• International Journal of Contents
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• v.18 no.1
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• pp.76-84
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• 2022

Tidal power generation plays a critical role in reducing greenhouse gas emissions. It uses a tidal force generated by gravitational force between the moon, the earth, and the sun. The change of seawater height generates the tide-generating force, and the magnitude of the change is the tide level. The tide level change has the same period as the tide-generating force twice a day, every 29.5 days, every year, and every 18.6 years. Sihwa Lake Tidal Power Station is Korea's first tidal power plant that began commercial power generation in August 2011 and has been accumulating a large volume of data on electricity production, power generation sales, sluice displacement, and tide levels. The purpose of this paper was to analyze the impact of the inefficiency factors affecting production and the tidal level change on tidal power generation and their characteristics using Sihwa Lake Tidal Power's operational performance data. Throughout this paper we show that tidal power generating operation is accurately predicting the trends of magnitude of tidal force to be periodical for each day. determining the drop to initiate the water turbine generator factoring the constraints on the operation of Sihwa Lake, and reflecting the water discharge through the floodgate and water turbine during the standby mode in the power generation plan to be in the optimal condition until the initiation of the next power generation can maximize power generation.

• Korean Journal of Environmental Biology
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• v.19 no.2
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• pp.159-171
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• 2001

Community structure, horizontal distribution, density, and ratio between nematodes and benthic harpacticoid copepods of the meiobenthos within the sediments of inner Sihwa Lake were investigated in May 1999 and May 2000. A total of 11 and 8 classes of meiobenthic animals were identified in 1999 and 2000, respectively, which were much lower than other coastal areas. The dominant animals during both sampling periods was the nematodes, followed by sarco-mastigophorans, nauplius of crustaceans, benthic harpacticoid copepods and polychaetes. These five classes of animals comprised more than 90% of total abundance of neiobenthos presented in the samples. In 2000, a lot of polychaete larvae were identified. The most abundant animal were the size that fits in 0.063 mm sieve size. Lower density was observed upper inner part of the Sihwa Lake during both sampling periods, and higher density was observed around the Sihwa floodgates. The average density between those two numbers were observed in the samples collected in the middle of the lake. Lower nematodes to betnhic harpacticoides (N/C) ratio, a relative indicator of environmental pollution, was observed to be lower around the floodgate but higher ratios were observed in the upper inner Sihwa Lake. The present study indicated that inner upper part of the lake becomes unsuitable for the meiobenthos, and the most inner upper lake was considered to be polluted.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.143-145
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• 2021

The Sihwa River was first planned to be a fresh water lake, but it failed due to serious environment pollution. During times of destruction and regeneration, changes of ecosystem of Sihwa River was visible, especially the algal ecosystem. It's because many seasonal birds pass through the place. This paper analyzes the changes of algal ecosystem of Sihwa River based on eight ecosystem indices. Moreover, using gradient descent, COD is expressed has a function of three ecosystem indices selected from above which is newly defined as SEI, Sihwa Ecosystem Index. In conclusion, we can observe the current ecosystem more easily without its actual data, but only with informations of the ecosystem.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.29 no.5
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• pp.247-259
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• 2017

Numerical model with LPT (Lagrangian Particle Tracking) module was used to understand the variation of residence time in the outer sea of the Sihwa lake result operating from the Sihwa tidal power plant. Numerical model was composed in order to investigate the spatial distribution characteristics, the average residence time in each area was calculated by dividing the outer sea area of Sihwa lake into 4 areas. The average residence time of the areas appeared to be increase as it entered the areas located in the inner bay (13 days) from the area located in most outer sea (3 days) both before and during operation. Variation of average residence time by areas were increased in the area that was located in the most outer sea of during operation compared to before operation, and decreased in the other area. Artificial discharges from tidal power plant induces particle traps in the formation of vortex in the area located in the most outer seas, entrainment in the remaining areas, which affects variation in residence time. In other words, the jet flow generated during drainage and the change in the residence time due to the vortex and entrainment action indicate the increase horizontal mixing of water in the outer sea and in the inner bay.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2005.11a
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• pp.539-541
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• 2005

• Journal of Soil and Groundwater Environment
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• v.12 no.4
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• pp.16-24
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• 2007

