• Journal of Environmental Impact Assessment
• /
• v.23 no.1
• /
• pp.19-27
• /
• 2014

The purpose of this study is to provide a base line data to improve the water quality in the Yeongsan River basin. As the major factor that affects the water quality of Yeongsan River is nonpoint pollution source, in order to find a resolve to improve the quality, a study was conducted to identify the correlation between the stream water quality and that of the land use. The study showed that the concentration of the contents in the water from the agricultural land environment was found to be higher as oppose to that found in the content of the water from the forest land. As a result, it can be deducted that agricultural land deteriorates water quality whereas that of the forest land is of much better quality. Therefore, it is highly recommended to take advanced improved care of agricultural land close to a water source to improve the quality of Yeongsan River basin.

• Korean Journal of Ecology and Environment
• /
• v.45 no.1
• /
• pp.62-71
• /
• 2012

Lake Doam watershed was surveyed to evaluate non-point source discharge characteristics and discharge load including several water quality parameters in Song Stream from July 2009 to July 2011. Concentrations of water pollutants were high during the rainfall period, especially, SS, TP and COD showed increasing tendencies toward cumulative water discharge but TN did not show much difference. SS, TP and COD had an initial flush effect of over 50 mm rainfall event but there was no clear tendency for rainfalls below that level. Event mean concentration (EMC) regarding the rainy and dry period showed large differences. Especially rainy season EMC (SS, TP, COD) demonstrated an increasingly high tendency. EMCs of COD, SS, TN and TP measured for twelve rain events were as high as 26.1, 866.0, 4.68 and 0.605 mg $L^{-1}$, respectively. COD, SS, TN and TP loadings from the highland agricultural region of the Song Stream watershed were 34,263, 1,250,254, 2,673 and 933 kg $yr^{-1}\;km^{-2}$, respectively, which were relatively higher than the results of other stream systems. Therefore, it is strongly recommended that long-term monitoring and non-point pollution reduction programs for the highland agricultural area to continue. Furthermore, this non-point source pollution loading research acquired from the highland agricultural area could be the base for reassessment.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2002.10a
• /
• pp.453-456
• /
• 2002

In this study, the effect of DEM resolution (15m, 30m, 50m, 70m, 100m, 200m, 300m) on the hydrological simulation was examined using BASINS (Better Assessment Science Integrating point and Nonpoint Source) for Heukcheon watershed (303.3km2) data from 1998 to 1999. Generally, as the cell size of DEM increased, topographical changes were observed as the original range of elevation decreased. The processing time of watershed delineation and river network needed more time and effort on smaller cell size of DEM. The larger DEM demonstrated had some errors in the junction of river network which might effects on the simulation of water quantity and quality. The area weighted average watershed slope became lower but the length weighted average channel slope became higher as the DEM size increased. DEM resolution affected substantially on the topographical parameter but less on the hydrological simulation. Considering processing time and accuracy on hydrological simulation DEM mesh size of 100m is recommended for this watershed.

• Korean Journal of Environmental Agriculture
• /
• v.33 no.2
• /
• pp.144-147
• /
• 2014

BACKGROUND: It is essential to prioritize the exact and clear understanding of agricultural nonpoint source pollution (NPS) controls. The realistic policies and systems should also be developed based on this understanding. Therefore, this study aimed to present agricultural Best Management Practices (BMPs) applicable for the fields based on the Delphi survey result. METHODS AND RESULTS: This study deduced the evaluation items to assess each BMP for agricultural NPS control and conducted the surveying using the Delphi method based on agricultural BMP experts. In addition, its on-the-spot application were evaluated. Considering its importance, technical, social and economic proprieties showed that political support was ranked first and followed by cost investment, labor investment, reduction effect and resident participation. The survey findings by agricultural BMP experts showed the good performance of on-the-spot application can be achieved from fertilization by soil testing, residue and green manure application and contour plowing which are applicable within a field. Agricultural BMPs, highly applicable for the fields, were the countermeasures that farmers who are the principal bodies of agricultural NPS control could be participated directly. CONCLUSION: The active participation of farmers is essential for effective control of agricultural NPS. It is necessary to establish various incentive systems.

• Journal of Applied Biological Chemistry
• /
• v.57 no.1
• /
• pp.95-101
• /
• 2014

Nonpoint pollution sources from agricultural activities are a major cause of water quality impairment. A nutrient management program utilizes farm practices that maintain efficient crop production systems and control agricultural nonpoint pollution sources. The objectives of present study were to identify appropriate best management practices (BMPs) according to changes of cropping system of main upland crop for reducing AGNPs loadings and to simulate the effects of the application of the several BMPs scenarios in Saemangeum watershed. The selected BMP scenarios were: 1) to convert naked barley and hulled barley to hairy vetch or chinese milk vetch, 2) to convert red pepper to soybean crop, and 3) to combine two scenarios, converting naked barley and hulled barley to hairy vetch or chinese milk vetch + converting red pepper to soybean crop. As a result of BMPs application, the crop requirement of nitrogen and phosphorus for upland crop reduced nitrogen by 41% and phosphorus by 47% in scenario 1, whereas scenario 2 reduced nitrogen by 30% and phosphorus by 23%. Overall, scenario 3 reduced nitrogen by 72% and phosphorus by 70% in agricultural non-point pollution sources associated with chemical fertilizer and livestock manure in Saemangeum watershed.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.23 no.6
• /
• pp.137-149
• /
• 2020

