• 환경영향평가
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• 제16권5호
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• pp.341-350
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• 2007

Lake Youngrang is a lagoon whose effluent flows into the East Sea. Because two resort towns and two golf courses are situated at the lake basin, many tourists visit this area. Stormwater runoff surveys were carried out for the eight storm events from 2004 to 2005 in the eutrophic lake watershed to give a basic data for the diffuse pollution control of the lake. Dimensionless mass-volume curves indicating the distribution of pollutant mass vs. volume were used to analyze the first flush phenomenon. The mass-volume curves were fitted with a power function and polynomial equation curves. The regression analysis showed that the polynomial equation curves were better than the power function in representing the tendency of the first flush, and second degree polynomial equation curves indicated the strength of the first flush effectively.

• 한국농공학회지
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• 제44권6호
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• pp.124-136
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• 2002

A freshwater lake water quality management system(FLAQUM) was developed to help regional manager for the water quality of a rural basin. The integrated user interface system FLAQUM written in Visual Basic, includes three subsystems such as a database management system, basin pollutant loads simulation model using SWMM model and freshwater lake water quality simulation model using WASP5 model. Pollutant load simulation model was applied to simulate the discharge and pollutant loading from the watershed, and freshwater lake water quality model was applied to analyze the changes in water quality with respect to watershed pollutant loads, and this model could be used in planning to control watershed pollutant source for water quality management. Database management system was constructed fur all input and output data processing, and it can be used to analyze statistical characteristics using constructed data. Results are displayed both graph and text for convenience of user. The results of FLAQUM application to Boryeong freshwater lake showed that the lake was in eutrophic condition. The major contribution of pollution comes from tributary No.1 and No.4, which have a large number of livestock farms. Therefore, water quality management must be focused on appropriate management of the livestock farming in the two breanchs.

• 환경영향평가
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• 제18권2호
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• pp.59-67
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• 2009

Water quality of the Lake Youngrang in the Sokcho City is eutrophic. Jangcheon is the largest inflow source to the lake. Major pollutant sources are stormwater runoff from resort areas and various land uses in the Jangcheon watershed. A storm sewer on the southern end of the lake is also an important pollution source. In this study, water quality modelling for Lake Youngrang was carried out considering the rainfall-runoff pollution loads from the watershed. The rainfall-runoff curves and the rainfall-runoff pollutant load curves were derived from the rainfall-runoff survey data during the recent 4 years. The rainfall-runoff pollution loads and flow from the Jangcheon watershed and the storm sewer were estimated using the two kinds of curves, and they were used as the flow and the boundary data of the WASP model. With the measured water quality data of the year 2005 and 2006, WASP model was calibrated. Non-point pollution control measures such as wet pond and infiltration trench were considered as the alternative for water quality management of the lake. The predicted water quality were compared with those under the present condition, and the improvement effect of the lake water quality were analyzed.

• 한국환경보건학회지
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• 제35권5호
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• pp.376-385
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• 2009

The characteristics of Lake Cheonhoji water and sediment were investigated in oder to utilize these as fundamental materials for the management of lake water quality. The hydrographic properties of Lake Cheonhoji which are relatively low chance of nutrients loading from the watershed and a long retention time of lake water, lead to the probability of high lake productivity. It was also observed that lake water showed stratification during summer and complete mixing during fall, even though water depth was relatively shallow. The trophic state was eutrophic to hypertrophic from summer to late fall. The overall properties of the sediment were oligohumic, high ignition loss and high composition of NAIP and Resid.-P, which might serve as potential pollution sources of lake water quality. In laboratory scale experiments, it was observed that leaching potential of nutrients in the sediment was greatly dependant upon water temperature and dissolved oxygen. Finally, water pollution in Lake Cheonhoji was considered to be largely due to the adverse cycle of uncontrollable eutrophication, which resulted in the subsequent occurrence of dead algae and animal plankton, organic sedimentation, reduction of dissolved oxygen and nutrients leaching, which again reinforced the cycle of eutrophication in the lake.

