• Korean Journal of Remote Sensing
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• v.37 no.3
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• pp.367-378
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• 2021

Field compost is a representative non-point pollution source for livestock. If the field compost flows into the water system due to rainfall, nutrients such as phosphorus and nitrogen contained in the field compost can adversely affect the water quality of the river. In this paper, we propose a method for detecting field compost using unmanned aerial vehicle images and deep learning-based semantic segmentation. Based on 39 ortho images acquired in the study area, about 30,000 data were obtained through data augmentation. Then, the accuracy was evaluated by applying the semantic segmentation algorithm developed based on U-net and the filtering technique of Open CV. As a result of the accuracy evaluation, the pixel accuracy was 99.97%, the precision was 83.80%, the recall rate was 60.95%, and the F1-Score was 70.57%. The low recall compared to precision is due to the underestimation of compost pixels when there is a small proportion of compost pixels at the edges of the image. After, It seems that accuracy can be improved by combining additional data sets with additional bands other than the RGB band.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.282-282
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• 2021

강우시 농경지와 축산시설로부터 유출되는 비점오염물질은 하류 수계의 수질과 수생태계에 악영향을 미친다. 이에 따라 환경부에서는 비점오염원관리지역을 지정하고 다양한 비점오염 저감 대책을 시행하고 있다. 본 연구에서는 비점오염원관리지역으로 지정된 안동댐 하류 중 송야천 유역을 대상으로 강우유출수 모니터링을 수행하였으며, 모니터링 결과를 바탕으로 강우시 비점오염물질 유출 특성을 분석하였다. 모니터링 기간은 2020년 6월부터 11월까지 총 5회의 강우사상에 대하여 상·하류와 유입하천을 포함한 총 8개의 모니터링 지점을 대상으로 강우사상별 유량가중평균농도(Event Mean Concentration, EMC), 오염부하, 단위면적당 오염부하를 산정하였으며, 오염원 그룹별 비점배출부하를 산정하여 오염 기여도를 분석하였다. 강우유출수 조사결과를 이용한 EMC 농도 산정 결과 유입하천인 오산천 지점이 SS와 TOC 항목을 제외한 모든 수질항목의 EMC 농도가 가장 큰 것으로 나타났다. 단위면적당 오염부하를 산정하여 비교 분석한 결과 T-P 항목의 단위면적당 오염부하는 물한천 지점(0.69 kg/ha)과 오산천 지점(0.69 kg/ha)이 크게 나타났다. 결과와 같이 오산천 지점과 물한천 지점이 오염정도가 큰 것으로 나타났으며, 이에 따른 상류 오염원 현장 정밀조사를 수행하였다. 조사 결과 강우발생시 상류에 위치한 농경지와 축사에서 발생하는 오염원이 하천으로 유입되고 있었으며, 여러 축사에서 배출되고 있는 유입수를 채취하여 분석한 결과 T-P 농도가 평균 0.935 mg/L로 높게 나타났다. 전국오염원조사자료(국립환경과학원, 2017) 내용을 참조하여 송야천 유역의 오염원 그룹별 비점배출부하를 산정해 오염 기여도를 분석한 결과, T-P 항목의 경우 축산계와 토지계의 비점배출부하가 전체 비점배출부하의 약 63%와 37%를 차지해 비점배출부하 기여도가 큰 것으로 나타났다. 이와 같이 송야천 유역의 경우 강우시 농경지와 축산시설에서 배출되는 오염물질이 하천 수질오염에 상당한 기여를 하고 있는 것으로 보여지며, 비점오염원 발생에 대한 대책 마련이 필요할 것으로 사료된다. 본 연구 결과는 송야천 유역의 비점오염 저감 대책 수립을 위한 기초자료로 활용할 수 있을 것으로 판단된다.

