• KCID journal
• /
• v.13 no.2
• /
• pp.283-292
• /
• 2006

The characteristics of nonpoint source pollutant loads in upstream of Nakdong River were studied through analysis of pollutant loads of 10 sub-watersheds divided based on administrative district. The discharge and pollutant concentration of each sub-watershed were collected from Nakdong-River Water Research Institute and Daegu Regional Environmental office, respectively. Pollution items analysed in this study were BOD, T-N and T-P. The delivery loads of the nonpoint source pollutions of each sub-watershed were calculated after analysing the concentration of the pollution of each site. Several points were found from the results. Firstly, in general, city areas including Sangju, Andong showed higher degree of nonpoint pollution than country areas including Cheongsong, Yeongyang. The sub-watersheds located upstream side, such as Yeongju, Bonghwa, Necessarily show better water quality than the sub-watersheds located downstream side, such as Mungyeong, Uiseong. This result indicates that a given pollution condition within the watershed can be more sensitive than location factor to the level of water quality. Secondly, the delivery load and area of watershed were not necessarily correlated in the sense of water quality, while the discharge was shown to be highly correlated to the delively load of pollution. Lastly, sewage and waste caused from population and livestock, as well as landuse factor, were found to significantly contribute to the water pollution. Alternative solutions for controlling pollution source, therefore, should be provided to meet target levels of water quality in these regions.

• Journal of Wetlands Research
• /
• v.14 no.4
• /
• pp.607-628
• /
• 2012

The watershed of Gohyeon Stream was divided into the 10 sub-basins, and 19 sampling points were selected in their tributaries, which the characteristics of the water quality and pollution loads variance were investigated for during the rainy and dry seasons. The results of water quality analysis revealed that the upper watershed(T1~T8) of Gohyeon Stream had a feature of rural area, and its lower watershed(T9~T19) had a feature of the municipal area. The non-point pollution loads of the tributaries were estimated with 2,063, 601, 365, and 45 ton/yr of SS, COD, DIN, and DIP, respectively. The pollution loads of the parameters except DIP were generated about 60% during the rainy season, which suggested that a precipitation significantly influenced on the discharge of non-point source pollution. Meanwhile, the non-point pollution load of DIP was generated about 60% during the ordinary and dry seasons, which suggested that control of a phosphorus pollution source was significantly required during these seasons. Pearson's correlation analysis revealed that SS pollution source of the upper watershed was definitely different from that of the lower watershed, that is, the pollution load from the upper watershed was mainly caused by the discharge of SS due to soil erosion in the farmland and forest land during the rainy season, and that of the lower watershed by the discharge of sewage and municipal run-off.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2007.05a
• /
• pp.433-437
• /
• 2007

최근 환경부에서는 낙동강 유역의 오염총량관리제도의 시행에 따라 이제까지의 배출구 수질기준으로부터 총량수질기준을 통한 수질관리를 실시하고 있다. 오염총량관리를 실행하기 위해서는 주요지천 및 폐수처리장에서의 수질개선 및 비점오염원 관리가 선행되어야 하는데 이를 효율적으로 제어하기 위해서 낙동강 유역에 적합한 최적 수질해석 모델의 개발이 요구되는 상황이다. 수질모델의 가장 큰 목적은 유역으로부터 발생한 오염물이 하천으로 유입되었을 때 하천 수질 및 생태계의 수학적 표현을 통해 장래의 수질을 예측하고, 예측된 결과에 따라 합리적인 수질관리대책을 수립하는 것이다. 낙동강은 대표적인 수지상 하천망의 형태로서 댐 방류량 및 지류유입량은 본류 수계에 직접적인 영향을 미치며, 수질해석의 기본이 되는 수리계산에 매우 중요한 변수가 된다. 또한 대구, 구미, 왜관, 김천 등에서의 오염부하가 금호강, 남강 등의 주요 지류를 통하여 본류부로 유입되고 있으며, 하류부 칠서, 원동, 매리, 물금 등에서는 대량의 하천수를 취수하여 부산, 울산, 마산, 창원 지역 등의 생활 및 공업용수의 원수로 사용하고 있다. 다시 말해서 댐 방류량, 낙동강 하구언의 수위조절, 지류 유입량, 비점원 유입량 등 계산영역 경계에서의 비정상상태의 수리조건과 수질관리 계획에 의해 일률적으로 오염이 부하되는 정상상태의 수질조건이 공존하고 있는 실정이다. 본 연구에서는 낙동강 유역에 적합한 동적 수질모델을 개발하였다. 본 연구에서 개발된 수치모형은 갈수저수조건 및 불규칙한 하도단면을 반영하고, 동적 상태의 댐 방류량, 낙동강 하구언의 수위조절 영향, 지류 유입량 등 다양한 하천조건에서 발생하는 동적 흐름을 안정적으로 해석하여 낙동강 수질해석의 신뢰도를 향상시킴으로서 낙동강에 유입된 오염물질이 수계에 미치는 영향을 정확히 분석하고자 하였다. 동적수질해석에 의한 모의결과는 유량의 경우 상류부분은 모의치와 실측치가 잘 일치하지만, 중류 이후 지류의 유입이 많아지면서 지류의 변화를 정확히 입력하지 못해 모의치와 실측치의 차이가 발생한다. BOD의 경우는 수질이 양호한 상류지역은 모의치와 실측치가 잘 일치하지만, 오염원의 유입이 많은 중류지역부터는 실측치와 차이를 나타내다가 하류지역에서 다시 비교적 일치함을 알 수 있다. TN의 경우는 전반적으로 실측치보다 높게 모의되었고, TP는 전반적으로 실측치와 비교하여 잘 모의되었다. 본 연구에서 구축한 동적 수리해석모형 및 동적 수질해석모형은 낙동강 유역에 대해 유량 및 수질 등의 실제 하천의 경향에 비교적 잘 반영하므로 오염물총량규제에 따른 합리적인 하천 수질관리대책을 수립하는데 크게 기여할 수 있을 것으로 기대된다.

