• 한국조경학회지
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• 제27권2호
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• pp.41-50
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• 1999

The purpose of this study is to find out the changes in geomorphic characteristics of a small watershed when a golf course is constructed. The research site is a set of seven small watersheds including an 18-hole golf course that were randomly selected. The size, shape, and drainage network of watersheds were measured by using planimeter, watershed eccentricity, and stream order, respectively. In addition, a 25m$\times$25m mesh was used on topographic maps and grading plans in order to obtain the slope, elevation, and aspect of the watersheds. The major results of this research, while investigating of the changes in geomorphic characteristics of watersheds when a golf course is constructed, are as follows: 1. The size of watersheds is increased in accordance to the difference in elevation between the golf course site and the small watershed. 2. The watershed eccentricities are in general similar except for a few low-valued cases. 3. The changes in the average altitude and the gradient are more drastic with their bigger original values. 4. The aspects are changed more with decreasing elevation. 5. The stream order decreases in the case of a low watershed eccentricity. 6. The surface modification has a closer relationship to the slope rather than the size of effective use area. 7. With a steeper gradient and an excessively low gradient, the height of cutting/filling is increased.

• 한국농공학회지
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• 제35권1호
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• pp.40-49
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• 1993

The Objectives of this paper were to develop a modified tank model that is capable of simulating daily streamflow from a small watershed using daily watershed evapotranspiration and to test the applicability of the model to different watersheds. Tank model was restructured to consist of three series of tanks, each of which may mathematically reflect watershed runoff mechanisms from different components of surface runoff, interflow, and baseflow. And pan evaporation was correlated to potential evapotranspiration estimated from a combination method, and was multiplied by monthly crop and landuse coefficients, and watershed storage coefficient to estimate the watershed evapotranspiration losses. Ten watersheds were selected to calibrate model parameters that were defined using an optimization scheme, and the results were correlated with watershed parameters. Simulated daily runoff was compared to the observed ones from the tested watersheds. The simulating results were in good agreement with the observed values when optimal and calibrated parameters were used. Ungaged conditions were also applied to compare simulated values to the observed. And the results were in fair conditions for all the tested watersheds which differ considerably in their sizes, landuse types, and physiological features.

• 한국농공학회지
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• 제43권4호
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• pp.120-128
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• 2001

Pollution sources and their environmental contributions were investigated to select the best management practices for the effective control of water quality. The nitrogen isotope mass ratio was determined to estimate the nitrate sources and their contribution. Sampling sites were chosen by calculating effluent loads at each watershed. Two liters each of the surface water samples were collected from four sites at Bokha river and two sites and Gwanri river. They were sequentially prepared through distillation method and analyzed using an isotope ratio mass spectrometer(IsoPrime EA). As revealed by the experimental values obtained the mass ratio values ($\delta$$^{5}$ N) of watersheds with a large amount of nonpoint sources were less than +5 an indication that the samples were influenced by chemical fertilizers. However watersheds with large amount of point sources were influenced not only by chemical fertilizers but also by animal and municipal wastes. The mass ratio values of samples generally decreased during rainy days. But during dry days the mass ratio values well-reflected the nitrate sources and the condition of watersheds. Through this study the nitrogen isotope mass ratio has been found to be useful for estimating nitrate sources and their contribution to the rural watersheds.

• 한국환경생태학회지
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• 제29권2호
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• pp.236-249
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• 2015

The master plan of forest land management proposes forest watershed management that considers regional characteristics in order to overcome the problem of uniform forest land management. In order to manage the forest watersheds in Gyeonggi-do, this study classified 1,823 forest watersheds in Gyeonggi-do and attempted to understand their characteristics. It conducted a factor analysis and cluster analysis from the perspective of conservation value and development pressure using forest land indicators. In terms of conservation value, three factors were drawn: the topography factor, vegetation factor and public service factor, while in terms of development pressure, three factors were drawn: the easiness of development factor, economic benefits factor and development activity factor. Using these factors, forest watersheds were divided into three clusters in terms of conservation value while they were divided into three clusters in terms of development pressure. Using the results of the cluster analysis from a conservation-development perspective, the forest watersheds were classified into nine different types, and the characteristics were identified by each type. It is judged that the factors and clusters drawn as a result of the research accurately reflect the present conditions of Gyeonggi-do, and the nine types of forest watersheds have clear characteristics according to each type, which are judged to be utilized in forest management in the future.

