• Magazine of the Korean Society of Agricultural Engineers
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• v.38 no.3
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• pp.92-100
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• 1996

In order to control the water quality in rivers or lakes, it is needed to evaluate accurate amount of pollutant loadings from watersheds. The daily pollutant loadings were simulated using the pollutant loading calculation model which was composed of mathematical equations superimposed on the TANK model. The calibration of runoff and pollutant loading parameters were carried out with observed data, using a trial-and-error method. In addition, the proposed model was applied to evaluate its applicability for the representative watershed, the Bokha river watershed, Icheon city, Korea. The parameters of SS and T-P showed large values in the first tank while T-N showed large in the second tank. As a result of simulating the daily pollutant loadings by the pollutant loading calculation model, all of SS, T-N and T-P loadings were increased or decreased according to the amount of runoff discharge. Especially, it was apparent that SS and T-P loadings were significantly influenced by the runoff variation when it was rain. These results could partly explain that SS and T-P would occur mainly from the surface runoff while T-N would occur from both surface and subsurface flow.

• Journal of Environmental Science International
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• v.29 no.5
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• pp.531-539
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• 2020

To understand the composition, quantity, and quality of Suspended Particulate Organic Matter (SPOM) in the Gangneung Namdae Stream, Korea, we examined spatiotemporal variations in water temperature, salinity, chlorophlly a (Chl a), Particulate Organic Carbon (POC) and nitrogen (PON), and carbon stable isotope (δ¹³C) of SPOM at six stations in June (pre-monsoon), July (monsoon), and September (post-monsoon) 2017. With increasing precipitation, the average POC and C/N values increased significantly in July than in June. In September, the values decreased with decreasing precipitation. The δ¹³C values showed irregular spatiotemporal fluctuations among the stations and periods, thereby suggesting a greater contribution of autochthonous organic matter to the pool of SPOM than that of allochthonous organic matter derived from upstream. In addition, the large and irregular changes in POC, C/N ratio, C:Chl a, and δ¹³C compared to that of PON were observed for all periods among the stations, indicating a serial discontinuity of the stream. Our results suggest that the Gangneung Namdae Stream is significantly influenced by the increase in freshwater discharge caused by heavy rainfalls during the summer monsoon and post-monsoon periods.

• Smart Structures and Systems
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• v.26 no.6
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• pp.781-796
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• 2020

Prediction of total sediment load is essential in an extensive range of problems such as the design of the dead volume of dams, design of stable channels, sediment transport in the rivers, calculation of bridge piers degradation, prediction of sand and gravel mining effects on river-bed equilibrium, determination of the environmental impacts and dredging necessities. This paper is aimed to investigate and predict the total sediment load of the Wadi Arbaat in Eastern Sudan. The study was estimated the sediment load by separate total sediment load into bedload and Suspended Load (SL), independently. Although the sediment records are not sufficient to construct the discharge-sediment yield relationship and Sediment Rating Curve (SRC), the total sediment loads were predicted based on the discharge and Suspended Sediment Concentration (SSC). The turbidity data NTU in water quality has been used for prediction of the SSC in the estimation of suspended Sediment Yield (SY) transport of Wadi Arbaat. The sediment curves can be used for the estimation of the suspended SYs from the watershed area. The amount of information available for Khor Arbaat case study on sediment is poor data. However, the total sediment load is essential for the optimal control of the sediment transport on Khor Arbaat sediment and the protection of the dams on the upper gate area. The results show that the proposed model is found to be considered adequate to predict the total sediment load.

• Journal of Species Research
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• v.13 no.3
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• pp.332-339
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• 2024

The filamentous freshwater red alga Compsopogon caeruleus(Compsopogonophyceae, Compsopogonaceae, Rhodophyta) occurs in tropical and subtropical regions of worldwide. This species has been reported from Asia, America, Africa, Europe and Oceania, and the worldwide distribution of Compsopogon caeruleus is in variable water habitats. Several morphospecies of the genus Compsopogon had been recorded, but recent molecular phylogenetic analyses with worldwide sampling identified a monospecific genus, C. caeruleus. In the present study, we first report a freshwater red alga Compsopogon caeruleus from Korea. We identified Compsopogon caeruleus in an urban river in Yongin City, and analyzed its morphological and genetic characteristics. Nuclear 18S rDNA, plastidal rbcL gene and mitochondrial cox1 gene sequences isolated from Korean Compsopogon caeruleus showed high sequences similarity with Compsopogon caeruleus from worldwide (98.6-100% (18S rDNA), 99-100% (rbcL) and 97.7-100% (cox1)). These sequences similarities support the identification of a red alga found in Korea as Compsopogon caeruleus. This new geographical report provides the useful information for understanding the distribution and habitat range of Compsopogon caeruleus especially concerning urban freshwater environments.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.10
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• pp.551-557
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• 2015

