• Journal of Environmental Impact Assessment
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• v.30 no.4
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• pp.225-236
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• 2021

The master plan for the Four Rivers Restoration Project (June 2009) was devised, the procedure of pre-environmental review (June 2009) and environmental impact assessment (Nov. 2009), and post-environmental impact survey were implemented, and 4 times audits also inspected. and finally the Ministry of Environment's Four Rivers Investigation and Evaluation Planning Committee proposed the dismantling or partial dismantling of the five weirs of the Geum River and Yeongsan River. But controversies and conflicts are still ongoing. Therefore, this study intend to reestablish the management plan for the four major rivers by reviewing and analyzing the process so far. The results are as follows. First, a cost-benefit analysis should be performed by comparing the water quality impact of weir operation and weir opening. Therefore, it is inevitably difficult to conduct cost-benefit analysis. Second, according to the results of cost-benefit analysis on the dismantling of the Geum River and the Yeongsan River, the dismantling of the weir and the regular sluice gate opening was decided. However, there is a problem in the validity of the decision to dismantle the weir because the cost-benefit analysis for maintaining the weir is not carried out. Third, looking at the change in water quality of 16 weirs before and after the Four Major Rivers Restoration Project, COD and Chl-a were generally deteriorated, and BOD, SS, T-N, and T-P improved. However, in the cost-benefit analysis related to water quality at the time of weir dismantling, only COD items were targeted. Therefore, the cost of BOD, SS, T-N, and T-P items improved after the project were not reflected in the cost-benefit analysis of dismantling weirs, so the water quality benefits were exaggerated. Fourth, in the case of Gongju weir and Juksan weir, most of them are movable weirs, so opening the weir alone can have the same effect as dismantling when the water quality deteriorates. Since the same effect can be expected, there is little need to dismantle the weirs. Fifth, in order to respond to frequent droughts and floods, it is desirable to secure the agricultural water supply capacity to the drought areas upstream of the four majorrivers by constructing a waterway connected to the weir. At present it is necessary to keep weirs rather than dismantling them.

• Journal of the Korean Institute of Landscape Architecture
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• v.30 no.6
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• pp.57-65
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• 2003

This study researches attributes , behaviors , satisfaction factors and degrees of curiosity of visitors to recreational forests in the suburbs of a large city. It aims to present suggestions for urban forest development and management policy by offering basic data which help to plan, design and manage recreational forests to increase the quality of these environments. The results are as follows First, in attribute, the visiting rate of males is higher than that of females, and the main users are in their thirties and forties. Sixty percent of visitors graduated from university and their rate of employment is evenly distributed. 95 percent of visitors are residents of the metropolitan area. In terms of behavior, major visitors are family units visiting during summer seasons and for overnight stays. 75% are re-visitors. 85% of visitors came to escape the city with families and friends, keep in good health and experience nature. Second, to extract the factors affecting visitor satisfaction in recreational forests, the natural environment, facilities, and management/use systems were identified as independent variables, while subordinate satisfactions were dependent variables. so regression analysis was used. Thus, the variables affecting the natural environment are quality of water, stream use, biodiversity, fresh air and landscape factors. The variables affecting facilities are puking, convenience, play facilities, sanitary arrangement and camping. Most important among the variables affecting management/use systems are educational facilities and access condition. On the basis of generalizing the study in the existing individual site, we must verify the visiting characteristics in recreational forests in the suburbs of a large city. Since development of recreational forests is understood as a sequence considering a site and a given condition, and since management and improvement must unfold according to these characteristics, a strategy is needed to reveal visitors' opinions about the site. Depending on the facilities and service, satisfaction of recreational forests is generally influenced by social and economic qualities. Also, this study can look into the effect according to use pattern motive and season. As suburban recreational forests have many overnight-users and younger men, programs suitable for these groups are needed. On the basis of variables affecting satisfaction according to natural environment, facilities, and use system, policies which can manage the natural environment and introduce educational programs are needed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.5B
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• pp.475-481
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• 2011

The TMDL standard flow as applying watershed management regime uses the average low flow of past 10 years. Moreover, the TMDL implementation assessment has been enforced through management of pollutant load satisfied objective water quality. Even though the present allocation and management through averaged low flow are still convenient, they are not enough to solve ultimate goals of watershed management to keep up recovery of water body. To maintain the same water quality concentration, the standard flow is required to consider total discharge in management plan which helps to keep healthy ecosystem. In view of this, it would be possible to approach reasonable assessment by reflecting variably changeable discharge from precipitation-streamflow relation and the TMDL standard establishment considering artificial regulated flow. Therefore, this study attempts to develop the TMDL method using Load Duration Curve (LDC) and Streamflow-Load Rating Curve (QLRC) considering total discharge and finds drawbacks with solutions as applying on Nakdong river TMDL unit watershed. Finally, this research evaluates possibility of application on pollutant load allocating and implementation assessment in Korea.

