• 한국농공학회논문집
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• 제47권3호
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• pp.59-68
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• 2005

The rainfall-runoff potential of Jangseong reservoir watershed was studied based on SCS (Soil Conservation Service, which is now the NRCS, Natural Resources Conservation Service, USDA) runoff curve number (CN) technique. Precipitation and reservoir operation data had been collected. The rainfall-runoff pairs from the watershed for ten years was estimated using reservoir water balance analysis using reservoir operation records. The maximum retention, S, for each storm event from rainfall-runoff pair was estimated for selected storm events. The estimated S values were arranged in descending order, then its probability distribution was determined as log-normal distribution, and associated CNs were found about probability levels of Pr=0.1, 0.5, and 0.9, respectively. A subwatershed that has the similar portions of land use categories to the whole watershed of Jangseong reservoir was selected and hydrologic monitoring was conducted. CNs for subwatershed were determined using observed data. CNs determined from observed rainfall-runoff data and reservoir water balance analysis were compared to the suggested CNs by the method of SCS-NEH4. The $CN_{II}$ measured and estimated from water balance analysis in this study were 78.0 and 78.1, respectively. However, the $CN_{II}$, which was determined based on hydrologic soil group, land use, was 67.2 indicating that actual runoff potential of Jangseong reservoir watershed is higher than that evaluated by SCS-NEH4 method. The results showed that watershed runoff potential for large scale agricultural reservoirs needs to be examined for efficient management of water resources and flood prevention.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2005년도 학술발표논문집
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• pp.540-545
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• 2005

Large scale projects of sea-land reclamation have been practiced mainly to enlarge farmland in Korea. Most projects produced estuarine reservoir with dike construction, which might result in water quality problems due to block of natural flowing of stream water to the sea. Applicability of a widely accepted watershed-based water quality assessment tool (BASINS) and its associated watershed model was evaluated on the Hwaong watershed in Korea. BASINS was found to be a convenient and powerful tool for assessment of watershed characteristics, and provided various tools to delineate the watershed into land segments and river reaches, reclassify land use, and parameterize for HSPF simulation. WASP5 is a general purpose modeling system for assessing the fate and transport of conventional and toxic pollutants in surface water bodies. This study involved selection and linkage of available models to be used as a tool in evaluating the effects of BMPs for control on reservoir water quality. Overall,.Linkage of BASINS/HSPF and WASP5 was applicable and found to be a powerful tool in pollutant loading estimation from the watershed and reservoir, and its use is recommended.

• 한국수자원학회논문집
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• 제53권12호
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• pp.1131-1142
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• 2020

본 연구에서는 농업용수 공급계획 및 수리시설설계에 적용하기 위한 논벼 수요량 추정에 있어서 증발산량 산정 방법을 농업용수 공급량을 기반으로 평가해 보았다. 증발산량 산정 방법은 기존의 논벼 수요량에 적용 되어온 Modifeid-Penman (MP) 방법과 최근에 농촌진흥청에서 작물계수 개발에 적용한 Penman-Monteith (PM) 방법이 고려되었다. 호남지역 한국농어촌공사 관할지구를 선정하여 기상특성을 분석하고, MP 방법과 PM 방법에 의한 논벼 수요량을 산정하여 현장의 용수 공급량과 비교분석하여 증발산량의 적용성을 평가해 보았다. 대상지구의 기상특성은 30년 기간 연평균 및 논벼 생육기간 평균기온은 증가하고 연평균 강우량과 논벼 생육기간 강우량은 감소하는 경향을 보였다. 이러한 기상특성은 증발산량 산정과 논벼 수요량 결과에 직접적인 영향을 미치는 것으로 파악되었다. 두 증발산량 산정방법 적용에 의한 수요량 결과 비교분석에서 MP 방법에 의한 논벼 수요량이 PM 방법 보다 더 높게 산정되는 경향을 보였으며, 농업용수 공급량과의 비교분석에서 MP 방법이 PM 방법 보다 더 적은 격차를 나타내었다. 따라서 현장여건이 반영된 농업용수 공급량 기반 평가에서 논벼 수요량 산정에 MP 방법을 적용하는 것이 농업용수 관리계획 및 용수공급 안정성 확보에 유리할 것으로 사료된다.

