• 환경생물
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• 제36권3호
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• pp.424-437
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• 2018

The incidence of freshwater algal bloom has been increasing globally in recent years and poses a major threat to environmental health. Cyanobacteria are the major component of the bloom forming community that must be monitored frequently. Their morphological identities, however, have remained elusive, due to their small size in cells and morphological resemblances among species. We have analyzed molecular diversity and seasonal changes of cyanobacteria in Paldang Reservoir, Korea, using morphological and 16S rRNA pyrosequencing methods. Samples were collected at monthly intervals from the reservoir March-December 2012. In total, 40 phylotypes of cyanobacteria were identified after comparing 49,131 pyrosequence reads. Cyanobacterial genera such as Anabaena, Aphanizomenon, Microcystis and Synechocystis were predominantly present in samples. However, the majority of cyanobacterial sequences (65.9%) identified in this study were of uncultured origins, not detected morphologically. Relative abundance of cyanobacterial sequences was observed as high in August, with no occurrence in March and December. These results suggested that pyrosequencing approach may reveal cyanobacterial diversity undetected morphologically, and may be used as reference for studying and monitoring cyanobacterial communities in aquatic environments.

• 한국물환경학회지
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• 제35권6호
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• pp.557-566
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• 2019

Paldang is a river reservoir in the Midwest of Korea, which is a drinking water source for the metropolitan area. Since the Paldang Reservoir is shallow, and has a short hydraulic residence time, its water quality is directly impacted by two incoming rivers, the north Han River (NHR) and the south Han River (SHR). The NHR has different seasonal patterns of water temperature from the SHR because the NHR is greatly impacted by the discharge water from upstream dams. The electrical conductivity (EC) and other material concentrations of the SHR are usually higher than those of the NHR because its basin is limestone-based. The difference in water temperature in the two rivers causes density flow, and the distribution of the EC within the reservoir can be an indicator for monitoring density flow. From the vertical gradient of the EC at the dam site, from spring to fall, it was confirmed that the SHR flowed into the upper layer, and the NHR flowed into the lower layer, and vice versa at other times. The relative difference (RD) of the EC between the upper layer and the lower layer at the dam site was used as an indicator for density flow. The RD of the EC showed a very significant correlation with the RD of total organic carbon (r = 0.70, p < 0.001) and the RD of total nitrogen (r = 0.58, p < 0.01). This relationship is based on the assumption that the difference in electrical conductivity and water quality between the SHR and the NHR is constant. However, in many cases this assumption is inconsistent. Thus, further study is needed on more suitable indicators to evaluate the impact of density flow on water quality.

• 유기물자원화
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• 제21권3호
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• pp.93-98
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• 2013

본 연구에서는 최근 자주 거론되는 녹조발생의 주요 원인을 찾아보고자 하였다. 지난 십년이상의 기상자료 및 수질에 대한 실측자료를 이용하여 녹조원인에 대한 통계적 접근을 시도하였다. 팔당호를 대상으로 한 연구에서 조류예보일수에 일정한 추세를 발견할 수는 없지만 발생년도에는 10일 이상씩 나타나는 특징을 보여 주고 있으며 최근 5년간은 발령일수가 증가하고 있어 주의해야 할 것으로 판단되었다. 유속의 자료 대신 사용된 방류량을 보면 조사기간 중 세 배 정도의 차이가 나는 해도 관찰되었다. 클로로필a에 대한 다른 지표들의 상관계수를 보면 뚜렷한 한 가지 지표로 나타나지 않아서 상관계수 0.4를 넘는 요인은 없었다. 그 중 중요한 요인으로 나타나는 것은 일조시간, BOD, 그리고 방류량이며 일조시간과 BOD는 양의 상관 그리고 강수량과 방류량은 음의 상관을 나타내고 있어서 광합성미생물에 의한 현상으로서 타당한 결과로 보였다. 수온과 총인농도는 중요한 요인이 될 것으로 예상되었으나 결과는 낮은 상관성을 보였다. 이상의 결과로 판단할 때 조류발생에는 여러 가지 요인이 복합적으로 작용하며 그중 일조시간, BOD, 그리고 유속 또는 방류량은 중요한 요인으로 판단된다. 방류량과 다른 요소와의 상관관계도 조사하였다. 강수량과 수온이 양의 상관을 보이는 것은 계절적인 효과로 타당해 보였다.

