2015년 4월부터 10월까지 남양호 유역의 어류군집 특성을 밝히기 위해 유입하천을 포함한 9개 지점에서 조사 하였다. 남양호 유입하천 (St. 1~St. 6)에서 27종 5,899개체가 출현하였으며 우점종은 참붕어 Pseudorasbora parva (33.5%)로 나타났다. 남양호 (St. 7~St. 9)에서는 20종 5,672개체가 출현하였으며 우점종은 붕어 Carassius auratus (32.2%)로 나타났다. 남양호 유역에서 츨현한 고유종은 각시붕어 Rhodeus uyekii, 가시납지리 Acanthorhodeus gracilis, 몰개 Squalidus japonicus coreanus, 왜매치 Abbottina springeri, 얼룩동사리 Odontobutis interrupta 5종으로 유입하천에서 전체 출현 종의 18.5%, 남양호에서 15% 로 유입하천에서 고유종의 빈도가 높게 나타났다. 외래종은 떡붕어 Carassius cuvieri, 블루길 Lepomis macrochirus, 배스 Micropterus salmoides가 출현하였으며 유입하천에서 전체 출현 종의 7.4% 남양호 15.0%로 호소 내에서의 외래 종의 빈도가 높게 나타났다.

The tributaries of Daechung Lake play an important role in controlling eutrophication in the lake, which is used for agricultural purposes and as potable water. However, water quality properties were not extensively studied in the tributaries of Daechung Lake. The objectives of this study are to investigate spatial and temporal properties of water quality and to characterize streams which could threaten water quality of Daechung Lake. For this study, water samples were weekly or monthly collected from February 2014 to October 2014 in 9 streams. Water quality parameters analyzed in this study include biochemical oxygen demand (BOD), chemical oxygen demand (COD), total organic carbon (TOC), total nitrogen and phosphorus (TN and TP), suspended solids (SS), and chlorophyll a. Based on temporal distribution and principal component analysis, BOD, COD, TOC, SS, and TP were controlled by not only river discharge that increased during summer due to heavy rain fall, but also due to anthropogenic input (e.g., bridge construction and/or agricultural activity). Dilution is also one of the factors explaining TN and conductivity, both of which decreased with increased discharge. Generally, concentrations of contaminants (BOD, COD, TOC, TN and TP) in the tributaries were higher than those of Daechung Lake. However, pollution load indicated that only the main channel of Geum River and Sook Stream may largely influence lake waters, attributed mostly to their large volumes. This implies that the main channel and Sook Stream are the major influences on the water quality of Daechung Lake.

The tributaries of Daechung Lake play an important role in controlling eutrophication in the lake, which is used for agricultural purposes and as potable water. However, water quality properties were not extensively studied in the tributaries of Daechung Lake. The objectives of this study are to investigate spatial and temporal properties of water quality and to characterize streams which could threaten water quality of Daechung Lake. For this study, water samples were weekly or monthly collected from February 2014 to October 2014 in 9 streams. Water quality parameters analyzed in this study include biochemical oxygen demand (BOD), chemical oxygen demand (COD), total organic carbon (TOC), total nitrogen and phosphorus (TN and TP), suspended solids (SS), and chlorophyll a. Based on temporal distribution and principal component analysis, BOD, COD, TOC, SS, and TP were controlled by not only river discharge that increased during summer due to heavy rain fall, but also due to anthropogenic input (e.g., bridge construction and/or agricultural activity). Dilution is also one of the factors explaining TN and conductivity, both of which decreased with increased discharge. Generally, concentrations of contaminants (BOD, COD, TOC, TN and TP) in the tributaries were higher than those of Daechung Lake. However, pollution load indicated that only the main channel of Geum River and Sook Stream may largely influence lake waters, attributed mostly to their large volumes. This implies that the main channel and Sook Stream are the major influences on the water quality of Daechung Lake.

The purpose of this study was to analyze fish fauna and species compositions along with trophic guilds, tolerance indicators, and fish community conditions before weir construction (BWC) and after weir construction (AWC) in the Yeongsan River watershed. Total 45 and 44 fish species were sampled in BWC and AWC, respectively without any distinct differences through weir constructions. Fish fauna analysis revealed that the dominant species was the same, Zacco platypus with 24.3% and 20.8% in BWC and AWC, respectively. However, the subdominant species were Carassius auratus with 8.9% in BWC but Opsarichthys uncirostris amurensis with 20.3%, almost identical that of the dominant species AWC. This phenomenon showed the distinct modification of species composition in the watershed. We sampled the 1st class endangered species, Liobagrus obesus in tributary stream as previously reported. Also Culter brevicauda was sampled in the mainstream of Yeongsan River watershed and this was the first sampled record in this watershed. One of the most important features were an increase of exotic species, such as Micropterus salmoides and Lepomis macrochirus, with 3.2% BWC vs. 10.2% AWC as well as the increase in tolerant species with 49.2% BWC vs. 73.7% AWC, indicating ecological degradation through weir construction. Overall, our results indicated that fish fauna and composition analyses showed distinct ecological degradations related to increases of exotic and tolerant species AWC. Further long-term studies of fish monitoring should be conducted in the future to configure existent status of river conditions and to provide key information in order to conserve the healthy ecosystem.

