• Title, Summary, Keyword: Nakdong River

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Patterns and Trends of Water Level and Water Quality at the Namgang Junction in the Nakdong River Based on Hourly Measurement Time Series Data (낙동강 남강 합류부 수위와 수질 패턴 및 추세)

  • Yang, Deuk Seok;Im, Teo Hyo;Lee, In Jung;Jung, Kang Young;Kim, Gyeong Hoon;Kwon, Heon Gak;Yoo, Je-Chul;Ahn, Jung Min
    • Journal of Environmental Science International
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    • v.27 no.2
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    • pp.63-74
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    • 2018
  • As part of the Four Major Rivers Restoration Project, multifunctional weirs have been constructed in the rivers and operated for river-level management. As the weirs play a role in draining water from tributaries, the aim of this study was to determine the influence of the weirs on the water level of the Nam River, which is one of the Nakdong River's tributaries. Self-organizing maps (SOMs) and a locally weighted scatterplot smoothing (LOWESS) technique were applied to analyze the patterns and trends of water level and quality of the Nakdong River, considering the operation of the Changnyeong-Haman weir, which is located where the Nam River flows into the Nakdong River. The software program HEC-RAS was used to find the boundary points where the water is well drained. Per the study results at the monitoring points ranging between the junction of the two rivers and 17.5 km upstream toward the Nam River, the multifunctional weir influenced the water level at the Geoyrong and Daesan observation stations on the Nam River and the water quality based on automatic monitoring at the Chilseo station on the Nakdong River was affected strongly by the Nakdong River and partly by the Nam River.

Statistical Analysis of the Spatio-temporal Water Quality Characteristics of the Nakdong River (낙동강수계 수질의 시·공간적 특성에 대한 통계학적 분석)

  • Seo, Mijin;Cho, Changdae;Im, Taehyo;Kim, Sanghun;Yoon, Hyunjeong;Kim, Yongseok;Kim, Gyeonghoon
    • Journal of Environmental Science International
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    • v.28 no.3
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    • pp.303-320
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    • 2019
  • Water quality is characterized by various complex factors. Therefore, a systematic understanding of water quality trends is required to carry out a proper evaluation. In this study, we analyzed the spatio-temporal water quality characteristics of the Nakdong River using five-year data from 2012 to 2016. Data was collected on the pH, DO, BOD, COD, SS, TN, TP, TOC, WT, EC, $NH_3-N$, $NO_3-N$, $PO_4-P$, Chl-a, rainfall, and total and fecal coliforms. A total of 38 water quality measurement stations, from Andong1 to Gupo, were considered. Statistical analyses including trend, cluster, and factor analyses were conducted to identify the dominant water quality components affecting the Nakdong River. The Nakdong River was spatially classified into three groups for up-stream (Andong1 to Sangju1), mid/up-stream (Donam to Dalseong), and mid/down-stream (Hwawonnaru to Gupo) data collection, and temporally into two groups for summer/fall (7~10), and the rest of the season (11~6) data. The water quality of the entire Nakdong River showed trends similar to the mid/down-stream section, which indicates the importance of water quality management in this section. Suspended solids, phosphorus, and coliform groups were established as important factors to be considered in the summer/fall season across the river, especially in the mid/down-stream section. Nitrogen and organic matter were identified as important factors to be considered in the rest of the season, especially in the mid/up-stream section. This study could help determine the water quality components that should be intensively monitored in the Nakdong River.

Occurrence and Succession Pattern of Cyanobacteria in the Upper Region of the Nakdong River : Factors Influencing Aphanizomenon Bloom (낙동강 상류 수역에서 남조류 발생과 천이패턴 - Aphanizomenon 속을 중심으로 -)

