Phytoplankton community is one of the important factors for the management of aquatic environment due to generation of varying toxins by harmful algal species. This study was performed to examine the phytoplankton community structure (PCS) in the midstream of Geum River (GR) from January 2014 to December 2015. The water sampling was performed in five stations on 2014, and three stations on 2015. Subsequently, the morphological identification was performed by microscopic observation in laboratory condition. As results, total 265 species were identified and it was comprised of 40.8% of Bacillariophyceae, 9.1% of Cyanophyceae, 44.5% of Chlorophyceae, and the others (4.9%). During the investigation period, total average standing crop of phytoplankton was 12,948 cells mL-1, and it was comprised of 7,702 cells mL-1 of Bacillariophyceae, 2,821 cells mL-1 of Cyanophyceae, 2,121 cells mL-1 of Chlorophyceae, and 305 cells mL-1 of others. To verify which tributaries of upstream area influence on PCS of midstream of GR, the phytoplankton standing crops of two stations including Mihocheon (MH) and Gapcheon (GC) were examined on 2014, and compared to result of on 2015. The results were shown that the MH station had more similar phytoplankton standing crops with midstream of GR than GC station. The relationship between environmental parameters and phytoplankton dynamics was studied at the investigated station. As results, whereas water temperature and total phosphorus were represented the positive correlation, N/P ratio was remarkably exhibited negative correlation. From the results, it is suggested that the PCS of midstream of GR was more affected by MH station than GC station, and the changes of temperature, phosphorus concentration, and N/P ratio may be important factors on the PCS formation of midstream of GR.

본 연구에서는 낙동강의 상주보에서부터 합천창녕보까지의 8개에 보에 대해 2011년부터 2013년 까지의 수온, 적산일사량, 영양염 농도, 식물플랑크톤 군집분포, 기타 수질조사 결과를 이용하여 식물플랑크톤 우점종의 천이특성과 수온과의 상관성, 우점종 상호 간의 영향 등에 대해 고찰하였다. 8개 보 단위의 별 우점종 평가에 있어 총 25개 종이 우점하고 있었다. 봄철에 대발생하는 Stephanodiscus sp.는 우점빈도가 39.4%로서 가장 높았으며 현존량 우점율은 58.6%였다. 여름철에 대발생하는 Microcystis sp.의 우점빈도는 8.5%였고 현존량 우점율은 36.6%였다. 8개 조사지점의 수온차이는 평균 1.83℃로서 지점별 차이는 통계적으로 유의하지 않았다. 분석 대상 우점종 중 수온과 음의 상관성을 보인 것은 Stephanodiscus sp. 1개 종(r=-0.26, p<0.01)이었으며 나머지 7개 종은 양의 상관성이 유의하게 나타냈다(r=0.08~0.28). Stephanodiscus sp.는 2∼18℃의 수온범위에서 높은 개체밀도를 보였고 2℃ 이하에서는 2,000cells ml-1 이하의 적은 개체밀도를 보였다. Stephanodiscus sp.의 봄철 수화현상 다음에 우점하는 종은 Aulacoseira granulata, Fragilaria crotonensis, Cyclotella sp. 등이었으며, Microcystis sp.는 Stephanodiscus sp.의 개체밀도가 감소되는 18℃ 정도에서 개체수 증가속도가 높아졌으며, 수온이 25℃ 이상이 되면 10,000cells mL-1를 초과하기 시작하고 28℃ 이상에서부터 현저하게 증가하여 수화현상이 나타났다. 낙동강에서 광범위한 수온 영역에 적응하고 있는 종은 Cyclotella sp., Aulacoseira granulata, Fragilaria crotonensis 등이었다. 적산일사량과 유의한 상관성을 보인 것은 Aulacoseira granulata 1개 종이었다. Stephanodiscus sp.는 분석대상 우점종 중에 Aulacoseira granulata 및 Aphanizomenon flos-aquae 종과의 상관계수가 각각 -0.12 및 -0.09로서(p<0.05) 음의 상관성이 유의하게 나타났다. Stephanodiscus sp.는 동물성플랑크톤의 요각류 (r=-0.11, p<0.01), 지각류 (r=-0.09, p<0.05) 등과 음이 상관성이 유의하게 나타났다. 따라서 Stephanodiscus sp.는 낙동강에서 동물성플랑크톤의 중요한 섭식원이 되고 있을 것으로 추정된다. 여름철 최대 우점종인 Microcystis sp.는 음의 상관성을 나타낸 다른 우점종은 없었다.

