• Proceedings of the Korea Water Resources Association Conference
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• 한국수자원학회 2008년도 학술발표회 논문집
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• pp.1953-1956
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• 2008

본 연구에서는 금강의 하류부의 시간적 공간적 수질변화를 자세하게 분석하기 위하여 3차원 수리동역학 모델인 EFDC 와 비정상상태 수질모델인 WASP 7.2와 를 연계 적용하였다. 본 연구의 대상 구간은 금강하류 부중 대청댐 조절지 방류구 지점부터 공주의 정안천 유입 직전까지 총 48km의 구간이다. 하천의 수심별 수질은 일정하다고 가정하였으나 폭방향의 수질은 좌 중 우로 3개의 소구간으로 나누고 하천의 흐름 방향으로 나누어 전체적으로는 2차원적으로 구분하였다. 하천의 바닥 형상을 이용하여 모델 격자를 구성하였으며 수리모델은 건교부의 수위자료를 이용하여 보정하였고 수질자료는 환경부의 수질측정망 자료를 이용하여 보정하였다. 2차원 수리동역학-수질 연계모델링 결과, 대전 갑천이 유입되고 난 후의 청원지점에서 그리고 청주지역의 영향을 포함하는 미호천이 유입되고 난 연기 지점 그리고 본 연구의 최하류인 공주지점에서는 하천의 폭 방향으로 상당한 수질 차이가 있음을 확인하였다. 이는 대전 갑천 또는 청주 미호천 등이 유입된 이후 효과적으로 혼합되지 않는다는 것을 의미한다. 이는 해당지역의 수질시료 채취 위치에 따라 수질에 현격한 차이가 있을 수 있다는 것을 나타내며, 현재 환경부 수동측정망의 시료채취 방법을 고려하여 볼때 하천수질의 대표성을 나타낼 수 있는가 하는 문제의 차원에서 매우 심각하게 받아들여져야 할 것으로 생각된다. 한편, 현재 우리나라에서 시행되고 있는 오염총량관리제나 대부분의 환경영향평가에서는 하천의 폭 방향의 수질 차이에 대한 고려가 전무하며 이에 대한 전면적인 재검토가 시급하다고 판단된다.

• Journal of the Korean GEO-environmental Society
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• 제22권2호
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• pp.15-23
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• 2021

A method of improving the post-management end system of a landfill that reflected total pollutant load was applied to the SUDOKWON 1st Landfill Site. Modeling results showed that the ratio of remaining methane, when compared to the total maximum potential of 2,521 × 106 Nm3, was estimated to be 8.8% in 2020, 7.0% in 2030, and 6.5% in 2040. If the average oxidation rate of 89.1% in 2005-2019 was applied, the ratio decreased by 1.01% in 2020, 0.76% in 2030, and 0.70% in 2040. This suggests that if the amount of methane generated is all emitted from the surface of the landfill after 2025, the real amount emitted to the atmosphere is less than that in 2019; therefore, the post-management end is possible. According to the results of trend analysis of the quality of leachate water, effluent criteria for Biochemical Oxygen Demand (BOD) can be satisfied in 2024, while those for Chemical Oxygen Demand (COD) and Total Nitrogen (T-N) can be satisfied in 2047 and 2117, respectively. If the post-management end system changed based on total pollutant load, the post-management can be terminated BOD today and COD within a few years; however, the fact that T-N could be terminated only after 2041 shows the need to fundamentally change management methods.

• Journal of Korean Society on Water Environment
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• 제27권5호
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• pp.719-728
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• 2011

The results of investigation on the water quality of the unit watersheds in the Yeongsang/Seomjin River indicate that $BOD_5$, SS, T-P decrease in most of the unit watersheds. However, $COD_{Mn}$ and T-N increase since the Total Maximum Daily Loads (TMDLs). It is thought that $COD_{Mn}$, which is included non-biodegradable matters, is difficult to decrease only using by conventional biological treatment facilities and T-N is affected by non-point source, etc. The results of assessment on 3 years $BOD_5$ indicate that most of the unit watersheds were being improved except Yeongbon A, Seombon C and Yocheon B. In addition, it was found that T-P were also being improved except Yocheon B and Hwangryeong A. Consequently, water qualities of the unit watersheds have been improved in many cases since the TMDLs.

• Journal of Korean Society of Environmental Engineers
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• 제31권9호
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• pp.765-774
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• 2009

Fiber Dyeing and Finishing facility has been recognized as an important pollution source due to its consumption of large volumes of water and chemicals. Unit mass discharge for the conventional water quality parameters such as flowrate, SS, $BOD_5,\;COD_{Mn},\;COD_{Cr}$, TN, TP were estimated. To represent the respective industries, three companies were carefully selected based on its manufacturing goods, flowrate and location at various unit operations and processes. More than 90% of decrease in unit mass estimation between influent and effluent of BOD was observed. But the values themselves were similar to those of Fiber Manufacturing facility due to the high loadings of organic matter. Biodegradability of influent was almost three times higher than that of effluent. Unit mass discharge estimations of unit process (estimated in this study) based on space, products and raw material were similar to those of composite process (estimated by National Institute of Environmental Research), while big difference was observed in the other factors. Unit mass discharge factors calculated in this study can be used as the reference for the estimation of water pollution loading costs in Nakdong river basin. For the effective water pollution control and management, it is essential to characterize the various types of water quality parameters from the effluents of individual industrial wastewater treatment plants.

