• 한국농공학회논문집
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• 제49권2호
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• pp.99-108
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• 2007

The purpose of this study was to investigate characteristics of concentrations of pollutants such as TN (Total Nitrogen), TP (Total Phosphorus) and COD (Chemical Oxygen Demand) in outflow from a nonpoint source dominated watershed ($6.7km^2$). Regular flow measurement and water sampling were taken at five-day intervals during two years (February 2002 to January 2004) in the Ingyeong River, a tributary of the Han River. The mean concentrations of pollutants during rainy days were significantly (p<0.05) higher than those during dry days. For dry days, the flow-weighted mean concentration (0.06 mg/L) of TP during paddy irrigation periods were higher than that (0.02 mg/L) during non-irrigation periods. The seasonal mean concentration of TN was highest in spring likely due to nitrogen fertilization, but those of TP and COD were highest in summer due to particulate phosphorus and sediment-associated organic matter caused by increased discharge. The pollutant concentrations significantly increased with discharge, suggesting that the measures to reduce the increase in the concentrations during storms are needed to control nonpoint source pollution.

• 한국농공학회지
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• 제44권5호
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• pp.127-135
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• 2002

Water quality samples were taken for every two hours whenever runoff occurred by rainfall to investigate concentration variations of T-N, T-P and SS during runoff process from a paddy field. The difference between the highest concentration in a runoff event and flow weighted mean concentration for T-N, T-P, SS placed between 3.07∼40.16%, 11.44∼60.80%, and 15.11∼64.5%, respectively. The difference between the lowest concentration in event and event mean concentration for T-N, T-P, SS ranged between -7.24∼-31.84%, -11.59∼-47.86%, and -5.21∼-36.20%, respectively. The relationship between runoff and mass load was derived for each storm event using observed data. The relationship between runoff and mass load showed linear relationship regardless of water quality constituents and rainfall amount. The results suggested that relationship between T-N and T-P loads and runoff should be prepared separately in considering of fertilization effect and seasonal conditions. The relationship between SS and runoff should be made to reflect seasonal conditions and tillage effect.

• 한국농공학회논문집
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• 제49권6호
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• pp.3-9
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• 2007

Stream flow and water quality were measured and analyzed with respect to flow-weighted mean concentrations (FWMCs) of 21 rainfall events from a forested watershed (Forest Research Watershed: FRW) and two mixed watersheds of agriculture and forest (YuPo-Ri Watershed: YPW and WolGog-ri Watershed: WGW) located in the middle of the North Han River basin. The monitoring of each watershed was one year and conducted between 2004 and 2006. YPW showed more intensive agricultural practices than WGW where traditional practices were common. The average of the 21 FWMCs were in the order of YPF>WGW>FRW and were significantly different from each other at the level of 0.05. It was shown that the land use with intensive agricultural practices produced and discharged more NPS pollutants than that with traditional practices and forest. Specially, SS concentrations from the mixed watersheds were significantly higher than those from FRW. Influencing factors on runoff were analyzed rainfall and watershed area. And rainfall intensity was greater impact on runoff than daily rainfall. Measured water quality indices were shown positive correlations among them in general. However, no significant correlation was shown between COD and nutrients(T-N and T-P).

• 한국물환경학회지
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• 제28권4호
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• pp.523-530
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• 2012

Runoff, NPS pollution load and flow-weighted mean concentration (FWMC) occurred by snowmelt and rainfall runoff were compared by a variance analysis. Snowmelt runoff ranged between 1,449 and $19,921m^3$. The peak snowmelt runoff was similar to the runoff that occurred by about 40mm/day rainfall. And average snowmelt runoff was not significantly different from the runoff that occurred by 25.5 mm/day rainfall. Average values of SS loads and FWMCs were 5,438 kg/day and 954.9 mg/L, respectively. SS loads and FWMCs were in the similar range with those that occurred by 39.0 mm/day and 53.0 mm/day rainfall, respectively. Daily SS and COD loads and FWMCs occurred by snowmelt and rainfall were analyzed not to be significantly different. Overall assessment led that the NPS pollution loads by snowmelt runoff had a similar characteristics with the loads by about 40 mm/day rainfall runoff. It was recommended that the agricultural fields in snowy region needs to managed not only for rainfall runoff but also snowmelt runoff for an effective water quality management.

