• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2001.10a
• /
• pp.203-206
• /
• 2001

Finding the optimal solution in the river water quality management system is very hard with the non-linearity of the water quality model. Many suggested methods for that using the linear programming, non-linear programming and dynamic programming, are failed to give an optimal solution of sufficient accuracy and satisfaction. We studied a method to find a solution optimizing the river water quality management in the aspect of the efficiency and the cost of the waste water treatment facilities satisfying the water Quality goals. In the suggested method, we use the QUAL2E water quality model and the genetic algorithm. A brief result of the project to optimize the water quality management in the Youngsan river is presented.

• Journal of Korean Society on Water Environment
• /
• v.31 no.5
• /
• pp.569-575
• /
• 2015

The current Total Pollution Load Control (TPLC) sets the Target Water Quality (TWQ) by utilizing the delivery ratio, unit loads, and water quality modeling, it also allocates the watershed's permitted discharge load. Currently, common target pollutants of every unit watershed in TPLC are BOD and T-P. This study has reviewed the 1th and 2th of TWQ setting process for the Nakdong River 3th TWQ setting in Total Pollution Load Control (TPLC). As a result of review, 1th and 2th were divided into one management basin (mulgeum) for setting management goals. However, 3th was divided into six management basins (mulgeum, gnagjeong, geumho river, nam river, miryang river, end of nakdong river). The principle of management goal setting were to achieve the objective criteria of Medium Areas for the linkage of the water environment management policy. And Anti-Degredation (principle of preventing deterioration) were applied to the 3th TWQ. Also, additional indicators were considered in accordance with the reduction scenarios for the final management goals.

• Journal of Korean Society on Water Environment
• /
• v.28 no.3
• /
• pp.426-435
• /
• 2012

The variation of stream flow is the one of the most important factors which influence on that of water quality in the unit watershed. The target water quality goal is established and permissible load is allotted in the base of the standard flow condition along with its water quality for the management of Total Maximum Daily Loads (TMDLs). A standard flow selected could cause problems in the load allotment if it was not properly arranged. This study reviewed the acquisition of water quality data, the self-variation and the retainability in water quality on the specific flow conditions. This study also proposed the median and the adjusted average flow condition out of general flow conditions as alternative standard flow conditions. It is considered that the alternatives can make the water quality data easily acquired and the water quality representativeness more enhanced on the standard flow conditions.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2004.05b
• /
• pp.1400-1403
• /
• 2004

The current industrial development and the Increase of population along Nakdong River have produced a rapid Increase of wastewater discharge. This has resulted in problem of water quality control and management. Although many efforts have been carried out, water quality has not significantly improved. The goal of this study is to design a NGIS-based water quality management system for the scientific water quality control and management in the Nakdong River. For general water quality analysis, QULA2E model was applied to the Nakdong River. A sensitivity analysis was made to determine significant parameters and an optimization was made to estimate optimal values. The calibration and verification were performed by using observed water quality data for Nakdong River. A water qualify management system for Nakdong River was made by connecting the QUAL2E model to ArcView. It allows a Windows-based Graphic User Interface(GUI) to implement all operation with regard to water quality analysis. The modeling system in this study will be an efficient NGIS for planning of water quality management.

• Journal of Korean Society on Water Environment
• /
• v.29 no.1
• /
• pp.66-73
• /
• 2013

Total Maximum Daily Loads (TMDLs) system was introduced to manage pollution load of watershed and to improve water quality of unit watershed so that it is possible to protect dringking water soureces. Load allocation observation is the most important factor in TMDLs system. Because if load allocation is not observed, it is difficult to achieve water quality goal of unit watershed. Also it is impossible to improve water quality of the drinking water sources. Therefore it is necessary to apply some kind of sanctions (penalty) in case of excess of load allocation. The sanctions have to be, however, applied differently based on various reduction plan types, i.e., using the reduction load planed in 2nd phase, delay the completion, additional reduction in 2nd phase, error of the pollution sources, etc. Moreover, the penalty load should be properly imposed, lest it should be overburden the provence. The reduction load trade inter province must be restrictively permmitted only the same unit watershed.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.46 no.1
• /
• pp.99-105
• /
• 2004