• Journal of Environmental Science International
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• 제16권5호
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• pp.571-581
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• 2007

The mechanism of water pollution in Lake Shihwa, one of highly eutrophicated artificial lakes in Korea, has been studied using a numerical 3D physical-biochemical coupled model. In this study, the model was applied to estimate the contribution of land-based pollutant load to water quality of heavily polluted Lake Shihwa. The chemical oxygen demand(COD) was adopted as an index of the lake water quality, and the spatial distribution of an average COD concentration during the summer from 1999 to 2000 was simulated by the model. The simulated COD showed a good agreement with the observed data. According to reproducibility of COD, the high-est levels between 8 and 9 mg/L were shown at the inner site of the lake with inflow of many rivers and ditches, while the lowest was found to be about 5 mg/L at the southwestern site near to dike gate. In the pre-diction of water quality of Lake Shihwa, COD showed still higher levels than 3 mg/L in case of reduction of 95% for land-based pollutant load. This suggests that the curtailment of land-based pollutant load is not only sufficient but the improvement of sediment quality or the increase of seawater exchange should be considered together to improve a water quality in Lake Shihwa.

• Proceedings of the Korea Water Resources Association Conference
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• 한국수자원학회 2010년도 학술발표회
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• pp.1258-1262
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• 2010

현재 비점오염원의 정량화를 위하여 정부에서는 지목별 모니터링을 통하여 원단위를 산정하고 있으며, 이를 이용해 수질개선을 위한 수질오염총량관리제를 더욱 효과적으로 운영 평가하기 위한 노력을 하고 있다. 특히, 전 국토의 70% 이상을 차지하고 있는 산림에서 발생되는 유출수에 대한 특성을 파악하는 것이 중요하다. 보통 산림 유출 특성은 모니터링을 수행하여 파악하는 것이 가장 정확한 방법이지만, 지형 작물 시간 강우 패턴 등의 다양한 조건에서 모니터링을 수행하는 것이 어렵다. 또한 지점선정 장비구입 인건비 등 많은 비용이 요구되어 모델링을 통해 시 공간적으로 유출 특성을 평가하고자 하는 연구들이 활발히 진행 중이다. 본 연구는 GIS에서 WEPP 모형의 구동이 가능하게 된 GeoWEPP 모형을 이용하여 활엽수림 침엽수림 혼효림에서 강우시 발생하는 유출량을 모의하여 실측 유출량과의 비교 평가를 통해서 GeoWEPP 모형의 정확성을 평가하는데 있다. 모델 평가를 위해 $R^2$와 Nash-Sutcliffe model Efficiency (NSE)를 사용하였다. 활엽수림 지점은 2009년 총 10개의 강우 발생으로부터 유출량이 산정되었는데, $R^2$와 NSE는 각각 0.98와 0.87로 나타났다. 침엽수림 지점은 14개의 강우 발생시 산정된 유출을 이용하여 모델을 평가하였는데, $R^2$와 NSE가 각각 0.91와 0.90으로 나타났다. 혼효림 지점은 총 10개의 강우 발생시 산정된 유출을 이용하여 모델을 평가한 결과 $R^2$와 NSE가 각각 0.98와 0.94로 나타나 GeoWEPP 모델이 임상별 유출량을 잘 반영하는 것으로 나타났다. 본 연구 결과에서 보이는 바와 같이 GeoWEPP 모형이 임상별 유출특성을 매우 정확하게 예측할 수 있다고 판단된다.

• Proceedings of the Korea Water Resources Association Conference
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• 한국수자원학회 2022년도 학술발표회
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• pp.192-192
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• 2022