하천식물의 자연환경조건을 규명하기 위하여 국내 중소규모의 10개 하천(한강수계의 문산천, 곡릉천, 낙동강 수계의 미천, 쌍계천, 남천, 북한강 수계의 가평천, 조종천, 남한강 수계의 청미천, 양화천, 복하천)을 선별한 다음에 각 하천의 전 유로연장에서 가장 자연성이 높은 구간 1km를 중점조사구로 결정하였다. 그리고 그 구간에 대하여 2004~2007년 여름에 식물조사를 belt transect 방법으로 실시하였다. 그 결과 총 296종이 출현하였는데, 그 중에서 출현빈도가 높은 121종과 대상지의 환경인자(저수로 물로 부터의 거리, 하상재료의 크기, 사주의 개수, 대상지의 고도, 하상경사, 저수로의 폭, 하천수질측정값)간의 RDA (Redundancy analysis) 및 피어슨의 상관성 분석을 실시하였다. 그 결과 대입된 식물종들은 대상지의 고도, 하상경사, 사주의 개수의 인자와는 유의성이 없었으나, 하상재료의 크기, 저수로의 폭, 전기전도도와 인산염인(PO4-P)의 농도와는 상관성이 “매우 높은~보통”으로 분석되었다. 그리고 이 식물들은 현재의 그들의 수환경 조건을 그대로 반영하고 있기 때문에 분석방법의 신뢰성에 큰 무리가 없으나, 사례의 다양성 부족으로 다른 사례하천으로의 확대해석은 어려울 것이다. 그러나 본 자료는 앞으로 하천특성에 따른 식물연구나 하천식물 선정을 위한 기초 자료로는 이용할 수 있을 것이다.

Concern about water quality and pollution was heightened as contaminants flowed into the Namhan River downstream of the Chungju Dam. Thus, this study calculated the Real-Time Water Quality Index (RTWQI) using monthly average water quality monitoring data for major tributaries that require water quality control, which were obtained between 2010 and 2019. To review the applicability of the RTWQI for water quality assessment in the major tributaries of the Namhan River, it was compared with the living environment standard river. The calculated RTWQI result indicated that Bokhacheon, with 59 points, was in the “fair” grade, and this stream was identified as a tributary that preferentially requires water quality improvement as it showed a decreasing (-) tendency of RTWQI. A comparison between RTWQI and the living environment standard of T-P showed that the categories of “completely coincident” and “different by one grade” accounted for 45% of the total, and the water quality of major tributaries was assessed as low. Therefore, the RTWQI, which applies comprehensive water quality parameters and has higher reliability than assessing a single water quality parameter, was determined to be efficient for water quality assessment of the major tributaries of the Namhan River.

In this study, the water quality components (pH, BOD, COD, TOC, SS, DO, TP) and the water quality, observed for 10 years (2008~2017) in the five tributaries of the Nakdong River with the highest flow rates, were analyzed. Monthly levels of the water quality components were estimated and regression functions were used to quantitatively explain the changes in the BOD and COD components, with respect to the TOC components. The results of analyzing the water quality levels in terms of the living environmental standards show that the lowest water quality was observed midstream (ST-3) and the highest water quality was observed upstream (ST-1 and ST-2). The regression function was estimated to be a linear function in all five tributaries, and the goodness of fit of the function was high upstream (ST-2), midstream (ST-3), and downstream (ST-4). According to the regression analysis using the observation data from 2008~2017, we found that the consumption of dissolved oxygen increased with an increase in organic matter in the major tributaries of the Nakdong River.

Water quality in Nakdong river was analyzed using 699 monitoring data sets including flow rates and water quality concentrations collected at 195 tributary monitoring stations (the priority management areas: 35 stations, the non-priority management areas: 160 stations) in 2015. The highest average concentrations of all data for BOD, COD, T-N, T-P, SS, and TOC were 30 600 times higher than the lowest concentrations while the highest average loading rates were 800,000 2,700,000 times higher than the lowest loading rates. Because of the very large differences in the concentrations and loading rates, the variation of the concentrations and loading rates in a priority management monitoring station for BOD, T-P, and TOC was analyzed using the coefficient of variation, the ratio of the standard deviation value to the mean value. For BOD, T-P, and TOC, the coefficients of variation for concentration were mostly less than 100%, whereas the coefficients of variation for loading rate ranged from 31.1% to 232.2%. The very big difference in the loading rates was due to the large variation in flow rates. As a result of this, the estimation of water quality at each monitoring station using the average values of the concentrations and loading rates might be not rational in terms of their representativeness. In this study, new water quality analysis methods using all collected monitoring data were suggested and applied according to the water quality standard in medium-sized management areas.

