• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.394-394
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• 2023

The world's sustainable growth is being severely hampered by the inefficient use of water resources. Despite the widely acknowledged importance of trade in global and regional water and food security, societal reliance on local production as well as international trade remains inadequately assessed. Therefore, using South Korea as a case study, this study fills in this research gap by applying the virtual water concept, the logarithmic mean divisia index (LMDI) method, and the Tapio decoupling model. The virtual water concept was used to estimate South Korea's net virtual water trade for major grain crops from 1992 to 2017. Then, the LMDI method was utilized to assess the driving factors causing changes in net virtual water trade. Lastly, the Tapio decoupling model was used to investigate the decoupling relationships between economic growth and the driving factors of net virtual water trade. Results showed that South Korea remains a net importer of virtual water flows with respect to grain crops, with an average import of 16,559.24 million m³ over the study period. In addition, the change in net virtual water trade could be attributed to water intensity effect, product structure effect, economic effect, and population effect. However, water intensity and economic effects were the major decisive factors for decrease and increase in net virtual water trade respectively, while the population and product structure effects had minor positive influences on the net virtual water trade. Furthermore, water intensity and economic growth showed a strong decoupling in most periods, while the decoupling state between product structure and economic growth was observed as expansive negative decoupling. Likewise, population size and economic growth showed a weak decoupling in most periods. The results reveal South Korea's status as it concerns the virtual water trade of grain crops, thus providing valuable insights into the sustainability of trade activities for the management of local water resources.

• Journal of The Korean Society of Agricultural Engineers
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• v.57 no.3
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• pp.77-86
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• 2015

The agricultural water management generally has focused on water resources for crop production but it could be affected by the food consumption pattern. The aim of this study is to estimate virtual water consumption for food consumption and calorie supply using the water footprint and virtual water concept. In addition, we estimated the virtual water requirements for increasing the food and calorie self-sufficiency adjusted by the government for food security. About $330.0m^3/cap/yr$ of virtual water was consumed for the main foods consumption in 1985, and it was increased to $450.0m^3/cap/yr$ in 2010. The rate of virtual water consumption by meats consumption was 28 % in 1985 but it was increased to 54 % in 2010. In other words, the total virtual water consumption by foods consumption was increased from 1985 to 2010 with the high rate of meats consumption. The average $1.29m^3$ of virtual water was consumed for supplying 1 calorie per capita in 2010 but about $10.1m^3/cal$ of virtual water was consumed by only bovine meats consumption. The food self-sufficiency is the main factor for food security in Korea. About $46.5Mm^3$ and $393.9Mm^3$ of virtual water were required in order to increase the food and calorie self-sufficiency of wheat by 1 % individually. This study showed the water consumption was related to food consumption and calorie supply pattern, and these results could be used as the indices for the agricultural water management considering the change of eating habit and food security.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.211-211
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• 2020

The concept of virtual water has been largely applied in the study of regional, national, and global water flows with particular emphasis on water scarcity. Despite water traditionally being managed locally, certain global forces influence the local water resource scarcity/availability and hence virtual water exchanges worldwide. It is therefore of necessity that the significant forces be examined to understand the relationship between available water in a region and the variability and trends in environmental, social, and economic factors that are of utmost importance in the formulation of water resources management policies. This study therefore reviewed recent literature from 2003 - 2019 to determine the significant indicators of virtual water trade at different spatiotemporal levels. The study examined and compared the major approaches to virtual water trade flows accounting, and also identified and discussed policy implications and future research options concerning the analysis of virtual water trade. Available information has shown that virtual water trade is significantly influenced by economic (GDP, Demand-Supply of goods and services), geographical (Distance), institutional (population) and environmental (water availability, arable land, precipitation) factors. Reports further show that the selection of a given approach for virtual water trade flows accounting will depend on the scope of the study, the available datasets, and other research preferences. Accordingly, this study suggests that the adoption of multidisciplinary approaches to virtual water trade, taking into consideration the spatial and temporal variations in water resources availability and the complexity of environmental and socioeconomic factors will be pivotal for establishing the basis for the conservation of water resources worldwide.

• Korean Journal of Agricultural Science
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• v.44 no.4
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• pp.636-641
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• 2017

Water is an essential resource for human survival. According to the OECD Environmental Outlook to 2050, rapid industrialization and a global population increase by approximately two billion will likely increase global water use by 55% in 2050. However, water depletion has been getting worse than before and has been happening more quickly, as Earth's water resources are limited. The present study proposes water management measures by using the virtual water theory which enables water consumption measurement and the confirmation and recognition of water scarcity problems, and will support the development of counter-measures. As a method for estimating the value of agricultural water, virtual water theory was used to calculate the amount of agricultural water input for domestic rice and to apply prices of agricultural water in the United States and China to Korean water prices. When the Chinese price was applied to Korean water prices, the value of agricultural water represented 0.3% of the Korean rice producer's price. When the US price was applied to Korean water prices, the value of agricultural water represented 1.6% of the domestic rice producer's price. The study exposes the percentage of the value of agricultural water in agricultural product prices, as well as how this scare resource may affect future prices. In the future, if there are water charges to effectively manage agricultural water, this study, which uses the virtual water theory, can be used as a preliminary research.