This study analyzes potentially hazardous sub-watersheds from non-point source pollution areas using an HSPF model. The watershed of the Juam dam reservoir was divided into 29 sub-watersheds, and the flow, BOD, TN and TP concentration for the Juam dam watershed were evaluated from 2009 to 2012 using a watershed model, with a warming period from 2009 to 2010. The results of the watershed model agreed well with the flow and water quality field measurements. The calculated average non-point source loadings were BOD of 8.8 and $9.1kg/day/km^2$ in 2011 and 2012, respectively; TN of 9.7 and $10.1kg/day/km^2$ in 2011 and 2012, respectively; and TP of 0.30 and $0.33kg/day/km^2$ in 2011 and 2012, respectively. The non-point source loading of the Bonghwa stream watershed was calculated, and predominantly assessed upstream of the Boseong river. Additionally, the Miryeok, Jangpyeong, Yuleo, Guam, Seokgyo, Mundeok, Incheon, and Bongnae stream watersheds, with extensive agricultural areas, were assessed to be potentially hazardous areas in terms of non-point source management. In this study, HSPF model was applied in order to aid in the selection of non-point source reduction facilities for the Juam dam watershed, where they were evaluated as to whether they would be applicable for non-point source management.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.545-545
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• 2015

금호강은 포항시 북구 죽장면에서 발원하여 낙동강으로 합류하는 낙동강 제1지류로 유로연장은 114.6km이며, 영천과 경산지역의 생활 및 공업용수, 대구지역의 공업용수로 사용된다. 금호강의 평균 BOD는 1983년 191.2mg/L로 하수도나 산업폐수 처리 전 원수 정도의 수준이었으나, 2014년에는 3.6mg/L로 낮아져 수질개선율이 98.1%를 나타냈다. 이를 위해서 하 폐수 처리장 건설과 아울러 포항철강산업단지의 공업용수 공급을 위한 영천댐에 임하댐과 도수터널 52km를 연결하여 2001년부터 금호강에 하천유지용수로 $3.463m^3/s$를 공급하였다. 금호강 유역에서 오염총량제 목표수질은 금호B 지점이 BOD 3.8mg/L, TP 0.236mg/L이며, 금호C 지점은 BOD 4.0mg/L, TP 0.254mg/L이다. 분석기간인 2013년에서 2014년의 평균 수질은 모두 기준을 만족하고 있으나, 수질악화시에 금호B 지점에서 최대 BOD 8.6mg/L, TP 0.511mg/L, 금호C 지점에서 최대 BOD 8.5mg/L, TP 0.449mg/L을 나타내었다. 이에 영천댐의 탄력적인 유량방류로 수질악화시에 추가 방류를 수행하여 수질을 안정화시키고, 물공급의 안정화가 필요한 상황이다. 본 연구에서는 갈수기 및 이수기에 영천댐에서 하천유지용수보다 많은 유량을 탄력적으로 방류하는 가상조건을 설정하여, 하천유지유량과 목표수질을 만족하는 유량분석을 수행하였다. 이를 위해 QUALKO2 모형을 적용하였으며, 상류단 경계조건을 영천댐으로 설정하고 낙동강에 합류하기까지 약 86km 구간에 대해서 유량과 수질모의를 수행하였다. 모형적용을 위해서는 23개의 reach와 86개 element를 사용하였으며, 주요지류로는 신령천, 청통천, 부기천, 오목천, 남천, 동화천, 신천, 팔거천, 달서천, 이언천를 적용하고, 주요 하 폐수 처리시설을 점오염원으로 입력하였다. 실측자료는 2013년과 2014년의 월자료를 사용하였으며, 유량시나리오는 상류단 영천댐 방류량 조건을 반영하여, 실방류량 조건과 하천유지용수 방류조건, 유지용수 외 추가 25%, 50% 방류조건, 목표수질을 달성하는 방류조건으로 총 5가지의 시나리오를 수행하였다. 상류단 유량이 증가하면 금호강 전반적으로 수질이 개선되나 수질 악화시에는 과도한 방류량을 요구하게 되어, 수질 악화시를 위한 구조적 비구조적 대책도 필요한 상황으로 분석된다.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.497-497
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• 2016

