• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.4
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• pp.123-132
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• 2018

The purpose of this study was to evaluate the reduction effect of non point source (NPS) pollution in Haean highland agricultural catchment ($62.8km^2$) for 13 BMP scenarios under RCP (Representative Concentration Pathway) 4.5 and 8.5 scenarios. Under the present climate condition, the BMP (best management practices) reduction efficiency of SS (suspended solid), T-N (total nitrogen), and T-P (total phosphorus) showed +25.7%, +4.2%, and +16.1% for VFS (vegetative filter strip), +0.1%, +15.6%, and +5.7% for FC (fertilizer control), and +6.3%, -2.9%, and +3.9% for RSM (rice straw mulching) respectively. In general, effective was the best for SS and T-P reductions, and the FC was the best for T-N reduction. The negative effect of T-N on RSM was induced by increase in infiltration and solute transport to baseflow. Under the future climate change scenarios, the SS, T-N, and T-P reduction efficiency showed the range of +1.9~+11.6%, -1.9~+0.2%, and +5.3~+11.9% respectively. The 3 BMPs (VFS, FC, and RSM) application in the future showed negative and little differences (-0.5~+1.6%) for SS and T-N reduction efficiencies while T-P reduction efficiency showed +0.3~+7.6% comparing with the baseline period. To achieve an increase in the reduction efficiency of future SS and T-N by +2~+10%, the combined application of more than two BMPs is necessary.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.27 no.1
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• pp.1-16
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• 2024

The riparian area plays a crucial role in maintaining the balance between the aquatic and terrestrial ecosystems. The Korean government has recognized the importance of protecting riparian areas and has taken steps to purchase land and create ecobelt to reduce non-point source pollutants(NSPs) that can negatively impact water quality. However, selecting the catchment area and calculating the pollution load can be challenging due to the small area of the purchased land and the limitations of low-resolution DEMs. To address these challenges, this study proposes the use of unmanned aerial vehicles(UAVs) to create a high-resolution DEM and calculate the pollution load through land cover analysis. This approach can provide a more accurate representation of the land use status and help to identify areas that are contributing to NSPs. The quantitative comparison of the difference in water quality improvement ecosystem services according to the scenarios of additional catchment areas shows that even land purchased for the same amount of money may have different ecosystem service values, and this was quantitatively calculated. This can be used to prioritize future land acquisition. Overall, this study's approach could provide valuable insights into the effectiveness of ecobelt in reducing NSPs and inform future efforts to protect riparian areas in Korea and beyond.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.3
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• pp.400-407
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• 2011

To evaluate the aquatic ecological characteristics in Sinpyongcheon constructed wetlands for treating nonpoint source pollution, the removal rates of nutrients in water, the total amounts of T-N and T-P uptakes by water plants, and chemical characteristics of T-N and T-P in sediment were investigated. The concentrations of BOD, COD, SS, T-N and T-P in inflow were 0.07~1.47, 0.60~2.65, 0.50~4.60, 1.38~6.26 and $0.08{\sim}0.32mg\;L^{-1}$, respectively. The removal rates of BOD, COD, SS, T-N, and T-P were 14%, 6%, 18%, 24%, and 10%, respectively. The maximum amount of T-N uptake by water plants in August was $813mg\;plant^{-1}$ for Phragmites communis TRIV in $2^{nd}$ bed, $1,172mg\;plant^{-1}$ for Typha orientalis PRESL in $3^{rd}$ bed, respectively. The maximum amount of T-P uptake by water plants in August was $247mg\;plant^{-1}$ for Phragmites communis TRIV in $2^{nd}$ bed, $359mg\;plant^{-1}$ for Typha orientalis PRESL in $3^{rd}$ bed, respectively. Organic matter, T-N, and T-P contents in sediments were high in the order of $1^{st}$ bed > $2^{nd}$ bed > $3^{rd}$ bed. Microbial biomass C/N/P ratios in sediments in $1^{st}$, $2^{nd}$, and $3^{rd}$ were 78~110/3~6/1, 73~204/1~6/1, and 106~169/1~6/1, respectively.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.5
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• pp.557-564
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• 2009

