• Journal of Environmental Impact Assessment
• /
• v.9 no.2
• /
• pp.99-107
• /
• 2000

In order to solve water quality problem of domestic dam reservoir, many projects have been performed in a point of view to restoration of water quality. This study was carried out to evaluate the effect of release from sediment on water quality and release characteristics. Daecheong dam reservoir was investigated for two years, from 1998 to 1999. The nutrient release rates of Daecheong reservoir is less than foreign eutrophic reservoir at anoxic condition. For the evaluation of the effect of nutrient release on water quality, internal and external loading was calculated at Daecheong reservoir. As total phosphorus loading from sediment is calculated 9.3 ton/yr and inflow loading from Daecheong reservoir watershed 118 ton/yr, internal loading shows the portion of 7.88% to external loading. At this study, because sampling point was choosed at the point where much sediment is accumulated, experimental result is more than average release rates. Because Daecheong reservoir shows complete thermal stratification and anoxic condition below 30m from water surface in summer seasons, released phosphorus from sediment can not transfer to epilimnion and eventually resettles. Therefore sediment has insignificant impacts on water quality on Daecheong dam reservoir.

• Journal of Environmental Impact Assessment
• /
• v.21 no.3
• /
• pp.367-380
• /
• 2012

There are many long and round shape shores due to terrain characteristics in Daecheong reservoir. Therefore it is indicated different spatial distribution of algae every year since the stream is being regulated by these terrain characteristics and reservoir operation about inflow and outflow discharge. Also oversupply of nutrient salt from tributaries of Daecheong reservoir where pollutants were concentrated generates massive growth of algae and depending on hydrological, reservoir operation condition, those proliferated algae at the stagnant tributaries moves to the mainstream of Daecheong reservoir which could create problems of water quality. In this study, it was analyzed the tendency of algae generation by examining algae occurring status for the last 4 years since 2008, and implemented hydraulic analysis at Daecheong reservoir through numerical tracer simulation by applying 3-dimensional hydrodynamic model, ELCOM. Also it was implemented a quantitative analysis of causal relationship based on the algae generation tendency and hydraulic behavior at Daecheong reservoir. Through numerical tracer simulation in this study, it could be noticed the degree of spread of inflow indicated similar trend to the algae occurring status at Daecheong reservoir and verified the different tendency of algae generation in 2011 unlike previous year caused by the rise of water temperature.

• Journal of Korean Society on Water Environment
• /
• v.22 no.5
• /
• pp.887-894
• /
• 2006

Water quality in the Daecheong reservoir has been deteriorated by algal bloom every year. Algal bloom is propagated from eutrophicated tributary into the main body of the reservoir during the wet season. Nutrients from diffuse sources trigger the propagation of the algal bloom. This study is aimed to analyze relationship between the water current by the simulation and algae transport from the main body in the Daecheong reservoir including tributary where algal bloom has occurred seriously every year. Water quality model CE-QUAL-W2 was applied to analyze water movement in draught season (2001) and flooding season (2003). The result of simulation corresponded with the observed water elevation level, 63~80 m and showed stratification of the Daecheong reservoir. In the draught season, as velocity and direction off low in the reservoir was estimated to affect algae transport including nutrient supply from small tributary, algal blooms occurred in the stagnate zone of middle stream of the reservoir. On the other hand, in the flooding season, it was resulted in nutrient transport from upstream of main reservoir and nutrients were delivered up to downstream by fast water velocity. In result, algal blooms occurred in stagnate zone of reservoir downstream as the current of downstream was retarded according to dam outflow control.