  • Ryu, Hui-Seong;Park, Hae-Kyung;Lee, Hae-Jin;Shin, Ra-Young;Cheon, Se-Uk
    • Journal of Korean Society on Water Environment
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    • v.32 no.1
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    • pp.52-59
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    • 2016
  • This study investigated the occurrences and succession patterns of harmful cyanobacteria, as well as environmental factors, during a 3-year period (September 2012 to August 2015) in the upper region of the Nakdong River around Sangju weir. A total of 27 cyanobacterial taxa were observed in this study, and classified into 26 species and 1 variety belonging to 11 genera, 5 families, and 3 orders. Cell density ranged from 24 to 42,001 cells/ml, with a geometric mean of 33 cells/ml, during the survey period. The dominant orders differed depending on the survey year; order Oscillatoriales in 2013, Chroococcales in 2014 and Nostocales in 2015. An Aphanizomenon bloom occurred in June 2015 at which time the highest cell density of 36,873 cells/ml was detected in the upper region of the Nakdong River, where as the Aphanizomenon spp. cell density (190-1,704 cells/ml) had been low prior to that time. An Aphanizomenon bloom also occurred at around the same time downstream in the Young River, a major inflow branch of the Nakdong River. The Aphanizomenon cell density along the Nakdong River increased markedly after joining of the YoungRiver, indicating that the Aphanizomenon bloom in the YoungRiver caused a bloom in the Nakdong River. Meteorological and environmental parameters, such as very low precipitation, higher water temperature, pH, and TP concentration, and lower TN/TP ratio, in May and June of 2015 than in 2013 and 2014 exerted marked effects on the Aphanizomenon bloom in June 2015 in the Young River.

Phosphorus and nitrogen loading from the main tributaries into the Nakdong River (낙동강 주요 지천의 인 및 질소부하량에 관한 연구)

  • 허우명;김범철
    • Journal of Environmental Science International
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    • v.4 no.3
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    • pp.187-196
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    • 1995
  • Phosphorus and nitrogen loadings from the main tributaries into the Nakdong River were estimated by measuring phosphorus and nitrogen concentration in the main tributaries, Nakdong River(Kangjung), Kumho River, Heichun, Hwang River, Nam River, Milyang River, and Yangsanchun from May 1994 to October. Total Phosphorus concenuation of Kumho River was vary high, average 1.0 mgP/1. The other rivers were the range 0.05 ~0.15 mgP/1. Total nitrogen concentration of Kumho River was vary high, average 6.27 mgN/1. The other rivers were the range 1.5~3.0 mgN/l. The phosphorus loading from Kumho River, Nakdong River(Kangjung), Nam River, Milyang River, Hwang River, Yangsanchun, and Heichun were calculated to be 1, 108, 603, 198, 57, 34, 23, and 21 tP/yr, respectively. Therefore, the loading from Kumho River accounted for 45 "yo of total loading, 2, 042 tP/yr, The nitrogen loading from Nakdong River (Kangjung), Kumho River, Nam River, Milyang River, Hwang River, Heichun, and Yangsanchun were calculated to be 12, 636, 7, 411, 2, 611, 1, 523, 779, 608, and 391 tN/yr, respectively. Therefore, the loading from Nakdong River(Kangiung) and Kumho River accounted for 50 % and 30% of total loading, 25, 959 tN/yr, respectively.vely.

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Evaluation of Diatom Growth Potential in Midstream and DownstreamNakdong River (낙동강 중. 하류에서의 규조류 성장잠재력 평가)

  • Kwon, Young-Ho;Seo, Jung-Kwan;Park, Sang-Won;Yang, Sang-Yong
    • ALGAE
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    • v.21 no.2
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    • pp.229-234
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    • 2006
  • For the test organism of algal growth potential (AGP), the diatom in the genus Stephanodiscus which cause blooms in the Nakdong River was used instead of generally used strains of Selenastrum, Microcystis, or Anabaena. AGP results indicated that all the samples in the Nakdong River except for that from the Nakdan Bridge site were eutrophic state. Furthermore, the sample from Kumho River site was hypertrophic state. In the main stream Nakdong River, the value of AGP was lowest at the upstream Nakdan Bridge site and was highest at Koryoung Bridge site which is just downstream of Kumho River confluent point indicating the seriousness of pollution contributed by the Kumho River to the Nakdong River. Changes in the concentration of nutrients before and after the AGP tests and inter-relationship among the nutrients indicated that the growth of the Stephanodiscus in the AGP tests were mostly affected by the nitrate, silicate and phosphate. The limiting nutrient was identified by the nutrient addition experiments and the results showed that phosphate was the limiting nutrient for the growth of Stephanodiscus in the tested samples.

A Study on Efficiency of Water Supply through Conjunctive Operation of Reservoirs and Multi-function Weirs in the Nakdong River (낙동강수계 댐과 다기능보의 연계운영을 통한 용수공급효율화에 관한 연구)

  • Ahn, Jung Min;Im, Toe Hyo;Lee, In Jung;Lee, Kyung-Lak;Jung, Kang Young;Lee, Jae Woon;Cheon, Se Uk;Park, In Hyeok
    • Journal of Korean Society on Water Environment
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    • v.30 no.2
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    • pp.138-147
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    • 2014
  • In order to determine the best operating rules for the Nakdong River, three cases were applied to analyze the simulated results of water supply capacity by HEC-ResSim model. This study discussed to present the best operating rules for conjunctive operating of existing the dams and new constructed the weirs through system network. The system network was constructed considering the water supply, the river environment and the operating facility. The water supply capacities are separately evaluated for each case applying the best rules. It is case1 that the dams are operated individually, case2 that the dams are operated in conjunction with the others dams, and case3 that dams and weirs are operated in conjunction with the others dams-weirs. Comparing the cases, case 3 has shown the best water supply capacity of the Nakdong River.