• Journal of the Korean Society of Safety
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• v.35 no.6
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• pp.85-92
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• 2020

Wet Scrubber reacts the incoming pollutant gas with cleaning water (water + absorbent) to absorb pollutants and release the clean air to the atmosphere. Wet scrubbers and packed tower scrubbers using this principle are widely used in businesses that emit acid gases. In particular, in the etching process using hydrochloric acid (HCl), alkaline washing water (NaOH) having a pH of about 8 to 11 is used to absorb a large amount of acid gas. However, These salts are attached to the injection nozzle (nozzle), filling material (packing), and the demister (Demister), causing air pollution, human damage, and inoperability due to clogging and acid gas discharge. Therefore, In this study, an improvement plan was proposed to manage the washing water with pH 3~4 acidic washing water. The test method takes samples from the Wet Scrubber flue measurement laboratory twice a month for 1 year. Hydrogen chloride (HCl) concentration (ppm) was measured, and nozzle clogging and scale conditions were measured, compared, and analyzed through a differential pressure gauge and a pressure gauge. As a result of the check, it was visually confirmed that the scale was reduced to 50% or less in the spray nozzle, filler, and demister. In addition, the emission limit of hydrogen chloride in accordance with the Enforcement Regulation of the Air Quality Conservation Act [Annex 8] met 3 ppm or less. Therefore, even if the washing water is operated in an acidic pH range of 3 to 4, it is expected to reduce air pollution and human damage due to clogging of internal parts, and it is expected to reduce maintenance costs such as regular cleaning or replacement of parts.

• Journal of Korea Water Resources Association
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• v.40 no.6 s.179
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• pp.469-483
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• 2007

Nitrate and chloride are the most common contaminants in groundwater and their concentrations increase easily due to fertilizer consumption and urbanization. The number of time series data for groundwater quality at a single site was not sufficient to analyze trends on Jeju Island. Therefore rectangle grids were drawn for the whole island and single grid was determined to be $500m{\times}500m$ after considering similar stream density, homogeneous hydraulic coefficients, geologic features of volcanic rock and low topographic slopes. All data within each lattice were collected and arranged in time series order and analyzed using Sen's method. 10.6 % of the total lattices for chloride and 22.4% for nitrate showed upward trends from the early 1990's to the early 2000's. Especially, upward trends for nitrate concentration are distinct in the low mid-mountainous areas of western and southern watersheds. Many septic tanks and much domestic waste from the urbanization of the low mid-mountainous area have produced this upward trend. Additionally, the agricultural region has dramatically increased since the 1990's and this has led to an increase of fertilizer consumption and, as a result, nitrate concentration. Therefore, the target of any management plan for groundwater quality on Jeiu Island needs to be focused on careful land use decisions in the mid-mountainous areas which are near Halla Mountain.

• Journal of Environmental Impact Assessment
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• v.12 no.3
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• pp.189-198
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• 2003

The purpose of this paper is to evaluate the groundwater pumping capadty at a catchment area containing interrelated wells without considering their qualities by using numerical simulation in Miyake Island, young volcanic island with very complicated hydro-geological formations. The groundwater pumping capadties of each well and over entire study area were estimated as the IMY(i,t) by individual withdrawals and the SSMY(t) by simultaneous withdrawals. These results can be used to secure a sure source for taking a plan for supplying water use in young volcanic island as Miyake Island. In simultaneous withdrawals, the withdrawals from well no. 5 and 6 should have the roles as the barrier wells against the intrusion of the groundwater of the part adjacent to Tairo Pond into the inner part of study area. Therefore, it can be suggested to adopt the simultaneous withdrawals as the optimal approach of groundwater management for supplying water use with respect to quantity and quality.