This study was carried out to analyze the monthly runoff concentration on non rainfall days in order to prepare basic data to compare the runoff concentration on rainfall days in 7 forest watersheds in the Republic of Korea. Forest stream water has been collected through 15 times of sampling in each watershed and analyzed based on the changes in concentration of Biochemical Oxygen Demand(BOD), Chemical Oxygen Demand(COD), Total Organic Carbon(TOC), Total Nitrogen(TN), and Total Phosphorus(TP). The average concentration was 0.8 mg/L for BOD, 1.4 mg/L for COD, 0.8 mg/L for TOC, 1.85 mg/L for TN and 0.002 mg/L for TP during non rainfall days. Coniferous forested watersheds showed higher value of TN and TP concentration. Concentrations of BOD and TP in early March (p<0.01) were affected by melt water flow input in spring season. Significant differences (p<0.01) in concentrations were observed in BOD and TOC, indicating seasonal rainfall and vegetation growth impacts on forest stream quality. Concentration of TN and TP showed significant positive correlation, and weak negative correlation was found in the concentration of BOD and TOC. It is expected that result of forest stream water on non rainfall days could be basic information in managing non-point source from forest watersheds.

• Journal of Korean Society on Water Environment
• /
• v.31 no.2
• /
• pp.166-180
• /
• 2015

Pollutant in watersheds comes from two major sources which are NPS (nonpoint source pollution) and PS (point source pollution). Most of the pollutant can be treated by wastewater treatment plants. However, wastewater treatment plants may not be an appropriate practice to improve water quality for the watersheds with large portion of NPS pollutant and NPS pollution from direct runoff and baseflow has different characteristics. Therefore the practices to improve water quality need to be comprehensive for pollutants by both direct runoff and baseflow. Riparian buffer, one of practices to manage pollutant in watershed, has been applied to reduce pollutant not only from direct runoff but also baseflow. In this study, the scenarios for pollutant reduction by wastewater treat plants and the nitrogen reduction by riparian buffer were simulated using SWAT-REMM to suggest an effective plan for pollutant reduction from baseflow. Riparian buffer provided nitrogen reduction of 0.2~75.0% in YbB watershed and 38.0~47.0% in GbA watershed. The result indicates that riparian buffer is effective to reduce the pollutant especially from baseflow, and it suggested as suitable for the a watershed which WWTP discharge is not capable to reduce enough pollutant.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.54 no.1
• /
• pp.55-62
• /
• 2012

This study is to assess the reduction of nonpoint source pollution by applying Best Management Practice (BMP) in Chungju-dam watershed (6,585.1 $km^2$) using Soil and Water Assessment Tool (SWAT). The model was calibrated using 3 years (1998-2000) daily streamflow at 3 locations and monthly water quality of sediment (SS), total nitrogen (T-N) and total phosphorus (T-P) data at 2 locations and validated for another 3 years (2001-2003) data. The 5 BMPs of streambank stabilization, porous gully plugs, recharge structures, terrace, and contour farming were applied to stream and area with the specific criteria of previous researches. Through the parameter sensitivity analysis, the farming practice P-factor and Manning's roughness of stream were sensitive. Overall, the NPS reduction effect was high for streambank stabilization, terrace, and contour farming. At the watershed outlet, the SS, T-P, and T-N were reduced by 64.4 %, 62.8 % and 17.6 % respectively.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.9 no.4
• /
• pp.129-134
• /
• 2009

As a result of improved wastewater treatment facilities, the point source pollution emitted from human and municipal wastes is greatly decreasing. Conversely, the non-point source (NPS) pollution emanated from city streets, rural homes, suburban development, animal feedlot, croplands, and forestry is rapidly increasing. Practically, the main concern of the government is to control NPS pollutants by means of establishing a long term plan in order to protect the aqua-ecosystem. Studies have been conducted to assess the intensity of NPS from various landuses. In Korea, the data on NPS pollutant loadings are limited to few and broadly categorized landuses unlike in USA wherein specific landuses are available. This research aims to characterize the wash-off characteristics of NPS pollutants from forest landuse. Two sites were monitored during 15 storm events from 04/2008 to 10/2008. Mean $BOD_5$ EMCs are 1.13 mg/L and 0.91 mg/L for the two sites, respectively. The results of this research will be a helpful contribution for the assessment of total NPS pollutant loadings.

• Journal of Wetlands Research
• /
• v.17 no.3
• /
• pp.303-310
• /
• 2015

Recently the water quality management policy gives priority to management the point source. Point pollution sources have definite emission points and are discharged to one point through a pipe. But Nonpoint pollution source (NPS) has uncertain pathway, pollutant load and runoff characteristics unlike point pollution sources, making them difficult to manage. Thus, the Korea government plans to develop and equip facilities that help reduce NPS so as to manage them more easily. But removal efficiency of Best Management Practice (BMPs) is in influenced by rainfall, hydrologic condition like natural phenomenon, so factors of removal efficiency are difficult. Thus there is a need for multilateral research about many factors that affect removal efficiency for removal facility design of proper non-point pollution. In this research, mapping, vegetation coverage and retention time were investigated in the case of factors that affect removal efficiency in grassed swale, a nature-type non-point removal facility. Grassed swale obtained changed of coverage using Braun-Blanquet within swale and retention time was obtained from point that rainfall effluent enters into swale to the time that first outflow starts. Besides, correlation analysis was obtained using pearson correlation analysis method. As a result, it was shown that removal efficiency increases as retention time is longer in grassed swale and that retention time increases as vegetation coverage is higher.