• 산업기술연구
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• 제25권B호
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• pp.27-35
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• 2005

Non-point source pollution, which is found in soil, urban area, and agricultural area, is difficult to have its amount to be estimated. Moreover, it is hard to come up with a counterplan to cope with this pollutant. Hence, the watershed of Mandae-cheon located at the upstream of Soyang Lake was chosen as our site of study. We analyzed the relationship between precipitation level of each month and pollution load in the watershed by using statistical methods: measuring BOD, T-N and T-P - which are the causes of eutrophication - in the water; and analyzing the changes in water quality caused by precipitation level of nth.

• 한국농공학회논문집
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• 제51권6호
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• pp.17-23
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• 2009

The Soil and Water Assessment Tool (SWAT) model was used in this study to evaluate the hydrologic impacts by the impervious surface change in the farm region. The model was calibrated and validated by using four years (1999-2002) of measured data for the Gyeongancheon watershed in Korea. The simulation results agreed well with observed values during the calibration and validation periods. Land use scenarios including various changes of the plastic film house area in the farm region were applied to assess their effects on watershed hydrology. The results indicated that the surface direct (5.6%~14.0%) and total runoff (0.8%~1.5%) increased, but the groundwater discharge (10.7%~27.7%) and evapotranspiration (1.5%~3.3%) decreased as the plastic film house area (5.7%~12.4%) increased.

• 한국환경과학회지
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• 제18권9호
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• pp.1057-1063
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• 2009

Since Jeju island has depended a water resource on the underground water because of a poor development of the surface flow, Jeju island is in need of the surface resource development to prevent the future shortage of the underground water due to excessive development and use of it. The study shows that the SWAT model(continuous rainfall-runoff model) is applied to estimate the outflow in the drainage watershed area, where it has been urbanized through the change of the land, such as a tourism development, cultivation, housing, and impervious layer road development. Near Oaedo watershed area in Jeju island, weather and topographical SWAT input data were collected, and compared the outflow change of past and present.

• 한국환경과학회지
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• 제24권11호
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• pp.1473-1483
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• 2015

In this study, a digital terrain analysis had been performed for a mountainous watershed having wetlands. In order to consider the impact for wetland in the flow determination algorithm, the Laplace equation is implemented into the upslope accounting algorithm of wetness computation scheme. The computational algorithm of wetland to spatial contribution of downslope area and wetness was also developed to evaluate spatially distributed runoff due to the presence of wetland. Developed schemes were applied to Wangpichun watershed located Chuncuk mountain at Ulzingun, South Korea. Both spatial distribution of wetness and its histogram indicate that the developed scheme provides feasible consideration of wetland impact in spatial hydrologic analysis. The impact of wetland to downslope propagation pattern is also useful to evaluate spatially distributed runoff distribution.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2004년도 학술발표회
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• pp.646-650
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• 2004

The purpose of this study is to determine the optimal groundwater yield for a small rural watershed, which is necessary for effective groundwater management. The study area$(3.89km^2)$ is located in Kyungpook Sangju Yangchon-dong and hourly groundwater level in an observation well is observed and the data are used to verify the visual MODFLOW model. The groundwater model is applied in the same area to obtain optimal yield for 1992 and 1994, 1982. The optimal yield in this experimental watershed ranged $12.5\%\;to\;14.0\%$ of the annual infiltration rate.

• 한국환경과학회지
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• 제24권11호
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• pp.1343-1362
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• 2015

As a result of analysis based on the observed data for BOD, COD and TOC in order to manage non-biodegradable organics in the Geumho River, COD/BOD ratio was analyzed as the occupying predominance proportion. In this study, the classification(changes in water quality measurement : increase, equal, decrease) and measurement of BOD and COD were analyzed for trends over the past 10 years from 2005 to 2014 in the Geumho River. The Geumho River is expected to need non-biodegradable organics management because BOD was found to be reduced 61.1% and COD was found to be increased 50%. As a result of the analysis of land use, the Geumho-A is a unit watershed area of $921.13km^2$, which is the most common area that is occupied by forests. The Geumho-B is a unit watershed area of $436.8km^2$, which is the area that is highest occupied by agriculture and grass of 24.84%. The Geumho-C is a unit watershed area of $704.56km^2$ accounted for 40.29% of the entire watershed, which is the area that is occupied by urban of 15.12%. Load of non-biodegradable organics, which is not easy biodegradable according to the discharge, appeared to be increased because flow coefficient of COD and TOC at the Geumho-B were estimated larger than 1 value. The management of non-point sources of agricultural land is required because the Geumho-B watershed area occupied by the high proportion of agriculture and field. In this segment it showed to increase the organics that biodegradation is difficult because the ratio of BOD and TOC was decreased rapidly from GR7 to GR8. Thus, countermeasures will be required for this.