하천유량은 기저유량과 직접유량으로 구성되어 있으며 기저유량은 갈수기 하천유량의 대부분을 차지하므로 직접유출과 기저유출의 분리는 중요하다. 또한, T-N, T-P는 기저유출에 영향을 많이 받는 수질 항목으로 기저유출과 직접유출에 의한 오염부하량을 정확히 분석해야한다. 따라서, 기저유출의 오염부하량 산정을 위해 기존의 WAPLE 2의 단점을 개선한 WAPLE 3가 개발되었으며, WAPLE 3는 유량 곡선의 하강부 변곡점에 붙는 특성을 가지고 있는 Baseflow filter program(BFlow) pass 1값을 사용하여 기저유량을 분리해 기저유출 오염부하량을 산정한다. WAPLE 3는 하천유량 중 기저유출을 어느 정도 분리하는지 결정하는 filter parameter 값을 Nathan과 McMahon가 제시한 최적값인 0.925를 사용하였다. 그러나 지형과 강우량 등에 따라 하천 유량에서의 기저유출 비율은 달라지기 때문에 이러한 한계점을 극복하기 위해 WAPLE 4를 개발하였다. WAPLE 4는 filter parameter 값을 사용자가 변경할 수 있게 개발하여 강우에 의한 유량변동 특정이 고려된 기저유량 및 오염부하를 산정하여 결과에 대한 정확도를 높였다. 또한, WAPLE 4는 강우시 오염부하량 산정에 탁월한 Numeric Integration(NI) 방법을 사용하여 직접유량, 기저유량의 오염부하량 및 유량가중평균농도(FWMC) 산정이 가능하도록 하였다. 본 연구의 결과는 오염총량제 및 기저유량 관리를 통한 유량 관련 정책 수립 시 기초자료로 활용될 수 있을 것으로 판단된다.

• Journal of Korea Water Resources Association
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• 제56권11호
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• pp.823-835
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• 2023

Recently, due to the increase in abnormal climate, rainfall intensity is increasing and drought periods are continuing. These environmental changes lead to prolonged drought conditions and difficulties in real-time recognition. In general, drought can be judged by the amount of precipitation and the number of days without rainfall. In determining the impact of drought, it is divided into meteorological drought, agricultural drought, and hydrological drought and evaluation is made using the drought index, but environmental drought evaluation is insufficient. The river water quality managed through the total water pollution cap system is vulnerable to the effects of such drought. In this study, we aim to determine the drought impact on river water quality and quantify the impact of prolonged drought on water quality. The impact of rain-free days and accumulated precipitation on river water quality was quantitatively evaluated. The Load Duration Curve (LDC), which is used to evaluate the water quality of rivers, was used to evaluate water pollution occurring at specific times. It has been observed that when the number of consecutive rainless days exceeds 14 days, the target water quality in the mid-basin is exceeded in over 60% of cases. The cumulative rainfall is set at 28 days as the criteria, with an annual average rainfall of 3%, which is 32.1 mm or less. It has been noted that changes in water quality in rivers occur when there are 14 or more rainless days and the cumulative rainfall over 28 days is 32.1 mm or less in the Gamcheon Mid-basin. Based on the results of this study, it aims to quantify the drought impact and contribute to the development of a drought water quality index for future environmental droughts.

• Journal of Environmental Impact Assessment
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• 제24권5호
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• pp.397-406
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• 2015

The different compliance concentration of effluent limit is applied to effluent discharged from public sewage treatment works(PSTWs) in each watershed on the basis of water quality thereof in accordance with the enforced Watershed Sewer System Maintenance Plan in 2013. It is necessary to set the compliance concentration of effluent limit for PSTWs in watershed sewer system, in order to achieve water quality criteria for regional watersheds or target water quality under TMDL program. Watershed Environmental Agencies establish the Watershed Sewer System Maintenance Plan and set the compliance concentration of effluent limit for PSTWs under the plan. The agencies have a plan to apply strengthened effluent BOD concentration limits for PSTWs in I to IV area grade, respectively. Effluent BOD concentration limits will be strengthened from 5~10 mg/L to 3 mg/L in II~III area grade, from 10 mg/L to 5 mg/L in IV area grade. Uniform application of effluent BOD concentration limits to PSTWs in the watershed sewer system need to be complemented considering type of sewage treatment technology employed and watershed characteristics. Therefore, this study presents assessment methodology which analyze for the compliance concentration of effluent limit to affect water quality of discharge watershed using simulation model for the Jinwee-stream watershed.

• Journal of Korea Water Resources Association
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• 제46권4호
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• pp.345-359
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• 2013

In order to manage water quality efficiently and systematically through TMDL (Total Maximum Daily Load), the demand for the construction of spatial data for stream networks has increased for use with GIS-based water quality modeling, data management and spatial analysis. The objective of this study was to present an improved KRF (Korean Reach File) design as framework data for domestic stream networks to be used for various purposes in relation to the TMDL. In order to achieve this goal, the US EPA's RF (River Reach File) was initially reviewed. The improved design of the graphic and attribute data for the KRF based on the design of the EPA's RF was presented. To verify the results, the KRF was created for the Han River Basin. In total, 2,047 stream reaches were divided and the relevant nodes were generated at 2,048 points in the study area. The unique identifiers for each spatial object were input into the KRF without redundancy. This approach can serve as a means of linking the KRF with related database. Also, the enhanced topological information was included as attributes of the KRF. Therefore, the KRF can be used in conjunction with various types of network analysis. The utilization of KRF for water quality modeling, data management and spatial analysis as they pertain to the applicability of the TMDL should be conducted.