• 한국물환경학회지
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• 제21권4호
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• pp.360-367
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• 2005

We have performed to analyze the trophic state resulting of Lake Yongdam as a result of water quality and nutrient concentration. Lake Yongdam is artifitial multi-purpose Dam resulting from the floods of 2001. The water quality of Lake Yongdam may affect the status of the Geum river basin including the Daecheong reservoir. It is necessary to understand the trophic state to assess water quality until stability after flooding. Water quality was surveyed using depth and hydraulic condition analysis. Further density flow was estimated for stratification and trophic state of Lake Yongdam by chlorophyll ${\alpha}$ concentration (2001~2004). And Environmental factors on chlorophyll ${\alpha}$ concentration were analyzed statistically. Trophic state was evaluated as the oligotrophic state at the main stream of the reservoir and eutrophic state at the upper stream in 2001, but evaluated as eutrophic state in 2002 and 2003 by TSI of Aizaki. From the results of multiple regression analysis using stepwise method, chlorophyll ${\alpha}$ concentration was shown to be very significant when nutrient concentration is high upon initial filling of the Dam. Chlorophyll ${\alpha}$ concentration varied according to sample site, season and year. Concentration were high in the upper stream of Lake Yongdam 4, algae bloom in these watershed were affected by location and high nutrient levels in the summer season which have in turn increased phytoplankton bloom into the reservoir.

• 한국물환경학회지
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• 제25권3호
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• pp.386-393
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• 2009

This study was carried out to assess water quality and to introduce the management measures for water quality improvement with the collected data from 87 agricultural reservoirs in Han river watershed. According to the water quality criteria (WQC) for lake based on the COD, TP, TN and chl.a concentration, 18, 16, 4 and 19 of 87 reservoirs exceed class IV, respectively. Based on the trophic state index (TSI) with chl.a concentration, 51 of selected reservoirs appeared to be eutrophic. Phosphorus was limiting nutrient on algal growth in 58 reservoirs. TP, chl.a and COD concentration in 23 of 49 agricultural reservoirs with chl.a concentration ${\geq}25{\mu}g/L$ and eutrophic exceed class IV by WQC. Also, the mean depth in 21 of 23 reservoirs was below 5m. Our results suggest that advanced wastewater treatment and crop land control in watershed of reservoirs with TP concentration ${\geq}0.1mg/L$ would be a effective tool to improve water quality. Dredging would to be effective measure in reservoirs with mean depth < 5 m and relatively old age. In reservoirs with chl.a concentration ${\geq}50{\mu}g/L$, application of technique such dissolved air flotation (DAF) and P inactivation be effective to improve water quality by removing particulate matters in water column. The management measure to control inflow such as sedimentation basin, Pre-dam and diversion would to be application in reservoirs with shallow depth, while large watershed and surface area.

• Journal of Ecology and Environment
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• 제36권3호
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• pp.183-191
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• 2013

Dissolved organic carbon (DOC) concentrations and zooplankton and particulate organic matter (POM) ${\delta}^{13}C$ values were measured in five reservoirs in Korea. Zooplankton ${\delta}^{13}C$ and POM ${\delta}^{13}C$ showed large range from -33‰ to -22‰ and a significant difference among the reservoirs. One eutrophic reservoir, Lake Masan, showed unique characteristics with the highest zooplankton density, the highest ${\delta}^{13}C$, and the highest DOC. Zooplankton ${\delta}^{13}C$ was similar to POM ${\delta}^{13}C$, implying that zooplankton occupies substantial portion of POM or that zooplankton isotopic composition is related to selective grazing and assimilation of food sources from bulk POM. Except Lake Masan zooplankton ${\delta}^{13}C$ values were negatively correlated to DOC concentration in four reservoirs with mostly forest land use. This pattern can be probably attributed to intensive agricultural land use in the watershed of Lake Masan compared to the mostly forest land use in the other watersheds. Understanding the relationship between zooplankton ${\delta}^{13}C$ values and the origin of organic matter associated with watershed characteristics will be valuable to better understand trophic relationships in reservoirs in the summer monsoon region.

• 환경영향평가
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• 제15권6호
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• pp.435-441
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• 2006

For the calibration of rainfall-runoff model, automatic calibration methods are used instead of manual calibration to obtain the reliable modeling results. When mathematical programming techniques such as linear programming and nonlinear programming are applied, there is a possibility to arrive at the local optimum. To solve this problem, genetic algorithm is introduced in this study. It is very simple and easy to understand but also applicable to any complicated mathematical problem, and it can find out the global optimum solution effectively. The objective of this study is to develope a parameter optimization program that integrate a genetic algorithm and a rainfall-runoff model. The program can calibrate the various parameters related to the runoff process automatically. As a rainfall-runoff model, SWMM is applied. The automatic calibration program developed in this study is applied to the Jangcheon watershed flowing into the Youngrang Lake that is in the eutrophic state. Runoff surveys were carried out for two storm events on the Jangcheon watershed. The peak flow and runoff volume estimated by the calibrated model with the survey data shows good agreement with the observed values.

