• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.16 no.2
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• pp.225-233
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• 1998

It is necessary to check the water quality of the lake on a continuous basis to determine the appearance of water pollution; however, it not only takes much time and expenses but it is considerably difficult to investigate the wide range of the area. If we use the remote sensing technique through the use of satellites, the status of water quality can be checked covering many wide areas simultaneously; and because the same area can be measured on a periodic basis, it is extremely effective in investigating the water quality. Furthermore, as some of the Landsat sensors carry characteristics which sense objects according to wave length, the distribution of water quality can be checked relatively accurately within a short period of time, while its image can be displayed in color. Hence, this research has attempted to extract water quality elements, such as transparency, water depth, and surface water temperature by utilizing the satellite data, and has prepared the water quality distribution image map of the Lake Hwajinpo by presenting the related empirical formula of the water quality elements. If the water quality distribution image map is prepared after extracting the water quality elements from the DN of the Landsat TM image and then carrying out TIN analysis through the use of GIS, relatively more accurate pattern can be learned covering a wide rage of area than the pattern presented based on the value obtained from actual observation.

• Analytical Science and Technology
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• v.14 no.3
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• pp.238-243
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• 2001

The study was carried out to analysis of the pollutant $COD_{Mn}$, T-N, T-P for water quality proximated to sediment in lake of K river basin. water extracted from sediment showed higher $COD_{Mn}$, T-N, T-P datas than water proximated to sediment. Also, water proximated to sediment and water 5-10cm proximated to sediment showed the following data : $COD_{Mn}$, 1.2~1.9mg/L, T-N, 1.3~6.2mg/L, TP, 0.05~0.26mg/L, respectively. From this results, we have known the fact that the pollution degree of sediment have an effect on the water quality in lake and stream.

• Journal of Korean Society on Water Environment
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• v.28 no.6
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• pp.866-881
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• 2012

Han River is a complex water system consisting of many lakes. The water quality of Lake Paldang is significantly affected by incoming flows, which are the South and North branches of the Han River, and the Kyungan Stream. In order to manage the water quality of the Lake Paldang, we should consider the entire water body where the incoming flows are included. The objectives of this study are to develop an integrated river and lake modeling system for Han River system using a multidimensional dynamic model and evaluate the model's performance against field measurement data. The integrated model was calibrated and verified using field measurement data obtained in 2007 and 2008. The model showed satisfactory performance in predicting temporal variations of water level, flow rate and temperature. The Root Mean Square Error (RMSE) for water temperature simulation were $0.88{\sim}2.13^{\circ}C$ (calibration period) and $1.05{\sim}2.00^{\circ}C$ (verification period) respectively. And Nash-Sutcliffe Efficiency (NSE) for water temperature simulation were 1089~0.98 (calibration period) and 0.90~0.98 (verification period). Utilizing the validated model, we analyzed the spatial and temporal distributions of temperature within Han River system. The variations of temperature along the river reaches and vertical thermal profiles for each lakes were effectively simulated with developed model. The suggested modeling system can be effectively used for integrated water quality management of water system consisting of many rivers and lakes.

• KCID journal
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• v.19 no.1
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• pp.19-29
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• 2012

The data of the agricultural water quality survey network was analyzed between from 1990 to 2010 in order to propose effective plans for water quality management by analyzing the characteristics of agricultural lakes and the change of water quality. The result of the analysis shows that there is a correlation between water quality and items that can be a function of water depth such as dam height, dam length, dam height/dam length ratio and active storage/surface area of lake ratio. This means that, Korean agricultural lakes, there is a correlation between water quality and water depth. Water quality of the lakes that have lower than 5m of active storage/surface area of lake ratio (effective water depth) especially tends to get worse rapidly. The Chl-a and COD concentration of Korean agricultural lakes have a tendency to increase between June and September. Therefore, we recommend first taking a water quality improvement project for the lakes preformed watershed management project, and taking a preventive short-term water quality improvement project for the unperformed lakes before June among lakes that have lower than 5m of effective water depth.

• Korean Journal of Ecology and Environment
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• v.37 no.4 s.109
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• pp.448-454
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• 2004

In order to evaluate the water quality (N, P and C) and the biological mass balance of semi-enclosed brackish Lake Obuchi, Japan, an ecosystem model was developed and applied to the lake, using the flow field calculated by a hydrodynamic model. The time series data of the observed tide level, river discharge and meteorological parameters from January 2001 to December 2002 were incorporated as the parameters of the hydrodynamic model. Water quality and biomass balance were estimated by the ecosystem model, and simulated fluctuations In water quality agreed with our observations. The carbon contents of POC, phytoplankton and zooplankton in the lake were calculated by the model at an average 7200, 1500 and 22 kg, respectively, which somewhat agreed with our observations of POC (5900 kg), phytoplankton (3800kg), and zooplankton (150kg).

