• 한국환경농학회지
• /
• 제18권1호
• /
• pp.6-7
• /
• 1999

The water quality at Mankyeong River was surveyed 13 sites of main stream for 6 months from April to September in 1995 and 1997. The monthly average value of $NH_4-N$, $SO_4^{2-}$ and $Cl^-$ showed the highest peak in April while that of $NO_3-N$ showed the highest peak in August. The monthly average value of COD showed the highest peak in September at high temperature season. Concentrations of $NH_4-N$ and $SO_4^{2-}$ in Mankyeong River stream exceeded the standard water quality criteria in many sites. The water quality of Mankyeong River stream was not suitable for the irrigation source excepted the sites such as Hari, Gosan stream and Soyang stream. The floodgate of Mokcheon, Yocheon, Jeonju and Samcheon stream were rapidly polluted by the sewage of city, otherwise the Iksan stream was rapidly polluted by the sewage of swine. The sum of ionic concentrations in Mankyeong River stream was the highest at floodgate of Yocheon by influence of the sewage from city and industry. The order of the major anions and cations concentration in Mankyeong River stream were $SO_4^{2-}$ > $Cl^-$ > $NO_3-N$ > $SO_4^{3-}$ and $Na^+$ > $Ca^{2+}$ > $NH_4^+$ > $Mg^{2+}$ > $K^+$, respectively.

• 한국환경보건학회지
• /
• 제27권3호
• /
• pp.49-56
• /
• 2001

The water quality simulation was carried out to predict water quality in Tan stream of the Han river using water quality model, QUAL2E. In the end, the future variations in water quality of Tan stream were simulated and the prediction of the impacts of Tan stream on water quality in the Han river was carried out by applying the Tan stream simulation results into the model. The results are as follows. The predicted results of future water quality of Tan stream suggested that the concentrations of BOD, T-N and T-P at Chungdam bridge would increase to 0.68~0.77 mg/$\ell$, 1.33~1.62 mg/$\ell$ and 0.05~0.06 mg/$\ell$, respectively in 2006 and 2011 and that with the implementation of advanced treatment in Sungnam and Tanchun sewage treatment plants, the concentration of T-N would be reduced more as the amount of treated sewage increase, while the concentration of T-P would stay 0.49 mg/$\ell$. The results obtained from simulation of the impacts of future Tan stream water quality improvement on the main stream of the Han river showed that with implementation of advanced treatment in both Sungnam and Tanchun sewage treatment plants, the concentration of T-N, T-P and chlorophyll-a at Hangang bridge and Heangju bridge would be reduced by 11.6%, 7.7% and 20.9%, respectively in 2..6 and by 13.6%, 9.4% and 22.2%, respectively in 2011, which indicates that the effect on the reduction of T-N and T-P would be relatively significant while the effect on the decrease of algae would be slight.

• 한국어류학회지
• /
• 제32권1호
• /
• pp.1-7
• /
• 2020

우리나라 고유종 동방종개 Iksookimia yongdokensis의 분포현황 및 멸종위협을 평가하기 위하여 처음으로 정밀분포조사를 2017년부터 2018년까지 2회 실시하였다. 동방종개는 조사기간 중 22개 하천, 97개 지점을 조사하여 9개 하천, 37개 지점 (경주시 대종천~영덕군 축산천)에서 서식을 확인하였다. 서식 지점 수는 형산강(15개 지점), 영덕오십천(4개), 곡강천(4개), 축산천 (3개), 대종천 (3개) 등의 순으로 많았으며, 주로 평지형 하천의 물이 맑고 유속이 느리며 자갈과 잔자갈, 돌, 모래가 쌓여 있는 소(pool)에 서식하고 있었다. 본 결과를 과거 출현기록과 비교하면, 처음으로 장사천에서 서식을 확인하였고 7개의 신규 서식지를 발굴하였으나, 과거 서식지인 송천에서는 서식을 확인하지 못하였다. 동방종개의 멸종위협 등급을 IUCN 평가기준에 따라 평가했을 때 서식지 (점유면적)가 3세대(10.5년) 동안 38.9%가 감소하고, 서식지의 질이 하락하였기 때문에 취약(VU A2ace)으로 평가되었다. 주된 감소요인은 가뭄으로 인한 하천 건천화, 외래종 배스 Micropterus salmoides의 도입 및 확산, 하천의 개보수 사업 등이었다.

