• Journal of Navigation and Port Research
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• v.44 no.6
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• pp.488-493
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• 2020

In this study, we sought to establish a vessel-discharge pollutant-treatment system recommended by IMO by first investigating advanced facilities overseas to help us understand and evaluate our domestic facility and needs. IMO recommends the installation and operation of port pollutant-storage facilities to adequately treat pollutants emitted by ships entering the port, and we reviewed the registration and operation of these facilities in IMO member countries, focusing on the IIII Code. Due to recent environmental regulations, additional facilities are required to treat the washing water discharged from equipment such as scrubbers mounted on the ship so pollutant-storage facilities must be established. Currently, Korea's ship-discharged wastes are being moved from ports to land waste-treatment plants, and their quantity and properties are not being monitored. Therefore, in this study, we improved monitoring of the discharged pollutants and investigated the proper arrangement of pollutant storage facilities as recommended by IMO. The system we established can help provide smooth service to incoming ships - and appropriate treatment of pollutants and will greatly benefit international maritime operations.

• Journal of the Korean Applied Science and Technology
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• v.38 no.3
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• pp.903-913
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• 2021

Three-type PVC membranes denoted by AEM-1, AEM-2, and AEM-3 with a cross-linked anion-exchange group were prepared by substitution reaction of PVC with triethyldiamine (TEDA), 1,4-dimethylpiperazine (DMP), and 1,4-bis(imidazol-1-ylmethyl)benzene (BIB) in cyclohexanone, respectively. We confirmed the successful preparation of the AEM-1, AEM-2, and AEM-3 via ionic conductivity (S/cm), water uptake (%), contact angle, ion-exchange capacity (m_eq/g), thermal properties, SEM and XPS analysis, respectively. The electrochemical capacitor experiments using PVC membrane with cross-linked anion-exchange group in organic electrolytes were performed. The prepared AEM-1, AEM-2 AEM-3 have a good stability by charge and discharge performance in organic electrolyte. As a result, the AEM-2 and AEM-3 membrane based on PVC prepared by the solvent casting method after substituent reaction is suitable for the use as a separator in organic electrochemical capacitor (supercapacitor).

• Ecology and Resilient Infrastructure
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• v.8 no.1
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• pp.44-53
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• 2021

The flood prevention capacity of drainage facilities in urban areas has weakened because of the increase in impervious surface areas downtown owing to rapid urbanization as well as localized heavy rains caused by climate change. Detention can be installed in trunk sewers and linked to existing drainage facilities for the efficient drainage of runoff in various urban areas with increasing stormwater discharge and changing runoff patterns. In this study, the concept of detention in trunk sewers, which are storage facilities linked to existing sewer pipes, was applied. By selecting a virtual watershed with a different watershed shape, the relationship between the characteristic factors of detention in the trunk sewer and the design parameters was analyzed. The effect of reducing stormwater runoff according to the installation location and capacity of the reservoir was examined. The relationship between the installation location and the capacity of the detention trunk sewer in the Dowon district of the city of Yeosu, South Korea was verified. The effects of the existing water runoff reduction facility and the detention trunk sewer were also compared and analyzed. As a result of analyzing the effects of reducing internal inundation, it was found that the inundation area decreased by approximately 66.5% depending on the installation location of the detention trunk sewer. The detention trunk sewer proposed in this paper could effectively reduce internal inundation in urban areas.

