Understanding the characteristics of reservoir water quality is fundamental in reservoir ecosystem management. The water quality of reservoirs is affected by various factors including hydro-morphology of reservoirs, land use/cover, and human activities in their catchments. In this study, we classified 83 major reservoirs in South Korea based on nine physicochemical factors (pH, dissolved oxygen, chemical oxygen demand, total suspended solid, total nitrogen, total phosphorus, total organic carbon, electric conductivity, and chlorophyll-a) measured for five years (2015~2019). Study reservoirs were classified into five main clusters through hierarchical cluster analysis. Each cluster reflected differences in the water quality of reservoirs as well as hydromorphological variables such as elevation, catchment area, full water level, and full storage. In particular, water quality condition was low at a low elevation with large reservoirs representing cluster I. In the comparison of eutrophication status in major reservoirs in South Korea using the Korean trophic state index, in some reservoirs including cluster IV composed of lagoons, the eutrophication was improved compared to 2004~2008. However, eutrophication status has been more impaired in most agricultural reservoirs in clusters I, III, and V than past. Therefore, more attention is needed to improve the water quality of these reservoirs.

빈번한 가뭄의 피해는 수자원의 양극화를 초래하고 있다. 국내에서는 2011년부터 2017년 사이에 국지적이고 주 기적인 이상 가뭄이 지속되어 10년 가뭄 빈도로 설계된 소규모 저수지의 저수율이 감소하였다. 이러한 저수율의 감소 는 수질을 떨어트릴 수 있고 이미 확보된 용수의 사용마저 제한할 수 있다. 따라서 가뭄에 대비하고 극복하기 위해서 는 수질관리와 가뭄 빈도의 재산정이 필요하다. 이 연구는 저수지에서 수질 변화의 원인인 잠재적 오염물질을 추정하고, 가뭄 기간 동안 저수지의 저수율 감소와 그에 따른 수질 변화를 검토한 것이다.

Euiam and Paldang Reservoirs have often been facing water quality problems, such as eutrophication, algal blooms and off-flavors by treated wastewater effluent (TWE) in the North-Han and the Han River basins, but little is examined on the direct biological effect of TWE. This study tested algal growth potential (AGP) of four TWEs discharged into Euiam and Paldang Reservoirs to evaluate water fertility in September 2014 and March and September 2015. Test alga was used Anabaena circinalis isolated from Paldang Reservoir. Mean concentration of T-N and T-P in TWEs was 3,956.7 μg N L-1 and 50.8 μg P L-1, and the proportion of NO3-N and PO4-P to the total fraction was 72.1% and 40.8%, respectively. Both N and P were high in TWEs, but much higher N than P concentration indicates strong P-limitation. As a consequence, the maximum AGP was determined by PO4-P concentration (r=0.998, p<0.01). Mean AGP value was 15.4 mg dw L-1 among four effluents indicating its eutrophic condition. Due to the establishment of tertiary (advanced T-P) treatment method in the studied plants recently, P concentration was significantly decreased in TWEs compared to the years prior to 2012. However, P concentration seems to be still high enough to cause eutrophication and algal blooms. Therefore, wastewater treatment to P-free level needs to be considered if effluents are directly discharged into the drinking water resources.

This study deals with optimized structural analysis of stainless rectangular water reservoirs with 5,000ton capacity for various combined load cases. The objective of this study is to propose most efficient structural models through the comparison of various model cases. In order to perform an optimized analysis, three dimensional finite element analyses are carried out for large sized models. The numerical results obtained provides the detailed size and thickness for optimal design of water reservoir. In particular, results reported in this paper show the influence of various types of loading and dimensions of the wall and stiffened column on the structural behavior of the large sized water tanks.

The objective of this study was to determine temporal patterns and longitudinal gradients of water chemistry at eight artificial reservoirs and ten streams within the Han-River watershed along the main axis of the headwaters to the downstreams during 2009-2010. Also, we evaluated chemical relations and their variations among major trophic variables such as total nitrogen (TN), total phosphorus (TP), and chlorophyll-a (CHL-a) and determined intense summer monsoon and annual precipitation effects on algal growth using empirical regression model. Stream water quality of TN, TP, and other parameters degradated toward the downstreams, and especially was largely impacted by point-sources of wastewater disposal plants near Jungrang Stream. In contrast, summer river runoff and rainwater improved the stream water quality of TP, TN, and ionic contents, measured as conductivity (EC) in the downstream reach. Empirical linear regression models of log-transformed CHL-a against log-transformed TN, TP, and TN:TP mass ratios in five reservoirs indicated that the variation of TP accounted 33.8% (R2=0.338, p<0.001, slope=0.710) in the variation of CHL-a and the variation of TN accounted only 21.4% (R2=0.214, p<0.001) in the CHL-a. Overall, our study suggests that, primary productions, estimated as CHL-a, were more determined by ambient phosphorus loading rather than nitrogen in the lentic systems of artificial reservoirs, and the stream water quality as lotic ecosystems were more influenced by a point-source locations of tributary streams and intense seasonal rainfall rather than a presence of artificial dam reservoirs along the main axis of the watershed.

