• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.4
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• pp.462-472
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• 2023

We investigated the physio-chemical and geochemical parameters in the spraying shellfish aquacultures (Yeoja and Gangjin Bay) to establish the systematic strategy for effective environmental management. Spatial variation of each parameter showed partially significant difference (P<0.05) between Yeoja and Ganjin Bay, inferring the discriminative progress (i.e., accumulation and degradation) of the autochthonous organic matter within the aquaculture environments. We additionally integrated various properties (e.g., water/sediment quality, natural hazard, and biological health) which may affect the biological growth within the aquaculture habitats based on the biogeochemical cycles related to environmental components and aquaculture species. We used a screening approach (i.e., one out-all out; OOAO) which can permit the assessment of the health levels of aquaculture species, the scoring for other parameters (seawater, sediment, and natural hazard) as three levels (excellent, moderate and poor) depending on the complex interactive properties occurring in the aquaculture environments. Actual, discriminative scores obtained via our case studies may confirm that these stepwise processes are effectively evaluated for optimal health conditions within the aquaculture habitats. Thus, this approach may provide valuable insights for effective environmental management and sustainable growth of aquaculture operation.

• Advances in concrete construction
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• v.17 no.5
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• pp.293-310
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• 2024

Ultra-high-performance fiber-reinforced concrete (UHPFRC) is a form of cement-based material that has a compressive strength above 150 MPa, excellent ductility, and superior durability. This composite material demonstrates innovation and has the potential to serve as a viable substitute for concrete constructions that are subjected to harsh environmental conditions. Over many decades, extensive research and progressive efforts have introduced several commercial UHPFRC compositions globally. These compositions have been specifically designed to cater to an increasing variety of applications and meet the rising need for building materials of superior quality. However, the effective manufacturing of UHPFRC relies on the composition of its materials, especially the inclusion of fiber content and the proportions in the mixture, resulting in a more compact and comparatively uniform packing of particles. UHPFRC has notable benefits in comparison to conventional concrete, yet its use is constrained by the dearth of design codes and the prohibitive expenses associated with its implementation. The study demonstrates that UHPFRC presents a viable, long-lasting option for improving sustainable construction. This is attributed to its outstanding strength properties and superior durability in resisting water and chloride ion permeability, freeze-thaw cycles, and carbonation. The analysis found that a rheology-based mixture design technique may be employed in the production of UHPFRC to provide enough flowability. The study also revealed that the use of deformed steel fibers has shown enhanced mechanical qualities in comparison to straight steel fibers. However, obstacles such as higher initial costs, the requirement for highly specialized personnel, and the absence of comprehensive literature on global UHPFRC standards that establish minimum strength criteria and testing requirements can hinder the widespread implication of UHPFRC. Finally, this review attempts to deepen our foundational conception of UHPFRC, encourages additional study and applications, and recommends an in-depth investigation of the mechanical and durability properties of UHPFRC to maximize its practicality.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.27 no.4
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• pp.1-14
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• 2024

Otters, designated as Class I endangered wildlife due to population declines resulting from urban development and stream burial, have seen increased appearances in freshwater environments since the nationwide ban on stream filling in 2020 and the implementation of urban stream restoration projects. There is a pressing need for scientific and strategic conservation measures for otters, an umbrella and vulnerable species in aquatic ecosystems. Therefore, this study predicts potential otter habitats using the species distribution model MaxEnt, focusing on Hwangguji Stream in Suwon, and proposes conservation strategies. Otter signs were surveyed over three years from 2019 to 2021 with citizen scientists, serving as presence data for the model. The model's outcomes were enhanced by analyzing 'river nature map' as a boundary. MaxEnt compared the performance of 60 combinations of feature classes and regularization multipliers to prevent model complexity and overfitting. Additionally, unmanned sensor cameras observed otter density for model validation, confirming correlations with the species distribution model results. The 'LQ-5.0' parameter combination showed the highest explanatory power with an AUC of 0.853. The model indicated that the 'adjacent land use' variable accounted for 31.5% of the explanation, with a preference for areas around cultivated lands. Otters were found to prefer shelter rates of 10-30% in riparian forests within 2 km of bridges. Higher otter densities observed by unmanned sensors correlated with increasing model values. Based on these results, the study suggests three conservation strategies: establishing stable buffer zones to enhance ecological connectivity, improving water quality against non-point source pollution, and raising public awareness. The study provides a scientific basis for potential otter habitat management, effective conservation through governance linking local governments, sustainable biodiversity goals, and civil organizations.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.3
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• pp.228-234
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• 2008