Flow Duration Curve Analysis for Nakdong River Basin using TMDL Flow Data (오염총량관리 유량측정자료를 이용한 낙동강 유역 유황분석)

  • Kim, Jae Chul;Kim, Sangdan
    • Journal of Korean Society on Water Environment
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    • v.23 no.3
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    • pp.332-338
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    • 2007
  • In this study the flow duration curves for Nakdong river basin are analyzed. The TANK model is used as a hydrologic simulation model whose parameters are estimated from 8-day intervals flow data measured by NIER Nakdong River Water Environment Laboratory. As a comparison result between generated natural and present river flow, the present river flow is higher than the natural river flow in the up- and mid-stream of Nakdong river, while the present river flow is lower than the natural river flow in the down stream of Nakdong river.

Relations of Nutrient Concentrations on the Seasonality of Algal Community in the Nakdong River, Korea (낙동강 조류군집의 계절적 변화와 영양염 농도와의 관계)

  • Yu, Jae Jeong;Lee, Keung Lak;Lee, Hye Jin;Hwang, Jeong Wha;Lyu, Heuy Seong;Shin, La Young;Park, A Reum;Chen, Se Uk
    • Journal of Korean Society on Water Environment
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    • v.31 no.2
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    • pp.110-119
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    • 2015
  • The construction of the eight large weirs in the Nakdong River, the second largest river in Korea, caused big changes in the physical environment of the water system. Algal communities and their correlations with environmental factors, mainly nutrients were studied at five weir areas in the Nakdong River from 2010 to 2013. Water quality, hydrodynamics and algal composition were investigated. Results showed that flow velocities were reduced compared with that before weir construction near the areas where are located in the mid and upstreams of the Nakdong River. A seasonal algal community succession was observed and it was mainly correlated with temperature and phosphorus. Diatoms were dominated from winter to spring months and massive diatomic blooms of Stephanodiscus sp. occurred early in March during survey period. Cyanobacterial blooms of Microcystis sp. occurred from July to September 2013 and was preceded by the lower total phosphorus concentration of $0.05mg\;L^{-1}$. The correlations between total phosphorus concentrations and algal abundances were not significant during the survey periods. However, significant correlation with cyanobacteria was found in the period of weir construction after only at the GG survey site and blooms periods of 7 times in the survey sites, and its correlation coefficients were 0.53 (p<0.001) and 0.42 (p<0.01) respectively. When algal bloom was observed, partially low nutrient concentration was observed in the Nakdong River. In conclusion, partially low nutrient concentration which may result from algal bloom was observed, and we presume it caused the reduction of algal abundunces.

The Effect of for Major River Project and Kumho River on Nakdong River's Water Quality - Focused on Kangjung-Koryung Weir (4대강 사업과 금호강의 수질이 낙동강 본류에 미치는 영향에 대한 연구 - 강정고령보 공사현장을 중심으로)

  • Hwang, Sam-Jin;Bae, Hun-Kyun;Kim, Hak-Yoon
    • Journal of Environmental Science International
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    • v.22 no.6
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    • pp.695-703
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    • 2013
  • In this study, the effects of four major river project and Kumho River, second biggest branch of Nakdong River, were investigated to provide basic data for proper management of Nakdong River's water quality. Daily sampling processes at three different points, Munsanri (the upper side of Kangjung-Koryung weir), Kangchang (the outlet of the Kumho River) and Samunjin (the lower side of Kangjung-Koryung weir and junction of Kumho River and Nakdong River), were conducted from May 1st 2011 to Sep. 4th 2011. Water samples were analyzed for nine factors, DO, BOD, COD, T-N, T-P, pH, turbidity, SS, and coliform. As demonstrated by the results, concentrations of BOD, T-N, T-P and coliform at Nakdong River were affected by water quality of Kumho River while SS and turbidity were affected by constructions for Kangjung-Koryung weir. Further studies, for example, affects of wastewater treatment facilities, should be followed.