• Journal of Marine Bioscience and Biotechnology
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• v.10 no.2
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• pp.91-96
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• 2018

There are many eutrophic lakes by point and non-point pollution sources such as in dustrial waste water, domestic raw sewage, and mucks. The eutrophic lakes not only cause algal blooms but also destroy the ecosystem in the lakes due to high nutrient concentrations. The purpose of this study was to improve water quality in eutrophic lakes by cultivating microalgae using photobioreactors (PBRs) with selectively permeable mesh (SPM), supplying nutrients in the lake and inhibiting cell leakage by diffusion and water permeability. Chlorella vulgaris, was cultivated using PBRs with SPM installed in Inkyung Lake located in Inha university, Incheon, Korea. When cultivating C. vulgaris, $8.3g/m^2/day$ of average biomass productivity was obtained at 3 days. Furthermore, concentrations of total nitrogen and phosphorus were reduced by 35.7% and 84.2%, respectively, compared to initial condition and water quality in eutrophic lake was improved to oligotrophic environment. These results suggest that microalgal cultivation using PBRs with SPM in the lake could produce microalgal biomass as well as improve water quality by decreasing nutrient concentrations.

• Magazine of the Korean Society of Agricultural Engineers
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• v.43 no.6
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• pp.174-186
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• 2001

Excessive outflow of pollutant loads resulting from rapid industrialization has unbalanced the water ecosystem, deteriorating the water quality environment severely. Therefore, measures for improving the water quality are necessary to maintain clean reservoir water and restore water-friendly spaces. A water quality model which is capable of simulating daily reservoir water quality was developed. The model had been applied to Masan reservoir and Wanggung reservoir in Korea. The model appeared to be satisfactory in representing the trend of water quality variations by comparing measured and simulated results. The model had been also applied to assess water purification techniques such as dredged pool, floating island and vegetation purification system. The model was considered to assess the effect of water purification techniques on reservoir water quality improvement. The results of water quality simulation for lake water purification techniques showed that a large facility would be needed to meet the targeted water quality of the reservoir when only one technique is applied. To effectively improve the quality of the polluted reservoir water, it is therefore recommended that pollutant sources should first be controlled, and a combination of the water purification techniques applied to make the utmost use of their secondary effects such as conservation of the reservoir volume capacity, establishment of a recreation space, promotion of bio-diversity, and improvement of the lake landscape.

• Water for future
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• v.29 no.5
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• pp.51-56
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• 1996

• Journal of Environmental Impact Assessment
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• v.8 no.1
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• pp.81-92
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• 1999

This study discussed the appropriateness of organic matter indexes such as biochemical oxygen demand(BOD) and chemical oxygen demand with potassium permanganate($COD_{Mn}$) in water quality environmental standard of streams and lakes and the applicability of the items to water quality environmental standard to add or substitute COD with potassium dichromate ($COD_{Cr}$) and total organic carbon(TOC) being used as index of organic matter. And indexes of organic matter content and organic carbon concentration were distinguished between dissolved and particulate component in water sample to estimate their effect on pollutants loading in lake and stream. The ratio of $COD_{Cr}$/BOD was 5.1 under BOD concentration 3mg/L in river water quality environmental standard II, and 2.67 above it. This ratio was diminished to 2.04 when BOD concentration was more than 8mg/L, in river quality environmental standard IV. Also the ratio of $COD_{Mn}$/BOD showed 2.16 under 3mg/L(BOD), and 1.1 above it. This ratio is also diminished to 0.84 over 8mg/L(BOD). Accordingly, we should apply this ratio depending on the concentration level to add and change organic matter index of water quality environmental standard newly. The ratio $COD_{Cr}/COD_{Mn}$ both in lake and stream shows 2.37(r=0.986, p<0.001). But the ratios showed range of 2.34~2.50, which is no much difference of this ratio according to $COD_{Mn}$ concentration.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2002.10a
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• pp.365-368
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• 2002

In spite of considerable advances in water quality control measures within lake, many basic questions concerning an eutrophication still remains unanswered and it becomes obvious that an extensive limnological database is needed for the inter-comparison between bodies of water and for the assessment of the status of lake water quality. In order to diagnose the water environment and assess the changes of the water quality, Wangkung irrigation reservoir was investigated by a long-term monitoring program for the physical, chemical and biological water quality parameters. In addition, these data was used to determine the design elements of natural purification facilities.