• Journal of the Korean Association of Geographic Information Studies
• /
• v.22 no.2
• /
• pp.107-120
• /
• 2019

In this study, the characteristics of watershed and pollution source were investigated in SoOakcheon located in the upper stream of Daecheong Lake. The Dimension Index method was applied to index various watershed and pollution source data. The influence factors of each pollutant source were derived through correlation analysis between selected index and water quality monitoring data. BOD and COD were significantly influenced by population density and land area ratio, T-N by CN and rice area ratio, and T-P by population density and land area ratio, respectively. The discharge load is often used to establish non-point source countermeasures, but there is a difference between the water load and the water load in the lake or river. Therefore, in order to manage non-point pollution efficiently, it is necessary to analyze influential factors with high correlation with water quality and to manage the relevant factors with priority.

• Journal of Environmental Impact Assessment
• /
• v.21 no.5
• /
• pp.617-629
• /
• 2012

This study aims to find out critical areas of a soil loss and propose feasible measures to reduce the water quality deterioration by a soil lose. As a study area, the So-ok stream catchment locating at the upper area of Daecheong Reservoir is selected and intensive field observation was carried out. RUSLE model is applied to assess the impact of the pollution migration by a soil ross from the critical areas during storms on the water quality of Chusori embayment. As results, total amount of the soil ross assessed against to the critical area on which major type of land use is a orchard for fruits is 54.3 ton/ha/yr and that of an abandoned mine site is about 200 ton/ha/year. In particular as effective measures, a plantation of an appropriate species of fruit trees and an application of ecologic restoration schemes are proposed against to the orchard and the abandoned mine site, respectively.

• Journal of Korean Society on Water Environment
• /
• v.20 no.6
• /
• pp.657-663
• /
• 2004

The aims of this study are the characterization of runoff from nonpoint source, the analysis of the pollutant loads and an establishment of a management plan for nonpoint source of Okcheon. For this purpose the basin of the stream So-okcheon was selected to the investigated. During the period from May 29 to July 21 in 2003, the water automatic sampler system has been installed in Okkagkyo and parameters such as SS, COD, TOC, TP and TN were analyzed. The pollutants of nonpoint source seem to be washed out along the stream water in the beginning of rainfall, remain in water and cause the stream pollution. The runoffs during heavy rainfall, especially, much higher concentration of SS than those during dry period. With respect to the annual loading of pollutants of the nonpoint source, the COD was 124 ton/yr, TOC 396 ton/yr, TN 1,429 ton/yr and TP 4.2 ton/yr in the year 2002. With respect to the pollutants loading of the nonpoint source, the COD was 375 ton/yr(95% of the total COD loading of 394 ton/yr), TOC 844 ton/yr(96% of the tatal TOC loading of 876 ton/yr), TN 1,985 ton/yr(96% of the total TN loading of 2,062 ton/yr) and TP 37.1 ton/yr(92% of the total TP loading of 40.3 ton/yr) in the year 2003.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2019.05a
• /
• pp.290-290
• /
• 2019

최근 우리나라 수자원 오염의 심각성에 관한 인식이 커지고 있으며, 수질 및 조류 관리의 필요성이 다양한 분야에서 증가하고 있다. 우리나라의 경우 초여름부터 장마 이전과 장마 이후부터 10월까지 호소의 영양 단계가 조류의 성장에 충분한 상태이기 때문에 남조류가 대량으로 증식된다. 하지만 기상 조건에 따라 조류의 발생 시기와 발생 정도는 매년 다르게 나타날 수 있다. 한편, 조류를 포함한 수질 모의 모형은 현재의 상태에 대한 정확한 모사를 통해 수질 관리와 미래의 예측 등 다양한 방면으로 활용된다. 따라서 복잡한 현상을 모형을 통해 재현하는 것은 중요하다. 본 연구에서는 대청호 지역을 대상으로 CE-QUAL-W2 모형을 이용하여 2016년 1월부터 2018년 7월까지 수질 및 조류의 거동을 모의하였다. 금강의 지류 하천인 소옥천에 위치한 옥천천 측정소부터 대청호 내부의 대청댐5 구간을 상류 및 하류 경계로 설정하였고, 수질 및 조류의 모의를 위해 물환경 정보시스템과 실시간 수질 정보시스템의 관측자료 및 대청댐의 운영 자료, 기상청의 기상관측 자료를 수집하였다. 모형의 안정화(warm up) 기간을 고려하여 2015년 1월부터 2018년 7월까지 주요 수질 항목인 수온, 용존산소, 총 인, 총 질소, 클로로필-a에 대한 분석을 수행하였고, 연구대상 지역 내의 대청댐6 지점의 관측값과 모의 결과를 비교 분석하였다. 수온과 용존산소, 클로로필-a의 경우 모의 결과가 관측 값을 비교적 잘 모사하였지만, 총 인과 총 질소의 경우 자동 수질 측정지점의 값과 일반수질 측정 지점의 측정 방법의 차이로 인해 오차가 다소 발생하는 것을 확인할 수 있었다. 본 연구는 CE-QUAL-W2 모형을 이용한 수질 및 조류 모의에 관한 연구로서, CE-QUAL-W2 모형을 이용한 수질 및 조류 관리에 활용될 수 있을 것으로 판단된다.