• 한국축산식품학회지
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• 제38권3호
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• pp.476-486
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• 2018

In this study, the droplet size distribution, rheological properties, and stability of dairy cream-based emulsions homogenized with different sucrose fatty acid ester (SFAE, a non-ionic small-molecule emulsifier) concentrations (0.08%, 0.16%, and 0.24% w/w) at different homogenization pressures (10 MPa and 20 MPa) were examined. Homogenization at a high pressure resulted in a smaller droplet size and narrower droplet size distribution. The D[4,3] (volume-weighted mean) and D[3,2] (surface-weighted mean) values of the emulsions decreased with an increase in the SFAE concentration. The flow properties of the emulsions homogenized with SFAE showed shear-thinning (n=0.21-0.46) behavior. The apparent viscosity (${\eta}_{a,10}$) and consistency index (K) of the homogenized emulsions were lower than those of the control sample that is non-homogenized and without SFAE, and decreased with an increase in SFAE concentration. The storage modulus (G') and loss modulus (G") of all emulsions homogenized with SFAE were also lower than those of the control sample. The stability of all emulsions with SFAE did not show any significant change for 30 d at $5^{\circ}C$. However, the emulsions stored at $40^{\circ}C$ were unstable over the storage period. Therefore, the addition of SFAE enhanced the stability of dairy cream emulsions during storage at refrigeration temperature ($5^{\circ}C$).

• 한국물환경학회지
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• 제24권1호
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• pp.69-77
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• 2008

This study was conducted to know the characteristics of agricultural non-point source pollutants runoff by rainfall events at the upper catchment of Goseong reservoir in Gonjy city, Chungnam Province. For this study, the monitoring sites of the research catchment were set nineteen during the research period (between June 2005 and October 2006). Average runoff coefficient were observed 0.51 in 2005, 0.71 in 2006, respectively. The correlation coefficient (r) between the rainfall and peak-flow was investigated 0.787. By rainfall events, the water quality of the sites were shown like this : BOD 0.555~9.60 mg/L, T-N 0.01~13.50 mg/L, T-P 0.002~2.952 mg/L, and SS N.D~820.0 mg/L. The strong rainfall intensity was the most important factor of the soil erosion. The gabs of the arithmetic mean concentrations and the flow weighted mean concentrations were observed as the followings : BOD 0.0~29.2%, T-N 0.1~11.4%, T-P 0.4~95.2%, and SS 1.7~57.0% in 2005, and BOD 1.0~11.9%, T-N 0.7~7.3%, T-P 9.9~36.5%, and SS 6.6~36.5% in 2006, respectively. The BOD pollution load was 2,117 kg (36% of the total BOD loading of survey periods) while, T-N was 3,209.0 kg (27.9% of the total T-N loading of survey periods), T-P was 136.4 kg (37.4% of the total T-P loading of survey periods) and SS was 72,733.8 kg (51.8% of the total SS loading of survey periods) in the year 2005. In case of 2006, BOD load was 1,321.7, T-N was 2,845.8, T-P was 42.9, and SS was 16,275.8 kg, respectively.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2007년도 학술발표회 논문집
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• pp.951-955
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• 2007

본 연구에서는 산림유역과 농지와 임야가 혼합된 유역에서 발생하는 강우유출수의 유량가중평균농도를 분석하기 위해 강원도 춘천시에 위치한 강원학교 학술림, 유포리 및 월곡리 소하천을 대상으로 유량 수질 자료를 수집하여 분석하였으며, 유역별로 각각 21개의 유량가중평균농도를 산정하였다. 유역별 21개 강우사상에 대한 수질항목별 평균 유량가중평균농도 농도는 유포리(AW1) > 월곡리(AW2) > 학술림(FW) 순서로 농업유역의 유량가중평균농도가 산림유역에 비해 높은 것으로 나타났다. 연구유역의 유출량에 영향을 미치는 인자로는 강우량과 유역면적의 상관도가 높게 나타났으며, 강우량에는 강우강도가 영향을 미치는 것으로 나타났다. 대부분의 수질항목간의 상관도가 있는 것으로 나타났으나, 유기물 함량을 측정하는 COD의 경우 물속의 영양물질 양을 측정하는 T-N 및 T-P와 관계가 없는 것으로 나타났다.