• Journal of Environmental Policy
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• v.10 no.1
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• pp.49-70
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• 2011

The numerous efforts have been made in understanding generation and transportation mechanism of nonpoint source pollutants from agricultural areas. Also, the water quality degradation has been exacerbated over the years in many parts of Korea as well as other countries. Nonpoint source pollutants are transported into waterbodies with direct runoff and baseflow. It has been generally thought that groundwater quality is not that severe compared with surface water quality. However its impacts on groundwater in the vicinity of stream quality is not negligible in agricultural areas. The SWAT model has been widely used in hydrology and water quality studies worldwide because of its flexibilities and accuracies. The spatial property of each HRU, which is the basic computational element, is not presented. Thus, the SWAT HRU mapping module was developed in this study and was applied to the study watershed to evaluate recharge rate and $NO_3-N$ loads in groundwater. The $NO_3-N$ loads in groundwater on agricultural fields were higher than on forests because of commercial fertilizers and manure applied in agricultural fields. The $NO_3-N$ loads were different among various crops because of differences in crop nutrient uptake, amount of fertilizer applied, soil properties in the field. As shown in this study, the SWAT HRU mapping module can be efficiently used to evaluate the pollutant contribution via baseflow in agricultural watershed.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.10
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• pp.684-693
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• 2012

The stormwater runoff from the increasing paved roads and vehicles resulted in the increase in the pollutants load to adjacent water bodies. The granular media filtration facilities are the most widely adopted to minimize the non-point source pollution from motorways. It is essential to consider the severe variation of hydraulic condition, suspended solid (SS) characteristics, and the medium characteristics for stormwater management filter. In this study, different types of media, including sand, were tested and the performance of downflow sand filters was investigated under various linear velocity and influent solid particle size. Results showed that the best medium is the coarse sand with large grain size, which showed the specific SS removal before clogging of more than $8.498kg/m^2$, the SS removal of higher than 95%, and minimum head loss. Linear velocity did not affect the total solid removal, while the performance was improved when fine solid was introduced. It is suggested that the life of a downflow sand filter bed can be extended by deep bed filtration when influent particles are fine. However, the captured particles can be washed out after a long period of operation.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.8
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• pp.478-488
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• 2017

Stormwater filtration is widely used for the urban runoff treatment. However, intensive maintenance and lack of information about the performance have resulted in an increased need of proper evaluation. In this study, the performance of an upflow stormwater runoff filtration system, consisting of a supporting unit and a filtration unit filled with a ceramic media, was investigated. The maximum head loss increase was about 3 cm under the suspended solid (SS) load of $30kg/m^2$ and the SS removal was more than 96%, when the filtration velocity was 20-40 m/h. The head loss and the porosity of the media can successfully be described by a power model. It was confirmed that the a significant amount of SS can effectively be removed at supporting unit, minimizing SS load to the filter media bed. Several backwashing strategies have been tested to establish the optimum condition. It was found that the stagnant water discharge is important to minimize the SS release immediately after backwashing. Also, the filter bed loaded with $400-450kg/m^2$ SS can almost completely be washed to reduce the head loss to the that of empty bed. The results in this study indicate that the upflow ceramic media filter is an excellent alternative to stormwater treatment, with high SS removal and long lifespan.

• Journal of Wetlands Research
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• v.19 no.1
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• pp.80-89
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• 2017

Researches about NPS(Non-point Pollution Source) reduction have been widely carried out in recent years. A pilot channel-type constructed wetland (wet swale) was constructed in Rongyin area to treat stormwater generated from a green house agro-land of 22.7 ha. From 2006 to 2008, monitoring was conducted to evaluate its performance on the removal effect for organic pollutants as well as nutrients. Totally, sampling trips of 17 rainfall events were made and they covered most types of storm events in Korea. The channel-type constructed wetland have average removal efficiencies of 78.3~92.0%, 56.4~66.1%, 28.2~45.5% and 50.6~66.4% for SS, COD, TN and TP, respectively. According to four methods for estimating the removal efficiency, the average efficiencies of TSS, COD, TN and TP are 86.0%, 60.1%, 30.1% and 53.5%, respectively. From 2006 to 2008, annual efficiency improved due to infiltration potential increase. It was found that most of the pollutants removed in this channel type of wetland was particulate solids bound pollutants, which is assumed fact that it lacks of physico-chemical treatment conditions which are commonly observed in the retention type of constructed wetlands.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.12
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• pp.655-663
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• 2017