• Journal of the Korean earth science society
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• v.43 no.2
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• pp.303-311
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• 2022

Gadolinium, commonly used as a contrast agent for magnetic resonance imaging (MRI), is discharged into aquatic environments without removal after treatment in wastewater treatment plants (WWTPs) because of its high stability. In this study, we collected water samples from Suyeong WWTP, Busan, to investigate the dissolved rare earth element (REE) removal capacity of each wastewater treatment process and to evaluate the discharge of anthropogenic Gd (Gd_anth) from effluents. As wastewater passed through each stage of treatment, the concentrations of light REEs (La-Eu) decreased, whereas those of heavy REEs (Tb-Lu) were relatively consistent. Negative Sm anomalies (<1) were observed in several samples, indicating that Sm can be removed by adsorption onto particles or phosphate during the biological removal process. Positive Gd anomalies (149±50, n=9) were observed in all samples. The ratios of Gd_anth concentrations to measured Gd concentrations in all wastewater treatment processes were higher than 97%. This indicates that Gd_anth was discharged to the Suyeong River without removal during the wastewater treatment process. Considering the daily treatment capacity in each process, the total flux of Gd_anth was estimated to be 259 mmol/day. Our results suggest that mid- and/or long-term monitoring of Gd is needed because Gd_anth is continuously discharged into Suyeong Bay through WWTPs.

• Ecology and Resilient Infrastructure
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• v.10 no.2
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• pp.40-49
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• 2023

To reduce the damage of extreme flooding caused by climate change and to create flood mitigation sections in a nature-friendly riparian area, it is necessary to restore the floodplain area by referring to the past floodplain section of the current inland waterfront area before the levee was built. This study proposed a method of selecting a location for floodplain restoration using old maps of the Geum River study section and analyzed the effect of flood level reduction through unsteady flow numerical simulations using the floodplain as a flood mitigation space. As a result of analyzing changes in the river areas using old maps, the river section was estimated to gradually reduce by 27.8% (1,059,380 m²) in 2020 compared to 1919, and it was found to have an effective storage capacity of 2,200,868 m³ when restored to offline storage. The flood level and discharge control effects analyzed based on HEC-RAS unsteady flow simulation were 16 cm and 219.01 m³/s, respectively, in the downstream cross-section. In the numerical simulation in this paper, the flood mitigation space was applied as an offline reservoir. The effect of reducing the flood level may differ if levee retreat/relocation is applied.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.2B
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• pp.215-224
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• 2008

The effect of streamflow considering future land use change and vegetation index information by climate change scenario was assessed using SLURP (Semi-distributed Land-Use Runoff Process) model. The model was calibrated and verified using 4 years (1999-2002) daily observed streamflow data for the upstream watershed ($260.4km^2$) of Gyeongan water level gauging station. By applying CA-Markov technique, the future land uses (2030, 2060, 2090) were predicted after test the comparison of 2004 Landsat land use and 2004 CA-Markov land use by 1996 and 2000 land use data. The future land use showed a tendency that the forest and paddy decreased while urban, grassland and bareground increased. The future vegetation indices (2030, 2060, 2090) were estimated by the equation of linear regression between monthly NDVI of NOAA AVHRR images and monthly mean temperature of 5 years (1998-2002). Using CCCma CGCM2 simulation result based on SRES A2 and B2 scenario (2030s, 2060s, 2090s) of IPCC and data were downscaled by Stochastic Spatio-Temporal Random Cascade Model (SST-RCM) technique, the model showed that the future runoff ratio was predicted from 13% to 34% while the runoff ratio of 1999-2002 was 59%. On the other hand, the impact on runoff ratio by land use change showed about 0.1% to 1% increase.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.1B
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• pp.153-160
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• 2008