• Journal of Korea Water Resources Association
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• v.43 no.6
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• pp.583-595
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• 2010

Virtual water is defined as the volume of water to produce commodities and provide services, which has been developed by Tony Allan since the early 1990s. This research aims to evaluate a volume of virtual water trade in Korea from 1998 to 2007 by applying the evaluation method of unit virtual water volume to agricultural, live stock and industrial products, which is developed by Chapagain and Hoekstra (2004). Also, the concept of water footprint is deployed to quantify the volume of virtual water trade between countries. The study attempts to assess the appropriateness of the evaluation method of unit virtual water volume by employing the method to calculate the total amount of agricultural products in Korea and comparing this with the amount of agricultural water demand in the Korea Water Vision 2006. The research outcome shows that Korea has a net virtual water import of 32 billion $m^3$ on average in the form of agricultural, live stock and industrial commodities whose volume gradually increases. The gap between the volume of virtual water import of agricultural and live stock commodities and the total volume of agricultural water use reaches approximately 600 million $m^3$. This figure can be negligible considering the total volume of water demand in Korea, around 16 billion $m^3$, which demonstrates the validity of the evaluation method in terms of analyzing water balance.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.161-161
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• 2022

Despite the impressive development of water infrastructure and management in recent decades, Korea still faces a number of threats to water security owing to such factors as climate change. This puts the country at the top spot amongst the Organization for Economic Co-operation and Development (OECD) countries in terms of water stress. It is suggested that increasing food imports and decreasing domestic food production can contribute to water and land savings and in extension, to increased water and land security. This study therefore aimed at analyzing the impact of virtual water import through food trade on the water and land savings in Korea. It was concluded that over the period 2000 - 2017, significant amounts of national water and land was saved through the importation of major upland crops. In addition, we estimated the virtual water trade (VWT) that refers to the trade of water embedded in food products. The results showed a significant increase in the amount of virtual water traded over the study period.

• Journal of Korea Water Resources Association
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• v.53 no.spc1
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• pp.765-772
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• 2020

The amount of water resources identified by water balance analysis are usually used to formulate water resources plans. However, this does not consider the trade in goods between countries. It is possible to use virtual water to come up with a supply and demand plan by looking at the export and import of products. This is because it looks comprehensively at the direct water use (water resources within the region) and indirect water use (water resources of other regions from imported products). Yet South Korea does not actively use the concept of virtual water in the national water resources plan. There is difficulty with calculating and identifying the appropriate virtual water amount as many of the research papers present only few of the cases or omit the calculation process. This paper introduces detailed water footprint values for calculating the virtual water trade for South Korea. The international movement, water footprint, and virtual water trade of agricultural and livestock products are presented and compared to existing research. The water footprint and virtual water research in this paper can be utilized as baseline data for future researchers.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1636-1640
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• 2006

SMAC method, one of the computational fluid dynamics techniques, is modified from the original MAC method for the time-dependent variation of flow analysis. The Navier-Stokes equations for incompressible time-dependent viscous flow are applied, and also marker particles that present the visualization of flow analysis are used. In this study SMAC technique is used to analyze the flow behavior in the water-filling of virtual channel. Then by changes of diameter of two ingates, the change of velocity and discharge when two ingates are filled the water to virtual channel are simulated. As a result, water-filling flow pattern in the virtual channel is simulated very well. Therefore, this numerical simulation will also be applied for the design of structures as open flume and porous breakwater.

• Journal of Korea Water Resources Association
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• v.53 no.9
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• pp.691-699
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• 2020

South Korea's available water resources per capita is very small compared to global average as there is a high population on small land. Thus, it is imperative to secure water resources for the safe livelihood of the citizens. As an advanced, industrialized country, South Korean economic dependence on agricultural has greatly lowered. Unless South Korea utilizes foreign water resources, it is impossible to provide agricultural and livestock products the same as current levels. However, virtual water-related research in South Korea is still inadequate. When establishing the water resources plan, it does not consider the international trade of virtual water. This research aims to solve this issue by analyzing the international virtual water trends focusing on South Korea. Consequently, the export and import of virtual water trade was identified according to country and item for 248 countries and South Korea. According to the results, South Korea's agricultural and livestock virtual water has much higher imports than exports, which outputs with agricultural by-products being the main import. In 2018, South Korea imported 72.2 billion ㎥, which is 29 times the exported amount of 2.5 billion ㎥. The research results can be used as baseline data for establishing the national water resources plan in the future.

• Journal of Ocean Engineering and Technology
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• v.14 no.3
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• pp.35-40
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• 2000

SMAC method is, one of the numerical simulation techniques, modified from the original MAC for the time-dependent variation of fluid flows. The Navier-Stokes equation for incompressible time-dependent viscous flow is applied and, also marker particles which move with the fluid are used. Two-dimensional numerical computations of fluid flow are carried out in a virtual water tank. This paper has shown very well the movements of marker particles using SMAC method.