• Journal of Korean Society on Water Environment
• /
• v.23 no.4
• /
• pp.561-567
• /
• 2007

It is necessary to predict future water pollution sources in the establishment of Total Maximum Daily Load (TMDL) plan for watershed management. There are some difficulties and limits in estimating the pollution sources accurately since the prediction method is not firmly established. This study reviewed the existing methods of prediction and developed a technique characteristics. The characteristics were obtained by analyzing the change pattern of pollution sources by region and incorporated in the technique. A distinctive feature of the technique is to eliminate the influences of land use change included in the pollution source data of a region. The technique has been applied and tested. The test result showed the improvement on the prediction accuracy. A computer program was also developed for the easy application of the technique.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.44 no.5
• /
• pp.96-105
• /
• 2002

As an useful water purification system for non-point source pollution in rural watersheds, interests in constructed wetlands are growing at home and abroad. It is well known that constructed wetlands are easily installed, no special managemental needs, and more flexible at fluctuating influent loads. They have a capacity for purification against nutrient materials such as phosphorus and nitrogen causing eutrophication of lentic water bodies. The Constructed Wetland Design Model (CWDM), developed through this study is consisted mainly of Database System, Runoff-discharge Prediction Submodel, Water Quality Prediction Submodel, and Area Assessment Submodel. The Database System includes data of watershed, discharge, water quality, pollution source, and design factors for the constructed wetland. It supplies data when predicting water quality and calculating the required areas of constructed wetlands. For the assessment of design flow, the GWLF (Generalized Watershed Loading Function) is used, and for water quality prediction in streams estimating influent pollutant load, Water Quality Prediction Submodel, that is a submodel of DSS-WQMRA model developed by previous works is amended. The calculation of the required areas of constructed wetlands is achieved using effluent target concentrations and area calculation equations that developed from the monitoring results in the United States. The CWDM is applied to Bokha watershed to appraise its application by assessing design flow and predicting water quality. Its application is performed through two calculations: one is to achieve each target effluent concentrations of BOD, SS, T-N and T-P, the other is to achieve overall target effluent concentrations. To prove the validity of the model, a comparison of unit removal rates between the calculated one from this study and the monitoring result from existing wetlands in Korea, Japan and United States was made. As a result, the CWDM could be very useful design tool for the constructed wetland in rural watersheds and for the non-point source pollution management.

• Journal of Environmental Impact Assessment
• /
• v.23 no.3
• /
• pp.177-186
• /
• 2014

Depending on the change of lifestyle and the improvement of people's living standards and rapid industrialization, urbanization of recent, demand for water is increasing rapidly. So emissions of domestic wastewater and various industrial waste water has increased, and water quality is worsening day by day. Therefore, in order to provide a measure against the occurrence of water pollution accident, this study was tried to simulate water pollution accident. This study simulated 2008 Gimcheon phenol accident using 1,2-D model, and analyze scenario for prevent of water pollution accident. Consequently the developed 1-D model presents high reappearance when compared with 2-D model, and has been able to obtain results in a short simulation run time. This study will contribute to the water pollution incident response prediction system and water quality analysis in the future.

• Journal of the Korean Society of Safety
• /
• v.27 no.5
• /
• pp.135-140
• /
• 2012

In this study, the behavior of pollutant was calculated at Paldang reservior according to several scenarios of the accidental water pollution by means of the numerical models for forecasting water quality. Also managemental plans for situation of the accidental water pollution happening at Paldang watershed were simulated. According to the simulating results, a plan of increase of discharge at Cheongpyeong dam reduced the peak concentration of pollutants, whereas extended the time for stopping water intake. Another plan, drop of water elevation at Paldang dam, decreased seriously the time for stopping water intake although there were a little effect to decrease the peak concentration. Thus it was concluded that appropriate combinations of the plans for the increase discharge and the dropping water elevation should be used to deal with the accidental water pollution at Paldang watershed.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.47 no.4
• /
• pp.65-74
• /
• 2005

AnnAGNPS model was applied to a catchment mainly occupied with bushland for modeling non-point source pollution. Since the single event model cannot handle events longer than 24 hours duration, the event-based calibration was carried out using the continuous mode. As event flows affect sediment and nutrient generation and transport, the calibration of the model was performed in three steps: Hydrologic, Sediment and Nutrient calibrations. The results from hydrologic calibration for the catchment indicate a good prediction of the model with average ARE(Absolute Relative Error) of $24.6\%$ fur the runoff volume and $12\%$ for the peak flow. For the sediment calibration, the average ARE was $198.8\%$ indicating acceptable model performance for the sediment prediction. The predicted TN(Total Nitrogen) and TP(Total Phosphorus) were also found to be acceptable as the average ARE for TN and TP were $175.5\%\;and\;126.5\%$, respectively. The AnnAGNPS model was therefore approved to be appropriate to model non-point source pollution in bushland catchments. In general, the model was likely to result in underestimation for the larger events and overestimation fur the smaller events for the water quality predictions. It was also observed that the large errors in the hydrologic prediction also produced high errors in sediment and nutrient prediction. This was probably due to error propagation in which the error in the hydrologic prediction influenced the generation of error in the water quality prediction. Accurate hydrologic calibration should be hence obtained for a reliable water quality prediction.