• Journal of Korean Society of Environmental Engineers
• /
• v.37 no.5
• /
• pp.277-284
• /
• 2015

In order to analyze the contamination level of sediment samples taken from Chusori and Chudong areas in Daechung Reservoir, the particle size and concentrations of organics and nutrients were analyzed and phosphorus fractionation analysis was conducted. The average fraction of silt-sized particles was 92% in the sediments taken from Chudong area and Chusori area at the site adjacent to main current, which was higher than that from the upper Chusori area. The concentrations of total phosphorus in the sediments at Chusori and Chudong area were 999 (${\pm}98$) and 1,123 (${\pm}119$) mg/kg sediment, respectively. The fractions of autochthonous phosphorus, which can be readily eluted by change of environmental conditions, were much higher than those of allochthonous phosphorus, indicating the internal load can contribute the eutrophication in these areas. The concentrations of total nitrogen were over 5,600 mg/kg sediment in all samples, which is the guideline of Contamination Assessment of River and Lake Sediments of the Ministry of Environment, indicating the contamination level of total nitrogen is serious in the sediments. It is concluded that the countermeasures to manage the quality of sediments are required to improve the water quality in the Daechung Reservoir.

• Spatial Information Research
• /
• v.20 no.5
• /
• pp.25-35
• /
• 2012

This study compared the influence of water quality according to the data sources of spatial information. Firstly, land cover map was constructed through image classification of Daecheong-dam basin and the accuracy of image classification from satellite image showed high as 88.76% in comparison with the large-scaled land cover map in Ministry of Environment, to calculate Event Mean Concentration (EMC) by land cover that impact on the evaluation of nonpoint source pollutant loads. Also curve number and direct runoff were calculated by spatial overlay with soil map and land cover map from image classification. And Seokcheon and Daecheong-Dam basin showed high in the analysis of curve number and direct runoff. Samgacheon-Joint and Sokcheon-Downstream basin showed high in the nonpoint source pollutant loads of BOD from direct runoff and EMC. And Samgacheon-Joint and Bonghwangcheon- Downstream basin showed high in the nonpoint source pollutant loads of TN and TP. Nonpoint source pollutant loads from image classification were compared with those by the land cover map from Ministry of Environment to present the effectivity of nonpoint source pollutant loads from satellite image. And Daecheong-Dam Upstream basin showed high as 10.64%, 11.70% and 20.00% respectively in the errors of nonpoint source pollutant loads of BOD, TN, and TP. Therefore, it is desirable that spatial information including with paddy and dry field is applied to the evaluation of nonpoint source pollutant loads in order to simulate water quality of basin effectively.

• Korean Journal of Microbiology
• /
• v.45 no.4
• /
• pp.362-367
• /
• 2009

Among total 176 strains with antialgal effects isolated from So-ok stream in Korea, Pseudomonas aeruginosa AJ1 showed the highest removal efficiency for an algal species Microcystis aeruginosa (clear zone of diameter 50.0 mm on algal lawn after 20 days). The algal growth was suppressed even when the supernatant of AJ1 culture was applied, suggesting that extracellular substances are responsible for its antialgal activity. The removal activity of AJ1 was optimal under the following condition: pH 8, $30^{\circ}C$, and mannitol as a carbon source. The antialgal activity of AJ1 appeared to be dependent of the growth phase of M. aeruginosa, i.e., the highest at the early phase, but not its own phase. As expected, the algicidal effect was improved as the amount of the treated supernatant was increased; the highest removal efficiency (80.3%) was achieved when 40 ml/L of the supernatant was used. Interestingly, however, the removal rate was opposite. The highest removal rate ($8.2{\mu}g$ chl-a/ml supernatant/day) was achieved when low concentration (10 ml/L) was applied. These results suggest that P. aeruginosa AJ1 is a promising biological agent to control the problematic algal bloom.

• Korean Journal of Ecology and Environment
• /
• v.49 no.3
• /
• pp.153-175
• /
• 2016

Daecheong Reservoir has suffered eutrophication and water-blooms by blue-green algae from initial impoundment, and algae alert system (AAS) was introduced in 1997. The purpose of this study was to investigate the effect of rainfall and hydrological factors in increase or decrease variability of green-tide and prolonged AAS, studied and analyzed the current situation of AAS has been operating for 19 years (1997~2015) in Daecheong Reservoir. The total issued number of AAS was 46 times, the most frequent period in August and September were 22 times (752 days) and 16 times (431 days), respectively, it accounted for 82.6%. Many number and frequency during this period were significantly associated with rainfall, various discharge and water level. Rainfall and hydrological events are associated with the rainy season of monsoon-Changma and the typhoon, it was concentrated in June~September, total rainfall in this period accounted for 69.9% of the annual rainfall. An increase in inflows was dependent on the intensity, frequency and the amount of rainfall. Accounted for 68.4% of the total annual inflow, it was a time when the most rapidly changing hydrological variability in the reservoir. The total outflow was closely related to rainfall, and compared the distinctive characteristics of hydropower generation and watergate-spillway discharge. In addition, the upreservoir zone of Daecheong Reservoir could be vulnerable to green-tide by regulating discharge of the upstream dam. The issue of AAS was strongly related to the with and without of watergate-spillway discharge. The watergate-spillway discharge had a total of 25 times, it was maximum 17 days from July to September in the year. And the opening times and each duration of the watergate were 1~4 times and the range of 3~37 days, respectively. When the watergate opened, the issue of AAS was maintained to 13 years and the movement of water bodies and green-tide was great about five times than that of non-open, had a profound effect on prolonged AAS within reservoir. In Daecheong Reservoir, Chusori (CHU) area of the So-ok Stream was still showing serious symptoms green-tide levels in the summer, but Janggye (JAN) waters of the main reservoir was pointed out that more important. AAS will be operated by an absolutely consider the rainfall and hydrological effects around the watergate-spillway discharge. The measures of green-tide will be included in the limnological studies more suited to the characteristics of the watershed and reservoir of the our country. Finally, from now on, we will prepare the systematic management and guidelines for vulnerable zone water-blooms that are the source within the reservoir before the monsoon rather than waiting for the arrival of green-tide on the operating stations of AAS.