• 물과 미래
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• 제24권4호
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• pp.85-91
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• 1991

전국에 산재해있는 20개 하천유역을 선정하여 월강우량과 유출량 자료를 사용하여 Rosenbrock의 Rotating Coordinate Search Method에 의해 Thomas abcd 모형의 변수를 결정하였다. 결정된 4개 변수와 2개 초기조건 변수는 유역의 기상인자, 지형인자 및 지질특성인자와 다종상관관계로 표시하였다. 이와 같이 구성된 Thomas 형의 월유출 모형을 2개 시험유역에 적용하여 실측 월유출량과 비교해 본 결과 본 모형은 춘추에는 약간 작게 추정하였고 그 외의 기간에는 약간 크게 추정하는 성향을 보였으나 대체로 만족스러운 결과를 주었으므로 미계측 하천의 월유출량 추정모형으로 사용 가능한 것으로 판단하였다.

• 한국물환경학회지
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• 제27권5호
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• pp.719-728
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• 2011

The results of investigation on the water quality of the unit watersheds in the Yeongsang/Seomjin River indicate that $BOD_5$, SS, T-P decrease in most of the unit watersheds. However, $COD_{Mn}$ and T-N increase since the Total Maximum Daily Loads (TMDLs). It is thought that $COD_{Mn}$, which is included non-biodegradable matters, is difficult to decrease only using by conventional biological treatment facilities and T-N is affected by non-point source, etc. The results of assessment on 3 years $BOD_5$ indicate that most of the unit watersheds were being improved except Yeongbon A, Seombon C and Yocheon B. In addition, it was found that T-P were also being improved except Yocheon B and Hwangryeong A. Consequently, water qualities of the unit watersheds have been improved in many cases since the TMDLs.

• 한국농공학회:학술대회논문집
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• 한국농공학회 1998년도 학술발표회 발표논문집
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• pp.533-540
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• 1998

In this study, to propose the methods predicting water qualities in rural areas, the methods which were based on the runoff ratio, the relationships between the pollutant load(L) and the water runoff(Q), and the relationships between the runoff ratio and the water runoff in Bokha stream watersheds were examined. As a result, we had acquired reliable the values of runoff ratio and the reasonable equations between the pollutant load(L) and the water runoff(Q) in Bokha stream watersheds. And it was noticed that the runoff ratio had tendency of varying directly proportional to the water runoff.

• 한국농공학회지
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• 제30권1호
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• pp.81-90
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• 1988

A physically-based, distributed hydrologic model ANSWERS is described and its test results with two small watersheds near the Banweol reservoir are presented. The sizes of the watersheds are 270 ha and 477 ha, respectively. The smaller one has a mild topography with 40 percent forest area. The other has a steeper slope and 87 percent forest area. The model parameters were calibrated using observed runoff data and used for storm runoff simulation. The simulated peak discharges were in good agreement with the data. The model underestimated the recession parts of hydrographa as compared to the observed ones.

• 한국농공학회지
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• 제26권2호
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• pp.125-132
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• 1984

A physically-based, distributed, parametric hydrologic model PARK 10 is described and its test results with three agricultural watersheds are presented. The model uses a rectangular grid system to depict hydrologic characteristics of a watershed, and thus, has potentials of identifying the effects of changes in land uses and/or other activities. The model is being tested with small watersheds in the pennisula.

• 한국농공학회지
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• 제32권4호
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• pp.89-98
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• 1990

The objectives of this study are to develop a deterministic, distributed, and event - oriented hydrologic watershed model and to test the applicabilities of the model to small watersheds. The resulting model SRAFEM, Storm Runoff Analysis by Finite Element Method, is capable of simulating storm runoff from small watersheds using two - dimensional overland flow and one - dimensional channel flow components by. kinematic approximations and finite element method. Two small watersheds were selected and the applicability of the model was tested. The test results showed that the mean simulation errors for runoff volume and peak flow were 13.9% and 19.1 % for Yeonwha watershed. They were 42.8% and 8.0% for Banweol watershed, respectively.