유기오염 및 부영양화 제어를 위한 생태공학적 오염 하천 정화기술의 하나로서 사상성 부착조류(Filamentous periphyton, FP)의 적용성 및 이용가능성을 검토하였다. FP의 증식도는 매질의 종류, 설치방법, 공극, 유속, 수온 및 수중 영양염의 농도에 따라 큰 차이를 보였다. 가장 높은 FP의 증식도를 보이는 조건은 유속 10 cm/s 내외, 수류방향에 수직으로 수직으로 설치된 4 mm 망목의 그믈망 매질이었으며 같은 물리적 조건에서는 유입수의 인농도에 따라 증식도가 커졌다. 유입수 인산염 인농도가 0.025~0.075 mgP/L, 유속이 5~15 cm/s의 조건에서 Pilot 인공수로(40 cm폭×25 cm깊이×20m길이)내 FP의 순생산성은 74~125 mgChl-am-2d-1, 비증식속도는 0.42 ~0.46/d, 인제거율은 19~103 mgPm-2hr-1, 조체당 비제 거율은 62~196 mgPgChl-a-1hr-1였으며 유입수의 인농도와 유속의 증가시 인제거율은 함께 증가하였다. FP가 정상적으로 착상된 상태에서 유입수의 농도대비 인제거 효율은 약 45% 내외였다. 과영양 하천인 경안천의 현장수로내 부착조류량은 최고 1,168 mgChl-a/m2에 달하였으며 접종 후 2주간 부착물의 증가속도는 20gDWm-2d-1, FP의 순생산성은 83mgChl-am-2d-1, FP의 비증식속도는 0.36/d였다. 접종한지 1주일 이후의 평균 용존산소 증가율은 7.7 gO2m-2 hr-1였으며 물질제거율은 BOD5가 4.4 gO2m-2hr-1, 총질소는 1.7 gNm-2hr-1, 총인과 인산염인은 각각 278, 85 mgPm-2hr-1였다. 부착물의 건조중량 당 비제거율은 총 인이 1,252 μgPgDW-1hr-1, 인산염인이 376 μgPgDW-1hr-1 였다. 인제거율은 FP의 양에 따라 함께 증가하였으며 FP 시스템에서의 인의 제거는 인산염인의 흡수, 유기성 인의 침전과 흡착 및 분해, 재흡수의 복합과정에 의한 것임을 시사하였다. FP 성장시 인이 조류생장에 대한 제 한요인으로 작용하여 유출수의 질소/인 비는 유입수에 비해 현저히 높았다. 이는 FP 시스템이 영양물질의 제거 뿐만 아니라 그 조성비를 변화시키므로써 수환경의 변화를 유발할 수 있음을 시사하는 것이다. 이상의 결과에서 FP 시스템은 수생관속식물에 비해 20~40배의 영양염류 제거율을 가지므로 하천수의 직접정화에 매우 효율일 것으로 판단된다. 그러나 FP는 증식속도가 빠르므로 매질의 폐쇄를 억제하기 위한 노화 식물체의 관리, 효율증대를 위한 매질의 선별과 설치 방법, 시스템내 미소생태계의 변화 등 지속적인 연구가 계속되어야 할 것이다. 유기물과 영양염이 모두 고농도 인 오염하천의 경우 유기물 제거를 위한 생물막과 영양 염 제거를 위한 FP 시스템을 연결한 복합시스템도 고안 할 수 있을 것이다.

Ministry of Environment has been operating water quality monitoring network in order to obtain the basic data for the water environment policies and comprehensively understand the water quality status of public water bodies such as rivers and lakes. The observed water quality data is very important to analyze by applying statistical methods because there are seasonal fluctuations. Typically, monthly water quality data has to analyze that the transition comprise a periodicity since the change has the periodicity according to the change of seasons. In this study, trends, SOM and RDA analysis were performed at the Mulgeum station using water quality data for temperature, BOD, COD, pH, SS, T-N, T-P, Chl-a and Colon-bacterium observed from 1989 to 2013 in the Nakdong River. As a result of trends, SOM and RDA, the Mulgeum station was found that the water quality is improved, but caution is required in order to ensure safe water supply because concentrations in water quality were higher in the early spring(1~3 month) the most.

