• Water Engineering Research
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• 제6권3호
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• pp.101-112
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• 2005

This paper presents the state of the art of the CFD applications to vegetated open-channel flows. First, important aspects of the physics of vegetated flows found through the laboratory experiments are briefly reviewed. Then, previous CFD applications to one-dimensional vertical structure, partly-vegetated flows, compound open-channel flows with floodplain vegetation, and fully three-dimensional numerical simulations are reviewed. Finally, topics for further researches such as relationship between the resistance and flexural rigidity, additional drag due to foliages, and melting the experience of CFD with the depth-averaged modeling, are suggested.

• 환경정책연구
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• 제6권2호
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• pp.47-70
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• 2007

최근 들어 환경생태의 중요성 인식과 풍요롭고 환경적으로 안정된 생활을 영위하고자 하는 국민들의 욕구가 증대하고 있다. 이에 따라 물을 대하는 국민의 요구도 수질 및 수량관리에서 한 걸음 더 나아가 하천의 생태계를 보전하고 하천의 정상적인 기능을 회복시켜 건전한 하천환경 유지에 대한 수요도 증가하고 있다. 이러한 국민의 요구에 부응할 수 있도록 환경유량에 대한 개념을 정립하여 하천관리는 환경유량과 연계하여 취수를 허락하고, 자연에 가깝게 생태계를 보전하고 관리하여야 한다. 우리나라에서 환경유량은 하천관리 측면에서의 하천유지용수 개념으로 도입되었다. 우리나라에서 하천유지용수 산정은 아직도 인간 위주의 용수이용기능을 중점적으로 고려한 것으로 순수한 환경유량의 의미로서 환경생태적 관점에서 정의되고 강조되지 못했다. 환경유량은 하천유지용수에서 더 발전하여 생태계의 건전성 유지에 강조를 둔 새로운 개념으로 전환되어야 한다. 즉, 환경유량은 하천의 기능과 하천이 가지는 본래의 가치를 유지하기 위해 필요한 유량으로 정의하고 이는 각종 경제활동 유지를 위한 용수 공급, 위락, 심미, 수질, 수력발전, 주운 등을 위한 용수와 동일가치 또는 그 이상에서 고려하여야 한다.

• Korean Journal of Hydrosciences
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• 제3권
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• pp.105-113
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• 1992

Various modeling approaches to study a long term behavior of streamflow or groundwater storage have been conducted. In this study, a Multivariate AR (1) Model has been applied to generate monthly flows of the one key station which has historical flows using monthly flows of the three subordinate stations. The Model performance was examined using statistical comparisons between the historical and generated monthly series such as mean, variance, skewness. Also, the correlation coefficients (lag-zero, and lag-one) between the two monthly flows were compared. The results showed that the modeled generated flows were statistically similar to the historical flows.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2005년도 학술발표회(1)
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• pp.592-593
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• 2005

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2005년도 학술발표회(1)
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• pp.778-779
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• 2005

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2005년도 학술발표회(1)
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• pp.780-781
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• 2005

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2005년도 학술발표회(2)
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• pp.1271-1273
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• 2005

• 한국농공학회논문집
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• 제46권7호
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• pp.71-80
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• 2004

A system for estimating daily paddy irrigation water requirements was developed to simulate daily stream flows that reflect various upstream and downstream return flows from river basin. Evapotranspiration in paddy fields was estimated using the modified Penman equation. Daily irrigation water requirements of paddy fields were calculated by multiplying the paddy area and the daily decrease in ponding depth. The system was constructed almost completely using images, grids, etc. in Visual Basic 6.0. The developed model was verified in the Damyang dam, and was used to estimate daily paddy irrigation water requirements at 12 small watersheds in Geum river basin for 20 years, from 1983 to 2002, covering paddy field areas of $3,332\~26,422$ ha. The results on the runoff analysis on the inflow to the Daecheong multi-purpose dam with various return flows were satisfactory. They were reasonable compared to the scenario where return flows were not considered.

• Water Engineering Research
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• 제1권1호
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• pp.63-74
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• 2000

This paper presents a two- phase search scheme for optimal pipe expansion of expansion of existing water distribution systems. In pipe network problems, link flows affect the total cost of the system because the link flows are not uniquely determined for various pipe diameters. The two-phase search scheme based on stochastic optimization scheme is suggested to determine the optimal link flows which make the optimal design of existing pipe network. A sample pipe network is employed to test the proposed method. Once the best tree network is obtained, the link flows are perturbed to find a near global optimum over the whole feasible region. It should be noted that in the perturbation stage the loop flows obtained form the sample existing network are employed as the initial loop flows of the proposed method. It has been also found that the relationship of cost-hydraulic gradient for pipe expansion of existing network affects the total cost of the sample network. The results show that the proposed method can yield a lower cost design than the conventional design method and that the proposed method can be efficiently used to design the pipe expansion of existing water distribution systems.

• 한국농공학회논문집
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• 제58권1호
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• pp.73-80
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• 2016

The aim of this study is to analyze the contribution of regional water resources through the gap between water used for rice production and water used for consumption. The blue water use for rice production and for consumption was quantified and the regional blue water flows were estimated using the virtual water concept from 1995 to 2010. About $1134.4Mm^3/yr$ of blue water flowed among the provinces and metropolises of Korea, and about 28.5 % of total blue water flows came from Jeonnam province. In addition, blue water usage for rice was classified into three categories: water for production, internal consumption, and overproduction in each region. In Jeonnam, $633.8Mm^3/yr$ of blue water totally used for rice production, and 50.9 % and 15.5 % were used for external and internal rice consumption, respectively. The other 33.6 % was used for over production of rice for food security. This study assumed the blue water flows depended on the gap between virtual water use for rice production and consumption. However, the analysis of regional blue water usage and flows might show the importance of other region's water resources, and make policy decision-makers aware of the integrated water management among the regions.