The purpose of this study was to predict environmental distribution of anthracene, benzene, benzo[a]pyrene, 1-methylphenanthrene and phenanthrene in a four phase biopile system - air, water, soil and non aqueous phase liquid (NAPL) phase using level I fugacity model. Soil samples used for this study were collected from three sites in the United Kingdom which were historically contaminated with petroleum hydrocarbons. The level I fugacities (f) for the five contaminants were markedly different, however, the fugacities of each contaminant in three soil samples did not show significant difference. NAPL and soil were the dominant phases for all five contaminants. Results of this study indicated that difference in percentage of organic carbon strongly influenced the partitioning behavior of the cntaminants. The presence of benzene calls for an urgent need for risk-based management of air and water phase. Whereas insignificant amount of chemicals leached in the water phase for other organic contaminants showing greatly reduced potential of groundwater contamination. Furthermore, this study helped us to confirm the association of risk critical contaminants with the residual saturation in treated soils. They also can be used to emphasize the importance of accounting for the partitioning behavior of both NAPL and soil phases in the process of the risk assessment of the sites contaminated with petroleum hydrocarbons.

• The Journal of the Convergence on Culture Technology
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• v.8 no.5
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• pp.677-684
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• 2022

This study is a basic study to evaluate the ecological environment of Changwon City. The study site was 6 ecotourism districts in Changwon-si, and the ecotourism index was evaluated through direct visits and interviews with the person in charge through preliminary research and various literature data from June to July 2021. There are six ecotourism indicators: climate crisis, air quality improvement, water conservation, natural coexistence, citizen participation, and tourism resource management. When looking at the scores for the six ecotourism areas in Changwon, it received the highest score in the areas of natural coexistence and air quality improvement. However, the ecoregion received the lowest score in the water resource conservation category, indicating that the water resource conservation as a whole was weak. Next, tourism resource management, climate crisis, and citizen participation are at the same level in all regions. As a result of the evaluation through the low-carbon ecotourism index, the Changwon City low-carbon ecotourism certification system should first be operated as a measure to revitalize the ecotourism region. It is necessary to prepare a low-carbon ecotourism level for Changwon City. Second, it is very important to guide and promote ecotourism areas to revitalize ecotourism areas. Lastly, to operate a sustainable eco-environment area, it is necessary to operate using local governance above all else.

• Journal of Wetlands Research
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• v.21 no.2
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• pp.140-146
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• 2019

In order to manage non-point sources, the paradigm of the system should be changed so that the management of non-point sources will be systematized from the beginning of the use and development of the land. It is necessary to change the method of national subsidy support and poeration plan for the non-point source management area. In order to increase the effectiveness of the non-point source reduction project, it is necessary to provide a minimum support ratio and to provide additional support according to the performance of the local government. A new system should be established to evaluate the performance of non-point source reduction projects and to monitor the operational effectiveness. It is necessary to establish the related rules that can lead the local government to take responsible administration so that the local governments faithfully carry out the non-point source reduction project and achieve the planned achievement and become the sustainable maintenance. Alternative solutions are needed, such as problems with the use of $100{\mu}m$ filter in automatic sampling and analysis, timely acquisition of water sampling and analysis during rainfall, and effective management of non-point sources network operation management. As an alternative, it is necessary to consider improving the performance of sampling and analysis equipment, and operate the base station. In addition, countermeasures are needed if the amount of pollutant reduction according to the non-point source reduction facility promoted by the national subsidy is required to be used as the development load of the TMDLs. As an alternative, it is possible to consider supporting incentive type of part of the maintenance cost of the non-point source reduction facility depending on the amount of pollutants reduction.

• Journal of Korea Water Resources Association
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• v.48 no.4
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• pp.309-319
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• 2015

River characteristics in South Korea has been affected by seasonal climatic variability due to climate change and by remarkable land cover change due to rapid economic growth. In this regard, the roles of river management is getting more important to eco-system and human community in watersheds of South Korea. Understanding river characteristics including direct runoff and baseflow, the first step of river management, can give a significant contribution to sustainable river environment. Therefore, the objective of this study is to quantify the contributions of the direct runoff and baseflow to river streamflow. For this, we used the BFLOW and WHAT programs to conduct baseflow separation for 71 streamflow gauge stations in Han River system, South Korea. The results showed that baseflow index for 71 stations ranges from 0.42 to 0.78. Also, gauge stations which have baseflow index more than 0.5 occupied 76% of a total stations. However, baseflow index can be overestimated due to human impacts such as discharge from dams, reservoirs, and lakes. This study will be used as fundamental information to understand river characteristics in river management at the national level.