• 생태와환경
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• 제36권3호통권104호
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• pp.381-388
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• 2003

The fertility of stream water in major streams of the Lake Shihwa Watershed was compared using water analyses and algal growth potential test (AGPT) in typical drought seasons from December 2001 to April 2002, The water quality varied considerably depending on streams. These streams were very rich in inorganic nutrients that the nutrient levels and characteristics of each stream could be easily determined. Through AGPT, 63.6% of growth was observed in the average values of each stream, with non-growth accounting for 36.4%. AGPT results showed that 40.9% of the 22 stations were in hypertrophic condition and 54.5% in eutrophic condition. AGPT values were significantly correlated with TIN, $NH_4$, and SRP (p <0.001); compared to other nutrients, however, they were more related to SRP and $NH_4$. Moreover, the values increased with high concentration of N and P and low N/P ratios. Nonetheless, the values were more dependent on P concentration than N concentration. This suggests that the effect of P on the water quality of lake situated in downstream may serve as a potential indicator of phytoplankton development. Depending on the drainage pattern of streams, the wastewaters of wastewater treatment plant (WwTP) and untreated wastewater (UTW) were found to have 53.4% and 46.6%, respevtively, of TIN, 51.9% and 48.1% of $NH_4$, 62.9% and 37.1% of $NO_3$, 62.6% and 37.4% of SRP, and 44.1% and 55.9% of SRSi. The AGPT value was 51.1% in WwTP wastewater and 48.9% in UTW wastewater, the concentration of WwTP wastewater was slightly higher. For untreated wastewaters flowing into the constructed wetland and into the lake, TIN accounts for 43.0% and 57.0%, respectively, of nitrogen components, $NH_4$ 44.4% and 55.6%, $NO_3$ 39.6% and 60.4%, SRP 53.5% and 46.5%, and SRSi 52.3% and 47.7%, respectively. The AGPT value was 58.0% in the constructed wetland and 42.0% in Lake Shihwa; the concentration in streams flowing into the wetland was slightly higher. Therefore, Persistent and large development of phytoplankton in Lake Shihwa cannot be prevented unless a measure tophytoplankton control is implemented. This is because the concentration of nutrients in specific streams flowing into the lake is very high, even though the inflow of water is low.

• 한국수자원학회논문집
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• 제34권5호
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• pp.487-497
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• 2001

옥정호에 대한 수질변화 조사 자료를 토대로 수질모의를 실시하였으며, 그 결과 바탕으로 효율적인 댐저수지 수질관리 방안을 제시하였다. 옥정호의 수질은 계절에 다라 중영양상태와 부영양상태를 나타내는 것으로 평가되었으며 이러한 수질상태는 외부로부터 유입되는 오염원에 많은 영향을 받게 되므로 우선 유역으로부터 유입되는 오염부하의 정확한 산정이 필요한 것으로 평가되었다. 1999년에 조사한 7차례의 강우기간 중 총 부하와 일년간 발생한 총 부하를 비교하면 강우량은 17.5%인데 비해 SS는 72.8%, TN과 TP는 약 50%가 강우기에 유입되는 것으로 조상되었다. 또한 퇴적물의 용출율은 TP의 경우 가두리 양식장이 운영되던 지점에서는 11.92 mg/L, 정기수질 조사지점에서 0.2∼1.9 mg/L로 국내·외 자료와 비교하여 용출율이 작은 것으로 나타났다. 댐저수지 수질관리 방안 수립을 위하여 WASP5 모형을 적용하였으며 검증된 결과를 이용하여 각 소유역에서 오염부하 삭감에 따른 6가지 방안에 대한 수질모의를 실시하였고 각각에 대한 수질개선 효과를 제시하였다. 가장 효율적인 방안은 임실천 유역과 관촌교 유역의 오염부하를 제어하는 방안으로 평가되었으며, 가장 수질개선효과가 좋은 것은 대표 세유역의 오염부하를 제어하는 것으로 나타났다. 이를 바탕으로 수질개선을 위한 하·폐수처리장의 건설 적지를 제시하였다.