The government has conducted a plan of total maximum daily loads(TMDL), which divides with unit watershed, for management of stable water quality target by setting the permitted total amount of the pollutant. In this study, BOD concentration trends over the last 10 years from 2005 to 2014 were analyzed in the Geumho river. Improvement effect of water quality throughout the implementation period of TMDL was evaluated using the seasonal Mann-Kendall test and a LOWESS(locally weighted scatter plot smoother) smooth. As a study result of the seasonal Mann-Kendall test and the LOWESS smooth, BOD concentration in the Geumho river appeared to have been reduced or held at a constant. As a result of quantitatively analysis for BOD concentration with exploratory data analysis(EDA), the mean and the median of BOD concentration appeared in the order of GH8 〉GH7 〉GH6 〉GH5 〉GH4 〉GH3 〉GH2 〉GH1. The monthly average concentration of BOD appeared in the order of Apr 〉Mar 〉Feb 〉May 〉Jun 〉Jul 〉Jan 〉Aug 〉Sep 〉Dec 〉Nov 〉Oct. As a result of the outlier, its value was the most frequent in February, which is estimated 1.5 times more than July, and was smallest frequent in July. The outlier in terms of water quality management is necessary in order to establish a management plan for the contaminants in watershed.

As a result of analysis based on the observed data for BOD, COD and TOC in order to manage non-biodegradable organics in the Geumho River, COD/BOD ratio was analyzed as the occupying predominance proportion. In this study, the classification(changes in water quality measurement : increase, equal, decrease) and measurement of BOD and COD were analyzed for trends over the past 10 years from 2005 to 2014 in the Geumho River. The Geumho River is expected to need non-biodegradable organics management because BOD was found to be reduced 61.1% and COD was found to be increased 50%. As a result of the analysis of land use, the Geumho-A is a unit watershed area of 921.13 km2, which is the most common area that is occupied by forests. The Geumho-B is a unit watershed area of 436.8 km2, which is the area that is highest occupied by agriculture and grass of 24.84%. The Geumho-C is a unit watershed area of 704.56 km2 accounted for 40.29% of the entire watershed, which is the area that is occupied by urban of 15.12%. Load of non-biodegradable organics, which is not easy biodegradable according to the discharge, appeared to be increased because flow coefficient of COD and TOC at the Geumho-B were estimated larger than 1 value. The management of non-point sources of agricultural land is required because the Geumho-B watershed area occupied by the high proportion of agriculture and field. In this segment it showed to increase the organics that biodegradation is difficult because the ratio of BOD and TOC was decreased rapidly from GR7 to GR8. Thus, countermeasures will be required for this.

In this study, it is an object to develop a regression model for the estimation of TOC (total organic carbon) concentration using investigated data for three years from 2010 to 2012 in the Gam Stream unit watershed, and applied in 2009 to verify the applicability of the regression model. TOC and CODMn (chemical oxygen demand) were appeared to be derived the highest correlation. TOC was significantly correlated with 5 variables including BOD (biological oxygen demand), discharge, SS (suspended solids), Chl-a (chlorophyll a) and TP (total phosphorus) of p<0.01. As a result of PCA (principal component analysis) and FA (factor analysis), COD, TOC, SS, discharge, BOD and TP have been classified as a first factor. TOCe concentration was estimated using the model developed as an independent variable BOD5 and CODMn. R squared value between TOC and measurement TOC is 0.745 and 0.822, respectively. The independent variable were added step by step while removing lower importance variable. Based on the developed optimal model, R squared value between measurement value and estimation value for TOC was 0.852. It was found that multiple independent variables might be a better the estimation of TOC concentration using the regression model equation(in a given sites).

The MFFn(Mass first flush), EMCs(Event mean concentrations) and runoff loads were analyzed for various rainy events(monitoring data from 2011 to 2012) in transportation area(rail road in station). The pollutant EMCs by volume of stormwater runoff showed the BOD5 9.6 ㎎/L, COD 29.9 ㎎/L, SS 16.7 ㎎/L, T-N 3.271 ㎎/L, T-P 0.269 ㎎/L in the transportation areas(Railroad in station). The average pollutant loading by unit area of stormwater runoff showed the BOD5 27.26 kg/㎢, COD 92.55 kg/㎢, SS 50.35 kg/㎢, T-N 10.13 kg/㎢ and T-P 10.13 kg/㎢ in the transportation areas. Estimated NCL-curve(Normalized cumulated-curve) was evaluated by comparison with observed MFFn. MFFn was estimated by varying n-value from 10% to 90% on the rainy events. The n-value increases, MFFn is closed to '1'. As time passed, the rainfall runoff was getting similar to ratio of pollutants accumulation. The result of a measure of the strength of the linear relationship between observed data and expected data under model was good.