A combined sewer system can quickly drain both storm water and sewage, improve the living environment and resolve flood measures. A combined sewer system is much superior to separate sewer system in reduction of the non-point source pollutant load. However, during rainfall. it is impossible in time, space and economic terms to cope with the entire volume of storm water. A sewage system that exceeds the capacity of the sewer facilities drain into the river mixed with storm-water. In addition, high concentration of CSOs by first-flush increase pollution load and reduce treatment efficiency in sewage treatment plant. The aim of this study was to develope a processing unit for the removal of high CSOs concentrations in relation to water quality during rainfall events in a combined sewer. The most suitable operational design for processing facilities under various conditions was also determined. With a designed discharge of 19.89 m/min, the removal efficiency was good, without excessive overflow, but it was less effective in relation to underflow, and decreased with decreasing particle size and specific gravity. It was necessary to lessen radius of vortex separator for increasing inlet velocity in optimum range for efficient performance, and removal efficiency was considered to high because of rotation increases through enlargement of comparing height of vortex separator in diameter. By distribution of influent particle size, the actual turbulent flow and experimental results was a little different from the theoretical removal efficiency due to turbulent effect in device.

• Journal of Wetlands Research
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• v.11 no.2
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• pp.55-66
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• 2009

The increase of pollutant loadings from nonpoint sources affect the water quality of the major rivers in Korea. Consequently, the need for managing the nonpoint source (NPS) pollution becomes the main concern of the Korean Ministry of Environment (MOE). Recently, the policy was changed from pollutant concentration-restricting approach to the total maximum daily load (TMDL) approach to improve the water quality and protect the aquatic ecosystem. Part of the program is the construction of Best Management Practice (BMP) pilot facilities basically to control NPS. Most of the BMPs adopted were foreign technologies which could not be properly employed in the country due to some limitations such as climate, watershed characteristics, etc. In other words, to be able to apply the BMPs, research on its applicability is necessary. In this study, a three-year monitoring has been conducted to assess the treatment performance of the BMP installed in highway toll plaza and parking lot. The data gathered aid in the characterization of NPS pollutants in runoff and estimation of the pollutant removal efficiency of the BMP. The results will be used for the future implementation of BMP in different land uses as well as for the determination of optimum operation and maintenance.

• Journal of The Korean Society of Agricultural Engineers
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• v.63 no.2
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• pp.51-60
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• 2021

Effective nonpoint source (NPS) pollution management requires frequent water quality monitoring, which is, however, often costly to be implemented in practice. Statistical techniques and machine learning methods allow us to identify and focus on fundamental environmental variables that have close relationships with NPS pollutants of interest. This study developed surrogate models to predict the concentrations of suspended sediment (SS) and total phosphorus (T-P) from turbidity and runoff discharge rates using multiple linear regression (MLR) and random forest (RF) methods. The RF models provided acceptable performance in predicting SS and T-P, especially when runoff discharge rates were high. The RF models outperformed the MLR models in all the cases. Such finding highlights the potential of RF techniques and models as a tool to identify fundamental environmental variables that are measured in relatively inexpensive ways or freely available but still able to provide information required to quantify the concentrations of NP S pollutants. The analysis of relative importance rates showed that the temporal variations of SS and T-P concentrations could be more effectively explained by that of turbidity than runoff discharge rate. This study demonstrated that the advanced statistical techniques such as machine learning could help to improve the efficiency of NPS pollutants monitoring.

• Journal of Wetlands Research
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• v.18 no.4
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• pp.363-377
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• 2016

This study was investigated the pollutant load, contamination properties, pollution condition of the fine parts of tributary, the influence of Nakdong river watershed and etc. in the tributaries. The contaminated tributaries were that among the Kumho and Nam river or were too far from site of water quality monitoring stations, regularly. As a result, the water quality level was almost similar between Nam and Kumho River, except for certain parameter including TN(Total Nitrogen), Chl-a(Chlorophyll-a) and SS(Suspended Solid) in which Kumho river were 20~120%. The point discharge load(kg/day) and load density ($kg/day/km^2$) of tributaries were different the pollution level according to the flow-rate ($m^3/sec$) and stream influence area($km^2$), and the difference of these was observed highly at Nam river. Specific contamination investigation of tributaries in Nam and Kumho river watershed was conducted from two to nine points of the fine parts of tributaries depending on the confluence sites and shapes. This result observed high at the Dalseocheon and Uriyeongcheon, respectively. Beside, the pollutant load contribution rate of Nakdong watershed was high about 10% at the Dalseocheon and Uiryeongcheon. This was due to the differences of the environments about the industrial complex, metropolis residence property, agricultural cultivation, livestock pen and the downstream of non-point source.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.3
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• pp.165-174
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• 2015