• Spatial Information Research
• /
• v.12 no.1
• /
• pp.13-27
• /
• 2004

The current industrial development and the increase of population in Daecheong Reservoir basin have produced a rapid increase of wastewater discharge. This has resulted in problem of water quality control and management. Although many efforts have been carried out, reservoir water quality has not significantly improved. In this sense, the development of water quality management system is required to improve reservoir water quality. The goal of this study is to design a GIS-based water quality management system for the scientific water quality control and management in the Daecheong Reservoir. For general water quality analysis, WASP5 model was applied to the Daecheong Reservoir. A sensitivity analysis was made to determine significant parameters and an optimization was made to estimate optimal values. The calibration and verification were performed by using observed water quality data for Daecheong Reservoir. A water quality management system for Daecheong Reservoir was made by connecting the WASP5 model to ArcView. It allows a Windows-based Graphic User Interface(GUI) to implement all operation with regard to water quality analysis. The proposed water quality management system has capability for the on-line data process including water quality simulation, and has a post processor far the reasonable visualization for various output. The modeling system in this study will be an efficient NGIS(National Geographic Information System) far planning of reservoir water quality management.

• Journal of Korean Society on Water Environment
• /
• v.24 no.5
• /
• pp.598-602
• /
• 2008

The Daecheong Reservoir is the largest multi-purpose reservoir in the Keum River basin. This water supply is subject to some of the most serious taste and odor (T&O) problems in the region. The intensity of T&O events increased due to eutrophication during the 1990s. In this study, the temporal occurrence of T&O in raw water from the main Daecheong Reservoir and its regulating reservoir was compared using both an instrumental method (CLSA+GC/MS) and threshold odor number (TON) test from April to December 2006. In addition, biofilms on the submerged macrophytes and rocks were analyzed for two typical T&O causing compounds, Geosmin and 2-MIB. The maximum concentration of Geosmin in the main reservoir was almost two times higher than that in the regulating reservoir. Interestingly, 2-MIB was only detected in water samples from the main reservoir. In the case of T&O causing compounds present in the biofilm on the submerged macrophytes and rocks, the regulating reservoir had lower concentrations compared to those of the main reservoir. It was found that both Geosmin and 2-MIB were detected from the biofilms much earlier than from the water samples. This result suggests that the occurrence of T&O compounds in the biofilms could be used as an early warning indicator of an imminent T&O outbreak in the water body.

• Korean Journal of Veterinary Service
• /
• v.15 no.2
• /
• pp.203-214
• /
• 1992

Livestock waste causes ground and surface water pollution, eutrophication of reservoir as well as adverse affects living environment of those who dwell nearby. In order to investigate the pollution load from livestock waste, physical and chemical characteristics of the waste were determinded in the survey of livestock farms. Once pollution load is obtained as a function of the origin units of livestock, the influence of livestock waste on the Daecheong reservoir was studied. 1. For Daecheong reservoir inflow area, the liverstock manure productions of beef cattle swine, dairy cattle and chicken were 1,135.6t/day, 480t/day, 241.3t/day, 48t/day respectively； Beef cattle was the mai or source of the pollution. Pollution loading productions due to the livestock waste around the were found to be 53.31t/day for BOD, 222.49t /day for COD, 261.99t/day for T-S, 9.64t/day for T-N, 6.54t/day for T-P 2. Bocheong stream turnd out to be the major contribution for pollution loading production to Daecheong reservoir with 10,748kg /day of BOD, 47,157kg /day of COD, 1,946kg /day of T-N, 1,271kg /day of T-p. 3. Actual pollution loadings from livestock wastes for the area of Daecheong reservoir were estimated as 1,997kg /day(BOD), 8,546kg /day(COD), 364kg /day(T-N), 243kg /day (T-P), respectively Therefore, advanced treatment for livestock waste is recommended for Daectleong reservoir inflow area to eliminate the nutrients which are major sources of eutrophication of the reservoir.

