• Journal of Environmental Health Sciences
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• v.32 no.5 s.92
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• pp.424-430
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• 2006

Since 1985, the Gangwon Institute of Health and Environment(GIHE) and Ministry of Environment have collected rivers and streams water quality data in an ambient surface water monitering program. This study was prepared to propose an achievement of water quality of rivers subject to management by area according to an created level while establishing a water quality level applicable to the Gangwon area. As a result of evaluating correlativity on the BOD-based water quality data, BOD versus TP, and TP versus SS demonstrated significance at a confidence level of 95%. Evaluating correlativity on $10{\sim}90$ percentile values of analyzed data, a coefficient of determination, $r^{2}$ of BOD versus TP, and TP versus SS were 0.625, 0.286 respectively. Grading the results by evaluation method, the representative values of TP were 0.030 mg/l for I level, 0.100 mg/l for II level, 0.200 mg/l for Ill level, 0.300 mg/l for IV level, and 0.350 mg/l for V level, and those of SS were indicated 4.0 mg/l for I level, 15.0 mg/l for II level, 30.0 mg/l for III level, 45.0 mg/l for IV level, and 60.0 mg/l for V level. As for the limiting factor allowing the water quality standard exceeded, BOD posted 61% as the factor was found in 11 places, TP 28%, and SS 33%.

• Journal of Korean Society on Water Environment
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• v.36 no.6
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• pp.521-534
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• 2020

In this study, the variation of water quality was analyzed for six sites in major tributaries of the Nakdong River Basin. Standard-FDC (Flow Duration Curve) was developed using PM (Percentile Method), one of the statistical FDC estimation methods. The LDC (Load Duration Curve) was obtained using the developed FDC. The current method and the LDC evaluation method were compared and analyzed to evaluate the achievement of TWQ (Target Water Quality). Regarding the monthly flow rate variation, the five sites showed the distribution of the lowest flow rate between May and June, indicating a high probability of dry weathering of the streams. The variation of water quality confirmed the vulnerable timing of flow rate in each site, and it is therefore deemed necessary to plan to reduce T-P and TOC. A comparison and evaluation of TWQ showed that there was a difference between the TWQ values achieved by the two techniques. In addition, the margin ratio to the 50% excess ratio can be found in the LDC evaluation. The results of the LDC evaluation by section and by month showed whether or not the water quality was exceeded by flow conditions, along with the vulnerable sections and timing. Accordingly, it is judged that this method can be used for water quality management in TMDLs (Total Maximum Daily Loads).

• Journal of The Korean Society of Agricultural Engineers
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• v.58 no.4
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• pp.67-74
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• 2016

Load Duration Curve (LDC) can be used as a method for load management of point and non-point pollution source because the LDC easily assesses the water quality corresponding to hydrological changes in a watershed. Recently, the application of LDC to total pollution load management is a growing interest in Korea. In this regard, A desktop-based LDC assessment system was developed in this study to provide convenience to users in water quality evaluation. The developed system can simply produce the LDC by using streamflow and water quality data involved in its database. Also, The system can quantitatively inform the success or failure of the achievement for a target water quality at monthly scale. Furthermore, seasonal water quality and point/non-point pollution load in a watershed can be estimated by this system. We expect that the developed system will contribute to establish local and national policies regarding water management and total pollution load management because of its advantages such as the pollution tracking investigation and the analysis of water quality and pollution loading amount in an ungauged watershed.

• Journal of Environmental Impact Assessment
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• v.33 no.5
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• pp.228-251
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• 2024

It is clear that the implementation of Total Pollution Load Management (TPLM) has contributed to the improvement of river water quality in Korea. However, it is also true that the TPLM has focused on point source pollution management, with limitations in addressing non-point source pollution. This study examined the issues of the current TPLM from the perspective of non-point source pollution, which is closely related to high-flow conditions, by analyzing Load Duration Curves (LDC) using water quality and flow data collected over the past four years from 21 sub-watersheds in the Geum River Basin. Since the current TPLM is based on water quality predictions using a static water body model that applies the average flow of the dry season, we found that the reduction in loads required under actual flow conditions could be up to 140 times greater than under the reference flow condition, indicating that load amounts under high-flow conditions are not reflected. Additionally, there were abnormal correlations between discharge loads and water quality in several sub-watersheds, and illogical situations arose where compliance with allocated loads did not align with achieving the target water quality. While the causes of such abnormal and illogical situations are diverse and complex, this study highlights the need for rational reflection of non-point source loads under high-flow conditions in water quality modeling. As a solution, we propose the application of watershed models and dynamic water body models.

