• Journal of Wetlands Research
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• v.20 no.4
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• pp.304-313
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• 2018

Agricultural land reclamation in Saemangeum tidal land project is mostly planned to be completed by 2020. Irrigation water for the land is required to be prepared by that time. However, water quality for the irrigation sources is barely meet the target concentration. This paper described the reduction effect of and policy consideration for best management practices (BMPs) which were fertilizer prescription by soil test (SO#1), mixed application of SO#1 and 3 (SO#2), drainage gate control (SO#3), time-release fertilizer application (SO#4), and control (CT). Reduction of paddy runoff was relatively higher in SO#3 (25%) and SO#1 (27%) while lower in SO#4 (9%) and SO#2 (7%) than that in CT. In addition, farmers promised to follow the BMP guidelines but they didn't because of the several problems caused for the BMPs implementation. Thus, it recommended developing an automated control of irrigation gate and paddy water depth and supporing farmers for NPS pollution control and irrigation water reduction.

• Journal of The Korean Society of Agricultural Engineers
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• v.62 no.5
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• pp.15-26
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• 2020

There are fifteen non-point pollution management areas in Korea and three of them (Doam lake, Daegi district and Golji-cheon) are located in the upstream of the Namhan river watershed. Many efforts to reduce non-point sources (NPS) pollution have been conducted, however, water quality pollution in the watershed is still serious. To solve these problems, it is a priority to grasp water quality using statistical techniques. In this study, a trend analysis was conducted to evaluate the effect of NPS management in the watershed. The long-term trends from 1996 to 2018 of water quality properties were analyzed using data collected from the water environment information system. Seventeen monitoring stations were selected along the main stream in Namhan river basin. Monthly water quality properties (BOD, COD, TN, TP, TN/TP ratio, Conductivity, SS and Chlorophyll-a) were collected and analyzed by Mann-Kendall test and LOWESS. The results showed that the Conductivity tended to increase in all regions and was the highest level in Jijangcheon. Organic pollution such as BOD and COD tended to increase in the Jungseon area. SS did not show a large tendency, but it showed high concentration in the Doam watershed. In all regions, 40% of water quality properties showed a tendency to 'UP', 15% of water quality properties tended to 'DOWN', and 46% indicated no tendency. In order to determine the cause of this, additional research and measures for improvement are necessary. This study will be used for the establishment of water quality policy in the future.

• Journal of The Korean Society of Agricultural Engineers
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• v.56 no.3
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• pp.47-53
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• 2014

We investigated the effect of straw mat cover and soil amendments on the reduction of runoff, non-point source pollution load and yield of a Chinese cabbage from alpine fields. Two plots on sandy loam soil were prepared. Experimental treatments were control and rice straw mat cover (3,300 kg/ha)+Polyacrylamide (PAM) (5 kg/ha)+Gypsum (1 ton/ha) (SPG). A variety of Chinese cabbage was cultivated and runoff was monitored during a growing season in 2012. Monitoring was conducted to seven times. Runoff rate of SPG plot was lower than those of control plot. The reduction rate of runoff from SPG plot was 29.4 % compared to control plot. The reduction rate of suspended solids (SS), total nitrogen (TN) and total phosphorus (TP) load of SPG plot was 86.5 %, 34.7 % and 39.1 %, respectively. Yield of a Chinese cabbage from SPG plot (39,646 kg/ha) was greater than that of control plots (28,482 kg/ha). It was concluded that the use of SPG on soil surface could not only reduce the NPS pollution loads in receiving waters but also help increase the crop yield.

• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.3
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• pp.31-38
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• 2010

Various fundamental and practical theories and technologies are needed for the development of Best Management Practices (BMPs) to manage the problems. The objectives of this paper was to investigate the effect of fertilizer and Non-point suource (NPS) pollution discharges from the field. The effect of fertilizer application was measured with respect to 10 % and 20 % slopes, respectively, using artificial rainfall simulator. The effect of fertilizer application on runoff was not significant because the effect of slope and rainfall intensity were overwhelmed. Runoff from 20 % plots was 21 % larger than that from 10 % plots. While groundwater discharge from 10 % plots was about 70 % larger than that from 20 % plots. It was concluded that runoff and groundwater discharge were largely affected by slope. T-N concentration in groundwater was much higher than that in runoff for both 10 % and 20 % plots. While T-P concentration in groundwater was lower than that in runoff. It explained that T-N moved well through soil pores without adsorption and other chemical reactions but T-P was well adsorbed on the surface of soil particles.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.5
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• pp.440-448
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• 2016

Nonpoint sources of pollution (NPS) is defined as diffuse discharges of pollutants (e.g., nutrient, pesticide, sediment, and enteric microorganism) throughout the natural environment and they are associated with a variety of farming practices. Previous studies found that water soluble anionic polyacrylamide (PAM) is one of the highly effective measures for enhancing infiltration, reducing runoff, preventing erosion, controlling nonpoint source of pollutants, and eventually protecting soil and water environment. Potential benefits of PAM treatment in agricultural soil and water environments have been revealed by many research and they include low cost, easy and quick application, and suitability for use with other Best Management Practices (BMPs) for NPS control. This study reviews the various applications of PAM and discusses its further potentials in agricultural environment.