• 생태와환경
• /
• 제34권2호통권94호
• /
• pp.119-125
• /
• 2001

경안천과 팔당호 주요 유입부에서 2000년 9월부터 2001년 2월까지 수중 총세균수의 분포 및 변동을 조사하였다. 경안천 본류에서 총세균수는 하수처리장 배출수가 유입될 때 뚜렷이 증가하였다. 경안천 본류에서 유하거리 (km)당 총세균의 소멸량은 0.13${\times}10^{6}$cells/ml로서 하류로 이송되면서 하상에 침강 소멸되는 양이 상당하였다. 총세균수의 변동은 9${\sim}$10월, 11월 및 12${\sim}$2월에 평균값이 각각 1.74${\sim}$3.10${\times}10^{6}$cells/ml, 1.86${\sim}$7.30${\times}10^{6}$cells/ml 및 4.56${\sim}$8.75${\times}10^{6}$cells/ml 범위로서 세균의 생물량은 고수온기에 적었고 저수온기에 오히려 증가하였다. 총세균수는 수온이 >$10^{\circ}C$인 시기(9${\sim}$10월)보다 <$10^{\circ}C$인 저수온기(12${\sim}$2월)에 2.1${\sim}$3.0배 풍부하였다. 총세균수로 평가하였을 때 수질은 부영양상태였고 하수처리장 배출수는 경안천과 팔당호의 미생물 오염에 대한 가장 큰 source로 평가되었다. 경안천 뿐만 아니라 팔당호의 상수원 수질을 보호하기 위해서는 하수처리장 배출수 관리에 대한 대책 마련이 매우 시급한 것으로 판단되었다.

• 한국환경생태학회지
• /
• 제20권2호
• /
• pp.259-266
• /
• 2006

2004년 5월 29일부터 2004년 11월 6일까지 4회에 걸쳐 원주천의 섭식기능군을 이용해 군집분석을 하였다. 조사기간동안 출현한 수서곤충은 총 8목 37과 62속 92종이었으며, 원주천의 현존량과 동태는 지점 7, 9를 제외하고 양호하였다. 원주천의 섭식기능군(FFG)을 알아본 결과 본류는지점 1에서 9로 갈수록 써는무리(shredders)와 긁어먹는무리(scrapers)가 점차적으로 점유율이 낮아지고 주워먹는무리(collectors-gathering)와 걸러먹는무리(collectors-flitering)가 현저하게 증가하였다. 지점 2는 다른 지류지점에 비해 긁어먹는무리와 써는무리가 다소 높은 비율을 나타내어 산간계류의 특성을 가지고 있었다. 원주천의 각 지점별 유사도분석(UPGMA)을 한 결과 최상류수역을 보이는 지점 1, 2와 중류역의 특성을 보이는 지점 3, 4, 5, 6, 7, 8 그리고 최하류역으로 보이는 지점 9 등, 3개의 그룹으로 나뉘었다.

• 한국안전학회지
• /
• 제9권1호
• /
• pp.155-160
• /
• 1994

A study of stream pollution caused by construction of the Industrial Complex in Agricultural Area of Chung Chong Nam Do were descrived here. The five main results of this studies are summerized. First, since 1988, among the companies moved in the industrial complex area, the number of electric and electronic companies have increased compared with food companies requiring much BOD. This Is very desirable to reduce the water pollution. Second, the average Biochemical Oxygen Demand(BOD) of Masan stream was the highest and it was decreased in the order of Yudug, Jo and Jungan stream. Third, although the concentration of heavy metals such as Cd and C $r^{6+}$ are not off the limit and the amount of it is small, it is desirable to introduce a chemical process to remove these metals. Fourth, since the wastewater from industrial complex area is the major factor in stream pollution, the laws associated with environmental protection should be enforced even then if the Industrial complex area with food and chemical companies produce wastewater less than 500ton/day. Fifth, it is required to improve a facilities which separete living wastewater from inderstrial wastewater In Kaya-gok and Nojang industrial complex areas.