• Journal of Environmental Science International
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• v.12 no.8
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• pp.841-846
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• 2003

The ecosystem model was applied to estimate the regional distribution of the net production(or consumption) of phytoplankton and the net uptake(or regeneration) rate of nutrients in Masan Bay for scenario analysis to find a proper management plan. At the surface level, net production of phytoplankton is 200 mgC/㎡/day at the entrance of the bay, and 400∼1000 mgC/㎡/day at the center of the bay. The inner area of the bay showed more than 2000 mgC/㎡/day. All areas of the bottom level have a net consumption, with the center of the bottom level showing more than 600 mgC/㎡/day. For dissolved inorganic nitrogen, the results showed a net uptake rate of 100∼900 mg/㎡/day at the surface level. It showed that the net regeneration is above 50 mg/㎡/day at the bottom level. For dissolved inorganic phosphorus, the net uptake rate showed 10.0∼80.0 mg/㎡/day at the surface level, and the regeneration rate showed 0∼20.5 mg/㎡/day at the bottom level. Therefore, in order to control the water quality in Masan Bay, it is important to consider the re-supplement of nutrients regenerated in the water column.

• Journal of Environmental Impact Assessment
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• v.17 no.3
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• pp.201-211
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• 2008

According to IPCC fourth assessment report in 2007, global mean temperatures have risen by 0.74 degrees Celsius over the past 100 years. Moreover, in the recent 25 years, global mean temperatures have risen by 0.45 degrees Celsius, which is 2.4-times larger than those in the past 100 years. The evidences for climate change, such as sea level rise, arctic glacier melt, and desertification in Asia, have occurred and increased over the globe. In Korea, because regional climate has been changed, types of agriculture and fishery should be replaced. And as precipitation pattern behave differently from the past decades, water management would be more difficult, furthermore, atmospheric environment, related to concentrations for ozone, sulfate, etc., could be worse. Nevertheless, we have only focused on greenhouse gas reduction duty for the Convention of Climate Change. Fortunately, in the fourth plan on climate change, we have planned to manage climate change more actively since 2007. In Korea, the emission of carbon dioxide has increased about 1.9-times more, from 311million ton in 1990 to 591million ton in 2004. And also about 2 ppm rise every year for concentrations of carbon dioxide in the atmosphere. As a result, ecosystem, quality of water and atmosphere would be affected. Here, the emission of greenhouse gases over the globe is examined, and the effect of greenhouse gases for climate change is reviewed from the results of previous studies. In addition, the countermeasures of mitigation and adaptation on climate change were discussed for the understanding.

• Journal of Environmental Impact Assessment
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• v.22 no.2
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• pp.183-194
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• 2013

The Ministry of Environment, Ministry of Agriculture, Fishery and Forestry, and Ministry of Construction, Transportation and Maritime Affairs are in charge of livestock manure management. There are national statistics regarding the livestock industry such as the National Pollution Source Survey, Livestock Statistic Survey, and Livestock-breeding Trend Survey. The current statistical data are focused on the scale of livestock breeding and the production of livestock manure using these data, but it is difficult to establish database due to lack of information. In order to plan relevant policies including management of livestock manure, the government established database systems such as the integrated information system of livestock manure, the integrated system of national infectious animal-disease prevention, and the Sae-ol public administrative system. We have tried to suggest improvements for the comprehensive environmental information system of livestock manure management by detecting problems in each level of the livestock manure life-cycle, making use of the existing systems, and considering the electronic transfer system of livestock manure. The services and functions of this comprehensive system include information of livestock farmers, the production, collection, transportation, and treatment of livestock manure, the area of agricultural land used for livestock manure, the report of approval and results on livestock manure products, management of statistical information, management of civil affairs, and relevant mobile application services. The system is made up of three processes: first, establishment of GIS-based management database of livestock manure; second, establishment of a history management system for livestock manure transactions; and third, development of a water quality assessment system.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.26 no.1
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• pp.41-50
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• 2008

Recent progress in state-of-the-art geospatial information technologies such as digital mapping, LiDAR(Light Detection And Ranging), and high-resolution satellite imagery provides various data sources fer Digital Elevation Model(DEM). DEMs are major source to extract elements of the hydrological terrain property that are necessary for efficient watershed management. Especially, watersheds extracted from DEM are important geospatial database to identify physical boundaries that are utilized in water resource management plan including water environmental survey, pollutant investigation, polluted/wasteload/pollution load allocation estimation, and water quality modeling. Most of the previous studies related with watershed extraction using DEM are mainly focused on the hydrological elements analysis and preprocessing without considering grid size of the DEMs. This study aims to analyze accuracy of the watersheds extracted from DEMs with various grid sizes generated by LiDAR data and digital map, and appropriate preprocessing methods.