• Journal of Korean Society on Water Environment
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• v.31 no.3
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• pp.295-303
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• 2015

In Korea, Total Maximum Daily Loads(TMDLs) has been enforced to restore and manage water quality in the watersheds. However, some assesment of implementation plan of TMDLs showed that the achievement of the target water quality is not related to the proper allocation loads because difference of flow duration interval. In the United States, the discharge loads are determined by water quality modeling considering standard flow conditions according to purpose. Therefore, this study tried to develop the allocation method considering economical efficiency using water quality model. For this purpose, several allocation methods being used in the management of TMDLs is investigated and develope an allocation criteria considering regional equality and uniformity. Since WARMF(Watershed Analysis Risk Management Framework) model can simulate the time varying behavior of a system and the various water quality variables, it was selected for a decision support system in this study. This model showed fairly good performance by adequately simulating observed discharge and water quality in Miho watershed. Furthermore, the scenario simulation results showed that the effect of annual average water quality improvement to remove 1kg BOD is more than 25 times, even if point pollutants treatment facility is six times more expensive to operate than non-point pollutants treatment facility.

• Journal of Korean Society on Water Environment
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• v.25 no.3
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• pp.425-431
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• 2009

It is very important to know the probability distribution of water-quality constituents for water-quality control and management of rivers and reservoirs effectively. The probability distribution of BOD in Anseong Stream was analyzed in this paper using Kolmogorov-Smirnov test which is widely used goodness-of-fit method. It was known that the distribution of BOD in Anseong Stream is closer to Log-normal, Gamma and Weibull distributions than Normal distribution. Normal distribution can be partially applied depending on significance level, but Log-normal, Gamma and Weibull distributions can be used in any significance level. Also the estimated Log-normal distribution of BOD at Jinwi3 station was to be compared with the measured in 2001, 2002 and 2003 years. It was revealed that the estimated probability distribution of BOD at Jinwi3 follows a theoretical distribution very well. The applicable probability distribution of BOD can be used to explain more rigorously and scientifically the achievement or violation of target concentration in TMDL(Total Maximum Daily Load).

• Journal of Korea Water Resources Association
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• v.54 no.10
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• pp.769-777
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• 2021

This study investigated the change of the achievement rate of the target water quality conditioned on the occurrence of severe drought, to assess the effects of meteorological drought on the water quality management in the Nakdong River basin. Using three drought indices with difference time scales such as 30-, 60-, 90-day, i.e., SPI30, SPI60, SPI90, and three water quality indicators such as biochemical oxygen demand (BOD), total organic carbon (TOC), and total phosphorus (T-P), we first analyzed the relationship between severe drought occurrence water quality change in mid-sized watersheds, and identified the watersheds in which water quality was highly affected by severe drought. The Bayesian network models were constructed for the watersheds to probabilistically assess the relationship between severe drought and water quality management. Among 22 mid-sized watersheds in the Nakdong River basin, four watersheds, such as #2005, #2018, #2021, and #2022, had high environmental vulnerability to severe drought. In addition, severe drought affected spring and fall water quality in the watershed #2021, summer water quality in the #2005, and winter water quality in the #2022. The causal relationship between drought and water quality management is usufaul in proactive drought management.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.523-527
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• 2017

우리나라의 수질오염총량관리제는 지역의 발전 계획과 하천의 수질을 연계시켜 목표수질을 달성하는 범위 내에서 개발을 허용한다는 것을 기본으로 하여 1999년 "한강수계상수원수질개선및주민지원등에관한법률"에 의해 처음 시행되었다. 그러나 한강수계보다 늦게 2004년에 도입된 낙동강, 금강, 영산강 섬진강 수계에서는 의무제 총량으로 우리나라에서 처음 도입되어 지난 12년간 시행되었으며 충청북도와 강원도를 제외한 한강수계에서도 2013년 6월부터 의무제 총량이 도입되었다. 1단계 수질오염총량관리제는 BOD만을 관리항목으로 설정하여 관리한 반면 2011년부터 2015년까지 시행하는 2단계 수질오염총량관리제는 부영양화 방지를 위해 총인항목을 포함하여 관리항목을 설정하여 관리하였으며, 2016년에 시작하여 2020년까지 시행하는 3단계수질오염총량관리제는 2단계에서와 같은 관리항목을 설정하여 시행하고 있다. 본 연구에서는 3단계 영산강수계의 수질오염총량관리제 목표수질의 달성전망을 평가하기 위하여 3단계 기본계획에서 활용한 QUAL-MEV 모델을 이용하였으며, 2012년 수질자료를 보정자료로, 2015년 수질자료를 검증자료로 활용하여 구축하고 2020년의 영산강수계 8개 단위유역의 말단지점에 대하여 목표수질의 달성을 평가하였다. 그 결과 BOD는 영본A, 영본B지점에서 각각 목표수질을 21%, 8%를 초과하며 T-P는 영본A지점에서 30%를 초과하여 목표수질을 달성하지 못할 것으로 예측되었다. 영산강수계 3단계 수질오염총량관리제의 성공을 위하여 영본A, 영본B지점의 목표수질 달성을 위한 추가 수질개선계획의 수립이 필요한 것으로 판단된다.