDLs in Korea. The LDC Method was used for assessment pollutant characteristics in watershed and water quality variation in each water flow level. Load Duration Curve is applied for judge the level of impaired water-body and can be estimated the impaired level by pollutant, such as BOD, T-N, and T-P in this study depending on variation of stream flow. As a result, BOD, T-P was usually exceed the standard value at low flow and dry hydrologic period. Improvement of effluent concentration from WWTP and riparian buffer protection zone are effective to improve the water quality. T-N showed the worst condition at mid-range hydrologic period and moist hydrologic period. Therefore, soil erosion control program and BMPs for non-point source pollution control is effective for recovery the water quality, which can be useful method for management of water quality in the plan of recovery water quality spontaneously. Applicability of LDC Method was evaluated in the Nakbon A watershed. However, we need to consider more detailed and accumulated data set such as accurate GIS data and detail pollution data, and WWTP discharge water quality data for accurate evaluation of watershed. Overall, The LDC Method is adequate for evaluation of watersheds characteristics, and its application is recommended for watershed management and TMDL Implementation.

A Study on the Water Quality Prediction in Rural Watershed Using SWAT-WASP Model (SWAT-WASP 모형을 이용한 농촌유역의 수질예측에 관한 연구)

  • 권명준;권순국
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 1999.10c
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    • pp.708-714
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    • 1999
  • For the assessment of the level of stream pollution, SWAT-WASP model linked with GIS was applied to a respresentative rural watershed and evaluated for its applicability through calibration and verfication using observed data. Using daily water yields, sediment yields and nutrient discharge simulated by SWAT model, WASP input file was build. Point source pollutant and water quality change in stream was considered in WASP model. For the model applicatiion , digital maps were constructed for watershed boundary, ladn-use , soil series , digital elevation, and topographic data of Bok-Ha watershed using GRASS. The model application results showed that the simulated runoff was in a good agreement with the observed data and indicated reasonable applicability of the model.

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Performance Comparison of LSTM-Based Groundwater Level Prediction Model Using Savitzky-Golay Filter and Differential Method (Savitzky-Golay 필터와 미분을 활용한 LSTM 기반 지하수 수위 예측 모델의 성능 비교)

  • Keun-San Song;Young-Jin Song
    • Journal of the Semiconductor & Display Technology
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    • v.22 no.3
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    • pp.84-89
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    • 2023
  • In water resource management, data prediction is performed using artificial intelligence, and companies, governments, and institutions continue to attempt to efficiently manage resources through this. LSTM is a model specialized for processing time series data, which can identify data patterns that change over time and has been attempted to predict groundwater level data. However, groundwater level data can cause sen-sor errors, missing values, or outliers, and these problems can degrade the performance of the LSTM model, and there is a need to improve data quality by processing them in the pretreatment stage. Therefore, in pre-dicting groundwater data, we will compare the LSTM model with the MSE and the model after normaliza-tion through distribution, and discuss the important process of analysis and data preprocessing according to the comparison results and changes in the results.

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Application of EFDC Model to an Agricultural Reservoir for Assessing the Effect of Point Source Bypassing (농업용 저수지의 점오염원 바이패스 효과 평가를 위한 EFDC 모델의 적용)

  • Kim, Dong Min;Park, Hyung Seok;Chung, Se Woong
    • Journal of The Korean Society of Agricultural Engineers
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    • v.58 no.6
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    • pp.9-21
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    • 2016
  • Agricultural reservoirs in Korea have been recognized as an emerging resource for recreational and cultural activities for residents. However, most of the reservoirs are eutrophic and showing high level of contamination with nuisance algal bloom and offensive odor during the summer. For better management and restoration of the reservoirs' water quality, scientific modeling approaches could be used to diagnose the problems and evaluate the efficacy of alternative control measures. The objectives of this study were to validate the performance of a three-dimensional (3D) hydrodynamic and water quality model (Environmental Fluid Dynamics Code, EFDC) for a eutrophic agricultural reservoir and assess the effect of bypassing of the effluent from a wastewater treatment plant on the reservoir water quality. The 3D model successfully simulated the temporal variations of water temperature, DO, TOC, nitrogen and phosphorus species and Chl-a observed in 2014 and also captured their spatial heterogeneity in the reservoir. The simulation results indicated that the point source bypassing may reduce the T-N and T-P concentrations of the reservoir by 6.6 ~ 8.2 %, and 1.7 ~ 16.8 %, respectively. The bypassing, however, showed a marginal effect on the control of TOC due to the increased algal biomass associated with the increased water retention time after bypassing as well as the lower TOC level of the effluent compared to the ambient reservoir water.

Valuing the Water Quality Changes in Paldang Watershed: Using New Water Quality Classification Criteria and Indices (새로운 분류체계를 이용한 수질변화의 경제적 가치 추정)

  • Kim, Yong-Joo;Yoo, Young Seong
    • Environmental and Resource Economics Review
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    • v.17 no.4
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    • pp.875-901
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    • 2008
  • This article estimates the economic values of changes in water quality of the Paldang Watershed by using the Choice Experiment (CE). The conditional logit model estimation results show that a small improvement in water quality from the 'status quo' level to the level of 'very good' increases average household's monthly utility by 3,157 Won, whereas a water quality degradation down to the 'normal' level gives rise to an increase in the monthly average utility by 9,649 Won. The corresponding social gain and loss of water quality changes to the Metropolitan Area were thus estimated about 285 billion Won and 872 billion Won, respectively. This article seems meaningful in that it resorts to the new water ecosystem classification criteria and indices that are respondent-friendly. They help a CE study like this to overcome one of its critical weakness that the number and contents of attributes of a CE study can quickly add to the information overload problem, especially where the environmental good under investigation is hard for ordinary respondents to understand.

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