페루의 Rimac강은 수도인 Rima시를 관통하는 강으로 각종 용수공급 등의 기능을 담당하는 중요한 강이지만 광산, 공장 및 도시 등 점?비점오염원으로 인해 오염이 심각해지고 있는 실정이다. 본 연구에서는 Rimac강의 하천복원을 위하여 3단계 수질개선 목표를 설정하고 각 단계별 BOD, TP 및 중금속(Al, As, Cd, Fe) 예측을 수행함으로써 목표달성 가능 평가를 수행하였다. Rimac강 지류인 Rio Santa Eulalia 하천 유입후부터 하구까지 총 57 km를 대상으로 4개의 대구간(Reach), 57개의 소구간(Element)으로 구분하여 QUAL2E 모델을 구축하였다. 2013년을 대상으로 저유량시기(건기)인 12월과 고유량시기(우기)인 1월을 대상으로 BOD, TP, Al, As, Cd, Fe의 모델 재현성을 검토한 결과, Rimac강 하류의 Huaycoloro강 유입이후 BOD, TP가 증가하는 현상을 적절히 재현하는 것으로 나타났다. 중금속은 Romac강 상류와 하류 Huaycoloro강 유입 수질 농도차이가 크지 않아 거리별로 일정한 농도를 나타내는 것으로 모의되었으나 실측정값은 하구로 갈수록 낮아지는 경향이 다소 나타났지만 대체적으로 실측값의 경향을 따르는 것으로 모의되었다. 수질개선 시나리오는 1단계(2016-2018년), 2단계(2019-2021년) 및 최종 3단계(2022-2024년)로 구분하여 저유량시기와 고유량시기의 수질개선 대책에 따른 수질변화를 예측하여 Rimac강 하류의 대표 지점인 La Atargea 취수장 지점에서 목표수질 달성여부를 평가하였다. 저유량시기의 경우, BOD는 1단계 이후 5.9 mg/L에서 목표수질 5.0 mg/L 이하로 농도가 감소되었으며 최종 3단계에 2.2 mg/L로 63.3% 개선하는 것으로 예측되었다. TP는 1단계 25.8% 개선, 3단계는 51.6% 개선되어 목표수질인 0.15 mg/L를 만족하는 것으로 예측되었다. 중금속의 경우 Cd는 당초 수질목표를 만족시키는 상황이었으며 그 외 항목은 Al>As>Fe 순으로 개선효과가 나타났고, 3단계 이후 모두 목표수질을 달성할 것으로 예측되었다. 고유량시기 수질예측 결과, 1단계 BOD, TP는 약 49, 19% 저감효과가 나타났으며 3단계 이후 57, 25%까지 개선되는 것으로 예측되어 목표수질을 만족시키는 것으로 분석되었다. 중금속은 Al이 가장 큰 개선 효과가 나타났으며 3단계에서 77.5%의 개선 효과가 분석되었다. 페루 리막강 유역 수질개선 대책 수립에 따른 수질개선효과 분석 결과, 3단계까지 모든 수질항목의 목표수질 달성이 가능한 것으로 분석되었으나 TP, Al 및 As의 경우에 2단계까지 목표수질 달성이 어려워 더욱 체계적인 관리가 필요할 것으로 판단되었다.

• Journal of Wetlands Research
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• v.25 no.2
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• pp.99-110
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• 2023