An investigation on the polluted sediments in the Lake Sihwa and the benthos that inhabited on the sediments was conducted. Cost effective remediation alternatives were derived form the results of the investigation. The sediment samples taken from four sampling points out of thirteen showed relatively high heavy metal (particularly copper) concentrations which exceeded the Effects Range Low (ERL) of the National Oceanic and Atmospheric Administration, USA. The four sampling points were located in front of industrial complexes. Although the heavy metals appeared to have affected the growth of the benthos, the concentration of it did not exceed the criteria of dredging that were developed by Netherlands or the State of Washington, USA. However, contamination by organic matters and sulfur compounds was severe, which exceeded the criteria of dredging that were established in Japan. The sediments taken from the four sampling points which were contaminated with heavy metals showed higher organic matter content in general. The organic matters in the sediments depleted oxygen in summer, which appeared to be fatal to the benthos. A comprehensive analysis on the sediments, benthos, and other environmental impact from the contaminated sediments drew a conclusion that the benthonic environment of the Lake Sihwa needed a stepwise remediation, giving a particular emphasis on the clean up of the sediments upstram of the Lake which could cause odor problems to the nearby residential area.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.333-338
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• 2016

The purpose of this study was to understand the pollution level of the surface sediment of Sihwa Lake by assessing its geochemical characteristics and investigating the spatial distribution of trace metals and organic matter. In the surface sediment of Sihwa lake, the mean grain size was between 2.94 and 6.35 Ø and the main type of sediment was sandy silt. The concentrations of As, Co, Cr, Ni, V and Li among the metal elements in the surface sediment were correlated with the mean crust concentration (p<0.05). Based on the strong correlation between the metals (Cd, Cu, Pb and Zn) and organic matter (Ignition Loss), the concentrations of these metal elements seem to be controlled by the organic matter dilution effect. The trace metal pollution level, determined by applying the Republic of Korea Marine environmental standard and the US National Oceanic and Atmospheric Administration's sediment quality guidelines, showed the pollution level of As to be either close to or in excess of the above-mentioned standards at almost all levels. The enrichment factor and geoaccumulation index of As showed that there was an incremental increase of pollution by elements other than V, Cr, Co, Fe, Al and Mn. Moreover, the nearby industrial area and dike were more polluted than the other areas, so the surface sediments in Sihwa lake should be monitored by taking into consideration the geological variations.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.1
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• pp.157-163
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• 2007

This paper presents a method to calculate generation power for integrating Sihwa tidal power into power systems. The sea levels of 1 minute interval using cubic interpolation based on the forecasted levels of high and low water offered from Nori(National Oceanographic Research Institute) are calculated. If the sea level is greater than the lake level and the difference between sea level and lake level at high tide is over the default value, it begins to calculate the tidal power. It is seen that tidal power can supply power to demand side stably and economically from assessment of effect for integrating tidal power into power systems.

• Proceedings of the KIEE Conference
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• 2006.11a
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• pp.375-377
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• 2006

This paper presents a method to calculate generation power for integrating Sihwa tidal power into power systems. The sea levels of 1 minute interval using cubic interpolation based on the forecasted levels of high and low water offered from Nori(National Oceanographic Research Institute) are calculated. If the sea level is greater than the lake level and the difference between sea level and lake level at high tide is over the default value, it begins to calculate the tidal power. It is seen that tidal power can supply power to demand side stably and economically from assessment of effect for integrating tidal power into power systems.

• Journal of Korean Society on Water Environment
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• v.27 no.4
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• pp.475-485
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• 2011

Lake Sihwa has a very unique watershed environment, surrounded by industrial, urban and rural catchment area with different land use. The first flush phenomenon was investigated in 3 catchment area. 4TG, representing the industrial area, shows rapid discharges of highly concentrated pollutants during the early stages of a storm and it is indicating a strong first flush effect. At AS, representing the urban area, the pollutant concentration reached its peak approximately 2~3 hours after the start of storm, which is a strong first flush effect did not appear. JJB and MS represent the rural areas, the PEMC analysis results suggest that highly concentrated pollutants were discharged during the middle and latter stages of a storm, instead of early pollutant runoff due to the effects of rainwater runoff.