• 생태와환경
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• 제43권2호
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• pp.199-211
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• 2010

The objectives for this study were to evaluate spatial and temporal characteristics of water quality, based on long-term water quality monitoring data during 1993~2008. We found that physico-chemical and ecological conditions in the Daecheong Reservoir (DR) were modified by the construction of upper dam (i.e., Yongdam Reservoir). total phosphorus (TP), Secchi depth (SD), and chlorophyll-a (CHL) in the DR showed significant longitudinal decreases along the headwater-to-the downlake, indicating a large spatial variation, and this gradient was more intensified during the high-flow season (monsoon). Nutrient-rich water containing high nitrogen and phosphorus in the monsoon season (July~August) passed through the reservoir as a density current in the metalimnetic depth, and also high suspended solids increased in the metalimnetic depth, especially during the monsoon. According to the deviation analysis of Trophic State Index (TSI), >50% of TSI (CHL)-TSI (SD) and TSI (CHL)-TSI (TP) values were negatives, so that inorganic suspended solids (non-votatile solids) influenced the underwater light regime against phytoplankton growth. Also, ratios of CHL:TP after the dam construction evidently increased, compared to the values before the upper dam constructions, indicating a greater yield of phytoplankton in the unit phosphorus. Overall data showed that ecological and functional changes in Daecheong Reservoir occurred after the construction of upper dam (Yongdam Reservoir).

• 한국물환경학회지
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• 제33권3호
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• pp.341-347
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• 2017

From 2014 to 2016 water quality survey results according to the location and depth of Youngrang Lake are as follows: Distribution of dissolved oxygen in the water depth was investigated by the middle section and the downstream 1st, 3rd, 5th, when investigating bottem 1m interval anoxic layer. In organic matter and nutrient concentration distribution COD upstream 2.8 mg/L, middle section 4.2 mg/L downstream 4.1 mg/L, more than two times higher in bottem layer and TP concentrations showed a similar trend with COD, upstream of 0.047 mg/L, middle section was 0.051 mg/L, downstream of 0.059 mg/L. There was a difference in salinity every survey period the average salinity is lowest with 28.5‰ when the second survey. And the highest with 32.1‰ in the fourth investigation. Korean trophic state index($TSI_{KO}$) were showed eutrophic conditions in the middle section and downstream else showed mesotrophic state in the entire period. In order to evaluate the cause of water pollution Youngrang lake, regression analysis of the relationship between salinity and DO, COD, TN, TP, Chl-a results, $R^2$ is from 0.63 to 0.95 Youngrang lake water quality was found to have a close relationship with salinity due to inflow of seawater. As a result, in order to improve the quality of Youngrang lake efficient incorporation of the amount of water through the seawater influent as it is considered the key.

• 생태와환경
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• 제42권1호
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• pp.95-106
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• 2009

The Shihwa constructed wetland was established for the treatment of severely poluted water from Banwoul, Donghwa and Samhwa streams. This study was focused on investigating the structure of epiphytic diatom communities on reed (Phragmites communis) planting area at Banwoul high wetland (3 stations) and low wetland (3 stations) from March to October 2005. The concentration of T-N of inlet stations from the streams were decreased by flowed through the wetland, but the concentration of T-P were increased at outflow part. Epiphytic diatoms on the reed were a total 109 taxa which were composed of 103 species, 5 varieties, 1 unidentified species. The standing crops were rapidly decreasing tendency from spring to autumn but chlorophyll-a concentration were showed a very irregulated changes. Dominant species were 6 taxa which were Achnanthes minutissima in the early investigation, and were changed to the genus Navicula and the genus Nitzschia in the summer. DAIpo were ranged the values of $20.2{\sim}51$, which were mesosaprobic states at the high wetland and ranged the values of $12.4{\sim}52$, which were polysaprobic to mesosaprobic states at the low wetland. TDI were ranged the values of $28.8{\sim}94.5$, which were oligotrophic to eutrophic state at the high wetland and ranged the values of $33.3{\sim}89.7$ which were mesotrophic to eutrophic states at the low wetland. The healthy assessment (DAIpo and TDI) of water ecosystem were showed clean-bad from spring to autumn. These epiphytic diatom communities were determinated by the biological factor such as the growth of reed and the physical factors such as water temperature, light penetration and SS and so on.