Non-point source (NP) pollutants in an agricultural landuse are discharged from a large area compared to those in other land uses, and thus effective source control measures are needed. To develop appropriate control measures, it is necessary to quantify discharge load of each source and evaluate the degree of water quality improvement by implementing different options of the control measures. This study used Hydrological Simulation Program-FORTRAN (HSPF) to quantify pollutant discharge loads from different sources and effects of different control measures on water quality improvements, thereby supporting decision making in developing appropirate pollutant control strategies. The study area is the Gyeseong river watershed in Changnyeong county, Gyeongsangnam-do, with agricultural areas occupying the largest proportion (26.13%) of the total area except for the forest area. The main pollutant sources include chemical and liquid fertilizers for agricultural activities, and manure produced from small scale livestock facilities and applied to agriculture lands or stacked near the facilities. Source loads of chemical fertilizers, liquid fertilizers and livestock manure of small scale livestock facilities, and point sources such as municipal wastewater treatment plants (WWTPs), community WWTPs, private sewage treament plants were considered in the HSPF model setup. Especially, NITR and PHOS modules were used to simulate detailed fate and transport processes including vegitation uptake, nutrient deposition, adsorption/desorption, and loss by deep percolation. The HSPF model was calibrated and validated based on the observed data from 2015 to 2020 at the outlet of the watershed. The calibrated model showed reasonably good performance in simulating the flow and water quality. Five Pollutants control scenarios were established from three sectors: agriculture pollution management (drainge outlet control, and replacement of controlled release fertilizers), livestock pollution management (liquid fertilizer reduction, and 'manure management of small scale livestock facilities) and private STP management. Each pollutant control measure was further divided into short-term, mid-term, and long-term scenarios based on the potential achievement period. The simulation results showed that the most effective control measure is the replacement of controlled release fertilizers followed by the drainge outlet control and the manure management of small scale livestock facilities. Furthermore, the simulation showed that application of all the control measures in the entire watershed can decrease the annual TN and TP loads at the outlet by 40.6% and 41.1%, respectively, and the annual average concentrations of TN and TP at the outlet by 35.1% and 29.2%, respectively. This study supports decision makers in priotizing different pollutant control measures based on their predicted performance on the water quality improvements in an agriculturally dominated watershed.

• Korean Journal of Ichthyology
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• v.32 no.1
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• pp.1-7
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• 2020

Investigations of distribution status and extinction threat evaluation of the Korean endemic species, Iksookimia yongdokensis were undertaken from 2017 to 2018. Among the 22 streams and 97 sampling sites investigated during the study period, samples of I. yongdokensis were collected from 9 streams at 37 sites (from Daejongcheon Stream of Gyeongju-si to Songcheon Stream of Yeongdeok-gun). The appearance of I. yongdokensis was relatively common in streams such as Hyeongsangang River (15 stations), Yeongdeok Oshipcheon Stream (4 stations), Gokgangcheon Stream (4 stations), Chuksancheon Stream (3 stations) and Daejongcheon Stream (3 stations). The main habitat of I. yongdokensis was in pools on flat-land in streams of clean water with slow velocity, and with pebble, gravel and sand bottoms. Previous records of the appearance of I. yongdokensis, indicate they were first seen at seven stations including Jangsacheon Stream, but they were not present in Songcheon Stream. Compared to our results there is evidence as noted for a 38.9% reduction in occupancy within 3 generations (10.5 years), and a decline inhabitat quality. Therefore, I. yongdokensis is now considered vulnerable (VU A2ace) based on the IUCN Red List categories and criteria. The main reasons for the decline were assumed to be dry weathering in the river, the introduction and diffusion of exotic fish species Micropterus salmoides, and river refurbishment project.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.12
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• pp.861-867
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• 2011

In order to understand the extent of contamination of the sediments on the Mankyoung and Dongjin Rivers flowing into the Saemangeum Reservoir, the concentrations of ignition loss (IL), COD, total nitrogen (T-N), total phosphorus (T-P), and heavy metals (As, Cd, Cr, Pb, Zn) were measured. The average concentrations of IL, COD, and T-P were 2.40 (${\pm}2.18$)%, 2.97 (${\pm}3.06$) mg/g sediment, 0.370 (${\pm}0.351$) mg/g sediment, respectively, showing the extent of contamination is not serious. However, the concentrations of these parameters in the samples taken in year 2009 were higher than those in year 2008, indicating the contamination of sediments goes on gradually. The concentrations of T-N were in the range of 0.59~13.11 mg/g sediment with variation of locations and seasons. It was determined that the T-N contamination is serious when the concentrations were compared with the dredging guidelines of sediments in the Korean freshwaters, indicating the countermeasures are required to maintain the water quality of the Saemangeum Reservoir. The concentrations of heavy metals except chromium did not exceed the worrisome level of soil contamination stipulated by the Soil Environment Conservation Act of Korea. The high concentration of chromium to be concerned in some samples from the upstream of Mankyoung River requires source analysis and countermeasure to control the contamination.