The present agricultural water quality standards are set by a policy goal. This is intended for water quality management of public water resources, but not for the use of water resources. These standards were not determined by considering the influence of water quality on the safety of agricultural produce and the growth, yield and quality of agricultural crops. Thus, this study was carried out to investigate the influence of irrigation water quality on the growth, yield, and grain quality of rice and acquire fundamental knowledges to set up irrigation water quality standards. The pot experiment was conducted with 4 treatments using irrigation waters with various total nitrogen concentrations (control, 1, 5, 10, 20mg/L) and replicated four times with randomized block design. The results of this study showed that plant height, number of tiller, plant dry weight, the uptake of N, P, and K, and rice protein contents tended to increase as the T-N concentration in irrigation water was increased. In addition, grain yield at T-N 20 mg/L was significantly higher than in the control, but the percentage of head rice was slightly lower due to the increase of green kernel and white belly/core kernel.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.31 no.6B
• /
• pp.541-550
• /
• 2011

This study sets the goal to improve effectively water quality of stream by complementing the weak points of the gravel contact oxidation process to use the inverted siphon curved channel system in free overfall of serial contact materials. The size of the current system can be diminished by expanding contact time, and the materials' replacement can be made easier when their gap are closed through the filtering boxes of contact materials. This system also has been developed into a construction method in which mixed and serial contact materials can be employed by using just the conventional single contact materials. It was verified the improvement ability of water quality of this system, during the simulation test at Tandong stream in Daejeon. The results of the verification of water quality improvement through several experiments in field were measured as follows : it showed to reduce about the averaged 55~83% higher than 60~75%, the internal planned goal of water quality improvement facilities.

• Journal of Korea Water Resources Association
• /
• v.35 no.2
• /
• pp.137-148
• /
• 2002

The purpose of this study was to examine the effect of water quality improvement due to dredging the bottom deposit at the downstream of a urban river. The finite difference method was used to analyze the water quality variations caused by the depths of dredging and intercepting ratios of the goal years. 21 boring points were selected along the 11.2km river reach running through a metropolitan city. The pollution levels of the deposits from the bored Points were examined by the leaching test. The improvement effect of the water quality, measured as changes of COD, were carried at under drought, minimal, and normal flow. The result indicates that the dredging of the contaminated sludge contributes the improvement of the water quality.

• Journal of Korean Society on Water Environment
• /
• v.26 no.2
• /
• pp.279-288
• /
• 2010

The water quality variations or changes are closely relevant to the characteristics of unit watersheds and have an effect on the attainment of their water quality goal. This study was conducted to analyze the water quality distribution and its change patterns of unit watersheds in Nakdong river basin. It revealed that 25 unit watersheds out of 41 showed the normality in water quality. Most of unit watersheds had a considerable variation in water quality, especially in the season of spring and summer but a little in terms of flow rate. Annual relative differences in water quality ranged from 13.0 to 26.6% with the maximum of 75%. 28 unit watersheds (62%) had the tendency to decrease in water quality as the flow rate increased while 13 (38%) to increase. The extension of standard flow led to considerable differences in water quality depending on its ranges, which meant uncertainties might be included in the process of TMDL development. It is suggested that annual average flow rate should be chosen as a standard flow in the area where the water quality change has little relation to the flow rate.

• Journal of Environmental Health Sciences
• /
• v.28 no.2
• /
• pp.61-69
• /
• 2002

Oship stream is located nearby south eastern coasts. This study was performed to find out waters quality modeling and then to predict water quality of Oship stream. Based on survey data, BOD, T-N, T-P calibration and verification result were in good agreement with measured value within mean coefficient variance(MSE) value, which were 13.9%, 9.0%, 26.5% and 19.5%, 12.0%, 16.5%, respectively. Sectional water quality predictions of the main stream of Oship stream are executed on the basis of the following cases 1) with sewage treatment of Dogye-eup 2) reduction of mine wastewater treatment of 80% in th basin. As a result, BOD, T-P improvement rates at down stream of Oship stream, case 1) were appeared 12.2%, 22.2%, case 2) maximum sulfate ion and conductivity reduction removal rate of Oship stream were 58%, 68%. The main pollution sources of Oship-stream were almost domestic wastewater and mine wastewater discharged from Dogye-eup which located in uppers stream. The large effects will appear after the construction of Dogye sewage water treatment plant which remove the organic matter and nutrients in these sewage water. The waste water from mine can not easily to treat for characteristics of effluence and economic problems. However, to achieve the goal of water quality in Oship-stream water system, treatments of those are necessary.