• Journal of Korean Society on Water Environment
• /
• v.23 no.1
• /
• pp.52-63
• /
• 2007

The objectives of this study were to setup a laterally-averaged two-dimensional eutrophication model in Daecheong Reservoir, and to validate the model under two different hydrological conditions; drought year (2001) and wet year (2004). The suggested modeling approach was found to be very effective to simulate the dynamic variations of water temperature, nutrients, dissolved oxygen, and algae in the reservoir. The model satisfactorily replicated the algal bloom that happened between Janggae (Sta.4) and Haenam (Sta.5) during summer of 2001, although the peak concentration was slightly underestimated due to the laterally averaged assumption. The allochthonous phosphorus and algae induced from upstream and So-oak stream during several rainfall events were found to be most significant sources of algal bloom in 2001. In contrast to draught year, the flood events happened during summer months of 2004 tended to remove the hypolimnetic anaerobic conditions and dilute the dissolved phosphorus in the upper reach of the reservoir, and in turn mitigated algal bloom. It implies that the impact of hydrological and hydrodynamic conditions on the reservoir water quality is highly significant, and a drought year may be more vulnerable to algal bloom in the reservoir.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.10 no.2
• /
• pp.91-102
• /
• 2007

To anticipate and respond to harmful algae produced in a big artificial lake like Daecheong reservoir, development of a regional analysis computer system using GIS or RS technique is needed in addition to biological and chemical research. The purpose of this study is to develop a cyanobacterial blooming prediction model to prevent harmful algae produced in Daecheong reservoir and construct an early forecasting system based on GIS. For this purpose this paper examines previous studies related to the relationship between cyanobacteria and environmental factors in Daecheong reservoir and selects precipitation and air temperature as two important environmental factors for the development of cyanobacterial blooming prediction model. Data used in this study are water quality and weather data for three water regions in Daecheong reservoir between 2000 and 2004. Based on qualitative correlation analysis between cyanobacteria and environmental factors, this paper presents a Rump model which enables us to predict cyanobacteria in water regions of Daecheong reservoir. Under this model the prediction of initial occurrence time and growth period of cyanobacteria are possible. The model is also applied to the GIS-based early forecasting system for cyanobacteria, and finally a GIS which can predict cyanobacteria produced in Daecheong reservoir and can manage the related data is developed.

• Journal of Korean Society on Water Environment
• /
• v.25 no.6
• /
• pp.984-993
• /
• 2009

There have been growing concerns of algal growth at Daecheong reservoir due to eutrophication with excess nutrient inflow. Rainfall-driven runoff and pollutant from watershed are responsible for eutrophication of the Daecheong reservoir. In this study, two subwatersheds of the Daecheong reservoir were selected and water quality characteristics were analyzed. The L-THIA ArcView GIS model was used for evaluation of direct runoff and water quality. The $R^2$ and the EI value for direct runoff were 0.95 and 0.93 at Wol-oe watershed and were 0.81, 0.71 at An-nae watershed, respectively. The $R^2$ for SS, T-P were 0.53, 0.95 at Wol-oe watershed and 0.89, 0.89 at An-nae watershed, respectively. It has been proven that the L-THIA ArcView GIS model could be used for evaluating direct runoff and pollutant load from the watershed with reasonable accuracies.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.58 no.2
• /
• pp.53-63
• /
• 2016

Monitoring of cyanobacteria bloom in reservoir systems is important for water managers responsible of water supply system. Cyanobacteria affect the taste and smell of water and pose considerable filtration problems at water use places. Harmful cyanobacteria bloom in reservoir have significant economic impacts. We develop a new method for estimating the cyanobacteria bloom using Landsat TM and ETM+ data. Developed model was calibrated and cross-validated with existing in situ measurements from Daecheong Reservoir's Water Quality Monitoring Program and Algae Alarm System. Measurements data of three stations taken from 2004 to 2012 were matched with radiometrically converted reflectance data from the Landsat TM and ETM+ sensor. Stepwise multiple linear regression was used to select wavelengths in the Landsat TM and ETM+ bands 1, 2 and 4 that were most significant for predicting cyanobacteria cell number and bio-volume. Based on statistical analysis, the linear models were that included visible band ratios slightly outperformed single band models. The final monitoring models captured the extents of cyanobacteria blooms throughout the 2004-2012 study period. The results serve as an added broad area monitoring tool for water resource managers and present new insight into the initiation and propagation of cyanobacteria blooms in Daecheong reservoir.