To estimate microbial contaminant loading discharged from diffuse sources, rainfall runoff of six rainfall events were monitored at three study watersheds of forestry and agricultural land use. Monitored indicator microorganism constituents were total coliform (TC), fecal coliform (FC), Escherichia coli (EC), and fecal streptococcus (FS). Soil loss during elevated flow rate caused higher suspended solid concentrations. Indicator microorganism concentrations were closely related with flow rate. TC event mean concentration (EMC) from unpolluted forestry was $5.3{\times}10^3CFU/100ml$, FC EMC was $1.4{\times}10^3CFU/100ml$, EC EMC was $1.1{\times}10^3CFU/100ml$, and FS EMC was $2.9{\times}10^2CFU/100ml$. From a watershed with agricultural-forestry land use, TC EMC was $1.7{\times}10^5CFU/100ml$, FC EMC was $8.5{\times}10^4CFU/100ml$, EC EMC was $8.9{\times}10^4CFU/100ml$, and FS EMC was $3.4{\times}10^4CFU/100ml$. Mixed land use of agricultural-forestry with bigger area, TC EMC was $1.9{\times}10^5CFU/100ml$, FC EMC was $9.6{\times}10^4CFU/100ml$, EC EMC was $7.0{\times}10^4CFU/100ml$, and FS EMC was $5.1{\times}10^4CFU/100ml$.

• Ecology and Resilient Infrastructure
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• v.10 no.4
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• pp.217-225
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• 2023

This study analyzed the effect of flood level reduction in the case of creating and operating offline storage for the Jangdong district, which can be used as a flood buffer space for the Geumgang River, through one-dimensional unsteady flow numerical simulation. In particular, the sensitivity analysis of changes in the height and width (length) of transverse weirs on flood level changes was performed to provide quantitative information necessary for flood control facility (embankment) design. As a result of analyzing the flood control effect of the offline storage based on the peak flood discharge and level, spatially, the flood control effect at the planned flood buffer space site and the downstream end was confirmed, and it was confirmed that the flood reduction effect at the downstream occurred the most. By design conditions of the transverse overflow weir, the greatest flood reduction effect was found under the condition that the overflow weir height based on the 50-year frequency flood level and the transverse overflow weir width (length) of 125 m were considered. The effect of delaying the time to reach the maximum flood due to the operation of the offline storage site was also presented based on unsteady flow modeling.

• Journal of the Korean GEO-environmental Society
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• v.24 no.12
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• pp.31-38
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• 2023

In this study, runoff characteristics analysis was conducted as a basic research to establish a forecasting and warning system for flood risk areas in small mountainous basins in South Korea. The Danyang 1 Bridge basin located in Danyang-gun, Chungcheongbuk-do was selected as the study basin, and the watershed characteristic factors were calculated using Q-GIS based on the digital elevation model (DEM) of the basin. In addition, nine heavy rainfall events were selected from 2020 to 2023 using hydrometeorological data provided by the National Water Resources Management Comprehensive Information System. HEC-HMS rainfall-runoff model was used to analyze the runoff characteristics of small mountainous basins, and rainfall-runoff model simulation was performed by reflecting 9 heavy rainfall events and calculated basin characteristic factors. Based on the rainfall-runoff model, parameter optimization was performed for six heavy rain events with large error rates among the simulated events, and the appropriate parameter range for the Danyang 1 Bridge basin, a small mountainous basin, was calculated to be 0.8 to 3.4. The results of this study will be utilized as foundational data for establishing flood forecasting and warning systems in small mountainous basin, and further research will be conducted to derive the range of parameters according to basin characteristics.

• Korean Journal of Environment and Ecology
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• v.38 no.2
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• pp.178-188
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• 2024

The dynamics of suspended sediment (SS) in forested catchments vary depending upon human or natural disturbances, including land use change, forestry activity, forest fires, and landslides. Understanding the dynamics of SS originating from the potential sources within a forested catchment is crucial for establishing an effective water quality management strategy. Therefore, to suggest a systematic method for interpreting SS dynamics, we evaluated the performance and applicability of ten methods for calculating the hysteresis index based on observed hydrological data and two calculation models (Lawler's method and Lloyd's method) with five sampling intervals (50th, 25th, 10th, 5th, and 1st percentiles). Our results showed that Lloyd's method, which used a sampling interval at the 1st percentile, had the largest number of analyzable runoff events and exhibited the best performance. The results of this study can contribute to quantifying the hysteresis in the relationship between discharge and SS and provide useful information for interpreting SS dynamics.