• 환경영향평가
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• 제17권6호
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• pp.373-380
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• 2008

The Ministry of Environment plans to improve quality of water which is achieved over 85% in rivers and 94% in lakes of the whole country as "Good Water" until 2015. Also, the law of evaluation of water quality and water quality goal were made newly. So, the water quality has evaluated by using new law since 2007. This study evaluated whether "Good Water" and" Water Quality Goal" were achieved or not in 22 middle-sized districts and major 10 lakes of Geum river. The achievement rates of rivers decreased and the achievement rates of lakes mostly were the same for 5 years. In 2007, the achievement rates of "Good Water" were 50% in rivers and 50% in lakes. The achievement rate of "Water Quality Goal" were 59.1% in rivers and 20% in lakes. The water quality in 2007 was evaluated worse than last year in case of rivers. The evaluations of Korea-Comprehensive Water Quality Index(K-CWQI) showed that achievement rates of "Water Quality Goal" were 81.8% in rivers and 0% in lakes. The statistical correlation analysis showed that correlations between BOD and COD were meaningful at the downstream, compared to upstream, generally. In case of lakes, correlations between COD and temperature were meaningful. Also, correlations between COD and Chl-a were meaningful. The Trophic State Index ($TSI_{KO}$) showed that the half of lakes are major over eutrophic status in lakes. These analytical methods such as K-CWQI, $TSI_{KO}$, statistical correlation analysis could be additionally helpful for evaluation of water quality and provide basis data for understanding characteristics of watershed in Geum river.

• 환경영향평가
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• 제21권6호
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• pp.841-857
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• 2012

Preliminary ecological environmental assessments including physico-chemical constituents, water quality, fish fauna analysis, physical habitat health, and ecological health assessment were conducted as a primary step for Jeungchon micro-habitat ecosystem restoration in 2012. Water chemistry analysis of conductivity, dissolved oxygen, chlorophyll-a and etc. indicated that there were no significant differences(p < 0.05) among 6 sites between the headwaters and downstream. Multi-metric model analysis of Qualitative Habitat Evaluation Index(QHEI) showed that brooklets were at "good condition" as a mean QHEI of 158.7(n = 6) and the longitudinal differences of the model values between the sites were minor(QHEI range: 153 - 165). Total fish species and the number of individuals were 12 and 481, respectively, and dominant species were Zacco platypus(49.5%) and Zacco koreanus(36.8%). Tolerance guild analysis showed that the proportion of sensitive species($S_S$) had a negative linear function[$S_S=86.35-0.31(D_H)$; $R^2$ = 0.892, p < 0.01] with a distance from the headwaters, while the proportion of tolerant species($T_S$) had a positive linear function($R^2$ = 0.950, F = 90.28, p < 0.001) with the distance. Trophic feeding guild analysis showed that the proportion of insectivore species($I_n$) had a negative linear function($R^2$ = 0.934, p < 0.01) with a distance from the headwaters, while the proportion of omnivore species($O_m$) had a positive linear function($R^2$ = 0.958, p < 0.001) with the distance. Index of Biological Integrity(IBI) model, based on fish assemblages, showed a "fair condition" as a mean IBI of 23(n = 6), and there was a distinct differences of ecological health between the headwaters(S1 = 30; "good condition") and the downstreams(S6 = 14; "poor condition"). Overall, the preliminary environmental impact assessments suggest that water quality, physical habitat conditions(QHEI model), and ecological health(IBI model) were maintained well, even if the state was not an excellent conditions.

• 환경생물
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• 제31권4호
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• pp.440-447
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• 2013

본 연구에서는 남한강 상류수계의 10개 지점에서 생물보전지수 (Index of Biological Integrity, IBI) 및 물리적 서식지 평가 지수 (Qualitative Habitat Evaluation Index, QHEI)를 이용하여 생태건강도 특성을 평가하였다. 생물보전지수 조사는 Karr (1981)가 제시한 12개 항목 중 11개 메트릭에 대하여 평가하였다. 생물보전지수 등급은 "양호상태"였고, 지점별 IBI 값의 범위는 33 (악화상태)~47 (양호상태)로 나타났다. 물리적 서식지측면에서는 Plafkin et al. (1989)에 의해 도입된 서식지 평가 지수(QHEI)의 12항목 중 9개 항목에 대해 평가를 실시했으며, QHEI 값의 범위는 75~109로 나타났으며, 전체 서식지 건강도 평균치는 부분 지지상태(Partially supporting)로 나타났다. 연구지점내의 하천 비교평가에 따르면, Gj 하천의 IBI 모델 값 및 QHEI 모델 값은 타 하천들 (Ig, Dn 하천)에 비해 양호한 상태로 평가되었다. 어류의 영양단계 종 성분분석에 따르면, 식충종, 잡식종 및 육식종은 61.9%, 19.0% 및 9.5%를 차지하는 것으로 나타났다. 어류의 내성도 길드분석에 따르면, 민감종 (76.1%)은 내성종 (4.7%)보다 우점하여 생태계가 건전한 것으로 평가되었다. 서식지 길드 분석에 따르면, 여울성 저서종(57.1%)은 수층종(28.5%)보다 우점하는 것으로 나타났다. 연구기간 동안, 외래종 및 질병에 걸리거나 비정상적인 증상을 나타내는 개체는 관측되지 않았다. 전체적으로 생태건강도 모델값(IBI) 및 서식지평가지수 모델값의 분석에 따르면 본 상류 하천지역은 생태학적으로 양호한 상태로 잘 유지되는 것으로 평가되었다.