• 한국물환경학회지
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• 제27권4호
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• pp.475-485
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• 2011

Lake Sihwa has a very unique watershed environment, surrounded by industrial, urban and rural catchment area with different land use. The first flush phenomenon was investigated in 3 catchment area. 4TG, representing the industrial area, shows rapid discharges of highly concentrated pollutants during the early stages of a storm and it is indicating a strong first flush effect. At AS, representing the urban area, the pollutant concentration reached its peak approximately 2~3 hours after the start of storm, which is a strong first flush effect did not appear. JJB and MS represent the rural areas, the PEMC analysis results suggest that highly concentrated pollutants were discharged during the middle and latter stages of a storm, instead of early pollutant runoff due to the effects of rainwater runoff.

• 한국농공학회논문집
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• 제48권3호
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• pp.23-34
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• 2006

This study reviews the applicability of the GWLF (Generalized Watershed Loading Function) model, which is based on a loading function that requires only a relatively small amount of data, in a small agricultural watershed. The hydrological data was collected from 1996 to 2004 for a study area based on the HP#6 upper stream reservoir small watershed area. This data was then used to calibrate and verify the model. A simulation based on the model yielded $R^2$ values of $0.47\sim0.89$. This is considered to have high applicability when compared to the simulation and the observed results, which yielded relatively high values of $R^2$ for SS (Suspended Solid), TN (Total Nitrogen), and TP (Total Phosphorus) of 0.58, 0.47 and 0.62, respectively. This study provides a useful approach fur researchers selecting appropriate models to use the insufficient measuring data for rural watersheds.

• 한국환경농학회지
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• 제19권5호
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• pp.370-374
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• 2000

At this study, the monitoring network of water quality was established in the agricultural watershed an area 14,960 ha of the central southwest of Korea. Loads of nitrogen and phosphorus by agricultural land use were quantified bases on total amounts of stream flow. The land were used as a lowland paddy, an upland and a forest about 12.14 % (1,815 ha), 5.17 % (773 ha) and 80.31 % (12,015 ha) of the area, respectively. For six months, from May 1 to October 31, 1999, the total precipitation was 970 mm and the total amount of stream flow was $80,281,000\;m^3$. In the load of agricultural non-point sources relevant to land use, total-N was 138,413 kg, then ammonia-N 13,362 kg, nitrate-N 124,629 kg, and total-P 157 kg. The loss of nutrient which from application of chemical fertilizer were 38.0% in nitrogen and 0.1% in phosphorus to input chemical fertilizer in the watershed.

• 물과 미래
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• 제17권2호
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• pp.107-112
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• 1984

저수지내의 퇴사량을 추정하기 위하여 국내 3개 유역의 66개 관개용 저수지의 퇴사실측자료를 사용하여 저수지 퇴사량과 유역면적, 토사포착효율, 유역의 경사, 유역의 형상계수 및 저수지퇴사기간간의 상관관계를 단순회귀모형과 다도수회귀모형으로 제안하였다. 제안된 모형의 적합성을 실측자료로부터 검정하였으며 그 결과 다도수회귀모형에 의한 것이 단순회귀모형에 의하여 산정된 것보다 훨씬 정확한 것으로 판정되었다. 저수지의 년비유사량과 유역면적 및 토사포착효율과 상관시켰다. 저수지내의 년평균퇴사율과 년평균저수지내용적용적의 변동은 토사포착율에 의해 크게 좌우됨을 알았다.