• Journal of Wetlands Research
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• v.13 no.2
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• pp.199-208
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• 2011

Scarcity of water worldwide, increasing greenhouse gas emissions, increased energy consumption due to the Earth is threatened. Existing in the process of urban planning and development of forests, rivers and other natural ecosystems have been destroyed and that there was increased impervious pavement. Impervious pavement increase water circulation system to destroy the natural and urban water retention, infiltration and decreased evaporation. Nonpoint source pollution(NPS) occurs when rainfall impervious pavement and appeal directly to the river water inflow is adversely impacts of the situation. In this study, rainfall occurs impervious pavement NPS pollution reduction and temperature increase due to the increase in urban areas, and to solve heat island phenomenon is to develop small HSSF constructed wetland technology. The small HSSF constructed wetland sedimentation, filtration, adsorption, absorption by vegetation, including such mechanisms. Techniques for verification of the pilot-scale test was conducted. In the future domestic urban heat island phenomenon and restore the natural water cycle for the facilities will be used as a basis to develop.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.9
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• pp.643-653
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• 2013

In this study, trend analysis was performed by various runoff analysis method of Non-point Pollution Source(NPS) at the impervious area. The characteristics of rainfall at impervious area appeared to be influenced by rainfall strength and it appeared that first flush phenomenon occurs often if rainfall strength acts largely. It is judged that the measure is required to be prepared against that now that concentration difference of non-point pollution source appeared to be big by precedent number of days of no rainfall. As the result of calculating Decrease Rate (DR) by first flush of non-point pollution source, it is judged that it is important to prepare the measure against the pollutants about initial rain and it is necessary to calculate the capacity of non-point pollution source processing facilities regarding that now that the non-point pollution source integrated at impervious area showed the characteristics that are flowed out in high concentration by initial rain in case of non-rainfall considering the characteristics of non-point pollution source at impervious area. When taking 50% of non-point pollution source as the standard for decrease rate that was evaluated previously, it appeared as 15~60 min in case of TSS and it appeared as 30~90 min in case of organic compound, but the characteristic whose decrease rate is below 50% also appeared even till rainfall-runoff ends. Based on that, it is judged that it could be used as the reference when designing the structural BMPs facilities later.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.6
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• pp.1006-1013
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• 2014

Wastewater organic compounds, that is, nonylphenolic compounds (NPs) and fecal sterols, were measured in surface sediments from Busan Suyeong Estuary, where two wastewater treatment plants (WWTPs) are located, to assess contamination from municipal effluents. The NPs analyzed were nonylphenol, and nonylphenol mono- and di-ethoxylates, all synthetic endocrine disruptors. The fecal sterols analyzed were coprostanol (COP), cholestanol, and epicoprostanol. Concentrations of NPs in the sediments ranged from 146 to 3,723 ng/g, and those of COP ranged from 366 to 13,018 ng/g. Their detection in all of the sediments analyzed indicates widespread pollution by municipal effluents. The highest concentrations of NPs and COP were detected at stations close to outfalls of WWTPs. Their levels in sediments are categorized in the higher range of those previously reported in Korean coastal areas. Moreover, in comparison with screening values of NPs in the Netherlands, Norway, and Canada, more than 50% of the sampling stations exceeded the guidelines. This indicates that the estuary may be adversely influenced by municipal effluents.

• Journal of The Korean Society of Agricultural Engineers
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• v.53 no.5
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• pp.35-42
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• 2011

This study is to check the applicability of SWAT-APEX (Soil and Water Assessment Tool-Agricultural Policy / Environmental eXtender) model as combined watershed and field models by applying the APEX to paddies in a watershed (465.1 $km^2$) including Yedang reservoir. Firstly, the SWAT were calibrated with 3 years (2000~2002) daily streamflow and monthly water quality (T-N and T-P) data, and validated for another 3 years (2003~2005) data. The average Nash-Sutcliffe model efficiency (ME) of streamflow during validation was 0.73, and the coefficient of determination ($R^2$) of T-N and T-P were 0.77 and 0.73 respectively. Next, running the SWAT-APEX model with the SWAT calibrated parameters for paddies, the $R^2$ of T-N and T-P were 0.80 and 0.76 respectively. The results showed that SWAT-APEX model was more correctly predicted for T-N and T-P loads than SWAT model. The difference results between watershed and field models was predicted to have substantial impact on NPS loads, especially on T-N and T-P loads. Therefore, to improve negative NPS load simulations should be considered the model characteristics as simulating mechanism to properly select the NPS model for agricultural watershed.

• Fisheries and Aquatic Sciences
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• v.13 no.3
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• pp.236-243
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• 2010

Fecal sterols, nonylphenolic compounds (NPs), and polycyclic aromatic hydrocarbons (PAHs) were determined in surface water from Masan Bay and its adjacent rivers in February 2005. Concentrations of coporstanol (Cop), an indicator of fecal pollution, in surface water ranged from <10 to 13,853 ng/L, and concentrations of nonylphenol, the most toxic of the NPs, ranged from 10.2 to 481 ng/L, and concentrations of PAHs ranged from 8.61 to 223 ng/L. The concentrations of the compounds measured in this study were lower than or comparable to those at other locations in Korea and other countries. The contamination of Cop and PAHs in surface water was associated with the discharge from rivers passing through cities and/or industrial complexes. The NP contamination was associated with wastewater treatment plant (WWTP) effluents through outfalls as well as riverine discharge. Compared to ecotoxicological values, the concentrations of NPs from rivers, the mouths of rivers, and WWTP outfall areas exceeded guidelines, suggesting that hot spot areas may pose a potential risk to sensitive species.