• 생태와환경
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• 제47권3호
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• pp.146-159
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• 2014

In this study, we evaluated the temporal changes of water quality in the 90 reservoirs in Korea and the relationships between water quality and their environmental factors in the reservoirs for effective management of reservoirs. The majority of study reservoirs were categorized as the eutrophic state based on Carlson's trophic index. Among 90 reservoirs, more than 55.0% were nutrient-rich based on $TSI_{TP}$ in each month, where more than 50.0% were nutrient-rich based on $TSI_{Chl-a}$ from June to November. Seasonal Mann-Kendall test was used to analyze temporal variation of water quality in the selected 60 reservoirs using monthly data from 2004 to 2008. The results showed that 27 (45.0%) reservoirs showed the improvement of water quality based on TP and Chl-a concentrations, while 14 (23.3%) and 11 (18.3%) reservoirs displayed the degradation of water quality based on TP and Chl-a concentrations, respectively. Meanwhile, a self-organizing map classified the study reservoirs into five groups based on differences of hydrogeomorphology (altitude, catchment area, bank height, lake age, etc.). Physicochemical factors and land use/cover types showed clear differences among groups. Finally, hydrogeomorphology of reservoirs were related to water quality, indicating that the hydrogeomorphological characters strongly affect water quality of reservoirs.

• 한국환경보건학회지
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• 제44권4호
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• pp.315-322
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• 2018

Objectives: A lake is a place used by many people, and compared to rivers it is easy for them to become polluted. The water quality in lakes and reservoirs has been worsening recently. The purpose of this study is to evaluate the water pollution characteristics of major lakes in northern Gyeonggi-do Province. Methods: Six lakes were selected as major lakes and were evaluated in terms of water pollution characteristics and eutrophication (as defined by results for $COD_{Mn}$, TOC, SS, Chl-a, T-N and T-P) over one year (from December 2016 through November 2017) in northern Gyeonggi-do Province. Results: The annual average $COD_{Mn}$ was found to be 3.1 mg/L in Onam, 3.6 mg/L in Sanjeong, 4.7 mg/L in Gisan, 4.8 mg/L in Ilsan, and 6.1 mg/L in Jangja. The results of the Korean trophic state index ($TSI_{KO}$ ) value indicated a eutrophic state ($TSI_{KO}$ 59.0) in Jangja lake. The other lakes were classified as being in a mesotrophic state ($TSI_{KO}$ of 38.1 in Sanjeong, 40.2 in Ilsan, 41.9 in Onam, 46.1 in Gisan, and 47.8 in Gomo). Conclusions: Ilsan Lake's water quality is being well maintained. Sanjeong, Onam, and Gisan are appropriate for use as agricultural water. Jangja lake requires efforts for water quality improvement and to prevent the inflow of non-point pollutant sources.

• 생태와환경
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• 제34권3호통권95호
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• pp.206-214
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• 2001

