• 한국관개배수논문집
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• 제13권2호
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• pp.262-273
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• 2006

The Soil and Water Assessment Tool (SWAT) model has been widely used in hydrology and sediment simulation worldwide. In most cases, the SWAT model is first calibrated with adjustments in model parameters, and then the validation is performed. However, very little study regarding the effects on SWAT estimation of subwatershed delineation was performed. Thus, the SWAT model was applied to the Doam-dam watershed with various threshold values in subwatershed delineation in this study to examine the effects on the number of subwatershed delineated on SWAT estimation. It was found the flow effect of subwatershed delineation is negligible. However there were huge variations in SWAT estimated sediment, T-N, and T-P values with the use of various threshold value in watershed delineation. Sometimes these variations due to watershed delineation are beyond the effects of parameter adjustment in model calibration and validation. The SWAT is a semi-distributed modeling system, thus, the subwatershed characteristics are assumed to be the same for all Hydrologic Response Unit (HRU) within that subwatershed. This assumption leads to variations in the SWAT estimated sediment and nutrient output values. Therefore, it is strongly recommended the SWAT users need to use the HUR specific slope length and slope value in model runs, instead of using the slope and the corresponding slope length of the subawatershed to exclude the effects of the number of subwatershed delineated on the SWAT estimation.

• 한국GIS학회:학술대회논문집
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• 한국GIS학회 2008년도 공동추계학술대회
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• pp.151-152
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• 2008

The planning and management of the watershed environment require huge amount of information regarding almost all aspects of natural and manmade features of the area. Until lately this study could be achieved through days of exhaustive surveys map generation and tedious calculations. Remote sensing and GIS provides huge temporal database for an area and GIS provides the powerful tool for spatial and non-spatial analysis of remotely sensed data. The paper highlights the assessment of land potentiality using weighed overlay analysis with drainage density, soil, slope and lineament, LULC map was used to identify the utilization area of the watershed. The arithmetic overlay analysis was performed with potential and utilization layer to assess the availability of land for the future development.

• 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.

• 한국측량학회지
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• 제17권3호
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• pp.245-256
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• 1999

유역추출은 수문학적 유역을 인식하기 위해 지표면을 흘러가는 물의 흐름을 추적하는 과정이다. 지표면의 물 흐름과 유역을 수작업 및 자동으로 추적하는 기법들이 개발되어 왔다. 그러나, 준평야지는 지형 특성상 유역추출에 많은 어려움을 내포하고 있기 때문에 본 연구에서는 준평야지의 유역추출알고리즘을 개발하는데 그 목적을 두고 있다. 본 연루에서는 topogrid를 이용한 강제배수 알고리즘과 하천자료에 지형자료를 연계함으로서 준평야지의 유역을 추출하였다. 본 연구를 수행한 결과 준평야지에서는 단순히 TIN을 구성하여 유역추출을 위한 Source Grid를 생성하는 것 보다 Topogrid를 이용한 강제배수 알고리즘이 유역추출을 위한 좋은 Source Grid를 생성해 줌을 알 수 있었다. 또한 준평야지에서 표고와 하천자료를 연계하여 유역을 자동추출하여 수작업에 의한 유역과 비교한 결과 상당히 좋은 결과를 나타냄을 알 수 있었다.

• 한국관개배수논문집
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• 제6권2호
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• pp.28-36
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• 1999

The concept of loading functions was implemented to estimate runoff and nutrient concentrations from nonpoint sources. The model was applied to a sub-watershed of Bokha watershed in Ichon, Kyonggi-Do, to investigate its limitations. Runoff prediction base

• 한국관개배수논문집
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• 제3권2호
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• pp.11-19
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• 1996

Lake Soyang, the largest man-made lake in Korea, has been experiencing water quality degradation because of excessive nutrient loads from the watershed. Objective of this paper is to describe land uses in and TP and TN loading characteristics from the lak

• 한국농공학회논문집
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• 제61권4호
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• pp.87-96
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• 2019

The objective of this study was to develop a general inundation modeling technique considering the effect of drainage delay in the paddy field districts. In most studies, farmland inundation simulations have been conducted using previously developed watershed models. However, the water cycle in the paddy fields has a different structure from that of the general watershed, and the effect of the drainage delay should be considered. In this study, the drainage delay algorithm was developed using water balance equation, and the inundation modeling was performed for inundation-prone paddy fields located near Doowol stream. As a result, the depth of inundation was 43.1 cm and 45.2 cm, respectively, due to the 100-year and 200-year frequency rainfall. With the operation of drainage pump ($0.1m^3/s$), inundation depths decreased by 5.8 cm and 6.0 cm, respectively, and inundation time reduced by 20 hours and 21 hours, respectively for the 100-year and 200-year frequency rainfall. The result showed that the general inundation modeling technique developed in this study could reflect the effect of drainage delay due to the rise of external water level and the flooding reduction effect by operation of drainage pump. The results of this study are expected to be useful to establish measures for damage caused by farmland inundation.

• 한국농공학회지
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• 제30권4호
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• pp.45-61
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• 1988

The purpose of this study is to develop regression equations between annual specific sedi- ment of reservoirs and physiographic factors of watersheds. 122 irrigation reservoirs, which have irrigation areas equal to or larger than 200 ha, located in Korea except Cheju province are used in the analysis. Simple regression analyses between the specific annual sediment and each of the physical characteristic factors of the reservoirs are carried out at first. Then, multiple regression analyses between the annual specific sediment and the physical characteristic factors with high correlation coefficients in the simple regression analyses are made. The results obtained from this study are as follows : 1. The results of the sirnple regression analyses show that in each province the watershed area, the length of mainstream, the circumferential length of watershed have high cor- relation coefficients (R=0.814-0.986), and that drainage density, reservoir capacity per watershed area, drainage frequency, basin relief have low correlation coefficients (R=0. 387-0.955). 2. The purposed multiple regression equations between the annual specific sediment of reservoirs and three major characteritic factors of watersheds, namely, the watershed area, the circumferential length of watershed, and the length of mainstream, are proposed as given in Table 2. 3. The result of the simple regression analyses with respect to the reservoir elevation except Jeonnam province, which has very different characteristics comparing to other provinces, shows that watershed area, main stream length and circumferential length have high correlation coefficients (R=0.806-0.884) in low-elevation reservoirs and intermediate- elevation reservoirs, but low correlation coefficients (R=0.639-0.739) in high-elevation reservoirs. 4. With respect to the reservoir elevation, the proposed multiple regression equations bet- ween the annual specific sediment of reservoirs and the three major characteristic factors of watershed which have high correlation coefficients are proposed as given in Table 5.

• 한국관개배수논문집
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• 제4권1호
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• pp.51-60
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• 1997

The pattern of droughtflow which is important for oater resources development depends on the characteristics of watershed. Droughtflow depleted from the watershed mainly embedded with metamorphic rocks is much more than that from the watershed mainly embe

• 한국관개배수논문집
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• 제16권1호
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• pp.41-45
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• 2009