• Journal of Korea Water Resources Association
• /
• v.53 no.5
• /
• pp.369-381
• /
• 2020

In this paper, observed water quality, algal blooms and flow rates in the Yeongsan River and its boundaries including 8 tributaries and 2 wastewater treatment plants for two years of 2018-2019 were analyzed. It seems effects of non-point source load inputs from basin areas to the river may be significant though the field data availability was limited. The EFDC model was calibrated against data collected from 6 water level monitoring stations and 6 water quality monitoring stations, respectively, in the study area. Water quality improvement scenarios were developed assuming 50% and 75% reductions of major pollution sources including treatment plants and tributaries. The developed scenarios were applied to the EFDC model to estimate effects on algal bloom occurrences in the Seungchon weir and Juksan weir. Improvement of the effluent of Gwangju 1 WWTP by 75% did not show any effect on algal blooms for two weir locations. The major tributary affecting algal blooms in the Seungchon weir was the Hwangryong River. The Jisuk stream was found as the most important tributary for the Juksan weir followed by the effect of the Hwangryong River. Though it seems other scattered small nonpoint source load input to the Yeongsan river also seem to be important, it was not possible to reflect their effects appropriately due to field data availability.

• Korean Journal of Agricultural Science
• /
• v.26 no.2
• /
• pp.61-69
• /
• 1999

The water quality of river has been deteriorated mainly by both point source pollution and nonpoint source pollution from the watershed. Techniques to cut point source pollutants down to the level required have been developed. But, techniques of best management practices to catch the nonpoint source pollutions and to control the routine of pollutants were not successively developed. The quality of closed water system such as reservoir, lake and farm pond is irresistable to being polluted mainly by nonpoint source pollutions. In this study, the population, land use, runoff coefficient, amount of rainfall, and runoff discharge in the watershed were surveyed to investigate the characteristics of water quality such as BOD, COD, SS, T-N, and T-P. After studying the changes of water quality in the viewpoint of land use such as paddy land, residential area, upland, forest and meadow, load factors of nonpoint source pollutant were calculated in Bangdong reservoir watershed. Residential area was more severe than other land use as far as BOD, COD and SS concerned. T-N and T-P released from the paddy and upland were higher than other land use. The 45.9% of total load of nonpoint source pollution was occured during the rainy season.

• Journal of Korea Water Resources Association
• /
• v.32 no.4
• /
• pp.501-510
• /
• 1999

Stream and groundwater qualities of small agricultural watershed in Kangwon Probince, Korea were monitored 1 to 2 years, and the relationships between stream and groundwater qualities and seasonal water quality changes analyzed. Flooded paddy fields influenced groundwater level and quality during rice culture. The differences between groundwater levels during rice culture and non-culture spans were between 0.8 and 2.91 m. Seasonal changes of total nitrogen and nitrate nitrogen concentrations of stream and groundwater were very similar and groundwater quality was thought to have a profound impact on stream quality of the research watersheds. Suspended solids and BOD maintained the first degree stream water quality throughout the monitoring period except for a few and short flooding spans. The concentrations of total phosphorus and total bacteria of both waters showed wide variations and any seasonal trends were not observed. Long-term monitoring studies on small rural watersheds were recommended to understand the pattern of both stream and groundwater quality changes with respect to land use, season and cultural practice, and to apply the results to develop effective water quality management policies for large river and domestic water supply systems.