It is difficult to manage hotspot area and to establish the reduction plan considering with spatial-distribution on Korea TMDLs (Total Maximun Daily Loads) system. To solve this problems, methods of Load Duration Curve (LDC) using long-term flow and water quality data, and spatial-analysis were applied on present TMDLs. Jinwi A watershed which is enforced TMDLs plan were selected to study area. Results of application of suggested methods in this study to Jinwi watershed, Hwangguji tributary was selected to hotspot area and Jinwi tributary was exclued. Also, middle area of Hwangguji tributary was needed a reduction plan for the protection of non-point source pollution. In downstream area, livestock manure should be managed additionally. The new methods suggested in this study were useful to increase healthiness for total watershed.

• Journal of the Korean Institute of Landscape Architecture
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• v.45 no.6
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• pp.1-9
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• 2017

This study investigates the environmental factors of endemic species in Korea in order to understand their ecological characteristics, and to investigate the target species of their natural habitats to find similar sites. The purpose is to restore and follow suitable growth methods for the appropriate highway facility of target species to establish a management system via monitoring. This study endeavors to restore the target species near highway facilities on the basis of monitoring data and restore sites have similar natural characteristics of the target species. After restoring the target species, a restoration strategy and management plan will be established for breeding and continuation. The restoration strategy and management plan of the target species is divided into breeding, restoring, maintaining and monitoring plans. Specially management plans include several divisions such as soil, water, non-point pollution source reduction and naturalized plants. The results of this study can be used as reference materials for the restoration of endemic Korean plants in the future of highway routes, and for systematic management measures in habitats.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.6
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• pp.451-459
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• 2014

The development and reduction scheme under implementation plan of TMDLs were performed in the Jinwi watershed including 8 cities (Gunpo, Yongin, Suwon, Anseong, Osan, Uiwang, Pyeongtaek and Hwaseong) since 2012. Progress of the annual development schemes was faster than the reduction schemes in most of the cities during the planning period. Main load reduction methods included establishment and enlargement of sewage treatment plants, resources of livestock excretions, and introduction of best management practices of non-point source pollution. Especially, reduction load using recycling and composting of livestock excretions comprised 34.1% of all reduction load. It is necessary to implement methodical development and reduction scheme for making of successful performance of TMDLs and water quality improvement in the Jinwi watershed.

• Journal of Wetlands Research
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• v.24 no.1
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• pp.59-67
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• 2022

The interest in LID facilities is increasing worldwide for recovery of natural water cycle system to destroy by urbanization. However, problems are raised when installation of LID because comprehensive analysis about design capacity adequacy of LID facilities was not conducted completely. In this research, removal efficiency and design volume adequacy of LID facilities were analyzed based on rainfall monitoring data in four LID facilities(Vegetated Swale, Vegetative Filter Strip, Bio-Retention and Permeable Pavement). As a result, group of LID facility designed on WQV was shown higher flow(37%) and pollutants(TSS, BOD, TN and TP) removal efficiencies(20 ~ 37%) than group of LID facility designed on WQF. SA/CA graph was drawn for evaluation of design volume adequacy based on rainfall monitoring data. In this SA/CA graph, coefficient of determination show over 0.5 in all parameter, especially, Flow and TP were show over 0.95. And, 'SA/CA & L/CA' graph considering difference of structure mechanism in LID facility suggested in this research was confirmed that improved coefficient of determination in flow, TSS and TP than SA/CA graph. According to this research results, feasibility of applying 'SA/CA & L/CA' graph for evaluation of design volume adequacy in LID facility, and it is necessary to follow up research for generalization and normalization.