• 한국농공학회논문집
• /
• 제52권4호
• /
• pp.53-61
• /
• 2010

An impervious cover in the watershed management has been used as effective indicators. It is a very useful barometer to measure the impacts of watershed development on aquatic systems. Hence, it is necessary to survey the impervious cover of a watershed and to develop an impervious cover model (ICM) for supporting best management practices. The main objectives of this study were to investigate the spatial patterns of the impervious cover, to calculate landscape indices using FRAGSTATS, and to develop an ICM in the Gap-stream watershed and its six sub-watersheds. The results showed that the impervious cover of the Gap-stream watershed increased from 4.9 % in 1975 to more than 11.2 % in 2000, the number of impervious cover fragments increased from 662 to 3,578, and the landscape shape index increased from 27.0796 to 91.1982. Fragmentation was severe within the Yudeungcheon downstream and the Gapcheon downstream of six sub-watersheds. This paper presented the results derived landscape indices to define landscape patterns and structure for the Gap-stream watershed. Our results indicate that altered land use might be influenced changes in landscape structure.

• Environmental Engineering Research
• /
• 제21권2호
• /
• pp.211-218
• /
• 2016

Cheonggye-cheon is a partly restored urban stream located in central Seoul. We monitored fecal contamination using three different fecal indicators, total coliforms (TC), fecal coliforms (FC) and E. coli, to assess differences in each indicator on days of varying weather conditions. Presumptive TC, FC and E. coli colonies were identified by their 16S rRNA sequences. The results showed that enumeration of E. coli provided a better reflection of fecal contamination of the stream than TC and FC. The main sources of contamination were the inflow of fecal-polluted groundwater from the vicinity of a subway line and two inflowing streams. The fecal contamination was worsened on days with heavy rain because untreated sewage from a collecting facility flowed into the stream. Moreover, growth potential of fecal indicator (E. coli) in situ induced by algal exudates was measured. Our results suggest that an appropriate standard based on E. coli rather than TC and FC should be established for improving water quality management strategies of Cheonggye-cheon in the future.

• 상하수도학회지
• /
• 제23권6호
• /
• pp.763-768
• /
• 2009

Ozone is a strong oxidant and a powerful disinfectant. In general, it has been used in drinking water treatment during last 100years. Ozone dissolution features are defined by the two categories of ozone contactors, bubble-diffuser and sidestream ozone contactor. Currently, sidestream-injection systems are gaining in popularity but operating cost might be slightly higher. Sidestream ozone system dissolve ozone into a sidestream flow via an injection setup or in the main process flow stream in some sidestream arrangements. The sidestream flow is subsequently mixed with the main process flow stream, which is directed to a reation tank or pipeline for oxidation and disinfection reactions. The purpose of this study is to suggest optimal operating pressure, to figure out the static-mixer effect and to understand the microbubble characteristics of ozone to improve dissolution efficiency.

• 수산해양기술연구
• /
• 제13권1호
• /
• pp.1-5
• /
• 1977

A series of echo-sounding and current measurements as well as the drogue and the drift bottle experiments were carried out in Asan Bay since November 1974. Several sand bars or sand flats covered by silts were developed at ebb tide in the bay. Sand waves and sand ripples were seen on the surface of the sand bars, around which sea channels of 8~ 12 meters in depth are formed. The main stream axis of the flood current which is separated into east and west branch flows southward. A cyclonic and an anticyclonic eddy are developed at the early stage of flood tide. They are transformed into a clockwise eddy before the slack water. The maximum tidal current speed observed was 3.1 ~ 3.2 knots at the entrance of the bay, while it was 1.O ~ 2.8 knots in the bay. The location of the main stream axis of the tidal current coincides well with the sea channel. A salt wedge was observed at the estuary of the Sabgyo-cheon River.