• Korean Journal of Hydrosciences
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• 제8권
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• pp.57-68
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• 1997

The daily soil water contents were obtained from the time domain reflectometry(TDR) method and energy balance-water budget approach with eddy correlation at the two small semiarid watersheds of Lucky Hills and Kendall during the summer rainy period. There was a comaprison of daily soil water content measured and estimated from these two different approaches. The comparison is valuable to evaluate the accuracy of current soil water content measuring system using TDR and energy balance-water budget approach using eddy correlation method at a small watershed scale. The degree of simiarity between the regressions of these two methods of measuring soil water content was explained by determining the correlations between these methods. Simple linear regression analyses showed that soil water content measured from TDR method was responsible for 58% and 63% of the variations estimated from energy balance-water budget approach with edy correlation at Lucky Hills and Kendall, respectively. The scatter plots and the regression analyses revealed that two different approaches for soil water content measurement at a small watershed scale have no significant difference.

• 한국물환경학회지
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• 제33권5호
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• pp.546-555
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• 2017

The Nutrient budget is one of the agricultural-environment indicators of OECD. A nutrient budget measures the surplus as the differential between the inputs and the outputs of within a certain boundary and within a specified period of time (i.e. one year). According to OECD, the annual nitrogen budget for Korea was $245kg\;N\;ha^{-1}$ in 2014, which corresponds to the first position among OECD countries. In Korea in 2014, about 90 % of livestock excreta was composted as solid and liquid manure, which are usually and customarily spread on agricultural land. The objectives of this study are intended to suggest methodology of the regional nitrogen budget as a nitrogen management tool, which considers conversion from raw excreta to composted manures based on the methodology of OECD/Eurostat, and application of the new method in an agricultural region of Korea. As a result, the calculated excess rate of hydrospheric nitrogen surplus was $251kg\;N\;ha^{-1}$ (in the region in 2014), which indicates the presence of potential risks emanating from excessive nitrogen, with regard to both export water and soil environments. The findings also assert that this was shown to be one of the most important elements in the nitrogen budget, which translates to the actual amounts of nitrogen lost during the solid composting process. To better understand the process and the reliability of the method, it is necessary to analyze the sensitivity of the relevant co-efficients used in the method in the near future.

• 한국물환경학회지
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• 제33권6호
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• pp.769-779
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• 2017

Nutrient (i.e., nitrogen and phosphorus) budgets are required under a 'Livestock Excreta Survey'. A nutrient budget is one of the agri-environmental indicators that calculates the difference between the inputs and outputs of the amount of nutrients within a certain boundary and for a certain time period (e.g., 1 year). In this study, a nutrients budget model was developed to effectively determine the surplus of nutrients within a region in Korea. The C# program language was used in order to facilitate the deployment of a graphical user interface (GUI) and to enhance compatibility. Also, the model was developed on Windows OS, which is the commonly used operating system in Korea. The model was based on the OECD/Eurostat nutrient budget method, and it was modified to consider manure composting procedures as well. There are key features of the nutrient budget model, including directly use of the original data sets from various input and output sources, and a collectively exchange of the address in different formats. The model can quickly show the results of various spatial and temporal resolutions with the same data, as well as perform a sensitivity analysis with coefficients and easily compareresults using tables and graphs. Further, it would be necessary to study the extension of the scope of utilization, such as the application of various nutrient budget methods. It would also be helpful to investigate both pre and postprocessing information such as linking input data through online systems.

• 한국환경과학회지
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• 제26권11호
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• pp.1255-1266
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• 2017

Phosphorus (P) is an essential and major nutrient for both plants and animals. However, anthropogenic P in the environment may cause severe problems such as the deterioration of water quality. Therefore, it is essential for the Korean government to manage P in the agricultural sector. The annual P budget for Korea was 46 kg P ha-1 in 2013, placing Korea in second among Organisation for Economic Co-operation and Development (OECD) countries. P surplus and deficiency in agricultural lands can be estimated according to the P budget, which is one of the OECD agri-environment indicators. In the P budget, it is important to ensure consistency in the input-output data sources, in order to apply national and regional policies for the environmentally sound management of agricultural P. This study examines the impacts on the input-output data sources in the regional P budget in Korea. P budgets were between 99-145 kg-P/ha, depending on different data sources. We suggest two recommended data combinations (DC 1 and DC 2) for reliability of the data. P budgets calculated using DC 1 and DC 2 were 128 kg-P/ha and 97 kg-P/ha, respectively. According to the results, one of the core factors affecting P budgets was crop production. In this study, DC 2 was recommended rather than DC 1 in order to consider the cultivated areas for various crops. It is also necessary to analyze the sensitivity of the coefficients used in P budget in the future.