• Korean Journal of Ecology and Environment
• /
• v.39 no.4 s.118
• /
• pp.481-488
• /
• 2006

The field scale experiment was performed to examine the performance of the constructed wetland for nonpoint source (NPS) pollution loading reduction. Four sets (0.88 ha each) of wetland and pond system were used. After three growing seasons of the wetland construction, plant coverage increased to about 90% even without plantation from bare soil surfaces at the initial stage. During the start up period of constructed wetlands, lower water levels should be maintained to avoid flooding newly plants, if wetland plants are to start from germinating seeds. The average removal rate of $BOD_5$, TSS, T-N and T-P during the first two years was 5.6%, 46.6%, 45.7%, and 54.8%, respectively. The $BOD_5$ removal rate was low and it might be attributed to the low influent concentration. The early stage of wetland performance demonstrated the effectiveness of water quality improvement and was satisfactory for treating polluted stream waters. From the first-order analysis, T-P was virtually not temperature dependent, and $BOD_5$ and TSS were more temperature dependent than T-N. A pond-wetland system was more effective than a wetland-pond or a wetland alone system in water quality improvement, particularly to reduce T-P. Overall, the wetland system was found to be an adequate alternative for treating a polluted stream water with stable removal efficiency and recommended as a NPS control measures.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2017.05a
• /
• pp.89-89
• /
• 2017

유기농업은 저농약, 무농약, 자연농법과 함께 환경 친화적 농업으로 인식되어 세계적으로 유기농산물 생산량 및 재배면적이 급격하게 증가하고 있다. 국내 역시 안전한 먹거리 생산과 재배환경에서의 유해물질 관리방안 구축 등이 필요한 상황이다. 자가생산 유기농자재, 가축분을 이용한 축분 퇴비와 액비, 그리고 유박 등이 유기농업에 활용되고 있으나 사용 유기농자재의 양분가용화와 양분이용효율에 따른 비점오염원 형태로 토양 및 수질에 미치는 환경영향 등의 관측과 분석이 필요한 실정이다. 따라서 본 연구의 목적은 밭 포장에서의 유기농업 적용에 따른 유기농과 관행농에서의 대표적 비점오염원인 영양물질(T-N 및 T-P)에 대한 원단위를 평가하는데 있다. 시험포장은 전북 순장군 순창읍에 위치하고 있으며, 유기질비료시비 및 관행작물(고구마)의 3반복 1처리구(경사도 $6.6^{\circ}$)와 관행농관리 및 관행작물(고구마)의 1반복 1대조구(경사도 $6.8^{\circ}$)로 구성하였다. 현장에서 강우량과 유량을 실측하였으며, 강우 이벤트 시 T-N 및 T-P의 수질항목을 샘플링 후 분석하였다. 2016년 현재까지 총 6회의 강우 이벤트가 발생하였으며, 그 중 4회의 수질 샘플링을 실시하였다. 유출률은 평균 유기농에서 32%와 관행농에서 57%로 나타났다. 이는 토지피복 및 선행강우 등의 영향으로 다양한 분포를 보여주었다. 유기농 처리구에서 수질 부하량이 전체적으로 높게 나타났으며, T-N의 경우 4.4배와 T-P의 경우 1.8배로 나타났다. 이러한 경향은 유출수의 농도 영향보다 유출량의 영향이 큰 것으로 보인다. 유기농 처리구의 경우 제초제 등의 농작업이 제대로 이루어지지 않아 조도계수가 높았으며, 유기농 처리구에서 유출량이 31% 수준으로 상대적으로 낮게 나타났다. 본 연구의 경우 관행적으로 이루어지는 제초관리 형태를 벗어난 경우로 일반적인 결론 도출에는 한계가 있으나 유기농업 경작지에서 일반적으로 식생분포가 활발한 특성을 보여주고 있다. 향후 추가적인 모니터링 연구가 지속적으로 필요하며, 본 연구를 바탕으로 유기농업 최적관리방안 제시에 필요한 기초자료로 활용되기를 기대된다.

• Journal of Korea Water Resources Association
• /
• v.52 no.3
• /
• pp.207-217
• /
• 2019

This study aims at development and application of a facility that is capable of reducing pollution in water quality by reducing nonpoint source pollutants (NPSP). NPSP originated from the initial rainfall caused not only large catchment of urban area pass a river but also small watershed pass a stream. For this purpose, the performance tests carried out with the field models from the facility based on the preceding study. And the tests induced reduction efficiency of biochemical oxygen demand (BOD), chemical oxygen demand (COD), total nitrogen (T-N) and suspended solid (SS), respectively. The average reduction efficiency obtained by time interval, and the result showed an excellent reduction performance. As a result, the facility satisfied reduction efficiency of NPSP of the proposed standard by the National Institute of Environmental Research, and thus it can be used in practical applications.

• The Journal of the Korea Contents Association
• /
• v.16 no.1
• /
• pp.140-150
• /
• 2016

This study aims to investigate the effect of vegetation type, length of vegetative filter strip, and rainfall on trapping efficiency of the non-point source water pollution. Numerical experiments are carried out using VFSMOD-w. It is known from this study that the vegetation having the same value of revised Manning roughness coefficient shows the similar trapping efficiency in VFSMOD-w. When the length of vegetative filter strip increases twice, the trapping efficiency increases negligibly small under the same condition of rainfall. From this finding, it is also known that most of sediment are removed within a certain length of vegetative filter strips. It is concluded that the installation of vegetative filter strip is determined under the consideration of the rainfall characteristics, space of vegetation, and length of vegetative filter strip.