• 생태와환경
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• 제37권3호통권108호
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• pp.272-281
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• 2004

팔당호의 유기물 수지 산정을 위해 팔당호내 일차생산력을 측정하고 유입하천의 유입유기물량 및 방류유기물량을 측정하여 유기물부하에서 내부생성유기물의 기여도를 평가하였다. 식물플랑크톤에 의한 일차생산력은 지점과 시기에 따라 큰 차이를 보여 3회 조사결과 $101{\sim}2701\;mgC\;m^{-2}day{-1}$의 범위로 나타났으며, 체류시간이 길고, 수체내 클로로필 a농도가 높았던 6월에 모든 지점에서 높은 생산력을 보였다. 빈번한 강우로 체류시간이 짧고 조류현존량이 적었던 4월과 8월의 조사에서는 총 유기물유입량에서 내부생성유기물량은 약 7%를 차지하였고 이중 식물플랑크톤에 의한 내부생산기여도는 약 5%로 매우 낮았다. 그러나 조사일 전후로 강우가 없어 수체가 안정되었고 외부유입유기물량이 적었던 6월 조사에서는 식물플랑크톤에 의한 내부생산 기여도가 29.0%를 보였다.

• Ecology and Resilient Infrastructure
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• 제6권1호
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• pp.12-22
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• 2019

본 연구에서는 팔당호 내 주요지점에서 수심별 연속 수리 및 수온 조사를 수행하여 팔당호의 시공간적 물순환 특성을 파악하고자 하였다. 이포보와 청평댐에서의 수온 및 방류 패턴의 차이로 인하여 팔당호 내 북한강 및 남한강 구간에서의 흐름 및 수온 변동특성이 상이하게 나타났다. 수직혼합기에는 북한강과 남한강 구간의 전 층에서 하류방향 흐름이 우세하게 나타났다. 성층형성기에 이포보 방류수의 수온이 청평댐 방류수의 수온보다 높았으며, 이로 인해 북한강 하류 구간에서 표층은 상대적으로 고온수가 위치하여 상류방향 흐름으로 배수 현상이 나타나고 수렴대가 형성되었다. 남한강 하류 구간은 중층과 저층에서 저온수가 분포하여 상류방향 흐름이 나타나고 표층과 혼합되기 어려운 이층류 구조를 나타내었다.

• 한국물환경학회지
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• 제33권3호
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• pp.282-290
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• 2017

A long-term resuspension of small particles, called persistent turbidity, is one of the most important water quality concerns in the dam reservoirs system located in North Han River. Persistent turbidity may incur aesthetic nuisance and harmful effect on the ecosystem health, in addition to elevated water treatment costs for the drinking water supply to the Seoul metropolitan area. These sufferings have been more intensified as the strength and frequency of rainfall events increase by climate change in the basin. This study was to analyze the effect of an extreme turbidity flow event that occurred in 2006 on the serial reservoirs system (Soyang-Uiam-Cheongpyung-Paldang) in North Han River. The CE-QUAL-W2 model was set up and calibrated for the river and reservoirs system using the field data obtained in 2006 and 2007. The results showed that Soyang Reservoir released turbid water, which was classified as the TSS concentration is greater than 25 mg/L, for 334 days with peak TSS of 264.1 mg/L after the extreme flood event (592.7 mm) occurred between July 10 and 18 of 2006. The turbid water departed from Soyang Reservoir reached at the most downstream Paldang Reservoir after about 20 days and sustained for 41 days, which was validated with water treatment plant data. Since the released water from Soyang Reservoir had low water temperature and high TSS, an underflow formed in the downstream reservoirs and vertically mixed at Paldang Reservoir due to dilution by the sufficient inflow from South Han River.