• 한국습지학회지
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• 제14권4호
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• pp.503-518
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• 2012

지면에서 탄소수지를 모의하는 모형들은 주로 수직적인 탄소 플럭스에 주된 관심을 두어왔다. 반면에 수평 적인 탄소 플럭스에 관한 연구는 부족한 실정이다. 따라서 수평적인 탄소 플럭스의 흐름에 대해 연구하고자 유역 내 식생에 의해 생산되는 총 일차생산량(Gross primary production, GPP)과 유역에서 배출되는 총 유기탄소(Total Organic Carbon, TOC)의 교차상관분석을 실시하였다. 분석결과, GPP와 유역에서 배출되는 TOC의 유량가중 평균 농도는 서로 지체시간이 없을 경우에 가장 큰 상관관계를 보여주고 있음을 확인하였다. 또한 주기성이 고려된 상관구조를 살펴본 결과, 여름철의 TOC와 GPP 사이의 상관관계가 주기성이 고려되지 않았을 경우의 상관관계와 유사하게 나타났다. 이로부터 GPP와 TOC의 상관관계는 여름철에 맺어지는 GPP와 TOC 상관관계에 의해서 대부분이 규정되고 있음을 살펴볼 수 있었다. 이에 따라 식생에 의해 생산된 탄소와 유역에서 배출되는 유기탄소의 관계가 계절적으로도 긴밀한 관계가 있을 것이라 추측된다. 따라서 향후 연구는 계절에 따른 식생변수와 GPP와 TOC의 관계를 분석함으로서 조금 더 정량적으로 수평적인 탄소 플럭스 흐름에 대해 이해 할 수 있을 것으로 기대된다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2006년도 학술발표회 논문집
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• pp.997-1001
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• 2006

Organic compost has been widely applied to the cropland because it has been thought as Environmentally Sound Agriculture (ESA) in Korea. In this study, two-year indoor rainfall experiments were performed. Surface runoff and groundwater volume from 10% and 20% slope plots were measured and water quality samples were collected and analyzed for BOD, COD, T-P and T-N. Flow weighted mean concentration (FWMC) values were computed to assess effects of various fertilizer treatments. FWMC BOD values for organic compost treated plots were higher than chemical fertilizer treated plots. FWMC BOD values for 20% slope plots were higher than those from those for 10% slope plots. The similar trends were found for COD and T-P. FWMC T-N values for chemical fertilizer treated plots were higher than organic compost treated plots. FWMC T-N values for 10% slope plots were higher than those for 20% slope plots. In Korea, excessive use of organic compost has caused extremely high levels of organic matter contents at the cropland. Since organic compost is very slow in releasing its nutrients to the soil, farmers usually apply excessive organic compost for immediate effects and maximum crop yields, which has been causing soil and water quality degradations. Therefore, thorough investigations for better nutrient management plans are needed to develop the ESA strategy in Korea.

• 한국산학기술학회논문지
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• 제10권5호
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• pp.1026-1033
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• 2009

본 연구에서는 안성천 유역을 대상으로 토지지용별로 산지, 농경지, 도시지역을 표본지역으로 선정하여 비점오염원 원단위를 산정하였다. 그리고 강우시 유출수의 유출특성을 가장 잘 반영하는 유량가중평균농도를 산정하고, 유출오염부하량을 산정하였다. 유출계수가 높게 나타났던 1차 강우시가 2차 강우시보다 오염물질의 유량가중평균농도가 높게 나타나는 경향을 보였으며, 토지이용별 산정결과, 농지와 산지 같은 비도시지역보다 도시 지역에서 강우 유출시 높은 농도의 오염물질이 발생하는 것으로 나타났다. BOD 유출부하량은 산지, 농지, 도시 지역에서 1차 강우 시 각각 1,395kg/d, 1,623kg/d, 2,268kg/d로, 2차 강우시 각각 503kg/d, 512kg/d, 898kg/d로 산정되었다. 강우량 및 강우강도에 따라 토지이용별로 유출부하가 크게 다르게 나타났다. 토지이용별 원단위는 BOD 기준으로 도시지역이 72.7kg/ha/yr로 농경지(6.5kg/ha/yr)보다 12배 이상, 산지(9.5kg/ha/yr)보다 8배 이상 높게 나타나 도시지역이 비도시지역보다 단위면적당 비점오염부하가 매우 높은 것으로 나타났다.