본 연구에서는 기상청에서 제공하는 RCP 기후변화시나리오를 이용하여 기후변화와 유역유출특성에 따른 환경영향을 평가하였다. SWAT모형을 이용한 미래 댐 유입량 평가, HEC-ResSim 모형을 이용한 댐 안전성 평가 및 하류 유황분석을 수행하였다. 또한, 기존 수질관측자료를 이용하여 Seasonal-Kendall Test를 통해 수질변화 추세에 대해 분석하였고, SWAT과 HEC-ResSim 모형으로 도출된 방류량 및 지류유출량을 Qual2E모형에 적용하여 미래 수질변화 추세에 대해 분석하였다. 다음과 같은 유역 통합환경검토 기법은 하천환경에 대한 과학적 물환경 관리 체계를 확보하고, 기후변화 등 새로운 환경문제에 선제적으로 대응하기 위한 지침을 마련할 수 있을 것이다.

본 연구에서는 시간에 따른 수질 변화를 파악하고 원인에 따른 경향을 분석함으로써 적절한 관리대책을 수립하는 것이 필요 하다고 생각되어 이 같은 연구를 하게 되었다. 현재 수질오염이 심각한 낙동강 수계를 대상으로 2006～2010년까지 수질변화를 분석하였다. 수계의 803개, 국가하천 13개소, 지방1급 하천은 10개소, 하천에 합류하는 하천은 31개 지점에서 측정한 수은, BOD (Biological Oxygen Demand), TN (Total Nitrogen)과 TP (Total Phosphorus) 등의 월평균 자료결과를 바탕으로 하여 통계적분석(상관분석, 회귀분석, 분산분석, 시계열분석)을 통한낙동강유역의 인근 지역의 계절별로 수질항목을 확인하였으며, 평가지표에 따른 변화를 측정하고자 하였다. 유역의 지질 및 지형의 영향이 주로 작용하는데 지역의 기후 조건, 식생, 지형, 토양, 비 포화대 매질의 영향을 받기 때문에 여러 가지의 변수를 가지고 유출했으며, 이는 방류량의 결정문제, 호소의 부영양화 문제 등이 제기될 수 있겠으며, 좋은 개선방안을 만들어 보려고 한다. 따라서 낙동강의 강우기 유량을 증대하는 대책이 병행되는 것이 바람직하며, 물 관리대책에는 하천유지용수 확보를 구성을 해야 하며, 수로 건설사업 완료를 지속적인 관찰이 필요하다. 그러나 지류에는 물이 흐르지 않는 시기가 발생하는 이유는 자연 상태에서 흘러야 하는 하천수 및 공업용수와 농업용수로 취수했기 때문이다. 따라서 이 모든 것을 관찰 및 구성을 하기 위해서는 지속적인 연구가 필요로 하며, 다음과 같은 연구의 목적을 두고 연구조사 하였다.

This study analyzed the characteristics of stormwater runoff by rainfall type in orchard areas and transportation areas for 2 years(2010~2011year). Effluents were monitored to calculate the Event Mean Concentrations(EMCs) and runoff loads of each pollutant. The pollutant EMCs by volume of stormwater runoff showed the ranges of BOD 0.9~13.6 ㎎/L, COD 13.7~45.2 ㎎/L, SS 4.1~236.4 ㎎/L, T-N 2.123~21.111 ㎎/L, T-P 0.495~2.214 ㎎/L in the orchard areas, and was calculated as BOD 2.3~22.5㎎ /L, COD 4.4~91.1 ㎎/L, SS 4.3~138.3 ㎎/L, T-N 0.700~13.500 ㎎/L, T-P 0.082~1.345 ㎎/L in the transportation areas. The correlation coefficient of determination in the orchard area was investigated in the order of Total Rainfall(0.81) > Total Runoff(0.76) > Rainfall Intensity(0.56) > Rainfall Duration(0.46) > Antecedent Dry Days(0.27). Also, in the case of the transportation area was investigated in the order of Total Rainfall (0.55) > Total Runoff(0.54) > Rainfall Intensity(0.53) > Rainfall Duration(0.24) > Antecedent Dry Days(0.14). As the result, comparing valuables relating to runoff of non-pollutant source between orchard areas and transportation areas, orchard area(R2 ≥ 0.5 : X3, X4, X5) was investigated to have more influence of diverse independent valuables compared to the transportation area(R2 ≥ 0.5 : X3, X4) and the difference of discharge influence factor by the land characteristics appeared apparently.

Loading of NPS pollutant was valued through simulation by using BASINS/HSPF model which can simulate runoff volume in rainfall by time. For the verification of the model, it was analyzed the scatter diagram of the simulation value and measure value of water quality and runoff volume in Dongcheon estuary. Using the built model, a study on the time-variant characteristics of runoff and water quality was simulated by being classified into four cases. The result showed the simulation value was nearly same as that of the measured runoff. In the result of fit level test for measured value and simulated value, correlation of runoff volume was computed high by average 0.86 and in the water quality items, fit level of simulation and measurements was high by BOD 0.82, T-N 0.85 and T-P 0.79.