• 한국해양바이오학회지
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• 제16권1호
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• pp.63-86
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• 2024

This study analyzed the distribution, diversity, and density variation of algal clusters in a freshwater reservoir from an oceanic island and a traditional inland water system to gain insights on future marine freshwater resource management. In the Paldang water system (Han River), despite the upstream Paldang Dam and the downstream Jamsil underwater reservoir being in the same meteorological zone, their algae density patterns varied inversely. The distinct algal cluster structure (diversity/dominance) of Paldang was altered in the downstream reservoir, suggesting that physical devices aid algae management in traditional water systems. In contrast, 24 out of 35 genera (63.2%) identified in the Jeolgol Reservoir (Baeknyeong Island) were unique, lacking regulatory mechanisms, and existing in a complex ecotone. The desmid Chlorophyceae Cosmarium, adapted to higher photosynthetic stress and low temperatures, dominated in January (38.04%) and August (86.45%) during the periods of extreme photosynthetic stress. Jeolgol's annual algal cluster structure (H' 2.097; D 0.259; S' 35) demonstrated higher stability than Paldang (H' 1.125; D 0.448; S' 13) and the Jamsil underwater reservoir (H' 1.078; D 0.469; S' 12), maintaining an H' above 1.5 even during midwinters. No evidence of TN/TP inflow from surrounding soils was observed, even during torrential rainfalls, with phosphorus being the limiting factor for algal growth. TOC, BOD, chlorophyll-a, and turbidity peaked during Cosmarium bloom. Future climate change is expected to cause fluctuations in algal clusters and related water quality factors. The complex transitional nature of the Jeolgol Reservoir, its algal diversity, and the interspecies interactions contribute to the high stability of its algal community.

• 한국동물학회:학술대회논문집
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• 한국동물학회 1998년도 한국생물과학협회 학술발표대회
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• pp.193.2-193
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• 1998

• 한국물환경학회지
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• 제33권6호
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• pp.696-714
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• 2017

Simple material budget models were developed to predict the spring season (March ~ May) water quality for a river-type reservoir Paldang, in the Republic of Korea. These models are available at mixed water bodies whose light intensity is negligible at the bottom. The calculated data from the models fit quite well with field data collected for 30 years, from 1988 to 2017. The apparent settling velocity of total phosphorus was estimated to be $110m\;d^{-1}$. The critical hydraulic load that determines the usability of phosphorus for algal production appeared to be about $2.0m\;d^{-1}$. When a hydraulic load was larger than the critical value, the concentrations of chlorophyll ${\alpha}$ ($Chl.{\alpha}$), chemical oxygen demand (COD), and 5-day biochemical oxygen demand BOD in the reservoir water became insensitive to internal algal reactions. The model analysis showed that the allochthonous COD continued to increase while the allochthonous BOD slightly decreased after 1999. The decrease of allochthonous BOD is due to the expansion of sewage and wastewater treatment plants in the watershed. The increase of allochthonous COD seems to result from the increase in anthropogenic non-point sources as well as the increase in the discharge of natural organic matters due to climate change. Organic matter of algal origin continued to increase until the mid-2000s, but recently it has decreased as the phosphorus concentration has decreased. The COD and BOD of algal origin increased from 35 % and 27 % during 1988 ~ 1994 to 43 % and 40 % during 2000 ~ 2010, respectively, and then decreased to 25 % and 28 % during 2011 ~ 2017.

• 한국물환경학회지
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• 제30권4호
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• pp.429-440
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• 2014

This study was conducted to investigate the main cause of water quality deterioration during the spring season in the transition zone between the South Han River and the river-reservoir Paldang. A water quality model modified from QUAL2E (U.S.EPA) was used, and the model showed that eutrophication and algal production in the low flow season affected about 60% of the organic pollution at the downstream of the South Han River. This result means that phosphorus control is prior to external organic material management to ameliorate the deterioration of water quality in the water body.