본 연구에서는 2011년 우리나라 10개의 중대형 인공호에서 배스의 우점도에 의한 외래종 영향 및 이에 대 한 어류 군집 구조 분석을 실시하였고, 이들이 출현하는 호수에 대한 이화학적 수질특성을 분석하였다. 10개 인공호에서 출현한 어류는 13과 52종이었으며, 배스의 상대 풍부도는 전체 어종들 중 13%를 차지하여, 출현한 어류들 중 3번째로 높게 우점하는 것으로 나타났다. 이런 결과는 향후 배스가 수체내에서 최상위 포식자로서의 포식압 및 생태적 지위 특성 때문에 많은 인공호들에서는 본 배스의 외래종 번성에 의한 생태계 교란 효과가 극대화 될 수 있음을 제시하였다. 전체 조사 대상 인공호들 중 평택호에서 배스의 상대 풍부도는 60%로서 가장 높게 나타난 반면, 대청호에서 풍부도는 3%로서 가장 낮게 나타났다. 배스 서식지에 대한 이∙화학적 수질분석 결과에 따르면, COD는 평균 4.5±2.5 mg L-1 였고, 총인 (TP) 농도는 0.058±0.047 mg L-1, 총질소 (TN)는 2.2±1.4 mg L-1로 나타났다. 인(P)과 질소(N) 의 농도 분석에 따르면, 평택호, 낙동강하구언, 주남저수지 등의 수체는 부영양화 현상이 높은 것으로 나타났다. 배스의 상대풍부도와 수질자료의 비교분석에 따르면, 두 변수는 통계학적으로 유의한 상관관계 (p.0.05)를 보이지 않았다. 즉, 배스의 분포 및 풍부도 특성은 이 화학적 수질도 중요하겠지만, 이들보다는 여러 타 요인들, 즉, 물리적 서식지 특성, 이용 가능한 먹이양 및 경쟁생물의 밀도 등에 의해 더 영향 받을 것으로 추정되었다.

우리나라 저수지에서 호안 환경의 특성을 파악하기 위 하여, 수위변동폭과 이용 목적에 따라서 35개 저수지를 선정하여 지형, 수문, 수질 및 토양 환경요인을 조사하여 이들 사이의 관계를 분석하고 환경 특성에 따라 저수지 의 유형을 구분하였다. 저수지의 지형적, 수문적 특성은 그 조성된 곳의 환경과 크기에 따라서 다양하였다. 저수 지의 연수위변동폭은 1~27 m로서 변이가 컸다. 저수지 의 수질은 대부분 중영양 혹은 부영양 상태이었다. 호안 의 토양 환경은 모래 함량이 많았다. 저수지의 수위변동 폭, 빈도 및 기간은 저수지의 이용 목적에 따라서 독특한 특성을 보였다. 홍수조절용 저수지는 수위변동 폭이 크고 빈도는 낮았으며 수력발전용 저수지는 수위변동 폭이 크 고 빈도가 높았다. 회귀분류 나무(CART) 분석 결과에 의 하면 저수지의 수질은 수심, 수위변동폭 및 고도에 의하 여 구분되었다. 주요인분석(PCA)의 결과에 의하면 환경 요인에 의하면 저수지의 유형은 저수지의 크기, 수위변동 폭, 수질 및 토양의 토성과 유기물 함량에 의하여 구분되 었다. 이상의 결과를 종합하면, 우리나라 저수지의 호안 에서 저수지의 크기, 수위변동폭, 수질 및 호안 토양의 특 성이 중요한 환경요인인 것으로 판단되었다.

본 조사에서 확인된 관속식물상은 98과 310속 402종 52 변종 7품종 1아종 462종류로 확인되었다. 한반도 고유종은 국립생물자원관(2011)이 지정한 한반도고유종은 눈주목, 외대으아리 및 할미밀망 등 총 10종류가 확인되었다. 식물 구계학적 식물종은 Ⅴ등급 종은 목련과 왕벚나무로 2종, Ⅳ등급종은 산복사, 측백나무 및 꽃창포 등 3종, Ⅲ등급종 은 단풍나무, 탱자나무 및 노각나무 등 3종, Ⅱ등급 종은 석창포, 주목 및 개고사리 등 3종 그리고 Ⅰ등급 종은 이팝 나무, 회양목 및 거지덩굴 등 8종이 확인되었다. 전주지역 소류지 7곳에서 부유식물은 개구리밥과 좀개구리밥으로 2 분류군, 부엽식물은 마름, 애기마름 및 가는가래 등 6분류 군, 침수식물은 말즘과 물수세미로 2분류군 그리고 정수식 물은 고마리, 왕버들 및 논냉이 등 총 52분류군이 확인되었 다. 귀화식물종은 총 45종류로 국화과가 노랑코스모스, 미 국가막사리, 실망초 및 개망초 등 16종으로 가장 많았고, 다음은 벼과로 메귀리, 큰김의털 및 들묵새 등 7종이, 메꽃 과 4종, 현삼과 3종, 마디풀과, 명아주과, 십자화과, 콩과 및 바늘꽃과는 각 2종 그리고 자리공과, 석죽과, 비름과, 대극과 및 소태나무과 등은 각 1종씩 확인되었다. 환경부 생태계교란식물은 돼지풀, 털물참새피와 물참새피 3종류가 출현하였다. 수질은 COD 기준으로 10이 초과되는 소류지 는 구주제가 16.23, 성곡제 14.59, 황학제 13.79 및 오송제 10.66으로 매우 나쁜 상태를 보였으며, 10이하인 소류지는 지사제 9.48과 서은제 8.65로 나쁜 상태이며, 학소제만 4.74 로 보통상태였다. 소류지 생태공원 이용실태 응답자의 50% 이상이 주 2회 이하로 방문하는 것으로 응답하였으며 생태 공원을 이용함에 있어 가장 큰 이점이 약 50%의 응답자가 스트레스 해소 및 생활 활력의 증가를 꼽았다. 탐방객 중 한 부류는 위락, 편의시설이 잘 구비된 곳보다는 불편하더 라도 한적한 곳을 찾고 싶다는 응답자가 50%를 넘었다.