Non-point source pollution associated with suspended solids in stormwater has been known to often adversely affect surface water ecosystems. Various methods of treating stormwater in the basin area before the stormwater reaches the receiving body of water have been developed. However, these treatment methods tend to be costly to install and also to maintain. In this study, an economical way of removing TSS (total suspended solids) from stormwater runoff with a fabric filter system was developed. Polyester was chosen as a fabric-filter material, because it was found to be economical in cost and relatively resistant to various chemicals. An experimental device was developed and used to determine filtration rates through polyester fabric samples of a series of several pore-opening sizes ($20{\mu}m$ to $94{\mu}m$) under a series of water-heads (0.25 to 1 m). It was found that the filtration rate increased as the size of water head increased. It was also found that the smaller the pore size of the fiber filter was, the higher the TSS removal efficiency was. However, the TSS removal efficiency was not found to be much different among the filters with different sizes of pore opening due to the fact that most mass of TSS was associated with large particles.

• Korean Journal of Environmental Agriculture
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• v.20 no.3
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• pp.192-200
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• 2001

The event-based agricultural non-point source(AGNPS) pollution model was applied to estimate the loads of nitrogen and phosphorus in a stream draining small agricultural watersheds. Calibration and verification of the model were performed using observed data collected from rainfall events in the Imgo watersheds during 1997-1998. Parameter calibrations were made for the runoff curve number. The peak flow volumes in the watersheds were well reproduced by the modified model. Average deviation between observed and simulated values was 10%, and this match was confirmed by the coefficient of efficiency value of 0.97. The deviations tended to increase as the peak flows increased. The simulated total N concentrations in the stream water were fairly close to the measured values, and the coefficient of efficiency in the estimation was 0.93. However, there were relatively large variations between calculated and observed values of total P concentration, and the coefficient of efficiency in the estimation was 0.74. Any inaccuracies that arise in estimating runoff flow and nutrient loading can not be explained exactly and further adjustment and refinements may be needed for application of AGNPS in agricultural watersheds. With this restrictions in mind, it can be concluded that AGNPS can provide realistic estimates of nonpoint source nutrient yields.

• The Korean Journal of Malacology
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• v.32 no.2
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• pp.83-93
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• 2016

For the continuous stable production of oyster, estimation of food availability (F) was carried out in Goseong Bay, south of coast Korea. Primary productivity ranged from 0.07 to $0.44gC/m^2/day$ (average $0.25gC/m^2/day$), lowest in July and highest in January. The distribution of primary productivity at Goseong Bay showed the pattern of "high in the south and low in the north." Food availability (F) was $F{\leq}0$, indicating insufficient food supply, from August to November and F > 0 from January to April. Continuous insufficient food supply was observed at 18 oyster farms in the southern part of the bay and 4 in its northern part. Mortality at the oyster farms was 56% on the average, and around 58% of death occurred during November when food supply was insufficient. The optimal population of cultured oyster per unit flow area was calculated to be $110-115indiv./m^2$ (198-201 indiv./string). When the sea area was divided into 3 regions (A, B, C) according to carrying capacity, the carrying capacity of (A) regions was $52-53indiv./m^2$ (93-95 indiv./string), (B) regions was $142-144indiv./m^2$ (255-259 indiv./string), and (C) regions was $198-202indiv./m^2$ (356-363 indiv./string). In particular, (A) regions showed extremely low productivity. For continuous stable oyster farming at Goseong Bay, it is necessary to control point and non-point source pollution through continuous environmental monitoring and to adjust harvest according to the base carrying capacity during the season of high water temperature.