• 한국농공학회논문집
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• 제60권2호
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• pp.45-53
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• 2018

Demand for essential resources including water, energy and food is rapidly increasing due to climate change, population growth and urbanization. To solve this problem, the concept of water-energy-food nexus has been introduced, and many countries have been trying to acquire the Nexus technology that can maximize the efficiency by analyzing the interconnection between resources. In this regard, this study attempted to estimate the probable maximum water thermal energy in the dam based on the water-energy nexus concept. The estimation of the probable maximum water thermal energy was implemented to monthly water storage of the largest dams in the four major river systems. As a result of analyzing the estimated monthly water thermal energy from 2000 to 2016, Soyang River dam has the largest probable maximum water thermal energy, and Sumjin River dam has the smallest. However, the probable maximum water thermal energy was small in common between March and April, between September and October due to the small temperature difference between the ambient air and the dam water. Also, according to the characteristics of the dam, Daecheong dam and Soyang River dam were beneficial for supplying water thermal energy for heating, and Sumjin River dam and Andong dam were advantageous for supplying water thermal energy for cooling. Our findings can be useful to realize the water-energy-food nexus by increasing the utilization and value of water resources as well as expanding the roles and functions of dams as a starting point to use dam water thermal energy.

• 농촌계획
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• 제29권1호
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• pp.37-49
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• 2023

Active attention and effort are needed to develop an integrated water management system in response to climate change. In this study, it proposed models for cross-use of agricultural water and river maintenance water using sewage treatment water as an integrated water management system for the Yeongsan River. The impact of the integrated water management models was assessed by applying the concept of Nexus, which is being presented worldwide for sustainable resource management. The target year was set for 2030 and quantitatively analyzed water, energy, land use and carbon emissions and resource availability index by integrated water management models was calculated by applying maximum usable amount by resource. An integrated water management system evaluation model using the Nexus concept developed in this study can play a role that can be viewed in a variety of ways: security and environmental impact assessment of other resources. The results of this research will be used as a foundation for the field of in the establishment of a policy decision support system to evaluate various security policies, as we analyzed changes in other factors according to changes in individual components, taking into account the associations between water, energy, food, and carbon resources. In future studies, additional sub-models need to be built that can be applied flexibly to changes in the future timing of the inter-resource relationship components.

• 한국농공학회지
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• 제25권2호
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• pp.42-53
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• 1983

In Korea, the demand for water is increasing greatly due to Korea's raqid economic progress which is similar to Japan's. A correct estimation of the runoff factors is the question that must be settled first to establish the appropritae plans for water use and water resources. of these plans the estimation of catchment evapotranspiration for every river basin is the subject of the most importance. It is impossible theoretically to measure evapotranspiration directly, because it is an at mospheric translatory phenomenon. Many approaches have been devised to estimate evapotranspiration, but each of these methods estimates from information taken from a specified point, and these methods are considered incomplete for estimating catchment evapotranspiration. In this paper, the seasonal evapotranspiration estimating method that was proposed by Linsly and was applied in the Kamigamo exprimental basin (subjected to Kyoto Univ.) by Takase et al, was used for the Geum river which is the main river in Korea. Conclusion of experiment. 1) The average annual Ec in this river basin from 1966 to 1972 was 470mm. That is considered appropriate since the average value for the six other large river basin in korea was 485mm. 2) The Ec/Ep and Ec/Epm ratios were 0.43 and 0.52, respectively (Ec : estimated evapotranspiration by water balance method, Ep : average pan evaporation, Epm : evaporation by Penman method). The seasonal Ec/Ep ratios were : 0.4 in spring, 0.6 in summer, 0.4 in autumn and 0.2 in winter. These are rather small when compared to Japan's or England's. 3) The reason for this was that the precipitational difference in wet and dry seasons were greater, an there was not sufficient soil moisture harmonize with the evapotranspiration capacity in the dry season, and that evapotranspiration was small due to the numerous barren mountains.