This study was carried out to comparatively identify characteristics of turbid water influence in Imha Reservoir, Soyang Reservoir, and Daecheong Reservoir in Korea. We used 3 years dataset from 2002 to 2004 and analyzed seasonal water quality characteristics, particular parameters in association with turbidity, and light transparency to figure out the trends. All parameters to be used in the study were total phosphate (TP), total nitrogen (TN), chlorophyll-a (Chl), suspended solids (SS), Secchi depth (SD), conductivity, and vertical light extinction coefficienct (Kd), euphotic zone (Zeu), and critical depth (Zp). All parameters depend on season and watershed. Suspended solids from Soyang Reservoir were usually caused by TP, mainly related to living wastes and agricultures in upper stream. Daecheong Reservoir was influenced by organic matters related to large phytoplankton biomass in summer and inorganic suspended solids by nutrients in the winter. However, in case of Imha Reservoir, turbid water, consisted in silt and clay through heavy precipitation remained in the waterbody to decrease water transparency along with TP and caused the light limitation in winter. Overall results suggest that it was necessary to establish various management programs because the reasons occurring turbidity were varied according to the reservoir circumstances.

This study analyzed the temporal and spatial characteristics of water quality for five hydropower dam reservoirs in South Korea. Water temperature, pH, dissolved oxygen, and chlorophyll-a (Chl-a) showed high fluctuations in summer and autumn at all reservoirs, indicating the existence of seasonal effects. At all five reservoirs, the concentrations of suspended solids (SS) and total nitrogen (TN) fell under the “slightly bad” category and those of total organic carbon (TOC) fell under the “slightly good” category or higher, according to “the standard for living environment of lake water quality.” Variations in the concentration ranges and degrees of change in SS, TN, and TOC among reservoirs were observed, indicating the influences of rainfall, surrounding environments, and seasonal changes. Daecheong and Namgang Dam showed high Chl-a concentrations in summer, indicating that the metabolism of microbial communities, such as algae, was active.

This study developed the prototype of the system and implemented its main functions, which is the intelligent integrated agricultural water management information system and service (IaWAMISS). The developed system was designed to be able to collect, process and analyze the agricultural water information of spatially dispersed reservoirs in whole country and spatial geographic information distributed in various systems of other organizations. The system, IaWAMISS, is also possible to provide the reproduced information services in each reservoir and space units, such as agricultural water demand and supply analysis and drought prediction, to the people, experts, and policy makers. This study defined the 6 step modules to develop the system, which are to design the components of intelligent integrated information system, to derive the utilization contents of existing systems, to design the new development elements for IaWAMISS, to design the reservoir information system can be used by managers of city and county, to designate the monitoring reservoirs managed by city and county, and finally to prepare the sharing system between organizations with the existing information systems. In order to implement the prototype of the system, this study shows the results for three important functions of the system: spatial integration of reservoirs' information, data link integration between the existing systems, and intelligent analysis program development to assist decision support for agricultural water management. For the spatial integration with the reservoir water information of the Korea Rural Community Corporation, this study get IaWAMISS to receive the real-time reservoir storage information from the measurement facility installed in the municipal management reservoir. The data link integration connecting databases of the existing systems, was implemented by integrating the meteorological information of the Korea Meteorological Administration with IaWAMISS, so that the rainfall forecast data could be derived and used. For the implementation of the intelligent analysis program, this study also showed the results of analysis and prediction of agricultural water demand and supply amount, estimation of Palmer drought index, analysis of flood risk area in typhoon course region, and analysis of the storage status of reservoirs related to each storm. This study confirmed the possibility and efficiency of an useful system development through the prototype design and implementation of IaWAMISS. By solving the preliminary 6 step modules presented in this study, it is possible not only to efficiently manage water by spatial unit, but also to provide the service of information and to enhance the relevant policy and national understanding to the people.