• Ecology and Resilient Infrastructure
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• v.9 no.3
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• pp.131-140
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• 2022

The magnitude and frequency of extreme floods are increasing owing to the effects of climate change. Therefore, multipurpose flood management techniques incorporating nature-based solutions have been introduced to mitigate the limitations of flood management and river design methods relying on existing observation data. Nature-based solutions to prepare for such extreme flooding events include ways to retreat the embankment, expand the floodplain, and reduce flood damage. To apply these technologies, adopting appropriate location selection methods based on various evaluation factors, such as flood damage reduction effects, sustainable ecological environments, river connectivity, and physical channel structure enhancements, should be prioritized. Therefore, in this study, the optimal location for implementing the multipurpose floodplain construction project was determined by selecting the location of the floodplain expansion with objectivity in the river waterfront area upstream of Daecheong Dam to downstream of Yongdam Dam. Through the final location determination, the Dongdaeje and Jeogokje sections were included in the optimal location considering both flood damage reduction and water environment improvement.

• Journal of Wetlands Research
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• v.25 no.4
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• pp.267-273
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• 2023

Algae are an important component of the ecosystem. However, the excessive growth of cyanobacteria has various harmful effects on river environments, and diatoms affect the management of water supply processes. Algal monitoring is essential for sustainable and efficient algae management. In this study, an object detection model was developed that detects and classifies images of four types of harmful cyanobacteria used for the criteria of the algae alert system, and one diatom, Synedra sp.. You Only Look Once(YOLO) v8, the latest version of the YOLO model, was used for the development of the model. The mean average precision (mAP) of the base model was analyzed as 64.4. Five models were created to increase the diversity of the input images used for model training by performing rotation, magnification, and reduction of original images. Changes in model performance were compared according to the composition of the input images. As a result of the analysis, the model that applied rotation, magnification, and reduction showed the best performance with mAP 86.5. The mAP of the model that only used image rotation, combined rotation and magnification, and combined image rotation and reduction were analyzed as 85.3, 82.3, and 83.8, respectively.

• Journal of Environmental Impact Assessment
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• v.17 no.2
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• pp.97-103
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• 2008

This study presented politic proposals and diverse utilization-type in coastal areas by analyzing results of reviewed related-statements of marine environment during the one year period of 2007 by Marine Environmental Impact Assessment Center. Total of 358 cases were reviewed, which was a significant increase from 270 in 2006. Consultation on the utilization of sea areas (CUSA) accounted for the largest number of 165 (46.1%) and it was followed by 104 cases of environmental impact assessment (EIA) (29.0%) and 89 cases of prior environmental review (PER) (24.9%). As such, evaluation statements (EIA+PER) related to consultations of the Ministry of Environment accounted for approximately 54% of the entire cases reviewed. To analyze the overall results of reviewing marine-related evaluation statements, utilization and planning were conducted by 47.9%, 38.4% and 13.7% in the South Sea, West Sea and East Sea of Korea, respectively. In evaluation statements (EIA+PER), port construction, industrial complex construction, urban management plan and road construction took up most of the part by 40.9%, 20.2%, 10.4% and 7.3%, respectively. In terms of CUSA-statement, it was evaluated that consultations were mostly carried out on use and reclamation of public water surface in coastal areas and on sea aggregate extraction process in EEZ. The largest number of plans for coastal use were established for Jeollanam-do, followed by Gyeongsangnam-do, Chungcheongnam-do, Gyeongsangbuk-do and Gyeonggi-do. In particular, development plans were concentrated on Jeollanam-do and Gyeongsangnam-do with stable marine environment and outstanding view of the nature. In most cases, these regions are adjacent to the areas designated as a sea area for environmental management and fisheries resources protection zone. Therefore, conflicts exist between development and preservation. Also, rather than random development, more detailed marine environmental impact assessment, gathering of public opinions and politic harmony are essentially required. For efficient coastal management and environmentally sound and sustainable development, fulfilling consistent and transparent coastal policies as well as active and reliable decision making to center on coastal environment by management bodies will be important.