• 한국농공학회논문집
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• 제48권1호
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• pp.13-23
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• 2006

In 1998, Food and Agriculture Organization addressed that FAO Modified Penman method possibly over-estimates consumptive use of water comparing to the measured reference crop evapotranspiration (PET) and Penman-Monteith method can be better choice for accurate PET estimation. Nevertheless it is still difficult to find research efforts about paddy rice crop coefficient for Penman-Monteith method. This study aims to estimate paddy rice crop coefficients for Penman-Monteith and FAO modified Penman methods in the manner of comparing two equations. To estimate the crop coefficients, measured evapotranspiration data during 1982-1986 and 1995-1997 were used. The average Penman-Monteith crop coefficients ranged from 0.78 to 1.58 for translated paddy rice and from 0.87 to 1.74 for flood-direct seeded paddy rice. The average FAO Modified Penman crop coefficients ranged from 0.65 to 1.35 for translated paddy rice and from 0.70 to 1.58 for flood-direct seeded paddy rice.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2005년도 학술발표논문집
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• pp.20-25
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• 2005

In 1998, Food and Agriculture Organization addressed that FAO Modified Penman method possibly overestimates consumptive use of water comparing to the measured reference crop evapotranspiration (PET) and Penman-Monteith method can be better choice for accurate PET estimation. Nevertheless it is still difficult to find research efforts about paddy rice crop coefficient for Penman-Monteith method. This study aims to estimate paddy rice crop coefficients for Penman-Monteith method. To estimate the crop coefficients, measured evapotranspiration data during 1982-1986 were used. The average Penman-Monteith crop coefficients for transplanted paddy rice were ranged in $0.78\;{\sim}\;1.58$.

• 한국농공학회논문집
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• 제49권3호
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• pp.11-20
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• 2007

Estimation of crop consumptive use is a key term of agricultural water resource systems design and operation. The 10-year return period drought has special aspects as a reference period in design process of irrigation systems in terms of agricultural water demand analysis so that crop evapotranspiration (ETc) about the return period also has to be analyzed to assist understanding of crop water requirement of paddy rice. In this study, The ETc of 10-year return period drought was computed using frequency analysis by 54 meteorological stations. To find an optimal probability distribution, 8 types of probability distribution function were tested by three the goodness of fit tests including ${\chi}^2$(Chi-Square), K-S (Kolmogorov-Smirnov) and PPCC (Probability Plot Correlation Coefficient). Optimal probability distribution function was selected the 2-parameter Log-Normal (LN2) distribution function among 8 distribution functions. Using the two selected distribution functions, the ETc of 10-year return period drought was estimated for 54 meteorological stations and compared with prior study results suggested by other researchers.

• 한국환경농학회지
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• 제33권1호
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• pp.37-43
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• 2014

BACKGROUND: Water quality data are collected less frequently than flow data because of the cost to collect and analyze, while water quality data corresponding to flow data are required to compute pollutant loads or to calibrate other hydrology models. Regression models are applicable to interpolate water quality data corresponding to flow data. METHODS AND RESULTS: A regression model was suggested which is capable to consider flow and time variance, and the regression model coefficients were calibrated using various measured water quality data with genetic-algorithm. Both LOADEST and the regression using genetic-algorithm were evaluated by 19 water quality data sets through calibration and validation. The regression model using genetic-algorithm displayed the similar model behaviors to LOADEST. The load estimates by both LOADEST and the regression model using genetic-algorithm indicated that use of a large proportion of water quality data does not necessarily lead to the load estimates with smaller error to measured load. CONCLUSION: Regression models need to be calibrated and validated before they are used to interpolate pollutant loads, as separating water quality data into two data sets for calibration and validation.