• 한국토양비료학회지
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• 제48권4호
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• pp.246-254
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• 2015

This study explored the effect of rainfall pattern and soil characteristics on water management in rice paddy fields, using a soil water balance model, BUDGET. In two sites with different soil textural group, coarse loamy soil (Gangseo series) and fine soil (Hwadong series), respectively, we have monitored daily decrease of water depth, percolation rate, and groundwater table. The observed evapotranspiration (ET) was obtained from differences between water depth decrease and percolation rate. The root mean square difference values between observed and BUDGET-estimated ET ranged between 10% and 20% of the average observed ET. This is comparable to the measurement uncertainty, suggesting that the BUDGET model can provide reliable ET estimation for rice fields. In BUDGET model of this study, irrigation requirement was determined as minimum water need for maintaining water-saturated soil surface, assuming 100 mm of bund height and no lateral loss of water. The model results showed different water balance and irrigation requirement with the different soil profile and indicated that minimum percolation rate by plow pan could determine the irrigation requirement of rice paddy field. For the condition of different rainfall distribution, the results presented different irrigation period and amounts, representing the importance of securing water for irrigation against different rainfall pattern.

• 대한토목학회논문집
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• 제13권1호
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• pp.89-96
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• 1993

수자원시설물의 설계에 이용되는 기존의 물수지분석은 수자원의 공간적 분포를 고려하지 못하는 단점이 있다. 특히 많은 수자원의 외부공급량이 있고, 공급 대상지역이 중복될 경우 기존의 물수지분석을 적용할 경우 설계치가 과대 산정될 수 있다. 따라서 본 연구에서는 수자원의 공간적 분포를 고려한 물수지분석 방법을 제시하고, 수자원이용이 대단히 복잡한 동진강, 만경강유역을 포함하는 새만금사업지역을 대상으로 새로운 방법을 적용하였다.

• 한국물환경학회지
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• 제28권2호
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• pp.238-246
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• 2012

Organic matters budget in Lake Hoengseong were monthly investigated from April 2009 to November 2009. The intense rainfall occurred at between July and August and the hydrological factors were highly varied during the rainfall season. By the concentrated rainfall, the elevation, influx and efflux were sharply increased and the turbid water was also flowed into the middle water column in Lake. The inflow of turbid water increased the nutrient concentrations in water body and this appears to stimulate of phytoplankton regard as the primary productivity of influx of organic matter. Monthly average concentration of dissolved organic carbon (DOC) was generally higher than the particulate organic carbon (POC) concentration in Lake, but Temporal and spatial variation of POC concentration was higher than DOC and the maximum POC concentration was recorded in surface water in August, had the highest phytoplankton biomass. Organic carbon concentration in inflow site was rarely changed during the dry season, but the concentration was rapidly increased by the initial intense rainfall. In organic matters budget, the most of the organic matters was inflowed from the inflow site at rainfall season. Especially, the influx of allochthonous organic matters during the intense rainfall was 72.4% in the total influx organic matters.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2021년도 학술발표회
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• pp.145-145
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• 2021

Water distribution networks (WDNs) are designed to satisfy water requirement of an urban community. One of the central issues in human history is providing sufficient quality and quantity of water through WDNs. A WDN consists of a great number of pipelines with different ages, lengths, materials, and sizes in varying degrees of deterioration. The available annual budget for rehabilitation of these infrastructures only covers part of the network; thus it is important to manage the limited budget in the most cost-effective manner. In this study, a novel pipe replacement scheduling approach is proposed in order to smooth the annual investment time series based on a life cycle cost assessment. The proposed approach is applied to a real WDN currently operating in South Korea. The proposed scheduling plan considers both the annual budget limitation and the optimum investment on pipes' useful life. A non-dominated sorting genetic algorithm is used to solve a multi-objective optimization problem. Three decision-making objectives, including the minimum imposed LCC of the network, the minimum standard deviation of annual cost, and the minimum average age of the network, are considered to find optimal pipe replacement planning over long-term time period. The results indicate that the proposed scheduling structure provides efficient and cost-effective rehabilitation management of water network with consistent annual budget.

• 한국수자원학회논문집
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• 제36권1호
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• pp.61-74
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• 2003

본 연구(II)는 연구(I)에서 제안한 상수관로의 노후도 예측에 근거한 최적 개량 모형을 A시를 대상으로 이를 적용하였다. 노후도 예측 모형은 굴착 및 실험이 필요한 14개 항목과 굴착 및 실험이 필요하지 않은 9개 항목을 구분하여 각각 관의 노후도 등급을 산정하였다. 노후도 예측 모형 적용 결과 항목개수에 따른 등급의 차는 l~2% 이내로 굴착 및 실험을 하지 않고도 노후도 예측이 가능한 것으로 나타났다. 최적 개량 모형은 노후도 항목별 최대 잔존수명과 제약조건 유무로 구분하여 적용하였다. 적용결과 항목별 최대 잔존수명의 증가에 따라 개량 시기 및 비용이 증가하였다. 또한 예산제약을 제외한 모형과 비교해서 예산제약을 고려한 모형이 모든 항목에서 비용이 증가되었다. 이는 예산제약을 고려할 경우 실제 주어진 최대 잔존수명 기간이내 매년 발생하는 예산의 최대 금액을 넘지 않은 대신에 매년 비슷한 비용으로 개량을 실시하기 때문인 것으로 판단되었다.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2002년도 학술발표회 발표논문집
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• pp.265-268
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• 2002

The ground water regime analysis method, numerical analysis method, water budget method, and baseflow analysis method have been used for estimating ground water recharged quantity. This study, adapting water budget concept of unsaturated zone, and saturated zone of the DAWAST model, proposed a new method to estimate ground water recharged quantity.