1998년부터 2000년까지 겨울 결빙기를 제외한 청초호의 수질 및 영양상태의 판정결과 부영양화가 심각한 것으로 조사되었다. 투명도는 0.4${\sim}$1.3 m로 비교적 낮은 값을 보였으며, COD농포는 전 조사지점에서 $3.0{\pm}1.0\;mgO_2/L$이었다. 염분은 $29.3{\pm}5.5\;ppt$로 매우 높았으며, 수심 약 0.5${\sim}$l.5 m에서 염분에 의한 화학성층(chemocline)이 형성되어 심층에 산소공급이 제한되었다. 또한 표층보다 심층수의 수온이 높은 수온역전현상이 관찰되기도 하였다. 표층수의 총인은 0.048${\sim}$0.253 mgP/L, 총질소는 0.9${\sim}$2.4 mgN/L의 범위로 나타났으며, 청초호에서의 TN/TP 비는 대체적으로 20 이하로 질소가 수중 생물의 성장과 생성에 제한 요소로 작용할수도 있음을 시사하였다. 그러나 일반적으로 인과 질소의 농도가 높게 유지되어 총질소와 총인의 비로서 제한 요소를 파악하는 것은 무리가 따르는 것으로 판단된다. 유입수가 유입되는 정점 1보다는 해수의 영향이 많은 연안으로 갈수록 점차 TN/TP비가 감소하여 해수의 영향이 클수록 인함량에 대한 질소함량비가 상대적으로 감소하는 것으로 사료된다. 조사기간 식물플랑크톤의 경우는 연중 녹조류인 Microspora sp.가 우점하였으며, 식물플랑크톤에의한 Chl. a값은 매년 감소하는 반면 부유물질의 농도는 점차 증가하여 무기현탁물의 부유물질에 대한 기여도가 점차 증가하고 있음을 알 수 있다. 청초호의 엽록소 a농도는 각 정점 평균 $14.0{\pm}25.0\;mg/m^3$으로 나타나 U.S.EPA 기준으로 볼 때 부영양호로 분류되며, 여름 성장기엽록소 a, 투명도,및 총인의 평균치를 이용한 부영양화도지수 (TSI)도 평균 59${\sim}$77로 부영양 상태로 나타났다.

• 환경영향평가
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• 제21권3호
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• pp.483-501
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• 2012

본 연구에서는 2005 - 2006년 기간 동안 국내 인공호의 환경영향평가를 위해 LEHA 다변수 생태모형(Lentic Ecosystem Health Assessment Model)을 청평호에 적용하였고, 생태 건강도 모델값을 산정하였다. LEHA 생태 평가모형은 생물학적 변수($B_p$), 물리적 변수($P_p$), 화학적 변수($C_p$)의 11개 주요 메트릭으로 구성되었고, 이를 통합하여 생태 건강도 등급을 평가하였다. 생물학적 변수($B_p$)는 수환경의 질적 저하에 따라서 감소하는 민감종 메트릭($M_2$, NSS) 및 충식종 메트릭($M_5$, % $I_n$)이 이용되었고, 두 메트릭 모델값은 각각 1.5%, 32.4%로서 낮게 나타났다. 반면, 내성종($M_3$, % $T_s$)과 잡식종 메트릭($M_4$, % $O_m$) 값은 43%, 62%로서 높게 나타나 호수생태계의 질적 저하가 확인되었다. 물리적 서식지 변수($P_p$)는 수변 식피율($M_9$, % $V_c$)로서 1차 조사에 비해 2차 조사에 높게 나타났으며, 상류에서 하류로 갈수록 메트릭 모델 값이 감소하는 것으로 나타났다. 이는 정수역의 증가로 서식환경의 단순화와 인근 수체에서 실시되고 있는 잦은 골재 채취로 인한 서식지의 하상구조 변경이 악영향을 준 것으로 사료되었다. 한편, 화학적 수질특성 변수($C_p$)는 수체의 이온(양이온/음이온) 특성을 나타내는 전기전도도($M_{10}$, $C_I$)와 부영양 상태를 평가하는 Chl-a의 부영양화 지수($M_{11}$, $TSI_{CHL}$)로서 메트릭 모델값은 계절별 변이는 크게 나타났고, 지점 간의 공간변이는 미미한 것으로 나타나, "양호상태"로 평가되었다. LEHA 다변수 모델에 의거한 청평호의 환경영향평가에 의하면, 생태 건강도 LEHA 모델값은 1차 조사에서 30.7로 "보통-악화상태", 2차 조사에서 28로 "악화상태"를 보여 계절 변이 특성을 보였다. 지점별 LEHA 모델값은 호수의 정수대(S5)에서 28로 최소치를 보였고, 그 외 지점들도 29 - 30으로 지점 간 미미한 차이를 보였다. 청평호의 종합적인 환경영향평가에 의하면, 이 화학적인 수질기준 측면에서는 "양호상태"를 보인 반면, 생물학적 기준에서는 "악화상태"를 보였는데, 이는 빈번한 준설작업으로 인한 물리적 서식지 교란이 영향을 준 것으로 사료되었다.