• Korean Journal of Agricultural Science
• /
• v.46 no.1
• /
• pp.67-78
• /
• 2019

The purpose of this study was to predict the water quality using the RNN (recurrent neutral network) and LSTM (long short-term memory). These are advanced forms of machine learning algorithms that are better suited for time series learning compared to artificial neural networks; however, they have not been investigated before for water quality prediction. Three water quality indexes, the BOD (biochemical oxygen demand), COD (chemical oxygen demand), and SS (suspended solids) are predicted by the RNN and LSTM. TensorFlow, an open source library developed by Google, was used to implement the machine learning algorithm. The Okcheon observation point in the Geum River basin in the Republic of Korea was selected as the target point for the prediction of the water quality. Ten years of daily observed meteorological (daily temperature and daily wind speed) and hydrological (water level and flow discharge) data were used as the inputs, and irregularly observed water quality (BOD, COD, and SS) data were used as the learning materials. The irregularly observed water quality data were converted into daily data with the linear interpolation method. The water quality after one day was predicted by the machine learning algorithm, and it was found that a water quality prediction is possible with high accuracy compared to existing physical modeling results in the prediction of the BOD, COD, and SS, which are very non-linear. The sequence length and iteration were changed to compare the performances of the algorithms.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2000.10a
• /
• pp.578-583
• /
• 2000

In order to operate water quality model for a lake or a channel, user should examine the all kinds of parameters and should know how them react to the model for calculating the pollution which are happened from the watershed or are reacted in the water. The aim of this study is analyzing the characteristics of parameters which are used by a water quality model (CE-QUAL-W2), so that we are trying to find out how them to react to the model for calculating the many kinds of pollution.

• Journal of Korean Society on Water Environment
• /
• v.25 no.4
• /
• pp.481-493
• /
• 2009

This study was conducted to performance appraisal of Total Maximum Daily Loads (TMDLs), especially in terms of performance on development & reduction plan and water quality status of unit watershed. Because load allocations for pollution sources were predicted redundantly by uncertainty of prediction, TMDLs master plan has been frequently changed to acquire load allocation for local development. Therefore, It need to be developed more resonable prediction techniques of water pollution sources to preventing the frequent change. It is suggested that the reduction amount have to be distributed properly during the planning period. In other words, it has not to be concentrated on the specific year (especially final year of the planning period). The reason why, if the reduction amount concentrate on the final year of the planning period, allotment loading amount could not be achieved in some cases (e.g., insufficiency of budget, extension of construction duration). If the development plan was developed including uncertain developments, it is necessary to be developed reduction plan considered with them. However, some of the plans in the reduction plan could not be accomplished in some case. Because, it is not considered financial abilities of local governments. Consequently, development plan must be accomplished to avoid uncertain developments, and to consider financial assistance to support the implementation of effective plan. Water quality has been improved in many unit watersheds due to the TMDLs, especially in geum river and yeongsang/seomjin river.

• Journal of the Korea Society of Computer and Information
• /
• v.21 no.8
• /
• pp.57-64
• /
• 2016

Initial prevention activities and rapid propagation conditions is the most important to prevent diffusion of water pollution. If water pollutants flow into streams river or main stresm located in environmental conservation area or water intake facilities, we must predict immediately arrival time and the diffusion concentration to the proactive. National Institute of Environmental Research developed water pollution incident response prediction system linking dam and movable weir. the system is mathematical model which is updated daily. Therefore it can quickly predict the arrival time and the diffusion concentration when there are accident of oil spills and hazardous chemicals. Also we equipped with mathematical model and toxicity model of EFDC(Environmental Fluid Dynamics Code) to calculate the arrival time and the diffusion concentration. However these systems offer the services of an offline manner than real-time control services. we have ensured the reliability of data collection and have developed a real-time water quality measurement data transmission device by using the data linkage utilizing a mode bus communication and a commercial SCADA system, in particular, we implemented to be able to do real-time water quality prediction through information infrastructure of the water quality integrated management business created by utilizing the construction of the real-time prediction system that utilizes the data collected, the Open map, the visual representation using charts API and development of integrated management system development based on web maps.

• Journal of Ocean Engineering and Technology
• /
• v.20 no.1 s.68
• /
• pp.55-62
• /
• 2006

Recently, pollution by development in coastal areas is going from bad to worse. The Korean government is attempting to make policies that prevent water pollution, but it is still difficult to say whether such measures are lowering pollution to an acceptable level. More specifically, the general investigation that has been done in KOREA does not accurately reflect the actual conditions of pollution in coastal areas. An investigation that quantitatively assesses water quality management using rational prediction technology must be attempted, and the ecosystem model, which incorporates both the 3-dimensional hydrodynamic and material cycle models, is the only one with a broad enough scope to obtain accurate results. The hydrodynamic model, which includes advection and diffusion, accounts for the ever-changing flow and (quality) of water in coastal areas, while the material cycle model accounts for pollutants and components of decomposition as sources of the carbon, phosphorus, and nitrogen cycles. In this paper, we simulated the rates of dissolved oxygen (DO), chemical oxygen demand (COD), total nitrogen(T-N) and total-phosphorous(T-P) in Korea's Ulsan Area. Using the ecosystem model, we did simulations using a specific set of parameters and did comparative analysis to determine those most appropriate for the actual environmental characteristics of Ulsan Area. The simulation was successful, making it now possible to predict the likelihood of coastal construction projects causing ecological damage, such as eutrophication and red tide. Our model can also be used in the environmental impact assessment (EIA) of future development projects in the ocean.