수은은 환경에서 자연적으로 발생하는 중금속이다. 무기 수은의 상당량은 주로 광물, 광산, 산업 폐기물 등의 인위적인 원천에서 습식 및 건식 대기 증착을 통해 수생 시스템을 들어가게 된다. 대체로 물가의 바닥에 사는 박테리아에 의해 무기물의 수은 메틸화 반응은 수중 먹이 사슬에 있는 생물들에게 농축이 된다. 높은 농도의 수은과 메틸수은에 노출 될 때 인체에 미치는 영향은 신경과 생식의 죽음에 이르기 까지 하여 큰 국제적 문제를 일으킨다. 최근 철강 산업 도시인 포항의 형산강, 구무천, 칠성천의 재첩과 퇴적물에서 높은 수은 농도가 검출 되었다고 보고되었다. 구무천과 칠성천은 포항 산업 단지를 포함하고 있고 형산강으로 합류되는 하천임을 보았을 때, 두 개의 강에서 수은 오염에 산업 폐수의 영향과 형산강과 연관이 있는지 알아보기 위한 연구는 필수적이다. 따라서, 이 예비 연구의 목적은 형산강, 구무천, 칠성천에서 수집 된 퇴적물의 총 수은과 메틸수은 농도를 조사 하는 것이다.

In this study, we analyzed on-site monitoring data for 15 tributaries in Geumho watersheds for 3 years (2011-2013) in order to sort out priorities on water quality characteristics and improvement. As a result of estimating contribution to contamination of the tributary rivers, Dalseocheon showed the highest load densities, despite the smallest watershed area, with 22.7% BOD5, 30.7% CODMn, 31.3% TOC and 47.6% TP. After conducting PCA (principal component analysis) and FA (factor analysis) to analyze water quality characteristics of the tributary rivers, the first factor was classified as CODMn, TOC, EC, TP and BOD5, the second factor as pH, Chl-a and DO, the third factor as water temperature and TN, and the fourth factor as SS and surface flow. In addition, arithmetical sum of each factor’s scores based on grading criteria revealed that Dalseocheon and Namcheon were classified into Group A for their highest scores - 96 and 93, respectively -, and selected as rivers that require water environmental management measures the most. Also, water environmental contamination inspection showed that Palgeocheon had the most number of aquatic factors to be controlled: BOD5, CODMn, SS, TOC, T-P, Chl-a, etc.

The objective of study was to analyze seasonal and inter-annual patterns of water chemistry of Miho Stream watershed during 2004 - 2007 along with some influences of tributaries and summer monsoon on the stream water quality. For the study, eight physico-chemical parameters such as nitrogen, phosphorus, BOD, COD and chlorophyll-a (CHL) etc. were analyzed in relation to spatial and temporal variability of seven sampling sites of the mainstream and some tributaries in the watershed. In the upstream reach, Mean of BOD, COD and TP averaged 3.2 mg/L, 6.5 mg/L and 186 μg/L, respectively, indicating an eutrophic conditions as a III-rank in the stream water quality criteria from the Ministry of Environment, Korea(MEK). The eutrophic water was due to a combined effect of Chiljang tributary with high nutrients (TP=844 μg/L, TN=8.087 mg/L) and the point sources from some wastewater treatment plants. In the meantime, BOD, TN, and TP in the downstream reach were about > 1.2-1.5 folds than the values of the midstream reaches. This was mainly attributed to effluents of nutrient rich-water (mean TN: 11.980 mg/L) from two tributaries of Musim Stream and Suknam Stream, which is directly influenced by nearby wastewater disposal plants. Seasonal analysis of water chemistry showed that summer monsoon rainfall was one of the important factors influencing the water quality, and water quality had a large spatial heterogeneity during the rainfall period. In the premonsoon, BOD in the downstream averaged 6.0±2.47 mg/L, which was 1.4-fold greater than the mean of upstream reach. Mean of CHL-a as an indicator of primary productivity in the water body, was > 2.2 - 2.9 fold in the downstream than in the upstream, and this was a result of the high phosphorus loading from the watershed. Overall, our data suggest that some nutrient controls in point-source tributary streams are required for efficient water quality management of Miho Stream.

Investigation was carried out to observe the dominant bacteria and the effect of metals(Cd & Zn) and its nitrate compound on growth of bacteria isolated from the three tributaries and lower reach of the Nakdong River. Mean CFU(log10) level was highest in Kumho River(8.30 CFU), Nam River, Hwang River, and Mulgum followed. Staphylococcus xylosus, Staph. lentus, Pasteurella pneumotropica, Aeromonas hydrophilla were dominant species in each study site. Cadmium powder and Zinc powder showed strong effect to inhibit the growth of Micrococcus spp., Pasteurella pneumotropica, Aeromonas hydrophilla. But, nitrate compounds of Cd and Zn(Cd(NO3)24H2O, Zn(NO3)26H2O) did not clearly show the strong effect to inhibit the growth of dominants.

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 concentration of Kumho River was vary high, average 1.0 ㎎P/ℓ. The other rivers were the range 0.05∼0.15 ㎎P/ℓ. Total nitrogen concentration of Kumho River was vary high, average 6.27 ㎎N/ℓ. The other rivers were the range 1.5∼3.0 ㎎N/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 % 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(Kangjung) and Kumho River accounted for 50 % and 30% of total loading, 25,959 tN/yr, respectively.